title: Selective reduction of N-acetylaspartate in medial temporal and parietal lobes in AD.
abstract: BACKGROUND
  Both AD and normal aging cause brain atrophy, limiting the ability of MRI to distinguish between AD and age-related brain tissue loss. MRS imaging (MRSI) measures the neuronal marker N-acetylaspartate (NAA), which could help assess brain change in AD and aging.
  
  
  OBJECTIVE
  To determine the effects of AD on concentrations of NAA, and choline- and creatine-containing compounds in different brain regions and to assess the extent NAA in combination with volume measurements by MRI improves discrimination between AD patients and cognitively normal subjects.
  
  
  METHODS
  Fifty-six patients with AD (mean age: 75.6 +/- 8.0 years) and 54 cognitively normal subjects (mean age: 74.3 +/- 8.1 years) were studied using MRSI and MRI.
  
  
  RESULTS
  NAA concentration was less in patients with AD compared with healthy subjects by 21% (p < 0.0001) in the medial temporal lobe and by 13% to 18% (p < 0.003) in parietal lobe gray matter (GM), but was not changed significantly in white matter and frontal lobe GM. In addition to lower NAA, AD patients had 29% smaller hippocampi and 11% less cortical GM than healthy subjects. Classification of AD and healthy subjects increased significantly from 89% accuracy using hippocampal volume alone to 95% accuracy using hippocampal volume and NAA together.
  
  
  CONCLUSIONS
  In addition to brain atrophy, NAA reductions occur in regions that are predominantly impacted by AD pathology.
authors.affiliation: Magnetic Resonance Unit, DVA Medical Center San Francisco, CA 94121, USA. nschuff@itsa.ucsf.edu
authors.forename: N
authors.initials: N
authors.lastname: Schuff
authors.forename: A A
authors.initials: AA
authors.lastname: Capizzano
authors.forename: A T
authors.initials: AT
authors.lastname: Du
authors.forename: D L
authors.initials: DL
authors.lastname: Amend
authors.forename: J
authors.initials: J
authors.lastname: O'Neill
authors.forename: D
authors.initials: D
authors.lastname: Norman
authors.forename: J
authors.initials: J
authors.lastname: Kramer
authors.forename: W
authors.initials: W
authors.lastname: Jagust
authors.forename: B
authors.initials: B
authors.lastname: Miller
authors.forename: O M
authors.initials: OM
authors.lastname: Wolkowitz
authors.forename: K
authors.initials: K
authors.lastname: Yaffe
authors.forename: M W
authors.initials: MW
authors.lastname: Weiner
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000378:metabolism* / Q000473:pathology; D000704:Analysis of Variance; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism*; D001284:Atrophy; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D010296:Parietal Lobe / Q000378:metabolism* / Q000473:pathology; D013702:Temporal Lobe / Q000378:metabolism* / Q000473:pathology
chemical_list: D001224:Aspartic Acid; C000179:N-acetylaspartate