Regional metabolic patterns in mild cognitive impairment and Alzheimer's disease: A 1H MRS study.
BACKGROUND
Mild cognitive impairment (MCI) is a recently described transitional clinical state between normal aging and AD. Assuming that amnestic MCI patients had pathologic changes corresponding to an early phase and probable AD patients to a later phase of the disease progression, the authors could approximate the temporal course of proton MR spectroscopic (1H MRS) alterations in AD with a cross-sectional sampling scheme.


METHODS
The authors compared 1H MRS findings in the superior temporal lobe, posterior cingulate gyri, and medial occipital lobe in 21 patients with MCI, 21 patients with probable AD, and 63 elderly controls. These areas are known to be involved at different neurofibrillary pathologic stages of AD.


RESULTS
The N-acetylaspartate (NAA)/creatine (Cr) ratios were significantly lower in AD patients compared to both MCI and normal control subjects in the left superior temporal and the posterior cingulate volumes of interest (VOI) and there were no between-group differences in the medial occipital VOI. Myoinositol (MI)/Cr ratios measured from the posterior cingulate VOI were significantly higher in both MCI and AD patients than controls. The choline (Cho)/Cr ratios measured from the posterior cingulate VOI were higher in AD patients compared to both MCI and control subjects.


CONCLUSIONS
These findings suggest that the initial 1H MRS change in the pathologic progression of AD is an increase in MI/Cr. A decrease in NAA/Cr and an increase in Cho/Cr develop later in the disease course.
Kantarci
K
K
Departments of Diagnostic Radiology, Mayo Clinic, Rochester, MN, USA.
Jack
C R
CR
Xu
Y C
YC
Campeau
N G
NG
O'Brien
P C
PC
Smith
G E
GE
Ivnik
R J
RJ
Boeve
B F
BF
Kokmen
E
E
Tangalos
E G
EG
Petersen
R C
RC
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis / Q000503:physiopathology*; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001931:Brain Mapping; D002794:Choline / Q000378:metabolism; D003072:Cognition Disorders / Q000175:diagnosis / Q000503:physiopathology*; D003401:Creatine / Q000378:metabolism; D018450:Disease Progression; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006179:Gyrus Cinguli / Q000503:physiopathology; D006801:Humans; D007294:Inositol / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009483:Neuropsychological Tests; D009778:Occipital Lobe / Q000503:physiopathology; D012016:Reference Values; D013702:Temporal Lobe / Q000503:physiopathology
D001224:Aspartic Acid; D007294:Inositol; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline