title: Changes in calf muscle elasticity in hypogonadal males before and after testosterone substitution as monitored by magnetic resonance elastography.
abstract: OBJECTIVE
  We sought to determine whether differences in muscle elasticity between healthy age-related controls and patients with hypogonadism could be measured by a new, non-invasive method termed magnetic resonance elastography (MRE).
  
  
  METHODS
  Twelve hypogonadal (21-68 years) and twenty-seven healthy age-related men (20-76 years) were examined. In the hypogonadism group, serum testosterone levels were compared and MRE was conducted prior to and after 6 months of therapy in 6 of the 12 patients. MRE was performed by mechanically exciting the soleus muscle that was used because of its uniformly distributed muscle fibers, size, and accessibility, with a custom designed piezoelectric-actuator using a modified phase-contrast sequence. For mechanical excitation the actuator lever was placed on the anterior surface of the calf. The subjects had to maintain a force of 0-20% of their maximum voluntary contraction against a home-built footplate that was mounted on the MR table. All images were phase unwrapped and reconstructed into shear modulus elastograms using the local frequency estimation technique.
  
  
  RESULTS
  Testosterone levels were significantly higher after 6 months of treatment. A statistical difference in the shear modulus was observed prior to and after 6 months of testosterone therapy and was nearly the same as in the healthy age-related control group.
  
  
  CONCLUSIONS
  MRE seems to be a promising technique for the evaluation of therapeutic effects in patients with hypogonadism and possibly in other diseases with muscular effects.
authors.affiliation: Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Hufelandstrasse 55, 45122 Essen, Germany. katja.brauck@uni-duisburg-essen.de
authors.forename: Katja
authors.initials: K
authors.lastname: Brauck
authors.forename: Craig J
authors.initials: CJ
authors.lastname: Galbán
authors.forename: Stefan
authors.initials: S
authors.lastname: Maderwald
authors.forename: Burkhard L
authors.initials: BL
authors.lastname: Herrmann
authors.forename: Mark E
authors.initials: ME
authors.lastname: Ladd
mesh_terms: D000328:Adult; D000368:Aged; D000728:Androgens / Q000008:administration & dosage* / Q000097:blood; D016903:Drug Monitoring / Q000295:instrumentation / Q000379:methods; D004548:Elasticity; D006801:Humans; D007006:Hypogonadism / Q000188:drug therapy* / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D013739:Testosterone / Q000008:administration & dosage* / Q000097:blood
chemical_list: D000728:Androgens; D013739:Testosterone