Megahertz rate, volumetric imaging of bubble clouds in sonothrombolysis using a sparse hemispherical receiver array.

Area of Science:

• Medical Imaging
• Ultrasound Technology
• Cardiovascular Interventions

Background:

• High-intensity focused ultrasound (HIFU) shows promise for non-invasive clot dissolution in cardiovascular diseases like deep vein thrombosis (DVT).
• A significant limitation to HIFU adoption for sonothrombolysis is the absence of effective real-time treatment monitoring tools.

Purpose of the Study:

• To investigate the feasibility of using cavitation imaging for monitoring clot degradation during sonothrombolysis.
• To assess the speed and resolution of cavitation imaging for in vivo applications.

Main Methods:

• Cavitation imaging was performed using a large-aperture, sparse hemispherical receiver array during sonothrombolysis.
• Multi-cycle burst exposures at 1.51 MHz with varying burst lengths (0.1 or 1 ms) were employed.
• Clot degradation was subsequently assessed using 30 MHz ultrasound.

Main Results:

• Bubble cloud generation observed via cavitation imaging directly correlated with areas of clot degradation.
• 3D cavitation imaging achieved integration times as short as 1 µs, enabling visualization of cavitation dynamics.
• The imaging technique demonstrated megahertz frame rates, significantly exceeding current in vivo imaging capabilities.

Conclusions:

• Cavitation imaging effectively visualizes clot degradation during sonothrombolysis.
• The high speed and resolution of this imaging method offer a potential solution for real-time monitoring of DVT treatments.
• Integrating bubble activity imaging receivers into future DVT therapy devices is recommended.