Changes in calf muscle elasticity in hypogonadal males before and after testosterone substitution as monitored by magnetic resonance elastography

Abstract

PURPOSE: 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). MATERIALS AND 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. CONCLUSION: 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.