Electrode Contact Detection Using Baseline and Peak Impedance
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Solution Overview
Problem
Existing methods for determining contact between electrodes and adjacent tissue using impedance measurements are unreliable due to variations caused by factors such as electrode location and tissue movement, making it difficult to accurately assess contact status.
Innovation Solution
The method involves applying drive signals between electrode pairs, measuring bipolar electrode complex impedance (BECI) values, determining a baseline BECI value, and using a combination of peak-to-peak and baseline BECI values to determine contact status, which includes displaying proximity or contact states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If raw electrode impedance measurements are used to determine contact status, then the measurement process is simple, but the reliability of contact detection is poor due to variations from electrode location and tissue movement
Solution Approach 1:
The system performs preliminary actions by measuring impedance over a collection period before actual contact determination, establishing a baseline impedance value that accounts for location variations and tissue movement. This preliminary measurement phase allows the system to characterize the electrode-tissue interface under current conditions before making contact status decisions.
Solution Approach 2:
The system employs periodic action by continuously measuring impedance values over time intervals, comparing current measurements against baseline values established during collection periods. This periodic measurement and comparison approach enables the system to distinguish between impedance variations due to tissue movement and those indicating actual contact status changes.
2Measurement precision
If impedance measurements are taken continuously to account for tissue movement and location variations, then contact detection accuracy improves, but the complexity of processing multiple impedance values increases
Solution Approach 1:
The system performs preliminary impedance measurements during a collection period to establish a baseline value that captures the electrode's electrical characteristics at its current location and tissue interaction state. This baseline serves as a reference for subsequent contact determination, simplifying the processing of ongoing measurements.
Solution Approach 2:
The system uses feedback by comparing current impedance measurements against the established baseline value. When the current measurement deviates from the baseline beyond a threshold, the system determines a contact status change. This feedback mechanism enables precise contact detection while maintaining manageable processing complexity through systematic comparison logic.
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 a more robust and accurate determination of electrode contact status by accounting for variations in impedance, ensuring reliable detection of contact and proximity to tissue.
Implementation Method 1
measuring a bipolar electrode complex impedance (BECI) value generated in response to the drive signals
Data Source
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AI summary
A method of determining contact status of electrodes includes applying drive signals between pairs of electrodes, measuring a bipolar electrode complex impedance (BECI) value generated in response to the drive signals over a collection period, and determining a baseline BECI value representing a minimum value measured during the collection period. The method further includes determining contact status of the electrode by applying drive signals between pairs of electrodes over a given interval, measuring a BECI value generated in response to the drive signals, measuring a peak-to-peak value associated with the BECI values measured over the given interval, and determining contact status based on a combination of the baseline BECI value, the measured BECI value, and the peak-to-peak value associated with the measured BECI values.