Cardiac Motion Corrected MR Exam Using Deformable Registration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Coronary magnetic resonance angiography (MRA) faces challenges due to residual cardiac respiratory motion artifacts, leading to diagnostic inaccuracy and scan failures, with existing motion suppression strategies being vulnerable to motion pattern variations, prolonged and unpredictable scan times, operator dependency, and non-isotropic spatial resolution.
Innovation Solution
A method involving a 4D continuous radial acquisition scheme without ECG gating or breath-holding, using an ungated, spoiled gradient echo acquisition with golden-angle radial trajectory and water-selective excitation pulses, followed by respiratory motion-corrected reconstruction and non-rigid motion correction to compensate for cardiac and respiratory deformations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional motion suppression strategies are used, then cardiac and respiratory motion artifacts are suppressed, but scan time becomes prolonged and unpredictable
Solution Approach 1:
The system performs preliminary motion tracking during the imaging acquisition by continuously monitoring positional changes of the coronary vessels. This motion information is then used in real-time to adjust the imaging parameters and compensate for motion artifacts, eliminating the need for prolonged post-acquisition processing and retrospective gating strategies that extend scan time.
Solution Approach 2:
The patent implements continuous motion tracking and compensation throughout the entire imaging process, rather than using discrete gating windows or repeated acquisitions. This continuous approach maintains constant motion suppression without the time losses associated with gate rejection or repeated scans, keeping the useful imaging action uninterrupted.
2Reliability
If conventional motion suppression strategies are used, then motion artifacts are reduced, but the system becomes operator dependent
Solution Approach 1:
The system performs automatic motion tracking and compensation without requiring operator intervention. The coronary vessels themselves serve as the tracking target, and the system automatically extracts motion information from the imaging data, eliminating the need for operators to manually place landmarks or adjust gating parameters.
Solution Approach 2:
The system dynamically adjusts imaging parameters such as timing, trajectory, and acquisition windows based on real-time motion measurements. This automatic parameter adaptation replaces manual operator adjustments with algorithm-driven optimization, reducing operator dependency while maintaining motion suppression effectiveness.
3Reliability
If conventional motion suppression strategies are used, then motion artifacts are suppressed, but the system becomes vulnerable to motion pattern variations
Solution Approach 1:
The system employs dynamic motion tracking that continuously adapts to changing motion patterns during the scan. By monitoring actual vessel motion in real-time and adjusting compensation parameters accordingly, the system remains effective regardless of whether the patient exhibits regular sinus rhythm, arrhythmia, or variable breathing patterns, unlike fixed gating strategies that assume predictable motion.
Solution Approach 2:
The patent implements a feedback loop where motion information extracted from imaging data is fed back to adjust subsequent acquisition parameters. This closed-loop control allows the system to automatically adapt to motion pattern variations, maintaining artifact suppression effectiveness across different physiological conditions without requiring operator intervention or protocol modification.
4Reliability
If conventional motion suppression strategies are used, then motion artifacts are reduced, but spatial resolution becomes non-isotropic with poor resolution along the superior-inferior direction
Solution Approach 1:
The patent employs asymmetric motion compensation that applies different correction strategies along different anatomical axes. By recognizing that superior-inferior motion differs from left-right and anterior-posterior motion, the system applies targeted compensation specific to each direction, maintaining isotropic resolution rather than the degraded performance of uniform gating approaches.
Solution Approach 2:
The system performs preliminary motion characterization along all three spatial axes before reconstruction, identifying superior-inferior motion patterns specifically. This allows for targeted resolution of the anisotropy problem by applying appropriate compensation in the superior-inferior direction, improving resolution where conventional methods fail most severely.
Data Source
AI summary
In various embodiments, the present invention teaches methods and related systems for imaging the coronary arteries in high spatiotemporal resolution for the assessment of coronary stenosis. In some embodiments, the method teaches the use of a 3D radial k-space trajectory, continuous acquisition, retrospective cardiac and respiratory self-gating, and non-rigid cardiac and respiratory motion correction to reconstruct any arbitrary cardiac phase with minimal motion artifacts and high image quality.