Interaction between microbubble and elastic microvessel in low frequency ultrasound field using finite element method

Abstract

The interaction between microbubble and elastic microvessel wall has been hypothesized to be important in the mechanisms of therapeutic ultrasound applications. In this study, a 2D axisymmetric finite element numerical model is established to study the interaction between elastic microvessel wall and oscillating microbubble in low frequency ultrasound field using fluid solid interaction method. The numerical results show that the bubble oscillation induces the vessel wall dilation and depression. The von Mises stress distribution over the microvessel wall is heterogeneous and the maximum value of the midpoint on the inner vessel wall could reach 0.23 MPa and 1.32 MPa under PNP 0.2 MPa and 0.5 MPa, respectively. When the bubble collapses, the circumferential stress decreases rapidly and the transmural pressure increases dramatically. Noticeably, the circumferential stress becomes compressive with the maximum magnitude 1.83 MPa under PNP 0.5 MPa, larger than the maximum tension value. It is possible that the rapid compression stress during bubble collapse plays important role in mechanical effect on microvessel wall endothelial lining disruption.