Doppler sonography in rheumatology.

The importance of ultrasonography in rheumatology has increased dramatically within the last few years both with regard to clinical practice and to research. High-resolution colour Doppler ultrasound equipment is, to date, widely available. Colour and power Doppler studies of intra-articular and peritendinous blood flow allow an estimation of the inflammatory activity and aid in distinguishing anatomical structures. Contrast agent increases the ability of ultrasonography to detect even minor perfusion. These findings have a practical clinical impact on the management of inflammatory rheumatic diseases. The resolution of ultrasonography is superior to that of magnetic resonance imaging (MRI) and computed tomography (CT) with regard to superficial anatomical structures. Furthermore, ultrasonography can depict the artery wall in contrast to angiography. In temporal arteritis and Takayasu's arteritis, ultrasonography depicts characteristic, homogenous wall thickening, stenoses and acute occlusions. These pathologies resolve quickly with treatment in the temporal arteries and much more slowly in larger arteries.