Imaging characteristics of adult onset Still’s disease demonstrated with 18F-FDG PET/CT

Objectives Adult onset Still’s disease (AOSD) is a chronic systemic inflammatory disease. The diagnosis of AOSD is non-specific, and excluded of many infectious, inflammatory and malignant diseases. In some sporadic AOSD cases, ¹⁸F-FDG PET/CT scan was reported of value in the diagnostic approach. Herein, this study aims to evaluate the imaging characteristics of ¹⁸F-FDG PET/CT in patients with AOSD.

Methods ¹⁸F-FDG PET/CT findings were reviewed in 31 patients with AOSD. PET/CT images were evaluated and analyzed based on visual interpretation and the semi-quantitative index of standard uptake value of maximum (SUVmax).

Results Among 31 patients, no normal case was observed. Abnormal FDG accumulation by spleen, bone marrow and lymph nodes was the main performance on PET/CT images. 26 cases (83.9%) were found with diffusely elevated FDG uptake by spleen, and the average SUVmax was 4.2 ± 1.1 (range, 2.5-6.7). 25 cases (80.6%) displayed diffuse and homogeneous glucose accumulation by bone marrow, with the mean SUVmax of 4.6 ± 0.6 (range, 2.8-7.0). And 20 cases (64.5%) patients showed lymphadenopathy with abnormal FDG uptake, with the range of SUVmax from 2.6 to 13.9. In addition, 7 patients (22.6%) were found the effusion without FDG uptake, 1 case showed abnormal FDG uptake by the skin, and 1 case showed elevated FDG activity in the right shoulder joint. Moreover, no abnormally elevated FDG uptake in liver and large vessels was noted in this study.

Conclusions Because of non-specific imaging features on ¹⁸F-FDG PET/CT examinations, ¹⁸F-FDG PET/CT scans could not be directly helpful in diagnosing AOSD. However, for AOSD, ¹⁸F-FDG PET/CT plays important roles in evaluating the involved extent, and guiding the biopsy of the lymph nodes, bone marrow or other tissues, which is helpful for the next clinical management.