title: Quantitative proton magnetic resonance spectroscopy of the subcortical white matter in motor neuron disease.
abstract: 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 MND patients, attributed to neuronal loss or dysfunction leading to a reduction in NAA. We have expanded this analysis to evaluate absolute concentrations of NAA, (Cr + PCr) and choline-containing compounds (Cho) in the subcortical white matter in the motor region in 16 MND patients (8 with bulbar onset and 8 with limb onset) and 8 healthy, age-matched controls.
  
  
  METHODS
  Single voxel 1H-MRS was performed using a PRESS localization sequence. Metabolite concentrations were determined using the water signal as an internal standard.
  
  
  RESULTS
  We found no differences in the concentrations of NAA ([NAA]), (Cr + PCr) ([Cr + PCr]) or Cho ([Cho]) in the motor region on comparing the total MND group and controls (P > 0.3). No difference was found in [NAA] in the bulbar-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 pathological process in MND, and this should be considered in the interpretation of metabolite peak area ratios. The elevated (Cr + PCr) may represent gliosis in the subcortical white matter in the motor cortex region.
authors.affiliation: Department of Clinical Neurosciences, Institute of Psychiatry and Guy's, King's & St Thomas' School of Medicine, London, UK.
authors.forename: C M
authors.initials: CM
authors.lastname: Ellis
authors.forename: A
authors.initials: A
authors.lastname: Simmons
authors.forename: A
authors.initials: A
authors.lastname: Glover
authors.forename: J M
authors.initials: JM
authors.lastname: Dawson
authors.forename: S C
authors.initials: SC
authors.lastname: Williams
authors.forename: P N
authors.initials: PN
authors.lastname: Leigh
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology*; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D016472:Motor Neuron Disease / Q000473:pathology*; D009412:Nerve Fibers / Q000473:pathology*; D011522:Protons
chemical_list: D011522:Protons