Integrated Shim Conductor for MRI Local Coil Homogeneity
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Solution Overview
Problem
Existing magnetic resonance tomography systems face challenges in achieving homogeneous magnetic fields, particularly in extreme anatomical regions due to patient-induced inhomogeneities and spatial localization, which affects image quality and fat saturation techniques.
Innovation Solution
A local coil arrangement with conductors arranged orthogonally to the magnetic field, generating a compensation magnetic field that is localized and minimally attenuated by interfering fields, allowing for effective compensation of residual inhomogeneities without significant side effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional shim coils are used to compensate magnetic field inhomogeneities, then magnetic field homogeneity is improved, but the device complexity and spatial requirements increase
Solution Approach 1:
The patent combines the shim conductor directly into the coil holder structure, merging two previously separate components (shim coil and coil holder) into a single integrated unit. This reduces device complexity while maintaining magnetic field homogeneity compensation capability.
Solution Approach 2:
The coil holder is designed to serve multiple functions: it provides mechanical support for the coil elements and simultaneously acts as a shim conductor for magnetic field homogeneity compensation. This multi-functionality eliminates the need for separate shim coils, reducing overall device complexity.
2Manufacturing precision
If passive shim coils are used to compensate residual inhomogeneity, then magnetic field homogeneity is improved, but the volume and positioning requirements increase
Solution Approach 1:
The shim conductor is integrated into the coil holder structure, eliminating the need for separate passive shim coils. This integration significantly reduces the volume required for shim compensation while maintaining effectiveness.
Solution Approach 2:
The shim conductor is positioned locally at the coil holder to address specific local inhomogeneities in the detection zone, rather than requiring large-volume passive shim coils that occupy significant space.
3Manufacturing precision
If conductors are arranged to generate compensation magnetic field, then magnetic field homogeneity is improved, but interfering magnetic fields may attenuate the compensation effect
Solution Approach 1:
The conductor is positioned specifically in the edge area of the detection zone to generate compensation magnetic fields localized to regions with greatest inhomogeneity. The return conductor is placed outside the detection zone to minimize interfering fields within the imaging region.
Solution Approach 2:
The return conductor acts as an intermediary element that carries current back to complete the circuit while generating interfering fields outside the detection zone, thereby protecting the imaging region from attenuation while maintaining electrical circuit functionality.
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 solution enables simple and effective compensation of localized magnetic field inhomogeneities, improving image quality and diagnostic usefulness by maintaining signal-noise ratio and adaptability to individual patient inhomogeneities.
Implementation Method 1
The at least one conductor is arranged in the mechanical holding structure such that the at least one conductor extends orthogonally to a direction of a basic magnetic field. Field lines of a compensation magnetic field generated when the at least one conductor is exposed to direct current or low-frequency alternating current
Data Source
AI summary
When a portion of a structure enclosing a local coil is inserted in a homogeneity region of a basic magnetic field of a magnetic resonance system, the local coil is operable to receive magnetic resonance signals originating from a specific detection zone for the local coil arrangement. At least one conductor is arranged in the structure. Field lines of a compensation magnetic field generated by current encircling the conductor form a compensation magnetic field angle with the basic magnetic field in an edge area of the detection zone. Return conductors complete an electric circuit containing the conductor and extend in the direction of the basic magnetic field and/or are arranged such that field lines of an interfering magnetic field counteracting the compensation magnetic field encircle the respective return conductor and form an interfering magnetic field angle with the basic magnetic field in the edge area.