MR imaging and CT of central nervous system tuberculosis in the patient with AIDS.

CNS TB represents a disease that complicates AIDS with an increasing incidence in endemic areas as well as in developed countries in those patients who have some risk factors such as intravenous drug abuse. Although TB infection of the CNS in AIDS patients may follow a rapidly progressive course, the imaging findings otherwise are similar to those of the nonimmunosuppressed population. Meningeal enhancement, hydrocephalus, parenchymal granulomata, and infarcts are seen frequently and are often observed in combination with one another. Nevertheless, the differential diagnosis in AIDS patients must include other opportunistic infections and primary or metastatic lymphoma of the CNS. Spinal TB usually is seen in the form of epidural abscess secondary to tuberculous spondylitis, although it may be seen in isolation of spinal column involvement. The differential diagnosis includes spinal lymphoma or pyogenic abscess formation. Radiculomyelitis or isolated spinal cord tuberculomata are much less frequently observed and can be suspected on imaging only if there is concomitant evidence of the classic findings of intracranial TB.