MR imaging of the tendons of the foot and ankle.

Hindfoot pain from tendon pathology is common and seen in a wide range of patients from young athletes to older sedentary individuals. Magnetic resonance (MR) is an excellent technique for imaging tendons and for identifying injuries that can be treated with surgery. MR also demonstrates the presence of bone marrow edema, which is a cause of pain and often a marker for adjacent tendon injury. Finally, MR can reveal other etiologies that cause similar hindfoot pain, such as osteochondral injuries and impingement. In this article, we review the normal MR appearance of the ankle tendons and tendon sheath fluid. MR protocols for imaging the various ankle tendon groups are presented. We discuss the MR appearance of tendon pathology, including tendonosis/ tendinopathy, tenosynovitis and peritendonosis, partial and complete tears, subluxation and dislocation, and entrapment. The Achilles, medial, lateral, and anterior tendon groups are discussed separately so as to focus on the MR appearance specific to each region of the ankle.