Assessment of disease activity of rheumatoid arthritis by ultrasonography

Abstract Rheumatoid arthritis (RA) is a typical autoimmune disease of connective tissue, with the synovial joints as the main site of the disease. Bone erosion occurs in the initial stage. A key factor in treating and understanding the prognosis of the disease is to determine which stage of the lesion is caused by rheumatoid arthritis. In order to assess bone erosion and determine the degree of synovial proliferation, ultrasonography has come into the spotlight as a method of visualizing the rheumatoid arthritis lesion, which cannot be distinguished superficially from the cutaneous condition. Joint ultrasonography is a relatively inexpensive procedure that can be used to examine patients repeatedly; therefore, we can compare serial data from such patients. The joint lesion, which we focused on, can be understood in real time and is superior in many respects. However, at present, there are problems with examiner bias and the lack of a standard assessment method, because joint ultrasonography alone does not provide objective imaging findings. Now, joint ultrasonography is also useful as a supportive method to clarify mobility around the articular region. Ultrasonography might be used as a supportive method for the early diagnosis, assessment of disease activity, evaluation of the drug efficacy, prognosis, and as part of the differential diagnosis.