Measuring anisotropic muscle stiffness properties using elastography

• Published in: NMR in biomedicine Vol. 26; no. 11; pp. 1387 - 1394
• Main Authors: Green, M. A., Geng, G., Qin, E., Sinkus, R., Gandevia, S. C., Bilston, L. E.
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01-11-2013; Wiley Subscription Services, Inc
• Subjects: Adult; Aging; Anisotropy; diffusion tensor imaging; Elastic Modulus - physiology; Elasticity Imaging Techniques - methods; Female; Humans; Magnetic Resonance Imaging; Male; MR elastography; muscle; Muscle, Skeletal - physiology; shear modulus; stiffness; Young Adult; diffusion tensor imaging; MR elastography; stiffness; shear modulus; anisotropy; muscle
• ISSN: 0952-3480; 1099-1492
• DOI: 10.1002/nbm.2964

Physiological and pathological changes to the anisotropic mechanical properties of skeletal muscle are still largely unknown, with only a few studies quantifying changes in vivo. This study used the noninvasive MR elastography (MRE) technique, in combination with diffusion tensor imaging (DTI), to measure shear modulus anisotropy in the human skeletal muscle in the lower leg. Shear modulus measurements parallel and perpendicular to the fibre direction were made in 10 healthy subjects in the medial gastrocnemius, soleus and tibialis anterior muscles. The results showed significant differences in the medial gastrocnemius (μ‖ =0.86 ± 0.15 kPa; μ⊥ = 0.66 ± 0.19 kPa, P < 0.001), soleus (μ‖ = 0.83 ± 0.22 kPa; μ⊥ = 0.65 ± 0.13 kPa, P < 0.001) and the tibialis anterior (μ‖ = 0.78 ± 0.24 kPa; μ⊥ = 0.66 ± 0.16 kPa, P = 0.03) muscles, where the shear modulus measured in the direction parallel is greater than that measured in the direction perpendicular to the muscle fibres. No significant differences were measured across muscle groups. This study provides the first direct estimates of the anisotropic shear modulus in the triceps surae muscle group, and shows that the technique may be useful for the probing of mechanical anisotropy changes caused by disease, aging and injury. Copyright © 2013 John Wiley & Sons, Ltd.
MR elastography was used in combination with diffusion tensor imaging to measure shear modulus anisotropy in the human skeletal muscle in the lower leg. The results showed significant differences in the medial gastrocnemius and the soleus muscles, where the shear modulus measured in the direction parallel to the muscle fibres was greater than that measured perpendicular to the muscle fibres.