Characterization of ¹⁸ F-Fluorodeoxyglucose Uptake Pattern in Noninfected Prosthetic Heart Valves

Abstract

Background-18 F-Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) has been recently acknowledged as a diagnostic tool for prosthetic valve endocarditis, but its specificity is limited by uptake on noninfected valves. The objective of this study was to outline the main features of FDG uptake on PET/CT in patients with noninfected prosthetic heart valve (PHV). Methods and Results-Our institution's PET/CT database was reviewed to identify patients with PHV, excluding those suspected of infection or who had received antibiotic treatment. PET indication, valve location, and type (biological/ mechanical) and time from implantation were collected for each patient. Images with and without attenuation correction were considered for interpretation. The pattern of FDG uptake (absent, homogeneous, or heterogeneous) was recorded. Fifty-four PHVs (51 patients) were identified, including 32 biological valves. Indications for PET were oncology (n=26), suspicion of prosthetic valve endocarditis subsequently excluded (n=17), and history of vasculitis (n=11). A periprosthetic FDG uptake was present in 47 (87%) and 30 (56%) PHVs with and without attenuation correction, respectively, and the pattern was homogeneous in all but 4 (7%) and 3 (6%) PHVs, respectively. On quantitative analysis, maximum standardized uptake values was greater in mechanical than in biological valves

Evaluation of failed prosthetic valves in the valve‐in‐valve era: Potential for utilizing positron emission tomography/computed tomography to recognize infective endocarditis

“…However, the evaluation of prosthetic valves in PET/CT is not well defined. Noninfected prosthetic heart valves often display homogenous FDG uptake even in the absence of infection . The value of PET/CT is in cases where traditional Duke criteria can be indeterminate, such as in patients with prosthetic valves and transcatheter therapies where echocardiography may be challenging.…”

Usefulness of positron emission tomography/computed tomography in patients with valve-tube graft infection

“…A recent study has shown that non-infected prosthetic valves frequently display homogeneous 18 F-FDG uptake that may remain steady over time 17. This can be a source of false-positive results.…”

Quantification of FDG uptake in patients with a suspicion of prosthetic valve endocarditis: Part of the problem or part of the solution?

“…6 A reasonable alternative would be to agree on dedicated PET protocols for the imaging of patients with a suspicion of PVE that offer a compromise between image quality and the need for standardization of PET acquisitions, in a similar way to what has already been proposed for the imaging of atherosclerosis that present similar constraints. 7 Second, valves are subjected to important cardiac and respiratory motion. Signal quantification would certainly benefit from the development of dual cardiac and respiratory gating and motion correction of PET acquisitions.…”

“…The interpretation of PET images is the most difficult when FDG uptake is moderate in valves, because this aspect is frequently found in non-infected prosthetic valves in relation to chronic immune reactions and is hard to distinguish from active infection. 7 In this situation, additional criteria need to be taken into account such as the pattern of FDG uptake, the persistence of FDG signal on non-attenuation corrected images, the localization of the signal in relation to cardiac structures, and to morphological aspects observed on echocardiography or cardiac CTA. 10,11 In particular, the presence of focal or heterogeneous FDG signal extending outside the prosthetic contours is suggestive of infection.…”