A 35-year-old Hispanic man presented to the emergency room with flulike symptoms and totalbody pain. Nine years earlier, he was diagnosed with human immunodeficiency virus (HIV) infection. Although he had been undergoing highly active antiretroviral therapy (HAART), he had been noncompliant for the past year. He had been hospitalized several times for various infections, including shigellosis and syphilis, and had tested positive for Toxoplasma gondii antibodies.Shortly after admission to the hospital, the patient began to experience bilateral frontal headaches. He was febrile to 101.9°F, but otherwise his other vital signs were stable. Physical examination revealed a sluggish but reactive right pupil. No other neurologic deficits were found. Laboratory test results revealed an eosinophil count of 0.24 (normal range, 0-0.08) and a CD4 count of 4 (normal range, 500-1400). A lumbar puncture was performed, and a nonelevated opening pressure was obtained. The cerebrospinal fluid leukocyte count was mildly increased, at 32 (normal range, 0-5). Subsequent blood and cerebrospinal fluid cultures were negative, and results of serologic testing for herpes simplex virus, Cryptococcus, and Strongyloides also were negative. Computed tomographic (CT) and magnetic resonance (MR) imaging of the brain were ordered to further evaluate the patient's condition.
Imaging FindingsInitial unenhanced CT of the brain revealed multiple discrete low-attenuation parenchymal lesions in the right basal ganglia, the right internal capsule, the right hippocampus, the right and left thalami, and the left caudate body (Fig 1).MR imaging of the brain revealed a widespread distribution of hyperintense lesions on both fluid-attenuated inversion recovery (FLAIR) (Fig 2a) and T2-weighted images (Fig 2b). The lesions were situated primarily at the gray matter-white matter interfaces and in the basal ganglia. On T1-weighted images, many of the larger lesions demonstrated increased signal intensity at the peripheries (Fig 2c). In our case, signal intensity was increased to a greater degree than usual, a finding that may indicate a larger amount of subacute mural hemorrhage or Abbreviations: AIDS = acquired immunodeficiency syndrome, CNS = central nervous system, FLAIR = fluid-attenuated inversion recovery, HAART = highly active antiretroviral therapy, HIV = human immunodeficiency virus RadioGraphics 2009; 29:1200-1205 • Published online 10.1148/rg.294085205 • Content Code: Figure 1. Unenhanced CT scan of the brain shows discrete low-attenuation lesions in the basal ganglia (arrow) and hippocampus (arrowhead).