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Neuroimage. 2018 Nov 15;182:360-369. doi: 10.1016/j.neuroimage.2017.09.030. Epub 2017 Sep 19.

TE dependent Diffusion Imaging (TEdDI) distinguishes between compartmental T2 relaxation times.

Author information

1
Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, NY, USA. Electronic address: Jelle.Veraart@nyumc.org.
2
Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, NY, USA.

Abstract

Biophysical modeling of macroscopic diffusion-weighted MRI signal in terms of microscopic cellular parameters holds the promise of quantifying the integrity of white matter. Unfortunately, even fairly simple multi-compartment models of proton diffusion in the white matter do not provide a unique, biophysically plausible solution. Here we report a nontrivial diffusion MRI signal dependence on echo time (TE) in human white matter in vivo. We demonstrate that such TE dependence originates from compartment-specific T2 values and that it is a promising "orthogonal measure" able to break the degeneracy in parameter estimation, and to yield important relaxation metrics robustly. We thereby enable the precise estimation of the intra- and extra-axonal water T2 relaxation times, which is precluded by a limited signal-to-noise ratio when using multi-echo relaxometry alone.

KEYWORDS:

Diffusion; MRI; Modeling; Transverse relaxation

PMID:
28935239
PMCID:
PMC5858973
[Available on 2019-11-15]
DOI:
10.1016/j.neuroimage.2017.09.030

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