title: Effectiveness of diffusion tensor imaging in assessing disease severity in Duchenne muscular dystrophy: preliminary study.
abstract: BACKGROUND
  There is currently a lack of suitable objective endpoints to measure disease progression in Duchenne muscular dystrophy (DMD). Emerging research suggests that diffusion tensor imaging (DTI) has potential as an outcome measure for the evaluation of skeletal muscle injury.
  
  
  OBJECTIVE
  The objective of this study was to evaluate the potential of DTI as quantitative magnetic resonance imaging (MRI) markers of disease severity in DMD.
  
  
  METHODS
  Thirteen consecutive boys (8.9 years ± 3.0 years) with DMD were evaluated using DTI. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were compared with clinical outcome measures of manual muscle testing and MRI determinations of muscle fat fraction (MFF) in the right lower extremity.
  
  
  RESULTS
  Both MRI measures of FA and ADC strongly correlated with age and muscle strength. Values for FA positively correlated with age and negatively correlated with muscle strength (r = 0.78 and -0.96; both P ≤ 0.002) while measures of ADC negatively correlated age, but positively correlated with muscle strength (r = -0.87 and 0.83; both P ≤ 0.0004). Additionally, ADC and FA strongly correlated with MFF (r = -0.891 and 0.894, respectively; both P ≤ 0.0001). Mean MMF was negatively correlated with muscle strength (r = -0.89, P = 0.0001).
  
  
  CONCLUSIONS
  DTI measures of muscle structure strongly correlated with muscle strength and adiposity in boys with DMD in this pilot study, although these markers may be more reflective of fat replacement rather than muscle damage in later stages of the disease. Further studies in presymptomatic younger children are needed to assess the ability of DTI to detect early changes in DMD.
authors.affiliation: Department of Radiology, Children's Hospital Los Angeles, MS #81, 4650 Sunset Blvd., Los Angeles, CA, 90027, USA, sponrartana@chla.usc.edu.
authors.forename: Skorn
authors.initials: S
authors.lastname: Ponrartana
authors.forename: Leigh
authors.initials: L
authors.lastname: Ramos-Platt
authors.forename: Tishya Anne Leong
authors.initials: TA
authors.lastname: Wren
authors.forename: Houchun Harry
authors.initials: HH
authors.lastname: Hu
authors.forename: Thomas Gardner
authors.initials: TG
authors.lastname: Perkins
authors.forename: Jonathan Mawlin
authors.initials: JM
authors.lastname: Chia
authors.forename: Vicente
authors.initials: V
authors.lastname: Gilsanz
mesh_terms: D000293:Adolescent; D002648:Child; D056324:Diffusion Tensor Imaging / Q000379:methods*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D020388:Muscular Dystrophy, Duchenne / Q000175:diagnosis*; D010808:Physical Examination; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index