Numerical analysis of ultrasound-mediated microbubble interactions in vascular systems: Effects on shear stress and vessel mechanics.

This article focuses on the development and application of a novel axisymmetric finite element numerical model to investigate microbubble oscillations within elastic microvessels under ultrasound exposure, aiming to optimize ultrasound-mediated drug delivery and diagnostic imaging. The study uniquely incorporates the viscoelastic properties of the microbubble shell and various mechanical models of the microvessel wall to evaluate their combined effects on microbubble dynamics and the induced shear stress on vessel walls. Results demonstrate that acoustic parameters (pressure amplitude and frequency), microbubble shell elasticity and viscosity, vessel mechanical properties, and the microvessel-to-bubble size ratio significantly influence microbubble oscillations and shear stress levels, with peak shear stresses reaching up to 15.6 kPa under certain conditions. These findings provide critical insights for tailoring ultrasound parameters and microbubble characteristics to enhance therapeutic efficacy while minimizing vascular injury risks. The study acknowledges limitations such as the assumption of spherical bubble shape and suggests future work to include non-spherical oscillations and multi-bubble interactions for improved clinical relevance.