Superb Microvascular Imaging Is Better Than Power Doppler Ultrasound in Diagnosing Subclinical Synovitis in Patients With Inflammatory Arthritis in Remission.

Objective: The aim of this study was to investigate the value and reliability of superb microvascular imaging (SMI) in detecting subclinical synovial inflammation in patients with inflammatory arthritis.

Methods: All patients with inflammatory arthritis who had achieved clinical remission were retrospectively analyzed and evaluated with SMI and power Doppler ultrasound (PDUS). Subclinical synovitis was graded by a semiquantitative score (0-3) for each imaging method. Imaging findings and synovitis scores were compared between the rheumatoid arthritis (RA) group and non-RA group.

Results: Eighty RA patients with 270 joints and 38 non-RA patients with 112 joints were recruited. In all patients, the remission rates of SMI and PDUS were 73.7% and 79.7%, respectively. The remission rates by SMI were found lower and the sensitivity of SMI was higher than PDUS in both RA and non-RA groups. Compared with PDUS, the number of joint count with synovial vascular flow signals was found to be significantly higher in SMI in each group (p < 0.001). Moreover, semiquantitative ultrasound scores were found significantly higher with SMI in each joint (p < 0.001).

Conclusion: SMI appears to be better than PDUS in detecting synovial signals in terms of joint number and vascularity scoring in monitoring disease activity in patients with inflammatory arthritis in clinical remission. Future research should focus on SMI and new ultrasound-based activity scores to identify and achieve true remission.