EIT Electrode Array Shape Adaptation via Impedance Reference Matching
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Solution Overview
Problem
Electrical impedance tomography (EIT) devices face challenges in accurately imaging the lungs due to deviations in the circumferential shape of the electrode array from an average elliptical shape, which affects image reconstruction and requires manual input of patient-specific data for correction, leading to inefficiencies and potential errors in clinical practice.
Innovation Solution
An EIT device with a calculation and control unit that determines the current elliptical circumferential shape of the electrode array using selected measured signals, compares them to pattern signal traces, and generates a control signal to adapt the image reconstruction algorithm, allowing for automatic consideration of the electrode array's shape without needing additional patient data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual input of patient-specific data is used for correction, then image reconstruction accuracy is improved, but device complexity and time consumption increase
Solution Approach 1:
The electrode array automatically determines its own circumferential shape by comparing measured impedance values against stored reference data for average body shapes. This self-characterization eliminates the need for manual patient data input and automatic shape adaptation, resolving the contradiction by making the system self-sufficient without increasing complexity
Solution Approach 2:
Reference impedance data for average body shapes (cylindrical, conical, spherical) are pre-stored in the device memory. During operation, the system automatically compares measured values against these references to determine the actual shape, performing the correction action in advance without requiring manual patient-specific measurements
2Measurement precision
If manual input of patient-specific data is required, then image reconstruction accuracy is improved, but productivity and ease of operation deteriorate
Solution Approach 1:
The system automatically performs shape determination and adaptation without requiring clinical staff to manually measure or input patient anthropometric data. The electrode array itself provides the characterization data by comparing its measured impedance values against stored references, eliminating time-consuming manual procedures and improving clinical workflow efficiency
3Device complexity
If the average elliptical shape is assumed, then device complexity is reduced, but measurement precision and reliability worsen due to deviations from actual shape
Solution Approach 1:
The system dynamically adapts the reconstruction algorithm parameters based on the determined actual shape of the electrode array. By comparing measured impedance values against stored references for different body shapes, the system identifies the matching shape and adjusts reconstruction parameters accordingly, maintaining high accuracy without requiring complex manual configuration
Solution Approach 2:
Multiple reference impedance data sets for different average body shapes (cylindrical, conical, spherical with varying aspect ratios) are pre-computed and stored. The system automatically selects and applies the appropriate reference during operation, performing the adaptation in advance without increasing operational complexity
4Measurement precision
If additional patient-specific information is collected, then image reconstruction accuracy is improved, but ease of operation and time consumption worsen
Solution Approach 1:
The electrode array automatically characterizes the actual body shape by comparing its measured impedance values against stored reference data during normal operation. This self-characterization process requires no additional patient data collection, measurements, or user input beyond the standard EIT measurement setup, maintaining ease of operation while achieving accurate shape-adapted reconstruction
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
Enables accurate and efficient imaging of lung ventilation by automatically accounting for the elliptical shape of the electrode array, reducing the need for manual data input and minimizing errors, thus improving the quality of tidal images without requiring additional patient-specific information.
Implementation Method 1
an electrical feed signal is fed to two feeding electrodes
Implementation Method 2
measured signals are acquired in each of the measuring runs at a selection of at least two electrodes located opposite the two feeding electrodes
Data Source
AI summary
An electrical impedance tomography device (1) includes an electrode array, including a plurality of electrodes (33) arranged spaced apart from one another, a signal feed unit (51) and a signal acquisition unit (50). A calculation and control unit (70) is configured to determine a current elliptical circumferential shape (20′) of the electrode array on a thorax (34) of a human being and to provide a control signal (79), which indicates the elliptical circumferential shape (20) of the electrode array. The calculation and control unit (70) may be configured as a central unit or an array of distributed units (cloud computing) in order to determine and to provide the current elliptical circumferential shape (20′).