Alzheimer disease: quantitative H-1 MR spectroscopic imaging of frontoparietal brain.
OBJECTIVE
To replicate previous hydrogen-1 magnetic resonance (MR) spectroscopic imaging findings of metabolic abnormalities in patients with Alzheimer disease (AD), to verify that metabolic abnormalities are not an artifact of structural variations measured at MR imaging, to determine whether metabolic changes correlate with dementia severity, and to test whether MR imaging and MR spectroscopic imaging findings together improve ability to differentiate AD.


METHODS
MR spectroscopic imaging and MR imaging were performed in 28 patients with AD and 22 healthy elderly subjects. Spectroscopic imaging data were coregistered with MR imaging segmentation data to obtain volume-corrected metabolite concentrations.


RESULTS
Consistent with previous results, N-acetyl aspartate (NAA) levels were statistically significantly reduced in frontal and posterior mesial cortex of AD patients, presumably due to neuronal loss. NAA level reductions were independent of structural variations measured at MR imaging and, in parietal mesial cortex, were correlated mildly with dementia severity. Spectroscopic imaging findings of NAA level combined with MR imaging measures did not improve discrimination power for AD relative to that of MR imaging alone.


CONCLUSIONS
Reduced NAA levels in frontoparietal brain are of limited use for diagnosis of AD. However, they are not an artifact of structural variations and thus may provide useful information for the understanding of the pathologic processes underlying AD.
Schuff
N
N
Magnetic Resonance Unit, Department of Veterans Affairs Medical Center, San Francisco, CA 94121, USA.
Amend
D L
DL
Meyerhoff
D J
DJ
Tanabe
J L
JL
Norman
D
D
Fein
G
G
Weiner
M W
MW
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000378:metabolism; D016477:Artifacts; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000032:analysis; D001923:Brain Chemistry; D002794:Choline / Q000032:analysis; D003401:Creatine / Q000032:analysis; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged
D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline