Evaluation of early-phase ¹⁸ F-Florbetaben PET as a surrogate biomarker of neurodegeneration: In-depth comparison with ¹⁸ F-FDG PET at group and single patient level

BackgroundImaging biomarkers are essential in Alzheimer's disease (AD) diagnosis, particularly since the introduction of the ATN criteria by the NIA-AA. These criteria include amyloid-β plaques (amyloid PET), fibrillar tau (tau PET), and neurodegeneration (FDG PET or MRI). Early-phase amyloid PET imaging has shown a strong correlation with FDG PET at the group level.ObjectiveThis study evaluates the comparability of early-phase FBB PET (eFBB) perfusion imaging and FDG PET metabolic imaging at both group and individual levels.MethodsA retrospective study included 103 patients with mild cognitive impairment (MCI) or mild dementia suspected of AD who underwent FDG PET and dual-phase ¹⁸F-Florbetaben PET (including a 5-min eFBB scan) between 2019 and 2023, along with 33 healthy controls. Imaging analyses included qualitative, semi-quantitative, and voxel-wise techniques to compare eFBB and FDG PET scans.ResultseFBB and FDG PET SUVR values showed a strong correlation across all brain regions (rho = 0.879). Visual assessments of eFBB and FDG PET by two raters achieved intra-observer agreement rates of 87.5% and 86.4%, respectively. Voxel-wise analysis revealed moderate to good overlap, as indicated by Dice-Sørensen coefficients, in the MCI and mild dementia groups. Discriminative performance between eFBB and FDG PET was comparable, with no significant differences as eFBB reliably reflected brain metabolic patterns observed on FDG PET, supporting its diagnostic utility.ConclusionseFBB PET could serve as a surrogate biomarker for FDG PET in the diagnostic evaluation of neurodegenerative dementias. Dual-phase amyloid PET enables simultaneous assessment of neurodegeneration and amyloid burden, offering a streamlined and resource-efficient approach for clinical practice.