Phase change events of volatile liquid perfluorocarbon contrast agents produce unique acoustic signatures

Paul S. Sheeran, Terry O Matsunaga, Paul A. Dayton

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

Phase-change contrast agents (PCCAs) provide a dynamic platform to approach problems in medical ultrasound (US). Upon US-mediated activation, the liquid core vaporizes and expands to produce a gas bubble ideal for US imaging and therapy. In this study, we demonstrate through high-speed video microscopy and US interrogation that PCCAs composed of highly volatile perfluorocarbons (PFCs) exhibit unique acoustic behavior that can be detected and differentiated from standard microbubble contrast agents. Experimental results show that when activated with short pulses PCCAs will over-expand and undergo unforced radial oscillation while settling to a final bubble diameter. The size-dependent oscillation phenomenon generates a unique acoustic signal that can be passively detected in both time and frequency domain using confocal piston transducers with an 'activate high' (8 MHz, 2 cycles), 'listen low' (1 MHz) scheme. Results show that the magnitude of the acoustic 'signature' increases as PFC boiling point decreases. By using a band-limited spectral processing technique, the droplet signals can be isolated from controls and used to build experimental relationships between concentration and vaporization pressure. The techniques shown here may be useful for physical studies as well as development of droplet-specific imaging techniques.

Original languageEnglish (US)
Pages (from-to)379-401
Number of pages23
JournalPhysics in Medicine and Biology
Volume59
Issue number2
DOIs
StatePublished - Jan 20 2014

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Fluorocarbons
Acoustics
Contrast Media
Microbubbles
Video Microscopy
Volatilization
Transducers
Ultrasonography
Gases
Pressure
Therapeutics

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology

Cite this

Phase change events of volatile liquid perfluorocarbon contrast agents produce unique acoustic signatures. / Sheeran, Paul S.; Matsunaga, Terry O; Dayton, Paul A.

In: Physics in Medicine and Biology, Vol. 59, No. 2, 20.01.2014, p. 379-401.

Research output: Contribution to journalArticle

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