Usefulness of 18F‐FDG PET‐CT for the management of invasive fungal infections: A retrospective cohort from a tertiary university hospital

Background 18F‐FDG PET‐CT is a potentially useful technique to help manage invasive fungal infection (IFI), but information on this topic is scarce. Objectives To describe our experience using 18F‐FDG PET‐CT for IFI management. Patients/Methods Retrospective cohort of IFI episodes in a university hospital from 2018 to 2023 with a18F‐FDG PET‐CT performed during the episode. We analysed its impact on IFI management compared to conventional imaging. Results Thirty‐five patients diagnosed with 36 episodes of IFI (52.8% moulds, 44.4% yeasts and 2.8% Pneumocystis) underwent 55 18F‐FDG PET‐CT. 74.3% were immunocompromised, including 45.7% solid organ transplant recipients. Indications for 18F‐FDG PET‐CT were diagnostic (10.9%), staging (47.3%) and follow‐up (41.8%). Altogether 18F‐FDG PET‐CT added value to IFI management in 50.9% episodes. In 26 patients who had both staging 18F‐FDG PET‐CT and conventional imaging, sites of IFI dissemination were detected in 53.8% and 19.2%, respectively. Staging 18F‐FDG PET‐CT unveiled occult sites in 34.6%, uncovering unknown dissemination in 19.2%. In the evaluation of endocarditis in patients with fungemia, it contributed in at least 38.5%. Follow‐up 18F‐FDG PET‐CTs had an added value in 47.8% episodes. They were allowed to de‐escalate antifungal therapy in 26.1%. There were discordant findings between 18F‐FDG PET‐CT and CT follow‐up in 40% cases. Conclusions Overall, 18F‐FDG PET‐CT added value to IFI management in more than 50% of the episodes. It increased the diagnosis of occult sites, unveiled disseminated disease missed out by conventional imaging, and contributed to diagnose or rule out endocarditis in fungemia. Follow‐up 18F‐FDG PET‐CT helped adjust the treatment duration and deserves further study.