RESUMEN
OBJECTIVE: To review the findings on (18)F-FDG PET-CT in patients with fever of unknown origin lasting more than 7 days. MATERIAL AND METHODS: This retrospective descriptive observational study included 93 (18)F-FDG PET-CT studies to detect a fever-causing focus done at three nuclear medicine centers from October 2006 through February 2014. A nuclear medicine specialist and a radiologist reviewed the images for foci of pathological uptake; another specialist's opinion resolved discrepancies. The findings on (18)F-FDG PET-CT studies were checked against clinical and/or histological findings. RESULTS: Abnormal (18)F-FDG uptake on PET-CT that could explain the cause of the fever was found in 52 (56%) of the 93 studies, and the cause of the fever was confirmed in 50 of these 52 studies. In the 50 cases in which the cause of the fever was confirmed, infection was the most common cause (54%), followed by noninfectious inflammatory disease (28%) and tumors (18%). CONCLUSION: (18)F-FDG PET-CT is useful in diagnosing the cause of prolonged febrile illness, so it might be practical to use it earlier in the diagnostic process.