Whole body muscle MRI protocol: Pattern recognition in early onset NM disorders

Abstract A paediatric and adult whole-body MRI (WB-MRI) protocol using a 1.5-T MRI system was used to examine 117 individuals (106 patients, 11 asymptomatic relatives). Genetic diagnosis was obtained in 38 subjects ( RYR1 , LMNA , COL6 , DNM2 , GAA , TPM2 , SGCA , MYH7 , NEB , SMN , FKBP14 ). T1-TSE WB-MRI sequences were abnormal in 67% of patients and 27% of asymptomatic relatives. Multiple striped signal abnormalities (‘tiger-like’) were very specific for COLVI-related myopathy. Distinct involvement of muscles in the head, neck, trunk, girdles and limbs was observed in patients with RYR1 , SEPN1 , GAA , LMNA or TPM2 mutations. Abnormalities and pattern recognition were more frequent in patients studied due to rigid spine syndrome (80% abnormal, recognisable in 75% of cases), hyperlaxity syndrome (75%; 50%) or with confirmed myopathy but absence of these markers (71%; 40%). Pattern was consistent with the molecular diagnosis in 97%. Mild clinical involvement was revealed by muscle testing in three parents with abnormal WB-MRI. The Garches WB-MRI protocol is suitable for a large spectrum of adults and children with early-onset neuromuscular disorders and can be used as an effective screening test in relatives. Recognition of characteristic patterns of abnormalities is improved by whole-body scanning compared with sequential MRI and, therefore, diagnostic impact is greater.