Early-phase 18F-Flortaucipir tau-PET as a proxy of brain metabolism in Alzheimer’s disease: a comparison with 18F-FDG-PET and early-phase amyloid-PET

• Published in: European journal of nuclear medicine and molecular imaging Vol. 52; no. 6; pp. 1958 - 1969
• Main Authors: Boccalini, Cecilia, Peretti, Debora Elisa, Mathoux, Gregory, Iaccarino, Leonardo, Ribaldi, Federica, Scheffler, Max, Perani, Daniela, Frisoni, Giovanni B., Garibotto, Valentina
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.05.2025; Springer Nature B.V
• Subjects: Alzheimer's disease; Biomarkers; Brain; Cardiology; Evaluation; Glucose metabolism; Hypometabolism; Imaging; Medicine; Medicine & Public Health; Metabolism; Neurodegeneration; Neurodegenerative diseases; Nuclear Medicine; Oncology; Original; Original Article; Orthopedics; Perfusion; Positron emission; Positron emission tomography; Radiology; Tau protein; Early-phase tau-PET; F-FDG PET; F-flortaucipir; Neurodegeneration; Perfusion
• ISSN: 1619-7070; 1619-7089; 1619-7089
• DOI: 10.1007/s00259-024-07063-4

Purpose As dual-phase amyloid-PET can evaluate amyloid (A) and neurodegeneration (N) with a single tracer injection, dual-phase tau-PET might be able to provide both tau (T) and N. Our study aims to assess the association of early-phase tau-PET scans and 18 F-fluorodeoxyglucose (FDG) PET and their comparability in discriminating Alzheimer’s disease (AD) patients and differentiating neurodegenerative patterns. Methods 58 subjects evaluated at the Geneva Memory Center underwent dual-phase 18 F-Flortaucipir-PET with early-phase acquisition (eTAU) and 18 F-FDG-PET within 1 year. A subsample of 36 participants also underwent dual-phase amyloid-PET (eAMY). Standardized uptake value ratios (SUVRs) were calculated to assess the correlation of eTAU and their respective 18 F-FDG-PET and eAMY scans. Hypometabolism and hypoperfusion maps and their spatial overlap were also evaluated at the individual level visually and semiquantitatively. Receiver operating characteristic analyses were performed to compare the discriminative power of eTAU, FDG, and eAMY SUVR between A-/T- and A+/T + participants. Results Strong positive correlations were found between eTAU and FDG SUVRs ( r  = 0.84, p  < 0.001) and eTAU and eAMY SUVRs ( r  > 0.87, p  < 0.001). Clusters of significant hypoperfusion with good correspondence to hypometabolism topographies were found at the individual level, independently of the underlying neurodegenerative patterns. Both eTAU and FDG SUVRs significantly distinguished A+/T + from A-/T- individuals (AUC eTAU =0.604, AUC FDG =0.748) with FDG performing better than eTAU ( p  = 0.04). eAMY and eTAU SUVR showed comparable discriminative power. Conclusion Early-phase 18 F-Flortaucipir-PET can provide perfusion information closely related to brain regional glucose metabolism and perfusion measured by early-phase amyloid-PET, even if less accurate than FDG-PET as a biomarker for neurodegeneration.