18F-fluorodeoxyglucose positron emission tomography computed tomography in patients with prosthetic heart valves: Variations in imaging findings: A review of the literature.

Imaging is a cornerstone of the diagnosis of prosthetic valve endocarditis. An abnormal 18F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) was added as a major diagnostic criterion in the 2015 European Society of Cardiology guidelines for the management of endocarditis. However, interpretation of uptake around prosthetic heart valves (PHVs) can be difficult because physiological factors and confounders may result in false-positive or false-negative results. This review provides a comprehensive overview of "normal" uptake by reviewing the literature on uptake surrounding non-infected PHVs. We will elaborate on qualitative and quantitative measures of uptake. Then, differences in uptake between different valve types, implant positions, and the natural course of uptake over time following PHV implantation will be discussed. Finally, factors possibly hampering assessment or mimicking infection are reviewed. We aim to support clinical implementation of 18F-FDG PET-CT in suspected prosthetic valve endocarditis and to provide practical guidance to the differentiation between physiological, postoperative, and pathological uptake around PHVs.