Novel contrast mechanisms at high field 1

This article reviews the technical principles of novel contrast mechanisms for musculoskeletal imaging. Ultrashort echo-time imaging allows the visualization of fast T2 relaxing tissue components that are not directly detectable by standard magnetic resonance imaging. This offers several new applications, especially in musculoskeletal imaging, to visualize these tissue components directly. Magnetization transfer techniques, which have been successfully applied to assess demyelinization processes in white brain matter, for example, can be used to detect the integrity of the collagen network of cartilage, and they may help for the detection of early cartilage degradations. Finally, diffusion-weighted imaging represents a further technique to detect bone marrow pathologies or indicate collagen degradation and water content in cartilage. The technical details and implementation techniques of these dedicated imaging modalities are demonstrated and reviewed in this article, and some clinical examples are presented.