Background Larsen method has been widely used to assess large joint destruction in patients with rheumatoid arthritis (RA). In that method, various changes might be included within one grade. 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT) can visualize the disease activity in large joints affected by RA.

Objectives The associations between destruction of the large joint and FDG-PET/CT findings were investigated using a new radiographic evaluation method “ARASHI Scoring system”¹.

Methods A total of 260 large joints (shoulder, elbow, hip, knee and ankle) in 26 RA patients (six males and 20 females; mean age of 66.9 years) were assessed in this study. FDG-PET/CT was performed at baseline and six months after the initiation of biological therapy. The extent of FDG uptake in large joints was analyzed using the maximum standardized uptake value (SUVmax). Radiographs of the 10 large joints per patient obtained at baseline and after three years were evaluated according to the ARASHI change score. A multiple regression analysis was performed to determine the factors most significantly contributing to the progression of large joint destruction within three years.

Results Eighteen joints had previously been treated with joint replacement surgery at baseline and nine joints were treated with joint replacement surgery in three years. They were excluded from this study, so we evaluated 233 large joints. The ARASHI status score (score at baseline), SUVmax at baseline, DAS28-ESR and ΔSUV (SUVmax at baseline – SUVmax at six months) were significantly associated with high level changes of ARASHI change score. A multiple regression analysis revealed ΔSUV was found to be the most associated factor with joint destruction at three years (p<0.05).

Conclusions We investigated large joint destruction in RA patients using FDG-PET/CT and ARASHI scoring method. This study suggested the importance to decrease SUV value in RA patients with high level of SUVmax at baseline for the prevention of large joint destruction.

1. Kaneko A, Matsushita I, Kanbe K, Arai K, Kuga Y, Abe A, Matsumoto T, Nakagawa N, Nishida K. Development and validation of a new radiographic scoring system to evaluate bone and cartilage destruction and healing of large joints with rheumatoid arthritis: ARASHI (Assessment of rheumatoid arthritis by scoring of large joint destruction and healing in radiographic imaging) study. Mod Rheumatol. 2013 Nov;23(6):1053–62.

Disclosure of Interest None declared