A Finite Element Study of Ultrasound Elastography Using Shear Wave Interference Patterns Generated by Miniature Surface Sources

Elastography as one of the most promising non-invasive methods in the diagnosis of liver diseases is attracting much attention. An interesting technique which is independent of imaging rate uses shear wave interference patterns induced by two external stimulation sources. In this article a 3D finite element model of liver tissue with superficial mechanical stimulation is presented through which, the possibility of using shear wave interference patterns to determine the type of liver fibrosis is investigated. In addition, the effect of various stimulation characteristics on the propagation of elastic waves and formation of shear wave interference patterns can be measured. Besides, ultrasound imaging and methods based on cross correlation are used to find target displacements caused by interference of shear waves. According to the results, the type of fibrosis was determined at all stages without error, and the mean elasticity estimation error of 4.98% was obtained for the finite element model.