title: Regional gray and white matter metabolite differences in subjects with AD, with subcortical ischemic vascular dementia, and elderly controls with 1H magnetic resonance spectroscopic imaging.
abstract: OBJECTIVE
  To use 1H magnetic resonance spectroscopic imaging to study differences in neuron density (N-acetylaspartate [NAA]), membrane phospholipid metabolites (choline [Cho]), and creatine-containing metabolites (creatine plus phosphocreatine [Cr]) in subjects with Alzheimer's disease (AD), with subcortical ischemic vascular dementia (SIVD), and elderly controls.
  
  
  METHODS
  Cross-sectional, between groups.
  
  
  METHODS
  A Veterans Affairs medical center and university memory clinic.
  
  
  METHODS
  Forty elderly subjects with AD (n = 14), with SIVD (n = 8), and elderly controls (n = 18).
  
  
  METHODS
  We used 1H magnetic resonance spectroscopic imaging to acquire spectra from a 80 x 100 x 17-mm volume superior to the lateral ventricles. Spectra were analyzed from voxels in anterior, medial, and posterior gray and white matter using nuclear magnetic resonance-1 and the results were compared between groups using repeated measures analysis of variance (ANOVA), Tukey's test, and individual Student's t tests.
  
  
  RESULTS
  Using ANOVA, significantly lower levels of NAA/Cho and NAA/Cr and significantly higher levels of Cho/Cr were observed across both gray and white matter voxels in subjects with AD. Using individual Student's t tests, a significantly lower level of NAA/Cho and a higher level of Cho/Cr were observed in the posterior gray matter in subjects with AD. Using ANOVA in subjects with SIVD, significantly lower gray and white matter NAA/Cr levels were observed. Using Tukey's test, the NAA/Cr level was significantly lower in frontal white matter voxels in subjects with SIVD compared with controls.
  
  
  CONCLUSIONS
  Our findings in subjects with AD suggest neuron loss in gray matter, axon loss in white matter, and altered Cho metabolism in posterior brain regions. Our findings in subjects with SIVD are consistent with higher levels of creatine-containing metabolites and/or lower levels of NAA in frontal white matter.
authors.affiliation: Magnetic Resonance Spectroscopy Unit, Department of Veterans Affairs Medical Center, San Francisco, USA.
authors.forename: S
authors.initials: S
authors.lastname: MacKay
authors.forename: D J
authors.initials: DJ
authors.lastname: Meyerhoff
authors.forename: J M
authors.initials: JM
authors.lastname: Constans
authors.forename: D
authors.initials: D
authors.lastname: Norman
authors.forename: G
authors.initials: G
authors.lastname: Fein
authors.forename: M W
authors.initials: MW
authors.lastname: Weiner
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000378:metabolism*; D000704:Analysis of Variance; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D002545:Brain Ischemia / Q000150:complications*; D002540:Cerebral Cortex / Q000098:blood supply*; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D003430:Cross-Sectional Studies; D015140:Dementia, Vascular / Q000209:etiology / Q000378:metabolism*; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009417:Nerve Tissue / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism; D011522:Protons
chemical_list: D011522:Protons; D010725:Phosphocreatine; D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline