MRI Apparatus Field Mapping for Image Quality Control
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Solution Overview
Problem
Magnetic resonance imaging (MRI) systems face challenges in maintaining spatial linearity and uniformity of gradient and static magnetic fields, leading to image quality deterioration, especially at the periphery of the imaging region, due to limited effective field of view and nonlinear gradient magnetic field coils, which can result in inefficient imaging and potential magnetic stimulation hazards.
Innovation Solution
A magnetic resonance imaging apparatus and method that includes a generation unit for creating magnetic fields, a presumption unit to assess image quality deterioration, a determination unit to identify inappropriate regions, and a setting unit to adjust the imaging region based on operator instructions, along with a reconstruction unit to reconstruct images while informing the operator of potential image quality issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the imaging region is expanded beyond the efficient field of view, then the imaging efficiency is improved, but the image quality deteriorates due to magnetic field non-uniformity and gradient non-linearity
Solution Approach 1:
The system performs preliminary mapping of the magnetic field distribution and gradient non-linearity characteristics before imaging. The computer stores information about regions where image quality deteriorates, allowing the operator to set the imaging region with full awareness of quality limitations, thus efficiently utilizing the available field of view without compromising diagnostic quality
Solution Approach 2:
The system provides feedback to the operator by displaying stored magnetic field distribution information and gradient non-linearity characteristics. This feedback enables the operator to adjust the imaging region settings to optimize the balance between imaging efficiency and image quality based on actual magnetic field conditions
2Object-affected harmful factors
If the gradient magnetic field coil is designed with nonlinear shape to reduce magnetic stimulation, then the safety is improved, but the spatial linearity of the gradient magnetic field deteriorates
Solution Approach 1:
The system converts the harmful effect of gradient non-linearity into useful information by mapping and storing the actual magnetic field distribution. Instead of treating non-linearity as a defect to be eliminated, the system utilizes this characteristic to provide accurate spatial encoding information, allowing the nonlinear coil design to reduce magnetic stimulation while maintaining imaging utility through computational correction
3Manufacturing precision
If the imaging region is set small to ensure quality within efficient field of view, then the image quality is maintained, but the imaging efficiency deteriorates
Solution Approach 1:
The system performs preliminary characterization of the magnetic field distribution and identifies regions where image quality deteriorates before actual imaging. This advance knowledge allows the operator to set the imaging region to maximize coverage while avoiding areas with unacceptable quality, thus improving efficiency without sacrificing quality where it matters
Solution Approach 2:
The system applies different quality standards to different regions of the imaging field. By mapping the actual magnetic field uniformity and gradient linearity, the system identifies which regions meet diagnostic quality requirements and which do not, allowing selective imaging of acceptable regions while excluding poor-quality areas
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 enables efficient use of the imaging region, prevents image quality deterioration by identifying and avoiding inappropriate regions, and enhances operator control over imaging parameters to maintain optimal image quality, thereby improving the efficiency and safety of MRI procedures.
Implementation Method 1
a generation unit generating a magnetic field
Data Source
AI summary
A magnetic resonance imaging apparatus includes a generation unit configured to generate a magnetic field, a reconstruction unit configured to reconstruct an image for a subject on the basis of a magnetic resonance signal radiated from the subject in the magnetic field, a presumption unit configured to presume a distribution of an image quality deterioration degree occurring in the image on the basis of a precision at which the generation unit generates the magnetic field, and a creation unit configured to create a display image showing the distribution of the image quality deterioration degree on the image.