Quantitative proton magnetic resonance spectroscopy of the subcortical white matter in motor neuron disease

BACKGROUND: Using proton magnetic resonance spectroscopy, the authors have previously demonstrated a reduction in the N-acetyl aspartate/creatine and phosphocreatine) (NAA/(Cr+PCr)) ratio in the motor region in bulbar-onset M ND patients, attributed to neuronal loss or dysfunction leading to a reduct ion in NAA, We have expanded this analysis to evaluate absolute concentrati ons of NAA, (Cr+PCr) and choline-containing compounds (Cho) in the subcorti cal white matter in the motor region in 16 MND patients (8 with bulbar onse t and 8 with limb onset) and 8 healthy, age-matched controls. METHODS: Single voxel H-1-MRS was performed using a PRESS localization sequ ence. Metabolite concentrations were determined using the water signal as a n internal standard. RESULTS: We found no differences in the concentrations of NAA ([NAA]), (CrPCr) ([Cr+PCr]) or Cho ([Cho]) in the motor region on comparing the total M ND group and controls (P > 0.3). No difference was found in [NAA] in the bu lbar-onset group compared with the limb-onset group (P = 0.70), but [Cr+PCr ] was significantly higher in the bulbar-onset group (P = 0.04). CONCLUSIONS: Our results suggest that [Cr+PCr] may be affected by the patho logical process in MND, and this should be considered in the interpretation of metabolite peak area ratios. The elevated (Cr+PCr) may represent gliosi s in the subcortical white matter in the motor cortex region.