Corrective Magnetic Field Phase Separation for MRI Instability
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Solution Overview
Problem
Magnetic resonance imaging (MRI) systems face challenges with temporal magnetic field instabilities caused by cyclical or sporadic perturbations, leading to inhomogeneities in the main magnetic field, which result in artifacts and ghosts in reconstructed images.
Innovation Solution
The implementation of a method and system that generates a corrective magnetic field with a first and second component having a phase separation, derived from a stability parameter decomposed from a stability field, to counteract identified instabilities in the imaging magnetic field, using electromagnets to produce these components and superimpose them with the main magnetic field to reduce inhomogeneity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a strong static magnetic field is used for MRI imaging, then the polarization of nuclei is improved, but temporal magnetic field instabilities cause inhomogeneities and artifacts in reconstructed images
Solution Approach 1:
The system continuously monitors the main magnetic field for instabilities and automatically generates corrective magnetic fields in response to detected variations, creating a closed-loop feedback system that maintains field homogeneity despite temporal fluctuations
Solution Approach 2:
The system dynamically adjusts the parameters of corrective magnetic fields (amplitude, phase, frequency) based on the characteristics of detected instabilities, allowing adaptive compensation for different types and magnitudes of field variations
2Area of stationary object
If multiple acquisitions are performed to traverse the entire FOV, then complete imaging coverage is achieved, but temporal variations in the BO-field manifest as artifacts or ghosts in reconstructed images
Solution Approach 1:
The system characterizes and models magnetic field instabilities during a calibration phase before actual imaging, storing this information for use during subsequent acquisitions to pre-compensate for expected temporal variations
Solution Approach 2:
The system uses feedback from field monitoring during acquisitions to adjust corrective fields in real-time, ensuring that temporal variations do not manifest as artifacts in the final reconstructed images
3Reliability
If corrective magnetic fields are generated to reduce inhomogeneity, then field homogeneity is improved, but the complexity of the magnetic resonance system increases
Solution Approach 1:
The system uses the existing main magnet structure and gradient coil system to generate corrective fields, making the magnet assembly multi-functional by having it perform both imaging and field correction functions without adding completely separate correction hardware
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 effectively mitigates temporal and spatial magnetic field instabilities, improving image quality by neutralizing or canceling field inhomogeneities, thereby reducing artifacts and enhancing the homogeneity of the imaging magnetic field.
Implementation Method 1
an electromagnet assembly configured to generate a corrective magnetic field according a stability parameter that corrects an instability identified within the imaging magnetic field
Implementation Method 2
superimpose them with the main magnetic field to reduce inhomogeneity
Data Source
AI summary
A method, device, and system for reducing inhomogeneity in an imaging magnetic field during magnetic resonance imaging is described. The method includes generating a corrective magnetic field during imaging, the corrective magnetic field having a first magnetic field component and a second magnetic field component with a phase separation therebetween. The first and second components are generated according to a stability parameter decomposed from a stability field that correct an instability identified within the imaging magnetic field.