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 and dermatomyositis, in order to improve detection as well as understand the biophysical mechanism of these debilitating disorders. 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.
Finally, water transport in renal tissue is a complex mixture of blood flow, tubular flow, and random motion in tissue that act in concert to enable kidney function. We are applying advanced diffusion MRI tools (DTI, IVIM) both alone and in joint analysis, to parse out processes of perfusion, tubular flow, and microstructure as they impact healthy kidney function and its decline with chronic disease or acute surgical shock. Such quantitative and noninvasive data may prove invaluable in the management of renal disease and (as in the breast) renal cancer.
Associate Professor, Department of Radiology
PhD from Northwestern University
Fellowship, Northwestern University Radiology, Postdoctoral Fellowship
Fellowship, Schlumberger-Doll Research, Postdoctoral Fellowship
Magnetic resonance in medicine. 2016 Oct 25; ?-?
NMR in biomedicine. 2016 Oct 7; 30(3):?-?
Journal of magnetic resonance imaging. 2016 Sep 30; 45(2):337-355
Journal of magnetic resonance imaging. 2016 Sep; 44(3):521-540
European radiology. 2016 Aug; 26(8):2547-2558
Clinical nuclear medicine. 2016 Aug; 41(8):e355-e361
Journal of magnetic resonance imaging. 2016 Jul 21; 45(1):84-93