Usefulness of Joint Ultrasonography in Medical Care for Rheumatoid Arthritis

Abstract

Ultrasonography (US) using a high frequency probe has recently gained attention as a useful diagnostic imaging tool in the routine medical care of musculoskeletal diseases including rheumatoid arthritis (RA) because it allows detailed real-time observation of soft tissues in shallow layers including the synovium, tendons, muscles, blood vessels, and nerves. Using a gray scale, US plots synovial thickening and synovial fluid retention in joint capsules and tendon sheaths, and then shows blood flow signals using the Doppler method. This allows diagnosis of active synovitis, arthritis, and tenosynovitis depending on whether the observed Doppler signal appears as an accumulation of spotty signals in line with the site of synovial thickening. US is useful for the early diagnosis, determination of activity and remission, and prediction of prognosis of arthritis because of its higher sensitivity to detect inflammation in an articular site compared with that of conventional and blood examinations. Because performing routine joint US for an articular site in every patient is difficult due to temporal restriction, it is practical to perform joint US only in selected cases and when conventional examinations fail to detect inflammation around the articular sites. Therapeutic agents for RA have significantly advanced in recent years. Improvements in the diagnostic techniques for RA are also needed. Joint US is a useful diagnostic imaging tool that promises better medical care through complementation of judgment based on conventional examination.