Imaging of talar dome chondral and osteochondral lesions.

Talar dome chondral and osteochondral lesions are a common cause of ankle pain and subjective instability. The goal of imaging these lesions is primarily their detection, demonstration of their position and extent, including status of the chondral surface, demonstration of any associated chondral delamination, assessment of the integrity of the subchondral plate, and assessment of the cancellous subchondral bone for bone marrow edema like signal, sclerosis, cystic change, and for the presence of an unstable osteochondral fragment. Although plain radiography, computerized tomography, and bone scan may be helpful in the detection and characterization of these lesions, magnetic resonance imaging is the only imaging modality that will provide a comprehensive assessment of all these issues. Technical aspects of plain radiography, computerized tomography, and magnetic resonance imaging are discussed, and imaging findings are presented.