Imaging Skeletal Muscle by Magnetic Resonance Imaging (MRI)

Skeletal muscle comprises a significant proportion of whole-body mass, and its maintenance is critical to the quality of life, particularly with aging. It is therefore important to determine changes in skeletal muscle mass and quality, accurately and reliably. Magnetic resonance imaging (MRI) is a commonly used noninvasive imaging method to quantify whole-body skeletal muscle mass, but it can also be used to examine muscle quality. In this chapter we outline the main materials and methods required to determine skeletal muscle mass using MRI. We initially provide a brief overview of the underlying principles of MRI before moving on to key methodological considerations in determining skeletal muscle volume, muscle to fat ratio and the tracking of individual skeletal muscle fibers. We will finally describe approaches to automatic segmentation and processing before finishing with some future considerations and potential directions.