title: High-intensity focused ultrasound sonothrombolysis: the use of perfluorocarbon droplets to achieve clot lysis at reduced acoustic power.
abstract: The purpose of this study was to evaluate use of intravascular perfluorocarbon droplets to reduce the sonication power required to achieve clot lysis with high-intensity focused ultrasound. High-intensity focused ultrasound with droplets was initially applied to blood clots in an in vitro flow apparatus, and inertial cavitation thresholds were determined. An embolic model for ischemic stroke was used to illustrate the feasibility of this technique in vivo. Recanalization with intravascular droplets was achieved in vivo at 24 ± 5% of the sonication power without droplets. Recanalization occurred in 71% of rabbits that received 1-ms pulsed sonications during continuous intravascular droplet infusion (p = 0.041 vs controls). Preliminary experiments indicated that damage was confined to the ultrasonic focus, suggesting that tolerable treatments would be possible with a more tightly focused hemispheric array that allows the whole focus to be placed inside of the main arteries in the human brain.
authors.affiliation: Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Canada. Electronic address: dpajek@sri.utoronto.ca.
authors.forename: Daniel
authors.initials: D
authors.lastname: Pajek
authors.affiliation: Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Canada.
authors.forename: Alison
authors.initials: A
authors.lastname: Burgess
authors.affiliation: Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Canada.
authors.forename: Yuexi
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Canada.
authors.forename: Kullervo
authors.initials: K
authors.lastname: Hynynen
mesh_terms: D000162:Acoustics; D000818:Animals; D004195:Disease Models, Animal; D005466:Fluorocarbons / Q000494:pharmacology*; D057086:High-Intensity Focused Ultrasound Ablation / Q000379:methods*; D008297:Male; D011817:Rabbits; D020521:Stroke / Q000000981:diagnostic imaging*; D015912:Thrombolytic Therapy / Q000379:methods*; D013927:Thrombosis / Q000628:therapy*; D014463:Ultrasonography
chemical_list: D005466:Fluorocarbons
keywords: Focused ultrasound; High-intensity focused ultrasound; Inertial cavitation; Sonothrombolysis; Stroke