To explore the application value of super micro-vascular imaging in the evaluation of patients with rheumatoid arthritis (RA) synovial pannus.

Totally 48 rheumatoid arthritis patients treated in Department of Rheumatology, Capital Medical University Affiliate Beijing Chaoyang Hospital from December, 2014 to May, 2015 were included. Japan's Toshiba Aploi500 color Doppler ultrasound diagnostic apparatus was applied to exam the bilateral wrist joint and 1-5 metacarpophalangeal joints of both hands of 48 RA patients after hospitalized. The thicknesses of the synovial joints were recorded. It was also recorded that if there was hydrops in the articular cavity. The change of tendons around joints, PDI and SMI blood flow signals in the thickening of the synovial membrane were also recorded. Meanwhile, the PDI and SMI blood flow signals in the thickening of the synovial membrane were graded to analyze the clinical DAS28 scores and relative laboratory examination indexes.

Within 576 joints of 48 patients, 82 synovial membranes of wrist joints and 78 of metacarpophalangeal joints thickened. The proportion of blood flow signals detected by SMI in thickened synovial membranes of wrist joints was 81%, while that of PDI was 59%. The proportion of blood flow signals detected by SMI in thickened synovial membranes of metacarpophalangeal joints was 87%, while PDI was 64%. The differences of blood flow signals rate of thickened synovial membranes between both wrist joints and metacarpophalangeal joints were statistically significant, so as the comparison of two imaging patterns (χ²=9.542, 0.002, χ²=11.272, 0.001, all P<0.01). The differences of the grading of PDI and SMI blood flow signals in the thickening of the synovial membranes between wrist joints and metacarpophalangeal joints were statistically significant (Z=-3.835, 0.001, both P<0.01; Z=-3.611, 0.001, both P<0.01). DAS28 scores and SMI blood flow signals grading were positively related (r=0.82, P<0.05).

SMI imaging provides better evaluation in thickened synovial pannus of RA patients. Meanwhile, SMI shows better correlation with RA activity degrees and can provide auxiliary diagnosis in the disease activity and severity.