In vivo localized NMR proton spectroscopy of normal appearing white matter in patients with multiple sclerosis.

We used a rapid long TE proton magnetic resonance spectroscopic (MRS) sequence in the normal appearing white matter of 11 patients with definite multiple sclerosis (MS) localizing the volume of interest in the centrum semi-ovale. The metabolic changes were compared to the same area in 11 normal brains. We found a significant decrease in NAA/Cr ratios and a borderline significance of increase in Cho/Cr ratios in patients with MS. A discriminant analysis was performed on these data. This allowed to obtain a simple ratio, NAA/(Cho+Myo), which discriminated MS patients from controls. Our results indicate that normal appearing white matter on MRI is biochemically abnormal in patients with MS. In addition MRS could be routinely used after a standard MRI examination in patients with MS for clinical correlations, total load of the disease assessment and monitoring clinical trials.