Gradient-Echo MRI Sampling for Motion Estimation Without Longer Scans
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Solution Overview
Problem
Existing MRI methods, such as SAMER, prolong acquisition times due to the need for additional motion guidance lines, which is particularly problematic in steady-state sequences like T2*GRE and SWI, leading to increased susceptibility to patient motion and degraded image quality.
Innovation Solution
A gradient-echo imaging protocol that inserts additional gradient echoes during the dead-time between RF excitations to acquire redundant k-space lines for motion parameter estimation, allowing for rapid and efficient motion correction without extending scan time, particularly suitable for SWI and other sequences with long echo times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional motion guidance lines are acquired using SAMER technique, then motion parameter estimation is improved, but acquisition time is prolonged
Solution Approach 1:
The patent applies preliminary action by acquiring motion guidance lines during the dead-time between RF excitations, before the main imaging data acquisition begins. This allows motion information to be gathered in advance without extending the total scan time, as the guidance lines are acquired during the inherent idle periods of the imaging sequence.
Solution Approach 2:
The patent implements periodic action by acquiring motion guidance lines at regular intervals throughout the imaging protocol, utilizing the periodic dead-time between RF excitations. This systematic periodic acquisition ensures continuous motion monitoring without disrupting the main imaging sequence, effectively resolving the time contradiction.
2Manufacturing precision
If scan time is reduced to minimize patient motion, then image quality is improved, but motion correction capability is reduced
Solution Approach 1:
The patent applies preliminary action by acquiring motion guidance lines during the dead-time between RF excitations, before the main imaging data acquisition begins. This allows motion information to be gathered in advance without extending the total scan time, as the guidance lines are acquired during the inherent idle periods of the imaging sequence.
Solution Approach 2:
The patent uses motion guidance lines as an intermediary to bridge the gap between rapid imaging and accurate motion correction. These guidance lines serve as a mediator that provides motion information without requiring additional scan time, enabling both fast imaging and reliable motion correction to coexist.
3Manufacturing precision
If retrospective motion correction is applied to multi-shot acquisitions, then motion artefacts are reduced, but computational cost increases
Solution Approach 1:
The patent applies segmentation by separating the motion estimation process from the main image reconstruction. Instead of performing complex joint optimization of motion and image parameters, the patent segments the task into two independent parts: acquiring motion guidance lines during dead-time, and then performing motion correction using these pre-acquired lines. This segmentation dramatically reduces computational complexity while maintaining motion artefact reduction.
Solution Approach 2:
The patent applies preliminary action by acquiring motion guidance lines during the dead-time between RF excitations, before the main imaging data acquisition begins. This allows motion information to be gathered in advance without extending the total scan time, as the guidance lines are acquired during the inherent idle periods of the imaging sequence.
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
Enables high-quality, motion-corrected MRI datasets with reduced scan time and improved image quality by using additional k-space lines within the imaging protocol, avoiding the need for additional scan time and maintaining diagnostic accuracy.
Implementation Method 1
k-space is sampled during the imaging protocol by using RF excitations followed by an echo time resulting in a gradient echo
Implementation Method 2
RF excitations followed by an echo time resulting in a gradient echo
Implementation Method 3
The gradient-echo imaging protocol has been amended by inserting additional gradient blips after at least some of the RF excitations, such that at least one additional gradient echo is generated
Data Source
AI summary
A method for acquiring a magnetic resonance image dataset of a field-of-view using a gradient-echo imaging protocol includes acquiring additional k-space lines within a central region of k-space at intervals throughout the imaging protocol, wherein the additional k-space lines are used for estimating motion parameters of the field-of-view. The imaging protocol has been amended by inserting additional gradient blips after at least some of the RF excitations, such that at least one additional gradient echo is generated, allowing the acquisition of at least one additional k-space line during one echo time.