Henry Rusinek, Ph.D.

Framingham cardiovascular risk profile correlates with impaired hippocampal and cortical vasoreactivity to hypercapnia
Glodzik, Lidia; Rusinek, Henry; Brys, Miroslaw; Tsui, Wai H; Switalski, Remigiusz; Mosconi, Lisa; Mistur, Rachel; Pirraglia, Elizabeth; de Santi, Susan; Li, Yi; Goldowsky, Alexander; de Leon, Mony J
2011 Feb;31(2):671-679, Journal of cerebral blood flow & metabolism
Vascular risk factors affect cerebral blood flow (CBF) and cerebral vascular reactivity, contributing to cognitive decline. Hippocampus is vulnerable to both Alzheimer's disease (AD) pathology and ischemia; nonetheless, the information about the impact of vascular risk on hippocampal perfusion is minimal. Cognitively, healthy elderly (NL=18, 69.9+/-6.7 years) and subjects with mild cognitive impairment (MCI=15, 74.9+/-8.1 years) were evaluated for the Framingham cardiovascular risk profile (FCRP). All underwent structural imaging and resting CBF assessment with arterial spin labeling (ASL) at 3T magnetic resonance imaging (MRI). In 24 subjects (NL=17, MCI=7), CBF was measured after a carbon dioxide rebreathing challenge. Across all subjects, FCRP negatively correlated with hippocampal (rho=-0.41, P=0.049) and global cortical (rho=-0.46, P=0.02) vasoreactivity to hypercapnia (VR(h)). The FCRP-VR(h) relationships were most pronounced in the MCI group: hippocampus (rho=-0.77, P=0.04); global cortex (rho=-0.83, P=0.02). The FCRP did not correlate with either volume or resting CBF. The hippocampal VR(h) was lower in MCI than in NL subjects (Z=-2.0, P=0.047). This difference persisted after age and FCRP correction (F([3,20])=4.6, P=0.05). An elevated risk for vascular pathology is associated with a reduced response to hypercapnia in both hippocampal and cortical tissue. The VR(h) is more sensitive to vascular burden than either resting CBF or brain volume
— id: 138222, year: 2011, vol: 31, page: 671, stat: Journal Article,

A B(1) -insensitive high resolution 2D T(1) mapping pulse sequence for dGEMRIC of the HIP at 3 Tesla
Lattanzi, Riccardo; Glaser, Christian; Mikheev, Artem V; Petchprapa, Catherine; Mossa, David J; Gyftopoulos, Soterios; Rusinek, Henry; Recht, Michael; Kim, Daniel
2011 Aug;66(2):348-355, Magnetic resonance in medicine
Early detection of cartilage degeneration in the hip may help prevent onset and progression of osteoarthritis in young patients with femoroacetabular impingement. Delayed gadolinium-enhanced MRI of cartilage is sensitive to cartilage glycosaminoglycan loss and could serve as a diagnostic tool for early cartilage degeneration. We propose a new high resolution 2D T(1) mapping saturation-recovery pulse sequence with fast spin echo readout for delayed gadolinium-enhanced magnetic resonance imaging of cartilage of the hip at 3 T. The proposed sequence was validated in a phantom and in 10 hips, using radial imaging planes, against a rigorous multipoint saturation-recovery pulse sequence with fast spin echo readout. T(1) measurements by the two pulse sequences were strongly correlated (R(2) > 0.95) and in excellent agreement (mean difference = -8.7 ms; upper and lower 95% limits of agreement = 64.5 and -81.9 ms, respectively). T(1) measurements were insensitive to B(1+) variation as large as 20%, making the proposed T(1) mapping technique suitable for 3 T. Magn Reson Med, 2011. (c) 2011 Wiley-Liss, Inc
— id: 135544, year: 2011, vol: 66, page: 348, stat: Journal Article,

Hippocampal blood flow in normal aging measured with arterial spin labeling at 3T
Rusinek, Henry; Brys, Miroslaw; Glodzik, Lidia; Switalski, Remigiusz; Tsui, Wai-Hon; Haas, Francois; McGorty, Kellyanne; Chen, Qun; de Leon, Mony J
2011 Jan;65(1):128-137, Magnetic resonance in medicine
Due to methodological difficulties related to the small size, variable distribution of hippocampal arteries, and the location of the hippocampus in the proximity of middle cranial fossa, little is known about hippocampal blood flow (HBF). We have tested the utility of a pulsed arterial spin labeling sequence based on multi-shot true fast imaging in steady precession to measure HBF in 34 normal volunteers (17 women, 17 men, 26-92 years old). Flow sensitivity to a mild hypercapnic challenge was also examined. Coregistered 3D MPRAGE sequence was used to eliminate from hippocampal and cortical regions of interest all voxel with <75% of gray matter. Large blood vessels were also excluded. HBF in normal volunteers averaged 61.2 +/- 9.0 mL/(100 g min). There was no statistically significant age or gender effect. Under a mild hypercapnia challenge (end tidal CO(2) pressure increase of 6.8 +/- 1.9 mmHg over the baseline), HBF response was 14.1 +/- 10.8 mL/(100 g min), whereas cortical gray matter flow increased by 18.0 +/- 12.2 mL/(100 g min). Flow response among women was significantly larger than in the men. The average absolute difference between two successive HBF measures was 3.6 mL/(100 g min) or 5.4%. The 3T true fast imaging in steady precession arterial spin labeling method offers a HBF measurement strategy that combines good spatial resolution, sensitivity, and minimal image distortions. Magn Reson Med, 2010. (c) 2010 Wiley-Liss, Inc
— id: 116206, year: 2011, vol: 65, page: 128, stat: Journal Article,

A dynamic method for automated lung nodule morphology characterization
Stember J.; Naidich D.; Ko J.; Rusinek H.
2011 ;6:S342-S342, International journal of computer assisted radiology & surgery
Purpose: Many potential lung cancers start out as small pulmonary nodules showing up as incidental findings on chest radiograph or computed tomography (CT) scans. Diagnosis is confirmed via biopsy, usually involving broncoscopy or CT-guided biopsy. However, these are invasive procedures that expose patients to additional risks. An alternative mode of tumor detection lies in administering successive chest CT scans. This has the advantage of avoiding those risks associated with biopsy. Overall, there is growing evidence for the effectiveness of low-dose CT for lung cancer screening. Morphology is an important indicator of malignant potential for lung nodules detected at CT. Automated methods for morphology assessment have previously been described for breast cancer visualized on mammography [1]. The most common measure of nodule shape is area-to-perimeter-length ratio (APR), low APR values being associated with spiculated or lobulated shape. APR is a static measure and thus highly susceptible to alterations by random noise and artifacts in image acquisition. We introduce and analyze the self-overlap (SO) method as a dynamic automated morphological detection scheme. SO measures the rate of change of nodule masks as a function of the radius of the blurring kernel. In other words, SO measures the degree to which a nodule's shape changes or stays intact upon successive pixel averaging that blurs the original image. Irregularities at the surface mean that a significant number of high-attenuation pixels (representing solid nodular tissue) are surrounded by low-attenuation pixels (representing air). Averaging each pixel with its neighboring pixels thus serves to trim back lobulations and spiculations from a nodule image. Hence, comparedto smooth nodules, lobulated and spiculated nodules are subject to more of this trimming upon successive averaging, so that their shape changes more, resulting in lower SO values. Due to its dynamical nature, we hypothesized that SO is more resilient to random image noise than APR. Methods: In experiment 1 we compare our algorithm with APR for nodules simulated using a spherical harmonic model (degree = 0-7) rasterized and contaminated with random noise. In experiment 2 we compare the new measure with a consensus of two expert morphology ratings of 119 nodules from clinical CT exams. Results: Experiment 1 shows that both methods display the desired trend in that APR and SO both decrease with increasing spherical harmonic degree-meaning more lobulations. As such both methods serve as measures of surface smoothness. However, SO displays significantly greater robustness to CT image noise; for both methods, we calculate variability as standard deviation over mean. We find that APR's variability in the face of random noise is on the order of ten times that of SO. This finding suggests that SO is much more robust than APR to the effects of random noise. Using a logistic regression model, in experiment 2 we achieved 89.9% agreement with the consensus assessment of two expert radiologists, versus 87.4% for APR. Conclusion: Simulation nodules show that both our dynamic method (SO) and a representative static method (APR) for automated lung nodule surface morphology determination yield clear trends as functions of surface smoothness. Hence both methods can, with proper fitting and cutoff selection, yield faithful predictions that have over 80% agreement with expert assessment. However, when the simulation nodules are subjected to random noise, SO yields much more consistent and reproducible results than APR. Overall, we conclude that our method, due to its robustness to the random noise and CT artifacts that can plague nodule images, is well suited for clinical application
— id: 136629, year: 2011, vol: 6, page: S342, stat: Journal Article,

Kidney function: glomerular filtration rate measurement with MR renography in patients with cirrhosis
Vivier, Pierre-Hugues; Storey, Pippa; Rusinek, Henry; Zhang, Jeff L; Yamamoto, Akira; Tantillo, Kristopher; Khan, Umer; Lim, Ruth P; Babb, James S; John, Devon; Teperman, Lewis W; Chandarana, Hersh; Friedman, Kent; Benstein, Judith A; Skolnik, Edward Y; Lee, Vivian S
2011 May;259(2):462-470, Radiology
PURPOSE: To assess the accuracy of glomerular filtration rate (GFR) measurements obtained with low-contrast agent dose dynamic contrast material-enhanced magnetic resonance (MR) renography in patients with liver cirrhosis who underwent routine liver MR imaging, with urinary clearance of technetium 99m ((99m)Tc) pentetic acid (DTPA) as the reference standard. MATERIALS AND METHODS: This HIPAA-compliant study was institutional review board approved. Written informed patient consent was obtained. Twenty patients with cirrhosis (14 men, six women; age range, 41-70 years; mean age, 54.6 years) who were scheduled for routine 1.5-T liver MR examinations to screen for hepatocellular carcinoma during a 6-month period were prospectively included. Five-minute MR renography with a 3-mL dose of gadoteridol was performed instead of a routine test-dose timing examination. The GFR was estimated at MR imaging with use of two kinetic models. In one model, only the signal intensities in the aorta and kidney parenchyma were considered, and in the other, renal cortical and medullary signal intensities were treated separately. The GFR was also calculated by using serum creatinine levels according to the Cockcroft-Gault and modification of diet in renal disease (MDRD) formulas. All patients underwent a (99m)Tc-DTPA urinary clearance examination on the same day to obtain a reference GFR measurement. The accuracies of all MR- and creatinine-based GFR estimations were compared by using Wilcoxon signed rank tests. RESULTS: The mean reference GFR, based on (99m)Tc-DTPA clearance, was 74.9 mL/min/1.73 m(2) +/- 27.7 (standard deviation) (range, 10.3-120.7 mL/min/1.73 m(2)). With both kinetic models, 95% of MR-based GFRs were within 30% of the reference values, whereas only 40% and 60% of Cockcroft-Gault- and MDRD-based GFRs, respectively, were within this range. MR-based GFR estimates were significantly more accurate than creatinine level-based estimates (P < .001). CONCLUSION: GFR assessment with MR imaging, which outperformed the Cockcroft-Gault and MDRD formulas, adds less than 10 minutes of table time to a clinically indicated liver MR examination without ionizing radiation. Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101338/-/DC1
— id: 134249, year: 2011, vol: 259, page: 462, stat: Journal Article,

Quantitative Evaluation of Acute Renal Transplant Dysfunction with Low-Dose Three-dimensional MR Renography
Yamamoto A; Zhang JL; Rusinek H; Chandarana H; Vivier PH; Babb JS; Diflo T; John DG; Benstein JA; Barisoni L; Stoffel DR; Lee VS
2011 Sep;260(3):781-789, Radiology
Purpose: To assess prospectively the ability of quantitative low-dose three-dimensional magnetic resonance (MR) renography to help identify the cause of acute graft dysfunction. Materials and Methods: This HIPAA-compliant study was approved by the institutional review board, and written informed consent was obtained. Between December 2001 and May 2009, sixty patients with transplanted kidneys (41 men and 19 women; mean age, 49 years; age range, 22-71 years) were included. Thirty-one patients had normal function and 29 had acute dysfunction due to acute rejection (n = 12), acute tubular necrosis (ATN) (n = 8), chronic rejection (n = 6), or drug toxicity (n = 3). MR renography was performed at 1.5 T with three-dimensional gradient-echo imaging. With use of a multicompartment renal model, the glomerular filtration rate (GFR) and the mean transit time (MTT) of the tracer for the vascular compartment (MTT(A)), the tubular compartment (MTT(T)), and the collecting system compartment (MTT(C)) were calculated. Also derived was MTT for the whole kidney (MTT(K) = MTT(A) + MTT(T) + MTT(C)) and fractional MTT of each compartment (MTT(A/K) = MTT(A)/MTT(K), MTT(T/K) = MTT(T)/MTT(K), MTT(C/K) = MTT(C)/MTT(K)). These parameters were compared in patients in the different study groups. Statistical analysis was performed by using analysis of covariance. Results: There were significant differences in GFR and MTT(K) between the acute dysfunction group (36.4 mL/min +/- 20.8 [standard deviation] and 177.1 seconds +/- 46.8, respectively) and the normal function group (65.9 mL/min +/- 27.6 and 140.5 seconds +/- 51.8, respectively) (P < .001 and P = .004). The MTT(A/K) was significantly higher in the acute rejection group (mean, 12.7% +/- 2.9) than in the normal function group (mean, 8.3% +/- 2.2; P < .001) or in the ATN group (mean, 7.1% +/- 1.4; P < .001). The MTT(T/K) was significantly higher in the ATN group (mean, 83.2% +/- 9.2) than in the normal function group (mean, 72.4% +/- 10.2; P = .031) or in the acute rejection group (mean, 69.2% +/- 6.1; P = .003). Conclusion: Low-dose MR renography analyzed by using a multicompartmental tracer kinetic renal model may help to differentiate noninvasively between acute rejection and ATN after kidney transplantation. (c) RSNA, 2011
— id: 135365, year: 2011, vol: 260, page: 781, stat: Journal Article,

Optimization of b-value sampling for diffusion-weighted imaging of the kidney
Zhang JL; Sigmund EE; Rusinek H; Chandarana H; Storey P; Chen Q; Lee VS
2011 Jan;67(1):89-97 L, Magnetic resonance in medicine
Diffusion-weighted imaging (DWI) involves data acquisitions at multiple b values. In this paper, we presented a method of selecting the b values that maximize estimation precision of the biexponential analysis of renal DWI data. We developed an error propagation factor for the biexponential model, and proposed to optimize the b-value samplings by minimizing the error propagation factor. A prospective study of four healthy human subjects (eight kidneys) was done to verify the feasibility of the proposed protocol and to assess the validity of predicted precision for DWI measures, followed by Monte Carlo simulations of DWI signals based on acquired data from renal lesions of 16 subjects. In healthy subjects, the proposed methods improved precision (P = 0.003) and accuracy (P < 0.001) significantly in region-of-interest based biexponential analysis. In Monte Carlo simulation of renal lesions, the b-sampling optimization lowered estimation error by at least 20-30% compared with uniformly distributed b values, and improved the differentiation between malignant and benign lesions significantly. In conclusion, the proposed method has the potential of maximizing the precision and accuracy of the biexponential analysis of renal DWI. Magn Reson Med, 2011. (c) 2011 Wiley-Liss, Inc
— id: 135366, year: 2011, vol: 67, page: 89, stat: Journal Article,

(99m)Tc hexamethyl-propylene-aminoxime single-photon emission computed tomography prediction of conversion from mild cognitive impairment to Alzheimer disease
Devanand, D P; Van Heertum, Ronald L; Kegeles, Lawrence S; Liu, Xinhua; Jin, Zong Hao; Pradhaban, Gnanavalli; Rusinek, Henry; Pratap, Mali; Pelton, Gregory H; Prohovnik, Isak; Stern, Yaakov; Mann, J John; Parsey, Ramin
2010 Nov;18(11):959-972, American journal of geriatric psychiatry
OBJECTIVE: To examine the utility of single-photon emission computed tomography (SPECT) to predict conversion from mild cognitive impairment (MCI) to Alzheimer disease (AD). DESIGN: Longitudinal, prospective study. SETTING: University-based memory disorders clinic. PARTICIPANTS: One hundred twenty seven patients with MCI and 59 healthy comparison subjects followed up for 1-9 years. MEASUREMENTS: Diagnostic evaluation, neuropsychological tests, social/cognitive function, olfactory identification, apolipoprotein E genotype, magnetic resonance imaging, and brain Tc hexamethyl-propylene-aminoxime SPECT scan with visual ratings, and region of interest (ROI) analyses were done. RESULTS: Visual ratings of SPECT temporal and parietal blood flow did not distinguish eventual MCI converters to AD (N = 31) from nonconverters (N = 96), but the global rating predicted conversion (41.9% sensitivity and 82.3% specificity, Fisher's exact test p = 0.013). Blood flow in each ROI was not predictive, but when dichotomized at the median value of the patients with MCI, low flow increased the hazard of conversion to AD for parietal (hazard ratio: 2.96, 95% confidence interval: 1.16-7.53, p = 0.023) and medial temporal regions (hazard ratio: 3.12, 95% confidence interval: 1.14-8.56, p = 0.027). In the 3-year follow-up sample, low parietal (p <0.05) and medial temporal (p <0.01) flow predicted conversion to AD, with or without controlling for age, Mini-Mental State Examination, and apolipoprotein E epsilon4 genotype. These measures lost significance when other strong predictors were included in logistic regression analyses: verbal memory, social/cognitive functioning, olfactory identification deficits, hippocampal, and entorhinal cortex volumes. CONCLUSIONS: SPECT visual ratings showed limited utility in predicting MCI conversion to AD. The modest predictive utility of quantified low parietal and medial temporal flow using SPECT may decrease when other stronger predictors are available
— id: 134371, year: 2010, vol: 18, page: 959, stat: Journal Article,

Diagnosis of cirrhosis with intravoxel incoherent motion diffusion MRI and dynamic contrast-enhanced MRI alone and in combination: Preliminary experience
Patel, Jignesh; Sigmund, Eric E; Rusinek, Henry; Oei, Marcel; Babb, James S; Taouli, Bachir
2010 Mar;31(3):589-600, Journal of magnetic resonance imaging
PURPOSE:: To report our preliminary experience with the use of intravoxel incoherent motion (IVIM) diffusion-weighted magnetic resonance imaging (DW-MRI) and dynamic contrast-enhanced (DCE)-MRI alone and in combination for the diagnosis of liver cirrhosis. MATERIALS AND METHODS:: Thirty subjects (16 with noncirrhotic liver, 14 with cirrhosis) were prospectively assessed with IVIM DW-MRI (n = 27) and DCE-MRI (n = 20). IVIM parameters included perfusion fraction (PF), pseudodiffusion coefficient (D*), true diffusion coefficient (D), and apparent diffusion coefficient (ADC). Model-free DCE-MR parameters included time to peak (TTP), upslope, and initial area under the curve at 60 seconds (IAUC60). A dual input single compartmental perfusion model yielded arterial flow (Fa), portal venous flow (Fp), arterial fraction (ART), mean transit time (MTT), and distribution volume (DV). The diagnostic performances for diagnosis of cirrhosis were evaluated for each modality alone and in combination using logistic regression and receiver operating characteristic analyses. IVIM and DCE-MR parameters were compared using a generalized estimating equations model. RESULTS:: PF, D*, D, and ADC values were significantly lower in cirrhosis (P = 0.0056-0.0377), whereas TTP, DV, and MTT were significantly increased in cirrhosis (P = 0.0006-0.0154). There was no correlation between IVIM- and DCE-MRI parameters. The highest Az (areas under the curves) values were observed for ADC (0.808) and TTP-DV (0.952 for each). The combination of ADC with DV and TTP provided 84.6% sensitivity and 100% specificity for diagnosis of cirrhosis. CONCLUSION:: The combination of DW-MRI and DCE-MRI provides an accurate diagnosis of cirrhosis. J. Magn. Reson. Imaging 2010;31:589-600. (c) 2010 Wiley-Liss, Inc
— id: 107780, year: 2010, vol: 31, page: 589, stat: Journal Article,

Segmentation of Polycystic Kidneys from MR images
Racimora, D.; Vivier, P.-H.; Chandarana, H.; Rusinek, H.
2010 ;:7624W-7624W, Proceedings of SPIE (The International Society for Optical Engineering)
Polycystic kidney disease (PKD) is a disorder characterized by the growth of numerous fluid filled cysts in the kidneys. Measuring cystic kidney volume is thus crucial to monitoring the evolution of the disease. While T2-weighted MRI delineates the organ, automatic segmentation is very difficult due to highly variable shape and image contrast. The interactive stereology methods used currently involve a compromise between segmentation accuracy and time. We have investigated semi-automated methods: active contours and a sub-voxel morphology based algorithm. Coronal T2-weighted images of 17 patients were acquired in four breath-holds using the HASTE sequence on a 1.5 Tesla MRI unit. The segmentation results were compared to ground truth kidney masks obtained as a consensus of experts. Automatic active contour algorithm yielded an average 22% +/- 8.6% volume error. A recently developed method (Bridge Burner) based on thresholding and constrained morphology failed to separate PKD from the spleen, yielding 37.4% +/- 8.7% volume error. Manual post-editing reduced the volume error to 3.2% +/- 0.8% for active contours and 3.2% +/- 0.6% for Bridge Burner. The total time (automated algorithm plus editing) was 15 min +/- 5 min for active contours and 19 min +/- 11 min for Bridge Burner. The average volume errors for stereology method were 5.9%, 6.2%, 5.4% for mesh size 6.6, 11, 16.5 mm. The average processing times were 17, 7, 4 min. These results show that nearly two-fold improvement in PKD segmentation accuracy over stereology technique can be achieved with a combination of active contours and post-editing
— id: 115900, year: 2010, vol: , page: 7624W, stat: Journal Article,

An automated three-dimensional plus time registration framework for dynamic MR renography
Song, T; Lee, VS; Chen, Q; Rusinek, H; Laine, AF
2010 JAN ;21(1):1-8, Journal of visual communication & image representation
Dynamic contrast-enhanced 3D images of the kidneys, or 3D MR renography, has the potential for broad clinical applications, but suffers from respiratory motion that limits analysis and interpretation. Manual registration is prohibitively labor-intensive. In this paper, a fully automated technique, Wavelet Representation and the Fourier Transform (WRFT) method, that corrects for translation and rotation motion in 3D MR renography is presented. The method was composed by anisotropic denoising, wavelet-based feature extraction, and Fourier-based registration. This was first evaluated on a set of simulated MR renography images with defined degrees of kidney motion. The method was then tested on 24 clinical patient MR renography data sets. Results of clinical testing were compared with the results obtained using a mutual information registration method. Based on intrarenal time-intensity curves, our method showed robust and consistent agreement with the results of manually coregistered data sets. (C) 2009 Elsevier Inc. All rights reserved
— id: 106523, year: 2010, vol: 21, page: 1, stat: Journal Article,

GLOMERULAR FILTRATION RATE IN CIRRHOTIC PATIENTS BY MR RENOGRAPHY
Vivier, Pierre-Hugues; Storey, Pippa; Rusinek, Henry; Zhang, Jeff L.; Yamamoto, Akira; Tantillo, Kristopher; Lim, Ruth P.; Khan, Umer A.; Babb, James; John, Devon G.; Teperman, Lewis W.; Friedman, Kent P.; Benstein, Judith; Skolnik, Edward; Lee, Vivian S.
2010 OCT ;52(4):963A-964A, Hepatology
— id: 130850, year: 2010, vol: 52, page: 963A, stat: Journal Article,

Variability of renal apparent diffusion coefficients: limitations of the monoexponential model for diffusion quantification
Zhang, Jeff L; Sigmund, Eric E; Chandarana, Hersh; Rusinek, Henry; Chen, Qun; Vivier, Pierre-Hugues; Taouli, Bachir; Lee, Vivian S
2010 Mar;254(3):783-792, Radiology
Purpose: To investigate whether variability in reported renal apparent diffusion coefficient (ADC) values in literature can be explained by the use of different diffusion weightings (b values) and the use of a monoexponential model to calculate ADC. Materials and Methods: This prospective study was approved by institutional review board and was HIPAA-compliant, and all subjects gave written informed consent. Diffusion-weighted (DW) imaging of the kidneys was performed in three healthy volunteers to generate reference diffusion decay curves. In a literature meta-analysis, the authors resampled the reference curves at the various b values used in 19 published studies of normal kidneys (reported ADC = [2.0-4.1] x 10(-3) mm(2) / sec for cortex and [1.9-5.1] x 10(-3) mm(2) / sec for medulla) and then fitted the resampled signals by monoexponential model to produce 'predicted' ADC. Correlation plots were used to compare the predicted ADC values with the published values obtained with the same b values. Results: Significant correlation was found between the reported and predicted ADC values for whole renal parenchyma (R(2) = 0.50, P = .002), cortex (R(2) = 0.87, P = .0002), and medulla (R(2) = 0.61, P = .0129), indicating that most of the variability in reported ADC values arises from limitations of a monoexponential model and use of different b values. Conclusion: The use of a monoexponential function for DW imaging analysis and variably sampled diffusion weighting plays a substantial role in causing the variability in ADC of healthy kidneys. For maximum reliability in renal apparent diffusion coefficient quantification, data for monoexponential analysis should be acquired at a fixed set of b values or a biexponential model should be used. (c) RSNA, 2010
— id: 111628, year: 2010, vol: 254, page: 783, stat: Journal Article,

Estimates of glomerular filtration rate from MR renography and tracer kinetic models
Bokacheva, Louisa; Rusinek, Henry; Zhang, Jeff L; Chen, Qun; Lee, Vivian S
2009 Feb;29(2):371-382, Journal of magnetic resonance imaging
PURPOSE: To compare six methods for calculating the single-kidney glomerular filtration rate (GFR) from T(1)-weighted magnetic resonance (MR) renography (MRR) against reference radionuclide measurements. MATERIALS AND METHODS: In 10 patients, GFR was determined using six published methods: the Baumann-Rudin model (BR), the Patlak-Rutland method (PR), the two-compartment model without bolus dispersion (2C) and with dispersion (2CD), the three-compartment model (3CD), and the distributed parameter model (3C-IRF). Reference single-kidney GFRs were measured by radionuclide renography. The coefficient of variation of GFR (CV) was determined for each method by Monte Carlo analyses for one healthy and one dysfunctional kidney at a noise level (sigma(n)) of 2%, 5%, and 10%. RESULTS: GFR estimates in patients varied from 6% overestimation (BR) to 50% underestimation (PR and 2CD applied to cortical data). Correlations with reference GFRs ranged from R = 0.74 (2CD, cortical data) to R = 0.85 (BR). In simulations, the lowest CV was produced by 3C-IRF in healthy kidney (1.7sigma(n)) and by PR in diseased kidney ((2.2-2.4)sigma(n)). In both kidneys the highest CV was obtained with 2CD ((5.9-8.2)sigma(n)) and with 3CD in diseased kidney (8.9sigma(n) at sigma(n) = 10%). CONCLUSION: GFR estimates depend on the renal model and type of data used. Two- and three-compartment models produce comparable GFR correlations
— id: 96683, year: 2009, vol: 29, page: 371, stat: Journal Article,

Magnetic resonance imaging improves cerebrospinal fluid biomarkers in the early detection of Alzheimer's disease
Brys, Miroslaw; Glodzik, Lidia; Mosconi, Lisa; Switalski, Remigiusz; De Santi, Susan; Pirraglia, Elizabeth; Rich, Kenneth; Kim, Byeong C; Mehta, Pankaj; Zinkowski, Ray; Pratico, Domenico; Wallin, Anders; Zetterberg, Henrik; Tsui, Wai H; Rusinek, Henry; Blennow, Kaj; de Leon, Mony J
2009 Feb;16(2):351-362, Journal of Alzheimer's Disease
Little is known of combined utility of magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) biomarkers for prediction of Alzheimer's disease (AD) and longitudinal data is scarce. We examined these biomarkers at baseline and longitudinally in incipient AD. Forty-five subjects [21 controls (NL-NL), 16 stable MCI (MCI-MCI), 8 MCI who declined to AD (MCI-AD)] received MRI and lumbar puncture at baseline and after 2 years. CSF measures included total and phosphorylated tau (T-tau, P-tau<formula>_{231}</formula>), amyloid-beta (Abeta<formula>_{42}</formula>/Abeta<formula>_{40}</formula>) and isoprostane. Voxel-based morphometry identified gray matter concentration (GMC) differences best distinguishing study groups and individual GMC values were calculated. Rate of medial temporal lobe (MTL) atrophy was examined using regional boundary shift (rBS) method. At baseline, for MRI, MCI-AD showed reduced GMC-MTL, and for CSF higher CSF T-tau, P-tau<formula>_{231}</formula>, IP and lower Abeta<formula>_{42}</formula>/Abeta<formula>_{40}</formula> as compared with MCI-MCI or NL-NL. Longitudinally, rBS-MTL atrophy was higher in MCI-AD than in either MCI-MCI or NL-NL, particularly in the left hemisphere. CSF data showed longitudinally greater increases of isoprostane in MCI-AD as compared with NL-NL. Combining baseline CSF-P-tau<formula>_{231}</formula> and GMC-MTL significantly increased overall prediction of AD from 74% to 84% (p<formula>_{step}</formula> < 0.05). These results provide support for including multiple modalities of biomarkers in the identification of memory clinic patients at increased risk for dementia
— id: 93784, year: 2009, vol: 16, page: 351, stat: Journal Article,

Dynamic contrast-enhanced MR imaging of the liver: current status and future directions
Do, Richard Kinh Gian; Rusinek, Henry; Taouli, Bachir
2009 May;17(2):339-349, Magnetic resonance imaging clinics of North America
Dynamic contrast-enhanced magnetic resonance imaging (DCE-MR imaging) is emerging as a tool that can quantify changes in liver perfusion that occur in both diffuse and focal liver diseases. Recent data show promise for DCE-MR imaging of the liver in diagnosing fibrosis and cirrhosis before morphologic changes can be detected. It may also be valuable in the assessment of hepatocellular carcinoma and liver metastases. Acquisition parameters, postprocessing methods, applications, and recent results of DCE-MR imaging of the liver are also described. Finally, it reviews the limitations and future directions of DCE-MR imaging for liver applications
— id: 98010, year: 2009, vol: 17, page: 339, stat: Journal Article,

MR spectroscopy indicates diffuse multiple sclerosis activity during remission
Kirov, I I; Patil, V; Babb, J S; Rusinek, H; Herbert, J; Gonen, O
2009 Dec;80(12):1330-1336, Journal of neurology neurosurgery & psychiatry
OBJECTIVE: To test the hypothesis that diffuse abnormalities precede axonal damage and atrophy in the MRI normal-appearing tissue of relapsing-remitting (RR) multiple sclerosis (MS) patients, and that these processes continue during clinical remission. METHODS: Twenty-one recently diagnosed mildly disabled (mean disease duration 2.3 years, mean Expanded Disability Status Scale score of 1.4) RR MS patients and 15 healthy matched controls were scanned with MRI and proton MR spectroscopic imaging ((1)H-MRSI) at 3 T. Metabolite concentrations: N-acetylaspartate (NAA) for neuronal integrity; choline (Cho) for membrane turnover rate; creatine (Cr) and myo-inositol (mI) for glial status were obtained in a 360 cm(3) volume of interest (VOI) with 3D multivoxel (1)H-MRSI. They were converted into absolute amounts using phantom replacement and normalised into absolute concentrations by dividing by the VOI tissue volume fraction obtained from MRI segmentation. RESULTS: The patients' mean VOI tissue volume fraction, 0.92 and NAA concentration, 9.6 mM, were not different from controls' 0.94 and 9.6 mM. In contrast, the patients' mean Cr, Cho and mI levels 7.7, 1.9 and 4.1 mM were 9%, 14% and 20%, higher than the controls' 7.1, 1.6 and 3.4 mM (p = 0.0097, 0.003 and 0.0023). CONCLUSIONS: The absence of early tissue atrophy and apparent axonal dysfunction (NAA loss) in these RR MS patients suggests that both are preceded by diffuse glial proliferation (astrogliosis), as well as possible inflammation, demyelination and remyelination reflected by elevated mI, Cho and Cr, even during clinical remission and despite immunomodulatory treatment
— id: 105333, year: 2009, vol: 80, page: 1330, stat: Journal Article,

Three-dimensional electrocardiographically gated variable flip angle FSE imaging for MR angiography of the hands at 3.0 T: initial experience
Lim, Ruth P; Storey, Pippa; Atanasova, Iliyana P; Xu, Jian; Hecht, Elizabeth M; Babb, James S; Stoffel, David R; Chang, Hugo; McGorty, Kellyanne; Chen, Qun; Rusinek, Henry; Belmont, H Michael; Lee, Vivian S
2009 Sep;252(3):874-881, Radiology
After institutional review board approval and informed consent were obtained for this HIPAA-compliant investigation, a three-dimensional electrocardiographically gated variable flip angle (VFA) fast spin-echo magnetic resonance (MR) angiography technique was evaluated as an unenhanced method for imaging hand arteries in 13 subjects (including four patients) at 3.0 T; this included evaluation of vessel visualization with warming and cooling in seven subjects. Examinations were evaluated for image quality and vessel conspicuity. Clear separation of arteries from veins was achieved in all subjects, with excellent vessel conspicuity and depiction of stenoses. Warming improved vessel visualization in healthy volunteers. VFA MR angiography is a high-spatial-resolution technique that enables the assessment of vascular reactivity in response to temperature challenge
— id: 101951, year: 2009, vol: 252, page: 874, stat: Journal Article,

Optimal k-space sampling for dynamic contrast-enhanced MRI with an application to MR renography
Song, Ting; Laine, Andrew F; Chen, Qun; Rusinek, Henry; Bokacheva, Louisa; Lim, Ruth P; Laub, Gerhard; Kroeker, Randall; Lee, Vivian S
2009 Feb 19;61(5):1242-1248, Magnetic resonance in medicine
For time-resolved acquisitions with k-space undersampling, a simulation method was developed for selecting imaging parameters based on minimization of errors in signal intensity versus time and physiologic parameters derived from tracer kinetic analysis. Optimization was performed for time-resolved angiography with stochastic trajectories (TWIST) algorithm applied to contrast-enhanced MR renography. A realistic 4D phantom comprised of aorta and two kidneys, one healthy and one diseased, was created with ideal tissue time-enhancement pattern generated using a three-compartment model with fixed parameters, including glomerular filtration rate (GFR) and renal plasma flow (RPF). TWIST acquisitions with different combinations of sampled central and peripheral k-space portions were applied to this phantom. Acquisition performance was assessed by the difference between simulated signal intensity (SI) and calculated GFR and RPF and their ideal values. Sampling of the 20% of the center and 1/5 of the periphery of k-space in phase-encoding plane and data-sharing of the remaining 4/5 minimized the errors in SI (<5%), RPF, and GFR (both <10% for both healthy and diseased kidneys). High-quality dynamic human images were acquired with optimal TWIST parameters and 2.4 sec temporal resolution. The proposed method can be generalized to other dynamic contrast-enhanced MRI applications, e.g., MR angiography or cancer imaging. Magn Reson Med, 2009. (c) 2009 Wiley-Liss, Inc
— id: 96682, year: 2009, vol: 61, page: 1242, stat: Journal Article,

Use of cardiac output to improve measurement of input function in quantitative dynamic contrast-enhanced MRI
Zhang, Jeff L; Rusinek, Henry; Bokacheva, Louisa; Chen, Qun; Storey, Pippa; Lee, Vivian S
2009 Sep;30(3):656-665, Journal of magnetic resonance imaging
PURPOSE: To validate a new method for converting MR arterial signal intensity versus time curves to arterial input functions (AIFs). MATERIALS AND METHODS: The method constrains AIF with patient's cardiac output (Q). Monte Carlo simulations of MR renography and tumor perfusion protocols were carried out for comparison with two alternative methods: direct measurement and population-averaged input function. MR renography was performed to assess the method's inter- and intraday reproducibility for renal parameters. RESULTS: In simulations of tumor perfusion, the precision of the parameters (K(trans) and v(e)) computed using the proposed method was improved by at least a factor of three compared to direct measurement. Similar improvements were obtained in simulations of MR renography. Volunteer study for testing interday reproducibility confirmed the improvement of precision in renal parameters when using the proposed method compared to conventional methods. In another patient study (two injections within one session), the proposed method significantly increased the correlation coefficient (R) between GFR of the two exams (0.92 vs. 0.83) compared to direct measurement. CONCLUSION: A new method significantly improves the precision of dynamic contrast-enhanced (DCE) parameters. The method may be especially useful for analyzing repeated DCE examinations, such as monitoring tumor therapy or angiotensin converting enzyme-inhibitor renography. J. Magn. Reson. Imaging 2009;30:656-665. (c) 2009 Wiley-Liss, Inc
— id: 101962, year: 2009, vol: 30, page: 656, stat: Journal Article,

Angiotensin-Converting Enzyme Inhibitor-Enhanced MR Renography: Repeated Measures of GFR and RPF in Hypertensive Patients
Zhang, Jeff L; Rusinek, Henry; Bokacheva, Louisa; Lim, Ruth P; Chen, Qun; Storey, Pippa; Prince, Keyma; Hecht, Elizabeth M; Kim, Danny C; Lee, Vivian S
2009 Apr;296(4):F884-F891, American journal of physiology. Renal physiology
This study aims to assess the feasibility of a protocol to diagnose renovascular disease using dual MR renography (MRR) acquisitions: before and after administration of angiotensin converting enzyme inhibitor (ACEi). Results of our simulation study aimed at testing the reproducibility of glomerular filtration rate (GFR) and renal plasma flow (RPF) demonstrate that for a fixed overall dose of 12 ml gadolinium-based contrast material (500 mmol/L), the second dose should be approximately twice as large as the first dose. A three-compartment model for analyzing the second-injection data was shown to appropriately handle the tracer residue from the first injection. The optimized protocol was applied to 18 hypertensive patients without renovascular disease, showing minimal systematic difference in GFR measurements before and after ACEi of 0.8+/-4.4 ml/min or 2.7%+/-14.9%. For 10 kidneys with significant renal artery stenosis, GFR decreased significantly after ACEi (P < 0.001, T-value = 3.79), and the difference in GFR measurements before and after ACEi averaged 8.3+/-6.9 ml/min or 26.2%+/-43.9%. Dual-injection MRI with optimized dose distribution appears promising for ACEi renography by offering measures of GFR changes with clinically acceptable precision and accuracy. Key words: angiotensin converting enzyme inhibitor, glomerular filtration rate, renovascular disease, compartmental modeling
— id: 92190, year: 2009, vol: 296, page: F884, stat: Journal Article,

Off-center magnetic resonance imaging with permanent magnets
Abele, MG; Rusinek, H
2008 APR 1 ;103(7):267-280, Journal of applied physics
Magnets for magnetic resonance imaging are currently designed as structures that are symmetric with respect to the geometric center O of the magnet cavity. This symmetry results in a symmetric field configuration, where point O coincides with the imaging center S defined as the point where the field gradient is zero. However, in many clinical applications such as breast or spine imaging, the region of interest is displaced from the geometric center. We present a design method for yokeless permanent magnets, where the position of point S is dictated by the imaging requirements. The magnet is composed of uniformly magnetized triangular prisms and it does not require a ferromagnetic yoke to channel the magnetic flux. Given an arbitrary polygonal cavity, the design depends on the position of point F, where the magnetostatic potential is assumed to be equal to the magnetostatic potential of the external medium. For a long magnet, the position of the imaging center S coincides with point F. As an example of the off-center design, we analyze a three-dimensional yokeless magnet with cavity of width=length=80 cm and height=45 cm. The magnet generates a field above 0.5 T when constructed using the NdFeB alloy of remanence larger than 1.3 T. The off-center configuration offers flexibility in magnet design that makes it possible to focus on a particular region of the human body, without increasing magnet cavity, magnet size, or its weight. (c) 2008 American Institute of Physics
— id: 98140, year: 2008, vol: 103, page: 267, stat: Journal Article,

Assessment of renal function with dynamic contrast-enhanced MR imaging
Bokacheva, Louisa; Rusinek, Henry; Zhang, Jeff L; Lee, Vivian S
2008 Nov;16(4):597-611, viii, Magnetic resonance imaging clinics of North America
MR imaging is a promising noninvasive modality that can provide a comprehensive picture of renal anatomy and function in a single examination. The advantages of MR imaging are its high contrast and temporal resolution and lack of exposure to ionizing radiation. In the past few years, considerable progress has been made in development of methods of renal functional MR imaging and their applications in various diseases. This article reviews the key factors for acquisition and analysis of dynamic contrast-enhanced renal MR imaging (MR renography) and the most significant developments in this field over the past few years
— id: 91450, year: 2008, vol: 16, page: 597, stat: Journal Article,

Advanced liver fibrosis: diagnosis with 3D whole-liver perfusion MR imaging--initial experience
Hagiwara, Mari; Rusinek, Henry; Lee, Vivian S; Losada, Mariela; Bannan, Michael A; Krinsky, Glenn A; Taouli, Bachir
2008 Mar;246(3):926-934, Radiology
Institutional review board approval and informed consent were obtained for this HIPAA-compliant study. The purpose of this study was to prospectively evaluate sensitivity and specificity of various estimated perfusion parameters at three-dimensional (3D) perfusion magnetic resonance (MR) imaging of the liver in the diagnosis of advanced liver fibrosis (stage >or= 3), with histologic analysis, liver function tests, or MR imaging as the reference standard. Whole-liver 3D perfusion MR imaging was performed in 27 patients (17 men, 10 women; mean age, 55 years) after dynamic injection of 8-10 mL of gadopentetate dimeglumine. The following estimated perfusion parameters were measured with a dual-input single-compartment model: absolute arterial blood flow (F(a)), absolute portal venous blood flow (F(p)), absolute total liver blood flow (F(t)) (F(t) = F(a) + F(p)), arterial fraction (ART), portal venous fraction (PV), distribution volume (DV), and mean transit time (MTT) of gadopentetate dimeglumine. Patients were assigned to two groups (those with fibrosis stage <or= 2 and those with fibrosis stage >or= 3), and the nonparametric Mann-Whitney test was used to compare F(a), F(p), F(t), ART, PV, DV, and MTT between groups. Receiver operating characteristic curve analysis was used to assess the utility of perfusion estimates as predictors of advanced liver fibrosis. There were significant differences for all perfusion MR imaging-estimated parameters except F(p) and F(t). There was an increase in F(a), ART, DV, and MTT and a decrease in PV in patients with advanced fibrosis compared with those without advanced fibrosis. DV had the best performance, with an area under the receiver operating characteristic curve of 0.824, a sensitivity of 76.9% (95% confidence interval: 46.2%, 94.7%), and a specificity of 78.5% (95% confidence interval: 49.2%, 95.1%) in the prediction of advanced fibrosis
— id: 76458, year: 2008, vol: 246, page: 926, stat: Journal Article,

Global average gray and white matter N-acetylaspartate concentration in the human brain
Inglese, Matilde; Rusinek, Henry; George, Ilena C; Babb, James S; Grossman, Robert I; Gonen, Oded
2008 Jun;41(2):270-276, Neuroimage
Since the amino acid derivative N-acetylaspartate (NAA) is almost exclusive to neuronal cells in the adult mammalian brain and its concentration has shown local (or global) abnormalities in most focal (or diffuse) neurological diseases, it is considered a specific neuronal marker. Yet despite its biological and clinical prominence, the relative NAA concentration in the gray and white matter (GM, WM) remains controversial, with each reported to be higher than, equal to, or less than the other. To help resolve the controversy and importantly, access the NAA in both compartments in their entirety, we introduce a new approach to distinguish and quantify the whole-brain average GM and WM NAA concentration by integrating MR-image segmentation, localized and non-localized quantitative (1)H-MRS. We demonstrate and validate the method in ten healthy volunteers (5 women) 27+/-6 years old (mean+/-standard-deviation) at 1.5T. The results show that the healthy adult human brain comprises significantly less WM, 39+/-3%, than GM 60+/-4% by volume (p<0.01). Furthermore, the average NAA concentration in the WM, 9.5+/-1.0 mM, is significantly lower than in GM, 14.3+/-1.1 mM (p<0.01)
— id: 79422, year: 2008, vol: 41, page: 270, stat: Journal Article,

Regional analysis of FDG and PIB-PET images in normal aging, mild cognitive impairment, and Alzheimer's disease
Li, Yi; Rinne, Juha O; Mosconi, Lisa; Pirraglia, Elizabeth; Rusinek, Henry; DeSanti, Susan; Kemppainen, Nina; Nagren, Kjell; Kim, Byeong-Chae; Tsui, Wai; de Leon, Mony J
2008 Dec;35(12):2169-2181, European journal of nuclear medicine & molecular imaging
OBJECTIVE: The objective of the study is to compare the diagnostic value of regional sampling of the cerebral metabolic rate of glucose metabolism (MRglc) using [18F]-fluoro-2-deoxyglucose ([18F]FDG)-positron emission tomography (PET) and amyloid-beta pathology using Pittsburgh Compound-B ([11C]PIB)-PET in the evaluation of patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI) compared to normal elderly (NL). MATERIALS AND METHODS: AD patients, 7 NL, 13 MCI, and 17, received clinical, neuropsychological, magnetic resonance imaging (MRI), FDG, and PIB-PET exams. Parametric images of PIB uptake and MRglc were sampled using automated regions-of-interest (ROI). RESULTS: AD showed global MRglc reductions, and MCI showed reduced hippocampus (HIP) and inferior parietal lobe (IP) MRglc compared to NL. On PIB, AD patients showed significantly increased uptake in the middle frontal gyrus (MFG), posterior cingulate cortex (PCC), and IP (ps < 0.05). PIB uptake in MCI subjects was either AD or NL-like. HIP MRglc and MFG PIB uptake were the best discriminators of NL from MCI and NL from AD. These two best measures showed high diagnostic agreement for AD (94%) and poor agreement for MCI (54%). For the NL vs. MCI discrimination, combining the two best measures increased the accuracy for PIB (75%) and for FDG (85%) to 90%. CONCLUSION: For AD, the pattern of regional involvement for FDG and PIB differ, but both techniques show high diagnostic accuracy and 94% case by case agreement. In the classification of NL and MCI, FDG is superior to PIB, but there is only 54% agreement at a case level. Combining the two modalities improves the diagnostic accuracy for MCI
— id: 96315, year: 2008, vol: 35, page: 2169, stat: Journal Article,

Fully automatic segmentation of the brain from T1-weighted MRI using Bridge Burner algorithm
Mikheev, Artem; Nevsky, Gregory; Govindan, Siddharth; Grossman, Robert; Rusinek, Henry
2008 Jun;27(6):1235-1241, Journal of magnetic resonance imaging
PURPOSE: To validate Bridge Burner, a new brain segmentation algorithm based on thresholding, connectivity, surface detection, and a new operator of constrained growing. MATERIALS AND METHODS: T1-weighted MR images were selected at random from three previous neuroimaging studies to represent a spectrum of system manufacturers, pulse sequences, subject ages, genders, and neurological conditions. The ground truth consisted of brain masks generated manually by a consensus of expert observers. All cases were segmented using a common set of parameters. RESULTS: Bridge Burner segmentation errors were 3.4% +/- 1.3% (volume mismatch) and 0.34 +/- 0.17 mm (surface mismatch). The disagreement among experts was 3.8% +/- 2.0% (volume mismatch) and 0.48 +/- 0.49 mm (surface mismatch). The error obtained using the brain extraction tool (BET), a widely used brain segmentation program, was 8.3% +/- 9.1%. Bridge Burner brain masks are visually similar to the masks generated by human experts. Areas affected by signal intensity nonuniformity artifacts were occasionally undersegmented, and meninges and large sinuses were often falsely classified as the brain tissue. Segmentation of one MRI dataset takes seven seconds. CONCLUSION: The new fully automatic algorithm appears to provide accurate brain segmentation from high-resolution T1-weighted MR images
— id: 86546, year: 2008, vol: 27, page: 1235, stat: Journal Article,

Hippocampal hypometabolism predicts cognitive decline from normal aging
Mosconi, Lisa; De Santi, Susan; Li, Juan; Tsui, Wai Hon; Li, Yi; Boppana, Madhu; Laska, Eugene; Rusinek, Henry; de Leon, Mony J
2008 May;29(5):676-692, Neurobiology of aging
OBJECTIVE: This longitudinal study used FDG-PET imaging to predict and monitor cognitive decline from normal aging. METHODS: Seventy-seven 50-80-year-old normal (NL) elderly received longitudinal clinical examinations over 6-14 years (561 person-years, mean per person 7.2 years). All subjects had a baseline FDG-PET scan and 55 subjects received follow-up PET exams. Glucose metabolic rates (MRglc) in the hippocampus and cortical regions were examined as predictors and correlates of clinical decline. RESULTS: Eleven NL subjects developed dementia, including six with Alzheimer's disease (AD), and 19 declined to mild cognitive impairment (MCI), on average 8 years after the baseline exam. The baseline hippocampal MRglc predicted decline from NL to AD (81% accuracy), including two post-mortem confirmed cases, from NL to other dementias (77% accuracy), and from NL to MCI (71% accuracy). Greater rates of hippocampal and cortical MRglc reductions were found in the declining as compared to the non-declining NL. CONCLUSIONS: Hippocampal MRglc reductions using FDG-PET during normal aging predict cognitive decline years in advance of the clinical diagnosis. Future studies are needed to increase preclinical specificity in differentiating dementing disorders
— id: 70030, year: 2008, vol: 29, page: 676, stat: Journal Article,

Functional assessment of the kidney from magnetic resonance and computed tomography renography: impulse retention approach to a multicompartment model
Zhang, Jeff L; Rusinek, Henry; Bokacheva, Louisa; Lerman, Lilach O; Chen, Qun; Prince, Chekema; Oesingmann, Niels; Song, Ting; Lee, Vivian S
2008 Feb;59(2):278-288, Magnetic resonance in medicine
A three-compartment model is proposed for analyzing magnetic resonance renography (MRR) and computed tomography renography (CTR) data to derive clinically useful parameters such as glomerular filtration rate (GFR) and renal plasma flow (RPF). The model fits the convolution of the measured input and the predefined impulse retention functions to the measured tissue curves. A MRR study of 10 patients showed that relative root mean square errors by the model were significantly lower than errors for a previously reported three-compartmental model (11.6% +/- 4.9 vs 15.5% +/- 4.1; P < 0.001). GFR estimates correlated well with reference values by (99m)Tc-DTPA scintigraphy (correlation coefficient r = 0.82), and for RPF, r = 0.80. Parameter-sensitivity analysis and Monte Carlo simulation indicated that model parameters could be reliably identified. When the model was applied to CTR in five pigs, expected increases in RPF and GFR due to acetylcholine were detected with greater consistency than with the previous model. These results support the reliability and validity of the new model in computing GFR, RPF, and renal mean transit times from MR and CT data
— id: 78637, year: 2008, vol: 59, page: 278, stat: Journal Article,

Quantitative determination of Gd-DTPA concentration in T1-weighted MR renography studies
Bokacheva, Louisa; Rusinek, Henry; Chen, Qun; Oesingmann, Niels; Prince, Chekema; Kaur, Manmeen; Kramer, Elissa; Lee, Vivian S
2007 Jun;57(6):1012-1018, Magnetic resonance in medicine
A method for calculating contrast agent concentration from MR signal intensity (SI) was developed and validated for T(1)-weighted MR renography (MRR) studies. This method is based on reference measurements of SI and relaxation time T(1) in a Gd-DTPA-doped water phantom. The same form of SI vs. T(1) dependence was observed in human tissues. Contrast concentrations calculated by the proposed method showed no bias between 0 and 1 mM, and agreed better with the reference values derived from direct T(1) measurements than the concentrations calculated using the relative signal method. Phantom-based conversion was used to determine the contrast concentrations in kidney tissues of nine patients who underwent dynamic Gd-DTPA-enhanced 3D MRR at 1.5T and (99m)Tc-DTPA radionuclide renography (RR). The concentrations of both contrast agents were found to be close in magnitude and showed similar uptake and washout behavior. As shown by Monte Carlo simulations, errors in concentration due to SI noise were below 10% for SNR = 20, while a 10% error in precontrast T(1) values resulted in a 12-17% error for concentrations between 0.1 and 1 mM. The proposed method is expected to be particularly useful for assessing regions with highly concentrated contrast
— id: 73255, year: 2007, vol: 57, page: 1012, stat: Journal Article,

Proton MR spectroscopy and MRI-volumetry in mild traumatic brain injury
Cohen, B A; Inglese, M; Rusinek, H; Babb, J S; Grossman, R I; Gonen, O
2007 May;28(5):907-913, AJNR. American journal of neuroradiology
BACKGROUND AND PURPOSE: More than 85% of brain traumas are classified as 'mild'; MR imaging findings are minimal if any and do not correspond to clinical symptoms. Our goal, therefore, was to quantify the global decline of the neuronal marker N-acetylaspartate (NAA), as well as gray (GM) and white matter (WM) atrophy after mild traumatic brain injury (mTBI). MATERIALS AND METHODS: Twenty patients (11 male, 9 female; age range, 19-57 years; median, 35 years) with mTBI (Glasgow Coma Scale score 13-15 with loss of consciousness for at least 30 seconds) and 19 age- and sex-matched control subjects were studied. Seven patients were studied within 9 days of TBI; the other 13 ranged from 1.2 months to 31.5 years (average and median of 4.6 and 1.7 years, respectively) after injury. Whole-brain NAA (WBNAA) concentration was obtained in all subjects with nonlocalizing proton MR spectroscopy. Brain volume and GM and WM fractions were segmented from T1-weighted MR imaging and normalized to the total intracranial volume, suitable for intersubject comparisons. The data were analyzed with least squares regression. RESULTS: Patients with mTBI exhibited, on average, a 12% WBNAA deficit that increased with age, compared with the control subjects (p<.05). Adjusted for age effects, patients also suffered both global atrophy (-1.09%/year; P=.029) and GM atrophy (-0.89%/year; P=.042). Patients with and without visible MR imaging pathology, typically punctate foci of suspected shearing injury, were indistinguishable in both atrophy and WBNAA. CONCLUSION: WBNAA detected neuronal/axonal injury beyond the minimal focal MR-visible lesions in mTBI. Combined with GM atrophy, the findings may provide further, noninvasive insight into the nature and progression of mTBI
— id: 73233, year: 2007, vol: 28, page: 907, stat: Journal Article,

Imaging and CSF studies in the preclinical diagnosis of Alzheimer's disease
de Leon, M J; Mosconi, L; Blennow, K; DeSanti, S; Zinkowski, R; Mehta, P D; Pratico, D; Tsui, W; Saint Louis, L A; Sobanska, L; Brys, M; Li, Y; Rich, K; Rinne, J; Rusinek, H
2007 Feb;1097:114-145, Annals of the New York Academy of Sciences
It is widely believed that the path to early and effective treatment for Alzheimer's disease (AD) requires the development of early diagnostic markers that are both sensitive and specific. To this aim, using longitudinal study designs, we and others have examined magnetic resonance imaging (MRI), 2-fluoro-2-deoxy-d-glucose-positron emission tomography (FDG/PET), and cerebrospinal fluid (CSF) biomarkers in cognitively normal elderly (NL) subjects and in patients with mild cognitive impairment (MCI). Such investigations have led to the often replicated findings that structural evidence of hippocampal atrophy as determined by MRI, as well as metabolic evidence from FDG-PET scan of hippocampal damage, predicts the conversion from MCI to AD. In this article we present a growing body of evidence of even earlier diagnosis. Brain pathology can be detected in NL subjects and used to predict future transition to MCI. This prediction is enabled by examinations revealing reduced glucose metabolism in the hippocampal formation (hippocampus and entorhinal cortex [EC]) as well as by the rate of medial temporal lobe atrophy as determined by MRI. However, neither regional atrophy nor glucose metabolism reductions are specific for AD. These measures provide secondary not primary evidence for AD. Consequently, we will also summarize recent efforts to improve the diagnostic specificity by combining imaging with CSF biomarkers and most recently by evaluating amyloid imaging using PET. We conclude that the combined use of conventional imaging, that is MRI or FDG-PET, with selected CSF biomarkers incrementally contributes to the early and specific diagnosis of AD. Moreover, selected combinations of imaging and CSF biomarkers measures are of importance in monitoring the course of AD and thus relevant to evaluating clinical trials
— id: 71870, year: 2007, vol: 1097, page: 114, stat: Journal Article,

Imaging and CSF studies in the preclinical diagnosis of Alzheimer's disease
de Leon, M. J; Mosconi, L; Blennow, K; DeSanti, S; Zinkowski, R; Mehta, P. D; Pratico, D; Tsui, W; Saint Louis, L. A; Sobanska, L; Brys, M; Li, Y; Rich, K; Rinne, J; Rusinek, H
Imaging and the aging brain Malden, MA, US: Blackwell Publishing, 2007,
(from the chapter) It is widely believed that the path to early and effective treatment for Alzheimer's disease (AD) requires the development of early diagnostic markers that are both sensitive and specific. To this aim, using longitudinal study designs, we and others have examined magnetic resonance imaging (MRI), 2-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG/PET), and cerebrospinal fluid (CSF) biomarkers in cognitively normal elderly (NL) subjects and in patients with mild cognitive impairment (MCI). Such investigations have led to the often replicated findings that structural evidence of hippocampal atrophy as determined by MRI, as well as metabolic evidence from FDG-PET scan of hippocampal damage, predicts the conversion from MCI to AD. In this article we present a growing body of evidence of even earlier diagnosis. Brain pathology can be detected in NL subjects and used to predict future transition to MCI. This prediction is enabled by examinations revealing reduced glucose metabolism in the hippocampal formation (hippocampus and entorhinal cortex [EC]) as well as by the rate of medial temporal lobe atrophy as determined by MRI. However, neither regional atrophy nor glucose metabolism reductions are specific for AD. These measures provide secondary not primary evidence for AD. Consequently, we will also summarize recent efforts to improve the diagnostic specificity by combining imaging with CSF biomarkers and most recently by evaluating amyloid imaging using PET. We conclude that the combined use of conventional imaging, that is MRI or FDG-PET, with selected CSF biomarkers incrementally contributes to the early and specific diagnosis of AD. Moreover, selected combinations of imaging and CSF biomarkers measures are of importance in monitoring the course of AD and thus relevant to evaluating clinical trials.
— id: 4482, year: 2007, vol: , page: 114, stat: Chapter,

What causes diminished corticomedullary differentiation in renal insufficiency?
Lee, Vivian S; Kaur, Manmeen; Bokacheva, Louisa; Chen, Qun; Rusinek, Henry; Thakur, Ravi; Moses, Daniel; Nazzaro, Carol; Kramer, Elissa L
2007 Apr;25(4):790-795, Journal of magnetic resonance imaging
PURPOSE: To investigate whether the loss of corticomedullary differentiation (CMD) on T1-weighted MR images due to renal insufficiency can be attributed to changes in T1 values of the cortex, medulla, or both. MATERIALS AND METHODS: Study subjects included 10 patients (serum creatinine range 0.6-3.0 mg/dL) referred for suspected renovascular disease who underwent 99mTc-diethylene triamine pentaacetic acid (DTPA) renography to determine single kidney glomerular filtration rate (SKGFR) and same-day MRI, which included T1 measurements and unenhanced T1-weighted gradient echo imaging. Corticomedullary differentiation on T1-weighted images was assessed qualitatively and quantitatively. RESULTS: SKGFR values ranged from 3.5 to 89.4 mL/minute based on radionuclide studies. T1 relaxation times of the medulla exceeded those of renal cortex by 147.9+/-176.0 msec (mean+/-standard deviation [SD]). Regression analysis showed a negative correlation between cortex T1 and SKGFR (r=-0.5; P=0.03), whereas there was no significant correlation between medullary T1 and SKGFR. The difference between medullary and cortical T1s correlated significantly with SKGFR (r=0.58; P<0.01). In all five kidneys with a corticomedullary contrast-to-noise ratio (CNR)<5.0 on T1-weighted images, SKGFR was less than 20 mL/minute. CONCLUSION: In our subject population, loss of CMD with decreasing SKGFR can be attributed primarily to an increased T1 relaxation time of the cortex. Medullary T1 values vary but do not appear to correlate with degree of renal insufficiency.
— id: 72810, year: 2007, vol: 25, page: 790, stat: Journal Article,

Renal function measurements from MR renography and a simplified multicompartmental model
Lee, Vivian S; Rusinek, Henry; Bokacheva, Louisa; Huang, Ambrose J; Oesingmann, Niels; Chen, Qun; Kaur, Manmeen; Prince, Keyma; Song, Ting; Kramer, Elissa L; Leonard, Edward F
2007 May;292(5):F1548-F1559, American journal of physiology. Renal physiology
The purpose of this study was to determine the accuracy and sources of error in estimating single-kidney glomerular filtration rate (GFR) derived from low-dose gadolinium-enhanced T1-weighted MR renography. To analyze imaging data, MR signal intensity curves were converted to concentration vs. time curves, and a three-compartment, six-parameter model of the vascular-nephron system was used to analyze measured aortic, cortical, and medullary enhancement curves. Reliability of the parameter estimates was evaluated by sensitivity analysis and by Monte Carlo analyses of model solutions to which random noise had been added. The dominant sensitivity of the medullary enhancement curve to GFR 1-4 min after tracer injection was supported by a low coefficient of variation in model-fit GFR values (4%) when measured data were subjected to 5% noise. These analyses also showed the minimal effects of bolus dispersion in the aorta on parameter reliability. Single-kidney GFR from MR renography analyzed by the three-compartment model (4.0-71.4 ml/min) agreed well with reference measurements from (99m)Tc-DTPA clearance and scintigraphy (r = 0.84, P < 0.001). Bland-Altman analysis showed an average difference of 11.9 ml/min (95% confidence interval = 5.8-17.9 ml/min) between model and reference values. We conclude that a nephron-based multicompartmental model can be used to derive clinically useful estimates of single-kidney GFR from low-dose MR renography.
— id: 72965, year: 2007, vol: 292, page: F1548, stat: Journal Article,

Early detection of Alzheimer's disease using neuroimaging
Mosconi, Lisa; Brys, Miroslaw; Glodzik-Sobanska, Lidia; De Santi, Susan; Rusinek, Henry; de Leon, Mony J
2007 Jan-Feb;42(1-2):129-138, Experimental gerontology
Neuroimaging is being increasingly used to complement clinical assessments in the early detection of Alzheimer's disease (AD). Structural magnetic resonance imaging (MRI) and metabolic positron emission tomography (FDG-PET) are the most clinically used and promising modalities to detect brain abnormalities in individuals who might be at risk for AD but who have not yet developed symptoms. The knowledge of established risk factors for AD enabled investigators to develop enrichment strategies for longitudinal imaging studies to reduce the sample sizes and study duration. The present review focuses on the results obtained by MRI and FDG-PET studies that examined the preclinical AD stages in several at risk populations: (1) individuals from families with autosomal dominant early-onset AD (FAD), (2) patients with mild cognitive impairment (MCI), particularly in memory, who are at very high risk for declining to AD with an estimated decline rate of 10-30% per year, (3) normal young and middle-age subjects carriers of known susceptibility genes for late-onset AD such as the Apolipoprotein E (ApoE) E4 allele, and (4) as age is the main risk factor for AD, normal elderly individuals followed to the onset of MCI and AD. Overall, these studies show that the use of imaging for the early detection of AD is successful even in the earlier stages of disease when clinical symptoms are not fully expressed and the regional brain damage may be limited
— id: 70031, year: 2007, vol: 42, page: 129, stat: Journal Article,

Quantitation, regional vulnerability, and kinetic modeling of brain glucose metabolism in mild Alzheimer's disease
Mosconi, Lisa; Tsui, Wai H; Rusinek, Henry; De Santi, Susan; Li, Yi; Wang, Gene-Jack; Pupi, Alberto; Fowler, Joanna; de Leon, Mony J
2007 Sep;34(9):1467-1479, European journal of nuclear medicine & molecular imaging
PURPOSE: To examine CMRglc measures and corresponding glucose transport (K (1) and k (2)) and phosphorylation (k (3)) rates in the medial temporal lobe (MTL, comprising the hippocampus and amygdala) and posterior cingulate cortex (PCC) in mild Alzheimer's disease (AD). METHODS: Dynamic FDG PET with arterial blood sampling was performed in seven mild AD patients (age 68 +/- 8 years, four females, median MMSE 23) and six normal (NL) elderly (age 69 +/- 9 years, three females, median MMSE 30). Absolute CMRglc (mumol/100 g/min) was calculated from MRI-defined regions of interest using multiparametric analysis with individually fitted kinetic rate constants, Gjedde-Patlak plot, and Sokoloff's autoradiographic method with population-based rate constants. Relative ROI/pons CMRglc (unitless) was also examined. RESULTS: With all methods, AD patients showed significant CMRglc reductions in the hippocampus and PCC, and a trend towards reduced parietotemporal CMRglc, as compared with NL. Significant k (3) reductions were found in the hippocampus, PCC and amygdala. K (1) reductions were restricted to the hippocampus. Relative CMRglc had the largest effect sizes in separating AD from NL. However, the magnitude of CMRglc reductions was 1.2- to 1.9-fold greater with absolute than with relative measures. CONCLUSION: CMRglc reductions are most prominent in the MTL and PCC in mild AD, as detected with both absolute and relative CMRglc measures. Results are discussed in terms of clinical and pharmaceutical applicability
— id: 71229, year: 2007, vol: 34, page: 1467, stat: Journal Article,

Benefit of CT venography for the diagnosis of thromboembolic disease
Rhee, Kyung Hwa; Iyer, Ramesh S; Cha, Susan; Naidich, David P; Rusinek, Henry; Jacobowitz, Glenn R; Ko, Jane P
2007 Jul-Aug;31(4):253-258, Clinical imaging
OBJECTIVE: The aim of this study was to determine the benefit of lower extremity CT venography (CTV) with pulmonary CT angiography (CTA) for diagnosing thromboembolic (TE) disease. SUBJECTS AND METHODS: Reports of all CTAs and CTVs over a 3-year interval (Group I) and CTAs, CTVs, and lower extremity Doppler ultrasounds (US) over a 1 1/2-year subset (Group II) were reviewed. Patient population was inpatients and emergency department patients who were assessed for pulmonary embolism (PE) and deep venous thrombosis (DVT) at a tertiary care hospital. Reported results for CTA or CTV were categorized as positive (CTA(P), CTV(P)), negative (CTA(N), CTV(N)), or indeterminate for PE or DVT. When CTV and US results were discrepant, medical records were reviewed for clinical management. Additional benefit of CTV was assessed by chi-square analysis. RESULTS: In Group I, 737 (81.1%) of 909 CTAs from combined CTA/CTV studies were negative. The diagnosis rate of TE disease increased from 13.0% to 17.3% with the addition of CTV(P)s (P=.01). Of the 119 cases in Group II undergoing combined CTA, CTV, and US, CTV and US were both positive in eight and both negative in 88. Of the seven discordant CTVs and USs with clinical follow-up, five CTVs were positive while USs were negative, three of which were treated clinically for TE disease, while two were considered falsely positive. As CTA also proved positive in one of the three, CTV therefore affected management in two of these five cases and increased the rate of thromboembolism diagnosis from 21.0% to 22.6%; however, this was not significant (P>.05). Two CTV(N)s were managed as false negatives. CONCLUSIONS: The combined use of CTA and CTV significantly increases the rate of TE disease over CTA alone. In cases in which ultrasound is performed, however, there is no significant advantage to performing combined CTA/CTV studies
— id: 73253, year: 2007, vol: 31, page: 253, stat: Journal Article,

Performance of an automated segmentation algorithm for 3D MR renography
Rusinek, Henry; Boykov, Yuri; Kaur, Manmeen; Wong, Samson; Bokacheva, Louisa; Sajous, Jan B; Huang, Ambrose J; Heller, Samantha; Lee, Vivian S
2007 Jun;57(6):1159-1167, Magnetic resonance in medicine
The accuracy and precision of an automated graph-cuts (GC) segmentation technique for dynamic contrast-enhanced (DCE) 3D MR renography (MRR) was analyzed using 18 simulated and 22 clinical datasets. For clinical data, the error was 7.2 +/- 6.1 cm(3) for the cortex and 6.5 +/- 4.6 cm(3) for the medulla. The precision of segmentation was 7.1 +/- 4.2 cm(3) for the cortex and 7.2 +/- 2.4 cm(3) for the medulla. Compartmental modeling of kidney function in 22 kidneys yielded a renal plasma flow (RPF) error of 7.5% +/- 4.5% and single-kidney GFR error of 13.5% +/- 8.8%. The precision was 9.7% +/- 6.4% for RPF and 14.8% +/- 11.9% for GFR. It took 21 min to segment one kidney using GC, compared to 2.5 hr for manual segmentation. The accuracy and precision in RPF and GFR appear acceptable for clinical use. With expedited image processing, DCE 3D MRR has the potential to expand our knowledge of renal function in individual kidneys and to help diagnose renal insufficiency in a safe and noninvasive manner
— id: 73254, year: 2007, vol: 57, page: 1159, stat: Journal Article,

Methodology of pole piece design in permanent magnets
Abele, MG; Tsui, W; Rusinek, H
2006 APR 15 ;99(8):138-140, Journal of applied physics
Magnet shimming methodology is important for achieving the stringent field uniformity required for magnetic-resonance imaging. Shimming is necessary to correct for design limitations and to compensate for magnet magnetization and fabrication tolerances. An exact theory of the shimming procedure is presented, based on the cylindrical harmonic expansion of the magnetostatic potential within the imaging region. Cancellation of the harmonics is achieved by modulating the magnetostatic potential at the parallel interfaces between the pole pieces and the cavity. This spatial filtering is implemented in two complementary ways. An active filter is generated by distributing magnetized material on the pole piece surfaces. An independent, passive filter solution is achieved by deriving the geometric profile of the pole piece from an image dipole distribution inside a ferromagnetic body. Both active and passive methodologies are demonstrated on an example of a recently introduced conical permanent magnet. (C) 2006 American Institute of Physics
— id: 64272, year: 2006, vol: 99, page: 138, stat: Journal Article,

Single breath-hold T1 measurement using low flip angle TrueFISP
Bokacheva, L; Huang, A J; Chen, Q; Oesingmann, N; Storey, P; Rusinek, H; Lee, V S
2006 May;55(5):1186-1190, Magnetic resonance in medicine
A method for estimating T1 using a single breath-hold, segmented, inversion recovery prepared, true fast imaging with steady-state precession (sIR-TrueFISP) acquisition at low flip angle (FA) was implemented in this study. T1 values measured by sIR-TrueFISP technique in a Gd-DTPA-doped water phantom and the human brain and abdomen of healthy volunteers were compared with the results of the standard IR fast spin echo (FSE) technique. A good correlation between the two methods was observed (R2=0.999 in the phantom, and R2=0.943 in the brain and abdominal tissues). The T1 values of the tissues agreed well with published results. sIR-TrueFISP enables fast measurements of T1 to be obtained within a single breath-hold with good accuracy, which is particularly important for chest and abdominal imaging
— id: 68771, year: 2006, vol: 55, page: 1186, stat: Journal Article,

Longitudinal CSF and MRI biomarkers improve the diagnosis of mild cognitive impairment
de Leon, M J; DeSanti, S; Zinkowski, R; Mehta, P D; Pratico, D; Segal, S; Rusinek, H; Li, J; Tsui, W; Saint Louis, L A; Clark, C M; Tarshish, C; Li, Y; Lair, L; Javier, E; Rich, K; Lesbre, P; Mosconi, L; Reisberg, B; Sadowski, M; DeBernadis, J F; Kerkman, D J; Hampel, H; Wahlund, L-O; Davies, P
2006 Mar;27(3):394-401, Neurobiology of aging
The diagnosis of Alzheimer's disease (AD) in patients with mild cognitive impairment (MCI) is limited because it is based on non-specific behavioral and neuroimaging findings. The lesions of Alzheimer's disease: amyloid beta (Abeta) deposits, tau pathology and cellular oxidative damage, affect the hippocampus in the earlier stages causing memory impairment. In a 2-year longitudinal study of MCI patients and normal controls, we examined the hypothesis that cerebrospinal fluid (CSF) markers for these pathological features improve the diagnostic accuracy over memory and magnetic resonance imaging (MRI)-hippocampal volume evaluations. Relative to control, MCI patients showed decreased memory and hippocampal volumes and elevated CSF levels of hyperphosphorylated tau and isoprostane. These two CSF measures consistently improved the diagnostic accuracy over the memory measures and the isoprostane measure incremented the accuracy of the hippocampal volume achieving overall diagnostic accuracies of about 90%. Among MCI patients, over 2 years, longitudinal hippocampal volume losses were closely associated with increasing hyperphosphorylated tau and decreasing amyloid beta-42 levels. These results demonstrate that CSF biomarkers for AD contribute to the characterization of MCI
— id: 62680, year: 2006, vol: 27, page: 394, stat: Journal Article,

Clinical significance of dilated Virchow-Robin spaces in mild traumatic brain injury
Inglese, Matilde; Grossman, Robert I; Diller, Leonard; Babb, James S; Gonen, Oded; Silver, Jonathan M A; Rusinek, Henry
2006 Jan;20(1):15-21, Brain injury
PRIMARY OBJECTIVE: To investigate the relationship between the number of dilated Virchow-Robin spaces (VRS) and neurocognitive findings in patients with traumatic brain injury (TBI). RESEARCH DESIGN: Thirty-eight patients with TBI and 21 controls were studied. METHODS AND PROCEDURES: Fifteen patients underwent MRI within a mean interval of 5.4 (range 1-12) days from the brain injury and 23 after an average period of 5.5 (range 0.2-31) years. All subjects were examined with a battery of 13 neuropsychological tests (NP). MAIN OUTCOMES AND RESULTS: The average number of VRS was significantly higher in patients than in controls. There were no significant differences between patients and controls in terms of NP tests. The number of VRS showed a significant inverse correlation with processing speed and a positive correlation with visual perceptual of attention only in patients studied within a short delay of trauma. CONCLUSIONS: VRS are not directly associated to neurocognitive findings, suggesting that they may represent a result of the shear-strain injury
— id: 66693, year: 2006, vol: 20, page: 15, stat: Journal Article,

Effect of blood vessels on measurement of nodule volume in a chest phantom
Ko, Jane P; Marcus, Rachel; Bomsztyk, Elan; Babb, James S; Stefanescu, Cornel; Kaur, Manmeen; Naidich, David P; Rusinek, Henry
2006 Apr;239(1):79-85, Radiology
PURPOSE: To identify, by using a chest phantom, whether vessels that contact lung nodules measuring less than 5 mm in diameter will affect nodule volume assessment. MATERIALS AND METHODS: Forty synthetic nodules (20 with ground-glass attenuation and 20 with solid attenuation) that measured less than 5 mm in diameter were placed into a chest phantom either adjacent to (n = 30) or isolated from (n = 10) synthetic vessels. Nodules were imaged by using low-dose (20 mAs) and diagnostic (120 mAs) multi-detector row computed tomography (CT). Nodules that were known to lie in direct contact with vessels were confirmed by visual inspection. Nontargeted 1.25 x 1.00-mm sections were analyzed with a three-dimensional computer-assisted method for measuring nodule volume. A mixed-model analysis of variance was used to examine the influence of several factors (eg, the presence of adjacent vessels; tube current-time product; and nodule attenuation, diameter, and location) on measurement error. RESULTS: The mean absolute error (MAE) for all nodules adjacent to vessels was 2.3 mm(3), which was higher than the MAE for isolated nodules (1.9 mm(3)) (P < .001). This difference proved significant only for diagnostic CT (2.2 mm(3) for nodules adjacent to vessels vs 1.3 mm(3) for nodules isolated from vessels) (P < .05). A larger MAE was noted for nodules with ground-glass attenuation (2.3 mm(3)) versus those with solid attenuation (2.0 mm(3)), for increasing nodule volume (1.66 mm(3) for nodules smaller than 20 mm(3) vs 2.83 mm(3) for nodules larger than 40 mm(3)), and for posterior nodule location (P < .05). CONCLUSION: The presence of a vessel led to a small yet significant increase in volume error on diagnostic-quality images. This represents less than one-third of the overall error, even for nodules larger than 40 mm(3) or approximately 4 mm in diameter. This increase, however, may be more important for smaller nodules with errors of less than 3 mm(3)
— id: 64205, year: 2006, vol: 239, page: 79, stat: Journal Article,

Dose-related nephrotoxicity
Rosovsky, Mark; Rusinek, Henry
2006 Aug;240(2):614-614, Radiology
— id: 73258, year: 2006, vol: 240, page: 614, stat: Journal Article,

