Total metabolic lesion volume of lymph nodes measured by 18F-FDG PET/CT: a new predictor of macrophage activation syndrome in adult-onset Still's disease.

Background To investigate the potential utility of quantitative parameters obtained by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in the assessment of disease severity and the occurrence of macrophage activation syndrome (MAS) in adult-onset Still's disease (AOSD). Methods Fifty-seven patients with AOSD who underwent pre-treatment 18F-FDG PET/CT were recruited in this study and compared with 60 age- and sex-matched healthy controls. Clinical features and laboratory data were recorded. The systemic score was assessed to determine the disease severity. The maximal standardized uptake value (SUVmax), metabolic lesion volume (MLV), and total lesion glycolysis (TLG) were used to evaluate the involved organs and tissues that abnormally accumulated 18F-FDG. Multivariate analysis was performed to identify the PET/CT-derived risk factors contributing to the AOSD-related MAS, and their diagnostic efficiency was evaluated. Results High 18F-FDG accumulation was observed in the bone marrow (SUVmax median, 5.10), spleen (SUVmax median, 3.70), and lymph nodes (LNs, SUVmax median, 5.55). The SUVmax of the bone marrow (rho = 0.376, p = 0.004), SUVmax of the spleen (rho = 0.450, p 62.2 (OR 27.375, p = 0.042) was an independent predictive factor for MAS with a sensitivity of 80.0% and a specificity of 93.9%. Conclusions The glucose metabolic level of the spleen could be an effective and easy-to-use imaging indicator of disease severity, and MLVtotal of LNs > 62.2 was a strong predictor of MAS occurrence in patients with AOSD.