Conventional and ultrashort time-to-echo magnetic resonance imaging of articular cartilage, meniscus, and intervertebral disk.

Magnetic resonance imaging (MRI) examination of musculoskeletal tissues is being performed routinely for diagnoses of injury and diseases. Although conventional MRI using spin echo sequences has been effective, a number of important musculoskeletal soft tissues remain "magnetic resonance-invisible" because of their intrinsically short T2 values resulting in a rapid signal decay. This makes visualization and quantitative characterization difficult. With the advent and refinement of ultrashort time-to-echo (UTE) MRI techniques, it is now possible to directly visualize and quantitatively characterize these tissues. This review explores the anatomy, conventional MRI, and UTE MRI of articular cartilage, meniscus of the knee, and intervertebral disks and provides a survey of magnetic resonance studies used to better understand tissue structure, composition, and function, as well as subtle changes in diseases.