Diagnostic contribution of 18F-FDG-PET/CT in fever of unknown origin

Objectives: Fever of unknown origin (FUO) remains one of the most compelling diagnostic issues in medicine. We aimed to evaluate the potential clinical contribution of 18-fluoro-2-deoxyglucose positron emission tomography/computed tomography (F-18-FDG-PET/CT) in the identification of the underlying cause of FUO. Methods: Fifty consecutive patients (27 men and 23 women; age range 16-88 years) with FUO based on the revised definition criteria were included in the study. A diagnostic protocol including biochemistry, histopathology, and microbiological tests was performed and the patients were followed up. FDG-PET was performed in 25 of the 50 patients (12 males and 13 females; age range 16-88 years) in order to determine the etiology of the patient's fever. PET-CT images were obtained with the Gemini Philips TF F-18-FDG-PET/CT camera after a 60-min 'standard uptake' period following an injection of a mean 330 MBq (range 290-370 MBq) intravenous F-18-FDG. Results: A total of 21 patients were available for analysis of the diagnostic contribution of PET/CT (two patients were undiagnosed and two had non-contributory PET/CT findings). F-18-FDG-PET/CT was able to precisely detect the cause of fever in 60% of the cases (n = 15). The accuracy, sensitivity, and specificity of this imaging modality were 90.5%, 93.8%, and 80%, respectively. Among the cases with a true-positive F-18-FDG-PET/CT finding (i.e., 15 cases), the identified underlying causes of FUO included localized infection (n = 7), non-infective inflammatory process (n = 5), and malignancy (n = 3). Conclusions: Further studies to confirm the high diagnostic yield of F-18-FDG-PET/CT observed in the present study would lend support to the inclusion of this imaging modality in the initial diagnostic workup of patients with suspected FUO. (C) 2013 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. All rights reserved.