Is Water Diffusion Restricted In Human Brain White-Matter - An Echo-Planar Nmr Imaging Study

摘要: Water diffusion is extremely anisotropic in brain white matter, depending on myelin fiber orientation. A suggested, but unproven cause of anisotropy that, the direction transverse to fibers, axonal water prevented by presence sheath. We found, however, using an ultra-fast nuclear magnetic resonance imaging technique, that dependence coefficient time does not support model restriction impenetrable barriers. These results, which were obtained non-invasively vivo human brain, imply diffuses with a measurable rate across fibers.