Impedance Shift Detection via Magnetic Reference Sensor
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Solution Overview
Problem
Impedance-based localization systems in medical devices are susceptible to shifts and drift due to inhomogeneities in the electrical field and external factors, leading to inaccuracies in tracking catheters and other medical devices within the body, while magnetic-based systems are limited by the number of localization elements that can be simultaneously tracked.
Innovation Solution
A method that combines impedance and magnetic-based localization systems by registering the impedance-based coordinate system with the magnetic-based coordinate system to detect and correct impedance shifts, using electromagnetic registrations to transform and correct the impedance locations of electrodes, allowing for accurate navigation comparable to magnetic-based systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If an impedance-based localization system is used, then the ability to track numerous localization elements simultaneously is improved, but measurement precision deteriorates due to inhomogeneities in the electrical field and shift and drift
Solution Approach 1:
A magnetic position sensor is introduced as an intermediary reference element that is tracked by both the impedance-based system and the magnetic-based system. This intermediary allows for real-time detection of impedance shifts by comparing the coordinate discrepancies, enabling correction of the impedance system's measurements while maintaining the ability to track multiple localization elements.
Solution Approach 2:
The system continuously monitors the difference between impedance-based coordinates and magnetic-based coordinates of the reference element, using this feedback to detect impedance shifts. When a shift is detected, the system applies correction transformations to the impedance coordinates, creating a closed-loop control that maintains measurement precision throughout the procedure.
2Measurement precision
If a magnetic-based system is used, then measurement precision is improved with improved homogeneity and less drift, but device complexity increases due to special sensors required as localization elements
Solution Approach 1:
Instead of requiring all localization elements to be complex magnetic sensors, the system uses a single magnetic position sensor as a reference intermediary. The majority of localization elements can remain simple electrodes, while the magnetic sensor provides the stable reference needed for correction, significantly reducing overall device complexity.
Solution Approach 2:
The system creates a virtual copy of the magnetic-based coordinate system within the impedance-based system by continuously transforming and applying magnetic coordinates as correction references. This allows the impedance system to achieve magnetic-level precision without requiring magnetic sensors for all localization elements.
3Ease of operation
If impedance-based localization is used, then ease of operation is improved with ubiquitous impedance devices, but reliability deteriorates due to shift and drift from varying impedance regions
Solution Approach 1:
The system implements continuous feedback monitoring by comparing impedance-based coordinates with magnetic-based coordinates of a reference element. When impedance shifts are detected through this feedback mechanism, automatic correction transformations are applied, ensuring reliable and stable coordinate tracking throughout the entire procedure.
Solution Approach 2:
The system performs preliminary transformation and correction of impedance coordinates by establishing an electromagnetic registration between the impedance-based coordinate system and the magnetic-based coordinate system before the procedure begins. This preliminary setup enables real-time detection and correction of impedance shifts, ensuring reliable coordinate stability throughout the procedure.
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 enables time-independent detection and correction of impedance shifts and drift, improving the accuracy of impedance-based navigation systems by leveraging the stability of magnetic-based systems, while allowing for the tracking of multiple localization elements, thus enhancing the precision and ubiquity of impedance-based devices.
Implementation Method 1
a magnetic location of a magnetic position sensor in a magnetic based coordinate system is received
Implementation Method 2
an impedance location of an electrode in an impedance based coordinate system is received
Data Source
AI summary
An impedance location of an electrode in an impedance based coordinate system and a magnetic location of a magnetic position sensor in a magnetic based coordinate system can be received. A transformed impedance location of the magnetic position sensor can be computed. A difference between the transformed impedance location of the magnetic position sensor and the magnetic location of the magnetic position sensor can be determined. A magnitude of the difference between the impedance location of the magnetic position sensor and the magnetic location of the magnetic position sensor can be computed. A statistical significance of the difference between the transformed impedance location of the magnetic position sensor and the magnetic location of the magnetic position sensor can be computed. A determination can be made that an impedance shift exists if the magnitude of the difference exceeds a threshold and a statistical significance of the difference exceeds a threshold.