[18F]flutemetamol amyloid positron emission tomography in preclinical and symptomatic Alzheimer's disease: Specific detection of advanced phases of amyloid-β pathology

BACKGROUND Amyloid positron emission tomography (PET) has become an important tool to identify amyloid-β (Aβ) pathology in Alzheimer's disease (AD) patients. Here, we determined the diagnostic value of the amyloid PET tracer [(18)F]flutemetamol in relation to Aβ pathology at autopsy. METHODS [(18)F]flutemetamol PET was carried out in a cohort of 68 patients included in a [(18)F]flutemetamol amyloid PET imaging end-of-life study (GE067-007). At autopsy, AD pathology was determined and Aβ plaque pathology was classified into phases of its regional distribution (0-5). RESULTS [(18)F]flutemetamol PET was universally positive in cases with advanced stage postmortem Aβ pathology (Aβ phases 4 and 5). Negative amyloid PET was universally observed in nondemented or non-AD dementia cases with initial Aβ phases 1 and 2, whereas 33.3% of the phase 3 cases were positive. CONCLUSIONS [(18)F]flutemetamol amyloid PET detects primarily advanced stages of Aβ pathology in preclinical and symptomatic AD cases.