title: Quantitative assessment of skeletal muscle degeneration in patients with myotonic dystrophy type 1 using MRI.
abstract: OBJECTIVE
  To identify MRI biomarkers that could be used to follow disease progression and therapeutic efficacy in one individual muscle in patients with myotonic dystrophy type 1 (DM1).
  
  
  METHODS
  Lower limb MRI and maximal ankle dorsiflexor strength assessment, using a hand-held dynamometer, were performed in 19 DM1 patients and 6 control subjects. The volume of residual muscle tissue of Tibialis Anterior (TA) muscle was chosen as an index for muscle atrophy, and the T2-relaxation-time of the residual muscle tissue was measured to evaluate edema-like lesions. The fat-to-water ratio was assessed using three-point Dixon images to quantify fat infiltration in the entire muscle.
  
  
  RESULTS
  The intra-observer variability of MRI indices (∼5.2% for the residual muscle tissue volume and 2.5% for the fat-to-water ratio) was lower than that of the dorsiflexor torque measurement (∼11.5%). A high correlation (r = 0.91) was found between maximal ankle dorsiflexor strength and residual TA muscle tissue volume in DM1 patients. Increases in the fat-to-water ratio and T2-relaxation-time were associated with a decrease in maximal ankle dorsiflexor strength.
  
  
  CONCLUSIONS
  MRI appears as a noninvasive method which can be used to follow disease progression and therapeutic efficacy.
authors: Université de Lyon, Université Lyon 1, Faculté de médecine Lyon Est, Lyon, France. bassem.hiba@rmsb.u-bordeaux2.fr
authors: Bassem
authors: B
authors: Hiba
authors: Nathalie
authors: N
authors: Richard
authors: Luc J
authors: LJ
authors: Hébert
authors: Chantal
authors: C
authors: Coté
authors: Mimoun
authors: M
authors: Nejjari
authors: Christoph
authors: C
authors: Vial
authors: Françoise
authors: F
authors: Bouhour
authors: Jack
authors: J
authors: Puymirat
authors: Marc
authors: M
authors: Janier
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000473:pathology*; D015415:Biomarkers / Q000032:analysis; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000473:pathology*; D009133:Muscular Atrophy / Q000473:pathology*; D009223:Myotonic Dystrophy / Q000473:pathology*; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric
chemical_list: D015415:Biomarkers