title: Early detection and longitudinal changes in amyotrophic lateral sclerosis by (1)H MRSI.
abstract: OBJECTIVE
  To determine 1) the reproducibility of metabolite measurements by (1)H MRS in the motor cortex; 2) the extent to which (1)H MRS imaging (MRSI) detects abnormal concentrations of N-acetylaspartate (NAA)-, choline (Cho)-, and creatine (Cre)-containing compounds in early stages of ALS; and 3) the metabolite changes over time in ALS.
  
  
  METHODS
  Sixteen patients with definite or probable ALS, 12 with possible or suspected ALS, and 12 healthy controls underwent structural MRI and multislice (1)H MRSI. (1)H MRSI data were coregistered with tissue-segmented MRI data to obtain concentrations of NAA, Cre, and Cho in the left and right motor cortex and in gray matter and white matter of nonmotor regions in the brain.
  
  
  RESULTS
  The interclass correlation coefficient of NAA was 0.53 in the motor cortex tissue and 0.83 in nonmotor cortex tissue. When cross-sectional data for patients were compared with those for controls, the NAA/(Cre + Cho) ratio in the motor cortex region was significantly reduced, primarily due to increases in Cre and Cho and a decrease in NAA concentrations. A similar, although not significant, trend of increased Cho and Cre and reduced NAA levels was also observed for patients with possible or suspected ALS. Furthermore, in longitudinal studies, decreases in NAA, Cre, and Cho concentrations were detected in motor cortex but not in nonmotor regions in ALS.
  
  
  CONCLUSIONS
  Metabolite changes measured by (1)H MRSI may provide a surrogate marker of ALS that can aid detection of early disease and monitor progression and treatment response.
authors.affiliation: Department of Radiology, University of California at San Francisco, USA.
authors.forename: J
authors.initials: J
authors.lastname: Suhy
authors.forename: R G
authors.initials: RG
authors.lastname: Miller
authors.forename: R
authors.initials: R
authors.lastname: Rule
authors.forename: N
authors.initials: N
authors.lastname: Schuff
authors.forename: J
authors.initials: J
authors.lastname: Licht
authors.forename: V
authors.initials: V
authors.lastname: Dronsky
authors.forename: D
authors.initials: D
authors.lastname: Gelinas
authors.forename: A A
authors.initials: AA
authors.lastname: Maudsley
authors.forename: M W
authors.initials: MW
authors.lastname: Weiner
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis* / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D018450:Disease Progression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000378:metabolism* / Q000473:pathology; D015203:Reproducibility of Results
chemical_list: D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline