Second-Order Correction Coil Assembly for MR Phase Errors
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Solution Overview
Problem
Concomitant fields generated by gradients in MR systems introduce errors in MR signals, causing artifacts such as pixel shifts, in-plane blurring, and through-plane blurring, which existing methods fail to adequately correct, especially in high-performance gradient coils.
Innovation Solution
A second-order correction coil assembly is introduced, comprising multiple correction coils configured to correct different spatial variations of concomitant fields, decoupled from the gradient coil assembly, allowing asynchronous application of compensation fields to effectively reduce residual phase errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-performance gradient coils are used to improve imaging performance, then gradient strength and imaging capability are enhanced, but second-order concomitant field effects increase causing more severe artifacts and signal errors
Solution Approach 1:
The patent converts the harmful concomitant fields into beneficial correction signals by using dedicated correction coils that generate opposite-phase fields to cancel the unwanted concomitant field effects, thereby enabling high gradient strength while maintaining image quality
Solution Approach 2:
The patent changes the parameter of field order by introducing second-order correction terms that specifically address the quadratic spatial variations caused by high-gradient coils, allowing the system to compensate for the enhanced gradient effects without sacrificing imaging performance
2Device complexity
If conventional gradient coil assemblies are used, then device simplicity is maintained, but residual phase errors and image artifacts remain uncorrected
Solution Approach 1:
The patent segments the coil system into separate functional components: the original gradient coil assembly for generating imaging gradients and additional dedicated correction coils for compensating concomitant field effects, allowing independent optimization of each function while improving overall image accuracy
3Manufacturing precision
If concomitant field correction is implemented to reduce artifacts, then image quality improves, but system complexity and additional hardware requirements increase
Solution Approach 1:
The correction coils are designed with multi-functionality, serving both as concomitant field correction elements and as part of the overall gradient system, thereby reducing the need for entirely separate correction mechanisms and limiting the increase in system 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
The system significantly reduces phase errors from second-order concomitant fields, improving image quality by correcting artifacts in MR images, particularly in 3D imaging and slices away from the isocenter, and enhancing the performance of high-gradient MR systems.
Implementation Method 1
a second-order correction coil assembly including a first second-order correction coil configured to correct effects of a first term of second-order concomitant fields generated by the at least one gradient field
Data Source
AI summary
A magnetic resonance (MR) system for correcting concomitant field effects is provided. The MR system includes a gradient coil assembly including a plurality of gradient coils configured to apply at least one gradient field to a polarizing magnetic field of the MR system. The MR system also includes a second-order correction coil assembly including a first second-order correction coil configured to correct effects of a first term of second-order concomitant fields generated by the at least one gradient field. The system further includes a second-order correction computing device including at least one processor in communication with at least one memory device. The at least one processor is programmed to control the second-order correction coil assembly by instructing the MR system to apply a compensation field to the second-order correction coil assembly asynchronously with the at least one gradient field.