| Title |
|
|
|
In vivo observation and biophysical interpretation of time-dependent diffusion in human white matter
| |
| Author |
|
|
|
| |
| Abstract |
|
|
|
| The presence ofmicrometer-level restrictions leads to a decrease of diffusion coefficient with diffusion time. Here we investigate this effect in human white matter in vivo. We focus on a broad range of diffusion times, up to 600 ms, covering diffusion length scales up to about 30 mu m. We perform stimulated echo diffusion tensor imaging on 5 healthy volunteers and observe a relatively weak time-dependence in diffusion transverse to major fiber tracts. Remarkably, we also find notable time-dependence in the longitudinal direction. Comparing models of diffusion in ordered, confined and disordered media, we argue that the time-dependence in both directions can arise due to structural disorder, such as axonal beads in the longitudinal direction, and the random packing geometry of fibers within a bundle in the transverse direction. These time-dependent effects extend beyond a simple picture of Gaussian compartments, and may lead to novel markers that are specific to neuronal fiber geometry at the micrometer scale. (C) 2016 Elsevier Inc. All rights reserved. | | |
| Language |
|
|
|
English
| |
| Source (journal) |
|
|
|
Neuroimage. - New York | |
| Publication |
|
|
|
New York : 2016
| |
| ISSN |
|
|
|
1053-8119
| |
| Volume/pages |
|
|
|
129(2016), p. 414-427
| |
| ISI |
|
|
|
000372745300035
| |
| Full text (Publisher's DOI) |
|
|
| | |
| Full text (publisher's version - intranet only) |
|
|
| | |
|