[18F]FDG-PET in patients with Alzheimer's disease: marker of disease spread.
BACKGROUND
It is not known yet whether temporoparietal glucose hypometabolism in patients with probable Alzheimer's disease (AD) reflects disease severity or different subtypes of patients.


METHODS
Twenty-five subjects with mild probable AD [NINCDS-ADRDA criteria; age 65.8 +/- 9.3 years (mean +/- SD); Mini-Mental State Examination (MMSE) 26.0 +/- 3.3] were investigated. [(18)F]FDG-PET data were analyzed visually with raters blinded to the diagnosis and with a quantitative analysis in the region of interest on individual anatomically normalized PET scans.


RESULTS
Thirteen of 25 patients showed temporoparietal hypometabolism on visual inspection (PET+; age 65.7 +/- 10.7), 12 patients had normal FDG-PET results (PET-; age 65.9 +/- 8.0; n.s.). The MMSE and immediate reproduction of the Wechsler Memory Scale (WMS-R-I) were 27.7 +/- 1.9 and 31.1 +/- 6.1 in the PET- vs. 24.5 +/- 3.6 (p = 0.012) and 22.0 +/- 7.4 (p = 0.006) in the PET+ group. Immediate and delayed recall in the California Verbal Learning Test and delayed reproduction in the Wechsler Memory Scale were alike. Regression analysis revealed a significant correlation of temporoparietal glucose metabolism with the block span (r = 0.60; p < 0.01) and the WMS-R-I (r = 0.68; p < 0.01) but not with measures of hippocampal function.


CONCLUSIONS
Temporoparietal glucose metabolism in patients with very mild AD is a sign of disease spread beyond the temporal lobe. This may aid in establishing objective parameters for future therapeutic studies.
Bittner
D
D
Memory Clinic, University of Ulm, Ulm, Germany.
Grön
G
G
Schirrmeister
H
H
Reske
S N
SN
Riepe
M W
MW
D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging*; D000647:Amnesia / Q000000981:diagnostic imaging; D001786:Blood Glucose / Q000378:metabolism*; D001921:Brain / Q000000981:diagnostic imaging*; D018450:Disease Progression; D005260:Female; D019788:Fluorodeoxyglucose F18; D006624:Hippocampus / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D008609:Mental Status Schedule; D008875:Middle Aged; D010296:Parietal Lobe / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography; D013223:Statistics as Topic; D013702:Temporal Lobe / Q000000981:diagnostic imaging
D001786:Blood Glucose; D019788:Fluorodeoxyglucose F18