Because of the good contrast obtained in soft tissues, ultrasound permits differentiation of the exudative and proliferative synovial tissue changes, as well as tenosynovitis. Superficial cartilage and bone lesions or erosions can be detected through ultrasound earlier than with conventional radiodiagnostics. The use of power Doppler sonography with ultrasound contrast agents is especially helpful in the further differentiation of the synovial inflammatory process and hence, progression of the destructive processes in the joint can be more clearly evaluated. Arthrosonography aids in the diagnosis of early arthritis, particularly in patients without pathological radiological findings and suspicious clinical results. Moreover, it permits sound assessment of the disease progression and hence, therapeutic monitoring. The method is patient friendly, has high diagnostic value and is an integral component in the clarification of arthritic symptoms.