Abstract：Objective: To assess the clinical value of 18F-FDG PET imaging in diagnosing fever of unknown origin(FUO). Methods: Twenty-four in-patients diagnosed as FUO were enrolled in this study. They met the diagnostic criteria of FUO as fever higher than 38.3°C documented on several occasions and persisting without diagnosis for at least 3 weeks in spite of investigation for at least 1 week. Whole body 18F-FDG PET was performed in these patients. Final diagnosis was made when patients were discharged. Results: Twenty-four patients were divided into three groups according to the results of their 18F-FDG PET imaging and the final diagnosis.①18F-FDG PET imaging from 10 cases can’t provide useful information to clinical diagnosis. These included 8 cases of negative 18F-FDG PET imaging. Among them, 1 case was diagnosed as collagen disease, 1 was vascular disease, 2 cases were disease of connective tissue and another 4 cases had no final diagnosis. 2 cases had positive imaging results but without clinical specificity, including 1 case with high metabolism in bilateral hilar regions and another one with uniform hyperplasia in bone marrow. Neither of them had final diagnosis; ②four cases got useful clinical information from 18F-FDG PET imaging. These included hyper-metabolism lesions in bone marrow, detection of lymph nodes in neck and local hyper-metabolic lesions in liver. Final diagnosis were hepatic hemangioma with infection, myelodysplastic syndrome, myeloid leukemia, respectively; ③ten cases were strongly suspected as malignant diseases, including 1 case of colon leiomyosarcoma, 1 case of colon cancer and 1 case of nasopharyngeal cancer. 2 cases with multiple bone metastatic lesions with unknown origin. Five cases had remarkable F-FDG uptake in abdomen, among them, 3 cases were diagnosed as lymphoma and confirmed by pathology, 1 case was lymphadenitis and another case had inflammation of gallbladder fossa. Conclusion: 18F-FDG PET imaging can make contribution to clinical diagnosis of FUO. The sensitivity was 58.3%(14/24). Among them, malignant disease was as high as 71.4%(10/14) due to the case number of hematological malignant disease in the studied cohort.
2006, Vol. 17 
