MRI K-Space Segmentation for Artifact Suppression
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Solution Overview
Problem
Conventional magnetic resonance echo plane imaging (EPI) is prone to Nyquist artifacts and acceleration artifacts, which are difficult to suppress simultaneously, and existing methods like MUSE struggle to eliminate Nyquist artifacts effectively.
Innovation Solution
The method involves acquiring k-space data sets using multiple sets of imaging sequences with pre-dephasing gradient pulses and phase encoding gradients, where the pre-dephasing gradient pulses have a standard area difference, and processing these data sets using a multiplexed sensitivity encoding algorithm to obtain a magnetic resonance image, effectively suppressing both Nyquist and acceleration artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional echo plane imaging (EPI) is used for fast imaging, then imaging speed is improved, but Nyquist artifacts appear in the images
Solution Approach 1:
The patent divides the k-space acquisition into multiple segments using multiple imaging sequences, each acquiring a portion of k-space. This segmentation allows for better control of phase encoding gradients and reduces the accumulation of errors that cause Nyquist artifacts, while maintaining the fast imaging capability of EPI.
Solution Approach 2:
The patent modifies the area of pre-dephasing gradient pulses in a systematic way across multiple imaging sequences. By changing the gradient pulse parameters (specifically the area) in a controlled manner, the method corrects phase variations that lead to Nyquist artifacts while preserving the fast imaging advantage.
2Productivity
If parallel imaging acceleration technique is applied in EPI, then imaging speed is improved, but acceleration artifacts appear in edge regions of images
Solution Approach 1:
The patent segments the k-space acquisition across multiple imaging sequences and applies parallel imaging techniques to each segment. This segmentation strategy distributes the acceleration artifacts across different regions and allows for their suppression through coherent combination, while maintaining overall imaging speed improvement.
Solution Approach 2:
The patent uses coil sensitivity information as feedback to correctly combine the segmented k-space data sets. This feedback mechanism allows for the suppression of acceleration artifacts by properly weighting and combining signals from different coil elements, while preserving the speed benefits of parallel imaging.
3Measurement precision
If MUSE method is used to resolve phase variation and parallel acceleration artifacts, then parallel imaging quality is improved, but Nyquist artifacts in images cannot be eliminated
Solution Approach 1:
The patent extends the MUSE method by systematically varying the area of pre-dephasing gradient pulses across multiple imaging sequences. This parameter change strategy specifically targets and corrects the phase variations that cause Nyquist artifacts, while maintaining the improved parallel imaging quality achieved by MUSE.
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 attenuates artifacts in the resulting MR images, providing improved suppression of Nyquist and acceleration artifacts, leading to enhanced image quality.
Implementation Method 1
magnetic resonance imaging (MRI) system and method
Implementation Method 2
each set of imaging sequences including a pre-dephasing gradient pulse and a plurality of phase encoding gradients applied after the pre-dephasing gradient pulse
Data Source
AI summary
A magnetic resonance imaging method, a magnetic resonance imaging system, and a computer-readable storage medium are provided. The magnetic resonance imaging method comprises: acquiring a plurality of portions of a k-space by using a plurality of sets of imaging sequences to obtain a plurality of k-space data sets, each set of imaging sequences comprising a pre-dephasing gradient pulse and a plurality of phase encoding gradients applied after the pre-dephasing gradient pulse, wherein the pre-dephasing gradient pulses in the plurality of sets of imaging sequences have a standard area difference in order when sorted according to the sizes of area values, and the standard area difference is 2/N of the area of any phase encoding gradient, where N is the number of sets of the plurality of sets of imaging sequences; respectively reconstructing a magnetic resonance image from each of the plurality of k-space data sets; and processing the plurality of k-space data sets to obtain a magnetic resonance image.