1Brain Imaging and Analysis Center, Duke University, Durham, NC, United States; 2Radiology, Duke University, Durham, NC, United States
Magnetic susceptibility difference between gray and white matter results in strong phase contrast at high magnetic field strength. We report, for the first time, a surprising observation of tissue-level magnetic susceptibility anisotropy in central nervous system (CNS). Specifically, we found that susceptibility of the white matter exhibits strong orientation dependence. Such orientation variation is extensive throughout the white matter area, but is relatively weak in the gray matter. We anticipate that imaging this anisotropy will provide a unique contrast that is unknown previously. In addition, it will provide a novel tool to further quantify the substructures of the CNS.