High angular resolution diffusion imaging reveals intravoxel white matter fiber heterogeneity

DS Tuch, TG Reese, MR Wiegell… - … in Medicine: An …, 2002 - Wiley Online Library
DS Tuch, TG Reese, MR Wiegell, N Makris, JW Belliveau, VJ Wedeen
Magnetic Resonance in Medicine: An Official Journal of the …, 2002Wiley Online Library
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 …
Abstract
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.
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