MAGNETIC-RESONANCE-IMAGING OF MUSCLES IN MYOTONIC-DYSTROPHY

The MR findings in 27 patients with myotonic dystrophy were compared w ith those observed in 11 patients with other muscular dystrophies: six with limb-girdle dystrophy, three with facioscapulohumeral muscular d ystrophy and two with Becker-type muscular dystrophy. Clinical status was graded into 10 stages. The MR study was performed at the medium th ird of the thigh, with a slice thickness of 7.5 mm (TR: 750/TE: 25 for T-1; TR: 2200/TE: 30/90 for DP/T-2). Muscle signal intensity was eval uated with a four-point grading scale using subcutaneous fat as a refe rence. Statistical analysis was done using the Mann-Whitney-Wilcoxon's test and simple linear regression. In the myotonic dystrophy group, 8 1.4% of the patients showed an abnormal signal at the crural muscle le vel, adopting a semilunar shape around the anteroexternal side of the femur. The presence and intensity of this hyperintense signal correlat ed positively with the duration of disease (r=0.54) and the clinical s tage (r=0.69). Of the 11 patients with other muscular dystrophies, onl y three (27.2%) showed hyperintense signal at the crural muscle level. MR imaging of patients with muscle disease may contribute to the in v ivo study of muscular dystrophy, its differential diagnosis and the de tection of asymptomatic patients.