18F-FDG PET/CT Associates With Disease Activity and Clinical Recurrence of AOSD Patients.

Objective

The purpose of this study was to explore the value of 18F-FDG PET/CT in monitoring the disease activity and predicting the prognosis of the Adult-onset Still's disease (AOSD).

Methods

We retrospectively analyzed the electronic medical records of 45 AOSD patients who underwent 18F-FDG PET/CT in the Second Xiangya Hospital. PET/CT imaging and clinical information were retrospectively reviewed and analyzed. 18F-FDG uptake was assessed by measuring standard uptake value (SUV) in the spleen, liver, bone marrow, and lymph nodes. The spleen-to-liver ratio of the SUVmax (SLRmax) and SUVmean (SLRmean), the bone-to-liver ratio of the SUVmax (BLRmax), and SUVmean (BLRmean), and the lymph nodes-to-liver ratio of the SUVmax (LyLRmax) were calculated. Clinical and laboratory information were collected and evaluated for association with metabolic parameters of 18F-FDG PET/CT. The influencing factors for recurrence within 1 year were analyzed to determine whether 18F-FDG PET/CT can predict the prognosis of AOSD patients.

Results

Elevated 18F-FDG uptake could be observed in bone marrow, spleen, and lymph nodes of AOSD patients. Correlation analysis between 18F-FDG uptake of organs and laboratory examinations showed that SLRmean positively correlated with LDH, AST, ferritin, and the systemic score (r = 0.572, 0.353, 0.586, and 0.424, P < 0.05). The SLRmean had the highest correlation with ferritin (r = 0586, P < 0.001). All metabolic parameters in spleen, including SUVmax, SUVmean, SLRmax, and SLRmean, are positively correlated with LDH level (r = 0.405, 0.539, 0.481, and 0.572, P < 0.05). Bone marrow SUVmax, BLRmax, and BLRmean were correlated with C-reactive protein (CRP) level (r = 0.395, 0.437, and 0.469, P < 0.05). Analysis of the influencing factors of recurrence within 1 year showed that the spleen SUVmax, spleen SUVmean, SLRmax, SLRmean, ferritin, and the systemic score of the recurrence group was significantly higher than the non-recurrence group (P < 0.05). The SLRmean cutoff of 1.66 with a sensitivity of 72.7% and specificity of 80.0% had the highest performance in predicting recurrence.

Conclusion

The glucose metabolism of the liver, spleen, and bone marrow of AOSD patients were correlated with laboratory inflammatory indicators and system score, suggesting that 18F-FDG PET/CT could be applied to evaluate disease activity. Moreover, spleen 18F-FDG uptake may be a potential biomarker for predicting clinical prognosis of AOSD patients.