title: Magnetization transfer imaging of skeletal muscle in autosomal recessive limb girdle muscular dystrophy.
abstract: OBJECTIVE
  The purpose of this work was to characterize magnetization transfer (MT) contrast of skeletal muscles in limb girdle muscular dystrophy (LGMD).
  
  
  METHODS
  The calf muscles of five LGMD patients and 10 normal volunteers were imaged with an off-resonance MT suppression pulse applied to T1-weighted images. MT suppression ratios were calculated for anterior tibialis, posterior tibialis, soleus, and gastrocnemius muscles in the LGMD and control groups. The relationship between MT of individual muscles and the duration of LGMD symptoms was determined.
  
  
  RESULTS
  Strong MT contrast was observed in normal calf muscles, with mean (+/-SD) suppression ratios ranging from 37.9% (+/-3.0) to 41.1% (+/-2.1). In diseased muscle, MT signal suppression ranged from 11 to 38%, demonstrating an inverse relationship between symptom duration and suppression ratios. MT contrast in the LGMD patients, as a reflection of muscle tissue integrity, was preserved in posterior or anterior tibialis, soleus, and gastrocnemius muscles, respectively. Suppression ratios were dramatically reduced in muscles with gross fatty infiltration but also were reduced in muscle tissues without visual evidence of fatty infiltration.
  
  
  CONCLUSIONS
  MT imaging provides a quantitative measure of pathologic changes occurring within the skeletal muscles of patients with LGMD relative to normal and may be useful in evaluating disease extent, progression, and response to new therapies as they become available.
authors.affiliation: Department of Radiology, Medical College of Wisconsin, Milwaukee, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: McDaniel
authors.forename: J L
authors.initials: JL
authors.lastname: Ulmer
authors.forename: R W
authors.initials: RW
authors.lastname: Prost
authors.forename: M B
authors.initials: MB
authors.lastname: Franczak
authors.forename: S
authors.initials: S
authors.lastname: Jaradeh
authors.forename: C A
authors.initials: CA
authors.lastname: Hamilton
authors.forename: L P
authors.initials: LP
authors.lastname: Mark
mesh_terms: D000293:Adolescent; D000328:Adult; D005808:Genes, Recessive; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology*; D009136:Muscular Dystrophies / Q000473:pathology*