K-space Central Region Acquisition for MR Artifact Reduction
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Solution Overview
Problem
Magnetic resonance (MR) methods for acquiring three-dimensional volume segments suffer from long acquisition times, leading to movement artifacts in MR data and reconstructed images due to patient movement during data acquisition.
Innovation Solution
A method that repeatedly acquires k-space points in the middle segment of k-space, comparing and averaging data to detect and eliminate movement artifacts, and adjusting the acquisition frequency of k-space lines to prioritize the central region, where errors have a more pronounced effect, to minimize artifacts in the final MR image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional MR methods (e.g., SPACE sequence) are used to acquire three-dimensional volume segment data, then complete volumetric coverage is achieved, but acquisition time becomes excessively long leading to movement artifacts
Solution Approach 1:
The patent segments k-space into different regions (central region and peripheral regions) and applies different acquisition strategies to each segment. The central region is acquired repeatedly multiple times, while peripheral regions are acquired fewer times, creating a non-uniform sampling pattern that prioritizes the most artifact-prone areas.
Solution Approach 2:
The patent implements periodic re-acquisition of central k-space lines throughout the imaging process. By repeatedly sampling the central region at regular intervals and combining these measurements, the method periodically refreshes the most critical data points, reducing the impact of patient movement during the overall acquisition.
2Reliability
If the entire k-space is acquired uniformly, then complete data coverage is obtained, but movement artifacts affect all regions equally including the central region
Solution Approach 1:
The patent applies different acquisition qualities and frequencies to different regions of k-space. The central region receives enhanced attention with multiple repeated acquisitions and higher sampling density, while peripheral regions use standard sampling. This local differentiation ensures that the most critical regions (central k-space) have superior data quality and are more resistant to movement artifacts.
Solution Approach 2:
The method incorporates feedback by comparing repeatedly acquired central k-space measurements and using averaging or selection algorithms to identify and eliminate inconsistent data points. This feedback mechanism detects movement artifacts through comparison and selectively discards or corrects affected measurements, improving overall data consistency.
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 significantly reduces movement artifacts in MR images by frequently acquiring k-space lines in the central region, ensuring more stable and accurate MR data acquisition and image reconstruction.
Implementation Method 1
The three-dimensional volume segment is excited with an RF excitation pulse
Implementation Method 2
Switch a refocusing pulse. Switch a first phase coding gradient along a first direction and a second phase coding gradient along a second direction. Switch an additional magnetic field gradient in a third direction
Data Source
AI summary
Acquisition of magnetic resonance (MR) data in a predetermined three-dimensional volume segment of an examination subject with an MR apparatus proceeds by the volume segment being excited with an RF excitation pulse, and repeated, temporally sequential implementation of the following in order to respectively read out an echo train:Switch a refocusing pulse.Switch a first phase coding gradient in a first direction and a second phase coding gradient in a second direction.Switch an additional magnetic field gradient for spatial coding in a third direction which is perpendicular to the first direction and the second direction,wherein the MR data of a k-space line are read out while the additional magnetic field gradient is switched.Every k-space line corresponds to a line of k-space that corresponds to the volume segment. At least one k-space line is read out repeatedly in a middle segment of k-space.