F-18 FDG uptake patterns and disease activity of collagen vascular diseases-associated arthritis.

PURPOSE: The purpose of the present study was to investigate F-18 FDG uptake patterns, and to see whether joint F-18 FDG uptake reflected disease activity in patients with collagen vascular diseases (CVD)-associated arthritis. MATERIALS AND METHODS: A total of 72 patients with CVD-associated arthritis and 30 control subjects who underwent F-18 FDG PET or PET/CT were retrospectively investigated. PET images of 12 major joints, 7 minor joints, and extra-articular accumulation were assessed. We investigated F-18 FDG uptake patterns and the relationships between the degree of F-18 FDG uptake and distribution, clinical symptoms, and laboratory test results. RESULTS: Remitting seronegative symmetric synovitis with pitting edema syndrome, mixed connective tissue disease, rheumatoid arthritis, and systemic sclerosis tended to show strong and multiple joint F-18 FDG uptake. F-18 FDG uptake was found in bone marrow (86%) and/or spleen (57%) in 7 patients with adult-onset Still disease. The maximum standardized uptake value (SUVmax) correlated with the counts of erythrocyte sedimentation rate, matrix metalloproteinase-3, IgG, and IgA. Joint swelling had a positive association with SUVmax. Multiple logistic regression analyses revealed that factor associated with increased SUVmax of the joint was joint swelling (P = 0.005). CONCLUSIONS: The degree of joint F-18 FDG uptake may contribute to predict active inflammatory process of the joint. In addition, F-18 FDG uptake patterns may have a potential which helps differential diagnosis of CVD-associated arthritis.