MR Receiving Coil Motion Tracking via Impedance Noise Analysis
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Solution Overview
Problem
Current methods for monitoring respiratory motion during MR imaging are inefficient, costly, and introduce additional hardware requirements, leading to prolonged scanning times and image artifacts.
Innovation Solution
A method that acquires noise from the receiving coil before or after each imaging repetition time, determines the main coil channels associated with the motion, sums the squares of noise amplitudes, and filters them to obtain a motion track, allowing for accurate respiratory motion monitoring without extra hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an external monitoring device is used to monitor respiratory motion, then respiratory motion can be monitored in real time, but the device configuration time increases, patient positioning time increases, and device cost increases
Solution Approach 1:
The MR imaging system's receiving coil performs self-monitoring of respiratory motion by detecting impedance changes caused by respiratory motion. The system uses its own RF coil and controller to monitor motion without requiring external monitoring devices, thereby eliminating the need for separate device configuration and patient positioning procedures
Solution Approach 2:
The receiving coil serves multiple functions: it performs both MR image acquisition and respiratory motion monitoring. The controller processes both imaging signals and motion monitoring signals, allowing the system to achieve dual functionality without additional hardware, thus reducing configuration time and complexity
2Measurement precision
If navigation echo technology with extra RF pulses and gradient pulses is applied for respiratory gating or compensation, then respiratory motion artifacts can be reduced, but scanning time is prolonged and scanning efficiency is reduced
Solution Approach 1:
The system continuously monitors respiratory motion during the entire imaging process using the receiving coil's impedance changes. This continuous monitoring allows for real-time motion tracking without interrupting the imaging sequence or requiring additional navigation echo pulses, thereby maintaining scanning efficiency while reducing artifacts
Solution Approach 2:
The controller receives real-time motion signals from the receiving coil and uses this feedback information to adjust the imaging sequence timing or apply motion compensation. This feedback mechanism enables artifact reduction without requiring extra RF pulses or gradient pulses that would prolong scanning time
3Measurement precision
If an extra pick-up coil or directional coupler is added to measure impedance for respiratory motion monitoring, then respiratory motion can be monitored, but hardware cost increases and system complexity increases
Solution Approach 1:
The receiving coil monitors respiratory motion by detecting changes in its own impedance caused by respiratory motion. The system uses its existing RF coil and controller to perform both imaging and motion monitoring functions, eliminating the need for extra pick-up coils or directional couplers and thereby reducing hardware complexity and cost
Solution Approach 2:
The receiving coil and controller are designed to perform multiple functions: MR signal reception for imaging and impedance detection for respiratory motion monitoring. This multi-functionality eliminates the need for separate monitoring hardware, reducing system complexity and device cost while maintaining monitoring capability
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 higher accuracy and lower costs by reducing image artifacts and scanning time, while avoiding the need for additional hardware, effectively monitoring respiratory motion and improving MR imaging efficiency.
Implementation Method 1
measuring an impedance of an RF coil
Data Source
AI summary
Embodiments of the present invention provide a motion monitoring method during MR imaging, comprising: acquiring a noise of a receiving coil before or after each imaging repetition time of an imaging scanning sequence; determining main coil channels associated with a motion of a scanned object in the receiving coil; determining a sum of squares of amplitudes of noises of the respective main coil channels; and filtering the sum of squares of amplitudes of noises of the main coil channels to obtain a motion track of the scanned object.