Impact of Extracardiac [18F]FDG-PET/CT Findings on Diagnosis and Management in Patients with Suspected Infective Endocarditis

Abstract

Background/Objectives: We aimed to evaluate the incremental diagnostic and clinical impact of extracardiac findings detected by [18F]Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography ([18F]FDG-PET/CT) in patients with suspected infective endocarditis (IE). Methods: This monocentric cohort study included adult patients with bacteremia and suspected IE who underwent [18F]FDG-PET/CT. IE diagnosis was based on the 2023 Duke-ISCVID criteria. Extracardiac findings detected by [18F]FDG-PET/CT were assessed for their impact on IE diagnostic classification according to the 2023 Duke-ISCVID criteria and on clinical management. Results: Among 500 patients with bacteremia and suspected IE who underwent [18F]FDG-PET/CT, IE was diagnosed in 211 (42%) episodes. Embolic events were detected in 60 (12%) episodes, with 42 (8%) episodes representing previously unrecognized findings. Two (0.9%) of the 211 IE episodes were reclassified from possible to definite IE according to the 2023 Duke-ISCVID clinical criteria. [18F]FDG-PET/CT identified new infectious foci in 31 (6%) episodes (18 bone and joint infections and 13 vascular graft infections). Extracardiac findings on [18F]FDG-PET/CT resulted in prolongation of antibiotic treatment in 28 (6%) episodes and in a new indication for source control intervention in 23 (5%) episodes. Conclusions: Although [18F]FDG-PET/CT identified previously unrecognized embolic events in suspected IE, these findings had limited impact on IE diagnostic classification, supporting a selective rather than systematic use for embolic screening alone. However, its ability to detect occult extracardiac infectious foci may provide clinically relevant added value, particularly in patients with bacteremia of unknown source or vascular grafts.