Needle Electrode Array for Tissue Impedance Tomography
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Solution Overview
Problem
Current methods for cancer diagnosis, such as radiological and nuclear imaging, face challenges in distinguishing tumors from inflammatory masses due to unsatisfactory sensitivity and specificity, and invasive procedures like biopsies often yield inconclusive results, highlighting the need for a more precise method to evaluate tissue electrical properties.
Innovation Solution
A system combining electrical-impedance tomography (EIT) and electrical-impedance spectroscopy (EIS) using eight stainless steel electrodes with a multiplexer, current generator, and voltmeter, controlled by a computer or smartphone, to measure tissue impedance across various frequencies, providing high-resolution 2D images and real-time analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If radiological and nuclear imaging methods are used for cancer diagnosis, then morphological and functional evaluation of lesions can be achieved, but the sensitivity and specificity for differential diagnosis remain unsatisfactory
Solution Approach 1:
The patent measures electrical impedance parameters (magnitude and phase) across multiple frequencies to characterize tissue properties. By analyzing impedance spectra and extracting parameters like R0, R90, and phase angle at specific frequencies, the system distinguishes cancerous from non-cancerous tissues based on their unique electrical signatures, thereby improving differential diagnosis precision and reliability
Solution Approach 2:
The patent introduces electrical impedance measurement as an intermediary technique between conventional imaging and histological examination. Impedance spectroscopy serves as a non-invasive mediator that provides functional tissue characterization, enabling more accurate differential diagnosis without requiring tissue sampling or radiation exposure
2Measurement precision
If image-guided biopsies are performed to improve diagnostic precision, then tissue sampling can be better targeted, but the procedures become more invasive and costly
Solution Approach 1:
The patent enables the impedance measurement system to serve multiple functions: it characterizes tissue properties for diagnosis and simultaneously guides biopsy procedures. The real-time impedance feedback allows the same device to both detect and guide tissue sampling, reducing the need for separate imaging-guided biopsy systems and minimizing procedural invasiveness
Solution Approach 2:
The patent performs preliminary electrical impedance characterization of tissues before biopsy procedures. By measuring impedance spectra and generating tissue maps in advance, the system identifies suspicious areas and plans biopsy trajectories, enabling more accurate targeted sampling while reducing the invasiveness of the actual biopsy procedure
3Loss of information
If electrical-impedance tomography is used to provide 2D cross-sectional views, then structural homogeneity can be displayed, but the spatial resolution needs improvement
Solution Approach 1:
The patent enhances the traditional 2D EIT cross-sectional views by adding spectral dimension through multi-frequency impedance measurements. By measuring impedance across a range of frequencies and analyzing the spectral characteristics, the system provides additional information about tissue composition and structure, effectively adding a fourth dimension (frequency) to the spatial mapping, thereby improving spatial resolution and tissue characterization without increasing physical probe complexity
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 reliable discrimination of cancer tissues by generating impedance maps, improving spatial resolution and reducing the invasiveness of biopsies by allowing targeted sampling under guided electrical images, thus enhancing diagnostic precision and reducing false positives and negatives.
Implementation Method 1
System for measuring the electrical impedance in human tissues
Implementation Method 2
Electrical-impedance tomography (EIT) is a technique of reconstruction of the electrical image of the tissues
Implementation Method 3
Electrical-impedance spectroscopy (EIS) is a method for measuring electrical impedance of a substance as a function of the applied frequency
Data Source
Figure 1
AI summary
A system for measuring electrical impedance in human tissues comprising a plurality of needles (10); said plurality of needles (10) being arranged along a circumference; where said plurality of needles (10) have a length greater than 0.5 cm; said plurality of needles (10) being coated with an electrically insulating material throughout their entire length except for a portion (12) having a maximum length of 0.5 mm; each of said plurality of needles (12) being connected to a multiplexer (15); an alternating-current generator (20) being connected to an input of said multiplexer (15); where said current generator (20) sends a current (21) at at least two different frequencies ranging between 10 Hz and 1 MHz; a voltmeter (22) being connected to an output of said multiplexer (15),· a control centre (25) connecting selectively and in succession said current generator (20) to first two needles of said plurality of needles (10); said control centre (25) controlling said multiplexer (15) so as to connect selectively and in succession said voltmeter (22) to second two needles of said plurality of needles (10) according to a predefined scheme; said control centre (25) measuring the impedance between said second two needles at said at least two frequencies; said control centre (25) calculating an image, having a size substantially- equal to that of said circumference, for each of said at least two frequencies corresponding to said measurement of the impedance between said second two needles; said control centre (25) supplying said image to a system for displaying (26) said image.