Catheter Contact Force Estimation via Electromagnetic Signal Deformation
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Solution Overview
Problem
Existing catheter systems face challenges in accurately measuring and estimating contact force between medical devices and tissue, particularly due to the complexity and flexibility of components like piezoelectric crystals, which can lead to insufficient accuracy in procedures such as RF ablation.
Innovation Solution
A catheter system with an expandable distal-end assembly (EDEA) equipped with a transmitter and receivers, where the transmitter is coupled to a rigid component and receivers to elastic components like splines or a balloon, uses electrical signals to estimate contact force by quantifying deformation through a calibration dataset, improving accuracy and reducing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If piezoelectric crystals are used to measure contact force, then measurement capability is provided, but measurement precision is insufficient and device complexity increases
Solution Approach 1:
The patent replaces mechanical piezoelectric crystal sensors with an electromagnetic field-based measurement system. A transmitter generates electromagnetic signals that are received by receivers at different locations on the catheter shaft. The contact force is determined by analyzing changes in electromagnetic signal characteristics (phase, amplitude, or frequency) caused by shaft deformation, eliminating the need for complex mechanical sensors and improving measurement reliability.
Solution Approach 2:
The patent introduces electromagnetic fields as an intermediary to indirectly measure contact force. Instead of directly measuring force with crystals, the system measures electromagnetic signal variations that result from force-induced shaft deformation. This intermediary approach allows force measurement without direct mechanical contact sensors, reducing device complexity while maintaining measurement capability.
2Adaptability or versatility
If flexible components are used to conform to tissue, then adaptability improves, but measurement accuracy deteriorates due to component flexibility
Solution Approach 1:
The patent replaces direct mechanical force sensing with electromagnetic field sensing. The flexible shaft's deformation under tissue contact is detected through changes in electromagnetic signal phase, amplitude, or frequency between transmitter and receiver. This substitution allows the shaft to remain flexible for tissue conformability while achieving accurate force measurement through field-based sensing rather than mechanical sensors.
Solution Approach 2:
The system uses feedback from electromagnetic signal characteristics to determine contact force. The transmitter continuously emits signals and the receiver provides feedback on signal variations caused by shaft deformation. This feedback mechanism enables real-time contact force estimation while maintaining shaft flexibility, as the electromagnetic field responds to mechanical deformation without being constrained by rigid sensor structures.
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 enhances the precision of RF ablation procedures by accurately estimating contact force, ensuring proper tissue ablation with specified lesion properties, and is applicable to other medical procedures requiring accurate contact force sensing.
Implementation Method 1
a transmitter, which is coupled to the EDEA and is configured to transmit a first signal, and (ii) one or more receivers, which are coupled to an elastic component of the EDEA, and are configured to produce one or more respective second signals in response to receiving the first signal
Data Source
Figure 1
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AI summary
A system includes a catheter and a processor. The catheter includes an expandable distal-end assembly (EDEA) having: (i) a transmitter, which is coupled to the EDEA and is configured to transmit a first signal, and (ii) one or more receivers, which are coupled to an elastic component of the EDEA, and are configured to produce one or more respective second signals in response to receiving the first signal. The processor is configured to estimate, based on the one or more respective second signals, a force applied to the elastic component.