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Revealing mesoscopic structural universality with diffusion

Author:
Novikov, Dmitry S., Jensen, Jens H., Helpern, Joseph A., Fieremans, Els
Source:
Proceedings of the National Academy of Sciences of the United States of America 2014 v.111 no.14 pp. 5088-5093
ISSN:
0027-8424
Subject:
brain, diffusivity, image analysis, models, muscles, porous media, stroke
Abstract:
Measuring molecular diffusion is widely used for characterizing materials and living organisms noninvasively. This characterization relies on relations between macroscopic diffusion metrics and structure at the mesoscopic scale commensurate with the diffusion length. Establishing such relations remains a fundamental challenge, hindering progress in materials science, porous media, and biomedical imaging. Here we show that the dynamical exponent in the time dependence of the diffusion coefficient distinguishes between the universality classes of the mesoscopic structural complexity. Our approach enables the interpretation of diffusion measurements by objectively selecting and modeling the most relevant structural features. As an example, the specific values of the dynamical exponent allow us to identify the relevant mesoscopic structure affecting MRI-measured water diffusion in muscles and in brain, and to elucidate the structural changes behind the decrease of diffusion coefficient in ischemic stroke.
Agid:
1785458