Abnormalities of the brain in AIDS patients: correlation of postmortem MR findings with neuropathology

The ability of MR to detect CNS lesions in AIDS patients was evaluated by postmortem scanning of 10 formalin-fixed brains. Nine patients had premortem mental status changes and five had focal neurologic deficits. The brains were imaged and sectioned in corresponding planes. MR images showed atrophy in eight of the 10. All grossly identified lesions and areas of MR abnormality were histologically evaluated. Areas of infarction and necrosis associated with cytomegalovirus (CMV) or Toxoplasma gondii were seen as foci of increased signal intensity. Severe ventriculitis and focal gliosis were also visible by MR. Neither CT nor MR was able to detect diffuse CMV- or HIV-associated microglial nodules. Dementia without focal neurologic signs correlated best with the presence of diffuse microglial nodules at pathology. Our results demonstrate the usefulness of correlating postmortem MR imaging with neuropathology, and the relevance of postmortem findings to the interpretation of MR images in living patients.