title: Quantitative muscle ultrasound detects disease progression in Duchenne muscular dystrophy.
abstract: OBJECTIVE
  We assessed changes in quantitative muscle ultrasound data in boys with Duchenne muscular dystrophy (DMD) and healthy controls to determine whether ultrasound can serve as a biomarker of disease progression. Two approaches were used: gray scale level (GSL), measured from the ultrasound image, and quantitative backscatter analysis (QBA), measured directly from the received echoes.
  
  
  METHODS
  GSL and QBA were obtained from 6 unilateral arm/leg muscles in 36 boys with DMD and 28 healthy boys (age = 2-14 years) for up to 2 years. We used a linear mixed effects model with random intercept and slope terms to compare trajectories of GSL, QBA, and functional assessments. We analyzed separately a subset of boys who initiated corticosteroids.
  
  
  RESULTS
  Compared to healthy boys, increasing GSL in DMD boys >7.0 years old was first identified at 6 months (eg, anterior forearm slope difference of 1.16 arbitrary units/mo, p = 0.004, 95% confidence interval [CI] = 0.38-1.94); in boys ≤ 7 years old, differences in GSL first appeared at 12 months (0.82 arbitrary units/mo, p = 0.04, 95% CI = 0.075-1.565, in rectus femoris). QBA performed similarly to GSL (eg, DMD boys > 7 years old: 0.41dB/mo, p = 0.01, 95% CI = 0.096-0.72, in anterior forearm at 6 months). Ultrasound identified differences earlier than functional measures including 6-minute walk and supine-to-stand tests. However, neither QBA nor GSL showed an effect of corticosteroid initiation.
  
  
  CONCLUSIONS
  QBA performs similarly to GSL, and both appear more sensitive than functional assessments for detecting muscle deterioration in DMD. Additional studies will be required to determine whether quantitative muscle ultrasound can detect therapeutic efficacy. Ann Neurol 2017;81:633-640.
authors.affiliation: Department of Neurology, Washington University in St Louis, St Louis, MO.
authors.forename: Craig M
authors.initials: CM
authors.lastname: Zaidman
authors.affiliation: Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Jim S
authors.initials: JS
authors.lastname: Wu
authors.affiliation: Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA.
authors.forename: Kush
authors.initials: K
authors.lastname: Kapur
authors.affiliation: Department of Physical Therapy Services and Occupational Therapy Services, Boston Children's Hospital, Boston, MA.
authors.forename: Amy
authors.initials: A
authors.lastname: Pasternak
authors.affiliation: Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA.
authors.forename: Lavanya
authors.initials: L
authors.lastname: Madabusi
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA.
authors.forename: Sung
authors.initials: S
authors.lastname: Yim
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA.
authors.forename: Adam
authors.initials: A
authors.lastname: Pacheck
authors.affiliation: Department of Neurology, Washington University in St Louis, St Louis, MO.
authors.forename: Heather
authors.initials: H
authors.lastname: Szelag
authors.affiliation: Department of Neurology, Washington University in St Louis, St Louis, MO.
authors.forename: Tim
authors.initials: T
authors.lastname: Harrington
authors.affiliation: Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA.
authors.forename: Basil T
authors.initials: BT
authors.lastname: Darras
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA.
authors.forename: Seward B
authors.initials: SB
authors.lastname: Rutkove
mesh_terms: D000293:Adolescent; D001132:Arm / Q000000981:diagnostic imaging; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D006801:Humans; D007866:Leg / Q000000981:diagnostic imaging; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging*; D020388:Muscular Dystrophy, Duchenne / Q000000981:diagnostic imaging*; D014463:Ultrasonography / Q000379:methods*