Increased cerebral blood volume in HIV-positive patients detected by functional MRI

Objective: To study changes in cerebral hemodynamics related to HIV infection. Background: Cerebral injury is a well-known manifestation of HIV infection. Physiologic changes in the HIV brain may precede structural changes and may be detected by functional MRI (fMRI). Methods: Dynamic contrast fMRI was used to measure the cerebral blood volume (CBV) in 13 patients infected with HIV and in 7 healthy control subjects. Results: Significant increases in dynamic CBV were found in the deep (p < 0.001) and cortical gray matter (p < 0.05) of HIV-positive (HIV+) patients. Patients with definite cognitive impairment showed significantly greater increases in CBV in the deep gray matter (DGM) compared with those without impairment. In one patient with rapidly progressive cognitive impairment, these abnormalities reversed and paralleled clinical improvement after initiation of zidovudine monotherapy. Conclusions: This study supports the hypothesis that HIV infection is associated with significant cerebral hemodynamic changes, particularly in the DGM, that may contribute to cognitive dysfunction in AIDS. Functional MRI may be useful for early detection of cerebral injury and for the assessment of novel therapies.