Nonlinear behavior of ultrasound contrast agent microbubbles and why shell buckling matters

Michel Versluis*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

1 Citation (Scopus)

Abstract

Contrast-enhanced ultrasound imaging relies on the nonlinear scattering of microbubbles suspended in an ultrasound contrast agent. The bubble dynamics is described by a Rayleigh-Plesset-type equation, and the success of harmonic imaging using contrast agents has always been attributed to the nonlinear behavior predicted by this equation. A surfactant layer of phospholipids stabilizes the microbubbles and it has always been assumed that the visco-elastic properties of the coating lead to an increased stiffness and additional damping of the radial dynamics, hence to a reduction of the nonlinear response of the bubbles. Here we show that the coating material in fact leads to an increased nonlinear bubble response even at low acoustic pressures where the traditional models for coated as well as uncoated bubbles would only predict linear behavior. For a selection of bubbles we show a pronounced skewness of the resonance curve for increasing pressures to be the origin of the 'threshold' behavior, where it appears as if the bubbles are activated only at elevated pressures. Another set of bubbles shows a 'compression-only' behavior, where the bubbles are observed to efficiently compress, while their expansion is highly reduced. Moreover, the majority of these bubbles display a very strong subharmonic response. The shell-buckling model by Marmottant et al. accounts for buckling and rupture of the shell and captures all of the above cases for a unique set of the shell parameters, the relevant parameter being the phospholipid concentration at the bubble interface.

Original languageEnglish
Title of host publication20th International Congress on Acoustics 2010, ICA 2010 - Incorporating Proceedings of the 2010 Annual Conference of the Australian Acoustical Society
Pages4196-4201
Number of pages6
Publication statusPublished - 1 Dec 2010
Event20th International Congress on Acoustics, ICA 2010 - Sydney, Australia
Duration: 23 Aug 201027 Aug 2010
Conference number: 20
https://www.acoustics.asn.au/conference_proceedings/ICA2010/cdrom-ICA2010/index.htm

Publication series

Name20th International Congress on Acoustics 2010, ICA 2010 - Incorporating Proceedings of the 2010 Annual Conference of the Australian Acoustical Society
Volume5

Conference

Conference20th International Congress on Acoustics, ICA 2010
Abbreviated titleICA 2010
CountryAustralia
CitySydney
Period23/08/1027/08/10
Internet address

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    Versluis, M. (2010). Nonlinear behavior of ultrasound contrast agent microbubbles and why shell buckling matters. In 20th International Congress on Acoustics 2010, ICA 2010 - Incorporating Proceedings of the 2010 Annual Conference of the Australian Acoustical Society (pp. 4196-4201). (20th International Congress on Acoustics 2010, ICA 2010 - Incorporating Proceedings of the 2010 Annual Conference of the Australian Acoustical Society; Vol. 5).