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Title
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In vivo observation and biophysical interpretation of time-dependent diffusion in human white matter
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Author
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Abstract
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| 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. |
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Language
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English
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Source (journal)
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Neuroimage. - New York
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Publication
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New York
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2016
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ISSN
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1053-8119
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DOI
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10.1016/J.NEUROIMAGE.2016.01.018
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Volume/pages
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129
(2016)
, p. 414-427
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ISI
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000372745300035
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Pubmed ID
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26804782
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Full text (Publisher's DOI)
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Full text (open access)
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Full text (publisher's version - intranet only)
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