Assessment of synovitis in the knee of patients with newly-diagnosed rheumatoid arthritis using high frequency and color Doppler ultrasonography

Abstract

To investigate the value of high frequency and color Doppler ultrasonography in detection of synovitis and the intra-articular vascularization in the knee joint of patients with newly-diagnosed rheumatoid arthritis (RA). Forty-one patients (30 women, 11 men) with newly-diagnosed RA were recruited to a cross sectional study (RA group). Forty-one age and gender-matched healthy volunteers were used as control group. The thickness of hydatid fluid, synovium hyperplasia, color flow imaging, peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI), venous blood flow and intra-articular perfusion were evaluated by high frequency and color Doppler ultrasonography. Totally 91.46% knee joints with synovial hyperplasia (> 2 mm) were found in 41 patients with RA (75/82 knee joints), and the thickness of the synovial membrane was 2.2 - 19.7 mm (average 6.3 ± 3.4 mm). In aspect of blood flow, the percentage of 0 to 3 grade were 18.67% (14/75), 29.33% (22/75), 45.33% (34/75) and 6.67% (5/75), respectively; the results of arterial blood were indicated with PSV (10.82 ± 3.71 cm/s), EDV (3.86 ± 1.12 cm/s) and RI (0.61 ± 0.07), while the average of venous blood velocity was 2.72 ± 1.02 cm/s. Joint effusion was found in 69 joints (84.15%) with the anteroposterior diameter 2.4 - 16.1 mm (average 6.9 ± 3.2 mm). The thickness of synovial membrane was 1.2 - 1.8 mm (average 1.4 ± 0.4 mm) and no significant difference were observed in joint effusion, signal of blood flow and thickness of synovial membrane in the control group. High frequency and power Doppler ultrasonography may be a valuable and optimal clinical tool to accurately and objectively detect synovial hyperplasia, vascular pannus formation and joint effusion in the knee joint of patients with RA.