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

PURPOSE: This study evaluated the potential of (68)Ga-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-[(18)F]fluoro-2-deoxy-D-glucose ((18)F-FDG) PET/CT. METHODS: Four patients admitted to hospital due to S. aureus bacteraemia underwent both (18)F-FDG and (68)Ga-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 (18)F-FDG and (68)Ga-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 (18)F-FDG (maximum standardised uptake value [SUV(max)] 6.0 ± 1.0) and (68)Ga-citrate (SUV(max) 6.8 ± 3.5, P = 0.61). Three patients had soft tissue infectious foci, with more intense (18)F-FDG uptake (SUV(max) 6.5 ± 2.5) than (68)Ga-citrate uptake (SUV(max) 3.9 ± 1.2, P = 0.0033). CONCLUSIONS: Our small cohort of patients with S. aureus bacteraemia revealed that (68)Ga-citrate PET/CT is comparable to (18)F-FDG PET/CT for detection of osteomyelitis, whereas (18)F-FDG resulted in a higher signal for the detection of soft tissue infectious foci.