Imaging of Shear Waves Induced by Lorentz Force in Soft Tissues

TL;DR

This paper demonstrates that Lorentz force can generate detectable shear waves in soft tissues, enabling new methods for elasticity imaging using electromagnetic fields and ultrasound. The approach is validated through experiments, modeling, and tissue analysis.

Contribution

It introduces a novel technique to induce shear waves in soft tissues via Lorentz force, combining electromagnetic stimulation with ultrasound detection, supported by experiments and simulations.

Findings

Lorentz force induces measurable displacements in soft phantoms.

Shear waves generated by Lorentz force can be detected and used for elasticity estimation.

The method accurately estimates tissue elasticity, demonstrated on swine liver.

Abstract

This study presents the first observation of elastic shear waves generated in soft solids using a dynamic electromagnetic field. The first and second experiments of this 5 study showed that Lorentz force can induce a displacement in a soft phantom and that this displacement was detectable by an ultrasound scanner using speckle-tracking algorithms. For a 100 mT magnetic field and a 10 ms, 100 mA peak-to-peak electrical burst, the displacement reached a magnitude of 1 um. In the third experiment, we showed that Lorentz force can induce shear waves in a phantom. A physical model 10 using electromagnetic and elasticity equations was proposed. Computer simulations were in good agreement with experimental results. The shear waves induced by Lorentz force were used in the last experiment to estimate the elasticity of a swine liver sample.