Application of 18F-FDG PET/CT in the diagnosis of extrapulmonary tuberculosis

Objective This study aimed to evaluate the diagnostic value of positron emission tomography/computed tomography(PET/CT) for detecting the infective lesions in patients with extrapulmonary tuberculosis (EPTB). Methods The PET/CT imaging findings of 46 patients with extrapulmonary tuberculosis were analyzed retrospectively. Of the 46 patients, the standard uptake value (SUV) was calculated, and the maximum SUV (SUVmax) was measured. Characteristic imaging findings and SUV of EPTB in PET/CT were summarized. Results PET/CT demonstrated different degrees of increased 18F-FDG uptake in EPTB patients, with the SUVmax ranging from 1.3 to 30.0. Based on the involved organ and tissue, there were 4 types of lesions, including lymph node tuberculosis (25 cases), membranous tuberculosis (13 cases), organ tuberculosis (13 cases) and osteoarticular tuberculosis (8 cases). Of the 46 cases, 11 had two or more than two types of lesions. In the 25 cases of lymph node tuberculosis, slight or moderate lymphadenopathy were revealed by CT, and nodular or mass-like increased 18F-FDG uptake were found by PET, with SUVmax ranged from 3.0 to 30.0. In the 13 cases of membranous tuberculosis, the lesions involved meninx, pericardium, pleura and peritoneum. And PET/CT demonstrated different degrees of membranous thickening, with the SUVmax ranging from 1.3 to 14.5. In the 13 cases of organ tuberculosis, the lesion involved liver, spleen, pancreas, colon, prostate, seminal vesicle and ovary, with the SUVmax ranging from 2.5 to 15.6. In the 8 cases of osteoarticular tuberculosis, osteolytic bone destruction was found. The lesions showed increased 18F-FDG uptake on the PET/CT, with SUVmax ranging from 3.5 to 19.2. Conclusion There were some imaging characteristics of EPTB by PET/CT. PET/CT can accurately demonstrate the pathological morphology, extent of involvement and uptake activity of EPTB, and provided information in accurate diagnosis, differential diagnosis and assessment of treatment response of EPTB.