Phase Multiplexed Electrical Impedance Tomography for Nerve Activity Imaging
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Solution Overview
Problem
Current methods for detecting electrical activity in peripheral nerves are not fast enough to image a single action potential event effectively, as they require longer acquisition times and do not adequately capture the rapid changes in impedance during nerve activity.
Innovation Solution
The use of phase multiplexed and/or frequency multiplexed electrical impedance tomography, where multiple probe electrical signals of different phases and frequencies are applied simultaneously to multiple electrode combinations, allowing for faster data acquisition and improved time resolution in imaging nerve activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electrical impedance tomography methods are used to image peripheral nerve activity, then measurement precision can be maintained, but the acquisition time is too long to capture single action potential events
Solution Approach 1:
The patent segments the measurement process by dividing it into multiple phase channels (e.g., in-phase and quadrature-phase measurements). Multiple probe signals with different phases are applied simultaneously to different electrode combinations, allowing parallel acquisition of multiple measurement sets. This segmentation enables the system to capture sufficient data for image reconstruction within the brief duration of a single action potential event, resolving the contradiction between measurement precision and acquisition time.
Solution Approach 2:
The patent implements continuous multiplexed measurement where multiple phase channels operate simultaneously and continuously during the nerve action potential event. Rather than sequentially acquiring data over an extended period, the system maintains continuous useful action by applying multiple phase-separated probe signals in parallel, ensuring that the entire action potential waveform is captured within its natural brief time window while maintaining imaging precision.
2Productivity
If multiple probe electrical signals are applied simultaneously to multiple electrode combinations, then the rate of interrogation is doubled and acquisition time is halved, but the device complexity increases
Solution Approach 1:
The patent employs periodic action by applying probe signals with specific phase relationships (e.g., 0° and 90° phases) in a structured, repeating pattern. This periodic modulation allows the system to encode multiple measurement channels in a systematic way that can be efficiently processed. The phase-separated periodic signals enable doubled interrogation rates while managing device complexity through predictable, repeating measurement cycles that simplify synchronization and data processing.
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 the acquisition of a single frame or image of a nerve cross-section in a few milliseconds, doubling the rate of interrogation or halving the data acquisition time, providing detailed electrical property maps of peripheral nerves with enhanced time resolution.
Implementation Method 1
simultaneously applying a phase separated pair of first and second probe electrical signals to a set of respective first and second combinations of electrodes
Implementation Method 2
detecting a pair of phase separated electrical responses corresponding to the different signal phases from the one or more combined responses, and using the pair of phase separated electrical responses to determine electrical properties
Data Source
AI summary
There are disclosed methods and apparatus for determining electrical properties in a peripheral nerve of a human or animal subject. A plurality of electrodes are spaced around a perimeter of the peripheral nerve, and a phase separated pair of first and second probe electrical signals are applied simultaneously to a set of respective first and second combinations of electrodes, the phase separated pair of first and second probe electrical signals having different signal phases from each other. One or more combined responses to the phase separated pair are collected at one or more of the plurality of electrodes, and a pair of phase separated electrical responses are collected corresponding to the different signal phases from the one or more combined responses. The pair of phase separated electrical responses are used to determine electrical properties of the peripheral nerve within the perimeter.