Z-Axis Gradient Coil Subcoils for Reduced MRI Artifacts
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Solution Overview
Problem
Existing Z-axis gradient coils in magnetic resonance imaging systems suffer from artifacts due to overlapping magnetic field strengths corresponding to multiple positions along the Z-axis, leading to inaccurate imaging, especially when targeting specific body parts like the head, and are inadequate for whole-body symmetric scans.
Innovation Solution
The gradient coil assembly comprises a Z-axis gradient coil with multiple subcoils arranged along the axial direction, connected in series and parallel configurations to enhance current distribution and maintain consistent magnetic field strength, reducing inflection points and artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single winding path is employed to wind conductors of the Z-axis gradient coil, then the device complexity is reduced, but the imaging precision deteriorates due to sparser conductor distribution and concentrated current causing inflection points and artifacts
Solution Approach 1:
The single winding path is divided into multiple independent winding paths (first, second, third, and fourth winding paths). Each path contains subcoils (first subcoil, second subcoil, third subcoil, fourth subcoil) that can be independently controlled. This segmentation allows for better current distribution and eliminates the inflection point problem while maintaining manageable device complexity through modular construction.
2Adaptability or versatility
If a whole-body symmetric gradient coil is used, then the adaptability for different body parts is improved, but the imaging precision for targeted scans deteriorates due to insufficient gradient coil strength at specific scanning sites
Solution Approach 1:
The gradient coil system transitions from a static, fixed-strength design to a dynamic, adjustable-strength design. By independently controlling the current in each winding path and subcoil, the system can adaptively adjust the gradient field strength according to different scanning requirements, whether whole-body or targeted head scans, thereby maintaining both adaptability and precision.
3Measurement precision
If the gradient coil is narrowed to increase gradient strength for head scans, then the imaging precision for targeted scans is improved, but the ease of operation deteriorates due to hindered access for the human body
Solution Approach 1:
The gradient coil is divided into multiple independent winding paths and subcoils that can be selectively activated. For head scans, only the relevant subcoils (e.g., first and second subcoils) are activated to generate the required gradient field, while other parts remain inactive. This allows high gradient strength in the scanning region without physically narrowing the entire coil structure, thereby maintaining patient accessibility.
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 design improves imaging accuracy by minimizing artifacts and ensuring uniform magnetic field distribution, allowing for targeted scans with enhanced quality and consistency.
Implementation Method 1
A Z-axis gradient coil is an essential component of a magnetic resonance imaging system, responsible for generating a gradient magnetic field along a Z direction
Data Source
AI summary
A gradient coil assembly and a magnetic resonance imaging system comprising a Z-axis gradient coil are provided. The gradient coil assembly comprises a Z-axis gradient coil. The Z-axis gradient coil comprising a first coil and a second coil, the first coil and the second coil being arranged along an axial direction of the Z-axis gradient coil. The first coil comprises a first subcoil and a second subcoil. The first subcoil and the second subcoil extend alongside each other. The second coil comprises a third subcoil and a fourth subcoil. The third subcoil and the fourth subcoil extend alongside each other.