A Comparative (68)Ga-Citrate and (68)Ga-Chloride PET/CT Imaging of Staphylococcus aureus Osteomyelitis in the Rat Tibia

There may be some differences in the in vivo behavior of (68)Ga-chloride and (68)Ga-citrate leading to different accumulation profiles. This study compared (68)Ga-citrate and (68)Ga-chloride PET/CT imaging under standardized experimental models. Methods. Diffuse Staphylococcus aureus tibial osteomyelitis and uncomplicated bone healing rat models were used (n = 32). Two weeks after surgery, PET/CT imaging was performed on consecutive days using (68)Ga-citrate or (68)Ga-chloride, and tissue accumulation was confirmed by ex vivo analysis. In addition, peripheral quantitative computed tomography and conventional radiography were performed. Osteomyelitis was verified by microbiological analysis and specimens were also processed for histomorphometry. Results. In PET/CT imaging, the SUV(max) of (68)Ga-chloride and (68)Ga-citrate in the osteomyelitic tibias (3.6 ± 1.4 and 4.7 ± 1.5, resp.) were significantly higher (P = 0.0019 and P = 0.0020, resp.) than in the uncomplicated bone healing (2.7 ± 0.44 and 2.5 ± 0.49, resp.). In osteomyelitic tibias, the SUV(max) of (68)Ga-citrate was significantly higher than the uptake of (68)Ga-chloride (P = 0.0017). In animals with uncomplicated bone healing, no difference in the SUV(max) of (68)Ga-chloride or (68)Ga-citrate was seen in the operated tibias. Conclusions. This study further corroborates the use of (68)Ga-citrate for PET imaging of osteomyelitis.