Diagnostic value of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in patients with fever of unknown origin

Background: While fever of unknown origin (FUO) remains a challenging problem in clinical practice, fluorine-18 fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) has been considered helpful in diagnosing its cause. The present study is set to evaluate the diagnostic value of PET/CT for patients with FUO. Methods: We analyzed the records of 48 patients with FUO (34 men and 14 women; mean age of 57-year-old with a range between 24- and 82-year-old). The patients were examined by (18)F-FDG PET/CT and the results were compared to a final diagnosis that was established by additional procedures. Results: A final diagnosis was established for 36 patients (75%). Among them, 15 patients had infectious diseases, 12 patients had malignancies, and 9 patients had non-infectious inflammatory diseases. Thirty-two abnormal PET/CT results correctly revealed the source of fever (true-positives). Abnormal PET/CT results were considered false-positives for 8 patients without diagnoses. Normal PET/CT results in 4 patients with no diagnoses were classified as true-negatives. Four patients with normal PET/CT results with diagnosed cause for FUO were considered false-negatives. Therefore, PET/CT had a positive predictive value of 80%, a negative predictive value of 50%, a sensitivity of 89%, and a specificity of 33% in patients with FUO. Conclusions: Our study demonstrated that FDG-PET/CT is a valuable imaging tool for the identification of the etiology in patients with FUO. The results suggest that this procedure may be considered as a second-line test, especially when conventional structural imaging was normal or unable to distinguish lesions from benign and malignant. (C) 2010 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.