Introduction: The aim of this study is to use 3D-SSP and a population-comparable normal database to investigate the associations between amyloid deposition detected by 18Fflorbetapir PET and neurocognitive performance of participants with mild cognitive impairment (MCI) and Alzheimer's disease (AD).
Materials and methods: 18F-florbetapir PET and 18F-FDG PET imaging was prospectively performed on 78 subjects (20 cognitively healthy controls [HC], 27 MCI patients, and 31 AD patients) within 6 weeks of their neurocognitive assessments. The PET datasets from 19 HCs were used to create an NBD. The 3D-SSP analysis and Z-score mapping of 18F-florbetapir accumulations in the brain were further staged based on their accumulation patterns. Global and regional standard uptake value ratios (SUVRs) of 18Fflorbetapir were calculated using the cerebellar cortex as the normalised region. The relationships between the 18Fflorbetapir PET results, the clinical diagnoses and Thai Mini- Mental State Examination (TMSE) scores were determined.
Results: There was high agreement between the visual assessment results and the semiquantitative analysis (κ = 0.793 and 0.845). The stages of amyloid deposition were consistent with neurocognitive status across participants. Significantly higher SUVRs were found in AD than MCI and HC. Visual assessment and stage were not significantly correlated with TMSE scores. A significant negative correlation between the SUVRs and TMSE scores was partially demonstrated in MCI and AD, but not HC.
Conclusions: 3D-SSP analysis of 18F-florbetapir PET provides special patterns and intensity of beta amyloid accumulation semi-quantitatively that are associated with the diagnosis and neurocognitive performances in MCI and AD patients.