Reversible alterations in brain metabolites during therapy for disseminated nocardiosis using proton magnetic resonance spectroscopy

We report reversible abnormalities in magnetic resonance spectra acquired f rom a patient with AIDS undergoing antibiotic and corticosteroid therapy fo r disseminated nocardiosis, a rare opportunistic infection of immunosuppres sed patients which can cause cerebral abscess formation. There was no clini cal, CT or MRI evidence of HIV-1 encephalitis. MR spectra were acquired bef ore and after treatment using a two-dimensional chemical shift imaging tech nique(TR 1500ms, TE 130ms). Prior to treatment, a rise in the choline to cr eatine ratio and a reduction in the N-acetylaspartate to creatine ratio wer e observed in MR spectra localized to areas of the left anteromedial centru m semiovale that appeared normal on MR imaging, After 16 weeks, the patient had recovered with complete resolution of the cerebral abscesses on MRI. T he MR spectral abnormalities also returned to normal. Two months later, the patient had a relapse with focal neurological signs and further abscesses were demonstrated on MRI of the brain. The patient subsequently died and hi stopathological and microbiological findings at autopsy confirmed the clini cal picture of a recurrence of cerebral nocardiosis with no evidence of HIV -1 encephalitis. This case illustrates reversible MR-measurable metabolite changes in the brain of an HIV-seropositive patient without HIV-1 encephali tis who underwent treatment for cerebral nocardiosis.