Tensor diffusion imaging in B12 leukoencephalopathy.

Anisotropy measurements were obtained from periventricular foci of T2 prolongation and adjacent normal-appearing white matter in a case of B12 leukoencephalopathy. Measurements were compared with mean values from two age-matched control subjects. Anisotropy was greatly reduced in the lesions evident on T2-weighted images and in the normal-appearing adjacent white matter (WM), indicating that the extent of WM tract disruption was greater than could be identified on routine MR sequences.