Head-to-Head Comparison of 68Ga-Citrate and 18F-FDG PET/CT for Detection of Infectious Foci in Patients with Staphylococcus aureus Bacteraemia

This study evaluated the potential of 68Ga-citrate positron emission tomography/computed tomography (PET/CT) for the detection of infectious foci in patients with Staphylococcus aureus bacteraemia by comparing it with 2-[18F]fluoro-2-deoxy-𝐷- glucose (18F-FDG) PET/CT. Methods. Four patients admitted to hospital due to S. aureus bacteraemia underwent both 18F-FDG and 68Ga-citrate whole-body PET/CT scans to detect infectious foci. Results. The time from hospital admission and the initiation of antibiotic treatment to the first PET/CT was 4–10 days. The time interval between 18F-FDG and 68Ga-citrate PET/CT was 1–4 days. Three patients had vertebral osteomyelitis (spondylodiscitis) and one had osteomyelitis in the toe; these were detected by both 18F-FDG (maximum standardised uptake value [SUVmax] 6.0 ± 1.0) and 68Ga-citrate (SUVmax 6.8 ± 3.5, 𝑃 = 0.61). Three patients had soft tissue infectious foci, with more intense 18F-FDG uptake (SUVmax 6.5 ± 2.5) than 68Ga-citrate uptake (SUVmax 3.9 ± 1.2, 𝑃 = 0.0033). Conclusions. Our small cohort of patients with S. aureus bacteraemia revealed that 68Ga-citrate PET/CT is comparable to 18F-FDG PET/CT for detection of osteomyelitis, whereas 18F-FDG resulted in a higher signal for the detection of soft tissue infectious foci.