title: A comparative study of the different N-acetylaspartate measures of the medial temporal lobe in Alzheimer's disease.
abstract: OBJECTIVE
  To investigate group differences and correlations and to determine the sensitivity and specificity of different measures of the neuronal marker N-acetylaspartate (NAA) in the medial temporal lobe of Alzheimer's Disease (AD) patients.
  
  
  METHODS
  The metabolic ratio NAA/creatine (Cr), the absolute concentration of NAA referenced against brain tissue (BT) water and NAA multiplied with the amount of BT in the proton magnetic resonance spectroscopy (1H-MRS) voxel were assessed in patients and healthy controls with a single-voxel 1H-MRS protocol.
  
  
  RESULTS
  All measures were significantly lower in AD patients compared with controls. NAA/Cr and NAA correlated weakly, and there was no correlation of NAA with the amount of BT in the voxel. The highest specificity (87%) at a sensitivity of 80% was observed for NAA multiplied with the amount of BT in the voxel. There was no correlation of the MMSE with any of the NAA parameters.
  
  
  CONCLUSIONS
  NAA/Cr does not reflect NAA concentration very well. NAA is not correlated with brain atrophy. The BT volume in the 1H-MRS voxel in combination with the concentration of NAA discriminates AD from healthy controls sufficiently.
authors: Department of Psychiatry, University of Bonn, Bonn, Germany.
authors: Frank
authors: F
authors: Jessen
authors: Frank
authors: F
authors: Traeber
authors: Nikolaus
authors: N
authors: Freymann
authors: Wolfgang
authors: W
authors: Maier
authors: Hans-H
authors: HH
authors: Schild
authors: Reinhard
authors: R
authors: Heun
authors: Wolfgang
authors: W
authors: Block
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000378:metabolism*; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D013702:Temporal Lobe / Q000378:metabolism*
chemical_list: D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline