Biosketch / Results /
Glyn JohnsonAdjunct Associate Professor, Department of Radiology
MRI Assessment of Tumor Hemodynamics
Angiogenesis, the creation of new blood vessels, is characteristic of solid tumors and crucial for their development. Accurate quantification of angiogenesis allows differentiation of tumors from non-malignant lesions, differentiation of tumors of different types and monitoring of treatment.
Improved methods of monitoring angiogenesis by dynamic, contrast enhanced magnetic resonance imaging are being developed. A series of images is acquired at one second intervals during the injection of a bolus of contrast agent. Tissue contrast agent concentration can then be calculated from changes in image intensity during bolus passage through the tumor. Vascular volume and vascular permeability can then be calculated from the concentration-time curves.
It has been found that MRI measurements of vascular volume and permeability can be used to differentiate a wide range of non-malignant lesions from tumors despite similar appearance on conventional MRI, to grade tumors and to monitor the efficacy of antiangiogenic treatment.
Functional Lung Imaging
Conventional MRI of water protons provides very little information on the lung which consists mostly of air spaces. However, novel imaging methods have recently been developed that form images of inhaled hyperpolarized helium. Novel methods of using helium MRI to measure lung function as well as demonstrate lung anatomy are being developed.
Research KeywordsMRI pulse sequence development, MRI measurement of tumor hemodynamics, functional MRI of brain tumors, MRI of lung function
Minimization of errors in biexponential T measurements of the prostate
Gilani, Nima; Rosenkrantz, Andrew B; Malcolm, Paul; Johnson, Glyn. Minimization of errors in biexponential T measurements of the prostate. Journal of magnetic resonance imaging. 2015 Oct;42(4):1072-1077 (1473442)
Intravascular contrast agent T(2) (*) relaxivity in brain tissue
Patil, Vishal; Jensen, Jens H; Johnson, Glyn. Intravascular contrast agent T(2) (*) relaxivity in brain tissue. NMR in biomedicine. 2013 Apr;26(4):392-399 (378682)
DeltaR2 (*) gadolinium-diethylenetriaminepentacetic acid relaxivity in venous blood
Patil, Vishal; Johnson, Glyn. DeltaR2 (*) gadolinium-diethylenetriaminepentacetic acid relaxivity in venous blood. Magnetic resonance in medicine. 2013 Apr;69(4):1104-1108 (255172)
Analytical derivation of the b matrix of a time-efficient isotropic diffusion weighting gradient waveform
Trampel, Robert; Johnson, Glyn. Analytical derivation of the b matrix of a time-efficient isotropic diffusion weighting gradient waveform. Medical physics. 2013 Mar;40(3):032301-032301 (823262)
USE OF MULTIVOXEL DSC-MRI PERFUSION DATA IN STEREOTACTIC-GUIDED GLIOMA SURGERY AND CORRELATION WITH TUMOR PATHOLOGY
Parker, Erik; Fatterpekar, Girish; Raz, Eytan; Narayana, Ashwatha; Johnson, Glyn; Placantonakis, Dimitris; Zagzag, David. USE OF MULTIVOXEL DSC-MRI PERFUSION DATA IN STEREOTACTIC-GUIDED GLIOMA SURGERY AND CORRELATION WITH TUMOR PATHOLOGY [Meeting Abstract]. Neuro-oncology. 2012 OCT;14 6 6:125-125 (204992)