Evaluation of finger joint synovial vascularity in patients with rheumatoid arthritis using contrast-enhanced ultrasound with water immersion and a stabilized probe.

PURPOSE.: To assess synovial microvascularity in finger joints with rheumatoid arthritis (RA) by contrast-enhanced ultrasound (CEUS), distinguishing between cases of active disease and those in remission; to standardize the technique for software analysis. METHODS.: Fifty-two finger joints of RA patients (26 with active disease and 26 in remission) were immersed in water and examined by CEUS using a fixed probe. Signal intensity curves were calculated with the software. RESULTS.: Contrast enhancement was detectable in all 26 patients with active RA (100%), but not in 25 of 26 patients in remission (96%); one of the latter patients (4%) showed minimal enhancement. The method's sensitivity and specificity in distinguishing active disease from remission were 100% and 96%. The grades of synovial enhancement correlated with clinical disease activity and software flow parameters. The peak contrast levels correlated with clinical activity, a peak of 9% representing the cutoff between remission and active disease. CONCLUSIONS.: CEUS with a fixed probe on finger joints immersed in water detected synovial vascularization in RA, producing results suitable for standardized software analysis and avoiding artifacts.