Magnetic Induction Spectroscopy Coil Array for Tissue Fluid Monitoring

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Solution Overview

Problem

Current methods for monitoring fluid content in tissues non-invasively are either complex and costly or exhibit poor reproducibility, and magnetic induction spectroscopy (MIS) faces challenges with low signal levels and movement artefacts when used to assess general hydration status in patients.

Innovation Solution

The development of a robust MIS apparatus and method that includes a configuration where the excitation coil and receiver coil are arranged to minimize coil crosstalk, using a second excitation coil paired with a reference coil to cancel out interference, and placing the coils around the tissue sample to reduce movement sensitivity, allowing for accurate fluid content measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If magnetic induction spectroscopy is used to measure tissue fluid content, then non-invasive monitoring capability is achieved, but signal levels are low and measurement precision deteriorates

Engineering Contradiction:
Improvenon-invasive monitoring capabilityVSAvoidsignal level
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The measurement system is divided into separate excitation and detection coils, allowing the excitation coil to generate a strong magnetic field while the detection coil separately measures the induced signal from tissue, thereby improving signal level without compromising non-invasive capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from single-coil measurement to multi-coil array configuration, adding spatial dimension to the measurement system. This allows for better signal detection through multiple measurement points and improved signal-to-noise ratio while maintaining non-invasive operation

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If coils are placed close to tissue for strong signal detection, then measurement sensitivity is improved, but movement artefacts increase

Engineering Contradiction:
Improvemeasurement sensitivityVSAvoidmovement artefact
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The coil system is segmented into multiple smaller coils arranged in an array, which reduces the sensitivity of each individual coil to movement artefacts while collectively maintaining high measurement sensitivity through combined signal processing

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system incorporates reference coils that measure environmental and movement-related interference, and this reference signal is used to compensate for movement artefacts in the main measurement signal, thereby maintaining measurement sensitivity while reducing movement-related errors

Inventive Principle:
Principle #23Feedback

3Device complexity

If single excitation coil is used to simplify apparatus, then device complexity is reduced, but coil crosstalk interference increases

Engineering Contradiction:
Improveapparatus structureVSAvoidcoil crosstalk interference
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The single excitation coil is divided into multiple excitation coils that can be independently controlled, reducing the magnetic field strength required from each coil and thereby minimizing crosstalk interference while maintaining the overall apparatus relatively simple through modular design

Inventive Principle:
Principle #1Segmentation

4Measurement precision

If established methods like tracer dilution or imaging are used, then measurement accuracy is improved, but device complexity and cost increase

Engineering Contradiction:
Improvefluid content measurement accuracyVSAvoidapparatus complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and utilizes the magnetic properties of tissue fluid itself as the measurement mechanism, eliminating the need for external tracers or complex imaging systems. This achieves accurate fluid content measurement through direct magnetic induction on the tissue's inherent properties, thereby reducing device complexity and cost

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using physical tracers or imaging systems, the patent creates a magnetic field copy of the tissue's electrical properties, measuring fluid content through the magnetic induction signal that replicates the tissue's conductive characteristics without requiring additional substances or complex equipment

Inventive Principle:
Principle #26Copying

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

The solution provides a more sensitive and stable measurement of tissue fluid content, reducing the impact of temperature and humidity fluctuations and movement, enabling effective monitoring of hydration status and vital signs like heart rate.

Implementation Method 1

The first excitation coil (46) generates a magnetic field and/or an eddy current in the tissue sample (44)

Methodology Applied
Scientific EffectMagnetic induction: Electromagnetic Induction

Implementation Method 2

The second excitation coil (56) generates a magnetic field and/or an eddy current in the tissue sample (44)

Methodology Applied
Scientific EffectMagnetic induction: Electromagnetic Induction

Data Source

PatentEP3152556B1Apparatus and methods that use magnetic induction spectroscopy to monitor tissue fluid content
Publication Date: 2020.03.11 KONINKLIJKE PHILIPS NV
  • EP3152556B1 patent drawingFigure 1
  • EP3152556B1 patent drawingFigure 2(a)~2(b)
  • EP3152556B1 patent drawingFigure 2(c)

AI summary

There is provided an apparatus for using magnetic induction spectroscopy, MIS, to determine a measure of the fluid content of a tissue sample of a subject, the apparatus comprising a first excitation coil that is to be placed near to the tissue sample for inducing a current in the tissue sample; a reference coil; a second excitation coil that is arranged close to the reference coil and that is for inducing a current in the reference coil; and a control unit that is configured to apply an alternating current to the first excitation coil and the second excitation coil; obtain a measure of the current induced in the tissue sample; and determine a measure of the fluid content of the tissue sample from the measure of the current induced in the tissue sample.