[Characteristics of extrapulmonary tuberculosis in (18)F-2-fluoro-2-deoxy-D-glucose positron emission...

The clinical manifestations and the imaging features in (18)F-2-fluoro-2-deoxy-D-glucose positron emission tomography ((18)F-FDG PET) of extrapulmonary tuberculosis were not specific and therefore it was difficult to be differentiated from malignancy. This paper tried to analyze the clinical characteristics and findings by (18)F-FDG PET-CT in extrapulmonary tuberculosis, in order to improve the diagnosis of this disease.

Thirty-nine patients with extrapulmonary tuberculosis underwent (18)F-FDG PET-CT imaging from 2003 - 2011. The diagnosis was confirmed by histopathological examination in all the cases. There were 11 males and 28 females, aging 20 - 67 (60 ± 18) years. A past history of tuberculosis was collected in 5 cases. The PET images were reviewed visually and scored semi-quantitatively with standardized uptake value. The lesions were judged by PET imaging features in conjunction with CT slices and the fused images.

Fever was present in 13 cases, and night sweating, weakness and malaise in 17 cases. Pleural effusion was found in 7 cases. Abdominal distention and masses were found in 6 cases, while neck mass was present in 2 cases. Laboratory tests showed that hypoalbuminemia, sedimentation rate increase and positive tuberculin tests were present in 15 cases. CA125 was increased in 3 cases. In PET-CT, lymph node tuberculosis manifested as single or multiple enlarged lymph nodes coalesced and calcified with significant FDG uptake, but ring-like FDG-avidity was also found in some of the lymph nodes. Pleural or peritoneal tuberculosis showed heterogeneous or nodular thickening and in a radio-tracer distribution. Bone tuberculosis manifested as osteolytic osseous destruction and paravertebral cold abscess, while focal radio-agent ring-like intense uptake was present in half the cases. In patients with intestinal tuberculosis, ileocecal circumferential or eccentric thickening was observed, with focal or diffuse high FDG activity. Tuberculosis in adrenal gland, liver, and oviducts all showed lesions with high FDG uptake.

(18)F-FDG PET-CT was helpful for the differential diagnosis of extrapulmonary tuberculosis from malignancy. Osseous and lymph node tuberculosis showed ring-like FDG uptake, which maybe of diagnostic value.