Performance and value of ¹⁸F‑FDG PET/CT in patients with fever of unknown origin

Fever of unknown origin (FUO) is a common clinical and diagnostic challenge. The main aim of the present study was to evaluate the diagnostic accuracy of ¹⁸F-fluorodeoxyglucose (¹⁸FDG) positron emission tomography (PET)/CT in patients who present with FUO. Overall, 105 consecutive patients (61 men and 44 women) with a mean age of 51±35 years with FUO underwent ¹⁸FDG PET/CT scans. The performance of ¹⁸FDG PET/CT in determining the etiology of FUO was assessed. According to the PET/CT results, patients were classified into four groups: Group 1, patients with true-positive results (n=51; 49%), in whom abnormal ¹⁸FDG uptake identified the final diagnosis; group 2, patients with false-positive results (n=24; 23%), in whom ¹⁸FDG uptake was not consistent with the final diagnosis; group 3, patients with true-negative results (n=10; 9.5%), in whom the ¹⁸FDG uptake was normal and no final disease was established; and group 4, patients with false-negative results (n=20; 19%), in whom ¹⁸FDG uptake was normal and disease was finally established. Of the 51 patients with true-positive PET/CT results, 51% had infections, 35% had malignancies and 14% had inflammatory processes. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 72, 29, 68, 33 and 58%, respectively. In conclusion, the present results demonstrated that ¹⁸FDG PET/CT established the final diagnosis of FUO in the majority of patients (72%). These results support the use of ¹⁸FDG PET/CT in the initial evaluation and management of patients with FUO.