Muscle magnetic resonance imaging of the lower limbs: valuable diagnostic tool in the investigation of childhood neuromuscular disorders.

ABSTRACT

Children presenting with neuromuscular symptoms are subject to exhaustive investigations. As it is noninvasive, muscle magnetic resonance imaging (MRI) is an important diagnostic tool in children, yet its impact has so far been mainly studied in small groups of genetically defined diseases, where specific MRI patterns are known. To assess the contribution of muscle MRI of the lower limbs in a diverse cohort of patients, we reviewed the diagnostic findings in 39 patients with a suspected neuromuscular disorder that underwent muscle MRI (28/39), biopsy (26/39), or both (18/39). MRI was performed without sedation in 26 of 28 patients at a mean age of 10 years (range, 1-27 years). In 10 of 28 cases (35%), MRI significantly contributed to the final diagnosis, and in 7 of 28 cases (25%), muscle MRI directly instructed genetic testing. These cases included Bethlem myopathy, laminopathy, calpainopathy, and RYR1-related myopathies. Muscle MRI serves as a valuable additional tool to guide diagnosis in suspected neuromuscular disorders in children, especially in cases with nonspecific biopsy findings.