The role of both inertial and stable cavitation was investigated during in vitro ultrasound-accelerated fibrinolysis by recombinant tissue plasminogen activator (rt-PA) in the presence and absence of Optison. A unique treatment configuration applied ultrasound, rt-PA and Optison to the interior of a plasma clot. Lysis efficacy was measured as clot weight reduction. Cavitational mechanisms were investigated by monitoring subharmonic and broadband noise. In the absence of Optison, 1.7 MHz pulsed ultrasound with 1.5 MPa peak-negative pressure applied for 30 min resulted in 45 +/- 19% lysis enhancement relative to rt-PA alone. Cavitation was not detected, indicating a role of noncavitational effects of ultrasound. The addition of Optison increased lysis enhancement to 88 +/- 25%. Inertial cavitation was present only at the start of the exposure, while low-amplitude subharmonic emissions persisted throughout. Additional protocols suggested a possible correlation between the increased lysis in the presence of Optison and the subharmonic emission, indicating a potentially important role of stable rather than inertial cavitation in microbubble-enhanced ultrasound-accelerated rt-PA-mediated thrombolysis.
High-intensity focused ultrasound appears to provide long-lasting hemostasis of acute liver injury. Healing and repair mechanisms after high-intensity focused ultrasound application appear to be intact.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.