Scintigraphic imaging with technetium-99M-labelled ceftizoxime is a reliable technique for the diagnosis of deep sternal wound infection in rats.

PURPOSE To evaluate whether scintigraphy with technetium-99m-labeled ceftizoxime ((99m)Tc-CFT) can differentiate mediastinitis from aseptic inflammation associated with sternotomy. METHODS Twenty female Wistar rats were randomly distributed into four groups: S (control) -partial upper median sternotomy with no treatment; SW (control) - sternotomy and treatment of sternal wounds with bone wax; SB - sternotomy and infection with Staphylococcus aureus; SWB - sternotomy with bone wax treatment and bacterial infection. Scintigraphy with (99m)Tc-CFT was performed eight days after surgery and images were collected 210 and 360 min after infusion of the radiopharmaceutical. RESULTS No animals exhibited clinical signs of wound infection at the end of the experiment, although histological data verified acute inflammatory response in those experimentally infected with bacteria. Scintigraphic images revealed that tropism of (99m)Tc-CFT to infected sternums was greater than to their non-infected counterparts. Mean counts of radioactivity in bacteria-infected sternal regions (SB and SWB) were significantly higher (p = 0.0007) than those of the respective controls (S and SW). CONCLUSION Scintigraphy with technetium-99m-labeled ceftizoxime is a method that can potentially detect infection post sternotomy and differentiate from aseptic inflammation in animals experimentally inoculated with S. aureus.