抗TNF-α製剤使用下における関節リウマチ大関節破壊予測 : FDG-PET/CTとARASHIスコアによる検討

抄録

Objective: The Larsen grade is widely used to assess large joint destruction in patients with rheumatoid arthritis (RA). In this method, various changes might be included within a single grade. 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT) can visualize the disease activity in large joints affected by RA. The purpose of this study was to investigate the associations between the destruction of large joints in RA and FDG-PET/CT findings using a new radiographic evaluation method: the Assessment of Rheumatoid Arthritis by Scoring of large joint destruction and Healing in radiographic Imaging (ARASHI) scoring system.

Methods: Seventeen patients with RA (male, n=3; female, n=14) were enrolled in the present study. A total of 170 large joints (shoulder, elbow, hip, knee and ankle) were assessed. FDG-PET/CT was performed at the initiation of tumor necrosis factor inhibitor treatment. The extent of FDG uptake of the large joints was analyzed using the maximum standardized uptake value (SUVmax). Radiographs of the 10 large joints were obtained for each patient at baseline and after three years of treatment and were assessed according to the ARASHI score. A logistic regression analysis was performed to determine factors that predicted large joint destruction in these patients with RA.

Results: Radiographic progression of joint damage was detected in 26 joints by the Larsen grade and in 77 joints by the ARASHI score. The ARASHI status score was significantly correlated with the Larsen grade (R=0.92, P<0.001). A logistic regression analysis revealed that the ARASHI status score and the SUVmax at baseline were factors that showed the greatest association with large joint destruction at three years.

Conclusion: The ARASHI score may allow for a more detailed assessment of large joints than the Larsen method. Large joint destruction is likely to have progressed at three years in large joints with a high ARASHI status score and a high SUVmax at the initiation of biologic treatment.