Local Maxwell Tomography for Electrical Property Mapping
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Solution Overview
Problem
Current methods for noninvasive mapping of electrical properties in tissues or materials face challenges such as instability, ill-posedness, and limitations in resolution and robustness, particularly in determining absolute RF phase and magnetization distribution in MRI, which hinders accurate volumetric mapping and diagnostic applications.
Innovation Solution
The Local Maxwell Tomography (LMT) approach provides a noninvasive method for mapping electrical properties by using cross-sectional magnetic resonance measurements of RF magnetic field perturbations, eliminating assumptions about RF phase and coil/field/magnetization structure, and determining high-frequency electrical property distributions without prior assumptions, enabling accurate mapping of conductivity and permittivity with spatial variations and anisotropies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If MRI-based techniques are used to map electrical properties noninvasively, then volumetric information about internal magnetic fields can be obtained, but absolute RF phase distribution and magnetization distribution cannot be determined due to fundamental limitations in signal excitation and detection
Solution Approach 1:
The patent introduces an intermediary approach by using multiple RF coils to measure magnetic field perturbations caused by electrical properties. Instead of directly measuring the inaccessible absolute RF phase, the system uses the magnetic field perturbations as an intermediary that can be measured and from which electrical properties can be derived through Maxwell's equations.
Solution Approach 2:
The patent changes the measurement parameters from direct RF phase measurement to magnetic field perturbation measurement. By measuring the curvature of magnetic fields using multiple RF coils and applying Maxwell's equations, the system can determine electrical properties without needing to measure the fundamentally inaccessible absolute RF phase directly.
2Ease of operation
If Electrical Impedance Tomography (EIT) is used for noninvasive electrical property mapping, then surface-based measurements can be converted to property maps, but the resolution and robustness are limited due to ill-posed inverse problems
Solution Approach 1:
The patent replaces the electrical measurement system (EIT) with a magnetic resonance-based system. Instead of using electrical probes or surface-based electrical measurements that lead to ill-posed inverse problems, the system uses MRI-based magnetic field measurements combined with Maxwell's equations to directly calculate electrical properties, thereby improving spatial resolution and robustness.
3Measurement precision
If invasive probes are used for electrical property measurement, then accurate local measurements can be obtained, but the local environment is disturbed and true cross-sectional mapping is precluded
Solution Approach 1:
The patent uses magnetic field perturbations as an intermediary to indirectly measure electrical properties without physical contact. The RF coils generate magnetic fields that are perturbed by the electrical properties of tissues, and these perturbations are measured and used to calculate conductivity and permittivity distributions, thereby avoiding environmental disturbance while maintaining measurement accuracy.
4Device complexity
If approximations involving symmetry assumptions are applied to derive absolute RF phase, then calculation can be simplified, but the approximations break down when fields are most perturbed by tissue properties at high operating frequencies
Solution Approach 1:
The patent changes the fundamental measurement parameter from RF phase to magnetic field perturbation curvature. This parameter change allows the system to work at high operating frequencies where tissue property perturbations are most significant, without relying on symmetry assumptions that break down in these conditions. The approach uses multiple RF coils to measure field curvatures that directly relate to electrical properties through Maxwell's equations.
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
LMT facilitates precise, noninvasive determination of electrical properties and absolute phase distribution, improving resolution and robustness, and enabling quantitative imaging and accurate mapping of electromagnetic fields, overcoming previous limitations in MRI-based techniques.
Implementation Method 1
Magnetic Resonance Imaging ('MRI') can provide noninvasive volumetric information about the interior magnetic environment of tissue or materials
Implementation Method 2
cross-sectional magnetic resonance measurements of the perturbations of RF magnetic fields
Implementation Method 3
local Maxwell tomography ('LMT'), which can facilitate noncontact mapping of electrical properties, based on cross-sectional magnetic resonance measurements of the perturbations of RF magnetic fields
Data Source
AI summary
Exemplary system, method, and computer-accessible medium can be provided for determining at least one property (e.g., an electrical property or a cross-section property) of at least one target. For example, it is possible to determine electromagnetic-field-related quantities associated with signals provided from the target(s). The electromagnetic-field-related quantities can be provided to procedures to relate the electromagnetic-field-related quantities to a plurality of unknown electrical property values and residual field-related unknown values of the target(s). The property(ies) of the target(s) can be determined by determining the plurality of unknown electrical property values and residual field-related unknown values of the target(s).