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High angular resolution diffusion imaging reveals intravoxel white matter fiber heterogeneity
Author(s) -
Tuch David S.,
Reese Timothy G.,
Wiegell Mette R.,
Makris Nikos,
Belliveau John W.,
Wedeen Van J.
Publication year - 2002
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.10268
Subject(s) - diffusion mri , fiber , voxel , diffusion , white matter , nuclear magnetic resonance , orientation (vector space) , physics , tensor (intrinsic definition) , magnetic resonance imaging , chemistry , mathematics , geometry , computer science , artificial intelligence , radiology , medicine , organic chemistry , thermodynamics
Magnetic resonance (MR) diffusion tensor imaging (DTI) can resolve the white matter fiber orientation within a voxel provided that the fibers are strongly aligned. However, a given voxel may contain a distribution of fiber orientations due to, for example, intravoxel fiber crossing. The present study sought to test whether a geodesic, high b‐ value diffusion gradient sampling scheme could resolve multiple fiber orientations within a single voxel. In regions of fiber crossing the diffusion signal exhibited multiple local maxima/minima as a function of diffusion gradient orientation, indicating the presence of multiple intravoxel fiber orientations. The multimodality of the observed diffusion signal precluded the standard tensor reconstruction, so instead the diffusion signal was modeled as arising from a discrete mixture of Gaussian diffusion processes in slow exchange, and the underlying mixture of tensors was solved for using a gradient descent scheme. The multitensor reconstruction resolved multiple intravoxel fiber populations corresponding to known fiber anatomy. Magn Reson Med 48:577–582, 2002. © 2002 Wiley‐Liss, Inc.