Imaging characteristics of adult onset Still's disease demonstrated with [sup.18]F-FDG PET/CT

The diagnosis of adult onset Still's disease (AOSD) is non-specific, and requires the exclusion of other diseases including infectious, inflammatory and malignant diseases. The current study aimed to summarize the imaging characteristics of fluorodeoxyglucose ([sup.18]F-FDG) positron emission tomography (PET)/computerized tomography (CT) in patients with AOSD. The [sup.18]F-FDG PET/CT characteristic observations of 32 patients with definite AOSD were retrospectively reviewed based on visual interpretation and the semi-quantitative index of standard uptake value of maximum (SUVmax). Among 32 patients, no normal case was observed. Abnormal FDG accumulation by the spleen, bone marrow and lymph nodes was the main observation of the PET/CT images. Totals of 27 (84.4%) and 26 cases (81.3%) were identified with diffusely elevated FDG uptake by the spleen and bone marrow, respectively, and the average SUVmax was 4.2 [+ or -] 1.1 and 4.6 [+ or -] 0.6, respectively. A total of 20 cases (62.5%) showed lymphadenopathy with FDG uptake, with the range of SUVmax from 2.2-13.9. In addition, 7 patients (21.9%) were observed to exhibit effusion without FDG uptake, 1 case presented with abnormal FDG uptake by the skin, and another by the right shoulder joint. In addition, no abnormally elevated FDG uptake by the liver or large vessels was observed. Due to non-specific imaging features, [sup.18]F-FDG PET/CT could not be directly helpful in diagnosing AOSD. However, [sup.18]F-FDG PET/CT serves important roles in evaluating the involved extent of AOSD, and guiding the biopsy of lymph nodes, bone marrow or other tissues, which may aid in the development of novel clinical management strategies. Key words: adult onset Still's disease, fluorodeoxyglucose, positron emission tomography/computerized tomography