Electroimpedance Tomography Phase Separation for Lung Perfusion
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Solution Overview
Problem
Current medical imaging technologies, such as electroimpedance tomography (EIT), face challenges in effectively visualizing and analyzing perfusion and ventilation data of the lung and heart, leading to difficulties in distinguishing between perfusion and ventilation constellations and quantifying perfusion accurately due to overlapping impedance changes and phase shifts in blood flow.
Innovation Solution
A method and system for processing and visualizing data using cardiac- and perfusion-related signals (CPRS) that involves determining phase information and generating location-related perfusion variables, allowing for a quantifiable analysis of perfusion in lung and heart regions by separating CPRS into synchronized cardiac and perfusion-related signals (sCPRS) and ventilation-related signals (VRS), and calculating ventilation-perfusion ratios (V/Q) for improved visualization and diagnosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If electroimpedance tomography is used to visualize perfusion and ventilation data, then non-invasive monitoring is achieved, but the ability to distinguish between perfusion and ventilation constellations deteriorates due to overlapping impedance changes
Solution Approach 1:
The patent segments the overlapping impedance signal into distinct perfusion and ventilation components by analyzing phase information. Perfusion-related impedance changes and ventilation-related impedance changes are separated based on their different phase characteristics relative to the cardiac cycle, allowing clear distinction between these physiological processes while maintaining non-invasive monitoring.
Solution Approach 2:
The patent changes the parameter used for analysis from simple impedance magnitude to impedance phase information. By examining the phase angle of impedance changes relative to the cardiac cycle, the system can differentiate between perfusion (in-phase with cardiac cycle) and ventilation (out-of-phase with cardiac cycle), thereby improving measurement precision without increasing invasiveness.
2Device complexity
If traditional EIT processing methods are used, then data processing is simple, but quantification of perfusion deteriorates due to phase shifts in blood flow
Solution Approach 1:
The patent applies preliminary phase correction to the impedance signals before quantification. By pre-aligning the phase of perfusion-related impedance changes with the cardiac cycle reference, the system eliminates phase shift artifacts that would otherwise corrupt perfusion quantification, enabling accurate measurement without requiring complex real-time processing during blood flow analysis.
Solution Approach 2:
The patent introduces the cardiac cycle as an intermediary reference signal. This reference serves as a mediator to which both perfusion and ventilation signals are compared, allowing the system to separate and quantify their respective contributions to the total impedance change while maintaining relatively simple processing algorithms.
3Measurement precision
If contrast media is used to improve perfusion visualization, then image quality improves, but patient safety deteriorates due to additional physical burden
Solution Approach 1:
The patent enables the system to use the patient's own physiological signals (electrical activity of the heart, natural impedance changes during cardiac cycle) as the reference for perfusion measurement. This self-service approach eliminates the need for external contrast media, as the body's inherent electrical and mechanical properties provide sufficient information for accurate perfusion visualization without additional physical burden.
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 clear and quantitative visualization of perfusion and ventilation in lung regions, overcoming the limitations of overlapping impedance changes and phase shifts, allowing for accurate diagnosis and monitoring of lung conditions without the need for contrast media or ECG synchronization.
Implementation Method 1
Devices for electroimpedance tomography (EIT) are known from the state of the art. These devices are designed and provided for generating an image, a plurality of images or a continuous sequence of images from signals obtained by means of electroimpedance measurements
Data Source
AI summary
A device and a method (100) for the processing of data (501), which were obtained by an imaging method, make possible an improvement in a location-specific visualization of the perfusion of the lung. With a reference to a comparison variable, a location-specific variable (503), characteristic of a period of observation, regarding the perfusion of the lung and heart region, is determined and provided as an output signal.