Proton MRS of large multiple sclerosis lesions reveals subtle changes in metabolite T1 and area

The T-1 values of metabolites were measured in eight subjects with clinically definite multiple sclerosis (MS) having at least one large brain lesion (2 6 +/- 0 7 ml) and in eight age- and sex-matched healthy controls MRS examinations were conducted at 1 5 T using point resolved spectroscopy (PRESS) (TE = 30 ms, TR = 530, 750, 1200, 1500, 3500, 5000 ms) Spectra were acquired from a voxel placed in the largest lesion in the subject with MS, and in a corresponding voxel (same size and region) in normal white matter (NWM) in the matched control, and were fitted using LCModel As there are regional variations in metabolite and water T-1 and metabolite signal areas, careful placement of the control voxel was necessary to measure subtle differences between the lesions and NWM The T-1 and T-1 corrected signal areas of creatine were the same in MS lesions as in controls The T-1 values of choline were significantly shorter in MS lesions located in occipital and parietal, but not in frontal, white matter N Acetylaspartate (NAA) and myoinositol T-1 values in MS lesions were similar to those in NWM, however, the area of myoinositol correlated directly with lesion water T-1, and the area of NAA correlated inversely with lesion water T-1 MR spectra acquired at short TR require T-1 correction of choline for accurate quantification Careful voxel placement in controls to match lesion location in subjects with MS enables a clearer view of the subtle changes in lesions Copyright (C) 2010 John Wiley & Sons, Ltd