MRI Coil Selection to Reduce Annefact Artifacts
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Solution Overview
Problem
Magnetic resonance imaging (MRI) systems face challenges in reducing annefact artifacts, which are introduced by nonlinear gradient fields, leading to a tradeoff between artifact reduction and signal-to-noise ratio (SNR) when deactivating coil elements that receive signals from these regions.
Innovation Solution
The method involves grouping RF coil elements into receive element groups (REGs), generating sensitivity maps, determining signal contributions from regions of interest and annefact source regions, and selectively activating REGs based on their sensitivity to these signals to minimize annefact artifacts during scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If coil elements sensitive to nonlinear gradient fields are deactivated to reduce annefact artifacts, then image quality improves, but signal-to-noise ratio decreases
Solution Approach 1:
The patent divides the RF coil array into multiple receive element groups (REGs), where each REG contains a subset of coil elements. This segmentation allows selective activation of REGs that are less sensitive to annefact artifacts while maintaining sufficient signal-to-noise ratio, thus resolving the contradiction between artifact reduction and SNR preservation
Solution Approach 2:
The patent implements dynamic REG selection based on sensitivity maps and annefact sensitivity factors. The system adaptively determines which REGs to activate by evaluating their sensitivity to both the region of interest and annefact source regions, allowing optimal balance between artifact reduction and signal quality for each imaging scenario
2Reliability
If all coil elements are activated to maintain signal-to-noise ratio, then signal quality improves, but annefact artifacts increase
Solution Approach 1:
The patent applies local quality by assigning different activation states to different REGs based on their spatial sensitivity characteristics. REGs with high annefact sensitivity are deactivated or downweighted, while REGs with low sensitivity remain active, creating a non-uniform activation pattern that locally optimizes the balance between artifact reduction and signal quality
Solution Approach 2:
The patent changes the operational parameters of the coil array by dynamically adjusting which REGs are active based on calculated sensitivity values and annefact sensitivity factors. This parameter change allows the system to adaptively optimize performance by modifying the effective coil configuration for each imaging scenario
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 reduces or eliminates annefact artifacts in reconstructed images while maintaining a strong signal-to-noise ratio by strategically deactivating coil elements sensitive to nonlinear gradient fields, thereby improving image quality.
Implementation Method 1
The hydrogen nuclei are excited by a radio frequency signal at or near the resonance frequency of the hydrogen nuclei, which add energy to the nuclear spin system. As the nuclear spins relax back to their rest energy state, they release the absorbed energy in the form of an RF signal. This RF signal (or MR signal) is detected by one or more RF coil arrays
Implementation Method 2
MRI systems also include gradient coils that produce smaller amplitude, spatially-varying magnetic fields with orthogonal axes to spatially encode the magnetic resonance (MR) signal by creating a signature resonance frequency at each location in the body
Implementation Method 3
MRI uses a powerful magnet to create a strong, uniform, static magnetic field B0. When the human body, or part of the human body, is placed in the magnetic field B0, the nuclear spins associated with the hydrogen nuclei in tissue water become polarized, wherein the magnetic moments associated with these spins become preferentially aligned along the direction of the magnetic field B0
Data Source
AI summary
Various methods and systems are provided for selecting radio frequency coil array comprising a plurality of coil elements for magnetic resonance imaging. In one embodiment, the method includes grouping the plurality of coil elements into receive elements groups (REGs) according to REGs information; generating REG sensitivity maps; determining, for each REG, signal in a region of interest (ROI) and signal in an annefact source region based on the REG sensitivity maps; selecting one or more REGs based on the signal in the ROI and the signal in the annefact source region; and scanning the ROI with the coil elements in the one or more selected REGs being activated and the coil elements not in any selected REGs being deactivated. In this way, annefact artifacts in the reconstructed image may be reduced.