MRI Apparatus Respiratory Phase Synchronization
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Solution Overview
Problem
Current MRI imaging techniques using electrocardiogram gating and respiratory movement gating in combination result in low data acquisition efficiency and prolonged imaging times, especially when the respiratory stable period is short, leading to missed data acquisition opportunities and increased body movement artifacts.
Innovation Solution
The MRI apparatus employs a respiratory movement monitoring unit to detect the start of a stable expiration period, synchronizing cardiac and respiratory phases for data acquisition, allowing for efficient data collection in two consecutive heartbeats by adjusting the timing of main measurements based on navigation echoes and electrocardiogram gating signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data is collected depending on respiratory period and heartbeat period using conventional double gating, then body movement artifact is suppressed, but data acquisition efficiency is low and imaging time is prolonged
Solution Approach 1:
The system performs preliminary detection of respiratory stable period start timing using navigation echoes before actual data acquisition. By detecting the respiratory phase in advance and storing this information, the system can immediately initiate data acquisition when the stable period begins, without waiting for conventional gating signals. This preliminary action enables efficient use of the respiratory stable period while maintaining artifact suppression.
Solution Approach 2:
The system continuously monitors respiratory movement using navigation echoes and provides real-time feedback about respiratory phase. Based on this feedback, the imaging timing is dynamically adjusted to acquire data during stable respiratory periods. The system stores respiratory phase information and uses it to control when main imaging is performed, creating a closed-loop feedback system that optimizes both efficiency and quality.
2Manufacturing precision
If main imaging is not executed when respiratory displacement deviates from threshold, then image quality is maintained, but imaging time extends due to missed acquisition opportunities
Solution Approach 1:
The system performs preliminary detection of respiratory stable period start timing using navigation echoes before actual data acquisition. By detecting the respiratory phase in advance and storing this information, the system can immediately initiate data acquisition when the stable period begins, without waiting for conventional gating signals. This preliminary action enables efficient use of the respiratory stable period while maintaining artifact suppression.
Solution Approach 2:
The system dynamically adjusts imaging timing based on real-time respiratory phase detection. Instead of using fixed threshold-based gating, the system continuously monitors respiratory displacement and adapts the imaging schedule to match the subject's actual respiratory rhythm. This dynamic approach allows data acquisition during stable periods while accommodating variations in respiratory rate and pattern.
3Reliability
If data acquisition is restricted to stable respiratory periods, then body movement artifact is reduced, but data acquisition efficiency decreases when stable period is short
Solution Approach 1:
The system performs preliminary detection of respiratory stable period start timing using navigation echoes before actual data acquisition. By detecting the respiratory phase in advance and storing this information, the system can immediately initiate data acquisition when the stable period begins, without waiting for conventional gating signals. This preliminary action enables efficient use of the respiratory stable period while maintaining artifact suppression.
Solution Approach 2:
The system continuously acquires navigation echoes to monitor respiratory phase throughout the imaging process. This continuous monitoring ensures that no stable period is missed and allows immediate transition to main imaging when stability is detected. The continuous action of navigation measurement provides uninterrupted feedback for optimizing data acquisition timing.
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 enhances data acquisition efficiency, minimizes imaging time, and reduces body movement artifacts by ensuring data is collected at optimal cardiac and respiratory phases, enabling accurate image reconstruction with reduced misregistration.
Implementation Method 1
an imaging unit 10 that collects a nuclear magnetic resonance signal generated from a subject
Data Source
AI summary
A respiratory movement is monitored during imaging to detect the start of a respiratory stable period (expiration). After an R wave is detected, it is confirmed that the respiratory movement immediately before the R wave detection transitions to the respiratory stable period, and a main measurement is performed at a timing at which a cardiac time phase and a respiratory time phase of a subject are matched with each other, to acquire image data. The cardiac time phase for acquiring the image data is fixed, and a slice position of the main measurement is adjusted by using a respiratory movement displacement acquired immediately before the cardiac time phase fixation. As a result, the image data for two heartbeats can be acquired in a respiratory period after the entrance into the stable period while suppressing an influence of body movement.