Amyloid imaging with (11)C-PIB PET/CT and glucose metabolism with (18)F-FDG PET/CT in a study on cognitive impairment in the clinical setting.

OBJECTIVE: The objective of this study was to evaluate the contribution of amyloid imaging with (11)C-Pittsburgh compound B ((11)C-PIB) and of glucose metabolism on F-fluorodeoxyglucose ((18)F-FDG) PET/CT to the study of cognitive impairment in the clinical setting.

PATIENTS AND METHODS: Thirty-four patients (15 male, 19 female) were enrolled in the study. They were classified according to their clinically presented symptoms. Six patients had subjective memory complaints, five had nonamnestic mild cognitive impairment (MCI), seven had amnestic MCI, seven had prodromal Alzheimer's disease (AD), five had frontotemporal dementia, two had dementia with Lewy bodies, and two had cortical degeneration. All the scans were conducted to determine the likelihood of AD or to differentiate between AD and other dementia. Static 30-min (11)C-PIB and 15-min (18)F-FDG PET/CT scans were obtained. A visual analysis of images was performed.

RESULTS: Three of the six patients with subjective memory complaints had positive (11)C-PIB scans and one of them also had (18)F-FDG hypometabolism. All five nonamnestic MCI patients had normal (11)C-PIB and (18)F-FDG. Four of the seven amnestic MCI patients showed (11)C-PIB cortical retention but only one had positive (18)F-FDG. Positive (11)C-PIB and (18)F-FDG were detected in five of the seven prodromal AD patients. All the five patients with FDT had positive (18)F-FDG scans, but only one of the five had (11)C-PIB cortical retention. Both dementia with Lewy bodies and cortical degeneration patients had positive (11)C-PIB and (18)F-FDG scans.

CONCLUSION: The combined use of (11)C-PIB and (18)F-FDG PET provides relevant information for the clinical management of cognitive impairment. The detection of positive (11)C-PIB cortical retention in patients may be an indicator of the need for further clinical assessment and monitoring.