Axial diffusivity (AD) vs. Radial diffusivity (RD) in GM ROIs with abnormally high FA.

<p>There are two patterns that can explain the increased FA evinced in GM of PPCS patients. In Cluster 1 (red) AD is abnormally high and RD is normal, consistent with an animal model of gliosis. In Cluster 2 (blue) both AD and RD are abnormally low, a pattern that was not reported in previous GM studies and which remains to be explained.