Medical Probe Tissue Thickness Estimation Using Force and Position Sensors
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Solution Overview
Problem
Current medical procedures face challenges in accurately estimating tissue thickness during invasive procedures, as existing methods lack precision in determining the thickness of body cavity walls using contact force and location measurements, which can lead to complications like tissue perforation or inefficiency in ablation procedures.
Innovation Solution
A method and system that utilize a medical probe equipped with both a force sensor and a position sensor to measure the force exerted by the probe's distal end on a body cavity wall and the resulting displacement, with calibration matrices initialized for different types of tissue to estimate wall thickness, allowing for interpolation when exact values are not available.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contact force measurements alone are used to estimate tissue thickness, then the measurement process is simple, but the estimation precision is insufficient
Solution Approach 1:
The patent combines force sensor measurements with position sensor measurements into a unified tissue thickness estimation system. By merging data from both sensors and processing them together through calibration matrices, the system achieves more accurate thickness estimation than either sensor could provide alone, while maintaining a integrated rather than separate measurement approach.
Solution Approach 2:
The patent introduces calibration matrices as an intermediary element that translates raw force and position measurements into accurate tissue thickness estimates. These calibration matrices serve as a mediator between the sensor data and the final thickness measurement, enabling precise estimation without requiring direct physical measurement of tissue thickness.
2Measurement precision
If force sensor is added to measure contact force, then tissue thickness estimation accuracy improves, but device complexity increases
Solution Approach 1:
The probe is designed with multi-functionality, where the distal end structure serves multiple purposes: it provides mechanical contact with the tissue for force measurement, maintains positional tracking capability, and delivers therapeutic energy. This universal design allows a single structure to fulfill multiple functions, reducing the need for separate specialized components.
Solution Approach 2:
The force sensor is integrated within the distal end structure of the probe, with the sensor embedded in the catheter wall or tip assembly. This nested arrangement allows the force measurement capability to be incorporated within the existing probe structure without requiring a completely separate measurement device, thereby minimizing additional complexity.
3Measurement precision
If position sensor and force sensor are both used, then tissue thickness measurement accuracy improves, but the cost of the probe increases
Solution Approach 1:
The patent implements preliminary calibration procedures where calibration matrices are pre-computed and stored before actual use. During manufacturing and setup, the probe characteristics are calibrated against known tissue properties, and these calibration data are stored for later use. This preliminary action eliminates the need for complex real-time calculations during procedures, reducing computational hardware requirements and associated costs.
Solution Approach 2:
The patent uses calibration matrices that represent idealized models of tissue-probe interactions. Instead of requiring expensive real-time measurement and calculation systems, the system uses pre-computed calibration data that copies the essential characteristics of tissue mechanical properties. This allows accurate thickness estimation through lookup and interpolation in calibration tables rather than through complex real-time physical modeling.
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
Enables precise estimation of tissue thickness, reducing the risk of perforation and improving the efficiency of procedures like cardiac ablation by accurately determining the force required for thin or thick tissues, potentially replacing or complementing imaging methods like MRI or CT.
Implementation Method 1
a force sensor in the distal end, configured to generate a first signal indicative of a force exerted by the distal end on the wall
Implementation Method 2
Magnetic position sensing is one of the methods known in the art. In magnetic position sensing, magnetic field generators are typically placed at known positions external to the patient. A magnetic field sensor within the distal end of a probe generates electrical signals in response to these magnetic fields
Implementation Method 3
receiving second measurements indicating a displacement of the wall in response to the force
Data Source
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AI summary
A method, including pressing a distal end of a medical probe against a wall of a body cavity, and receiving from the probe first measurements of a force exerted by the distal end on the wall. The method also includes receiving from the probe second measurements indicating a displacement of the wall in response to the force. The method further includes estimating a thickness of the wall based on the first and the second measurements.