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

Braz J Psychiatry. 2022 Aug 15;44(5):495-506. doi: 10.47626/1516-4446-2021-2374.


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.

Keywords: Positron emission tomography; [11C]-labeled Pittsburgh compound B; [18F]fluoro-2-deoxy-d-glucose; aging; amyloid; cerebral glucose metabolism; neuroimaging; perfusion.

MeSH terms

  • Aged
  • Alzheimer Disease* / diagnostic imaging
  • Alzheimer Disease* / metabolism
  • Amyloid beta-Peptides
  • Brain / diagnostic imaging
  • Brain / pathology
  • Carbon Radioisotopes / metabolism
  • Fluorodeoxyglucose F18 / metabolism
  • Humans
  • Positron-Emission Tomography / methods


  • Fluorodeoxyglucose F18
  • 2-(4'-(methylamino)phenyl)-6-hydroxybenzothiazole
  • Carbon-11
  • Carbon Radioisotopes
  • Amyloid beta-Peptides