GNE and Becker muscular dystrophy: As a non-invasive quantitative MRI technique, T1-mapping has been increasingly applied to monitor chronic fatty degenerations of lower limb muscles within the course of NMDs; e.g. Becker muscular dystrophy (BMD) or UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) myopathy [16–18].