Clinical revenues of selective use of [18F]-FDG-PET/CT scanning in the management of Staphylococcus aureus bacteremia.

Purpose: Although [18F]-FDG-PET/CT scanning (PET/CT) is recommended for managing Staphylococcus aureus bacteremia (SAB), its added value remains debated. This study investigated the clinical revenues of selective PET/CT use in SAB by considering three consequence-categories: detection of new infection foci, performance of new interventions, and alterations in antimicrobial therapy.

Methods: All adult patients with ≥ 1 blood culture (BC) positive with Staphylococcus aureus admitted in a Dutch academic center between 2017¹¹ and 2023¹¹ were identified. Standard practice was to order PET/CT for patients with community acquired SAB and/or positive BCs after ≥ 48 h of treatment, or if multiple foci, or persistent fever, or endocarditis were present. Clinical- and laboratory data were obtained from electronic health records. Numbers-needed-to-scan (NNT-scan) were calculated for each consequence-category. Regression analyses were performed to identify variables correlated with consequence-bearing PET/CT.

Results: Of 397 SAB patients, 143 (36%) underwent PET/CT. This led to detection of new foci in 73/143 patients (NNT-scan ≈ 2), new interventions in 33/143 patients (NNT-scan ≈ 4), and a change in antimicrobial therapy in 44/143 patients (NNT-scan ≈ 3). A CRP > 200 mg/L at presentation and positive follow-up BCs at 48 h were independently associated with interventions following PET/CT (adjusted OR and 95%CI 3.2 (1.2-8.3) and 2.6 (1.0-6.7) respectively). PET/CT results instigated changes in antimicrobial therapy predominantly in patients < 65 years and those with a CRP < 100 at presentation.

Conclusions: Selective PET/CT ordering in real-life practice resulted in a relatively low NNT-scan across all consequence-categories. Further research is warranted to optimize patient selection for PET/CT using clinical parameters or profiles.