Threshold of fragmentation for ultrasonic contrast agents

J. E. Chomas, P. Dayton, D. May, K. Ferrara

Research output: Contribution to journalArticle

221 Scopus citations

Abstract

Ultrasound contrast agents are small microbubbles that can be readily destroyed with sufficient acoustic pressure, typically, at a frequency in the low megaHertz range. Microvascular flow rate may be estimated by destroying the contrast agent in a vascular bed, and estimating the rate of flow of contrast agents back into the vascular bed. Characterization of contrast agent destruction provides important information for the design of this technique. In this paper, high-speed optical observation of an ultrasound contrast agent during acoustic insonation is performed. The resting diameter is shown to be a significant parameter in the prediction of microbubble destruction, with smaller diameters typically correlated with destruction. Pressure, center frequency, and transmission phase are each shown to have a significant effect on the fragmentation threshold. A linear prediction for the fragmentation threshold as a function of pressure, when normalized by the resting diameter, has a rate of change of 300 kPa/μm for the range of pressures from 310 to 1200 kPa, and a two-cycle excitation pulse with a center frequency of 2.25 MHz. A linear prediction for the fragmentation threshold as a function of frequency, when normalized by the resting diameter, has a rate of change of -1.2 MHz/μm for a transmission pressure of 800 kPa, and a two-cycle excitation pulse with a range of frequencies from 1 to 5 MHz.

Original languageEnglish (US)
Pages (from-to)141-150
Number of pages10
JournalJournal of Biomedical Optics
Volume6
Issue number2
DOIs
StatePublished - Apr 2001

Keywords

  • Blood flow
  • Contrast agents
  • Fragmentation
  • Optical observation
  • Ultrasound

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Radiology Nuclear Medicine and imaging
  • Atomic and Molecular Physics, and Optics
  • Radiological and Ultrasound Technology

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