[Evaluation of rheumatoid arthritis of the knee with Doppler color]

Color-Doppler US was used to study the vascularization of the synovial membrane and of the periarticular tissues of the knee in 14 normal subjects and 15 patients with active rheumatoid arthritis. The normal subjects exhibited few spot signals within the connectival spaces surrounding the knee and adjacent to the femoral condyles and to the tibial plates. The signals were mostly arterial and impedance was high because of the absence of inversion of diastole. A hypervascular pattern was detected in 13/15 patients with rheumatoid arthritis as a result of hyperemia associated with inflammation and synovial neoangiogenesis. In these patients, the signals came mostly from the synovial pannus and the soft tissues surrounding the joint. Spectral analysis detected both venous and arterial waveforms with lower resistance than normal (resistive index ranging 0.65 to 0.76). After local treatment, both venous and low-impedance arterial signals were no longer detectable in 4/9 patients with clinical remission. In conclusion, color-Doppler US can support gray-scale US in the assessment of joint inflammation in rheumatoid arthritis patients. Vascular findings seem to correlate well with local symptoms. Color-Doppler US could make a useful tool for monitoring the clinical activity of the disease in selected joints.