The goal of my research is to understand diffusion physics in biological systems and utilize diffusion MRI to elucidate disease mechanisms, facilitate early diagnoses, and identify optimal treatments.  To achieve this goal, my research program focuses on developing quantitative microstructure imaging techniques, assessing the sensitivities of these microstructural measurements in neurologic disorders of the human brain, and validating their specificities with histological analysis of animal models and human post-mortem tissue.  The significance of my research is applicable to any disorder in which alterations of diffusion play an important role in detecting the underlying pathophysiologic mechanisms.   

My earlier work focused on developing advanced and efficient diffusion encoding with fixed diffusion time for clinical MRI scanners.  In 2007, we proposed Hybrid Diffusion Imaging (HYDI) with 5 diffusion-weighting shells and high-angular-resolution diffusion encoding with 120 directions. Using the HYDI acquisition, I initially studied the microstructural changes of white matter inferred by the q-space analytic approach on a population of normal aging. Recently, my lab and I continued to investigate axonal density and orientation dispersion information of normal aging using diffusion compartmental modeling.

My other research direction is to break the barriers of diffusion imaging in medicine. To this end, I started developing affordable high-resolution diffusion imaging and optimizing time-varying diffusion MRI pulse sequences tailored for the human brain in clinical scanners.  In 2016, we proposed a fast high-resolution diffusion MRI technique, rotating single-shot acquisition (RoSA).

In addition to Aging and Alzheimer’s disease, mild traumatic brain injury is also one of my research interests.  We study microstructural changes of brain white matter in mild traumatic brain injury and sport related brain injury (i.e., concussion) in college athletes. My laboratory is also involved in studies to understand the underlying micro-mechanisms of multiple sclerosis and to identify its imaging biomarkers.