MR imaging of ankylosing spondylitis

Abstract

Ankylosing spondylitis (AS) is one of a group of disorders characterized by association with HLA-B27 histocompatibility complex, seronegativity for rheumatoid factor, and propensity for inflammation at entheses, synovial articulations, and cartilaginous articulations. The radiographic hallmark of the disease is ankylosis, and the principle sites of involvement are the sacroiliac joints and spine, with less frequent involvement of other joints, including the pubic symphysis, hips, shoulders, knees, hands, feet, and sternoclavicular, acromioclavicular, sternomanubrial, and temporomandibular joints. Following a brief discussion of the basic pathophysiology and typical clinical findings of AS, we describe the typical magnetic resonance imaging features of the disease as it is manifests in the axial skeleton. Finally, a brief mention of special considerations in the radiographic evaluation of the AS patient in the setting of trauma is made.