Weighted Gradient Method for Electrical Impedance Imaging
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Solution Overview
Problem
Existing methods for diagnosing diseases using electrical impedance face challenges in accurately detecting and localizing diseases due to the complex and irregular path of electric current through the body, leading to simplifying assumptions that decrease image fidelity and resolution.
Innovation Solution
The method subdivides the body part into finite elements, calculates weight factors based on current density for each element, and uses these weights to correlate impedance measurements, providing a more accurate diagnosis by considering the realistic distribution of electric current and baseline impedances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If simplifying assumptions are made to handle the complex mathematics of electrical impedance imaging, then the computational complexity is reduced, but the image fidelity and resolution decrease
Solution Approach 1:
The body part is divided into a three-dimensional grid of discrete volumetric elements (voxels). This segmentation allows the complex continuous medium to be represented as a finite number of discrete units, making the mathematical problem tractable while preserving spatial resolution. Each voxel's electrical properties can be independently determined through the weighted gradient method.
Solution Approach 2:
The patent transforms the impedance measurement problem into a gradient-based parameter estimation problem. By computing gradients of the objective function with respect to each voxel's electrical parameters, the method efficiently navigates the complex parameter space without requiring simplifying assumptions about current flow patterns, thereby maintaining image fidelity.
2Measurement precision
If the irregular and three-dimensional path of electric current is fully modeled, then the measurement precision improves, but the mathematical complexity and computational requirements increase
Solution Approach 1:
The patent replaces direct physical measurement of complex current paths with a computational gradient-based inversion method. Instead of attempting to directly trace and measure the irregular three-dimensional current paths, the method uses numerical optimization to infer tissue properties from impedance measurements, substituting a computational approach for a complex physical measurement problem.
Solution Approach 2:
The method pre-computes sensitivity matrices and gradient information based on an initial estimate of tissue properties. These pre-computed quantities capture the complex three-dimensional current distribution effects, allowing the actual image reconstruction to proceed efficiently using these prepared data structures without re-solving the full complex forward problem at each iteration.
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 enhances the accuracy of disease detection by providing a weighted element value that indicates the probability of disease at specific locations, improving the ability to differentiate between healthy and diseased states in body parts.
Implementation Method 1
measuring a physical property of a part of the body... electrical impedance measurements... the impedance of a body part that is related to the resistance that the body part offers to the flow of electrical current through it
Implementation Method 2
Electric current does not proceed in straight lines or in a single plane; it follows the path of least resistance... the approximate current distribution is obtained by a numerical computation using a representation of a body part structure
Data Source
AI summary
A method for detecting and diagnosing disease states in a body part is described. The method starts with a preparatory step of modeling the body part as a grid of many finite elements, then calculating an electrical property between two finite elements at which current from two corresponding electrodes flows through the body part. This is termed the weight (influence) of the element. With this baseline information, electrical impedance measurements made at the plurality of electrodes on the periphery of the body part can be used in a diagnostic module to calculate a Weighted Element Value (WEVal) for each element. In a preferred embodiment of invention, the difference in WEVal magnitude between corresponding elements of homologous body parts serves as an indicator of the presence of disease.