Flexible Triggered Segmentation for MRI Acquisition
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Solution Overview
Problem
Conventional ECG-gated CE-MRA techniques are inefficient due to rigid trigger segmentation, which results in longer scan times and is not compatible with parallel acquisition techniques, and are affected by unpredictable ECG triggering, leading to potential contrast washout and reduced image quality.
Innovation Solution
Flexible triggered segmentation is implemented, where a k-space table is partitioned into segments, with cardiac cycle monitoring and dynamic adjustment of acquisition windows to optimize image acquisition, allowing for efficient use of acquisition time and improved cardiac motion suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If rigid trigger segmentation is used in ECG-gated CE-MRA, then cardiac motion suppression is improved, but scan time increases and acquisition efficiency decreases
Solution Approach 1:
The k-space table is divided into multiple segments that can be acquired in different cardiac phases. Instead of acquiring all k-space lines in a single rigid sequence per heartbeat, the method segments the acquisition into multiple flexible segments that can be distributed across multiple heartbeats, allowing more efficient utilization of the cardiac cycle while maintaining motion suppression.
Solution Approach 2:
The acquisition scheme transitions from a static, predetermined segmentation to a dynamic approach where the segmentation and timing are adapted based on actual cardiac cycle characteristics. The system dynamically adjusts the acquisition windows and segment distribution to match the measured R-R intervals, optimizing both motion suppression and time efficiency.
2Reliability
If rigid trigger segmentation is used, then cardiac phase synchronization is improved, but compatibility with parallel acquisition techniques is lost
Solution Approach 1:
By segmenting the k-space acquisition into multiple independent segments, the method enables parallel acquisition techniques to be applied within each segment or across segments. This segmentation allows flexible assignment of different acquisition strategies to different segments, maintaining cardiac phase synchronization while enabling parallel imaging and other advanced techniques.
Solution Approach 2:
The system changes the acquisition parameters dynamically, allowing different segments to use different acquisition strategies including parallel imaging techniques. The segmentation framework permits parameter optimization for each segment while maintaining overall cardiac phase synchronization, thus achieving both reliability and adaptability.
3Device complexity
If fixed acquisition window is used with steady R-R interval assumption, then sequence timing is simplified, but contrast timing accuracy decreases due to physiological irregularities
Solution Approach 1:
The system incorporates feedback from actual ECG trigger measurements to adjust the acquisition timing. By monitoring the actual R-R intervals and using this information to adjust the acquisition window timing, the method maintains accurate contrast timing despite physiological irregularities, while the feedback mechanism handles the complexity of timing adjustments automatically.
Solution Approach 2:
The system performs preliminary measurements of the cardiac cycle characteristics before the actual contrast-enhanced acquisition. This preliminary action allows the system to pre-calculate optimal timing parameters based on the patient's specific cardiac rhythm, ensuring accurate contrast timing when the actual acquisition begins without adding complexity during the critical contrast phase.
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 scan time, increases efficiency to over 70%, and maintains high spatial resolution, while ensuring accurate contrast timing and reduced cardiac motion, even in thoracic imaging.
Implementation Method 1
A patient's cardiac cycle is monitored using an electrical signal tracking system
Data Source
AI summary
A method for using flexible triggered segmentation to optimize magnetic resonance imaging includes partitioning a k-space table into a plurality of k-space segments, each respective k-space segment comprising one or more phase-encoding steps from a plurality of slice-encoding lines. A cardiac cycle is monitored using an electrical signal tracking system and used to trigger acquisition of the plurality of k-space segments over a plurality of acquisition windows.