Abstract: Objective To investigate the image performance of ¹⁸F-FDG PET/CT in extrapulmonary tuberculosis and to improve its overall understanding. Methods 12 extrapulmonary tuberculosis patients were enrolled in this study, of which 10 were diagnosed by histopathology, 1 by witness of tuberculosis bacillus in ascites sample and 1 by clinical data. All patients underwent whole body ¹⁸F-FDG PET/CT imaging. Results Lymphatic tuberculosis(5 cases), Osteoarticular tuberculosis(4 cases), Pleural and peritoneal tuberculosis(2 cases), Intestinal tuberculosis(1 case) were confirmed. Lymphatic tuberculosis was found to be with lymph node enlargement (edge blur, partial fusion) and different degree of FDG uptake. Osteoarticular tuberculosis was found to have osteolytic destruction, with or without cold abscess, of which 2 cases showed high FDG uptake without bone destruction, 1 case of thoracic tuberculosis, 1 case of multiple bone tuberculosis, 1 case of pulmonary tuberculosis with multiple lymphnode tuberculosis, osteoarticular tuberculosisand spleen tuberculosis, and 1 case of sternoclavicular joint tuberculosis. Pleural and peritoneal tuberculosis were present with different degree of pleural and peritoneal effusion. pleural effusion showed no FDG uptake, peritoneal effusion showed lines and nodules FDG uptake.1intestinal tuberculosis with pulmonary tuberculosis, nodular thickening in ileocecal junction(Blurred the surrounding fat), nodules FDG uptake. Conclusion Extrapulmonary tuberculosis usually showed FDG uptake, imaging and metabolic activity are similar to tumors and can be easily misdiagnosed.

Key words: Tuberculosis, ¹⁸F-FDG, PET/CT