Regional uptakes from early-frame amyloid PET and 18F-FDG PET scans are comparable independent of disease state

Alison Myoraku,Duygu Tosun,Susan Landau,Gregory Klein

doi:10.1186/s41824-021-00123-0

Abstract

PurposePositron emission tomography (PET) imaging with amyloid-beta (Aβ) tracers and 2-[18F] fluoro-2-Deoxy-d-glucose (18F-FDG) is extensively employed in Alzheimer’s disease (AD) studies as biomarkers of AD pathology and neurodegeneration. To reduce cost and additional burdens to the patient, early-frame uptake during Aβ PET scanning has been proposed as a surrogate measure of regional glucose metabolism. Considering the disease state specific impact of AD on neurovascular coupling, we investigated to what extent the information captured in the early frames of an Aβ-PET (18F-florbetapir or 18F-florbetaben) scan is comparable to that of a 18F-FDG PET scan, independent of disease state.MethodA partial correlation was performed on early-frame 18F-florbetapir and 18F-FDG regional data from 100 participants. In a secondary analysis, we compared 92 18F-florbetapir and 21 18F-florbetaben early-frame Aβ scans from cognitively unimpaired and mild cognitive impairment participants to ascertain if regional early-frame information was similar across different Aβ-PET radioligands.ResultsThe partial correlation of early-frame 18F-florbetapir with 18F-FDG was significant in all 84 brain ROIs, with correlation values ranging from 0.61 to 0.94. There were no significant differences between early-frame 18F-florbetapir and 18F-florbetaben images.ConclusionOverall, we find that the regional uptake measurements from early-frame 18F-florbetapir are strongly correlated with regional glucose metabolism as measured in ground-truth 18F-FDG PET scans, regardless of disease state. Future studies should focus on longitudinal early-frame amyloid PET imaging studies to further assess the value of early-frame imaging as a marker of brain metabolic decline.

Highlights

Alzheimer’s disease (AD), the most common form of dementia, is a debilitating neurodegenerative disease that affects approximately 14.5% of the American population (Rajan et al 2019)
Overall, we find that the regional uptake measurements from early-frame 18F-florbetapir are strongly correlated with regional glucose metabolism as measured in ground-truth 18F-FDG positron emission tomography (PET) scans, regardless of disease state
Future studies should focus on longitudinal early-frame amyloid PET imaging studies to further assess the value of early-frame imaging as a marker of brain metabolic decline

Summary

Introduction

Alzheimer’s disease (AD), the most common form of dementia, is a debilitating neurodegenerative disease that affects approximately 14.5% of the American population (Rajan et al 2019). AD is pathologically characterized by amyloid-beta (Aβ) plaques and Myoraku et al European Journal of Hybrid Imaging (2022) 6:2 tau pathology (neurofibrillary tangles) which can be detected with Aβ positron emission tomography (PET) scans and used to differentiate AD from other forms of dementia. These Aβ plaques can occur as many as 10–15 years prior to the onset of observable cognitive decline and are considered an important early biomarker for AD prevention (Rowe et al 2010). Hypometabolism in the precuneus, posterior cingulate, and hippocampus has been observed in AD consistently, and associated with changes in synaptic density and correlated with cognitive impairment (Friedland et al 1983; Maldjian and Whitlow 2012; Minoshima et al 1997; Calsolaro and Edison 2016)

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