MRI Magnet Array for Volumetric Tissue Margin Imaging
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Solution Overview
Problem
Current MRI systems for imaging tissue margins during breast cancer surgery are limited by slow image acquisition and inability to provide volumetric mapping, necessitating repeated surgeries if margins are not adequately assessed in real-time.
Innovation Solution
A 2D or 3D MRI system utilizing a stationary array of permanent magnets arranged in a Halbach array to generate an inhomogeneous main magnetic field, with a tissue holder for moving the tissue and RF receive coils for spatial encoding of magnetic resonance signals, eliminating the need for gradient coils and enabling fast volumetric mapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional MRI systems with gradient coils are used for tissue margin imaging, then spatial encoding can be achieved, but image acquisition is slow and volumetric mapping capability is limited
Solution Approach 1:
The patent removes gradient coils from the conventional MRI system, extracting only the essential function of spatial encoding. By using permanent magnets arranged in specific geometric patterns, the system achieves spatial encoding without the complex gradient coil apparatus, thereby simplifying the device while maintaining imaging capability and enabling faster acquisition.
Solution Approach 2:
The patent replaces the mechanical gradient coil system with a static permanent magnet array. Instead of using time-varying magnetic fields generated by gradient coils, the system employs fixed permanent magnets with carefully designed geometries to create spatially varying magnetic field patterns that provide the necessary encoding information.
2Reliability
If conventional MRI systems are used for margin assessment, then imaging can be performed, but repeated surgeries are necessary if margins are not adequately assessed in real-time
Solution Approach 1:
The patent enables preliminary assessment of tissue margins during the surgical procedure itself rather than after completion. By providing real-time or near-real-time imaging feedback, the system allows surgeons to evaluate margin status immediately and perform additional excisions if needed, before the surgery concludes, thereby ensuring complete tumor removal in a single operation.
3Device complexity
If permanent magnets are used to generate the main magnetic field, then system complexity is reduced, but achieving sufficient field homogeneity over the imaging volume becomes difficult
Solution Approach 1:
The patent employs asymmetric arrangements of permanent magnets, specifically using Halbach arrays and other non-uniform geometric patterns. These asymmetric configurations create controlled magnetic field variations that provide spatial encoding information while maintaining adequate field homogeneity over the imaging volume, resolving the conflict between simplicity and precision.
Solution Approach 2:
The patent optimizes various parameters of the permanent magnet system including magnet geometry, spacing, orientation, and material properties. By carefully adjusting these parameters, the system achieves the desired balance between field homogeneity and spatial encoding capability while maintaining the simplicity of using permanent magnets rather than gradient coils.
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 rapid and accurate imaging of tissue margins and volumetric mapping during surgery, reducing the need for additional tissue excisions and improving cosmetic outcomes by providing real-time margin assessment.
Implementation Method 1
a stationary array of magnets arranged to generate an inhomogeneous main magnetic field (B0)
Implementation Method 2
magnetic resonance signals generated by the magnets and RF receive coils
Implementation Method 3
spatial inhomogeneities in the main magnetic field spatially modulate a phase of each of the magnetic resonance signals
Implementation Method 4
one or more RF receive coils adjacent the tissue holder and the magnets
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A tissue imaging system (10) includes a stationary array of magnets (12) arranged to generate an inhomogeneous main magnetic field (B0), a tissue holder (16) adjacent the array of magnets (12) and operative to move tissue (14) placed therein about and/or along a coordinate axis, one or more RF receive coils (20) adjacent the tissue holder (16) and the magnets (12), and an MRI processor in communication with the magnets (12), the RF receive coils (20) and the tissue holder (16). An image of the tissue (14) is created by using spatial encoding of magnetic resonance signals generated by the magnets (12) and RF receive coils (20) for different spatial orientations of the tissue (14) moved by the tissue holder (16) with respect to the magnets. Spatial inhomogeneities in the main magnetic field spatially modulate a phase of each of the magnetic resonance signals.