HIGH-SIGNAL LESIONS IN THE MIDBRAIN ON T1-WEIGHTED MRI IN AN HIV-INFECTED PATIENT

In addition to opportunistic infections, neoplasms or cerebrovascular complications, metabolic encephalopathies are a classical cause of dif fuse brain dysfunction in HIV infection and are frequent in the termin al stage. We report an HIV-infected patient with symmetrical, focally increased signal in the midbrain on proton density- and T1-weighted MR I without corresponding high signal on T2-weighted images or on CT. Wh ile the precise nature and cause of this uncommon finding is not fully understood, the available evidence suggests that these lesions might represent a novel metabolic encephalopathy.