Correspondence - Nonlinear oscillations of deflating bubbles

Jacopo Viti, Riccardo Mori, Francesco Guidi, Michel Versluis, Nico de Jong, Piero Tortoli

Research output: Contribution to journalArticleAcademicpeer-review

10 Citations (Scopus)

Abstract

Phospholipid-coated ultrasound contrast agents may deflate or even collapse because of stress resulting from ultrasound-induced oscillations. In this work, we investigate the behavior of isolated contrast agent microbubbles during prolonged ultrasound excitation. Isolated microbubbles placed in a thin capillary tube were excited with hundreds of ultrasound pulses at a low mechanical index, and their oscillations were recorded using the Brandaris-128 ultra-high-speed camera. Results show that microbubbles undergo an irreversible, non-destructive deflation process. Such deflation seems to occur in discrete steps rather than as a continuous process; furthermore, the dynamics of the bubble change during deflation: radial oscillations, both symmetric and asymmetric around the resting radius of the bubble, occur at various stages of the deflation process. Strongly asymmetric oscillations, such as compression-only and expansion-only behavior, were also observed: notably, expansion-only behavior is associated with a rapid size reduction, whereas compression-only behavior mostly occurs without a noticeable change of the bubble radius. We hypothesize that bubble deflation results from at least two distinct phenomena, namely diffusive gas loss and lipid material shedding from the encapsulating shell.
Original languageEnglish
Pages (from-to)2818-2824
JournalIEEE transactions on ultrasonics, ferroelectrics and frequency control
Volume59
Issue number12
DOIs
Publication statusPublished - 2012

Keywords

  • METIS-290680
  • IR-82543

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