Proton spectroscopy in HIV infection: Relaxation times of cerebral metabolites

In vivo proton spectroscopy has demonstrated abnormalities in the cerebral metabolite ratios from subjects with acquired immunodeficiency syndrome (AIDS). Some of the sequences employed are subject to T 1 or T 2 weighting, which may affect spectroscopic interpretation. The relaxation times of choline (Cho), creatine (Cr), and N-acetyl (NA) resonances have been estimated at 1.5 T in 21 patients infected with the human immunodeficiency virus (HIV) and 8 controls using gradient localised, spin-echo spectroscopic sequences of varying echo and repetition times. A statistically significant increase in the T 2 of NA was found in the HIV seropositive patients who had diffuse abnormalities on MR imaging consistent with HIV encephalopathy (493±199 ms) when compared to controls (292±118 ms; p