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 [SUVmax ] 6.0 ± 1.0) and 68 Ga-citrate (SUVmax   6.8 ± 3.5, P = 0.61). Three patients had soft tissue infectious foci, with more intense 18 F-FDG uptake (SUVmax   6.5 ± 2.5) than 68 Ga-citrate uptake (SUVmax   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.