Wang Zhan1, Wanyong Shin2,3, Xiujuan Geng3, Hong Gu3, Yihong Yang3
1Radiology & Medical Imaging, University of California, San Francisco, San Francisco, CA, United States; 2Imaging Institute, Cleveland Clinic, Cleveland , OH, United States; 3Neuroimaging Branch, National Institute on Drug Abuse, Baltimore, MD, United States
The histological mechanism for DTI index (FA/MD) changes is still poorly understood. It remains unclear to what extent the variations of FA measurements should be explained by the intra-voxel white matter (WM) tissue fraction rather than the underlying WM integrity. This study aims to identify the correlations between DTI indices and tissue fractions across subjects. Our data indicated that significant correlations between DTI indices and tissue fractions do exist in selective regions, including thalamus and superior frontal lobes. This result suggests the need to consider the effects of tissue fraction variations for a group DTI analysis in those correlation-sensitive regions.