Acoustical and physical dynamics of phagocytosed microbubble contrast agents

Paul Dayton, Jim Chomas, Aaron Lum, Scott Simon, Kathy Ferrara

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

Ultrasound contrast agents are captured and phagocytosed by activated neutrophils adherent to the venular wall in regions of inflammation. In order to determine the physical and acoustical behavior of phagocytosed microbubbles, we assessed the responses of both phagocytosed and free microbubbles with direct optical and acoustical observation. A high-speed camera was used for optical analysis of bubble radial oscillations during insonation. Observations demonstrated that phagocytosed microbubbles remain acoustically active and capable of large volumetric oscillations during an acoustic pulse despite viscous damping due to the cytoplasm. Comparison of the echoes acquired during insonation of free and phagocytosed microbubbles demonstrated that phagocytosed microbubbles produce an echo with a higher mean frequency than free microbubbles in response to a rarefaction-first single cycle pulse. This frequency difference is predicted using a Rayleigh-Plesset equation modified to describe mechanical properties of thin shells. By fitting theoretical radius-time curves to experimental data, we estimate the effective viscosity of the neutrophil cytoplasm to be approximately 12 cPs. With the treatment of neutrophil cytoplasm as a power-law fluid, this value is in agreement with cytoplasmic viscosity measurements by previous researchers. We conclude that contrast-enhanced ultrasound can detect distinct acoustic signals from microbubbles inside of neutrophils and may provide a unique tool to identify activated neutrophils at sites of inflammation.

Original languageEnglish (US)
Title of host publicationProceedings of the IEEE Ultrasonics Symposium
EditorsS.C. Schneider, M. Levy, B.R. McAvoy
Pages1877-1880
Number of pages4
Volume2
StatePublished - 2000
Event2000 IEEE Ultrasonics Symposium - San Juan, Puerto Rico
Duration: Oct 22 2000Oct 25 2000

Other

Other2000 IEEE Ultrasonics Symposium
CountryPuerto Rico
CitySan Juan
Period10/22/0010/25/00

Fingerprint

Ultrasonics
Acoustics
High speed cameras
Viscosity measurement
Damping
Viscosity
Mechanical properties
Fluids

ASJC Scopus subject areas

  • Engineering(all)

Cite this

Dayton, P., Chomas, J., Lum, A., Simon, S., & Ferrara, K. (2000). Acoustical and physical dynamics of phagocytosed microbubble contrast agents. In S. C. Schneider, M. Levy, & B. R. McAvoy (Eds.), Proceedings of the IEEE Ultrasonics Symposium (Vol. 2, pp. 1877-1880)

Acoustical and physical dynamics of phagocytosed microbubble contrast agents. / Dayton, Paul; Chomas, Jim; Lum, Aaron; Simon, Scott; Ferrara, Kathy.

Proceedings of the IEEE Ultrasonics Symposium. ed. / S.C. Schneider; M. Levy; B.R. McAvoy. Vol. 2 2000. p. 1877-1880.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Dayton, P, Chomas, J, Lum, A, Simon, S & Ferrara, K 2000, Acoustical and physical dynamics of phagocytosed microbubble contrast agents. in SC Schneider, M Levy & BR McAvoy (eds), Proceedings of the IEEE Ultrasonics Symposium. vol. 2, pp. 1877-1880, 2000 IEEE Ultrasonics Symposium, San Juan, Puerto Rico, 10/22/00.
Dayton P, Chomas J, Lum A, Simon S, Ferrara K. Acoustical and physical dynamics of phagocytosed microbubble contrast agents. In Schneider SC, Levy M, McAvoy BR, editors, Proceedings of the IEEE Ultrasonics Symposium. Vol. 2. 2000. p. 1877-1880
Dayton, Paul ; Chomas, Jim ; Lum, Aaron ; Simon, Scott ; Ferrara, Kathy. / Acoustical and physical dynamics of phagocytosed microbubble contrast agents. Proceedings of the IEEE Ultrasonics Symposium. editor / S.C. Schneider ; M. Levy ; B.R. McAvoy. Vol. 2 2000. pp. 1877-1880
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