fig1

Figure 1. A 65-year-old man with a bioprosthetic aortic valve replacement presented with a 2-month history of fever and severe asthenia, for which he had received several courses of antibiotic treatment. Initial blood cultures were negative, and echocardiography was also negative for vegetations. Since high clinical suspicion persisted, he underwent [¹⁸F]FDG PET/CT that did not show conclusive findings of IE beyond a very slight periprosthetic FDG uptake (A, arrows). He completed 6 weeks of empirical antibiotics and remained under close follow-up. Two months later, he was readmitted due to recurrent fever and blood cultures were positive for E. faecalis. Echocardiography showed slight thickening of the valve leaflets. A new PET/CT confirmed PVE (intense focal hypermetabolic periprosthetic soft tissue lesion compatible with a periprosthetic abscess (B, arrows). PET/CT under prolonged antibiotic treatment can lead to a false negative result and may not allow ruling out the diagnosis of infection with certainty. [¹⁸F]FDG PET/CT: ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography. PVE: prosthetic valve IE.