Acurácia diagnóstica do 18F-FDG-PET na sepse abdominal em ratos

Abstract

Background and Purpose: Positron Emission Tomography (18F-FDG-PET) is increasingly used for the diagnosis and monitoring of cancer treatment, and has shown promising results in the identification of infectious foci in patients with fever of unknown origin. However, data on the use of this imaging test in cases of abdominal sepsis are scarce. The objective of this study was to investigate the accuracy of Positron Emission Tomography (18F-FDG-PET) in the diagnosis of multibacterial abdominal sepsis by cecum ligation and puncture (CLP) in rats. Methods: Adult Wistar rats (Rattus norvegicus), weighing 227±35g, were allocated into a sepsis group by CLP (n=10) and sham group (n=10). 18F-FDG-PET using microPET was performed on all rats after 24 hours. Results: All animals survived for postoperative 24h. The abdomen/liver ratio of the standardized uptake value (SUV) percentage was significantly higher in the sepsis group than in the sham (p=0.004). The ROC curve showed an accuracy of 18F-FDG-PET to detect abdominal sepsis of 88.9% (p=0.001), sensitivity of 90% and specificity of 88.9%. When a cutoff point of 79% of the ratio between the SUV on the abdominal region and liver was established, the sensitivity was 90%, specificity of 88.9%; it was observed positive and negative predictive values of 90.0% and 88.9%, respectively. Conclusion: The diagnostic accuracy of 18F-FDG-PET in rats with abdominal sepsis was significantly high. It was also demonstrated the predictive ability of the abdomen/liver SUV ratio to diagnose abdominal sepsis. These findings may have implications for the clinical setting, given the high capacity to locate septic foci with micro 18F-FDG-PET.