MR imaging appearance of rheumatoid arthritis in the foot.

Although conventional radiographs remain the initial mainstay for imaging of the foot in patients with rheumatoid arthritis (RA), magnetic resonance (MR) imaging has afforded the ability to detect early signs of the disease (i.e., synovitis, tenosynovitis, bone lesions, and bursitis), especially at the forefoot. In addition, the relatively symmetric distribution of the imaging abnormalities depicted in the metatarsophalangeal joints and the frequent involvement of the retro-calcaneal bursitis are almost specific for RA. In more advanced stages of the disease, MR imaging is well suited to evaluation of the hindfoot joints and tendons as well as the musculoskeletal complications of RA (e.g., tendon disruption, rheumatoid nodules, sinus tarsi syndrome).