The superb microvascular imaging is more sensitive than conventional power Doppler imaging in detection of active synovitis in patients with rheumatoid arthritis.

• SMI correlated well with PDI and was more sensitive for detection of active synovitis in RA. • The SMI-sum was not only of greater value but also more strongly correlated than the PDI-sum with clinical inflammatory indicators including ESR, CRP, and DAS28 on initial and follow-up US examinations. • The SMI-sum was even significantly increased in patients with clinical remission.