Cerebral MR spectroscopy in neurologically asymptomatic HIV-infected patients

Purpose: To detect early metabolic changes in the brain of neurologically asymptomatic HIV-infected patients with normal MR imaging and to find the correlation between 1H MR results and immune status. Material and Methods: Twenty neurologically asymptomatic HIV seropositive patients underwent MR imaging and single-voxel 1H MR spectroscopy (MRS) using a PRESS sequence. For all patients, the signals from N-acetyl-aspartate (NAA), choline-containing compounds (Cho), creatine-phosphocreatine (Cr) and myoinositol (mI) were compared with 32 healthy volunteers as metabolite ratios and metabolite areas to non-suppressed water area ratios. Results: In HIV patients, the NAA/Cho ratio was significantly lower (p < 0.01), but there were no changes in NAA/Cr ratio. A statistically significant reduction in NAA/H-2 O and Cr/H-2 O (both p < 0.05) was observed. For the immune status there was a statistically significant correlation (r= 0.47, p < 0.05) between CD4 counts and NAA/H-2 O ratio. A significant increase in Cho/Cr (p < 0.001) and mI/Cr (p < 0.01) ratios in HIV patients was found, but Cho/H-2 O and mI/H-2 O concentrations were non-significantly increased. Conclusion: These results indicate that neuronal loss and gliosis in HIV-infected patients may be associated with impairment of energy metabolism. The spectral changes found suggest that 1H MRS can be used for early detection of brain damage induced by HIV.