MRI Gradient Coil Wire Position Optimization
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Solution Overview
Problem
Existing MRI gradient coil designs face challenges in achieving optimal force, torque, and shielding performance due to poorly balanced discretized wire patterns, leading to noise, destructive movement, and imaging artifacts.
Innovation Solution
A method that calculates the electromagnetic stream function and iteratively optimizes the contouring of the stream function to improve force, torque, and shielding performance by varying contour spacing and offset, using techniques like intelligent parametric sweeps or gradient descent optimization, to precisely position discrete wires without compromising electromagnetic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the stream function is discretized into a set number of conducting paths using conventional methods, then the electromagnetic field distribution can be approximated, but the force and torque balancing is poor leading to noise and destructive movement
Solution Approach 1:
The patent applies preliminary action by first calculating the ideal stream function to define the electromagnetic field distribution, then subsequently optimizing the contouring parameters of the discretized wire positions to achieve force and torque balancing. This two-stage approach ensures that electromagnetic performance is established first, followed by mechanical performance optimization, resolving the contradiction between field accuracy and force/torque balancing.
2Ease of manufacture
If the stream function is discretized into individual current paths using conventional methods, then the coil can be manufactured, but the shielding is unsatisfactory contributing to increased eddy currents and imaging artifacts
Solution Approach 1:
The patent implements feedback by using an optimization algorithm that iteratively adjusts the contouring parameters of the discretized wire positions based on calculated performance metrics including shielding effectiveness. The algorithm evaluates the impact of wire position variations on eddy currents and imaging artifacts, then refines the positions to minimize these harmful effects while maintaining manufacturability.
3Reliability
If exhaustive user input or guided iteration is used to achieve the best coil performance, then the wire positions can be optimized, but the design process becomes complex and time-consuming
Solution Approach 1:
The patent applies self-service by implementing an automated optimization algorithm that independently adjusts the contouring parameters of the discretized wire positions. The system calculates performance metrics including force, torque, and shielding, then automatically iterates to find optimal wire positions without requiring exhaustive user input or manual guided iteration, thereby reducing design complexity while maintaining high coil performance.
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 performance metrics of MRI gradient coils, achieving better force and torque balancing, improved shielding, and reduced mutual inductance, thereby improving the overall efficiency and accuracy of MRI imaging.
Implementation Method 1
Gradient coils produce orthogonal magnetic fields that impress spatially-encoded information upon the received signal during an MRI acquisition
Implementation Method 2
the discretized wire pattern representations are poorly force and torque balanced (contributing to noise and destructive movement of the gradient coil during operation)
Implementation Method 3
have unsatisfactory shielding (contributing to increased eddy currents which can result in imaging artifacts)
Data Source
AI summary
The present disclosure reports on a method to first determine the required electromagnetic stream function, and then iterate on the contouring of the stream function to optimize the force, torque, shielding, and/or mutual inductance of the design after-the-fact without compromising the electromagnetic performance and an electromagnetic coil manufacture according to the method. These parameters are sensitive to the precise positioning of the discrete wires.