Noninvasive microbubble-based pressure measurements: a simulation study

Michiel Postema, M.A.B. Postema, Ayache Bouakaz, N. de Jong

Research output: Contribution to journalArticleAcademicpeer-review

25 Citations (Scopus)

Abstract

This paper describes a noninvasive method to measure local hydrostatic pressures in fluid filled cavities. The method is based on the disappearance time of a gas bubble, as the disappearance time is related to the hydrostatic pressure. When a bubble shrinks, its response to ultrasound changes. From this response, the disappearance time, and with it the hydrostatic pressure, can be determined. We investigated the applicability of the gases Ar, C3F8, Kr, N2, Ne, and SF6, based on their diffusive properties. For pressure measurements with a limited duration, e.g. 150 ms, Kr and Ar bubbles are most suitable, since they are most sensitive to pressure change. If there is also a limitation to bubble size, e.g. a maximum diameter of 6 lm, SF6 is most suitable. We present improvements of a method that correlates the duration of the decay of the fundamental ultrasound response to the hydrostatic overpressure. We propose to correlate the duration until subharmonic occurrence in combination with its decay, to hydrostatic overpressure, since the subharmonic decays more rapidly than the fundamental response. For a dissolving Ar gas bubble with an initial diameter of 14 lm, the overpressure can be determined 4 times as precise from the decay of the subharmonic response as from the decay of the fundamental response. Overpressures as small as 11 mmHg may be discriminated with this method.
Original languageUndefined
Pages (from-to)759-762
Number of pages4
JournalUltrasonics
Volume42
Issue number1-9
DOIs
Publication statusPublished - 2004

Keywords

  • Microbubble diffusion
  • Noninvasive pressure measurements
  • IR-50157
  • METIS-223479
  • Subharmonics

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