Dual-Frequency Intravascular Sonothrombolysis for Retracted Clots

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Solution Overview

Problem

Current sonothrombolysis methods, including external ultrasound and intravascular transducers, face challenges in effectively treating both unretracted and retracted blood clots due to limited pressure output, tissue damage risks, and inefficiencies in covering a large enough frequency range, especially for completely occluded clots.

Innovation Solution

A forward-viewing ultrasound transducer integrated into a catheter delivers dual-frequency ultrasound excitation, using microbubbles and nanodroplets, to reduce cavitation threshold and enhance clot lysis, with adjustable frequency components and power levels for safe and efficient thrombolysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If external ultrasound is used for sonothrombolysis, then treatment coverage is improved, but tissue damage risk increases and treatment time extends

Engineering Contradiction:

Improvetreatment coverageVSAvoidtissue damage risk

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intravascular transducer as an intermediary device positioned within the blood vessel to deliver ultrasound energy directly to the clot. This mediator approach allows focused energy delivery to the target (clot) while minimizing exposure to surrounding healthy tissues, thereby reducing tissue damage risk while maintaining effective treatment coverage

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical external ultrasound system with an intravascular transducer system that delivers energy through the blood vessel lumen. This substitution enables more precise energy localization and reduces the need for high-power external ultrasound that causes tissue damage and extended treatment times

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If intravascular transducer with single frequency is used, then device simplicity is improved, but treatment effectiveness for retracted clots deteriorates

Engineering Contradiction:

Improvedevice simplicityVSAvoidtreatment effectiveness

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent implements a dual-frequency transducer system that dynamically switches between or combines two frequency components. This dynamic approach allows the device to adapt to different clot types (unretracted and retracted) by optimizing frequency selection, thereby improving treatment effectiveness without significantly increasing device complexity

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the ultrasound frequency parameter from a single fixed frequency to a dual-frequency system. This parameter modification enables the transducer to effectively treat both unretracted and retracted clots by utilizing the complementary cavitation effects of different frequencies, significantly improving treatment reliability

Inventive Principle:

Principle #35Parameter changes

3Productivity

If high ultrasound power is applied to generate cavitation, then clot lysis effectiveness is improved, but vessel wall damage risk increases

Engineering Contradiction:

Improveclot lysis effectivenessVSAvoidvessel wall damage risk

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies ultrasound energy locally at the clot site using an intravascular transducer positioned within the vessel. This localized energy delivery generates cavitation effects specifically at the clot interface while minimizing energy exposure to the vessel wall, thereby maintaining high clot lysis effectiveness while reducing vessel wall damage risk

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses contrast agents (microbubbles or nanodroplets) as intermediaries to enhance cavitation effects at the clot surface. These agents amplify the ultrasound energy conversion to mechanical effects locally at the clot, improving lysis effectiveness without requiring high power that would damage the vessel wall

Inventive Principle:

Principle #24Intermediary (Mediator)

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 dual-frequency approach significantly improves clot lysis rates by increasing cavitation efficiency and reducing treatment time, offering safer and more effective deep vein thrombolysis for both unretracted and retracted clots compared to single-frequency methods.

Implementation Method 1

The primary mechanism is that MBs can generate stable and inertial cavitation under ultrasound excitation, which induces microstreaming and microjets for breaking the structure of the blood clots

Methodology Applied

Scientific EffectAcoustic cavitation: Acoustic Cavitation

Data Source

PatentUS20260033848A1Intravascular dual frequency sonothrombolysis mediated with microbubbles/nanodroplets

Publication Date: 2026.02.05 NORTH CAROLINA STATE UNIV

AI summary

A method for sonothrombolysis mediated with contrast agents includes administering at least one contrast agent into a blood vessel of a patient. The method further includes controlling application of ultrasound energy to the at least one contrast agent within the blood vessel, wherein controlling the application of the ultrasound energy includes driving an ultrasound transducer with a signal having a first frequency component and a second frequency component different from the first frequency component.