CLAWS MRI Adaptive Windowing for Motion Artifact Reduction
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Solution Overview
Problem
Current MRI techniques face inefficiencies and motion artifacts due to cyclic movements in subjects, such as breathing and heartbeats, which hinder the acquisition of high-quality images within a reasonable scan time, especially in thoracic and cardiac imaging.
Innovation Solution
The ContinuousLy Adaptive Windowing Strategy (CLAWS) method, which dynamically adjusts the acquisition order of ky lines based on the object's position and previously collected data, allowing for rapid image reconstruction and reduced acceptance window, ensuring optimal scan termination regardless of respiratory patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If navigator acceptance imaging methods are used to address cyclic motion, then motion artifact reduction is improved, but scan efficiency deteriorates due to loss from changes in breathing pattern
Solution Approach 1:
The patent implements dynamic adjustment of the acceptance window based on the subject's breathing pattern. The system continuously monitors navigator echo data to detect changes in respiratory phase and dynamically modifies the acceptance window parameters accordingly, allowing the imaging system to adapt to cyclic motion variations while maintaining scan efficiency.
Solution Approach 2:
The system uses navigator echoes to provide real-time feedback on the subject's breathing phase and position. This feedback is processed to determine whether acquired k-space data falls within the acceptance window, and the acceptance window parameters are adjusted based on this feedback, creating a closed-loop control system that balances motion artifact reduction with scan efficiency.
2Reliability
If PAWS technique with phase ordering is used, then motion artifact reduction is improved, but image availability deteriorates as images are only available once enough data is acquired within the specified range
Solution Approach 1:
The patent implements a progressive image reconstruction approach where images are reconstructed and made available as soon as sufficient data is acquired within the acceptance window, rather than waiting for complete k-space coverage. This allows partial images to be available earlier, reducing the loss of time while maintaining motion artifact reduction through continued data acquisition and window adjustment.
Solution Approach 2:
The system performs preliminary assessment of the breathing pattern using initial navigator echoes to establish baseline acceptance window parameters before full image acquisition begins. This preliminary action allows the system to be prepared to reconstruct images as soon as adequate data is collected, reducing delays in image availability.
3Adaptability or versatility
If automatic sampling strategies are used to treat all window positions with equal importance, then adaptability to breathing changes is improved, but scan termination time deteriorates as optimal termination cannot be achieved
Solution Approach 1:
The patent assigns different weights or priorities to different regions of the acceptance window based on their importance for the specific imaging task. Rather than treating all window positions with equal importance, the system can emphasize critical regions while allowing less critical regions to be acquired later or with reduced priority, enabling optimal scan termination when sufficient data is acquired in the most important regions.
Solution Approach 2:
The system dynamically changes the acceptance window parameters (such as window size, position, and weighting) based on the detected breathing pattern and imaging requirements. This allows the system to adapt to breathing changes while also optimizing for efficient scan termination by adjusting parameters to prioritize acquisition of the most critical k-space data.
4Adaptability or versatility
If DVA algorithm is used to acquire whole image before limiting respiratory motion, then flexibility in scan termination is improved, but motion artifact reduction deteriorates in subjects with variable respiratory pattern
Solution Approach 1:
The patent implements dynamic adjustment of the acceptance window based on the subject's breathing pattern. The system continuously monitors navigator echo data to detect changes in respiratory phase and dynamically modifies the acceptance window parameters accordingly, allowing the imaging system to adapt to cyclic motion variations while maintaining scan efficiency.
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
CLAWS enables rapid and reliable image acquisition with improved quality by adaptively selecting ky lines for acquisition, reducing the acceptance window and allowing for early image creation and termination at optimal scan time, even with variable respiratory patterns.
Implementation Method 1
MRI images are predominantly formed by the measurement of radio frequency signal emission during proton spin relaxation following an excitation signal to protons located in a magnetic field
Implementation Method 2
protons located in a magnetic field
Implementation Method 3
The use of magnetic field gradients allows spatially encoded data to be acquired to form an image
Data Source
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AI summary
A method of producing an MRI image of an object in cyclic motion by acquiring data in k-space according to the measured position of the object, and an analysis of data previously acquired. The invention also provides a magnetic resonance imaging heart monitor configured to use the method.