EIT Sensor Device Spatial Orientation Compensation
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Solution Overview
Problem
Current electrical impedance tomography (EIT) technologies face challenges in accurately monitoring lung function and compensating for gravitational influences, leading to difficulties in detecting lung collapse and oxygenation issues in patients, especially in intensive care settings, due to inaccuracies in measured voltages and the ill-posed nature of impedance estimation.
Innovation Solution
Incorporating spatial information about the body's orientation and position relative to the gravitational vector into EIT imaging, using sensors like tri-axial acceleration sensors and strain gauges to adjust impedance distribution measurements, thereby enhancing the accuracy of EIT images and movies by accounting for gravitational effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spatial information sensors (tri-axial acceleration sensors, strain gauges) are incorporated into the EIT sensor device, then measurement precision and reliability of EIT images are improved by accounting for gravitational effects, but device complexity increases due to additional sensors and processing requirements
Solution Approach 1:
The patent introduces spatial information (gravitational vector data from tri-axial acceleration sensors and body orientation data from strain gauges) as an intermediary to mediate between the raw EIT voltage measurements and the final impedance distribution reconstruction. This intermediary spatial information allows the system to compensate for gravitational effects on lung perfusion and ventilation without fundamentally changing the EIT measurement physics, thereby improving measurement precision while adding only moderate device complexity through supplementary sensors rather than redesigning the core EIT system
Solution Approach 2:
The patent changes the parameter set used in EIT image reconstruction by incorporating spatial parameters (orientation angles, gravitational vector components) alongside traditional voltage measurements. This parameter expansion allows the reconstruction algorithm to account for gravitational influences on lung zones and blood flow distribution, improving the accuracy of impedance distribution measurements while the additional computational parameters are managed through enhanced processing algorithms
2Reliability
If regularization methods with a-priori knowledge are used to overcome the ill-posed nature of impedance estimation, then reliability of EIT images is improved, but loss of information occurs due to assumptions and restrictions imposed on the solution
Solution Approach 1:
The patent applies local quality by using spatially varying regularization parameters that are adapted to different lung zones based on gravitational orientation. Instead of applying uniform assumptions across the entire thorax, the system adjusts regularization strength and a-priori knowledge constraints locally according to the patient's body position and the expected gravitational effects on blood flow and ventilation in specific regions, thereby improving reliability while preserving local information that would be lost with uniform regularization
Solution Approach 2:
The patent makes the regularization parameters dynamic by updating them based on real-time spatial information from acceleration sensors and strain gauges. As the patient's body position changes, the a-priori knowledge and regularization constraints are dynamically adjusted to reflect the new gravitational orientation and expected physiological changes in lung zones, improving reliability across varying conditions while minimizing information loss by adapting to actual patient state rather than relying on static assumptions
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 creation of clinically usable, reliable EIT difference images and improved reference images, allowing for real-time monitoring of lung function and facilitating life-saving treatments by accurately depicting lung zones and ventilation dynamics.
Implementation Method 1
spatial information comprises information about the orientation and/or position of the sensor... determining spatial orientation of a test person... with respect to the direction of the gravity vector
Implementation Method 2
at least one sensor for gathering information on changes in the circumference or the dilation of the electrode array during inspiration... a strain gauge... The strain gauge is e.g. arranged on the impedance distribution measuring device
Data Source
AI summary
A sensor device for EIT imaging comprises an electrode array for measuring an impedance distribution, with at least one sensor for determining spatial orientation of the electrode array coupled to the electrode array. EIT imaging instrument is connectable to a sensor for determining spatial orientation of a test person, and optionally in addition connectable to a sensor for gathering information on electrical and/or acoustic activity and/or a sensor for gathering information on dilation. A computing device is connected or integrated for adjusting impedance data based on spatial data, which spatial data describe the spatial orientation of a test subject. An EIT imaging method for measuring an impedance distribution and adjusting said measured impedance distribution comprises measuring impedance distribution by using an impedance distribution measuring device comprising an electrode array, and transforming the measured impedance distribution into EIT images.