What dominates the time dependence of diffusion transverse to axons: Intra- or extra-axonal water?

ABSTRACT: Brownian motion of water molecules provides an essential length scale, the diffusion length, commensurate with cell dimensions in biological tissues. Measuring the diffusion coefficient as a function of diffusion time makes in vivo diffusion MRI uniquely sensitive to the cellular features about three orders of magnitude below imaging resolution. However, there is a longstanding debate, regarding which contribution - intra- or extra-cellular - is more relevant in the overall time-dependence of the MRI-derived diffusion metrics. Here we resolve this debate in the human brain white matter. By varying not just the diffusion time, but also the gradient pulse duration of a standard diffusion MRI sequence, we identify a functional form of the measured time-dependent diffusion coefficient transver

SUBMITTER: Lee HH 

PROVIDER: S-EPMC6004237 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature