In a multisite study of brain MR spectroscopy performed at 26 sites, interindividual differences were found as the main contributor to variability, demonstrating that appropriately analyzed MR spec... Background The hardware and software differences between MR vendors and individual sites influence the quantification of MR spectroscopy data. An analysis of a large data set may help to better und...

Motion has an adverse effect on spectral quality and needs to be properly identified in MR spectroscopy (MRS) scans. Spectral subtraction‐based techniques like J‐difference editing are prone to be affected more by subject motion where motion can result in false peaks or inefficient subtraction of peaks. Introducing a water signal‐based interleaved navigator scan in the MEGA point‐resolved spectroscopy (MEGA‐PRESS) sequence and acquiring data on a shot‐by‐shot basis, subject motion inside a scanner was tracked and motion‐corrupted data were identified and excluded from the dataset. Performing a γ‐aminobutyric acid (GABA) editing scan at the occipital cortex, it was possible to retrieve a properly edited GABA spectrum from a dataset otherwise to be discarded due to motion. This study demonstrates the importance of independent motion assessment in J‐difference editing. Magn Reson Med 58:808–812, 2007.

BACKGROUND AND PURPOSE: Abnormalities in GABA concentration [GABA] have been associated with several neuropsychiatric disorders, and research has suggested that GABA may play a role in sensorimotor cortex function. We sought to determine whether identifying a change in [GABA] within the sensorimotor cortex of patients with MS has any effect on motor function and would provide information about the adaptive/compensatory mechanisms involved in the attempt to maintain motor function during disease progression. MATERIALS AND METHODS: In 19 healthy controls and 30 patients with MS, we assessed task performance with the MS Functional Composite scale and its components (T25FW test, 9HPT, and PASAT). With in vivo MR spectroscopy, we measured [GABA] in the sensorimotor cortex and determined correlations between [GABA] and task performance. We also assessed the association between [GABA] and cortical activation volume after a bilateral finger-tapping task. RESULTS: [GABA] was inversely correlated with 9HPT scores in patients with MS, indicating a worsening of performance with increased [GABA]. No significant correlation was observed between [GABA] and T25FW or PASAT scores. [GABA] was directly correlated with primary motor cortex activation volume after the finger-tapping task in patients with MS. CONCLUSIONS: These results suggest that cortical [GABA] may be a marker of function and reorganization/adaptation of cortical gray matter in MS.