Colour Doppler ultrasonography to detect pannus in knee joint synovitis.

OBJECTIVE To determine if colour Doppler ultrasonography can characterise the nature of intraarticular echogenic structures and synovial villi more precisely than conventional ultrasonography. METHODS This is a prospective study on 20 patients--10 with rheumatoid arthritis and 10 with osteoarthritis. Colour Doppler ultrasonography of the knee joints was performed prior to total prosthetic replacement. Two independent, trained physician ultrasonographers examined the knee to be replaced with different ultrasound equipment using colour Doppler and power Doppler ultrasonography. The existence and extent of pannus were then assessed surgically and histologically. RESULTS All 9 patients with histologically detected pannus had perfused, echogenic, intraarticular structures (ultrasonographer 2; ultrasonographer 1: 8 out of 9 patients). Sparse perfusion was detected in 1 patient (investigator 1) and in 5 patients (investigator 2) with extensive non-destructive synovial proliferation. Colour Doppler and power Doppler ultrasonography were equivalent in detecting small intraarticular vessels. CONCLUSION Colour Doppler ultrasonography improves the differentiation of intraarticular structures compared to conventional ultrasonography.