Brain perfusion imaging predicts survival in Alzheimer's disease.
BACKGROUND
The variability of disease course in patients diagnosed with AD makes prediction of survival difficult, despite the identification of numerous predictors to date. This study evaluated the predictive utility of measurements of regional cerebral blood flow (rCBF) obtained with SPECT in a group of AD patients.


METHODS
Fifty AD patients were studied with SPECT and followed longitudinally. SPECT measures of relative rCBF were calculated by measuring radioactivity densities in dorsolateral frontal, orbitofrontal, temporal, and parietal cortex normalized to occipital cortical radioactivity density. Subjects were classified into three tertiles of rCBF ratios for each region. These rCBF ratios were used as predictors of survival in life-table and proportional hazard models to predict survival.


RESULTS
Right parietal rCBF was a significant predictor of survival in the life-table analysis, with subjects in the lowest tertile having shortest survivals. No other brain region was a significant predictor of survival. In a proportional hazards model when a variety of other potential predictors were accounted for, right parietal rCBF ratio remained a significant predictor.


CONCLUSIONS
These results demonstrate that brain perfusion in the right parietal lobe is a significant predictor of survival in patients with AD even when other predictors are taken into consideration. This suggests that SPECT perfusion imaging may provide additional useful information on disease prognosis in AD.
The Center for Functional Imaging, Lawrence Berkeley National Laboratory, and the Department of Neurology, University of California, Davis 94720, USA.
W J
WJ
Jagust
M N
MN
Haan
B R
BR
Reed
J L
JL
Eberling
D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging* / Q000401:mortality*; D002540:Cerebral Cortex / Q000098:blood supply*; D002560:Cerebrovascular Circulation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D016019:Survival Analysis; D015899:Tomography, Emission-Computed, Single-Photon