Reproducibility of proton MR spectroscopic imaging findings.

PURPOSE To study the intraindividual, interindividual, and intraregional reproducibility of multisection proton MR spectroscopic imaging in healthy adults.

METHODS Six subjects were studied three times with proton MR spectroscopic imaging. Multisection long-echo-time proton MR spectroscopic imaging permits simultaneous acquisition of N-acetylaspartate (NAA), choline-containing compounds (Cho), and creatine plus phosphocreatine (Cr) signal intensities from four 15-mm-thick sections divided into 0.84-mL single-volume elements. Regions of interest were the frontal cortex, the occipital cortex, the parietal cortex, the insular cortex, the cingulate gyrus, the centrum semiovale, the thalamus, and the caudate. Statistical evaluation was performed by analyses of variance and components of variance method.

RESULTS The ratio NAA/Cr showed the lowest overall coefficient of variation (CV, %) in most of the regions of interest (range, 8.9 to 26.1). Interregional differences in the overall CV were present. Interindividual CVs ranged from 4.2 to 8.7 for NAA/Cr, from 6.8 to 17.4 for NAA/Cho, and from 5.0 to 13.6 for Cho/Cr. Intraindividual CVs ranged from 8.2 to 22.2 for NAA/Cr, from 12.8 to 25.8 for NAA/Cho, and from 4.5 to 21.0 for Cho/Cr. Intraregional CVs ranged from 12.3 to 21.2 for NAA/Cr, from 13.0 to 20.4 for NAA/Cho, and from 12.2 to 18.9 for Cho/Cr.

CONCLUSIONS Proton MR spectroscopic imaging showed good overall reproducibility. The finding of interregional variations of CV indicates that care is needed when using this imaging technique for follow-up studies.