Four dimensional MR image analysis of dynamic renography
Song, Ting; Lee, Vivian S; Rusinek, Henry; Wong, Samson; Laine, Andrew F
2006 ;1:3134-3137, Conference Proceedings (IEEE Engineering in Medicine & Biology Society)
A novel four dimensional image analysis approach including registration and segmentation of dynamic contrast enhanced renal MR images is presented. This integrated method is motivated by the observation of the reciprocity between registration and segmentation in 4D time-series images. Fully automated Fourier-based registration with sub-voxel accuracy and semi-automated time-series segmentation were intertwined to improve the accuracy in a multi-step fashion. We have tested our algorithm on several real patient data sets. Clinical validation showed remarkable and consistent agreement between the proposed method and manual segmentation by experts
— id: 96684, year: 2006, vol: 1, page: 3134, stat: Journal Article,

Integrated four dimensional registration and segmentation of dynamic renal MR images
Song, Ting; Lee, Vivian S; Rusinek, Henry; Wong, Samson; Laine, Andrew F
2006 ;9(Pt 2):758-765, Lecture notes in computer science
In this paper a novel approach for the registration and segmentation of dynamic contrast enhanced renal MR images is presented. This integrated method is motivated by the observation of the reciprocity between registration and segmentation in 4D time-series images. Fully automated Fourier-based registration with sub-voxel accuracy and semi-automated time-series segmentation were intertwined to improve the accuracy in a multi-step fashion. We have tested our algorithm on several real patient data sets. Clinical validation showed remarkable and consistent agreement between the proposed method and manual segmentation by experts
— id: 73256, year: 2006, vol: 9, page: 758, stat: Journal Article,

Assessing global invasion of newly diagnosed glial tumors with whole-brain proton MR spectroscopy
Cohen, Benjamin A; Knopp, Edmond A; Rusinek, Henry; Babb, James S; Zagzag, David; Gonen, Oded
2005 Oct;26(9):2170-2177, AJNR. American journal of neuroradiology
BACKGROUND AND PURPOSE: Because of their invasive nature, high-grade glial tumors are uniformly fatal. The purpose of this study was to quantify MR imaging-occult, glial tumor infiltration beyond its radiologic margin through its consequent neuronal cell damage, assessed by the global concentration decline of the neuronal marker N-acetylaspartate (NAA). METHODS: Seventeen patients (10 men; median age, 39 years; age range, 23-79 years) with radiologically suspected (later pathologically confirmed) supratentorial glial neoplasms, and 17 age- and sex-matched controls were studied. Their whole-brain NAA (WBNAA) amounts were obtained with proton MR spectroscopy: for patients on the day of surgery (n = 17), 1 day postsurgery (n = 15), and once for each control. To convert into concentrations, suitable for intersubject comparison, patients' global NAA amounts were divided by their brain volumes segmented from MR imaging. Least squares regression was used to analyze the data. RESULTS: Pre- and postoperative WBNAA (mean +/- SD) of 9.2 +/- 2.1 and 9.7 +/- 1.8 mmol/L, respectively, in patients were indistinguishable (P = .369) but significantly lower than in controls (12.5 +/- 1.4 mmol/L). Mean resected tumor size (n = 15) was approximately 3% of total brain volume. CONCLUSION: The average 26% WBNAA deficit in the patients, which persisted following surgical resection, cannot be explained merely by depletion within the approximately 3% MR imaging-visible tumor volume or an age-dependent effect. Although there could be several possible causes of such widespread decline--perineuronal satellitosis, neuronal deafferentation, Wallerian and retrograde degeneration, vasogenic edema, functional diaschisis, secondary vascular changes--most are a direct or indirect reflection of extensive, MR imaging-occult, microscopic tumor cell infiltration, diffusely throughout the otherwise 'normal-appearing' brain
— id: 61241, year: 2005, vol: 26, page: 2170, stat: Journal Article,

Brain compression without global neuronal loss in meningiomas: whole-brain proton MR spectroscopy report of 2 cases
Cohen, Benjamin A; Knopp, Edmond A; Rusinek, Henry; Liu, Songtao; Gonen, Oded
2005 Oct;26(9):2178-2182, AJNR. American journal of neuroradiology
We report the findings from whole-brain proton MR spectroscopy, quantifying the neuronal marker N-acetylaspartate (NAA), for 2 presurgical meningioma patients and 10 healthy controls. The patients' whole-brain NAA (WBNAA) concentrations were considerably elevated (3+ SDs) compared with healthy controls when excluding the tumors from brain volume; WBNAA levels normalized following correction to approximate 'preneoplastic' brain size. These results suggest global neuronal preservation in these 2 patients while their brains were compressed by large, slowly growing, extra-axial masses
— id: 61240, year: 2005, vol: 26, page: 2178, stat: Journal Article,

CSF biomarkers add to delayed recall and hippocampal volume in diagnosing MCI
De Leon, MJ; DeSanti, S; Zinkowski, R; Mehta, PD; Pratico, D; Rusinek, H; Li, J; Tsui, W; Reisberg, B; Zhan, J; Rich, K; Davies, P
2005 DEC ;30(53):S17-S17, Neuropsychopharmacology
— id: 59555, year: 2005, vol: 30, page: S17, stat: Journal Article,

Appendicitis in children: low-dose CT with a phantom-based simulation technique--initial observations
Fefferman, Nancy R; Bomsztyk, Elan; Yim, Angela M; Rivera, Rafael; Amodio, John B; Pinkney, Lynne P; Strubel, Naomi A; Noz, Marilyn E; Rusinek, Henry
2005 Nov;237(2):641-646, Radiology
PURPOSE: To retrospectively determine the accuracy of low-dose (20-mAs) computed tomography (CT) in the diagnosis of acute appendicitis in children by using a technique that enables the simulation of human CT scans acquired at a lower tube current given the image acquired at a standard dose. MATERIALS AND METHODS: Institutional review board approval was obtained, informed consent was not required, and the study was HIPAA compliant. The authors reviewed 100 standard-dose pediatric abdominal-pelvic CT scans (50 positive and 50 negative scans) obtained in 100 patients and corresponding simulated low-dose (20-mAs) scans. The standard-dose scans were obtained for evaluation in patients suspected of having appendicitis. Scans were reviewed in randomized order by four experienced pediatric radiologists. The patients with positive findings included 21 girls (mean age, 9.2 years) and 29 boys (mean age, 8.4 years). The patients with negative findings included 28 girls (mean age, 9.2 years) and 22 boys (mean age, 8.4 years). Simulation was achieved by adding noise patterns from repeated 20-mAs scans of a pediatric pelvis phantom to the original scans obtained with a standard tube current. Observers recorded their confidence in the diagnosis of appendicitis by using a six-point scale. Dose-related changes were analyzed with generalized estimating equations and the nonparametric sign test. RESULTS: There was a statistically significant (P < .001, sign test) decrease in both sensitivity and accuracy with a lower tube current, from 91.5% with the original tube current to 77% with the lower tube current. A low dose was the only statistically significant (P < .001) risk factor for a false-negative result. The specificity was unchanged at 94% for both the images obtained with the original tube current and the simulated low-dose images. The overall accuracy decreased from 92% with the original dose to 86% with the low dose. CONCLUSION: Preliminary findings indicate that it is feasible to optimize the CT dose used to evaluate appendicitis in children by using phantom-based computer simulations
— id: 62345, year: 2005, vol: 237, page: 641, stat: Journal Article,

The role of quantitative structural imaging in the early diagnosis of Alzheimer's disease
Glodzik-Sobanska, Lidia; Rusinek, Henry; Mosconi, Lisa; Li, Yi; Zhan, Jiong; de Santi, Susan; Convit, Antonio; Rich, Kenneth; Brys, Miroslaw; de Leon, Mony J
2005 Nov;15(4):803-26, x, Neuroimaging clinics of North America
The goal of this article is to review the role of structural neuroimaging in the diagnosis of Alzheimer's disease (AD). We present relevant neuroanatomy, highlight progress in the domain of AD imaging, and review the clinical characteristics of the prodromal phase of AD. We describe the history of the diagnostic issue by examining at cross-section and longitudinally the differences between patients who have AD and normal controls. We also present how subsequent works applied these characteristic traits to the early detection of the prodromal disease and to prediction of future decline. The article delineates the differences between subjects who have mild cognitive impairment and AD, which illustrate the spreading of the pathology with disease progression. The last section describes problems encountered in the differential diagnosis
— id: 64158, year: 2005, vol: 15, page: 803, stat: Journal Article,

Dilated perivascular spaces: hallmarks of mild traumatic brain injury
Inglese, Matilde; Bomsztyk, Elan; Gonen, Oded; Mannon, Lois J; Grossman, Robert I; Rusinek, Henry
2005 Apr;26(4):719-724, AJNR. American journal of neuroradiology
BACKGROUND AND PURPOSE: Recent animal and human studies have shown an increased frequency of enlarged, high-convexity Virchow-Robin spaces (VRS) in several neurologic diseases, suggesting their role as neuroradiologic markers of inflammatory changes. The aim of this study was to determine the prevalence of high-convexity dilated VRS in mild traumatic brain injury (TBI). METHODS: T2-weighted, T1-weighted, fluid-attenuated inversion recovery, and T2*-weighted gradient-echo brain MR images were acquired in 24 patients with TBI (10 women, 14 men; mean age, 33.6; range, 18.1-50.8 years) and 17 age- and sex-matched healthy control subjects (nine women, eight men; mean age, 32.8; range, 18.4-47.8 years). The mean interval after TBI was 3.6 days (range, 1-9 days) in 15 patients and 3.7 years (range, 0.6-13.4 years) in nine patients. Axial T2-weighted images were used to identify dilated VRS and to measure CSF volume; T1-weighted images were used to measure brain volume. Dilated VRS were identified as punctuate areas with CSF-like signal intensity in the high-convexity white matter. RESULTS: Mean (+/- standard deviation) number of VRS was significantly higher in patients (7.1 +/- 4.6) than in controls (2.4 +/- 2.9, P < .0003). In controls, VRS were associated with age (R = 0.69, P < .001) whereas in patients, they neither correlated with brain and CSF volumes nor with age and the elapsed time from injury. CONCLUSION: Our results suggest that the increased number of dilated VRS is a radiologic marker of mild head injury that is readily detectable on T2-weighted images. Because their number does not vary with time from injury, VRS probably reflect early and permanent brain changes
— id: 56042, year: 2005, vol: 26, page: 719, stat: Journal Article,

Effect of CT image compression on computer-assisted lung nodule volume measurement
Ko, Jane P; Chang, Jeffrey; Bomsztyk, Elan; Babb, James S; Naidich, David P; Rusinek, Henry
2005 Oct;237(1):83-88, Radiology
PURPOSE: To evaluate the effect of two-dimensional wavelet-based computed tomographic (CT) image compression according to the Joint Photographic Experts Group (JPEG) 2000 standard on computer-assisted assessment of nodule volume. MATERIALS AND METHODS: This HIPAA-compliant study was approved by the research board at the authors' institution; patients' informed consent was not required. Fifty-one nodules in 23 patients (seven men, 16 women; mean age, 59 years; age range, 39-75 years) were selected on low-dose CT scans that were compressed to levels of 10:1, 20:1, 30:1, and 40:1 by using a two-dimensional JPEG 2000 wavelet-based image compression method. Nodules were classified according to size (< or = 5 mm or > 5 mm in diameter), location (central, peripheral, or abutting pleura or fissures), and attenuation (solid, calcified, or subsolid). Regions of interest were placed on the original images and transposed onto compressed images. Nodule volumes on original (noncompressed) and compressed images were measured by using a computer-assisted method. A mixed-model analysis of variance was conducted for statistical evaluation. RESULTS: Nodule volumes averaged 388.1 mm3 (range, 34-3474 mm3). There were three calcified, 33 solid noncalcified, and 15 subsolid nodules (13 with ground-glass attenuation). Average volume decreased with increasing compression level, to 383 mm3 (10:1), 370 mm3 (20:1), 360 mm3 (30:1), and 354 mm3 (40:1). No significant difference was identified between measurements obtained on original images and those compressed to a level of 10:1. Significant differences were noted, however, between original images and those compressed to a level of 20:1 or greater (P < .05). Compression level significantly interacted with nodule size, location, and attenuation (P < .001). The effect of compression was greater for nodules with ground-glass attenuation than for those with higher attenuation values. The difference in mean volumes between original images and those compressed to a level of 20:1 was 34.9 mm3 for nodules with ground-glass attenuation, compared with 8.3 mm3 for higher-attenuation nodules, a 4.2-fold difference. CONCLUSION: Nodule volumes measured on images compressed to a level of 20:1 differed significantly from those measured on noncompressed images, especially for nodules with ground-glass attenuation. This difference could affect the assessment of nodule change in size as measured with computer-assisted methods
— id: 58740, year: 2005, vol: 237, page: 83, stat: Journal Article,

Reduced hippocampal metabolism in MCI and AD: automated FDG-PET image analysis
Mosconi, L; Tsui, W-H; De Santi, S; Li, J; Rusinek, H; Convit, A; Li, Y; Boppana, Madhu; de Leon, M J
2005 Jun 14;64(11):1860-1867, Neurology
BACKGROUND: To facilitate image analysis, most recent 2-[18F]fluoro-2-deoxy-d-glucose PET (FDG-PET) studies of glucose metabolism (MRglc) have used automated voxel-based analysis (VBA) procedures but paradoxically none reports hippocampus MRglc reductions in mild cognitive impairment (MCI) or Alzheimer disease (AD). Only a few studies, those using regions of interest (ROIs), report hippocampal reductions. The authors created an automated and anatomically valid mask technique to sample the hippocampus on PET (HipMask). METHODS: Hippocampal ROIs drawn on the MRI of 48 subjects (20 healthy elderly [NL], 16 MCI, and 12 AD) were used to develop the HipMask. The HipMask technique was applied in an FDG-PET study of NL (n = 11), MCI (n = 13), and AD (n = 12), and compared to both MRI-guided ROIs and VBA methods. RESULTS: HipMask and ROI hippocampal sampling produced significant and equivalent MRglc reductions for contrasts between MCI and AD relative to NL. The VBA showed typical cortical effects but failed to show hippocampal MRglc reductions in either clinical group. Hippocampal MRglc was the only discriminator of NL vs MCI (78% accuracy) and added to the cortical MRglc in classifying NL vs AD and MCI vs AD. CONCLUSIONS: The new HipMask technique provides accurate and rapid assessment of the hippocampus on PET without the use of regions of interest. Hippocampal glucose metabolism reductions are found in both mild cognitive impairment and Alzheimer disease and contribute to their diagnostic classification. These results suggest re-examination of prior voxel-based analysis 2-[18F]fluoro-2-deoxy-d-glucose PET studies that failed to report hippocampal effects
— id: 61248, year: 2005, vol: 64, page: 1860, stat: Journal Article,

Perfusion imaging of the liver: current challenges and future goals
Pandharipande, Pari V; Krinsky, Glenn A; Rusinek, Henry; Lee, Vivian S
2005 Mar;234(3):661-673, Radiology
Improved therapeutic options for hepatocellular carcinoma and metastatic disease place greater demands on diagnostic and surveillance tests for liver disease. Existing diagnostic imaging techniques provide limited evaluation of tissue characteristics beyond morphology; perfusion imaging of the liver has potential to improve this shortcoming. The ability to resolve hepatic arterial and portal venous components of blood flow on a global and regional basis constitutes the primary goal of liver perfusion imaging. Earlier detection of primary and metastatic hepatic malignancies and cirrhosis may be possible on the basis of relative increases in hepatic arterial blood flow associated with these diseases. To date, liver flow scintigraphy and flow quantification at Doppler ultrasonography have focused on characterization of global abnormalities. Computed tomography (CT) and magnetic resonance (MR) imaging can provide regional and global parameters, a critical goal for tumor surveillance. Several challenges remain: reduced radiation doses associated with CT perfusion imaging, improved spatial and temporal resolution at MR imaging, accurate quantification of tissue contrast material at MR imaging, and validation of parameters obtained from fitting enhancement curves to biokinetic models, applicable to all perfusion methods. Continued progress in this new field of liver imaging may have profound implications for large patient groups at risk for liver disease
— id: 51097, year: 2005, vol: 234, page: 661, stat: Journal Article,

Automatic 4-D registration in dynamic MR renography based on over-complete dyadic wavelet and Fourier transforms
Song, Ting; Lee, Vivian S; Rusinek, Henry; Kaur, Manmeen; Laine, Andrew F
2005 ;8(Pt 2):205-213, Lecture notes in computer science
Dynamic contrast-enhanced 4-D MR renography has the potential for broad clinical applications, but suffers from respiratory motion that limits analysis and interpretation. Since each examination yields at least over 10-20 serial 3-D images of the abdomen, manual registration is prohibitively labor-intensive. Besides in-plane motion and translation, out-of-plane motion and rotation are observed in the image series. In this paper, a novel robust and automated technique for removing out-of-plane translation and rotation with sub-voxel accuracy in 4-D dynamic MR images is presented. The method was evaluated on simulated motion data derived directly from a clinical patient's data. The method was also tested on 24 clinical patient kidney data sets. Registration results were compared with a mutual information method, in which differences between manually co-registered time-intensity curves and tested time-intensity curves were compared. Evaluation results showed that our method agreed well with these ground truth data
— id: 73259, year: 2005, vol: 8, page: 205, stat: Journal Article,

Automatic 4-D Registration in Dynamic MR Renography
Song, Ting; Lee, Vivian; Rusinek, Henry; Kaur, Manmeen; Laine, Andrew
2005 ;3:3067-3070, Conference Proceedings (IEEE Engineering in Medicine & Biology Society)
Dynamic contrast-enhanced 4-D MR renography has the potential for broad clinical applications, but suffers from respiratory motion that limits analysis and interpretation. Since each examination yields at least over 10 - 20 serial 3-D images of the abdomen, manual registration is prohibitively labor-intensive. Besides in-plane motion and translation, out-of-plane motion and rotation are observed in the image series. In this paper, a novel robust and automated technique for removing out-of-plane translation and rotation with sub-voxel accuracy in 4-D dynamic MR images is presented. The method was evaluated on simulated motion data derived directly from a clinical patients data. The method was also tested on 24 clinical patient kidney data sets. Registration results were compared with a mutual information method, in which differences between manually co-registered time-intensity curves and tested time-intensity curves were compared. Evaluation results showed that our method agreed well with these ground truth data
— id: 73257, year: 2005, vol: 3, page: 3067, stat: Journal Article,

Permanent conical magnet for interventional magnetic resonance imaging
Abele, MG; Rusinek, H
2004 SEP ;40(5):3382-3386, IEEE transactions on magnetics
We describe an open structure of permanently magnetized material for interventional magnetic resonance imaging of the brain. We transformed the ideal magnet, contained between two coaxial cones, into a practical device by a series of geometrical steps that minimize field perturbations. By taking advantage of the quasi-linear demagnetization characteristics of rare-earth materials, we could analyze the structure with an exact mathematical model. The magnet, built of material of remanence 1.38 T, generates a field of 0.45 T within its central gap 30 cm wide. Our numerical computations show a remarkable 0.25% field uniformity in the imaging region. The large opening makes the conical magnet suitable for interventional and surgical imaging
— id: 46518, year: 2004, vol: 40, page: 3382, stat: Journal Article,

MRI and CSF studies in the early diagnosis of Alzheimer's disease
de Leon, M J; DeSanti, S; Zinkowski, R; Mehta, P D; Pratico, D; Segal, S; Clark, C; Kerkman, D; DeBernardis, J; Li, J; Lair, L; Reisberg, B; Tsui, W; Rusinek, H
2004 Sep;256(3):205-223, Journal of internal medicine
Abstract. de Leon MJ, DeSanti S, Zinkowski R, Mehta PD, Pratico D, Segal S, Clark C, Kerkman D, DeBernardis J, Li J, Lair L, Reisberg B, Tsui W, Rusinek H. (New York University School of Medicine, NY; Nathan Kline Institute, NY; Molecular Geriatrics, Vernon Hills, IL; Institute for Basic Research, NY; and University of Pennsylvania, PA; USA). MRI and CSF studies in the early diagnosis of Alzheimer's disease (Key Symposium). J Intern Med 2004; 256: 205-223.The main goal of our studies has been to use MRI, FDG-PET, and CSF biomarkers to identify in cognitively normal elderly (NL) subjects and in patients with mild cognitive impairment (MCI), the earliest clinically detectable evidence for brain changes due to Alzheimer's disease (AD). A second goal has been to describe the cross-sectional and longitudinal interrelationships amongst anatomical, CSF and cognition measures in these patient groups. It is now well known that MRI-determined hippocampal atrophy predicts the conversion from MCI to AD. In our summarized studies, we show that the conversion of NL subjects to MCI can also be predicted by reduced entorhinal cortex (EC) glucose metabolism, and by the rate of medial temporal lobe atrophy as determined by a semi-automated regional boundary shift analysis (BSA-R). However, whilst atrophy rates are predictive under research conditions, they are not specific for AD and cannot be used as primary evidence for AD. Consequently, we will also review our effort to improve the diagnostic specificity by evaluating the use of CSF biomarkers and to evaluate their performance in combination with neuroimaging. Neuropathology studies of normal ageing and MCI identify the hippocampal formation as an early locus of neuronal damage, tau protein pathology, elevated isoprostane levels, and deposition of amyloid beta 1-42 (Abeta42). Many CSF studies of MCI and AD report elevated T-tau levels (a marker of neuronal damage) and reduced Abeta42 levels (possibly due to increased plaque sequestration). However, CSF T-tau and Abeta42 level elevations may not be specific to AD. Elevated isoprostane levels are also reported in AD and MCI but these too are not specific for AD. Importantly, it has been recently observed that CSF levels of P-tau, tau hyperphosphorylated at threonine 231 (P-tau231) are uniquely elevated in AD and elevations found in MCI are useful in predicting the conversion to AD. In our current MCI studies, we are examining the hypothesis that elevations in P-tau231 are accurate and specific indicators of AD-related changes in brain and cognition. In cross-section and longitudinally, our results show that evaluations of the P-tau231 level are highly correlated with reductions in the MRI hippocampal volume and by using CSF and MRI measures together one improves the separation of NL and MCI. The data suggests that by combining MRI and CSF measures, an early (sensitive) and more specific diagnosis of AD is at hand. Numerous studies show that neither T-tau nor P-tauX (X refers to all hyper-phosphorylation site assays) levels are sensitive to the longitudinal progression of AD. The explanation for the failure to observe longitudinal changes is not known. One possibility is that brain-derived proteins are diluted in the CSF compartment. We recently used MRI to estimate ventricular CSF volume and demonstrated that an MRI-based adjustment for CSF volume dilution enables detection of a diagnostically useful longitudinal P-tau231 elevation. Curiously, our most recent data show that the CSF isoprostane level does show significant longitudinal elevations in MCI in the absence of dilution correction. In summary, we conclude that the combined use of MRI and CSF incrementally contributes to the early diagnosis of AD and to monitor the course of AD. The interim results also suggest that a panel of CSF biomarkers can provide measures both sensitive to longitudinal change as well as measures that lend specificity to the AD diagnosis
— id: 44525, year: 2004, vol: 256, page: 205, stat: Journal Article,

Atrophy rate in medial temporal lobe: A correlate of AD progression
Endo, Y; Rusinek, H; De Santi, S; Frid, D; Tsui, WH; Segal, S; Convit, AJ; de Leon, MJ
2004 JUL ;25(10):S377-S377, Neurobiology of aging
— id: 47735, year: 2004, vol: 25, page: S377, stat: Journal Article,

Functional renal MR imaging
Huang, Ambrose J; Lee, Vivian S; Rusinek, Henry
2004 Sep;12(3):469-86, vi, Magnetic resonance imaging clinics of North America
MR imaging is the only noninvasive test that may provide a complete picture of renal status with minimal risk to the patient, simultaneously improving diagnosis and lowering costs. This article reviews several MR renography techniques, including approaches for quantifying renal perfusion and glomerular filtration rate. Also discussed are clinical applications for the diagnosis and follow-up of renovascular disease, hydronephrosis,and renal transplant dysfunction. The article concludes with an overview of technical problems and challenges facing MR renography
— id: 46149, year: 2004, vol: 12, page: 469, stat: Journal Article,

Preservation of cortical metabolic function by donepezil in patients with mild to moderate Alzheimer's disease: A 24-week clinical trial with placebo control
Moeller, JR; Rusinek, H; Casanova, MF; Hoffman, JM; Tune, LM; Perdomo, C; Ieni, JR; Jewart, RD; Cooper, TB
2004 DEC ;29(4):S190-S191, Neuropsychopharmacology
— id: 73266, year: 2004, vol: 29, page: S190, stat: Journal Article,

Magnetic resonance and PET studies in the early diagnosis of Alzheimer's disease
Mosconi, Lisa; De Santi, Susan; Rusinek, Henry; Convit, Antonio; de Leon, Mony J
2004 Sep;4(5):831-849, Expert review of neurotherapeutics
The demographics of aging identify an immediate need for the early diagnosis and development of dementia prevention strategies. Recent neuropathological studies have pointed to the early involvement of the hippocampus and entorhinal cortex in the progression of Alzheimer's disease in the brain. In particular, these studies have implicated tau-related pathology as an important cause of neuronal death. In addition, there is a large body of evidence showing that beta-amyloid, which has a predilection for the neocortex, is also involved early in the course of the disease and may also have toxic effects on cells. In vivo cerebrospinal fluid studies have shown that markers for these brain changes have a diagnostic value for Alzheimer's disease and that some measures also provide diagnostic specificity for Alzheimer's disease. Structural and metabolic imaging studies demonstrate brain changes in impaired and at-risk individuals. While currently available magnetic resonance and positron emission tomography techniques are not by themselves specific for the pathologic features of Alzheimer's disease, there are patterns of change that have been useful for the early diagnosis. As such, both prediction and longitudinal imaging studies demonstrate a capacity to recognize abnormalities that relate to future Alzheimer's disease and most recently to future mild cognitive impairment. This review highlights cross-sectional, prediction, and longitudinal magnetic resonance and positron emission tomography imaging studies and attempts to put into perspective their utility for the early diagnosis of Alzheimer's disease, and for their utility to provide diagnostic specificity. It is concluded that there is considerable promise for an early and specific diagnosis for Alzheimer's disease by combining information from imaging and biomarker modalities
— id: 56016, year: 2004, vol: 4, page: 831, stat: Journal Article,

