MYO-MRI diagnostic protocols in genetic myopathies

•Whole body MRI (WBMRI) is an important imaging biomarker for myopathies.•Different mutations within the same gene can have different clinical WBMRI patterns.•WBMRI assesses all muscles in face, limbs and trunk not imaged in standard protocols.•MRI sequences measure atrophy / fatty infiltration (T1) and edema (T2 or STIR, IDEAL T2).•3-point Dixon sequences provide better quantification of muscle water and fat content. Whole-body magnetic resonance imaging has emerged as a useful imaging tool in diagnosing and characterizing the progression of myopathies and muscular dystrophies. Whole-body MRI indications and diagnostic efficacy are becoming better defined with the increasing number of cases, publications and discussions within multidisciplinary working groups. Advanced Whole-body MRI protocols are rapid, lower cost, and well-tolerated by patients. Accurate interpretation of muscle Whole-body MRI requires a detailed knowledge of muscle anatomy and differential pattern of involvement in muscle diseases. With the surge in recently identified novel genetic myopathies, Whole-body MRI will become increasingly useful for phenotypic validation of genetic variants of unknown significance. In addition, Whole-body MRI will be progressively used as a biomarker for disease progression and quantify response to therapy with the emergence of novel disease modifying treatments. This review outlines Whole-body MRI indications and updates refined protocols and provides a comprehensive overview of the diagnostic utility and suggested methodology of Whole-body MRI for pediatric and adult patients with muscle diseases.