Research Summary Diffusion-weighted imaging (DWI) is a remarkable magnetic resonance imaging (MRI) tool that provides sensitivity to tissue microstructure and water mobility on the micron scale and embeds this information as contrast in macroscopic images of the human body. In this approach, water molecules become reporters of their host tissue microenvironment, whether it be restricting or driving their local motion due to native or pathological processes. The applications of this technique are as varied as the behavior of water within biological tissue, and with the proper acquisition and analysis framework, can include diagnostic and prognostic biomarkers of tissue function across a range of disorders. My research group works at the translational interface between technical development and clinical application of DWI, both providing new imaging / analysis tools and applying them in clinical populations to determine their optimum benefit.
In the area of breast cancer, conventional DWI is an established marker of aggressive cellularity through its restriction of apparent water diffusion. Our implementation of the intravoxel incoherent motion (IVIM) approach, however, provides sensitivity not only to cellularity but also separately to the often concomitant growth of neovasculature (angiogenesis) that supports tumors? hyperactive growth. We are also exploring the connection of these IVIM biomarkers to histological microstructural metrics, systemic anomalies like interstitial fluid pressure, and hormonal prognostic factors to maximize their potential in both diagnosis and prediction of treatment response.
Skeletal muscle is another system where microstructure heavily impacts macroscopic function. We apply diffusion tensor imaging (DTI)?a technique sensitive to tissue directionality through anisotropic water restriction-- to skeletal muscle pathologies such as chronic exertional compartment syndrome, in order to improve detection as well as understand the biophysical mechanism of this debilitating disorder. However, since the kinematics of muscle motion are often key to diagnosis, we are simultaneously developing a new approach to muscle DTI. In this revolutionary development, a Multiple Echo Diffusion Tensor Acqusition Technique (MEDITATE), the required variation of the diffusion sensitization (both magnitude and direction) is compressed to very few scans through the use of multiple echoes. This acceleration may then allow DTI microstructural metrics to be captured dynamically, during muscle exertion.
Research Interests Technical development:Diffusion-weighted imaging (DWI), intravoxel incoherent motion (IVIM) imaging, diffusion tensor imaging (DTI), dynamical DTI, time-dependent diffusion, ultra-high field imaging.
Oncological imaging: multi-parametric assessment of tumor microenvironment, predicting treatment response, interstitial fluid pressure.
Muscle imaging: microscopic correlates of macroscopic insult, chronic exertional compartment syndrome.
Research Keywords diffusion imaging, DWI, DTI, IVIM, DKI, interstitial fluid pressure, dynamical DTI