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

Abstract

There may be some differences in the in vivo behavior of Ga-68-chloride and Ga-68-citrate leading to different accumulation profiles. This study compared Ga-68-citrate and Ga-68-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 Ga-68-citrate or Ga-68-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 SUVmax of Ga-68-chloride and Ga-68-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 SUVmax of Ga-68-citrate was significantly higher than the uptake of Ga-68-chloride (P = 0.0017). In animals with uncomplicated bone healing, no difference in the SUVmax of Ga-68-chloride or Ga-68-citrate was seen in the operated tibias. Conclusions. This study further corroborates the use of Ga-68-citrate for PET imaging of osteomyelitis.