Clinicopathologic correlations of cranial magnetic resonance imaging of periventricular white matter.

We studied clinical, imaging, and autopsy data on 7 patients who underwent magnetic resonance imaging (MRI) during life. Small periventricular zones of increased T2 signal corresponded to a periventricular cap consisting of subependymal glial accumulations, with some loss of the ependymal lining, and a surrounding pale-staining area of finely textured myelin and axons with an altered glial pattern. The fine-fiber zone is identifiable anatomically as the subcallosal fasciculus. This histologic pattern of subependymal glial accumulations and fine fibers is normal and is often associated with fibrotic small blood vessels. More extensive subcortical MRI changes corresponded, in 1 case, to multiple sclerosis, and in another to subcortical arteriosclerotic encephalopathy (Binswanger's disease) with widespread fiber loss and lacunar changes. Wallerian degeneration secondary to infarction occurred in some areas of MRI abnormality.