Assessment of vasculature using combined MRI and MR angiography
Roche, Kevin J; Rivera, Rafael; Argilla, Michael; Fefferman, Nancy R; Pinkney, Lynne P; Rusinek, Henry; Genieser, Nancy B
2004 Apr;182(4):861-866, American journal of roentgenology
OBJECTIVE: The purpose of this study was to compare combined cine gradient-recalled echo MRI and MR angiography with conventional angiography in the evaluation of the pulmonary vascular supply in patients with pulmonary atresia, ventricular septal defect, and major aortopulmonary collateral arteries. MATERIALS AND METHODS: Eleven patients who underwent both MRI and conventional angiography were retrospectively reviewed. Contiguous 2D cine gradient-recalled echo images (TR range/TE, 30-80/4.8; flip angle, 20 degrees or 30 degrees ) and 3D MR angiographic images (TR range/TE range, 3.8-5.0/1.3-2.0; acquisition time, 13-32 sec) using gadopentetate meglumine (0.1-0.2 mmol/kg) were obtained. The presence, size, and course of the pulmonary arteries (main, right, left) and major aortopulmonary collateral arteries (>/= 5 mm) were determined. Presence of minor collateral arteries (< 5 mm) was also noted. Results were compared with findings at conventional angiography. RESULTS: MRI showed all main (n = 4) and branch (n = 17) pulmonary arteries found at conventional angiography and showed the pulmonary confluence in five of six cases. MRI showed all major aortic collaterals (n = 22) with a highly significant correlation between MRI and conventional angiography measurements (r = 0.84, p < 0.001 [95% confidence interval, -0.35 to 0.40]). One coronary artery collateral was not shown on MRI examination. At MRI, 12 of 14 major and four of seven minor brachiocephalic artery collaterals were shown. MRI showed more minor aortic collaterals than angiography (22 vs 18 vessels, respectively). CONCLUSION: Combined cine gradient-recalled echo MRI and MR angiography is a reliable method for imaging pulmonary vascular supply in patients with these disorders. Additional prospective studies comparing MRI and conventional angiography may determine whether routine preoperative conventional angiography is required
— id: 43783, year: 2004, vol: 182, page: 861, stat: Journal Article,

Atrophy rate in medial temporal lobe during progression of Alzheimer disease
Rusinek, H; Endo, Y; De Santi, S; Frid, D; Tsui, W-H; Segal, S; Convit, A; de Leon, M J
2004 Dec 28;63(12):2354-2359, Neurology
OBJECTIVE: To establish the progression of brain atrophy rates in patients with a known date of onset of Alzheimer disease (AD). METHODS: Each of 18 subjects had two high-resolution T1-weighted three-dimensional MRI examinations. The two MRIs were coregistered and the annual rate of brain tissue atrophy was derived both for the entire brain and regionally for the left and right medial temporal lobe (MTL). Time since onset (TSO) of AD, defined as the interval between the date of onset and the midpoint of MRI dates, ranged from -2.9 to 4.2 years. RESULTS: In patients with AD, TSO was a correlate of the atrophy rate for both the left MTL (R2 = 0.58, p = 0.001) and right MTL (R2 = 0.30, p = 0.03). When serial measurements were applied to a control group of 21 cognitively normal elderly subjects, MTL atrophy rate classified the group membership (AD vs normal cognition) with an accuracy of 92.3%. CONCLUSION: Increased annual atrophy rate in the medial temporal lobe is a potential diagnostic marker of the progression of Alzheimer disease
— id: 57659, year: 2004, vol: 63, page: 2354, stat: Journal Article,

Renal magnetic resonance imaging
Rusinek, Henry; Kaur, Manmeen; Lee, Vivian S
2004 Nov;13(6):667-673, Current opinion in nephrology & hypertension
PURPOSE OF REVIEW: Current magnetic resonance imaging systems allow the visualization of normal and diseased kidney, with exquisite resolution of renal structures. Dynamic contrast magnetic resonance imaging has the potential, unique among all noninvasive modalities, to differentiate diseases that affect different portions of the vascular-nephron system. This article reviews the most important recently published studies in selected topics chosen because of their clinical relevance or potential for technical developments. RECENT FINDINGS: Magnetic resonance imaging is used increasingly to evaluate renal masses, the prenatal genitourinary system, urinary obstruction and infection, renal vasculature, and the kidneys of transplant donors and recipients. Dynamic contrast magnetic resonance renography based on gadolinium chelated to diethylenetriamine pentaacetic acid, a safe (non-nephrotoxic) paramagnetic agent, emerges as the functional renal imaging modality of choice. Both perfusion and filtration rates can be assessed in individual kidney. SUMMARY: Magnetic resonance imaging has the potential to provide a complete anatomic, physiologic, kidney-specific evaluation. With future advances in automated image analysis methods we can expect functional renal magnetic resonance imaging to play an influential role in management of renal disease
— id: 48998, year: 2004, vol: 13, page: 667, stat: Journal Article,

Automated assessment of small airway disease on lung CT : a preliminary study
Dittmer-Roche B; Rusinek H; Ko J; McGuiness C; Naidich D
2003 ;5030:41-50, Medical imaging (SPIE)
Air trapping is a prominent finding in small airway disease (SAD)of the lungs. To investigate the feasibility of accurate, automated assessment of air-trapping from low-dose CT, we compare visual scoring by expert radiologists to a conventional method of automated assessment as well as two novel methods. The conventional method,the markdensity maskmark method, has been reported to correlateweakly but significantly with visual scoring on normal-dose CT.While we were unable to reproduce these results on our low-dose scans, our two novel methods showed some promise. More study on larger data sets is required to determine the optimal analysis method.
— id: 44187, year: 2003, vol: 5030, page: 41, stat: Journal Article,

MR imaging of renal function
Huang, Ambrose J; Lee, Vivian S; Rusinek, Henry
2003 Sep;41(5):1001-1017, Radiologic clinics of North America
MR imaging is the only single noninvasive test that can potentially provide a complete picture of renal status with minimal risk to the patient, simultaneously improving diagnosis while lowering medical costs by virtue of its being a single test. The strengths of MR imaging lie in its high spatial and temporal resolution and its lack of exposure to ionizing radiation and nephrotoxic contrast agents. This article reviews the use of MR imaging for quantification of renal functional parameters and its application to clinical problems, such as RVD, hydronephrosis, and renal transplantation. Although advances in both the technical and clinical aspects of functional renal MR imaging have been made, much remains to be done. The preliminary results reported in the many studies reviewed are exciting, but these techniques need to be validated against accepted standards where such standards exist. In addition, and perhaps more important, the effects of these new diagnostic methods on patient outcomes must be studied. Finally, further progress in image processing and analysis must be made to make functional renal MR imaging truly practical. With these advances, one can expect functional renal MR imaging to play an ever-expanding and influential role in the care and management of the patient with renal disease
— id: 62354, year: 2003, vol: 41, page: 1001, stat: Journal Article,

Diffusely elevated cerebral choline and creatine in relapsing-remitting multiple sclerosis
Inglese, Matilde; Li, Belinda S Y; Rusinek, Henry; Babb, James S; Grossman, Robert I; Gonen, Oded
2003 Jul;50(1):190-195, Magnetic resonance in medicine
It is well known that multiple sclerosis (MS) pathogenesis continues even during periods of clinical silence. To quantify the metabolic characteristics of this activity we compared the absolute levels of N-acetylaspartate (NAA), creatine (Cr), and choline (Cho) in the normal-appearing white matter (NAWM) between relapsing-remitting (RR) MS patients and controls. Metabolite concentrations were obtained with 3D proton MR spectroscopy at 1.5 T in a 480 cm(3) volume-of-interest (VOI), centered on the corpus callosum of 11 MS patients and 9 matched controls. Gray/white-matter/cerebral-spinal-fluid (CSF) volumes were obtained from MRI segmentation. Patients' average VOI tissue volume (V(T)), 410.8 +/- 24.0 cm(3), and metabolite levels, NAA = 6.33 +/- 0.70, Cr = 4.67 +/- 0.52, Cho = 1.40 +/- 0.17 mM, were different from the controls by -8%, -9%, +22% and +32%. The Cho level was the only single metric differentiating patients from controls at 100% specificity and >90% sensitivity. Diffusely elevated Cho and Cr probably reflect widespread microscopic inflammation, gliosis, or de- and remyelination in the NAWM. Both metabolites are potential prognostic indicators of current disease activity, preceding NAA decline and atrophy
— id: 39190, year: 2003, vol: 50, page: 190, stat: Journal Article,

Small pulmonary nodules: volume measurement at chest CT--phantom study
Ko, Jane P; Rusinek, Henry; Jacobs, Erika L; Babb, James S; Betke, Margrit; McGuinness, Georgeann; Naidich, David P
2003 Sep;228(3):864-870, Radiology
Three-dimensional methods for quantifying pulmonary nodule volume at computed tomography (CT) and the effect of imaging variables were studied by using a realistic phantom. Two fixed-threshold methods, a partial-volume method (PVM) and a variable method, were used to calculate volumes of 40 plastic nodules (largest dimension, <5 mm: 20 nodules with solid attenuation and 20 with ground-glass attenuation) of known volume. Tube current times (20 and 120 mAs), reconstruction algorithms (high and low frequency), and nodule characteristics were studied. Higher precision was associated with use of a PVM with predetermined pure nodule attenuation, high-frequency algorithm, and diagnostic CT technique (120 mAs). A PVM is promising for volume quantification and follow-up of nodules
— id: 43798, year: 2003, vol: 228, page: 864, stat: Journal Article,

Wavelet compression of low-dose chest CT data: effect on lung nodule detection
Ko, Jane P; Rusinek, Henry; Naidich, David P; McGuinness, Georgeann; Rubinowitz, Ami N; Leitman, Barry S; Martino, Jennifer M
2003 Jul;228(1):70-75, Radiology
PURPOSE: To assess the effect of using a lossy Joint Photographic Experts Group standard for wavelet image compression, JPEG2000, on pulmonary nodule detection at low-dose computed tomography (CT). MATERIALS AND METHODS: One hundred sets of lung CT data ('cases') were compressed to 30:1, 20:1, and 10:1 levels by using a wavelet-based JPEG2000 method, resulting in 400 test cases. Each case consisted of nine 1.25-mm sections that had been obtained with 20-40 mAs. Four thoracic radiologists independently interpreted the test case images. Performance was measured by using area under the receiver operating characteristic (ROC) curve (Az) and conventional sensitivity and specificity analyses. RESULTS: There were 51 cases with and 49 without lung nodules. Az values were 0.984, 0.988, 0.972, 0.921, respectively, for original and 10:1, 20:1, and 30:1 compressed images. Az values decreased significantly at 30:1 (P =.014) but not at 10:1 compression, with a trend toward significant decrease at 20:1 (P =.051). Specificity values were unaffected by compression (>98.0% at all compression levels). Sensitivity values were 86.3% (176 of 204 test cases with nodules), 77.9% (159 of 204 cases), 76.5% (156 of 204 cases), and 70.1% (143 of 204 cases), respectively, for original and 10:1, 20:1, and 30:1 compressed images. Results of logistic regression model analysis confirmed the significant effects of compression rate and nodule attenuation, size, and location on sensitivity (P <.05). CONCLUSION: While no reduction in nodule detection at 10:1 compression levels was demonstrated by using ROC analysis, a significant decrease in sensitivity was identified. Further investigation is needed before widespread use of image compression technology in low-dose chest CT can be recommended
— id: 43799, year: 2003, vol: 228, page: 70, stat: Journal Article,

Dynamic three-dimensional MR renography for the measurement of single kidney function: initial experience
Lee, Vivian S; Rusinek, Henry; Noz, Marilyn E; Lee, Peter; Raghavan, Meera; Kramer, Elissa L
2003 Apr;227(1):289-294, Radiology
A three-dimensional magnetic resonance (MR) renographic method to measure single kidney glomerular filtration rate (GFR) and split renal function was developed that is based on renal signal intensity measurements during 2-3 minutes after intravenous injection of a low dose (2 mL or 0.01 mmol/kg) of gadopentetate dimeglumine. In nine subjects, single kidney MR GFR indices correlated well with technetium 99m (99mTc) diethylenetriaminepentaacetic acid (DTPA) clearance (r = 0.7-0.8) for GFR values of 7-48 mL/min. MR right kidney split renal function values (range, 32%-59%) also correlated well with 99mTc-DTPA radionuclide measurements (r = 0.76); differences between the two methods averaged 0.8% +/- 8. MR renography was performed along with contrast material-enhanced MR imaging of the kidneys and renal arteries and added 8 minutes or less to the total examination time
— id: 43821, year: 2003, vol: 227, page: 289, stat: Journal Article,

Regional brain atrophy rate predicts future cognitive decline: 6-year longitudinal MR imaging study of normal aging
Rusinek, Henry; De Santi, Susan; Frid, Dina; Tsui, Wai-Hon; Tarshish, Chaim Y; Convit, Antonio; de Leon, Mony J
2003 Dec;229(3):691-696, Radiology
PURPOSE: To determine if medial temporal lobe (MTL) atrophy rate, assessed by using an automated procedure over the initial time interval of a 6-year, three-time-point longitudinal study, is predictive of future memory decline. MATERIALS AND METHODS: Healthy elderly subjects (age, >60 years) were administered a comprehensive battery of neuropsychometric tests and underwent magnetic resonance (MR) imaging at baseline and two or more follow-up examinations. The rate of brain atrophy between the baseline and first follow-up examinations was assessed by using an automated procedure that included spatial coregistration of the two images and regional brain boundary shift analysis. At final observation, the 45 subjects were separated into a group of those who did and a group of those who did not show objective evidence of cognitive decline. A forward stepwise logistic regression model was used to identify variables that predicted decline. RESULTS: Thirty-two subjects remained healthy, and 13 showed cognitive decline. Among subjects who showed cognitive decline, six declined after the second observation. MTL atrophy rate, through its interactions with sex and age, was the most significant predictor of decline. The overall accuracy of prediction was 89% (in 40 of 45 subjects), with 91% specificity (in 29 of 32 subjects) and 85% sensitivity (in 11 of 13 subjects). CONCLUSION: Among healthy elderly individuals, increased MTL atrophy rate appears to be predictive of future memory decline
— id: 43857, year: 2003, vol: 229, page: 691, stat: Journal Article,

A neuropathology of psychosis?
Wolkin, Adam; Rusinek, Henry
2003 Jan 25;361(9354):270-271, Lancet
— id: 73260, year: 2003, vol: 361, page: 270, stat: Journal Article,

CT findings in acute gangrenous cholecystitis
Bennett, Genevieve L; Rusinek, Henry; Lisi, Virna; Israel, Gary M; Krinsky, Glenn A; Slywotzky, Chrystia M; Megibow, Alec
2002 Feb;178(2):275-281, American journal of roentgenology
OBJECTIVE: The purpose of this study was to determine the CT findings in acute gangrenous cholecystitis. MATERIALS AND METHODS: Four observers retrospectively reviewed CT scans in 75 patients (23 with acute gangrenous cholecystitis, 25 with acute non-gangrenous cholecystitis, and 27 without cholecystitis). The following findings were evaluated: distention, mural thickening, wall enhancement, irregular wall, wall striation, intraluminal membranes, pericholecystic inflammation, gallstones, pericholecystic fluid, enhancement of liver parenchyma, pericholecystic abscess, and gas in the wall or lumen. Sensitivity and specificity of CT for gangrenous cholecystitis and for each finding were calculated. Two reviewers in consensus measured gallbladder dimension and wall thickness. Logistic regression models were used to predict gangrenous versus non-gangrenous cholecystitis. RESULTS: Sensitivity, specificity, and accuracy of CT for acute cholecystitis were 91.7%, 99.1%, and 94.3%, respectively, and for acute gangrenous cholecystitis were 29.3%, 96.0%, and 64.1%, respectively. Findings with the highest specificity for gangrenous cholecystitis were gas in the wall or lumen (100%), intraluminal membranes (99.5%), irregular or absent wall (97.6%), and abscess (96.6%). The difference between the mean gallbladder wall thickness and the short-axis dimension for the two groups with cholecystitis was statistically significant. In three patients with gangrenous cholecystitis, no mural enhancement was seen. Pericholecystic fluid also achieved statistical significance for the diagnosis of gangrene. Multivariate logistic regression analysis showed that the overall accuracy of CT for gangrenous cholecystitis was 86.7%. CONCLUSION: CT findings most specific for acute gangrenous cholecystitis are gas in the wall or lumen, intraluminal membranes, irregular wall, and pericholecystic abscess. Gangrenous cholecystitis is associated with a lack of mural enhancement, pericholecystic fluid, and a greater degree of gallbladder distention and wall thickening
— id: 26484, year: 2002, vol: 178, page: 275, stat: Journal Article,

Longitudinal cerebrospinal fluid tau load increases in mild cognitive impairment
de Leon, M J; Segal, S; Tarshish, C Y; DeSanti, S; Zinkowski, R; Mehta, P D; Convit, A; Caraos, C; Rusinek, H; Tsui, W; Saint Louis, L A; DeBernardis, J; Kerkman, D; Qadri, F; Gary, A; Lesbre, P; Wisniewski, T; Poirier, J; Davies, P
2002 Nov 29;333(3):183-186, Neuroscience letters
Cross-sectional cerebrospinal fluid (CSF) levels of tau and amyloid (A) beta (beta) are of diagnostic importance for Alzheimer's disease (AD) and mild cognitive impairment (MCI). However, most longitudinal studies of tau fail to demonstrate progression. Because predominantly brain-derived proteins such as tau, have higher ventricle to lumbar ratios, we hypothesized that adjusting for the ventricular enlargement of AD would correct for the dilution of tau, and improve detection of longitudinal change. Abeta which is not exclusively brain derived, shows a ratio <1, and no benefit was expected from adjustment. In a 1 year longitudinal study of eight MCI and ten controls, we examined CSF levels of hyperphosphorylated (P) tau231, Abeta40, and Abeta42. In cross-section, MCI patients showed elevated Ptau231 and Abeta40 levels, and greater ventricular volumes. Longitudinally, only after adjusting for the ventricular volume and only for Ptau231, were increases seen in MCI. Further studies are warranted on mechanisms of tau clearance and on using imaging to interpret CSF studies
— id: 39372, year: 2002, vol: 333, page: 183, stat: Journal Article,

Computed tomography diagnosis utilizing compressed image data: an ROC analysis using acute appendicitis as a model
Megibow, Alec J; Rusinek, Henry; Lisi, Virna; Bennett, Genevieve L; Macari, Michael; Israel, Gary M; Krinsky, Glenn A
2002 Jun;15(2):84-90, Journal of digital imaging
Using receiver-operating characteristic (ROC) methodology, the ability to diagnose acute appendicitis with computed tomography (CT) images displayed at varying levels of lossy compression was evaluated. Nine sequential images over the ileocecal region were obtained from 53 consecutive patients with right lower quadrant pain who were clinically suspected to have acute appendicitis. Thirty were proven surgically to have acute appendicitis, alternative diagnoses confirmed in 23. The image sets were subjected to a lossy wavelet-based compression algorithm 'Embedded Predictive Wavelet Image Coder' (EPWIC). Compression levels were: none, 8:1, 16:1, and 24:1, resulting in 4 sets of images per patient. Image sets were randomized and evaluated separately by 4 body radiologists on a 1,024 x 768-pixel SVGA color PC monitor in 512 x 512 format. The readers were aware of the clinical suspicion of appendicitis but were unaware of the positive fraction of cases. Individual and combined reader ROC and c2 analyses of sensitivity, specificity, and accuracy were determined. For all readers, sensitivity decreases at 16:1 and 24:1 levels (P <0.01, P <0.001, respectively). Accuracy decreased at 24:1 levels (P <0.01). Specificity was unaffected. By ROC analysis there was statistically significantly decreased area under the curve at 24:1 levels (P <0.02) as compared with uncompressed images. Finite levels of lossy wavelet compression may be applied to CT images without compromising diagnostic performance
— id: 43659, year: 2002, vol: 15, page: 84, stat: Journal Article,

Cognitive performance in schizophrenia: relationship to regional brain volumes and psychiatric symptoms
Sanfilipo, Michael; Lafargue, Todd; Rusinek, Henry; Arena, Luigi; Loneragan, Celia; Lautin, Andrew; Rotrosen, John; Wolkin, Adam
2002 Nov 30;116(1-2):1-23, Psychiatry research
In an all-male sample of schizophrenic patients stabilized by medication (n=62) and normal controls (n=27), we obtained neuropsychological test data and high-resolution whole brain magnetic resonance scans, as well as detailed psychiatric rating scales on a subset of the patients (n=47). Schizophrenic patients had significantly worse overall age-adjusted cognitive performance than normal controls (average z-score=-0.90, range=-0.60 to -1.81), which included relatively more severe deficits with different types of memory, psychomotor speed, verbal fluency and verbal abstraction. Schizophrenic patients also had significantly smaller bilateral volumes in gray but not white matter in the prefrontal region, superior temporal gyrus and whole temporal lobe, but no group differences were observed in the hippocampus and parahippocampus. Correlations between the brain regions and cognitive performance revealed different sets of significant relationships for the two groups, particularly in the prefrontal and hippocampal regions. In addition, inverse correlations were observed between certain cognitive abilities (psychomotor speed, cognitive flexibility and verbal fluency) and patients' psychiatric ratings, especially with measures of negative symptoms. The convergence of findings for schizophrenic patients regarding the prefrontal region, negative symptoms, psychomotor speed and cognitive flexibility suggests that schizophrenic negative symptoms may involve disruption of frontal-subcortical connections
— id: 73261, year: 2002, vol: 116, page: 1, stat: Journal Article,

Prediction of cognitive decline in normal elderly subjects with 2-[(18)F]fluoro-2-deoxy-D-glucose/poitron-emission tomography (FDG/PET)
de Leon MJ; Convit A; Wolf OT; Tarshish CY; DeSanti S; Rusinek H; Tsui W; Kandil E; Scherer AJ; Roche A; Imossi A; Thorn E; Bobinski M; Caraos C; Lesbre P; Schlyer D; Poirier J; Reisberg B; Fowler J
2001 Sep 11;98(19):10966-10971, Proceedings of the National Academy of Sciences of the United States of America
Neuropathology studies show that patients with mild cognitive impairment (MCI) and Alzheimer's disease typically have lesions of the entorhinal cortex (EC), hippocampus (Hip), and temporal neocortex. Related observations with in vivo imaging have enabled the prediction of dementia from MCI. Although individuals with normal cognition may have focal EC lesions, this anatomy has not been studied as a predictor of cognitive decline and brain change. The objective of this MRI-guided 2-[(18)F]fluoro-2-deoxy-d-glucose/positron-emission tomography (FDG/PET) study was to examine the hypothesis that among normal elderly subjects, EC METglu reductions predict decline and the involvement of the Hip and neocortex. In a 3-year longitudinal study of 48 healthy normal elderly, 12 individuals (mean age 72) demonstrated cognitive decline (11 to MCI and 1 to Alzheimer's disease). Nondeclining controls were matched on apolipoprotein E genotype, age, education, and gender. At baseline, metabolic reductions in the EC accurately predicted the conversion from normal to MCI. Among those who declined, the baseline EC predicted longitudinal memory and temporal neocortex metabolic reductions. At follow-up, those who declined showed memory impairment and hypometabolism in temporal lobe neocortex and Hip. Among those subjects who declined, apolipoprotein E E4 carriers showed marked longitudinal temporal neocortex reductions. In summary, these data suggest that an EC stage of brain involvement can be detected in normal elderly that predicts future cognitive and brain metabolism reductions. Progressive E4-related hypometabolism may underlie the known increased susceptibility for dementia. Further study is required to estimate individual risks and to determine the physiologic basis for METglu changes detected while cognition is normal
— id: 26662, year: 2001, vol: 98, page: 10966, stat: Journal Article,

Hippocampal formation glucose metabolism and volume losses in MCI and AD
De Santi S; de Leon MJ; Rusinek H; Convit A; Tarshish CY; Roche A; Tsui WH; Kandil E; Boppana M; Daisley K; Wang GJ; Schlyer D; Fowler J
2001 Jul-Aug;22(4):529-539, Neurobiology of aging
We used MRI volume sampling with coregistered and atrophy corrected FDG-PET scans to test three hypotheses: 1) hippocampal formation measures are superior to temporal neocortical measures in the discrimination of normal (NL) and mild cognitive impairment (MCI); 2) neocortical measures are most useful in the separation of Alzheimer disease (AD) from NL or MCI; 3) measures of PET glucose metabolism (MRglu) have greater diagnostic sensitivity than MRI volume. Three groups of age, education, and gender matched NL, MCI, and AD subjects were studied. The results supported the hypotheses: 1) entorhinal cortex MRglu and hippocampal volume were most accurate in classifying NL and MCI; 2) both imaging modalities identified the temporal neocortex as best separating MCI and AD, whereas widespread changes accurately classified NL and AD; 3) In most between group comparisons regional MRglu measures were diagnostically superior to volume measures. These cross-sectional data show that in MCI hippocampal formation changes exist without significant neocortical changes. Neocortical changes best characterize AD. In both MCI and AD, metabolism reductions exceed volume losses
— id: 21136, year: 2001, vol: 22, page: 529, stat: Journal Article,

Volume quantitation of small pulmonary nodules on low-dose chest
Ko, JP; Rusinek, H; Chandra, R; McGuinness, G; Betke, M; Naidich, DP
2001 NOV ;221(2):312-312, Radiology
— id: 73267, year: 2001, vol: 221, page: 312, stat: Journal Article,

