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Influence of white matter fiber orientation on R2* revealed by MRI segmentation

Authors


Abstract

Purpose:

To investigate white matter heterogeneity using a multichannel segmentation of a large sample of structural and diffusion magnetic resonance imaging (MRI) data.

Materials and Methods:

A sample of 50 subjects was segmented using channels comprising exclusively structural (longitudinal and transverse relaxation times T1 and T2 and transverse relaxation rate R2*) and diffusion-based MRI indices (mean diffusivity and fractional anisotropy). These data were analyzed using a data driven approach in which no prior information was used.

Results:

The analysis revealed the splitting of white matter into two subclasses in which the longitudinal fasciculi were distinguished from inferior/superior ones. The distribution of the adopted indices in the obtained clusters showed that R2* was mainly responsible for this splitting.

Conclusion:

This result supports the observation, previously hypothesized in the literature, that R2* is influenced by the fiber orientation. J. Magn. Reson. Imaging 2013;37:85–91. © 2012 Wiley Periodicals, Inc.

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