A comparative study of the different N-acetylaspartate measures of the medial temporal lobe in Alzheimer's disease.
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.
Jessen
Frank
F
Department of Psychiatry, University of Bonn, Bonn, Germany.
Traeber
Frank
F
Freymann
Nikolaus
N
Maier
Wolfgang
W
Schild
Hans-H
HH
Heun
Reinhard
R
Block
Wolfgang
W
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*
D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline