Abstract:

Objective: To investigate the display of small synovial vessels in patients with rheumatoid arthritis (RA) at the clinical remission stage by ultrasonic micro flow imaging superb mircovascular imaging (SMI). Methods: Forty-two RA patients at the remission stage were examined by SMI to observe the display of synovial blood flow and synovial blood flow classification. Contrast enhanced ultrasound (CEUS) blood flow pattern was served as a control and the differences in results between the SMI and CEUS were compared. The correlation of SMI or CEUS with CRP and ESR were analyzed. Value of SMI to find subclinical synovitis in RA patients at the clinical remission stage were evaluated. Results: Among the RA patients at clinical remission stage, the detection rate of synovial blood flow by SMI and CEUS (those with blood flow grade above 1) were 73.8% and 83.3%, respectively. There was no significant difference in the detection of synovial blood flow between the two groups (P=0.160). There is a strong consistency between them (Kappa=0.723, P<0.001). There was also no significant difference in blood flow classification between the two methods (P=0.083), there is a moderate consistency between the two methods (Kappa=0.654, P<0.001). The numbers of synovial blood flow found by SMI or CEUS after further intensive treatment were significantly lower than that before intensive treatment (P<0.001). There was no significant correlation between the semi quantitative score of blood flow of subclinical synovitis assessed by CEUS or SMI and the inflammatory factors of CRP and ESR. Conclusions: SMI can sensitively detect the microvessels in the syno-vium, esspescial for those local inflammation without increase of ESR or CRP. The evaluation efficiency is consistent with that of contrast-enhanced ultrasound, which is a simple method that can be used to detect the disease in remission stage.

Key words: Rheumatoid arthritis, Clinical remission stage, Contrast enhanced ultrasound, Superb mircovascular imaging, Synovial blood flow