Cardiac T1-Mapping Pulse Sequence With Decoupled Trigger Timing
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Solution Overview
Problem
Cardiac motion constraints limit the range of delay times for T1 mapping in MRI, particularly in cardiac monitoring techniques like PPG, leading to reduced precision in T1 quantification due to inherent latencies between trigger signals and cardiac events.
Innovation Solution
A medical system and method that decouples the timing of preparatory pulses from k-space acquisitions using cardiac phase data, allowing for a broader range of T1 delay times by performing k-space data acquisition at fixed intervals relative to cardiac contractions, enabling precise T1 mapping even with significant latency in cardiac monitoring systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cardiac monitoring techniques are integrated into timing strategies to align k-space data acquisition with specific events in the cardiac cycle, then motion artifacts are reduced, but the range of available delay times is limited due to inherent latencies between trigger signals and cardiac events
Solution Approach 1:
The pulse sequence is divided into multiple independently configurable segments (preparatory pulse segments and k-space acquisition segments) that can be separately timed. Each segment can be positioned at different delay times relative to trigger signals, allowing the system to achieve both precise cardiac event alignment and a broad range of T1 delay times by independently adjusting the timing of each segment.
2Measurement precision
If the range of delay times is expanded to improve T1 quantification precision, then T1 mapping accuracy is improved, but time constraints due to cardiac motion become more difficult to manage
Solution Approach 1:
The pulse sequence employs dynamic timing adjustment where the delay times between preparatory pulses and k-space acquisitions are continuously optimized based on real-time cardiac motion phase information. The system adaptively selects from multiple possible delay time configurations to achieve both expanded T1 delay range and maintained cardiac motion synchronization, resolving the contradiction between precision and complexity.
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
Enhances the accuracy and flexibility of T1 mapping by broadening the range of achievable T1 delay times, improving the fit to relaxation models and reducing motion artifacts, especially in systems with high latency, such as PPG-based cardiac monitoring.
Implementation Method 1
cardiac T1 mapping is an essential technique for detecting tissue abnormalities that affect T1 relaxation times
Implementation Method 2
In magnetic resonance imaging (MRI), cardiac T1 mapping is an essential technique
Implementation Method 3
cardiac monitoring techniques such as photoplethysmography (PPG) due to the inherent latencies between the trigger signal and the event in the corresponding event in the cardiac cycle
Data Source
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AI summary
The invention provides for a medical system, a method of operating thereof and a computer program. The system comprises a magnetic resonance system (200) and a cardiac monitoring system (110) capturing cardiac phase data. A memory (320) holds machine executable instructions (330) and pulse sequence commands (340) causing magnetic resonance system (200) to acquire myocardial k-space data. The commands comprise at least one preparatory pulse portion (130) and multiple k-space acquisition portions (140). Executing instructions (330), computational system (302) processes cardiac phase data, identifies trigger signals (150) and causes data collection. A first preparatory pulse portion (131) follows a first k-space acquisition portion (141) after a first trigger signal (151) which occurs at a fixed acquisition delay (160) after the trigger. A second k-space acquisition portion (142) follows the pulse and a second trigger signal (152), the preparatory delay (170) between pulse and second acquisition exceeds the fixed acquisition delay.