Doppler ultrasound measurements of knee joint synovitis in rheumatoid arthritis patients treated with infliximab

Doppler ultrasound measurements were done for the thickness of synovial effusion and synovial proliferation (pannus), and diameter of the flow signals using digital calipers as well as flow signal grades and vascular resistance in the knee joint synovitis of patients with rheumatoid arthritis (RA) treated with infliximab. Forty knee joints of 20 RA patients were assessed before and after three injections of infliximab. The flow signals in the pannus were classified into the superficial and the deep signals and the joints were classified into the superficial signal pattern and the deep signal pattern. After treatment, the number of joints with superficial signal pattern reduced from 23 to 11, whereas the number of joints with deep signal pattern increased from 17 to 29 (P=0.0066), with a significant reduction of the superficial signal grades (P=0.0003). The mean cortical (posterior) pannus thickness increased significantly in the joints with superficial signal pattern (P=0.022) and in the total joints (superficial plus deep signal pattern) (P=0.031) but not in the joints with deep signal pattern. After 6 weeks of treatment with infliximab, the hyperemia in the superficial layer of the pannus developed into proliferation of the cortical pannus in the knee joints.