BACKGROUND - HIV dementia is a form of subcortical dementia. Clinical, radiologic, pathologic, and biochemical studies suggest a major contribution of basal ganglia dysfunction to the pathogenesis of this disorder. Many investigators have proposed a contribution of a disrupted blood-brain barrier (BBB) to the pathogenesis of HIV dementia.
OBJECTIVE - To identify microvascular abnormalities in vivo in basal ganglia or white matter of persons with HIV dementia.
METHODS - Time course of MRI postcontrast enhancement was determined in basal ganglia and white matter of HIV-infected persons without dementia (Memorial Sloan Kettering [MSK] score of 0; n = 4); HIV-infected persons with mild dementia (MSK score of 0.5; n = 2); and HIV-infected persons with moderate-to-severe dementia (MSK > or = 1.0; n = 6).
RESULTS - Increased basal ganglia enhancement was observed in individuals with moderate-to-severe dementia relative to nondemented individuals, both immediately and 30 minutes after contrast administration. Decline of basal ganglia enhancement was slower in the moderately to severely demented patients and, when normalized to intravascular enhancement of sagittal sinus, suggested leakage of contrast agent, consistent with increased permeability of BBB. A significant correlation between the postcontrast fractional enhancement at 30 minutes (FE30) and the MSK score was noted. White matter showed no significant differences in postcontrast enhancement among the three groups.
CONCLUSION - Increased early enhancement in basal ganglia of the HIV dementia group is consistent with increased regional cerebral blood volume (rCBV). Increased late enhancement is strongly suggestive of BBB disruption. Similar abnormalities were absent in the white matter adjacent to the caudate nucleus.