title: Severe paraspinal muscle involvement in facioscapulohumeral muscular dystrophy.
abstract: OBJECTIVE
  In this study, involvement of paraspinal muscles in 50 patients with facioscapulohumeral dystrophy (FSHD) was evaluated using MRI.
  
  
  METHODS
  The Dixon MRI technique was used in this observational study to quantify muscle fat content of paraspinal and leg muscles. Muscle strength in the neck, back, and legs was assessed with a handheld dynamometer. All subjects completed the Low Back Pain Rating Scale questionnaire. MRI findings were compared with 31 age-matched controls and correlated to muscle strength, back pain, and MRI findings in lower extremities.
  
  
  RESULTS
  The fat fraction in muscles was significantly higher in patients with FSHD than in controls: paraspinal fat fraction was 38% in patients vs 20% in controls, thigh fat fraction was 36% vs 11%, and calf fat fraction was 37% vs 11%. Increased paraspinal fat fraction correlated with D4Z4 repeat size, FSHD severity score, fat fraction of the thigh, and muscle strength in the back. The prevalence of back pain was 3 times higher in patients with FSHD vs controls, but back pain did not correlate with the paraspinal fat fraction.
  
  
  CONCLUSIONS
  This study shows a prominent involvement of paraspinal muscles in patients with FSHD, which should be considered in the management of this condition.
authors.affiliation: From the Neuromuscular Research Unit, Department of Neurology (J.R.D., C.R.V., J.V.) and Department of Diagnostic Radiology (C.T.), Rigshospitalet, University of Copenhagen, Denmark. julia.rebecka.dahlqvist@regionh.dk.
authors.forename: Julia R
authors.initials: JR
authors.lastname: Dahlqvist
authors.affiliation: From the Neuromuscular Research Unit, Department of Neurology (J.R.D., C.R.V., J.V.) and Department of Diagnostic Radiology (C.T.), Rigshospitalet, University of Copenhagen, Denmark.
authors.forename: Christoffer R
authors.initials: CR
authors.lastname: Vissing
authors.affiliation: From the Neuromuscular Research Unit, Department of Neurology (J.R.D., C.R.V., J.V.) and Department of Diagnostic Radiology (C.T.), Rigshospitalet, University of Copenhagen, Denmark.
authors.forename: Carsten
authors.initials: C
authors.lastname: Thomsen
authors.affiliation: From the Neuromuscular Research Unit, Department of Neurology (J.R.D., C.R.V., J.V.) and Department of Diagnostic Radiology (C.T.), Rigshospitalet, University of Copenhagen, Denmark.
authors.forename: John
authors.initials: J
authors.lastname: Vissing
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis / Q000503:physiopathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D020391:Muscular Dystrophy, Facioscapulohumeral / Q000473:pathology / Q000503:physiopathology*; D064170:Paraspinal Muscles / Q000473:pathology / Q000503:physiopathology*; D055815:Young Adult