Alexandru Vlad Avram1, 2, Arnaud Guidon2, 3, Wei Li3, Chunlei Liu3, 4, Allen W. Song3, 4
1Section on Tissue Biophysics and Biomimetics, NICHD, National Institutes of Health, Bethesda, MD, United States; 2Biomedical Engineering Department, Duke University, Durham, NC, United States; 3Brain Imaging and Analysis Center, Duke University Medical Center, Durham, NC, United States; 4Radiology Department, Duke University Medical Center, Durham, NC, United States
We investigate the contribution of the nuclear paramagnetic susceptibility to the frequency shifts between brain tissues in the 3D SPGR experiment and its dependence on sequence parameters. Our findings indicate that, depending on sequence parameters, differences in steady state nuclear magnetization between gray and white matter (WM) and cerebrospinal fluid and WM can result in both paramagnetic and diamagnetic frequency shifts within a range of a few parts per billion. We hope that our preliminary results help design improved protocols for quantitative mapping of iron and myelin concentrations and for investigating the contrast mechanism underlying phase and susceptibility imaging.