Amyloid load but not regional glucose metabolism predicts conversion to Alzheimer’s dementia in a memory clinic population

Purpose The value of imaging regional glucose metabolism with [ 18 F]FDG PET for the prediction of progression from mild cognitive impairment (MCI) to Alzheimer’s dementia (AD) is controversial. The predictive value of imaging with [ 18 F]FDG PET was therefore tested and compared with that of imaging beta-amyloid load with [ 11 C]PIB PET in the same memory clinic population of MCI patients. Methods Thirty-nine patients with MCI who had undergone [ 18 F]FDG as well as [ 11 C]PIB PET were identified from a single-centre clinical registry. [ 18 F]FDG and [ 11 C]PIB PET images were rated as positive or negative for the presence of regional hypometabolism typical of AD and beta-amyloid deposition, respectively. Raters were blinded to the clinical information. Patients were followed clinically for 2.7 ± 1.2 years after PET. Cox proportional hazards models, adjusted for age and sex, were used to test the predictive value of [ 18 F]FDG PET, [ 11 C]PIB PET, and both in combination. Results [ 18 F]FDG PET did not significantly predict conversion to AD ( p > 0.1). By contrast, models including [ 11 C]PIB PET only ( p