MR renography with low-dose gadopentetate dimeglumine: feasibility
Lee VS; Rusinek H; Johnson G; Rofsky NM; Krinsky GA; Weinreb JC
2001 Nov;221(2):371-379, Radiology
PURPOSE: To develop a low-dose magnetic resonance (MR) renographic method performed with and without an angiotensin converting enzyme (ACE) inhibitor and in conjunction with gadolinium-enhanced MR angiography in patients with suspected renovascular disease. MATERIALS AND METHODS: Thirty-two patients underwent MR renography (turbo fast low-angle shot sequence: repetition time, 5 msec; echo time, 2.3 msec; flip angle, 15 degrees; one coronal image acquired every 2 seconds for 4 minutes) following intravenous injection of 2 mL of gadopentetate dimeglumine, which was repeated following intravenous injection of an ACE inhibitor. Contrast material-enhanced MR angiography was also performed. On the basis of renographic findings, renal cortex and renal medulla enhancement curves and normalized enhancement ratios were analyzed. RESULTS: The cortex and medulla showed an early transient period of enhancement within 20 seconds (vascular phase). During 1-2 minutes, a second, gradual increase in medullary enhancement, reflecting transit of filtered contrast material, was observed that was significantly greater in patients with a serum creatinine level less than 2 mg/dL (177 micromol/L) than in those with a level of 2 mg/dL or greater (P < .01). After injection of the ACE inhibitor, patients with elevated creatinine levels showed low renal medullary enhancement regardless of the presence of renal artery stenosis (RAS). However, in patients with creatinine less than 2 mg/dL, medullary enhancement ratios after injection of the ACE inhibitor were consistently lower in patients with RAS of 50% or greater than in those without stenosis (P = .02 to .08). CONCLUSION: Low-dose MR renography can be performed in the clinical setting before and after injection of an ACE inhibitor, and its potential use for evaluating decreased renal function as a consequence of RAS is promising
— id: 26587, year: 2001, vol: 221, page: 371, stat: Journal Article,

Dynamic three-dimensional MR renography for the measurement of glomerular filtration rate
Lee, VS; Rusinek, H; Lee, P; Kramer, EL; Lavelle, MT; Weinreb, JC
2001 NOV ;221(2):633-634, Radiology
— id: 73269, year: 2001, vol: 221, page: 633, stat: Journal Article,

CT interpretation utilizing compressed image data: Acute appendicitis as a model for assessing diagnostic quality
Megibow, AJ; Rusinek, H; Lisi, V; Macari, MJ; Bennett, GL; Israel, GM
2001 NOV ;221(2):377-377, Radiology
— id: 73268, year: 2001, vol: 221, page: 377, stat: Journal Article,

Optimal dose of Gd-DTPA in dynamic MR studies
Rusinek H; Lee VS; Johnson G
2001 Aug;46(2):312-316, Magnetic resonance in medicine
The relationship between the administered dose d of Gd-DTPA and the accuracy of measurements of the glomerular filtration rate G and the cardiac output O was investigated. For a wide range of values the concentration of Gd-DTPA can be uniquely derived from MR signals and precontrast longitudinal relaxation time. Fixed and random errors in these measured variables were analyzed. Depending on noise level and the level of renal function, errors in G reach a minimum for d = 1.4-2.8 mmol. Random errors in G are relatively insensitive to d as long as d > 1.5 mmol. These results establish the feasibility of dynamic MR measurements using doses of Gd-DTPA that are several times lower than current standards
— id: 26716, year: 2001, vol: 46, page: 312, stat: Journal Article,

The histological validation of post mortem magnetic resonance imaging-determined hippocampal volume in Alzheimer's disease
Bobinski M; de Leon MJ; Wegiel J; Desanti S; Convit A; Saint Louis LA; Rusinek H; Wisniewski HM
2000 ;95(3):721-725, Neuroscience
For 11 AD cases and four normal elderly controls, post mortem volumes of the hippocampal subdivisions were calculated by using magnetic resonance imaging and histological sections. After at least six weeks of fixation in formalin, brains were examined on a 1.5-T Philips Gyroscan imager producing T1-weighted coronal images with a 3-mm slice thickness. Brains were then processed and embedded in paraffin. Serial coronal sections, 3 mm apart and stained with Cresyl Violet, were used for the planimetry and unbiased estimation of the total numbers of neurons in the hippocampal subdivisions. For all 15 cases, magnetic resonance imaging- and histology-based measurements were performed along the whole rostrocaudal extent of the hippocampal formation and included three subvolumes: (i) the hippocampus (CA1-CA4 and the dentate gyrus); (ii) hippocampus/subiculum; and (iii) hippocampus/parahippocampal gyrus. After controlling for shrinkage, strong correlations were found between magnetic resonance imaging and histological measurements for the hippocampus (r = 0.97, P < 0.001), hippocampus/subiculum (r = 0.95, P < 0.001) and hippocampus/parahippocampal gyrus (r = 0.89, P < 0.001). We also calculated the total number of neurons in the hippocampus and hippocampus/subiculum subvolumes. Strong correlations between the magnetic resonance imaging subvolumes and neuronal counts were found for the hippocampus (r = 0.90, P < 0.001) and the hippocampus/subiculum subvolume (r = 0.84, P < 0.001). We conclude that very accurate volumetric measurements of the whole hippocampal formation can be obtained by using a magnetic resonance imaging protocol. Moreover, the strong correlations between magnetic resonance imaging-based hippocampal volumes and neuronal numbers suggest the anatomical validity of magnetic resonance imaging volume measurements
— id: 8584, year: 2000, vol: 95, page: 721, stat: Journal Article,

Atrophy of the medial occipitotemporal, inferior, and middle temporal gyri in non-demented elderly predict decline to Alzheimer's disease
Convit A; de Asis J; de Leon MJ; Tarshish CY; De Santi S; Rusinek H
2000 Jan-Feb;21(1):19-26, Neurobiology of aging
Our goal was to ascertain, among normal elderly and individuals with mild cognitive impairment, which temporal lobe neocortical regions predicted decline to dementia of the Alzheimer's type (DAT). Individuals received an MRI at baseline and a clinical and cognitive evaluation at baseline and follow-up. By using the baseline MRI we assessed the anatomical subdivisions of the temporal lobe: anteromedial temporal lobe (hippocampus and parahippocampal gyrus), medial occipitotemporal (fusiform) gyrus, middle and inferior temporal gyri, and superior temporal gyrus. We studied two groups of carefully screened age- and education-matched elderly individuals: 26 normal elderly (NL) and 20 individuals with mild cognitive impairment (MCI). Fourteen individuals (12 from the MCI group and two from the NL group) declined to DAT within the 3.2-year follow-up interval. We used logistic regression analyses to ascertain whether the baseline brain volumes were useful predictors of decline to DAT at follow-up after accounting for age, gender, individual differences in brain size, and other variables known to predict DAT. After accounting for age, gender, and head size, adding the volume of the anteromedial temporal lobe (the aggregate of hippocampus and parahippocampal gyrus) and an index of global atrophy raised the accuracy of overall classification to 80.4%. However, the ability to detect those individuals who declined (sensitivity) was low at 57%. When baseline medial occipitotemporal and the combined middle and inferior temporal gyri were added to the logistic model, the overall classification accuracy reached 95.6% and, most importantly, the sensitivity rose to 92.8%. These data indicate that the medial occipitotemporal and the combined middle and inferior temporal gyri may be the first temporal lobe neocortical sites affected in AD; atrophy in these areas may herald the presence of future AD among nondemented individuals. No other clinical baseline variables examined predicted decline with sensitivities above 71%. The apolipoprotein APOE epsilon4 genotype was not associated with decline
— id: 9442, year: 2000, vol: 21, page: 19, stat: Journal Article,

Fine volumetric analysis of the cerebral ventricular system in schizophrenia: further evidence for multifocal mild to moderate enlargement
Sanfilipo M; Lafargue T; Arena L; Rusinek H; Kushner K; Lautin A; Loneragan C; Vaid G; Rotrosen J; Wolkin A
2000 ;26(1):201-216, Schizophrenia bulletin
We used traditional volumetric regional analysis and a finer anterior-posterior (AP) profile volumetric analysis to examine the cerebral ventricular system in an all-male, demographically matched sample of schizophrenia patients (n = 73) and normal controls (n = 29) using 2.8-mm-thin coronal T1-weighted magnetic resonance images from a 1.5 tesla scanner. Traditional regional analysis was performed on various regions using absolute volumes after adjusting for intracranial volume (ICV) and age. The fine AP profile analysis was done by intrasubject 'stacking' of contiguous coronal cross-sectional volumes (adjusted for ICV and age) across the AP plane, intersubject AP alignment of all slices relative to the mammillary bodies, and plotting of slice volumes along the AP plane with 95 percent t-test-based confidence intervals. Schizophrenia subjects had mild to moderate multifocal ventricular enlargement (overall effect size d = 0.48), which was especially prominent in the right posterior temporal horn and, more generally, in the central to posterior portions of the lateral and third ventricles. Schizophrenia subjects also had milder enlargement in the left frontal horn, but no significant differences were found in the anterior temporal horns and the right frontal horn. Post hoc analyses of demographic, clinical, and neuropsychological variables did not account for much variance in the ventriculomegaly observed in the schizophrenia group. The lack of a single locus in the observed ventricular enlargement, the nonsignificant results from schizophrenia subtypes based on regional distributions, and the strong positive correlations among the ventricular regions for the schizophrenia group suggest that the ventriculomegaly seen in this chronic population reflects a single brainwide disease process leading to a multifocal or patchy loss of integrity in brain structure
— id: 23575, year: 2000, vol: 26, page: 201, stat: Journal Article,

Volumetric measure of the frontal and temporal lobe regions in schizophrenia: relationship to negative symptoms
Sanfilipo M; Lafargue T; Rusinek H; Arena L; Loneragan C; Lautin A; Feiner D; Rotrosen J; Wolkin A
2000 May;57(5):471-480, Archives of general psychiatry
BACKGROUND: Previous research has provided evidence for brain abnormalities in schizophrenia, but their relationship to specific clinical symptoms and syndromes remains unclear. METHODS: With an all-male demographically similar sample of 53 schizophrenic patients and 29 normal control subjects, cerebral gray and white matter volumes (adjusted for intracranial volume and age were determined for regions in the prefrontal lobe and in the superficial and mesial temporal lobe using T1-weighted magnetic resonance imaging with 2.8-mm coronal slices. RESULTS: As a group, schizophrenic patients had wide-spread bilateral decrements in gray matter in the pre-frontal (7.4%) and temporal lobe regions (8.9%), but not in white matter in these regions. In the temporal lobe, gray matter reductions were found bilaterally in the superior temporal gyrus (6.0%), but not in the hippocampus and parahippocampus. While there were no overall group differences in white matter volumes, widespread decrements in prefrontal white matter in schizophrenic patients (n = 53) were related to higher levels of negative symptoms (partial r[49] = -0.42, P = .002), as measured by the Scale for the Assessment of Negative Symptoms. A post hoc analysis revealed that schizophrenic patients with high negative symptoms had generalized prefrontal white matter reductions (11.4%) that were most severe in the orbitofrontal subregion (15.1%). CONCLUSIONS: These results suggest that gray matter deficits may be a fairly common structural abnormality of schizophrenia, whereas reductions in prefrontal white matter may be associated with schizophrenic negative symptoms
— id: 23576, year: 2000, vol: 57, page: 471, stat: Journal Article,

ACE-inhibitor-enhanced ultra-low dose Gd-DTPA MR renography performed in conjunction with breath-hold Gd-M
Lee, VS; Rusinek, H; Johnson, G; Yoon, S; Kim, R; Krinsky, GA
1999 NOV ;213P(3):217-217, Radiology
— id: 73270, year: 1999, vol: 213P, page: 217, stat: Journal Article,

Open permanent unipolar magnets (interventional applications)
Abele, Manlio G.; Rusinek, Henry; Jensen, Jens H
[New York, N.Y.] : NYU Medical Center, c1998,
— id: 589, year: 1998, vol: , page: , stat: ,

Effect of a haloperidol challenge on regional brain metabolism in neuroleptic-responsive and nonresponsive schizophrenic patients
Bartlett EJ; Brodie JD; Simkowitz P; Schlosser R; Dewey SL; Lindenmayer JP; Rusinek H; Wolkin A; Cancro R; Schiffer W
1998 Mar;155(3):337-343, American journal of psychiatry
OBJECTIVE: The CNS metabolic response to a neuroleptic challenge in treatment-responsive and nonresponsive schizophrenic patients was measured in order to examine the relation between treatment outcome and the capacity to alter neurochemical function in response to acute receptor blockade. METHOD: Positron emission tomography (PET) and [18F]fluorodeoxyglucose (FDG) were used to measure regional cerebral metabolism in seven schizophrenic patients judged to have been responsive to drug treatment previously and seven nonresponsive schizophrenic patients after a drug-free period of at least 3 weeks (baseline) and again 12 hours after administration of 5.0 mg of haloperidol. RESULTS: The haloperidol challenge caused widespread decreases in absolute metabolism in the nonresponsive patients but not the responsive patients. These group differences reflect the findings on the second (challenge) scans, since metabolic values at baseline were not statistically different in the two groups. The pattern of decreased metabolic activity in the nonresponders after the haloperidol challenge is similar to that previously observed in normal subjects. CONCLUSIONS: The metabolic response to drug challenge separates treatment responders from nonresponders and normal subjects. The results suggest that subtyping of schizophrenia (and other psychiatric disorders) can be achieved by measuring the physiologic response to a pharmacologic challenge in vivo with chemical brain-imaging techniques
— id: 7497, year: 1998, vol: 155, page: 337, stat: Journal Article,

MR differential diagnosis of normal-pressure hydrocephalus and Alzheimer disease: significance of perihippocampal fissures
Holodny AI; Waxman R; George AE; Rusinek H; Kalnin AJ; de Leon M
1998 May;19(5):813-819, AJNR. American journal of neuroradiology
PURPOSE: In the older patient with dilated ventricles, it is often difficult to differentiate normal pressure hydrocephalus (NPH) from cerebral atrophy caused by Alzheimer disease (AD). This study was undertaken to see if dilatation of the perihippocampal fissures (PHFs) could be used as a distinguishing characteristic of these two disorders. METHODS: MR images of 17 patients with AD were compared with those from an equal number of patients with NPH who improved after ventriculoperitoneal shunting. The PHFs, lateral ventricles, third ventricle, and temporal horns were graded subjectively. Objective, computer-aided volumetric measurements of the PHFs and lateral ventricles were obtained. The preshunt images of the NPH patients were evaluated. RESULTS: Significant differences between the two groups were found for the PHFs and lateral ventricles by both the subjective and objective methods, with a high degree of correlation between the two methods. CONCLUSION: The degree of dilatation of PHFs appears to be a sensitive and specific marker for differentiating AD from NPH by both subjective and objective means, with a very small overlap between the two groups. This observation may have relevance in day-to-day practice
— id: 12119, year: 1998, vol: 19, page: 813, stat: Journal Article,

Pulmonary nodule detection: low-dose versus conventional CT
Rusinek H; Naidich DP; McGuinness G; Leitman BS; McCauley DI; Krinsky GA; Clayton K; Cohen H
1998 Oct;209(1):243-249, Radiology
PURPOSE: To quantitate the effectiveness of low-dose computed tomography (CT) in the identification of pulmonary nodules while controlling for anatomic nodule characteristics and to establish what factors lead to reduced diagnostic sensitivity at low-dose CT. MATERIALS AND METHODS: Each of six participating radiologist independently rated 200 image panels by using a four-point confidence scale. Conventional images were obtained at 200 mAs; low-dose images were obtained at 20 mAs. To fully control their characteristics, nodules were simulated with a given diameter, shape, and section thickness while preserving the resolution, noise level, and reconstruction artifacts of the original images. Panels were matched so that nodules on low-dose and conventional images had equivalent sizes, locations, and relationships to blood vessels. RESULTS: Among 864 positive panels, 259 (60%) of 432 low-dose panels and 272 (63%) of 432 conventional panels were correctly interpreted (P = .259). Lowering the x-ray dose significantly reduced the detectability of peripheral nodules (P = .019) and nodules separated from blood vessels (P = .044). Surprisingly, 3-mm nodules were detected with approximately equal sensitivity (P = .181) at conventional and low-dose CT. The specificity of low-dose images was 88% (148 of 168 panels) versus 91% (153 of 168 panels) for conventional images (P = .372). CONCLUSION: Low-dose CT is acceptable for pulmonary nodule identification, making it suitable for primary screening. These results confirm the strong effect of size, location, and angiocentricity on the sensitivity of nodule detection with conventional CT
— id: 7773, year: 1998, vol: 209, page: 243, stat: Journal Article,

Inter-subject coregistration of brain images : a phantom study
Rusinek H; Tsui W-H; Sanfilipo M; Wolkin A
1998 ;3338:61-69, Medical imaging. Image processing (SPIE)
— id: 73287, year: 1998, vol: 3338, page: 61, stat: Journal Article,

Fibroglandular breast tissue assessments by mammography and MR imaging - Reply
Rusinek, H; Weinreb, J; Chandra, R; Newstead, G
1998 MAY ;170(5):1397-1398, American journal of roentgenology
— id: 53512, year: 1998, vol: 170, page: 1397, stat: Journal Article,

Functional magnetic resonance imaging of human brain activity in a verbal fluency task
Schlosser R; Hutchinson M; Joseffer S; Rusinek H; Saarimaki A; Stevenson J; Dewey SL; Brodie JD
1998 Apr;64(4):492-498, Journal of neurology neurosurgery & psychiatry
OBJECTIVES: Functional MRI (fMRI) holds the promise of non-invasive mapping of human brain function in both health and disease. Yet its sensitivity and reliability for mapping higher cognitive function are still being determined. Using verbal fluency as a task, the objective was to ascertain the consistency of fMRI on a conventional scanner for determining the anatomic substrate of language between subjects and between sexes. Comparison was made with previous PET studies. METHODS: Using a 1.5 Tesla magnet and an echoplanar pulse sequence, whole brain fMRI was obtained from 12 normal right handed subjects (6 males and 6 females) as they performed a verbal fluency task. RESULTS: A broadly consistent pattern of response was seen across subjects. Areas showing activation changes included the left prefrontal cortex and right cerebellum, in agreement with previous PET 15O-H2O studies. In addition, significantly decreased responses were seen in the posterior cingulate and over an extensive area of mesial and dorsolateral parietal and superior temporal cortices. The male cohort showed a slight asymmetry of parietal deactivation, with more involvement on the right, whereas the female cohort showed a small region of activation in the right orbitofrontal cortex. There were individual task related regional changes in all 12 subjects with the area showing the most significant change being the left prefrontal cortex in all cases. CONCLUSIONS: Magnetic resonance scanners of conventional field strength can provide functional brain mapping data with a sensitivity at least that of PET. Activation was seen in left prefrontal and right cerebellar regions, as with PET. However, decremental responses were seen over a much larger area of the posterior cortex than had been anticipated by prior studies. The ability to see a response in each subject individually suggests that fMRI may be useful in the preinterventional mapping of pathological states, and offers a non-invasive alternative to the Wada test for assessment of hemispheric dominance. There were no gross differences in the pattern of activation between male and female subjects
— id: 57250, year: 1998, vol: 64, page: 492, stat: Journal Article,

Structural magnetic resonance image averaging in schizophrenia
Wolkin A; Rusinek H; Vaid G; Arena L; Lafargue T; Sanfilipo M; Loneragan C; Lautin A; Rotrosen J
1998 Aug;155(8):1064-1073, American journal of psychiatry
OBJECTIVE: Intersubject averaging of structural magnetic resonance (MR) images has been infrequently used as a means to study group differences in cerebral structure throughout the brain. In the present study, the authors used linear intersubject averaging of structural MR images to evaluate the validity and utility of this technique and to extend previous research, conducted using a different approach to image averaging, in which reduction in thalamic size and abnormalities in perithalamic white matter tracts in the brains of schizophrenic patients were reported by Andreasen et al. METHOD: A 1.5-T MR scanner was used to obtain high-resolution, whole brain T1-weighted structural MR images for an age-matched sample of 25 schizophrenic patients and 25 normal control subjects. A 'bounding box' procedure was used to create a single 'averaged' brain for the schizophrenic group and for the control group. Differences in signal intensity between the two average brains were examined on a pixel-wise basis through use of one-tailed effect size maps. RESULTS: Effect size maps revealed widespread patchy signal intensity differences between the two groups in both cortical and periventricular areas, including major white matter tracts. The signal intensity differences were consistent with cortical thinning/sulcal widening and ventricular enlargement. No differences were found within thalamus or in immediately surrounding white matter. Effect size maps for differences (schizophrenic minus normal subjects) had only small values. CONCLUSIONS: These results are consistent with diffuse structural brain abnormalities of both gray and white matter in schizophrenic populations such as the one in this study
— id: 23577, year: 1998, vol: 155, page: 1064, stat: Journal Article,

Generation of uniform high fields with magnetized wedges
Abele, MG; Jensen, JH; Rusinek, H
1997 SEP ;33(5):3874-3876, IEEE transactions on magnetics
The properties of permanent magnets composed of uniformly magnetized wedges are presented in this paper. The magnets are fully open structures capable of generating strong fields exceeding the remanence of the material
— id: 73271, year: 1997, vol: 33, page: 3874, stat: Journal Article,

Specific hippocampal volume reductions in individuals at risk for Alzheimer's disease
Convit A; De Leon MJ; Tarshish C; De Santi S; Tsui W; Rusinek H; George A
1997 Mar-Apr;18(2):131-138, Neurobiology of aging
Our goal was to ascertain the involvement of the temporal lobe in the preclinical (not yet diagnosable) stages of dementia of the Alzheimer's type (DAT) by using MRI-derived volumes. We assessed anatomical subdivisions of the temporal lobe on three groups of carefully screened age- and education-matched elderly individuals: 27 normal elderly (NL), 22 individuals with minimal cognitive impairment (MCI), who did not fulfill DAT criteria but were regarded at high risk for future DAT, and 27 DAT individuals. We found hippocampal volume reductions of 14% for the MCI and 22% for the DAT group compared to the NL group. Utilizing regression analyses and after accounting for gender head size-age, generalized atrophy (CSF), and other temporal lobe subvolumes, the hippocampal volume separated NL from MCI individuals, correctly classifying 74%. For NL and MCI groups combined the hippocampal volume was the only temporal lobe subvolume related to delayed recall memory performance. When contrasting MCI and DAT individuals, the fusiform gyrus volume uniquely improved the ability of the hippocampal volume to separate MCI from DAT individuals from 74 to 80%. Our cross-sectional data suggest that, within the temporal lobe, specific hippocampal volume reductions separated the group at risk for DAT from the normal group. By the time impairments are sufficient to allow a diagnosis of DAT to be made, in addition to the medial temporal lobe volume reductions, the lateral temporal lobe is also showing volume reductions, most saliently involving the fusiform gyrus
— id: 7134, year: 1997, vol: 18, page: 131, stat: Journal Article,

Hippocampal atrophy as detected by width of the temporal horn is greater in Alzheimer dementia than in nondementing cognitive impairment - Comment
Convit, A; deLeon, MJ; Tarshish, C; DeSanti, S; Wells, C; George, A; SaintLouis, LA; Rusinek, H
1997 JUN-JUL ;18(6):1193-1195, AJNR. American journal of neuroradiology
— id: 73272, year: 1997, vol: 18, page: 1193, stat: Journal Article,

Contribution of structural neuroimaging to the early diagnosis of Alzheimer's disease
de Leon MJ; Convit A; DeSanti S; Bobinski M; George AE; Wisniewski HM; Rusinek H; Carroll R; Saint Louis LA
1997 ;9 Suppl 1:183-190, International psychogeriatrics
There is compelling evidence for the early involvement of the hippocampal formation in the natural history of Alzheimer's disease (AD). The evidence comes from recent neuropathology, neuropsychology, and neuroimaging studies. AD-type histopathologic changes limited to the hippocampus have been described and may be seen in normal aging subjects. The sites of maximal neuronal loss in the hippocampal formation are in the CA1, subiculum, and entorhinal cortex. Minimally cognitively impaired (MCI) individuals (defined by ratings of functional capacity and psychiatric symptomatology) exhibit a neuropsychological profile that is distinct from that of the unimpaired elderly. Pathologic evidence suggests that most of these cases already have AD brain changes accentuated in the hippocampal region, and our own longitudinal studies reveal that 70% of this group develop dementia within a 4-year period. We have developed a negative-angle axial view designed to cut parallel to the anterior-posterior plane of the hippocampus. Using this modified axial plane of section in conjunction with computed tomography (CT) and magnetic resonance imaging (MRI), we estimated the prevalence of hippocampal atrophy in normal aging and across severity levels of cognitively impaired elderly patients. Longitudinal study shows that hippocampal atrophy is a sensitive and specific predictor of future AD for patients with MCI. MRI volume study of AD patients, controls, and MCI patients shows specific hippocampal volume loss in MCI. We conclude that the atrophic changes associated with early AD can be visualized using qualitative techniques and are readily quantifiable with volumetry. This article is not intended to be comprehensive, but to provide an overview of some of the structural neuroimaging data from our laboratory
— id: 9444, year: 1997, vol: 9 Suppl 1, page: 183, stat: Journal Article,

Frequency of hippocampal formation atrophy in normal aging and Alzheimer's disease
De Leon MJ; George AE; Golomb J; Tarshish C; Convit A; Kluger A; De Santi S; McRae T; Ferris SH; Reisberg B; Ince C; Rusinek H; Bobinski M; Quinn B; Miller DC; Wisniewski HM
1997 Jan-Feb;18(1):1-11, Neurobiology of aging
We used CT and MR to examine the frequency of occurrence of hippocampal formation atrophy (HA) in a research clinic population of 130 normal elderly, 72 nondemented patients with very mild memory and cognitive impairments (MCI), 73 mild Alzheimer's disease (AD) patients, and 130 patients with moderate to severe AD. HA was found in 29% of the normal elderly group and its frequency of occurrence was strongly related to increasing age. For normal elderly 60-75 years of age, 15% had HA: the proportion rose to 48% in subjects 76-90 years of age. Among the three groups of impaired patients, the frequencies of HA ranged from 78% in the MCI patients to 96% in the advanced AD group. Unlike the normal elderly group, the percentages were not related to age. In both the normal elderly group and MCI group disproportionately more males than females had HA. After controlling for learning and the effects of generalized brain changes as reflected in ventricular size, only in the normal group was HA associated with reduced delayed verbal recall performance. Follow-up examinations for 15 individuals with baseline HA. 4 who at entry were MCI and 11 probable AD, yielded clinical and neuropathologic diagnoses of AD in all cases. The results of the present study indicate that hippocampal formation atrophy is associated with memory and cognitive impairments. Further longitudinal and neuropathologic work is required to validate the relationship between hippocampal formation atrophy and AD
— id: 9449, year: 1997, vol: 18, page: 1, stat: Journal Article,

Cortisol reduces hippocampal glucose metabolism in normal elderly, but not in Alzheimer's disease
de Leon MJ; McRae T; Rusinek H; Convit A; De Santi S; Tarshish C; Golomb J; Volkow N; Daisley K; Orentreich N; McEwen B
1997 Oct;82(10):3251-3259, Journal of clinical endocrinology & metabolism
Glucocorticoids are known to play a role in the regulation of peripheral glucose mobilization and metabolism. Although several animal studies have shown that hippocampal glucose metabolism is reduced acutely and chronically by the action of corticosterone and that excess glucocorticoids are harmful to hippocampal neurons, little is known about the central effects of glucocorticoids in the human. In this study we examined the brain glucose utilization (CMRglu) response to hydrocortisone (cortisol) in seven normal elderly and eight Alzheimer's disease (AD) patients. On 2 separate days, immediately after the administration of a bolus of either 35 mg hydrocortisone or placebo, we administered 2-deoxy-2-[18F]fluoro-D-glucose. After a 35-min radiotracer uptake period, positron emission tomography (PET) images were collected. PET CMRglu images were analyzed using two methods: an image transformation that allowed analyses across cases on a voxel by voxel basis, and an anatomically based region of interest method that used coregistered magnetic resonance imaging scans. Both image analysis methods yielded similar results, identifying relative to placebo, a specific hippocampal CMRglu reduction in response to the hydrocortisone challenge that was restricted to the normal group. The region of interest technique showed CMRglu reductions of 16% and 12% in the right and left hippocampi, respectively. Blood collected during the PET scans showed, for the normal group, a rise in plasma glucose levels, starting approximately 25 min after hydrocortisone administration. The AD group did not show this effect. Baseline cortisol was elevated in the AD group, but the clearance of hydrocortisone was not different between the groups. In conclusion, these data show that among normal individuals in the presence of a pharmacological dose of cortisol, the glucose utilization of the hippocampus is specifically reduced, and serum glucose levels increase. Based in part on other studies, we offer the interpretation that glucocorticoid-mediated regulation of glucose transport is altered in AD, and this may underlie both the hippocampal insensitivity to cortisol and the failure in these patients to mount a peripheral glucose response. As our findings could reflect an altered state of the AD patients, we interpret our results as preliminary with respect to evidence for metabolic abnormalities in AD. The results suggest the continued study of the hydrocortisone challenge as a test of hippocampal responsivity
— id: 9447, year: 1997, vol: 82, page: 3251, stat: Journal Article,

Segmentation analysis in functional MRI: activation sensitivity and gray-matter specificity of RARE and FLASH
Hutchinson M; Rusinek H; Nenov VI; Feinberg DA; Johnson G
1997 Mar-Apr;7(2):361-364, Journal of magnetic resonance imaging
Brain activation is accompanied by local decreases in vascular deoxyhemoglobin. Theoretically, gradient-echo and spin-echo sequences show similar sensitivity to capillary deoxyhemoglobin, but spin-echo sequences should be less sensitive to venous deoxyhemoglobin. This is an important distinction in the context of cortical localization. We report herein a direct experimental comparison of a gradient-echo sequence (fast low-angle shot [FLASH]) with a spin-echo sequence (rapid acquisition with relaxation enhancement [RARE]) for functional MRI (fMRI) in seven subjects undergoing visual stimulation. A Student t test analysis was used to locate areas of significant activation, and then computerized image segmentation was performed to determine the type of activated tissue. Contrary to previous reports, both sequences proved equally sensitive to overall activation. RARE activation, however, was more specific for gray matter, as suggested by prior theoretical models
— id: 7167, year: 1997, vol: 7, page: 361, stat: Journal Article,

Spatial distribution of residual errors in 3D image coregistration : experimental study
Kuchinski E; Rusinek H; Tsui W-H
1997 ;3034:1065-1072, Medical imaging. Image processing (SPIE)
— id: 73286, year: 1997, vol: 3034, page: 1065, stat: Journal Article,

Fatty and fibroglandular tissue volumes in the breasts of women 20-83 years old: comparison of X-ray mammography and computer-assisted MR imaging [see comments]
Lee NA; Rusinek H; Weinreb J; Chandra R; Toth H; Singer C; Newstead G
1997 Feb;168(2):501-506, American journal of roentgenology
OBJECTIVE: A method for segmenting MR images of the breast was applied to determine fatty and fibroglandular tissue volumes in breasts of women in different age groups. The results were compared with subjective assessments of breast density from X-ray mammograms in the same patients. MATERIALS AND METHODS: Two experienced mammographers assessed the percentage of fat in the breasts of 40 women who were 20-83 years old. MR images were obtained on a 1.0-T scanner equipped with a bilateral receive-only breast coil. Images were acquired using a three-dimensional T1-weighted gradient-echo sequence with a 1.25 x 1.4 x 2.5 mm resolution. On average, breast parenchyma appeared in 30 images in each breast. Image segmentation was based on a semiautomated, two-compartmental (fatty and fibroglandular tissue) model that accounts for partial volume effects. To validate the accuracy of the MR imaging segmentation technique, we performed a phantom study using an identical imaging sequence. RESULTS: The accuracy of the MR imaging segmentation of the phantom was of the order of 2%. In our subjects, fat content was 42.5% +/- 30.3% (mean +/- SD) on mammography versus 66.5% +/- 18% on MR images. Although we found a significant correlation (r = .63) between the two techniques, mammography poorly differentiated breasts containing less than 45% fat. When our analysis included only dense breasts (i.e., those containing less than 75% fat on MR images), the correlation coefficient decreased to .34. The largest discrepancies between mammography and MR imaging occurred in breasts that had 60-80% fat as measured on MR imaging. CONCLUSION: Fatty and fibroglandular tissue can be differentiated on MR images of the breast with high precision and accuracy, therefore allowing assessment of breast density. The conclusions of researchers who used mammographic density patterns should be reassessed
— id: 12393, year: 1997, vol: 168, page: 501, stat: Journal Article,

Generation of high fields with magnetized wedges
Abele, Manlio G.; Jensen, Jens H.; Rusinek, Henry
[New York, N.Y.] : NYU Medical Center, Dept. of Radiology, c1996,
— id: 584, year: 1996, vol: , page: , stat: ,

Properties of permanent wedge magnets
Abele, Manlio G.; Jensen, Jens H.; Rusinek, Henry
[New York, N.Y.] : NYU Medical Center, Dept. of Radiology, c1996,
— id: 560, year: 1996, vol: , page: , stat: ,

Strapped open permanent magnet
Abele, Manlio G.; Jensen, Jens H.; Rusinek, Henry
[New York, N.Y.] : NYU Medical Center, Dept. of Radiology, c1996,
— id: 563, year: 1996, vol: , page: , stat: ,

Wedge magnets : high field multiple wedge structures / by M.G. Abele, J.H. Jensen and H. Rusinek
Abele, Manlio G.; Jensen, Jens H.; Rusinek, Henry
[New York, N.Y.] : NYU Medical Center, Dept. of Radiology, c1996,
— id: 558, year: 1996, vol: , page: , stat: ,

Wedge magnet
Abele, Manlio G.; Rusinek, Henry
[New York, N.Y.] : NYU Medical Center, Dept. of Radiology, c1996,
— id: 562, year: 1996, vol: , page: , stat: ,

Wedge magnets : magnetization tolerances and non zero magnetic susceptibility
Abele, Manlio G.; Rusinek, Henry
[New York, N.Y.] : NYU Medical Center, Dept. of Radiology, c1996,
— id: 559, year: 1996, vol: , page: , stat: ,

Strapping techniques for permanent magnets
Abele, MG; Jensen, JH; Rusinek, H
1996 SEP ;32(5):5082-5084, IEEE transactions on magnetics
The magnetic field distortion due to magnetization tolerances, fabrication imperfections, and design alterations can be reduced by inserting into a permanent magnet structure thin straps of high permeability ferromagnetic material that lie along equipotential surfaces of the ideal field of a theoretical design. Numerical results are given for a simple model showing quantitatively the beneficial effect of strapping in improving the quality of the field
— id: 52759, year: 1996, vol: 32, page: 5082, stat: Journal Article,

Time-dependent effects of a haloperidol challenge on energy metabolism in the normal human brain
Bartlett EJ; Brodie JD; Simkowitz P; Dewey SL; Rusinek H; Volkow ND; Wolf AP; Smith G; Wolkin A; Cancro R
1996 Mar 29;60(2-3):91-99, Psychiatry research
Positron emission tomography and the fluorodeoxyglucose method were used to measure regional brain metabolism before and 2 h after haloperidol (5 mg, i.m.) in 11 young normal men. These data were compared with measures obtained from nine previously studied normal men who had received no drug intervention. Although a previously published study had demonstrated significantly decreased metabolism in whole brain, neocortex, limbic cortex, thalamus, and caudate nucleus 12 h after a 5-mg dose of haloperidol, the present 2-h study did not show significant metabolic changes despite the fact that significant extrapyramidal effects occurred. Taken together, these studies demonstrate differences in the temporal organization of behavioral and metabolic responses to haloperidol challenge
— id: 12632, year: 1996, vol: 60, page: 91, stat: Journal Article,

In vivo structural studies of the hippocampus in normal aging and in incipient Alzheimer's disease
de Leon MJ; Convit A; George AE; Golomb J; de Santi S; Tarshish C; Rusinek H; Bobinski M; Ince C; Miller D; Wisniewski H
1996 Jan 17;777:1-13, Annals of the New York Academy of Sciences
Population trends indicate that in the near future the size of the elderly population will increase. This will result in a large increment in the numbers of persons suffering mild to severe levels of cognitive impairment. While considerable efforts continue to be made to explain brain changes associated with Alzheimer disease (AD), little is known of the brain changes in aging without dementia or so-called normal aging. Pathologic studies suggest that the medial temporal lobe is informative in the examination of the early brain changes related to AD. However, pathologic studies only offer a single observation and considerable uncertainty exists regarding the likelihood of progression of disease and the development of dementia. Several structural neuroimaging studies have recently investigated this anatomy and recent reports are encouraging for a medial temporal lobe based diagnosis for age-related cognitive impairments. We will present our findings on the MRI anatomy of the hippocampal formation as well as data bearing on the use of hippocampal formation imaging in the diagnosis of AD and as a predictive marker for future dementia. Our findings suggest an anatomically specific relationship between hippocampal volume and secondary memory performance. Because these observations apply to nondemented and normal elderly subjects, we are encouraged that the anatomy of age-related cognitive impairments can be reliably recognized and possibly put to use in therapeutic studies
— id: 6989, year: 1996, vol: 777, page: 1, stat: Journal Article,

High-dose administration of nonionic contrast media: a retrospective review [see comments]
Rosovsky MA; Rusinek H; Berenstein A; Basak S; Setton A; Nelson PK
1996 Jul;200(1):119-122, Radiology
PURPOSE: To assess the safety of high-dose nonionic contrast media (CM) during a single radiologic procedure. MATERIALS AND METHODS: From November 1991 to August 1995, 255 high-dose angiographic procedures were performed in 228 patients with normal serum creatinine (SCr) levels (< or = 1.6 mg/dL [141 mumol/L]). All patients received 250-800 mL low-osmolarity CM (300 mg iodine per milliliter). Pre- and postprocedure SCr levels were assessed. Urine output was measured daily in the 75 patients who received more than 400 mL CM. With linear regression analysis, a dose-related elevation in SCr levels was calculated. RESULTS: No patient developed abnormal SCr levels (> 1.6 mg/dL [141 mumol/L]) as a result of the CM. Among the patients who received more than 400 mL, none developed oliguria over the first 36 hours. With follow-up up to 3 years, no patient experienced delayed clinical renal failure. In 11 (4.3%) patients, the SCr levels increased more than 25%, but all increases were within expected limits (chi 2 analysis). Linear regression analysis revealed a 0.015 mg/dL (1 mumol/L) increase in SCr levels per 100 mL CM. CONCLUSION: Intravenous administration of high-dose low-osmolarity iodinated CM appears safe in patients without renal dysfunction or other underlying risk factors, in doses as large as 800 mL (300 mg iodine per milliliter)
— id: 7251, year: 1996, vol: 200, page: 119, stat: Journal Article,

Design of gradient coils for permanent magnets
Wang J; Abele MG; Rusinek H
1996 Jan-Feb;6(1):239-243, Journal of magnetic resonance imaging
Designing gradient coils for permanent magnets requires modeling the interaction between the currents and the ferromagnetic material. We have developed and tested an iterative design approach based on the boundary element method. The power dissipated by the gradient coil is treated as a constraint of the minimization problem. The technique is illustrated on a magnet with a rectangular prismatic cavity and two ferromagnetic plates adjacent to the coil. The procedure improved the linearity of the field from 10.5% to 3.4% and reduced the power dissipation to 63% of the power of the unoptimized coil. The optimized distribution of currents has been transformed to variable locations of coil windings without loss of gradient uniformity. The new approach significantly reduces computation time and memory storage and yields practical designs of gradient coils for permanent magnets
— id: 12674, year: 1996, vol: 6, page: 239, stat: Journal Article,

Transition structures for open permanent magnets
Abele, Manlio G.; Rusinek, Henry
[New York, N.Y.] : NYU Medical Center, Dept. of Radiology, c1995,
— id: 557, year: 1995, vol: , page: , stat: ,

DESIGN OF AN OPEN PERMANENT-MAGNET FOR CLINICAL AND SURGICAL MR-IMAGING
ABELE, MG; JENSEN, JH; RUSINEK, H; CHASE, NE
1995 NOV ;197(1):220-220, Radiology
— id: 73273, year: 1995, vol: 197, page: 220, stat: Journal Article,

OPEN C-SHAPED PERMANENT-MAGNETS FOR NMR IMAGING
ABELE, MG; RUSINEK, H
1995 NOV ;31(6):3740-3742, IEEE transactions on magnetics
Previously developed design methodology provides a systematic analysis of magnetic structures composed of uniformly magnetized prisms that generate uniform fields. The approach is based on the property of cancellation of field singularities at the interfaces between the media. Applications of this design methodology thus far have been restricted to magnetic structures with concave cavity boundaries. However, convex cavity boundaries may be necessary for C-shaped magnetic structures involved in medical NMR imaging that feature a side opening in addition to openings at both ends. This paper introduces transition structures placed in the region of the magnet opening and analyzes their field properties. The results indicate a remarkable benefit of the transition elements in terms of field uniformity and the size of the imaging region
— id: 73275, year: 1995, vol: 31, page: 3740, stat: Journal Article,

Age-related changes in brain: I. Magnetic resonance imaging measures of temporal lobe volumes in normal subjects
Convit A; de Leon MJ; Hoptman MJ; Tarshish C; De Santi S; Rusinek H
1995 Winter;66(4):343-355, Psychiatric quarterly
The volume of temporal lobe structures was examined in twenty-seven older (mean age of 69.2 +/- 8.3 years) and ten younger subjects (mean age of 26.1 +/- 4.1 years) using quantitative magnetic resonance imaging (MRI) methods. Multiple regression analysis, using gender, overall atrophy, and head size as covariates, showed unique contributions of age to variance in both medial and lateral temporal lobe volumes. Temporal lobe subregions that showed the strongest unique age-related reductions were the hippocampus, fusiform gyrus, and parahippocampus. These results suggest age-related reductions in temporal lobe subvolumes
— id: 9455, year: 1995, vol: 66, page: 343, stat: Journal Article,

Hippocampal volume losses in minimally impaired elderly
Convit A; de Leon MJ; Tarshish C; De Santi S; Kluger A; Rusinek H; George AE
1995 Jan 28;345(8944):266-266, Lancet
— id: 9453, year: 1995, vol: 345, page: 266, stat: Journal Article,

HIPPOCAMPAL ATROPHY AND COGNITIVE IMPAIRMENT - REPLY
CONVIT, A; DELEON, MJ; TARSHISH, C; DESANTI, S; RUSINEK, H; GEORGE, AE
1995 APR 15 ;345(8955):992-992, Lancet
— id: 73276, year: 1995, vol: 345, page: 992, stat: Journal Article,

The hippocampus in aging and Alzheimer's disease
de Leon MJ; Convit A; DeSanti S; Golomb J; Tarshish C; Rusinek H; Bobinski M; Ince C; Miller DC; Wisniewski HM
1995 Feb;5(1):1-17, Neuroimaging clinics of North America
The role of imaging in the evaluation of neurodegenerative disorders is summarized. The primary role of imaging is to exclude potentially treatable disorders such as meningioma, extracerebral hematoma, Wernicke's disease, and hypothyroidism. Atrophic changes dominate in the hippocampal region on Alzheimer's disease versus the anterior, frontal, and temporal lobes in Pick's disease. Signal hypointensity in the putamen on T2-weighted spin-echo images favors poorly drug-responsive Parkinson's disease whereas putaminal hyperintensity is observed with Creutzfeldt-Jacob, Wilson's, and Leigh's diseases. As our population ages, a thorough understanding of imaging findings in a geriatric population assumes an increasing importance
— id: 6602, year: 1995, vol: 5, page: 1, stat: Journal Article,

Age-related changes in brain: II. Positron emission tomography of frontal and temporal lobe glucose metabolism in normal subjects
De Santi S; de Leon MJ; Convit A; Tarshish C; Rusinek H; Tsui WH; Sinaiko E; Wang GJ; Bartlet E; Volkow N
1995 Winter;66(4):357-370, Psychiatric quarterly
While many neuropsychological studies have demonstrated age-related performance alterations in tests thought to reflect frontal and temporal lobe function, there is little direct observation and comparison of these hypothesized brain changes in vivo. The cerebral glucose metabolism of frontal, temporal, and cerebellar regions was examined in 40 young (mean = 27.5 +/- 4.9) and 31 elderly (mean = 67.6 +/- 8.8) normal males using PET-FDG. Univariate analysis showed age-related metabolic reductions in all frontal and temporal lobe regions. The reductions ranged from 13%-24% with the greatest changes in the frontal lobes. Multiple regression analyses showed a stronger age relationship with frontal lobe than with temporal lobe metabolism. The dorsal lateral frontal lobe was the region that appears to change most within the frontal lobes. Examination of the temporal lobe showed that age contributed equally to the metabolic variance of both the lateral temporal lobe and hippocampus. These results suggest that age-related metabolic changes exist in both frontal and temporal lobes and that the frontal lobe change is greater
— id: 9454, year: 1995, vol: 66, page: 357, stat: Journal Article,

COMPARISON OF X-RAY MAMMOGRAPHY AND A COMPUTER-ASSISTED MR-IMAGING METHOD FOR DETERMINATION OF FAT-TO-FIBROGLANDULAR TISSUE RATIOS IN THE BREASTS OF WOMEN AGED 20-83 YEARS
LEE, NA; RUSINEK, H; WEINREB, JC; NEWSTEAD, GM; CHANDRA, R; SINGER, CI
1995 NOV ;197(1):311-311, Radiology
— id: 73274, year: 1995, vol: 197, page: 311, stat: Journal Article,

COMPENSATION OF FIELD DISTORTION WITH FERROMAGNETIC MATERIALS
ABELE, MG; RUSINEK, H; BERTORA, F; TREQUATTRINI, A
1994 MAY 15 ;75(10):6990-6992, Journal of applied physics
This paper discusses a technique for improving the homogeneity of the magnetic field in structures of permanent magnets designed for magnetic resonance imaging, achieved by inserting layers of ferromagnetic plates and permanent magnets along the cavity of the structure. The analysis of the field in the magnet is performed using a boundary integral equation method. An example of optimization of the geometry and the amount of the magnetic material is presented
— id: 52435, year: 1994, vol: 75, page: 6990, stat: Journal Article,

Effects of haloperidol challenge on regional cerebral glucose utilization in normal human subjects
Bartlett EJ; Brodie JD; Simkowitz P; Dewey SL; Rusinek H; Wolf AP; Fowler JS; Volkow ND; Smith G; Wolkin A
1994 May;151(5):681-686, American journal of psychiatry
OBJECTIVE: Positron emission tomography and the fluorodeoxyglucose (FDG) method were used to determine the brain's metabolic response to neuroleptic challenge in a normal, disease-free state. METHOD: FDG measurements were obtained before and 12 hours after administration of 5 mg of haloperidol to 12 young normal men. These values were compared with test-retest FDG measures obtained from nine normal male control subjects who received no drug intervention. RESULTS: After haloperidol administration, the haloperidol subjects showed significantly lower glucose utilization in the neocortex, limbic cortex, thalamus, and caudate nucleus but not in the putamen or cerebellum. After adjustment for global effects, significant reductions were still evident in the frontal, occipital, and anterior cingulate cortex, whereas the putamen and cerebellum showed significant increases. CONCLUSIONS: This study, measuring the brain's metabolic response to acute receptor blockade, is a first step in the development of an assay of CNS pharmacological activity. By determining the response to neuroleptic challenge in a normal state, the study establishes a comparison group for determining response to challenge in various psychiatric conditions
— id: 6319, year: 1994, vol: 151, page: 681, stat: Journal Article,

A new method of data acquisition in k-space in magnetic resonance imaging
Chandra R; Rusinek H
1994 ;VII:392-402, Medical imaging. Physics of Medical Imaging (SPIE)
— id: 73284, year: 1994, vol: VII, page: 392, stat: Journal Article,

SELECTIVE MEDIAL AND LATERAL TEMPORAL-LOBE PATHOLOGY IN CASES AT-RISK FOR AD - DIAGNOSTIC ROLE OF PET
DESANTI, S; DELEON, MJ; TARSHISH, C; GOLOMB, J; MCRAE, T; KLUGER, A; RUSINEK, H; CONVIT, A; FOWLER, J; VOLKOW, N
1994 JUL ;15(7):S146-S147, Neurobiology of aging
— id: 52413, year: 1994, vol: 15, page: S146, stat: Journal Article,

Hippocampal atrophy correlates with severe cognitive impairment in elderly patients with suspected normal pressure hydrocephalus
Golomb J; de Leon MJ; George AE; Kluger A; Convit A; Rusinek H; de Santi S; Litt A; Foo SH; Ferris SH
1994 May;57(5):590-593, Journal of neurology neurosurgery & psychiatry
Measurements of hippocampal formation atrophy using MRI have been useful in distinguishing demented patients with a diagnosis of probable Alzheimer's disease from cognitively normal controls. To determine whether there is a similar relationship between hippocampal size and dementia in elderly patients suspected of normal pressure hydrocephalus (NPH), the authors obtained mini-mental status examination (MMSE) scores and MRI measurements of hippocampal size and CSF volume on 16 elderly patients whose severe ventriculomegaly and unexplained gait impairment made NPH a probable diagnosis. Hippocampal size correlated strongly with MMSE score (r = 0.75, p < 0.001); no significant MMSE correlation was found for ventricular CSF volume or extra-ventricular/ventricular CSF ratio. It was concluded that hippocampal atrophy is associated with severe cognitive dysfunction in many elderly patients with a diagnosis of NPH. As a hypothesis for further investigation, the detection of such atrophy may help identify cases where the presence of a pathology of Alzheimer's disease complicates the diagnosis of NPH
— id: 6390, year: 1994, vol: 57, page: 590, stat: Journal Article,

Hippocampal formation size in normal human aging: a correlate of delayed secondary memory performance
Golomb J; Kluger A; de Leon MJ; Ferris SH; Convit A; Mittelman MS; Cohen J; Rusinek H; De Santi S; George AE
1994 May-Jun;1(1):45-54, Learning & memory
Although mild progressive memory impairment is commonly associated with normal human aging, it is unclear whether this phenomenon can be explained by specific structural brain changes. In a research sample of 54 medically healthy and cognitively normal elderly persons (ages 55-87, x = 69.0 +/- 7.9), magnetic resonance imaging (MRI) was used to derive head-size-adjusted measurements of the hippocampal formation (HF) (dentate gyrus, hippocampus proper, alveus, fimbria, subiculum), the superior temporal gyrus (STG), and the subarachnoid cerebrospinal fluid (CSF) (to estimate generalized cerebral atrophy). Subjects were administered tests of primary memory (digit span) and tests of secondary memory with immediate and delayed recall components (paragraph, paired associate, list recall; facial recognition). Separate composite scores for the immediate and delayed components were created by combining, with equal weighting, the subtests of each category. The WAIS vocabulary subtest was used as a control measure for language and intelligence. A highly significant correlation (P < 0.001), independent of age, gender, and generalized cerebral atrophy was found between HF size and delayed memory performance. No significant correlations were found between HF size and primary or immediate memory performance. STG size was not significantly correlated with any of the composite memory variables. These results suggest that HF atrophy may play an important independent role in contributing to the memory loss experienced by many aging adults
— id: 6632, year: 1994, vol: 1, page: 45, stat: Journal Article,

