Diagnostic role of 11C-Pittsburgh compound B retention patterns and glucose metabolism by fluorine-18-fluorodeoxyglucose PET/CT in amnestic and nonamnestic mild cognitive impairment patients

OBJECTIVE Amyloid imaging clinically is usually reported as positive or negative, and the role of amyloid topography has not been studied before. To evaluate in a clinical setting the regional distribution patterns of C-Pittsburgh compound B (C-PIB) and the fluorine-18-fluorodeoxyglucose (F-FDG) uptake in patients with mild cognitive impairment (MCI), we designed this study. METHODS We studied 81 consecutive MCI patients, 64 amnestic (A-MCI) and 17 nonamnestic (NA-MCI) by C-PIB and F-FDG PET/computed tomography, by visual analysis. PIB retention was classified according to the regional distribution into the following patterns: A (frontal, lateral temporal, basal ganglia and anterior cingulate) and B (global retention). F-FDG images were considered positive only if temporoparietal hypometabolism consistent with Alzheimer's disease was observed. RESULTS In 42 of the 64 A-MCI, C-PIB was positive. Twelve of the 42 positive A-MCI showed an A-pattern, all F-FDG negative, and 30 a B-pattern, 10 F-FDG positive and 20 F-FDG negative. Of the 17 NA-MCI, C-PIB was positive in three and F-FDG was positive in one. The different proportion of C-PIB positivity in A-MCI and NA-MCI was highly significant (P