MRI of the ankle and hindfoot.

MRI of the ankle and hindfoot has become a widely used diagnostic test. The major indications for MRI of this region are disorders of tendons and bones. Avascular necrosis is common in the foot, usually seen after talus fractures or spontaneously in the metatarsal heads. Other causes of a marrow edema pattern include occult fractures, arthritic disorders, reactions to altered biomechanics, osteomyelitis, and regional migratory osteoporosis. The most frequently diseased tendons in the ankle are the Achilles, posterior tibial, and peroneal. MRI can be used to diagnose most disorders of these tendons, as well as stage these disorders to allow appropriate therapy. Most of these tendon disorders follow a recognized sequence of progression using the Achilles tendon as a model.