3D Ultrasound Shear Wave Imaging Simulation of Heterogeneous Tissue

Shear wave imaging can quantitatively measure tissue elasticity in vivo using a 2D algebraic Helmholtz inversion (AHI) equation. The 2D AHI equation reconstructs tissue elasticity by assuming that the shear wave diffraction in the elevational direction (out-of-plane direction) is not substantial. However, the application of 2D AHI equation is limited in assessing heterogeneous tissues, as the shear wave diffraction in the elevational direction critically affects the shear modulus reconstruction. A 3D AHI equation can improve the accuracy of shear modulus reconstruction for heterogeneous tissues. In this study, a finite element (FE) based shear wave simulation was performed on an early stage of cancer and an advanced cancer tissue model. The shear modulus of FE model computed by the proposed 3D AHI equation was compared to the 2D AHI equation. The 3D AM equation substantially improved accuracy of shear modulus computation especially for the early stage of cancer model. The results from the shear modulus of inclusion by the 3D AHI equation produced the same as the input value of 150 kPa and two times lower variation than the shear modulus obtained by the 2D AHI equation.