title: Longitudinal Evaluation of Muscle Composition Using Magnetic Resonance in 4 Boys With Duchenne Muscular Dystrophy: Case Series.
abstract: BACKGROUND
  Duchenne muscular dystrophy (DMD), an inherited recessive X chromosome-linked disease, is the most severe childhood form of muscular dystrophy. Boys with DMD experience muscle loss, with infiltration of intramuscular fat into muscles.
  
  
  OBJECTIVE
  This case series describes the progression of DMD in boys using magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). Magnetic resonance results are then compared with an established functional timed test.
  
  
  METHODS
  Four boys with DMD and 4 healthy age-matched controls were chosen from a larger cohort. Boys with DMD were assessed at 4 time points over 2 years, with controls assessed at baseline only. Progression of the disease was documented by assessing the plantar flexors using MRI and MRS techniques and by assessing ambulation using the 30-Foot Fast Walk Test.
  
  
  RESULTS
  Transverse relaxation time (T2) values were elevated in all boys with DMD at baseline. The lipid ratio increased rapidly as the disease progressed in 2 boys. Discrete changes in T2 in the other 2 boys with DMD indicated a slower disease progression. Magnetic resonance imaging and MRS allowed monitoring of the disease over all time periods regardless of ambulation status.
  
  
  CONCLUSIONS
  The magnetic resonance data were collected with 2 different magnets at 2 different field strengths (1.5 and 3.0 T). Although we corrected for this difference, care must be taken in interpreting data when different image collection systems are used. This was a case series of 4 boys with DMD taken from a larger cohort study.
  
  
  CONCLUSIONS
  Magnetic resonance imaging and MRS are objective, noninvasive techniques for measuring muscle pathology and can be used to detect discrete changes in both people who are ambulatory and those who are nonambulatory. These techniques should be considered when monitoring DMD progression and assessing efficacy of therapeutic interventions.
authors.affiliation: C.R. Senesac, PT, PhD, PCS, Department of Physical Therapy, College of Public Health and Health Professions, Health Science Center, University of Florida, PO Box 100154, Room 1134, Gainesville, FL 32610-0154 (USA). csenesac@phhp.ufl.edu.
authors.forename: Claudia R
authors.initials: CR
authors.lastname: Senesac
authors.affiliation: D.J. Lott, PT, PhD, Department of Physical Therapy, University of Florida.
authors.forename: Donovan J
authors.initials: DJ
authors.lastname: Lott
authors.affiliation: S.C. Forbes, PhD, Department of Physical Therapy, University of Florida.
authors.forename: Sean C
authors.initials: SC
authors.lastname: Forbes
authors.affiliation: S. Mathur, PT, PhD, Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Sunita
authors.initials: S
authors.lastname: Mathur
authors.affiliation: I. Arpan, PT, PhD, Department of Physical Therapy, University of Florida.
authors.forename: Ishu
authors.initials: I
authors.lastname: Arpan
authors.affiliation: E.S. Senesac, RN, BSN, Department of Physical Therapy, University of Florida.
authors.forename: Emily S
authors.initials: ES
authors.lastname: Senesac
authors.affiliation: G.A. Walter, PhD, Department of Physiology and Functional Genomics, University of Florida.
authors.forename: Glenn A
authors.initials: GA
authors.lastname: Walter
authors.affiliation: K. Vandenborne, PhD, Department of Physical Therapy, University of Florida.
authors.forename: Krista
authors.initials: K
authors.lastname: Vandenborne
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D005080:Exercise Test; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D020388:Muscular Dystrophy, Duchenne / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D016138:Walking / Q000502:physiology