title: High-frequency ultrasound to grade disease progression in murine models of Duchenne muscular dystrophy.
abstract: OBJECTIVE
  This study used high-frequency ultrasound (HFU) imaging to assess muscle damage noninvasively in a longitudinal study of 2 transgenic murine models of Duchenne muscular dystrophy (DMD): mdx, which has mutated cytoskeletal protein dystrophin; and udx, which has mutated dystrophin and lacks another cytoskeleton protein, utrophin. The mdx group was further subdivided into exercised and nonexercised subgroups to assess exercise-induced damage.
  
  
  METHODS
  Muscle damage was assessed with HFU imaging (40 MHz) at biweekly intervals for 16 weeks. The assessment was based on the number of hyperechoic lesions, the lesion diameter, and muscle disorganization, giving a combined grade according to a 5-point scale.
  
  
  RESULTS
  High-frequency ultrasound discriminated the severity of muscle damage between wild-type and transgenic models of DMD and between mdx and udx models. Qualitative comparisons of 3-dimensional HFU images with serial histologic sections of the skeletal muscle showed the ability of ultrasound to accurately depict changes seen in the muscle architecture in vivo.
  
  
  CONCLUSIONS
  High-frequency ultrasound images soft tissue in mice at high contrast and spatial resolution, thereby showing that this microimaging modality has the capability to assess architectural changes in muscle fibers due to myotonic dystrophy-related diseases such as DMD.
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, 100 Perth Dr, London, ON N6A 5K9, Canada.
authors.forename: Nabeel
authors.initials: N
authors.lastname: Ahmad
authors.forename: Mike
authors.initials: M
authors.lastname: Bygrave
authors.forename: Rethy
authors.initials: R
authors.lastname: Chhem
authors.forename: Lisa
authors.initials: L
authors.lastname: Hoffman
authors.forename: Ian
authors.initials: I
authors.lastname: Welch
authors.forename: Robert
authors.initials: R
authors.lastname: Grange
authors.forename: Aaron
authors.initials: A
authors.lastname: Fenster
authors.forename: David
authors.initials: D
authors.lastname: Hill
authors.forename: Ting-Yim
authors.initials: TY
authors.lastname: Lee
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D018450:Disease Progression; D016189:Dystrophin / Q000235:genetics; D017353:Gene Deletion; D021621:Imaging, Three-Dimensional; D008137:Longitudinal Studies; D051379:Mice; D018101:Mice, Inbred mdx; D008822:Mice, Transgenic; D009137:Muscular Dystrophy, Animal / Q000000981:diagnostic imaging* / Q000235:genetics / Q000503:physiopathology; D020388:Muscular Dystrophy, Duchenne / Q000000981:diagnostic imaging* / Q000503:physiopathology; D010805:Physical Conditioning, Animal; D017354:Point Mutation; D014463:Ultrasonography / Q000379:methods; D049411:Utrophin / Q000235:genetics
chemical_list: D016189:Dystrophin; D049411:Utrophin