Proton magnetic resonance spectroscopy of human basal ganglia: response to cocaine administration

Background: Proton magnetic resonance spectroscopy was used to determine the effects of intravenous cocaine or placebo administration on human basal ganglia water and metabolite resonances. Methods: Long echo time, proton magnetic resonance spectra of water and intracellular metabolites were continuously acquired from an 8-cm3 voxel centered on the left caudate and putamen nuclei before, during, and after the intravenous administration of cocaine or a placebo in a double-blind manner. Results: Cocaine, at both 0.2 and 0.4 mg/kg, did not alter the peak area for water. Cocaine at 0.2 mg/kg induced small and reversible increases in choline-containing compounds and N-acetylaspartate peak areas. Cocaine at 0.4 mg/kg induced larger and more sustained increases in choline-containing compounds and N-acetylaspartate peak areas. No changes in either water or metabolite resonances were noted following placebo administration. Conclusions: These increases in choline-containing compounds and N-acetylaspartate peak areas may reflect increases in metabolite T2 relaxation times secondary to osmotic stress and/or increased phospholipid signaling within the basal ganglia following cocaine administration. This is the first report of acute, drug-induced changes in the intensity of human brain proton magnetic resonance spectroscopy resonance areas.