Adaptive Pulsing Sonothrombolysis for Heat and Microbubble Control
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Solution Overview
Problem
Sonothrombolysis treatments for ischemic stroke face limitations due to heat generation at the ultrasound transducer/skull interface and excessive microbubble destruction, which can reduce treatment effectiveness and feasibility.
Innovation Solution
An adaptive ultrasound pulsing system that adjusts pulse parameters based on echo signatures from microbubbles within the treatment region to minimize heat and microbubble destruction, optimizing microbubble concentration and cavitation at the occlusion site.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultrasound pulse intensity and duration are increased to improve clot lysis effectiveness, then treatment efficacy is improved, but heat generation at the transducer/skull interface increases excessively
Solution Approach 1:
The patent applies periodic pulsed ultrasound instead of continuous ultrasound, using duty cycles where pulses are delivered intermittently (e.g., 10ms pulses with 90ms intervals). This periodic action allows thermal dissipation between pulses, reducing cumulative heat generation at the transducer-skull interface while maintaining effective mechanical cavitation at the clot site during the pulse windows.
Solution Approach 2:
The patent dynamically adjusts ultrasound pulse parameters (intensity, duration, duty cycle) based on real-time monitoring of microbubble echo signatures and temperature feedback. The system adapts pulse characteristics during treatment to maintain optimal clot lysis effectiveness while preventing excessive heat buildup, transitioning from static to dynamic parameter control.
2Reliability
If ultrasound pulse energy is increased to enhance microbubble oscillation and clot dissolution, then treatment effectiveness is improved, but microbubble destruction occurs excessively
Solution Approach 1:
The patent implements feedback control by monitoring echo signatures from microbubbles in real-time. The system analyzes changes in echo intensity and characteristics to detect microbubble oscillation states and destruction levels. Based on this feedback, the controller dynamically adjusts subsequent pulse parameters to maintain effective cavitation at the clot while preventing excessive microbubble destruction in the bloodstream.
Solution Approach 2:
The patent creates different local conditions for microbubbles at different locations: high-intensity focused ultrasound at the clot site produces strong cavitation for effective clot dissolution, while lower intensity in surrounding vascular regions preserves microbubbles for continued treatment. This spatial differentiation of ultrasound intensity achieves local quality optimization.
3Power
If the focal zone is kept stationary to maximize energy concentration, then microbubble excitation at the target is improved, but the treatment region coverage is insufficient
Solution Approach 1:
The patent divides the treatment into multiple focal zones that are sequentially activated. Instead of one stationary focus, the system segments the target volume into multiple regions and delivers focused ultrasound to each segment in sequence, ensuring comprehensive coverage of the entire clot while maintaining high energy concentration at each focal point during its activation window.
Solution Approach 2:
The patent makes the focal zone dynamic by moving it through the treatment region using phased array beam steering or mechanical transducer movement. The focal point transitions between multiple positions to cover the entire clot volume, transforming from a static single-point focus to a dynamic multi-point coverage strategy that maintains energy concentration while expanding treatment area.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively removes occlusions by minimizing heat generation and microbubble destruction, enhancing the concentration of microbubbles at the clot site, thereby improving the efficacy of sonothrombolysis treatments.
Implementation Method 1
ultrasound pulses may often be delivered through the skull temporal bone of a patient, targeting microbubbles congregating at the clot site
Implementation Method 2
Energy received from the ultrasound pulses may cause mechanical oscillation of the microbubbles at the site of the clot
Implementation Method 3
Ultrasound echoes reflected from the microbubbles present within this region may then be received by a transducer
Implementation Method 4
Echo signatures identified by processing the received echoes may reveal information about the microbubbles and/or the occlusion present at the treatment region
Implementation Method 5
the heat generated by the ultrasound transducer during such sonothrombolysis treatments often limits its feasibility and effectiveness
Implementation Method 6
Energy received from the ultrasound pulses may cause mechanical oscillation of the microbubbles... thus recanalizing the occluded vessel(s)
Data Source
AI summary
A therapeutic ultrasound method configured to adaptively transmit ultrasound pulses toward microbubbles in a treatment region to remove an occlusion is described. In some examples, the system may include a treatment pulse unit configured to transmit an ultrasound pulse to a treatment region of a subject, the treatment region including a plurality of microbubbles. An echo detection unit may be configured to receive one or more echoes responsive to the ultrasound pulse. In some examples, the method may also include a data processor configured to identify, using data associated with the echoes, at least one echo signature indicative of a dynamic state of the microbubbles in response to the ultrasound pulse. A controller may be configured to adjust one or more parameters of an additional ultrasound pulse transmitted to the treatment region via the treatment pulse unit based on the at least one echo signature.