A closed-form method for improving inter-subject coherence in diffusion tensor magnetic resonance imaging

A simple method is presented to reduce within-group inter-subject scatter in diffusion tensor magnetic resonance imaging (DT-MRI). By "borrowing strength" across co-registered subjects to accommodate indirect effects of unmeasured machine and physiological noise, the method reduces voxel-specific tensor variance across subjects. The technique may aid in fiber bundle atlas construction, in testing differences between groups of subjects, and in automated outlier detection. While the technique does not in itself address DT-MRI signal artifact issues directly, it may serve to lessen the effects of these artifacts when their sources have not been measured. An example application to DT-MRI of twelve healthy male volunteers at the splenium of the corpus callosum slightly right of midline demonstrates the possible utility of the method.