Imaging of the hip in patients with rheumatic disorders.

Hip joint abnormalities are commonly encountered in patients with rheumatic disorders. Although conventional radiography remains the mainstay for diagnosis of joint damage and subsequent follow-up, magnetic resonance imaging and, to a lesser extent, ultrasound have afforded the ability to detect early signs of articular involvement (i.e., synovitis and bone erosions), and to assess disease activity in treated patients. In more advanced stages of rheumatic disorders, magnetic resonance imaging and ultrasound are both useful in assessing paraarticular involvement (i.e., bursitis and synovial cysts).