MRI Labeling Pulse Timing Synchronization with Cardiac Cycle
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Solution Overview
Problem
Current magnetic resonance imaging (MRI) methods for observing the dynamic state of blood or cerebrospinal fluid face challenges such as signal value changes due to varying inversion times, difficulty in visualizing cerebrospinal fluid due to lower cardiac phase correlation, limited labeling region perspectives, unclear lesion positioning, and the need for clinical knowledge to set imaging conditions.
Innovation Solution
A magnetic resonance imaging apparatus and method that applies a labeling pulse to invert spins within a designated region, collecting echo signals with variations in inversion time while maintaining a constant time from a biological reference signal, allowing for synchronized imaging with pulsation and improved visualization of moving materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If inversion time TI is varied to observe dynamic state of moving material, then motion observation capability is improved, but signal value stability deteriorates due to flow velocity changes
Solution Approach 1:
The system uses ECG signal feedback to dynamically adjust the labeling pulse timing. By detecting the R-wave peak and calculating the time to the diastolic phase, the system automatically synchronizes the inversion time TI with the cardiac cycle, ensuring stable signal values while maintaining motion observation capability
Solution Approach 2:
The system changes the timing parameter of the labeling pulse based on the inversion time TI and cardiac phase. By adjusting when the labeling pulse is applied relative to the ECG reference signal, the system optimizes both motion visualization and signal stability
2Reliability
If labeling pulse timing is fixed relative to ECG reference, then synchronization with pulsation is improved, but adaptability to different inversion times deteriorates
Solution Approach 1:
The system dynamically adjusts the labeling pulse timing based on the selected inversion time TI. Instead of using a fixed delay, the calculation unit computes the optimal timing as (TI - TDseq) to maintain synchronization with the diastolic phase while adapting to different inversion time requirements
3Difficulty of detecting and measuring
If multiple images are taken with different inversion times to observe dynamic state, then motion visualization is improved, but imaging time increases
Solution Approach 1:
The system uses periodic ECG-triggered imaging sequences where multiple images are acquired at different inversion times within each cardiac cycle. This allows motion visualization through varying TI while maintaining efficient timing based on the natural periodicity of the cardiac cycle
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 provides stable visualization of signal changes with inversion time differences, enhances synchronization with pulsation, offers multi-dimensional motion observation, simplifies labeling region setting, and facilitates easier imaging condition setup, reducing artifacts and improving image quality.
Implementation Method 1
A magnetic resonance imaging apparatus generates a magnetic resonance image based on an echo signal regarding a spin included in an imaging region of a subject
Data Source
AI summary
A magnetic resonance imaging apparatus includes an imaging unit which applies a labeling pulse to invert a spin included in a labeling region within part of a imaging region and then collects a echo signal from a time point when an inversion time has passed from the application of the labeling pulse, and a control unit, the control unit controlling the imaging unit so that the echo signal in the imaging region is collected a plurality of times with variations in the inversion time, the control unit also controlling the imaging unit so that a time ranging from a reference time point within a biological signal obtained from a subject to the application of the labeling pulse is a time determined in accordance with the inversion time.