Constitutive parameter identification of transtibial residual limb soft tissue using ultrasound indentation and shear wave elastography

TL;DR

This paper introduces a novel, efficient method combining ultrasound indentation and shear wave elastography with finite element analysis to identify soft tissue parameters in transtibial residual limbs, aiding prosthetic design and muscle health monitoring.

Contribution

It presents a new approach that reduces computational time and equipment needs for patient-specific tissue property identification using ultrasound and elastography.

Findings

Effective local shear modulus measurement during ultrasound indentation.

Potential for improved prosthetic socket design through realistic tissue modeling.

Broader applications in muscle health and disease monitoring.

Abstract

Finite element analysis (FEA) can be used to evaluate applied interface pressures and internal tissue strains for computational prosthetic socket design. This type of framework requires realistic patient-specific limb geometry and constitutive properties. In recent studies, indentations and inverse FEA with MRI-derived 3D patient geometries were used for constitutive parameter identification. However, long computational times and use of specialized equipment presents challenges for clinical deployment. In this study, we present a novel approach for constitutive parameter identification using a combination of FEA, ultrasound indentation, and shear wave elastography. Local shear modulus measurement using elastography during an ultrasound indentation experiment has particular significance for biomechanical modeling of the residual limb since there are known regional dependencies of soft tissue properties such as varying levels of scarring and atrophy. Beyond prosthesis design, this work has broader implications to the fields of muscle health and monitoring of disease progression.