Efficacy of 99mTc-Ciprofloxacin and 67Ga-Citrate scintigraphy to discriminate infection foci induced by Staphylococcus aureus from sterile inflammation induced by Carrageenan in rat

Introduction: This study was launched to evaluate the sensitivity and specificity of 99mTc-Ciprofloxacin to distinguish infection foci induced by staphylococcus aureus and inflammation lesions induced by carrageenan in the rat foot in comparison with 67Ga-Citrate scintigraphy. Methods: The labeling and quality control of 99mTc-Ciprofloxacin kits have been performed according to the manufacturer’s instructions. A total number of 40 adult, male NMRI rats were randomly divided into two equal groups, one group for 99mTc-Ciprofloxacin and the other group for 67Ga-Citrate scintigraphy. Every group was subdivided into two groups equally. Septic lesion was induced by Staphylococcus aureus. Aseptic inflammation lesion was induced by carrageenan in the rat foot in the other group. The 99mTc-Ciprofloxacin and 67Ga-Citrate scintigraphy studies have been performed to evaluate the efficacy of radiotracers. Results: The images showed 67Ga uptake at the infection and inflammation sites. The infection foci could be visualized by 99mTc-Ciprofloxacin scintigraphy due to selective binding of ciprofloxacin to DNA gyrase of bacteria. The inflammation sites have been observed by non-specific uptake of 99mTc-Ciprofloxacin. None of both imaging studies have shown preferentially diagnosis of septic and aseptic inflammation lesions. The sensitivity, specificity and positive predictive value of both scintigraphic techniques were 100%, 50% and 50%, respectively. Conclusion: The 99mTc-Ciprofloxacin scintigraphy is sensitive for visualization of the lesion, but it could to discriminate between septic and aseptic inflammation lesions. Other modalities must be considered for interpretation of images obtained by 99mTc-Ciprofloxacin scintigraphy.