White matter lesions of the aging brain: Pathologic correlation with MR imaging

The brains from consecutive autopsies in individuals over the age of 50 who died of nonneurologic causes were studied with postmortem in vitro MR imaging. Seven of the 19 postmortem MR images demonstrated subcortical periventricular white matter hyperintensities on the T2-weighted spin-echo images. Histologic examination of these lesions revealed a spectrum of changes ranging from moderate arteriosclerosis to severe vascular disease, accompanied by white matter abnormalities including pallor, gliosis, cystic rarefaction, and necrosis. The severity of the changes increased with cerebral vascular risk factors. Although the presence of white matter pathology increased with age, it was not a universal phenomenon of normal aging as our oldest patient (aged 89) had no lesions. While the most severe pathologic changes were consistent with those of subcortical arteriosclerotic encephalopathy (SAE) or Binswanger disease, none of the cases was given this antemortem clinical diagnosis. It is postulated that the extreme sensitivity of MR imaging to altered tissue water content may allow the radiologist to identify a prolonged preclinical stage of this uncommon clinical diagnosis