Chunlei Liu1, 2, Aiming Lu3
1Brain Imaging and Analysis Center, Duke University, Durham, NC, United States; 2Department of Radiology, Duke University, Durham, NC, United States; 3Center for MR Research, University of Illinois Medical Center, Chicago, IL, United States
This study found that sodium MRI exhibits nearly an order of magnitude larger susceptibility compared to proton. In sodium MRI, the typical gray and white matter susceptibility contrast is absent. While white matter appears largely paramagnetic, some regions may appear diamagnetic due to intravoxel phase wraps caused by the unusually large susceptibility. Our data further indicate a potentially large susceptibility gradient between extra- and intracellular space as sodium resides primarily in the extracellular space. Measuring susceptibility based on sodium MRI may provide additional insights into sub-cellular susceptibility distribution and the complex mechanisms involved in tissue susceptibility contrast