title: Ultrasonography detects early laryngeal muscle atrophy in an equine neurectomy model.
abstract: BACKGROUND
  A unilateral neurectomy model was used to study the relationship between histologic and ultrasonographic tissue characteristics during muscle atrophy over time.
  
  
  METHODS
  This investigation was an in vivo experimental study in an equine model (n = 28). Mean pixel intensity of ultrasonographic images was measured, a muscle appearance grade was assigned weekly, and muscles were harvested from 4 to 32 weeks. Minimum fiber diameter, fiber density per unit area, percent collagen, percent fat, and fiber type profile were measured from muscle cryosections and correlated with the ultrasonographic parameters.
  
  
  RESULTS
  A significant relationship was identified between collagen content, minimum fiber diameter, and ultrasonographic muscle appearance by as early as 8 weeks. There was no apparent association between fat content of muscle and the ultrasonographic appearance of atrophy before 28 weeks.
  
  
  CONCLUSIONS
  Early muscle atrophy before fatty infiltration is detectable with ultrasound. The effect of muscle collagen content on echointensity may be mediated by reduced fiber diameter.
authors.affiliation: Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, N1G 2W1, Canada.
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Chalmers
authors.affiliation: Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Jeff
authors.initials: J
authors.lastname: Caswell
authors.affiliation: Department of Clinical Sciences and Services, Royal Veterinary College, University of London, London, UK.
authors.forename: Justin
authors.initials: J
authors.lastname: Perkins
authors.affiliation: Department of Clinical Sciences and Services, Royal Veterinary College, University of London, London, UK.
authors.forename: David
authors.initials: D
authors.lastname: Goodwin
authors.affiliation: Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, N1G 2W1, Canada.
authors.forename: Laurent
authors.initials: L
authors.lastname: Viel
authors.affiliation: Department of Clinical Sciences, New York State College of Veterinary Medicine, Cornell University, Ithaca, New York, USA.
authors.forename: Norm G
authors.initials: NG
authors.lastname: Ducharme
authors.affiliation: Department of Clinical Sciences and Services, Royal Veterinary College, University of London, London, UK.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Piercy
mesh_terms: D000818:Animals; D005260:Female; D006736:Horses; D007821:Laryngeal Muscles / Q000000981:diagnostic imaging* / Q000473:pathology*; D008297:Male; D023421:Models, Animal; D009133:Muscular Atrophy / Q000000981:diagnostic imaging* / Q000473:pathology*; D014463:Ultrasonography
keywords: atrophy; histology; larynx; muscle; ultrasound