MRI Scanning-Condition Recalculation for FOV Adjustments
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Solution Overview
Problem
Magnetic resonance imaging (MRI) systems face challenges in maintaining a constant Signal-to-Noise (SN) ratio when adjusting the Field Of View (FOV) for varying subject sizes, requiring skilled operators and increasing examination time due to the complexity of determining necessary parameter changes.
Innovation Solution
An MRI apparatus with a scanning-condition recalculating unit that adjusts other scanning parameters to maintain or exceed the original SN ratio when the FOV is changed, including algorithms to recalculate parameters based on FOV changes in readout, phase encoding, and slice directions, ensuring stable image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the FOV is adjusted manually by an operator to match subject size, then the imaging coverage is optimized, but the operation becomes time-consuming and requires skilled expertise
Solution Approach 1:
The system automatically measures the subject size using the positioning device and autonomously calculates the appropriate FOV and scanning parameters without requiring manual intervention or skilled operator expertise, thereby reducing examination time while maintaining adaptability to different subject sizes
Solution Approach 2:
The system automatically changes scanning parameters (FOV, matrix size, voxel dimensions) based on the measured subject size to maintain optimal imaging conditions, eliminating the need for manual parameter adjustment and reducing the time required for setup
2Adaptability or versatility
If the FOV is changed to match subject size, then the imaging coverage is optimized, but the SN ratio changes and requires manual parameter correction
Solution Approach 1:
The system automatically calculates and applies the necessary parameter corrections to maintain constant SN ratio when FOV changes, eliminating the need for manual correction by the operator. The recalculation unit autonomously determines the appropriate scanning parameters based on the measured subject size and desired SN ratio
Solution Approach 2:
The system uses feedback from the positioning device measurements to automatically adjust scanning parameters. The measured subject size feeds back into the recalculation unit, which then determines the appropriate FOV and other parameters to maintain constant SN ratio, creating a closed-loop system that eliminates manual intervention
3Ease of operation
If default scanning conditions are used for all subjects, then the operation is simplified, but the SN ratio becomes unstable due to size variations
Solution Approach 1:
The system transitions from static default scanning conditions to dynamic parameter adjustment. The scanning parameters are automatically adjusted in real-time based on the measured subject size, allowing the system to adapt to different subject dimensions while maintaining stable SN ratio and image quality
Solution Approach 2:
The system automatically changes scanning parameters (FOV, matrix size, voxel dimensions, and other related parameters) based on the measured subject size to maintain optimal imaging conditions and stable SN ratio across different subject dimensions, eliminating the need for manual parameter adjustment
4Measurement precision
If manual FOV adjustment is performed to avoid aliasing, then the imaging accuracy is improved, but the examination time increases
Solution Approach 1:
The system automatically measures subject size using the positioning device and autonomously calculates the appropriate FOV to prevent aliasing, eliminating the need for manual measurement and adjustment. This automated approach maintains imaging accuracy while significantly reducing the time required for setup
Solution Approach 2:
The system performs preliminary measurement of the subject size using the positioning device before the actual scanning begins. Based on this pre-measurement, the system pre-calculates the appropriate FOV and scanning parameters, allowing the scanner to start immediately without time-consuming manual adjustment during the examination
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
Automatically maintains a consistent SN ratio during FOV adjustments, simplifying the process for operators and reducing examination time, even for inexperienced users, by recalculating and notifying the necessary scanning conditions.
Implementation Method 1
A magnetic resonance imaging method used by a magnetic resonance imaging apparatus is a method of acquiring chemical and physical microscopic information about a substance by using a magnetic resonance phenomenon. The magnetic resonance phenomenon is a phenomenon that when being placed in a magnetic field, an aggregation of subject nuclear spins resonates with a radio-frequency magnetic field in which each atomic nucleus spins at a particular frequency (resonance frequency) responding to its own unique magnetic moment and an existing magnetic field, and generates a signal (magnetic resonance signal) in a relaxation process.
Data Source
AI summary
A Signal-to-Noise (SN) ratio maintained scanning-condition recalculating unit re-sets a value of a scanning parameter other than an SN ratio included in scanning conditions when the size of a Field Of View (FOV) to be set for a scan is changed, so as to make the SN ratio of an image to be taken under after-change scanning conditions equal to or larger than the SN ratio of an image assumed to be taken under before-change scanning conditions. A scanning-condition edit/scan positioning unit then sets scanning conditions based on the value of the scanning parameter recalculated by the scanning-condition recalculating unit.