F-18-fluorodeoxyglucose positron emission tomography combined with CT in critically ill patients with suspected infection

PURPOSE: To assess the value of F-18-fluorodeoxyglucose positron emission tomography (FDG-PET) combined with CT in critically ill patients suspected of having an infection. METHODS: FDG-PET CT scans requested for evaluation of a suspected infection or inflammatory process in critically ill, mechanically ventilated patients were analyzed (blinded for the final clinical diagnosis) and compared with clinical follow-up. RESULTS: Thirty-five FDG-PET/CT scans performed in 33 ICU patients (28 adults and 5 children), median age 58 years (range 1 month–72 years), were analyzed. Twenty-one FDG-PET/CT scans were true positive. Three FDG-PET/CT scans were considered false positive, in one case leading to additional diagnostic procedures (specificity 79%). Additionally, 11 true negatives were found (sensitivity 100%), leading to an overall accuracy of 91%. CONCLUSIONS: FDG-PET/CT scanning is of additional value in the evaluation of suspected infection in critically ill patients in whom conventional diagnostics did not lead to a diagnosis. Apart from the high accuracy, in this study it appeared that, in addition to conventional diagnostic techniques that were routinely performed, a normal FDG-PET/CT ruled out important infections requiring prolonged antibiotic therapy or drainage. Since sensitivity is lower in highly metabolic active tissues (e.g., endocarditis, meningitis), the FDG-PET/CT scan is not suited to detect infections in these tissues.