OPTIMIZATION OF MULTILAYERED MAGNETIC-STRUCTURES
ABELE, MG; RUSINEK, H
1993 MAY 15 ;73(10):5446-5448, Journal of applied physics
This paper describes the categories of permanent magnets built with layers of different magnetic properties and determines the distribution of the remanence in the concentric layers that optimize the figure of merit. As an example, the paper shows the optimization of a two-layered structure composed of two materials with vastly different energy product values, such as a ferrite and a NdFeB alloy. The use of lower remanence material as the outer layer significantly increases the efficiency of the magnetic structure
— id: 54130, year: 1993, vol: 73, page: 5446, stat: Journal Article,

FIELD DISTORTION CAUSED BY MAGNETIZATION TOLERANCES OF PERMANENT-MAGNETS
ABELE, MG; RUSINEK, H; BERTORA, F
1993 NOV ;29(6):2908-2910, IEEE transactions on magnetics
Factors contributing to distortion of the field generated by permanent magnets, such as fabrication and material tolerances, are analyzed using the harmonic series expansion of the magnetostatic potential. The power spectrum is influenced by the number of discrete blocks and the number of layers of the magnetic structure. Ferromagnetic plates, acting as spatial filters inserted in the magnetic structure, reduce the distortions due to magnetization tolerances by approximately 60%
— id: 73277, year: 1993, vol: 29, page: 2908, stat: Journal Article,

SHIMMING OF YOKELESS PERMANENT-MAGNETS DESIGNED TO GENERATE UNIFORM-FIELDS
BERTORA, F; TREQUATTRINI, A; ABELE, MG; RUSINEK, H
1993 MAY 15 ;73(10):6864-6866, Journal of applied physics
Recently introduced yokeless permanent magnets are very suitable for generating uniform fields. Practical yokeless magnets must be shimmed or compensated for fabrication and magnetization tolerances. The particular shimming approach described exploits the magnetic transparency of yokeless structures. The method is based on the use of active elements of high-energy-product material. The logic for determining the distribution of active elements is based on measuring the departure from uniformity of the field sampled on a sphere surrounding the region of interest. The magnetic moments of the elements are determined by solving a system of linear equations representing the field generated by active elements on each sampling point
— id: 73278, year: 1993, vol: 73, page: 6864, stat: Journal Article,

Long term study of random noise and signal uniformity in spin-echo brain imaging
Chandra R; Rusinek H
1993 Jul-Aug;20(4):1071-1075, Medical physics
Random noise and MR signal uniformity were analyzed for a period of 9 months using two head coils on a 1.5 T commercial imager. Signal response from a cylindrical phantom filled with a 0.1 mmol/L CuSO4 solution was incorporated in a correction scheme and the effect of correction on uniformity and accuracy of tissue volume determination was measured. There was little change in random noise (CV < 5%) and image uniformity (CV < 15%) over the time of the study. The uniformity in a 130 cm2 region was 4% for a double saddle coil and 5.3% for a mirror coil. After correction, uniformity was improved to 1.1% for the double saddle coil and 1.2% for the mirror coil. In a 40 cm2 central region the uniformity was approximately three times better than in the 130 cm2 region. A second phantom, mimicking the relaxation times of CSF and the brain, consisted of saline encapsulated in vials of volume ranging from 35.6 ml to 249.6 ml and placed in a 0.1 mmol/L solution of MnCl2. Uniformity correction reduced the average error in volume measurement from 8.6% to 6.1%
— id: 7883, year: 1993, vol: 20, page: 1071, stat: Journal Article,

3-DIMENSIONAL PET-PET BRAIN IMAGE REGISTRATION AND ENHANCEMENT OF THE SIGNAL-NOISE RATIO IN FUNCTIONAL PATTERNS - ANALYSIS OF FUNCTIONAL PATTERN ENHANCEMENT DURING A MOTOR TASK
LEVY, AV; BERTOLLO, D; DHAWAN, A; ARATA, L; BARTLETT, E; RUSINEK, H; VOLKOW, N; BRODIE, JD
1993 MAY ;34(5):P40-P40, Journal of nuclear medicine
— id: 73279, year: 1993, vol: 34, page: P40, stat: Journal Article,

Variables affecting pulmonary nodule detection with computed tomography: evaluation with three-dimensional computer simulation
Naidich DP; Rusinek H; McGuinness G; Leitman B; McCauley DI; Henschke CI
1993 Fall;8(4):291-299, Journal of thoracic imaging
To meaningfully evaluate factors determining the overall accuracy of computed tomography (CT) for identifying pulmonary nodules, computer-generated nodules were superimposed on normal CT scans and interpreted independently by three experienced chest radiologists. Variables evaluated included nodule size, shape, number, density, location, edge characteristics, and relationship to adjacent vessels, as well as technical factors, including slice thickness and electronic windowing. The overall sensitivity in identifying nodules was 62% and the specificity was 80%. On average, the observers identified 56, 67, and 63% of nodules on 1.5-, 5-, and 10-mm-thick sections, respectively (p = 0.037). Nodules were more difficult to identify on 1.5-mm-thick sections. On average, observers identified 1, 48, 82, and 91% of nodules < 1.5, < 3, < 4.5, and < 7 mm in diameter, respectively (p < 0.001). Other factors that made a significant contribution (p < 0.01) in identifying nodules, as determined by linear discriminant function analysis, included nodule location, angiocentricity, and density. We concluded that computer-generated nodules can be used to assess a large number of imaging variables. We anticipate that this approach will be of considerable utility in assessing the accuracy of interpretation of a wide range of pathologic entities as well as in optimizing three-dimensional scan protocols within the thorax
— id: 56568, year: 1993, vol: 8, page: 291, stat: Journal Article,

Brain tissue volume measurement from magnetic resonance imaging. A phantom study
Rusinek H; Chandra R
1993 Oct;28(10):890-895, Investigative radiology
RATIONALE AND OBJECTIVES. The authors appraised the accuracy of a method for brain volume measurement from magnetic resonance images and evaluated the effects of the acquisition matrix, slice thickness, and tissue sampling on the measurement error. METHODS. The method uses two magnetic resonance imaging sequences to account explicitly for partial volume effects. The accuracy was measured with one-, two-, and three-compartmental phantoms that mimic the relaxation properties of brain tissues. The sensitivity of the method to section thickness was measured by repeated scans of human brain. RESULTS. Using a strongly T2-weighted sequence and two-compartmental phantoms, the average error was 5%, with 3% error for phantoms larger than 90 mL. In the three-compartmental phantoms the error varied from 2% to 7%. Varying the section thickness from 5 to 10 mm on three-compartmental phantoms and from 2.5 to 10 mm in the human brain did not significantly affect compartmental volumes. CONCLUSIONS. The experimental study validates the feasibility of monitoring localized volume changes in a three-compartmental model
— id: 6503, year: 1993, vol: 28, page: 890, stat: Journal Article,

Principal axes and surface fitting methods for three-dimensional image registration
Rusinek H; Tsui WH; Levy AV; Noz ME; de Leon MJ
1993 Nov;34(11):2019-2024, Journal of nuclear medicine
We evaluated the effect of the image acquisition parameters on the accuracy of the principal axes and surface-fitting techniques for three-dimensional image registration. Using two types of phantom objects, MR brain image and a mathematically defined ellipsoid, we simulated pairs of scans with known acquisition parameters, including longitudinal coverage, magnitude of mis-registration, number of sections and section thickness. Both methods are sensitive to the systematic deformation of contours. The principal axes method is also sensitive to incomplete scan coverage and to the x-axis and y-axis misangulation. Both methods are insensitive to the number of sections, section thickness and the number of points per section. Surface fitting performed well without user supervision. There is no need for routine inclusion of the scaling factors as search parameters. The results confirm the feasibility of three-dimensional multimodality registration of brain scans with accuracy 1-2 mm, with surface fitting being the method of choice
— id: 6504, year: 1993, vol: 34, page: 2019, stat: Journal Article,

Fast surface-fitting algorithm for 3-D image registration
Tsui W-H; Rusinek H; Van Gelder P; Lebedev S
1993 ;1898:11-20, Medical imaging. Image processing (SPIE)
— id: 73288, year: 1993, vol: 1898, page: 11, stat: Journal Article,

FIELD COMPUTATION IN PERMANENT-MAGNETS
ABELE, MG; RUSINEK, H; BERTORA, F
1992 JAN ;28(1):931-934, IEEE transactions on magnetics
This paper presents a method of field computation in permanent magnets designed to generate a uniform field in the region of interest. The computation technique is particularly suitable to magnetic structures used in magnetic resonance imaging (MRI). The method is applied to the design of yokeless, yoked, and hybrid prismatic magnetic structures. In particular, it is applied to the correction of the field inhomogeneity of open magnets by means of a modulation of the magnetic material and by the introduction of high permeability materials
— id: 52085, year: 1992, vol: 28, page: 931, stat: Journal Article,

Protruding aortic atheromas predict stroke in elderly patients undergoing cardiopulmonary bypass: experience with intraoperative transesophageal echocardiography
Katz ES; Tunick PA; Rusinek H; Ribakove G; Spencer FC; Kronzon I
1992 Jul;20(1):70-77, Journal of the American College of Cardiology
Protruding atheromas of the aortic arch identified by transesophageal echocardiography have been implicated as a cause of stroke in elderly patients. One hundred thirty patients greater than or equal to 65 years of age were studied with intraoperative transesophageal echocardiography to detect aortic arch protruding atheromas and determine if these patients were at higher risk for perioperative stroke. Protruding atheromas were identified in 23 (18%) of 130 patients. In 19 (83%) of these 23 patients, palpation of the aortic arch at operation did not identify significant abnormalities. Five patients (4%) had perioperative stroke. Logistic regression identified aortic arch atheroma as the only historical or procedural variable that was predictive of stroke (odds ratio 5.8, 95% confidence interval 1.2 to 27.9, p less than 0.03). A history of peripheral or cerebrovascular disease, presence of aortic calcification, cardiac risk factors, age and duration of cardiopulmonary bypass did not predict stroke. In contrast, patients with protruding atheromas with mobile components were at highest risk. There were 3 (25%) of 12 patients with a mobile atheroma who had a stroke versus 2 (2%) of 118 patients without a mobile atheroma (chi-square = 10.3, p = 0.001). Displacement and detachment of the frail, protruding atherosclerotic material by aortic arch cannulation or by the high pressure jet emanating from the cannula tip may play an important role in the creation of embolization and stroke
— id: 13531, year: 1992, vol: 20, page: 70, stat: Journal Article,

3-DIMENSIONAL REGISTRATION OF MULTIMODALITY MEDICAL IMAGES USING THE PRINCIPAL AXES TECHNIQUE
MOSHFEGHI, M; RUSINEK, H
1992 JUL ;47(2):81-97, Philips journal of research
Registration of volumetric images from different medical imaging modalities is performed by matching surfaces using the principal axes technique. Translation, rotation, and scaling transformations are calculated by eigenvalue analysis of the scatter matrix. After applying the transformations, reslicing along comparable planes is carried out. The method is applied to a clinical case of X-ray computed tomography (CT) and magnetic resonance imaging (MRI) brain scans. The accuracy, measured as the distance between recognizable reference points in the registered CT and MRI slices, was 1.5 mm. Visual confirmation of the quality of the registration is provided by compositing the registered images. The method is simple to implement and computationally efficient; calculation of the transformation takes less than 1 s of computer time. This method requires full scan coverage in both scans and assumes local distortions are not present. Potential applications of this technique include radiation therapy, Surgical planning, functional/anatomical correlation, and retrospective studies
— id: 51931, year: 1992, vol: 47, page: 81, stat: Journal Article,

USE OF MAGNETOENCEPHALOGRAPHY AND MR IMAGING TO LOCALIZE NORMAL AND PATHOLOGICAL HUMAN BRAIN-FUNCTION
RIBARY, U; MOGILNER, A; JOLIOT, M; VOLKMANN, J; RUSINEK, H; LLINAS, RR
1992 NOV ;185(5):199-199, Radiology
— id: 105129, year: 1992, vol: 185, page: 199, stat: Journal Article,

Segmentation of brain tissue from magnetic resonance images
Chandra R; Rusinek H
1991 ;1445(V):133-144, Medical imaging. Image processing (SPIE)
— id: 73285, year: 1991, vol: 1445, page: 133, stat: Journal Article,

GRAPHICS APPLIED TO MEDICAL IMAGE REGISTRATION
Maguire, GQ; Noz, ME; Rusinek, H; Jaeger, J; Kramer, EL; Sanger, JJ; Smith, G
1991 Mar;11(2):20-27, IEEE computer graphics & applications
— id: 32223, year: 1991, vol: 11, page: 20, stat: Journal Article,

Alzheimer disease: measuring loss of cerebral gray matter with MR imaging [see comments]
Rusinek H; de Leon MJ; George AE; Stylopoulos LA; Chandra R; Smith G; Rand T; Mourino M; Kowalski H
1991 Jan;178(1):109-114, Radiology
The distributions of the cerebral gray matter, the white matter, and the intracranial cerebrospinal fluid (CSF) were measured in 14 patients with Alzheimer disease (AD) and in 14 healthy control subjects. The measurements, derived from two specifically designed magnetic resonance inversion-recovery sequences, compensate for partial signal averaging. The percentage of the gray matter in the brains of AD patients (44.9% +/- 4.4) was significantly lower than in control subjects (50.2% +/- 3.2). The most significant reduction (P less than .001) occurred in the temporal lobes (13.8%) and a central region (12.8); the reduction in frontal lobe (11.2%) and occipital lobe (9.2%) was also statistically significant (P less than .01). There was an increase in the CSF volume in the temporal, occipital, and frontal regions; no region showed a significant difference in the white matter content. The findings of diffuse changes and temporal lobe involvement in AD are consistent with pathologic observations of cortical cell loss
— id: 8260, year: 1991, vol: 178, page: 109, stat: Journal Article,

OPTIMUM DESIGN OF YOKELESS PERMANENT-MAGNETS
Abele, MG; Rusinek, H
1990 May 1;67(9):4644-4646, Journal of applied physics
— id: 32062, year: 1990, vol: 67, page: 4644, stat: Journal Article,

Analysis of random noise, coil inhomogeneity, and ghost artifacts in spin echo imaging on a 1.5 T commercial magnetic resonance imager
Chandra R; Rusinek H
1990 ;1245:72-80, Proceedings of SPIE (The International Society for Optical Engineering)
— id: 73289, year: 1990, vol: 1245, page: 72, stat: Journal Article,

A comparison of two approaches to three-dimensional imaging of craniofacial anomalies
Rusinek H; Karp NS; Cutting CB
1990 May;3(2):81-88, Journal of digital imaging
Volume-based and surface-based algorithms for three-dimensional rendering of computed tomography (CT) scans of the human skull were compared in patients with craniofacial anomalies. Both methods were applied to a selected sample of 12 clinical CT studies. The number of sections ranged from 24 to 72 and the section thickness from 1.5 to 6.0 mm. Volume renderings were more prone to interpolation artifacts but captured the anatomy in greater detail. The sites of closed cranial sutures, visualized using the volume technique, were not demonstrated using the specific surface rendering technique used in this study. In both techniques the areas of thin bone appeared as gaps
— id: 33296, year: 1990, vol: 3, page: 81, stat: Journal Article,

COMPENSATION OF NON-UNIFORM MAGNETIC-PROPERTIES OF COMPONENTS OF A YOKELESS PERMANENT-MAGNET
Abele, MG; Chandra, R; Rusinek, H; Leupold, HA; Potenziani, E
1989 Sep;25(5):3904-3906, IEEE transactions on magnetics
— id: 31619, year: 1989, vol: 25, page: 3904, stat: Journal Article,

Cerebral cortical and white matter reactivity to carbon dioxide
Reich T; Rusinek H
1989 Apr;20(4):453-457, Stroke
We measured cerebrovascular reactivity to carbon dioxide in the cerebral cortex and the subcortical white matter of 12 healthy adult volunteers (four young subjects aged 21-24, four middle-aged subjects aged 34-40, and four elderly subjects aged 62-85 years). Blood flow was computed from the concentration history of xenon-133 in the volume of interest measured with an ultrapure germanium detector array. End-tidal PaCO2 ranged from 35.4 to 42.6 mm Hg. The mean +/- SD baseline blood flows in the cerebral cortex were 60 +/- 7, 51 +/- 9, and 33 +/- 4 ml/100 cm3/min in the young, the middle-aged, and the elderly subjects, respectively; the corresponding subcortical white matter baseline blood flows were 21 +/- 1, 22 +/- 3, and 16 +/- 5 ml/100 cm3/min. Mean +/- SD cerebrovascular reactivities to carbon dioxide in the cerebral cortex were 2.03 +/- 0.58, 1.36 +/- 0.41, and 0.72 +/- 0.19 ml/100 cm3/min/mm Hg PaCO2 for the young, the middle-aged, and the elderly subjects, respectively; the corresponding reactivities in the subcortical white matter were 0.69 +/- 0.11, 0.59 +/- 0.17, and 0.36 +/- 0.41 ml/100 cm3/min/mm Hg PaCO2. Blood flow and cerebrovascular reactivity in the cerebral cortex of the young subjects were significantly higher than those for white matter and significantly higher than those in the elderly subjects (p less than 0.001). Age vs. blood flow (for the cortex) and age vs. cerebrovascular reactivity (for both cortical gray and subcortical white matter) also showed significant linear correlation (p less than 0.05). However, the age-related changes in white matter blood flow and cerebrovascular reactivity were slow, and the differences among the age groups were not statistically significant
— id: 10692, year: 1989, vol: 20, page: 453, stat: Journal Article,

Three-dimensional rendering of medical images : surface and volume approach
Rusinek H; Karp N; Cutting C
1989 ;1091(III):204-211, Medical imaging (SPIE)
— id: 73283, year: 1989, vol: 1091, page: 204, stat: Journal Article,

Interactive graphic editor for analysis and enhancement of medical images
Rusinek H; Mourino M
1989 Aug;22(4):328-338, Computers & biomedical research
We have developed an interactive graphic editor to define subregions within a volume of medical images arranged in serial sections. The editing methods include tracing and automatic growing of connected components defined by the gray level range. The editor performs a statistical analysis of the signal contained in each subvolume and is used in studies of magnetic resonance (MR) signal in medical images. The graphic editor is also used for creating 3D views from MR images based on the new volume-rendering algorithm. The editor transforms the volume of images by remapping their gray levels and by multiplanar cuts. The ability to suppress regions having the same signal intensity as the region of interest is important in generating an unobstructed view of the anatomical structures
— id: 10524, year: 1989, vol: 22, page: 328, stat: Journal Article,

Volumetric rendering of MR images
Rusinek H; Mourino MR; Firooznia H; Weinreb JC; Chase NE
1989 Apr;171(1):269-272, Radiology
The authors developed new techniques for three-dimensional display of magnetic resonance (MR) images that preserve soft-tissue definition, are fully automatic, and work with routinely used section thicknesses. MR images are segmented, selectively enhanced, and displayed by means of a volumetric rendering algorithm. These techniques were used to illustrate normal anatomy of the brain, knee, and liver. Three-dimensional rendering of balanced spin-echo images shows the ventricles and extracerebral veins and of T1-weighted images, the sulci and gyri. The large hepatic and portal vessels can be seen with these enhancement techniques. Three-dimensional views of the knee reveal articular surfaces of the tibia and clearly depict menisci and posterior and anterior cruciate ligaments. These techniques make it possible to image multiple soft tissues simultaneously while preserving the detail contained in the original images. Three-dimensional presentation of complex, overlapping anatomic regions is helpful in surgical planning and should lead to improved diagnosis
— id: 10670, year: 1989, vol: 171, page: 269, stat: Journal Article,

Generation of tissue volume imaging from magnetic resonance scans
Mourino M; Moore A; Rusinek H
1988 ;914(II):11274-1281, Medical imaging (SPIE)
— id: 73282, year: 1988, vol: 914, page: 11274, stat: Journal Article,

Multicompartmental analysis of tracer clearance and its application to cerebral blood flow measurement
Rusinek, H
1986 Oct;19(5):468-480, Computers & biomedical research
A new algorithm for computing cerebral blood flow is shown to overcome compartmental slippage and unstability problems associated with the conventional bicompartmental analysis. The tracer clearance curve is decomposed into a nonnegative linear combination of predetermined flow components. A weighted average of flows above (below) a fixed threshold yields the gray (white) matter flow. The accuracy and the stability of the new algorithm are analyzed by Monte-Carlo simulations, determining the effect of factors such as random error in tracer concentration, gray-white flow difference, tissue content of gray matter, and end-fit time. While the new algorithm requires 50-100% more CPU time and memory space than the bicompartmental method, its accuracy and stability is superior, especially as the conditions of the measurement deteriorate. The results suggest that more than twofold error reduction in measuring the blood flow in pathological brain tissue is possible
— id: 73262, year: 1986, vol: 19, page: 468, stat: Journal Article,

THE EFFECT OF VESSEL EDGE DEFINITION ON STATISTICAL ERRORS IN DSA MEASUREMENTS
RUSINEK, H; SLATER, J; GLASSMAN, E
1986 OCT ;74(4):484-484, Circulation
— id: 41341, year: 1986, vol: 74, page: 484, stat: Journal Article,

Cerebral distribution of 133-Xe and blood flow measured with high purity germanium
Reich, T; Rusinek, H; Youdin, M; Clagnaz, M
1985 Jan-Feb;16(1):92-101, Stroke
Distribution of cerebral blood flow was measured with an array of 200 ultra-pure germanium radiation detectors and 133-Xe by inhalation. The array 'sees' the head as a composite of different subvolumes and enables measurement of the concentration history of tracer every 1-10 sec in each subvolume simultaneously. Subvolume mean flows, (fm), and partition coefficients, lambda m, are derived by compartmental analysis of tissue concentration washout curves. Errors from 'cross talk,' scalp radiation, 'look through,' and assumed partition coefficients are eliminated. Average fm adjusted for 40 mm Hg PACO2 in 14 cortical subvolumes (7 right, 7 left) of four normal 21-24 year old controls ranged from 50 to 60 ml/100 cc tissue/min, and lambda m ranged from 0.97 to 1.14. Average fm and lambda m in white matter was 24 ml/100 cc/min and 1.42 - 1.14 respectively. During CO2 inhalation, right and left hemispheric fm increased 6.4% and 5.7%/mm Hg respectively, whereas white matter fm increased 2.2% and 3.4% mm Hg respectively. There was no systematic difference between front and back or dominant vs non-dominant sides. Three 73-84 year old controls had reduced fm and CO2 reactivity in all subvolumes, lambda m was in the same range as in younger controls. Two patients with intracranial cerebrovascular disease showed excellent localization of ischemic subvolumes. One patient with asymptomatic unilateral 98% stenosis of the internal carotid artery had a similar distribution of blood flow in both hemispheres
— id: 73263, year: 1985, vol: 16, page: 92, stat: Journal Article,

COMPUTER MODELING AND ANALYSIS OF SPECT INSTRUMENTS
RUSINEK, H
1985 OCT ;26(5):P51-P51, Journal of nuclear medicine
— id: 73280, year: 1985, vol: 26, page: P51, stat: Journal Article,

Multicounter with buffered output
Harrison, B.S.; Rusinek, H.; Reich, T.
1981 ;87(1):435-437, IEEE frontiers of engineering in health care
Describes a multicounter unit with buffers for storage and transmission of collected counts to the host computer. The system is highly flexible, inexpensive, and able to communicate with computers without direct memory access capability. A prototype has been built at New York University Medical Center for use with a 200-element detector array for measuring the 3-D distribution of cerebral blood flow. The multicounter will free the computer from continuous scanning of the detectors to perform on-line display and storage of collected data. An important feature of the unit is that its proper operation can be quickly verified with the aid of the host computer and detailed diagnosis obtained in case of malfunction
— id: 98871, year: 1981, vol: 87, page: 435, stat: Journal Article,

MULTICOUNTER WITH BUFFERED OUTPUT
HARRISON, BS; RUSINEK, H; REICH, T
1981 OCT ;28(8):600-600, IEEE transactions on biomedical engineering
— id: 73281, year: 1981, vol: 28, page: 600, stat: Journal Article,

An ultrapure germanium detector array for quantitating three-dimensional distribution of a radionuclide: a study of phantoms
Rusinek, H; Reich, T; Youdin, M; Clagnaz, M; Kolwicz, R
1980 Aug;21(8):777-782, Journal of nuclear medicine
A new stationary 200-element ultrapure germanium (HPGe) array has been tested for accuracy and sensitivity in quantitating the distributed concentration of single-gamma-emitting radionuclides in phantoms approximating the size of the human brain. The phantoms consisted of 42 blocks of 39.1 cm3 average volume. Fourteen different permutations were studied. The concentrations in the blocks varied from 0i to 4.64 muCi/cm3. This first-generation instrument makes it possible to reconstruct the distributed concentration with a mean relative error of 8.3% at 200,000 counts per sample (1,000 counts/detector), and has sensitivities of 6,200 and 12,000 cps, respectively, for 1 muCi/cm3 of Xe-133 and Tc-99. The reconstruction algorithm is based on the conjugate gradient method of solving the set of linear equations that account for geometric, attenuation, and scatter factors. The results have implications for measuring the distribution of the partition coefficients, blood flow, blood volume, and concentration of tracers emitting single gamma photons in 42 anatomic subvolumes (30 cm3 average) of the entire brain simultaneously
— id: 73264, year: 1980, vol: 21, page: 777, stat: Journal Article,

Reconstruction of isotope distribution in the brain: error analysis for instrument design
Rusinek, H; Youdin, M; Reich, T
1978 Dec;6(4):399-412, Annals of biomedical engineering
— id: 73265, year: 1978, vol: 6, page: 399, stat: Journal Article,

4-DIMENSIONAL RECONSTRUCTION OF RADIOISOTOPIC ACTIVITY IN BRAIN
REICH, T; YOUDIN, M; RUSINEK, H
1977 ;26(1):151-151, Transactions of the American Nuclear Society
— id: 39956, year: 1977, vol: 26, page: 151, stat: Journal Article,