MRI K-Space Sampling for High-Resolution Motion Correction
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Solution Overview
Problem
Existing magnetic resonance imaging (MRI) techniques struggle with motion artifacts, particularly from fast movements like heavy breathing, due to insufficient temporal resolution in retrospective motion correction methods, which are computationally demanding and impractical for clinical use.
Innovation Solution
Acquire additional k-space lines within the central region of k-space at regular intervals during echo trains to enable high-temporal resolution motion estimation, using a modified imaging protocol that integrates these lines into the echo train without disrupting the scan, allowing for robust and fast-converging motion correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retrospective motion correction techniques are used to correct motion artifacts after data acquisition, then motion artifacts are reduced through improved model agreement, but computational cost becomes excessively high prohibiting clinical use
Solution Approach 1:
The patent segments the k-space acquisition into multiple shots with different reordering schemes. Each shot acquires a portion of k-space lines in a specific order (e.g., linear, radial, or mixed), allowing the motion correction algorithm to work with smaller, manageable data subsets rather than the entire dataset, thereby reducing computational complexity while maintaining correction accuracy
Solution Approach 2:
The patent applies partial action by using simplified motion correction for most of the k-space data while applying full motion correction only to specific portions (e.g., central k-space lines or selected shots). This selective approach reduces the overall computational burden while still achieving effective motion artifact suppression in the final image
2Measurement precision
If motion parameters are estimated at high temporal resolution to capture fast movements, then motion correction accuracy improves, but scan time increases excessively
Solution Approach 1:
The patent implements periodic action by acquiring k-space lines in periodic reordering patterns across multiple shots. Instead of continuously increasing temporal resolution which would require denser sampling, the method uses periodic reordering of k-space line acquisition that enables motion parameter estimation at effective temporal resolution while maintaining efficient scan timing
Solution Approach 2:
The patent applies preliminary action by pre-planning and pre-ordering the k-space acquisition sequence before scanning begins. The reordering scheme is determined in advance, allowing the system to capture necessary motion information through the structured acquisition pattern itself, rather than requiring additional real-time measurements that would extend scan time
3Measurement precision
If additional k-space lines are acquired frequently to improve motion estimation, then motion parameter accuracy improves, but scan time increases
Solution Approach 1:
The patent applies local quality by acquiring additional k-space lines specifically in the central region of k-space rather than uniformly across the entire k-space. The central region contains the most critical low-frequency information for motion estimation, so concentrating additional acquisitions there improves motion parameter accuracy with minimal additional scan time compared to uniform sampling
Data Source
AI summary
A method is provided for acquiring a magnetic resonance image dataset of an object, using an imaging protocol in which several k-space lines are acquired in one echo train, wherein the echo train may include one or several sub echo trains, and wherein the imaging protocol includes a plurality of echo trains. Within the method, a set of additional k-space lines within a central region of k-space is acquired a number of times per echo train, wherein the number is greater than 1, in order to detect movement of the object during the echo train. The sets of additional k-space lines are acquired at pre-determined positions within the echo trains. The disclosure is also directed to a method for generating a motion-corrected magnetic resonance image dataset from the dataset thus acquired, a magnetic resonance imaging apparatus, and a computer program.