Blood Analyte Estimation Using Multi-Frequency EIT
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Solution Overview
Problem
Existing non-invasive methods for estimating blood analyte concentration, such as those using electrical impedance tomography (EIT), face challenges due to tissue heterogeneity, motion artifacts, humidity, and temperature variations.
Innovation Solution
The method involves acquiring EIT images within a thoracic measurement region, determining a region of interest (ROI) that includes a section of the lungs, and calculating blood analyte concentration based on impedance values from these images, which reduces sensitivity to environmental and tissue-related factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If non-invasive methods using electrical impedance tomography (EIT) are used to estimate blood analyte concentration, then the measurement is non-invasive and convenient, but the measurement precision is reduced due to tissue heterogeneity, motion artifacts, humidity, and temperature variations
Solution Approach 1:
The patent introduces an intermediary calibration process that establishes a relationship between EIT impedance measurements and actual blood analyte concentrations. By using a calibration curve generated from controlled measurements, the system mediates between the indirect EIT measurements and the target analyte concentration, compensating for tissue heterogeneity and environmental variations through the calibration model.
Solution Approach 2:
The patent measures impedance at multiple frequencies rather than a single frequency. By acquiring impedance values across a frequency spectrum and analyzing the frequency-dependent behavior, the system extracts more robust parameters that are less sensitive to tissue heterogeneity and environmental factors, thereby improving measurement precision while maintaining non-invasive operation.
2Ease of operation
If impedance measurements are taken from skin and subcutaneous tissue, then the measurement is easily accessible, but the reliability is reduced due to tissue heterogeneity and environmental factors
Solution Approach 1:
The system transitions from single-frequency to multi-frequency impedance measurements. By analyzing impedance across multiple frequencies, the system captures the frequency-dependent properties of different tissue types, enabling differentiation between tissue layers and more reliable extraction of blood-related parameters despite skin and subcutaneous tissue variability.
Solution Approach 2:
The patent implements a calibration feedback mechanism where the system continuously refines its measurements by comparing EIT-derived impedance values against known or reference analyte concentrations. This feedback loop allows the system to adapt to individual tissue characteristics and environmental conditions, improving reliability while maintaining ease of operation.
3Device complexity
If single-frequency impedance measurement is used, then the device complexity is reduced, but the measurement precision is insufficient due to sensitivity to tissue composition variations
Solution Approach 1:
The patent extends the measurement from single-frequency to multi-frequency impedance analysis. By acquiring impedance data at multiple frequencies and utilizing the frequency-dependent characteristics of biological tissues, the system extracts more informative parameters that improve measurement precision without requiring proportionally complex hardware, as the same electrodes can measure across multiple frequencies through sequential or simultaneous excitation.
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 allows for a non-invasive measurement of blood analyte concentration that is less affected by tissue heterogeneity, temperature variations, and environmental factors, providing a more reliable estimation.
Implementation Method 1
The present disclosure provides a method and device for estimating blood analyte concentration using electrical impedance tomography (EIT)
Data Source
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AI summary
The present disclosure concerns a method for determining the concentration of a blood analyte of a user, comprising: providing an apparatus (10) configured to acquire electrical impedance tomography (EIT) images within a measurement region of the thorax of the user, each EIT image comprising a plurality of EIT pixels, each of said EIT pixels comprising at least a first and second impedance values (Z[f1], Z[f2]) corresponding, respectively to a first and second measurement frequencies (f1, f2); using the apparatus (10) to measure a time-sequence of EIT images of said measurement region during a predetermined measuring time covering at least one heart cycle; determining a region of interest (ROI) within the measurement region, said ROI comprising at least a section of the lungs; and calculating the blood analyte concentration based on the impedance values of the EIT pixels within said ROI, from said time-sequence of EIT images. The present disclosure further concerns the apparatus (10) performing the method.