Diagnostic value of positron emission tomography combined with computed tomography for evaluating patients with septic shock of unknown origin

Purpose: (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) combined with computed tomography (CT) is a promising new tool for the identification of infectious foci. The aim of our work was to evaluate the diagnostic value of FDG-PET/CT in critically ill patients with septic shock of unknown origin.

Methods: We performed a single-center, 6-year retrospective evaluation of the value of FDG-PET/CT in critically ill patients with severe sepsis or septic shock of unknown origin.

Results: Eighteen patients underwent FDG-PET/CT. Microbiological tests (blood culture, urine, and respiratory secretions), chest x-rays, CT scans, and transesophageal echocardiography were performed on all patients before FDG-PET/CT scanning. Pathologic FDG accumulation could be demonstrated in 14 of 18 FDG-PET/CT scans. On a per-patient basis, 11 were "true positive," 3 were "false positive," 4 were true negative, and there were no false negatives. In 6 cases, the results of the PET/CT scan had direct therapeutic consequences (surgery, 2; pacemaker removal, 2; initiation of antibiotic therapy, 1; and prolonged antibiotic therapy, 1); 12 (66%) of the 18 patients survived to hospital discharge.

Conclusions: The FDG-PET/CT is a valuable tool for the localization of infectious foci in critically ill patients with severe sepsis/septic shock in whom conventional diagnostic methods fail to detect these foci. Prospective studies with more patients are warranted to further evaluate the diagnostic accuracy and feasibility of this diagnostic tool in critically ill patients with severe sepsis.