Noam Shemesh1, Evren zarslan2, Amnon Bar-Shir3, Peter J. Basser2, Yoram Cohen1
1School of Chemistry, Tel Aviv University, Tel Aviv, Israel; 2Section on Tissue Biophysics and Biomimetics, NICHD, National Institutes of Health, Bethesda, MD, United States; 3Chemistry Department, Tel Aviv University, Tel Aviv, Israel
White-matter voxels which are contaminated with CSF or water diffusing in perpendicular crossing fibers constitute systems in which free and restricted diffusion are superimposed. To study the microstructural information that can be obtained in such settings, we prepared a bi-compartmental phantom in which free water (Gaussian diffusion) are superimposed with water in microcapillaries (restricted diffusion). Both single- and double-PFG experiments were conducted. We find that at low q-values, the signal arising from free water masks that of restricted diffusion and that microstructural information can only be obtained at higher q-values. We also applied these findings to a crossing fibers phantom.