“…A number of studies have shown that ultrasound detects synovial inflammation more sensitively than does clinical joint examination [2][3][4][5] and ultrasound-detected synovitis correlates well with magnetic resonance imaging (MRI) [4,[6][7][8] and histopathological findings [9,10]. As synovial inflammation is the most characteristic pathophysiology of rheumatoid arthritis (RA), sonographic assessment of synovial inflammation has been shown to improve the accuracy of diagnosis [11][12][13][14][15][16], optimize the assessment of disease activity [15,[17][18][19][20][21][22], predict relapse after discontinuation of biological treatment [23], and also improve the physicians' joint examination skill [24] in the management of RA. Therefore, a rapidly increasing number of rheumatologists now use ultrasound for the assessment of synovial inflammation in daily practice, training, and education [25].…”