1H spectroscopy in patients with amyotrophic lateral sclerosis

The authors investigate changes in brain metabolites among patients with amyotrophic lateral sclerosis (ALS). Twelve patients diagnosed with definite ALS (and 2 subgroups with either pronounced upper motoneuron signs or less obvious, probable upper motoneuron involvement) and 10 controls were examined. 1H studies were performed on a 1.5-T Siemens Magnetom Vision with single voxel (SV). A voxel (TR = 1500 ms, TE = 270 ms, 512 acquisitions, VOI = 8 cm3) was placed bilaterally in the precentral gyrus. In addition, chemical shift imaging (CSI) (VOI = 1 x 1 x 1.5 cm, TR = 1500 ms, TE = 135 ms) was performed. Ratios of peak integrals (N-acetyl-aspartate/choline, N-acetyl-aspartate/creatine, and creatine/choline) were determined. A Mann-Whitney U Test and a Wilcoxon Matched Pairs Test were applied.

The statistical analysis failed to demonstrate any significant differences between the ALS patients and the controls with respect to ratio measures. Using CSI, it was found that patients with clinically pronounced upper motoneuron signs had significantly lower (P = .037) N-acetyl-aspartate/choline ratios in the more affected hemisphere.

The authors conclude that CSI is more effective at detecting lower N-acetyl-aspartate/choline levels among ALS patients than is SV.