Quantitative 1H MRS of the human brain in vivo based on the stimulation phantom calibration strategy.

Normal metabolite concentrations were determined in five different brain regions of healthy adult volunteers using proton magnetic resonance spectroscopy (1H MRS) in vivo. The absolute in vivo concentrations of N-acetylaspartate (NAA), creatine and phosphocreatine (Cre), and choline containing compounds (Cho) were quantified from measurements obtained with a head-shaped simulation phantom. Scanner performance and calibration accuracy were assessed by phantom experiments. Localized spectra were acquired on clinical 1.5 T systems using the PRESS localization sequence with frequency selective water suppression. Comparison of the results obtained from phantom experiments and human brain in vivo strongly suggests that reproducibility in vivo mainly depends on the topologic metabolite heterogeneity of brain tissue in combination with relative volume dislocalization.