The use of MRI in the evaluation of myopathy.

MRI has revolutionized the practice of many branches of medicine. However, within the field of Neurology MRI is used almost exclusively to examine the structure of portions of the central nervous system. Despite a limited number of objective tests, MRI remains an underutilized tool in the examination of the peripheral nervous system. This review will briefly discuss the limitations of current testing, and then summarize how the physics of MRI helps predict normal and abnormal findings in disease affecting skeletal muscle. The cardinal radiologic abnormalities affecting muscle (atrophy, hypertrophy, pseudohypertrophy, mass, and altered signal intensity) are reviewed. Special attention is given to how MRI can be utilized during the evaluation of such disorders. Finally, the roles of MRI as a prognostic tool and as a potential endpoint in long-term management of myopathy are evaluated.