[The usefulness of ultrasonography in synovial disease].

Synovial disease is common in clinical practice and can have different causes. The development of high resolution ultrasonography (US) has led to greater use of US in the study of synovial disease. In this context, US is useful because (1) it can detect not only synovial disease, but also its consequences as tissue damage (erosions); (2) it can guide arthrocentesis when clinical attempts to obtain joint fluid have been unsuccessful, especially in joints that are difficult to access (hips), or sometimes when joint infections are clinically suspected; (3) it enables the efficacy of treatment for synovitis to be evaluated; and (4) it makes it possible to distinguish benign cystic lesions from other tumors. The overall evaluation of synovial disease is based on semiologic criteria that enables these alterations to be classified into four main groups: (a) joint effusion, (b) cystic synovial lesions, (c) intra-articular free bodies, and (d) synovial thickening.