Impedance Navigation Drift Correction via Magnetic Mapping
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Solution Overview
Problem
Electric field-based medical device navigation systems are prone to errors due to drift and shift in patient impedance levels, which existing methods like bio-impedance scaling and patch center subtraction do not fully address, and the use of a fixed reference catheter increases procedure time and risk.
Innovation Solution
A system and method that utilize both electric field and magnetic field-based positioning systems, with an electronic control unit applying a mapping function to correlate the positions of electrical and magnetic position sensors, allowing for accurate adjustment of the electrical position sensor's position without the need for an additional reference catheter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed reference catheter is used to correct impedance drift and shift, then position measurement accuracy is improved, but procedure time increases and risk of complications increases
Solution Approach 1:
The patent extracts the reference function from a physical reference catheter and implements it through software algorithms. The system uses electrical position sensors on the medical device itself to generate reference positions through mathematical calculations, eliminating the need for a separate physical reference catheter while maintaining position measurement accuracy.
Solution Approach 2:
The patent introduces mathematical algorithms and coordinate system transformations as intermediaries between the electrical position sensors and the final position measurements. These computational intermediaries enable drift and shift correction without requiring additional physical hardware, thus reducing procedure time and complications.
2Measurement precision
If a fixed reference catheter is used to correct impedance drift and shift, then position measurement accuracy is improved, but device complexity and risk of complications increase
Solution Approach 1:
The patent removes the need for a physical reference catheter by extracting the reference functionality into the navigation system's software. Electrical position sensors on the medical device itself are used with mathematical algorithms to generate reference positions, simplifying the overall system while maintaining measurement accuracy.
Solution Approach 2:
The medical device performs its own position measurement and drift correction using its own electrical position sensors. The system uses self-generated reference positions through mathematical calculations, eliminating the need for external reference hardware and reducing system complexity.
3Measurement precision
If bio-impedance scaling and patch center subtraction are used to reduce drift and shift, then position measurement accuracy is partially improved, but not all cases of drift and shift are eliminated
Solution Approach 1:
The patent changes the approach from modifying impedance measurements to transforming coordinate systems. By applying mathematical transformations that account for drift and shift parameters, the system achieves more consistent and reliable correction across all cases, rather than partially reducing errors through impedance scaling.
Solution Approach 2:
The system performs preliminary calculations to generate accurate reference positions before final position determination. By pre-computing reference positions using electrical position sensors and mathematical algorithms, the system establishes a reliable baseline for correction that addresses all drift and shift cases consistently.
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 consistently corrects for errors caused by impedance drift and shift, enhancing navigation accuracy without increasing procedure time or risk, and eliminates the need for an additional reference catheter.
Implementation Method 1
The system is based on the principle that when electrical currents are passed through the thorax a voltage drop occurs across internal organs such as the heart and this voltage drop can be measured and used to determine the position of a medical device within the body
Implementation Method 2
determining an operating position for a magnetic position sensor on the medical device within a second coordinate system defined by a magnetic field based positioning system
Data Source
AI summary
A system and method for navigating a medical device within a body are provided. The system includes an electronic control unit configured to determine operating positions for electrical and magnetic position sensors on the medical device within corresponding first and second coordinate systems. The first and second coordinate systems are defined by an electric field based positioning system and a magnetic field based positioning system, respectively. The magnetic position sensor is disposed proximate the electrical position sensor. The ECU is further configured to apply a mapping function correlating the operating positions which generates a mapped position for the magnetic position sensor in the first coordinate system responsive to the operating position of the magnetic position sensor in the second coordinate system. The ECU determines an adjusted operating position for the electrical position sensor in the first coordinate system responsive to the mapped position of the magnetic position sensor.