Magnetic resonance spectroscopy performance for detection of dementia, Alzheimer's disease and mild cognitive impairment in a community-based survey.
OBJECTIVE
To evaluate (1)H-labelled magnetic resonance spectroscopy (MRS) in patients with a low Mini Mental State Examination (MMSE) score identified during a dementia community-based survey.


METHODS
A population sample of 1,500 individuals (>64 years old) was randomly selected. Two hundred and fifteen individuals (MMSE < or =24) were sorted into clinical groups: dementia, Alzheimer's disease, mild cognitive impairment (MCI), normal. Up to 56 of these individuals attended the MRS appointment. Two single-voxel sequences (TR 1,500, TE 35/144 ms) were carried out in the posterior cingulate gyrus of each individual, and the ratios N-acetylaspartate (NAA)/creatine (Cr), choline (Cho)/Cr, myo-inositol (mI)/Cr, NAA/mI and NAA/Cho were compared statistically. The ability of MRS to distinguish clinical groups was assessed by receiver-operating characteristics analysis. Cognition effects on metabolite ratios were estimated, with gender and cognition as categorical variables and age as a continuous covariate.


RESULTS
NAA/Cr and NAA/Cho ratios were lower in dementia or Alzheimer's disease than in MCI and normal groups. The NAA/Cr ratio at TE 35 ms performed best when distinguishing dementia or Alzheimer's disease from non-demented subjects (cut-off point 1.40). MRS could not distinguish between MCI patients and normal subjects. Dementia was an independent predictor of metabolite values.


CONCLUSIONS
In a population sample, conventional MRS still proved to be a useful tool for dementia discrimination, but it is potentially far less useful as a surrogate marker for MCI.
Neuroradiology and Head and Neck Imaging Section, Department of Diagnostic Radiology, Hospital General Universitario Morales Meseguer, Murcia, Spain. josem.garcia11@carm.es
J M
JM
García Santos
D
D
Gavrila
C
C
Antúnez
M J
MJ
Tormo
D
D
Salmerón
R
R
Carles
J
J
Jiménez Veiga
G
G
Parrilla
S
S
Torres del Río
L
L
Fortuna
C
C
Navarro
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000378:metabolism; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001921:Brain / Q000378:metabolism; D002794:Choline / Q000378:metabolism; D003072:Cognition Disorders / Q000175:diagnosis* / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D003625:Data Collection; D003704:Dementia / Q000175:diagnosis* / Q000378:metabolism; D005260:Female; D006801:Humans; D007294:Inositol / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D011237:Predictive Value of Tests; D011522:Protons; D012111:Residence Characteristics; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
D011522:Protons; D001224:Aspartic Acid; D007294:Inositol; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline