F-18 FDG-PET/CT in evaluation of patients with fever of unknown origin

This study was carried out to evaluate the diagnostic utility of FDG-PET/CT in patients with fever of unknown origin (FUO). Medical records of 103 patients who underwent FDG-PET/CT and anatomic imaging as a part of FUO workup were analyzed. Final diagnosis of the cause of FUO was reached based on serologic assays, cultures, biopsy, surgery or 6 months of clinical follow-up. The definite cause of fever was established in 69/103 patients. Abnormal FDG uptake was found in 63/103 patients and contributed to the final diagnosis (TP) in 62 patients (98.48 %). Of the remaining 40 patients with negative PET/CT, the final definite cause of fever (FN) could be determined only in seven patients (17.5 %). PET/CT had a sensitivity, specificity, positive predictive value and negative predictive value of 90, 97, 98.4 and 82.5 % compared to 43.5, 67.6, 73.2 and 37.1 %, respectively, for anatomic imaging. FDG-PET/CT had a higher accuracy (92.2 vs. 51.5 %; p = 0.003) compared to anatomic imaging for suggesting a cause of FUO. PET/CT showed high sensitivity and specificity in suggesting a definite diagnosis in the evaluation of FUO.