title: Real-time sonography to estimate muscle thickness: comparison with MRI and CT.
abstract: OBJECTIVE
  We investigated the feasibility of using real-time sonography to measure muscle thickness. Clinically, this technique would be used to measure the thickness of human muscles in which intramuscular microstimulators have been implanted to treat or prevent disuse atrophy.
  
  
  METHODS
  Porcine muscles were implanted with microstimulators and imaged with sonography, MRI, and CT to assess image artifacts created by the microstimulators and to design protocols for image alignment between methods. Sonography and MRI were then used to image the deltoid and supraspinatus muscles of 6 healthy human subjects.
  
  
  RESULTS
  Microstimulators could be imaged with all 3 methods, producing only small imaging artifacts. Muscle-thickness measurements agreed well between methods, particularly when external markers were used to precisely align the imaging planes. The correlation coefficients for sonographic and MRI measurements were 0.96 for the supraspinatus and 0.97 for the deltoid muscle. Repeated sonographic measurements had a low coefficient of variation: 2.3% for the supraspinatus and 3.1% for the deltoid muscle.
  
  
  CONCLUSIONS
  Real-time sonography is a relatively simple and inexpensive method of accurately measuring muscle thickness as long as the operator adheres to a strict imaging protocol and avoids excessive pressure with the transducer.
authors.affiliation: Department of Physiology, Queen's University and Kingston General Hospital, Kingston, Ontario K7L 3N6, Canada.
authors.forename: A C
authors.initials: AC
authors.lastname: Dupont
authors.forename: E E
authors.initials: EE
authors.lastname: Sauerbrei
authors.forename: P V
authors.initials: PV
authors.lastname: Fenton
authors.forename: P C
authors.initials: PC
authors.lastname: Shragge
authors.forename: G E
authors.initials: GE
authors.lastname: Loeb
authors.forename: F J
authors.initials: FJ
authors.lastname: Richmond
mesh_terms: D000328:Adult; D000818:Animals; D000886:Anthropometry / Q000379:methods; D004599:Electric Stimulation Therapy; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D013552:Swine; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography