Evaluation of 10-minute post-injection 11C-PiB PET and its correlation with 18F-FDG PET in older adults who are cognitively healthy, mildly impaired, or with probable Alzheimer's disease

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Carneiro, Camila de Godoi ; Faria, Daniele de Paula ; Coutinho, Artur Martins ; Ono, Carla Rachel ; Duran, Fabio Luis de Souza ; da Costa, Naomi Antunes ; Garcez, Alexandre Teles ; da Silveira, Paula Squarzoni ; Forlenza, Orestes Vicente ; Brucki, Sonia Maria Dozzi ; Nitrini, Ricardo ; Busatto Filho, Geraldo ; Buchpiguel, Carlos Alberto

• Document type: Journal article
• Source: Revista Brasileira de Psiquiatria; v. 44, n. 5, p. 12-pg., 2022-09-01.

Abstract

Objective: Positron emission tomography (PET) allows in vivo evaluation of molecular targets in neurodegenerative diseases, such as Alzheimer's disease. Mild cognitive impairment is an intermediate stage between normal cognition and Alzheimer-type dementia. In vivo fibrillar amyloid-beta can be detected in PET using [11C]-labeled Pittsburgh compound B (11C-PiB). In contrast, [18F] fluoro-2-deoxy-d-glucose (18F-FDG) is a neurodegeneration biomarker used to evaluate cerebral glucose metabolism, indicating neuronal injury and synaptic dysfunction. In addition, early cerebral uptake of amyloid-PET tracers can determine regional cerebral blood flow. The present study compared early-phase 11C-PiB and 18F-FDG in older adults without cognitive impairment, amnestic mild cognitive impairment, and clinical diagnosis of probable Alzheimer's disease.Methods: We selected 90 older adults, clinically classified as healthy controls, with amnestic mild cognitive impairment, or with probable Alzheimer's disease, who underwent an 18F-FDG PET, early -phase 11C-PiB PET and magnetic resonance imaging. All participants were also classified as amyloid-positive or-negative in late-phase 11C-PiB. The data were analyzed using statistical parametric mapping.Results: We found that the probable Alzheimer's disease and amnestic mild cognitive impairment group had lower early-phase 11C-PiB uptake in limbic structures than 18F-FDG uptake. The images showed significant interactions between amyloid-beta status (negative or positive). However, early -phase 11C-PiB appears to provide different information from 18F-FDG about neurodegeneration.Conclusions: Our study suggests that early-phase 11C-PiB uptake correlates with 18F-FDG, irrespective of the particular amyloid-beta status. In addition, we observed distinct regional distribution patterns between both biomarkers, reinforcing the need for more robust studies to investigate the real clinical value of early-phase amyloid-PET imaging. (AU)

• FAPESP's process: 12/50329-6 - Translational neuroscience of Alzheimer's disease: preclinical and clinical studies of b-amyloid peptide and other biomarkers
• Grantee: Geraldo Busatto Filho
• Support Opportunities: Research Projects - Thematic Grants