Relating Muscle Stress and Stiffness Using Ultrasound Shear Wave Elastography
Open Access
- Author:
- Brencovich, Olivia
- Area of Honors:
- Mechanical Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Daniel Humberto Cortes Correales, Thesis Supervisor
Daniel Humberto Cortes Correales, Thesis Honors Advisor
Anne Elizabeth Martin, Faculty Reader - Keywords:
- Biomechanics
Ultrasound
Shear Wave Elastography
Passive Muscle Force
Muscle Stiffness
Shear Modulus
Tensile Stress - Abstract:
- The development of an accurate and direct calculation of individual muscle force could improve modeling of human movement patterns and the management and diagnosis of musculoskeletal disorders. Current methods for measuring individual muscle force are either invasive or require extensive assumptions and indirect calculations. Due to its non-invasive procedures, high levels of accuracy and reliability, and short data acquisition times, ultrasound shear wave elastography is emerging as a promising technique for direct calculation of individual muscle force. Using shear wave elastography, the propagation speed of an applied shear wave is measured, which can be used to calculate shear modulus—a value representative of muscle stiffness. Several studies have found a linear relationship between muscle stiffness and applied force, but the constant of proportionality varies significantly for different muscle samples. The goal of this work is to relate muscle stiffness to tensile stress to decrease variation in the constant of proportionality. In this study, the stiffness of eight tibialis cranialis muscles of eight ex vivo porcine hindlimbs when subjected to passive loading was investigated. These stiffness values were related to applied passive force and tensile stress, indicating a strong linear relationship between muscle stiffness and both force and stress. It was found that variation in the constant of proportionality is lower for stiffness-stress comparisons than for stiffness-force comparisons. Nevertheless, variation remains and suggests that a predictive model developed from these results would not accurately represent the behavior of all muscle samples. Comparison of muscle stiffness and tensile stress decreases the effect of intrinsic mechanical properties on muscle stiffness, but further testing should be completed to determine an accurate predictive model.