MR imaging of the knee: current concepts

Magnetic resonance imaging (MRI) has revolutionized the evaluation of musculoskeletal soft tissue disorders. This is most evident in the evaluation of internal derangements of the knee. MRI is an accurate and cost-effective means of evaluating a wide spectrum of knee injuries, ranging from cruciate-collateral ligament injuries to cartilage deficiencies. For clinicians and radiologists, evaluation of an injured knee using MRI requires knowledge of the proper imaging techniques, normal anatomy and most common variants, and the clinical significance of detected abnormalities. Advances in magnetic field strength, gradient strength, and coil design have facilitated the development of new pulse sequences, which have partly transformed knee MRI from routine morphologic imaging to molecular imaging. This article will review current MRI concepts of meniscal and cruciate ligament tears, as well as new developments in MRI of the knee such as 3-T imaging and techniques for meniscus and cartilage imaging.