[Technique and value of arthrosonography in rheumatologic diagnosis. 1: Ultrasound diagnosis of the knee joint]

Within the last few years, ultrasonography (US) of joints has attained a firm position for the diagnosis of joint diseases. Degenerative as well as inflammatory changes can be recognized using this method. With new, higher resolution techniques even bone surfaces and tendon textures can be visualized in greater detail. The advantages of sonography are general availability and low costs. When used properly, as a non-invasive procedure US has no detrimental effects on patients. The disadvantages of this technique result from its physical limitations, such as high reflection of US on bone and the negative correlation between resolution and penetration which makes US imaging difficult in deeper regions. The current technical development of probes and imaging processing, however, promises better deep structure imaging in the future. The quality of ultrasound examination always depends on the technical equipment, as well as on the patients' individual tissue constitution and the experience of the physician. It is possible to avoid misinterpretation and to increase the diagnostic value of US by using a standardized technique and professional knowledge of the specific aspects of the method. The significance of qualified education and sufficient training of sonographers is to be stressed. The aim of this article is to deliver a basic contribution to the standardization and quality assurance of joint US and to indicate the value of this method. In addition to the overview the authors propose guidelines for performance and interpretation of joint US. Due to the major significance of the knee joint in rheumatology it was decided to begin the work in this area.