Nonlinearity in the interaction of ultrasound contrast agents under the periodic acoustic forcing

¹  School of Biology, The University of Nottingham - Nottingham, UK, EU
²  Department of Mathematics & Statistics, Strachclyde University - Glasgow, UK, EU
³  Department of Mathematics, Glasgow Caledonian University - Glasgow, UK, EU

Corresponding author: renata.retkute@nottingham.ac.uk

Received: 7 October 2008
Accepted: 11 January 2010

Abstract

Ultrasound contrast agents, a type of specially coated gas-filled microbubbles, provide a mean for the imaging of vascular volume and flow rate directly and in real time (Becher H. and Burns P., Handbook of Contrast Echocardiography (Springer) 2000). The response of a spherical bubble to an applied acoustic pressure can have a highly nonlinear character. On the other hand, experimental observations and theoretical calculations indicate that the presence of the shell suppresses the oscillations of the microbubble wall and results in a reduced nonlinear response. Numerical simulations of interacting contrast agents under a periodic forcing have been performed in order to study the influence of bubble-bubble interactions and of the encapsulating shell.