Impedance Navigation Drift Correction via Magnetic Mapping
Find Innovative SolutionsGenerate Solutions
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 combine electric and magnetic field-based positioning systems, using an electronic control unit to determine positions for both types of sensors and apply mapping functions to correct for impedance changes without requiring 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 uses magnetic field position measurements as a copy or reference framework to correct the electric field position measurements. Instead of using a physical reference catheter, the system creates a virtual reference based on magnetic field data, which is then used to adjust and correct the impedance-based position measurements throughout the procedure.
Solution Approach 2:
The patent replaces the mechanical reference catheter system with a magnetic field-based positioning system. The magnetic sensors and field generation system substitute for the physical reference catheter, eliminating the need for additional invasive hardware while providing continuous position correction capability.
2Measurement precision
If a fixed reference catheter is used to correct impedance drift and shift, then position measurement accuracy is improved, but risk of complications increases
Solution Approach 1:
The magnetic field position data serves as a non-invasive copy or proxy for the reference framework, eliminating the need to physically insert an additional catheter into the patient's body, thereby reducing procedural risks while maintaining correction capability.
Solution Approach 2:
The magnetic field-based system replaces the mechanical reference catheter, eliminating risks associated with catheter insertion such as vessel perforation, thrombus formation, or catheter dislodgement, while providing continuous position correction.
3Measurement precision
If bio-impedance scaling and patch center subtraction are used to reduce drift and shift, then some correction is achieved, but all cases of drift and shift are not eliminated
Solution Approach 1:
The magnetic field positioning system acts as an intermediary reference framework that mediates between the electric field measurements and the patient's changing impedance conditions. It provides an impedance-independent reference that corrects the electric field measurements, overcoming the limitations of pure bio-impedance scaling methods.
Solution Approach 2:
The system changes the reference parameter from impedance-based (which varies with patient condition) to magnetic field-based (which remains stable). By using magnetic field position as the reference parameter, the system achieves more complete and reliable correction of drift and shift across all cases.
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 provides consistent correction of position measurement errors due to impedance changes, reducing variability and eliminating the need for an additional reference catheter, thereby minimizing procedure time and risks.
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
determine an operating position for a magnetic position sensor on the medical device within a second coordinate system. The second coordinate system is defined by a magnetic field based positioning system
Data Source
Figure 1
Figure 2
Figure 3A
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.