Comparative Analysis of Contrast-Enhanced Ultrasound and Superb Microvascular Imaging in Rheumatoid Arthritis: Initial Findings of Second-Line Biologic-Resistant Patients.

OBJECTIVE: Detection of synovitis is essential for assessing rheumatoid arthritis (RA) activity and changing the therapy. This study aims to explore the level of agreement and correlation between Disease Activity Score 28 calculated with C-reactive protein levels (DAS28-CRP) and contrast-enhanced ultrasound (CEUS) and Superb microvascular imaging (SMI) in the classification of disease severity index in patients with RA who did not respond to second-line biologic therapy. METHODS: SMI and CEUS were applied to 37 patients with active RA does not respond to second-line biologic therapy. We evaluate the radiocarpal joint of both wrists. Differences in positive synovial vascularity (SV) and its semi-quantitative scale were observed, and the correlations of SMI and CEUS results with DAS-28. To obtain robust estimates and accurate confidence intervals, we conducted all analyses using nonparametric bootstrap methods. RESULTS: The results indicate that CEUS method shows fair agreement with DAS 28 clinical method (Kappa = 0.38), 95% CI (0.172, 0.547), p = 0.006, while SMI has weaker agreement (Kappa = 0.13) 95% CI (0.027, 0.246), p = 0.039. The correlation between CEUS and SMI is strong (ρ = 0.82), CI 95% (0.705, 0.879), suggesting that the two imaging modalities tend to produce similar classifications, although CEUS showed a stronger association with DAS28-CRP. CONCLUSION: Use of CEUS to detect vessels in the synovium and visualization of local SV is the method that most correlates with disease severity in relation to DAS 28 in patients with synovial arthritis who do not respond to second-line biologic therapy compared with SMI.