title: Forced vibrations of a bubble in a liquid-filled elastic vessel.
abstract: There is increasing demand for accurate characterization of the in vivo behavior of microbubble agents used for ultrasound imaging and therapy. This study examines bubble-vessel interaction, in particular the propagation of disturbances along the vessel wall. Finite element simulations of a 3 μm radius microbubble suspended in a viscous liquid and enclosed in a 4 μm radius elastic vessel were performed, and the results compared with existing analytical results for wave propagation in elastic liquid-filled tubes. The vessel wall was shown to have a significant effect upon the amplitude of bubble oscillation and hence acoustic radiation from it, as well as distension of the vessel wall. It was found that the most important factor was the ratio of the excitation frequency to the natural "ring" frequency of the vessel which in turn depends upon its dimensions and mechanical properties. As this ratio increases, the motion of the vessel wall becomes increasingly localized to the site of the bubble. It was also shown that the validity of the results obtained using the applied model of vessel elasticity is limited to frequencies below the ring frequency, and this should be taken into account in the development of protocols for ultrasound safety and/or therapeutic procedures.
authors.affiliation: Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom. s.martynov@ucl.ac.uk
authors.forename: Sergey
authors.initials: S
authors.lastname: Martynov
authors.forename: Erik
authors.initials: E
authors.lastname: Kostson
authors.forename: Nader
authors.initials: N
authors.lastname: Saffari
authors.forename: Eleanor
authors.initials: E
authors.lastname: Stride
mesh_terms: D003198:Computer Simulation; D003287:Contrast Media; D004548:Elasticity; D020342:Finite Element Analysis; D045423:Microbubbles; D008962:Models, Theoretical; D009716:Numerical Analysis, Computer-Assisted; D011312:Pressure; D015203:Reproducibility of Results; D013997:Time Factors; D014465:Ultrasonics; D014732:Vibration
chemical_list: D003287:Contrast Media