MRI Eddy Current Compensation via Configuration-Dependent Gradient Adaptation
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Solution Overview
Problem
Magnetic resonance imaging systems face image distortions and ghosting effects due to undesired eddy currents generated by electrically conductive objects, including additional devices positioned within the system, which are not accounted for in existing eddy current compensation methods.
Innovation Solution
An MR imaging system with a magnetic gradient coil system, a digital data storage unit for parameter sets, and detection means to modify the gradient magnetic field based on the presence, position, and orientation of additional devices, enabling real-time eddy current correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If eddy current compensation is performed using fixed parameter sets for standard configurations, then compensation accuracy is maintained for those configurations, but image distortions and ghosting effects occur when additional devices are present
Solution Approach 1:
The patent implements dynamic adaptation of eddy current compensation by detecting the presence and configuration of additional devices, then selecting or adjusting parameter sets accordingly. The system transitions from static fixed parameter sets to dynamic configuration-dependent parameter selection, allowing real-time adaptation to different scanning configurations and additional device arrangements.
Solution Approach 2:
The patent changes the parameters used for eddy current compensation based on detected configuration information. Different parameter sets are stored and selected according to the presence and position of additional devices, allowing the compensation characteristics to be adjusted to match the actual magnetic field distortions caused by specific configurations.
2Productivity
If gradient magnetic field is applied without considering additional devices, then scanning efficiency is maintained, but eddy currents cause image distortions and ghosting effects
Solution Approach 1:
The patent performs preliminary detection of additional devices and their configurations before the actual MR scanning begins. Based on this detection, the appropriate eddy current compensation parameter sets are pre-selected and prepared, allowing the gradient magnetic field application to proceed with proper compensation already in place, thus maintaining scanning efficiency while eliminating harmful eddy current effects.
Solution Approach 2:
The patent implements a feedback mechanism where the detection system continuously monitors for the presence and configuration of additional devices, and this information feeds back to adjust the eddy current compensation parameters. This closed-loop approach ensures that the compensation remains optimized for the actual scanning configuration without requiring manual intervention or reducing scanning speed.
3Measurement precision
If configuration-dependent parameter sets are implemented, then eddy current compensation accuracy is improved, but system complexity increases
Solution Approach 1:
The patent segments the eddy current compensation into multiple discrete parameter sets, each optimized for specific configurations. Rather than implementing a single complex adaptive algorithm, the system divides the compensation task into manageable segments (parameter sets) that can be selected based on detected configuration, simplifying the overall system architecture while maintaining high accuracy.
Solution Approach 2:
The patent implements an automated detection and parameter selection system that performs self-service configuration-dependent compensation. The system automatically detects additional devices, determines their configuration, and selects the appropriate parameter sets without requiring manual intervention or complex real-time calculations, thus improving accuracy while limiting the increase in operational 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 effectively compensates for eddy currents caused by additional devices, reducing image distortions and ghosting effects, and enabling precise MR imaging by adapting the gradient magnetic field in real-time to the specific configuration of these devices.
Implementation Method 1
a magnetic gradient coil system including at least one magnetic gradient coil and at least one magnetic gradient coil driver unit for providing a predetermined temporal electrical current profile to the at least one magnetic gradient coil
Implementation Method 2
the additional device is capable of generating an eddy current in at least a portion of the additional device when being exposed to the generated gradient magnetic field
Data Source
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AI summary
A magnetic resonance imaging system (10) comprises a magnetic gradient coil system (22) configured for generating gradient magnetic fields by providing a predetermined temporal electrical current profile to at least one magnetic gradient coil in accordance with a desired magnetic resonance examination mode. An additional device (50), which is not part of the original magnetic resonance imaging system (10) as such, is intended to be positioned within an inner region (44) of the magnetic resonance imaging system (10) for special examination or other purposes. The additional device (50) is capable of generating an eddy current in at least a portion of the additional device (50) when being exposed to the generated gradient magnetic field. The magnetic resonance imaging system (10) is configured for modifying the predetermined electrical current profile at least on the basis of at least one predetermined parameter set upon receipt of an information indicative of a presence of at least one additional device (50) within an inner region (44) of the magnetic resonance imaging system (10); and - a method of operating a magnetic resonance imaging system (10) with regard to generating a gradient magnetic field by at least one magnetic gradient coil of a gradient coil system (22) in the presence of at least one additional device (50).