Subtle radiographic progression at 6 months can be detected using automated quantitative software in rheumatoid arthritis while receiving tocilizumab

Objectives: We investigated whether our in-house software equipped with partial image phase-only correlation (PIPOC) can detect subtle radiographic joint space narrowing (JSN) progression at 6 months and predict JSN progression in rheumatoid arthritis (RA) patients receiving Tocilizumab. Methods: The study included 39 RA patients who were treated with Tocilizumab. Radiological progression of the finger joints was evaluated according to the Genant-modified Sharp score (GSS) at 0, 6, and 12 months. Results: The success rate of the software for joint space width (JSW) measurement was 96.8% (449/464). The 0-12-month JSW change by the software was significantly greater in joints with the 0-6-month PIPOC (+) group than the 0-6-month PIPOC (-) group (P < 0.001). The 0-12-month JSW change by the software was 0-12 month GSS (+) than with 0-12 month GSS (-) (P = 0.02). Here, '(+)' indicates the JSN progression during the follow-up period. Linear regression tests showed significant correlations between the 0-6 month and the 0-12 month PIPOC in the left second and third metacarpophalangeal joints (R2 = 0.554 and 0.420, respectively). Conclusions: Our in-house software equipped with PIPOC could predict subsequent JSN progression with only short-term observations.