["Clinical positron emission tomography (PET) may help in the evaluation of presenile patients with memory complaints for the presence of Alzheimer's disease (AD).", 'Clinical PET scans from 27 patients with clinically probable AD and early ages of onset (<65 years) were compared to PET scans from 27 age-matched controls presenting with memory complaints, but without dementia or mild cognitive impairment.', 'Compared to controls, the AD patients had significant frontal, temporal and parietal hypometabolism bilaterally, and AD diagnosis correlated with left temporal and right temporoparietal hypometabolism. The sensitivity of temporoparietal hypometabolism for AD was 92.6%, the specificity 85.2%.'] Does positron emission tomography facilitate diagnosis of early-onset Alzheimer 's disease?