title: Quantitative muscle ultrasound in Duchenne muscular dystrophy: a comparison of techniques.
abstract: BACKGROUND
  Muscle pathology in Duchenne muscular dystrophy (DMD) can be quantified using ultrasound by measuring either the amplitudes of sound-waves scattered back from the tissue [quantitative backscatter analysis (QBA)] or by measuring these backscattered amplitudes after compression into grayscale levels (GSL) obtained from the images.
  
  
  METHODS
  We measured and compared QBA and GSL from 6 muscles of 25 boys with DMD and 25 healthy subjects, aged 2-14 years, with age and, in DMD, with function (North Star Ambulatory Assessment).
  
  
  RESULTS
  Both QBA and GSL were measured reliably (intraclass correlation ≥ 0.87) and were higher in DMD than controls (P < 0.0001). In DMD, average QBA and GSL measured from superficial regions of muscle increased (rho ≥ 0.47, P < 0.05) with both higher age and worse function; in contrast, GSL measured from whole regions of muscle did not.
  
  
  CONCLUSIONS
  QBA and GSL measured from superficial regions of muscle can similarly quantify muscle pathology in DMD.
authors.affiliation: The Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
authors.forename: Irina
authors.initials: I
authors.lastname: Shklyar
authors.forename: Tom R
authors.initials: TR
authors.lastname: Geisbush
authors.forename: Aleksandar S
authors.initials: AS
authors.lastname: Mijialovic
authors.forename: Amy
authors.initials: A
authors.lastname: Pasternak
authors.forename: Basil T
authors.initials: BT
authors.lastname: Darras
authors.forename: Jim S
authors.initials: JS
authors.lastname: Wu
authors.forename: Seward B
authors.initials: SB
authors.lastname: Rutkove
authors.forename: Craig M
authors.initials: CM
authors.lastname: Zaidman
mesh_terms: D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D003936:Diagnosis, Computer-Assisted; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging* / Q000473:pathology*; D020388:Muscular Dystrophy, Duchenne / Q000473:pathology*; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D014463:Ultrasonography
keywords: Duchenne muscular dystrophy; biomarker; muscle; myopathy; ultrasound