title: Contrast-enhanced ultrasound imaging and in vivo circulatory kinetics with low-boiling-point nanoscale phase-change perfluorocarbon agents.
abstract: Many studies have explored phase-change contrast agents (PCCAs) that can be vaporized by an ultrasonic pulse to form microbubbles for ultrasound imaging and therapy. However, few investigations have been published on the utility and characteristics of PCCAs as contrast agents in vivo. In this study, we examine the properties of low-boiling-point nanoscale PCCAs evaluated in vivo and compare data with those for conventional microbubbles with respect to contrast generation and circulation properties. To do this, we develop a custom pulse sequence to vaporize and image PCCAs using the Verasonics research platform and a clinical array transducer. Results indicate that droplets can produce contrast enhancement similar to that of microbubbles (7.29 to 18.24 dB over baseline, depending on formulation) and can be designed to circulate for as much as 3.3 times longer than microbubbles. This study also reports for the first time the ability to capture contrast washout kinetics of the target organ as a measure of vascular perfusion.
authors.affiliation: Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Sheeran
authors.affiliation: Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA.
authors.forename: Juan D
authors.initials: JD
authors.lastname: Rojas
authors.affiliation: Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA.
authors.forename: Connor
authors.initials: C
authors.lastname: Puett
authors.affiliation: Department of Biomedical Engineering, North Carolina State University, Raleigh, North Carolina, USA.
authors.forename: Jordan
authors.initials: J
authors.lastname: Hjelmquist
authors.affiliation: Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA.
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Arena
authors.affiliation: Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA. Electronic address: Padayton@email.unc.edu.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Dayton
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000737:chemistry* / Q000493:pharmacokinetics*; D005466:Fluorocarbons / Q000737:chemistry* / Q000493:pharmacokinetics*; D007668:Kidney / Q000098:blood supply* / Q000000981:diagnostic imaging*; D007700:Kinetics; D045423:Microbubbles; D044367:Phase Transition; D051381:Rats; D011916:Rats, Inbred F344; D014159:Transducers; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media; D005466:Fluorocarbons
keywords: Acoustic droplet vaporization; Contrast agent; Microbubble; Perfluorobutane; Perfluoropropane; Phase change; Ultrasound