3D Ice Ball Modeling for Cryoablation Monitoring
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Solution Overview
Problem
Current cryoablation procedures face challenges in accurately determining the size, shape, and location of the ice ball formed during tissue freezing, which can lead to unnecessary damage to healthy tissue or incomplete ablation of targeted tissue.
Innovation Solution
The method involves using a linear endobronchial ultrasound (EBUS) device to image the targeted tissue and guide a cryoprobe, while creating a 3D model of the ice ball by combining visible and hidden surface points, and presenting this information in real-time to the practitioner through a user interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasound energy is emitted to image the ice ball, then the visible portion of the ice ball can be detected, but the ultrasound energy cannot pass beyond the peripheral surface of the ice ball due to impedance mismatch, making the hidden portion undetectable
Solution Approach 1:
The patent creates a virtual 3D copy of the ice ball by mathematically mirroring the detected visible surface points across the cryoprobe axis. This virtual model replicates the hidden portions of the ice ball that cannot be directly detected by ultrasound, allowing practitioners to visualize the complete ice ball geometry including the acoustic shadow region.
Solution Approach 2:
The patent transitions from 2D ultrasound image slices to a 3D virtual model of the ice ball. By combining multiple 2D slices and applying mathematical mirroring operations, the system reconstructs the third dimension and creates a comprehensive 3D representation that overcomes the limitations of 2D imaging through acoustic shadowing.
2Loss of information
If multiple image slices are combined to create a 3D model of the ice ball, then the relationship between the ice ball and targeted tissue can be visualized, but the acoustic shadowing prevents direct observation of the complete ice ball structure
Solution Approach 1:
The patent replaces direct mechanical/optical observation of the ice ball with a computational modeling approach. Instead of attempting to physically penetrate the acoustic shadow or use more complex imaging hardware, the system uses mathematical algorithms to predict and render the hidden portions of the ice ball based on the detected visible surface geometry.
3Reliability
If the ice ball is made larger to ensure complete ablation of targeted tissue, then all abnormal tissue can be destroyed, but healthy tissue surrounding the target tissue will be unnecessarily damaged
Solution Approach 1:
The patent implements real-time feedback by continuously updating the virtual 3D ice ball model during the cryoablation procedure. The system compares the modeled ice ball boundaries with the pre-planned treatment zone and provides immediate visual feedback to the practitioner, allowing for real-time adjustments to freezing parameters to achieve complete ablation while minimizing damage to healthy tissue.
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
This approach allows for precise monitoring of the ice ball formation and its relationship to the targeted tissue, enabling the practitioner to adjust the freezing process to ensure effective ablation while minimizing damage to surrounding tissue.
Implementation Method 1
a linear endobronchial ultrasound (EBUS) device is positioned in the trachea-bronchial tree of the patient adjacent the targeted tissue. The EBUS will then image the targeted tissue
Implementation Method 2
Because of the impedance mismatch that results from the nature of the ice ball relative to the surrounding unfrozen tissues, the ultrasound energy that is emitted from the EBUS device may be unable to pass beyond the peripheral surface (or perimeter) of the ice ball
Implementation Method 3
The freezing of tissue cells causes the cells or organelles within the cells to rupture. The cryosurgery process typically involves the insertion of a device (a 'cryoprobe') into the abnormal tissue and then cooling the device. In most circumstances, the cooling of the cryoprobe is accomplished by passing a high-pressure gas, such as argon, through the device. The cooling of the cryoprobe in this manner creates an 'ice ball' of frozen tissue
Data Source
AI summary
A system and method are presented for treating targeted tissue using cryoablation. A linear endobronchial ultrasound (EBUS) device is positioned adjacent the targeted tissue and is used to guide a percutaneously inserted cryoprobe into the targeted tissue. The EBUS device is partially rotated in order to create multiple image slices that are combined together. To overcome the acoustic shadow created by the ice ball, a 3D model is created of the ice ball based on the locations identified on visible portion of the ice ball's peripheral surface. These locations are mirrored across an axis defined for the cryoprobe to define an approximate location for the hidden, non-visible periphery. This model is then displayed along with the location of the targeted tissue and an indication of the killing zone of the ice ball defined by a selected isotherm.