Weight-bearing MR Imaging of Knee, Ankle and Foot.

Clinical management of several pathologies of the lower extremity joint relies on instrumental imaging evaluation. The assessment of joint changes with physiologic load requires studies using positions with the patient standing. Weight-bearing radiographs are the mainstay for the evaluation of several conditions such as knee osteoarthritis, pes planus, and hallux valgus, in particular to obtain measurements of articular parameters, especially for presurgical studies. In the last few years, dedicated magnetic resonance imaging and computed tomography scanners have also been developed to obtain high-resolution, multiplanar, and sectional images of the lower extremity joints during weight-bearing. These techniques provide detailed information on joint structure modifications under load in both physiologic and pathologic conditions to improve the diagnostic accuracy of weight-bearing studies.