MRI Calibration Range Optimization via Spatial Segmentation
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Solution Overview
Problem
The accuracy of calibration in MRI apparatuses can be reduced due to subject disposition, leading to image quality degradation, and existing methods to improve calibration accuracy often extend examination time by requiring re-execution or wider calibration ranges.
Innovation Solution
Optimizing calibration imaging conditions by incorporating spatial information about the subject and apparatus elements, allowing for precise setting of the calibration range to ensure accurate data collection without extending examination time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the calibration range is expanded to include the entire width of the subject, then the calibration accuracy is improved, but the examination time is extended
Solution Approach 1:
The patent applies local quality by setting different calibration ranges for different regions of the subject based on their specific imaging requirements. Rather than uniformly expanding the calibration range for the entire subject, the system identifies and calibrates only the specific regions where calibration is needed, such as the examination part and surrounding areas, thereby improving calibration accuracy where necessary without extending examination time for unnecessary regions.
Solution Approach 2:
The patent segments the subject into multiple regions with different calibration requirements. The calibration range is divided into a first calibration range for the examination part and a second calibration range for other regions. This segmentation allows the system to perform targeted calibration on specific segments rather than the entire subject, resolving the contradiction between calibration accuracy and examination time.
2Measurement precision
If the calibration range is set to include the main imaging range, then the calibration coverage is improved, but subject regions outside the calibration range are not corrected leading to image quality degradation
Solution Approach 1:
The patent applies preliminary action by performing calibration imaging before main imaging to obtain calibration data for sensitivity distribution and magnetic field distribution. The system uses this preliminary calibration information to appropriately set the calibration range, ensuring that subsequent main imaging is performed with proper calibration coverage. This preliminary calibration action ensures that the calibration range is optimally set to cover necessary regions without missing subject areas that would lead to image quality degradation.
3Measurement precision
If automatic calibration is re-executed or calibration range is expanded, then the calibration accuracy is improved, but the examination time is extended
Solution Approach 1:
The patent applies partial action by performing calibration only on the necessary portions of the subject rather than the entire subject. The system determines an appropriate calibration range that covers the examination part and necessary surrounding regions, performing calibration on this partial area rather than expanding the calibration range to include the entire subject width. This partial calibration approach maintains calibration accuracy for the required regions while preserving examination efficiency.
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 the accuracy of automatic calibration, reduces redundant calibration, and improves image quality while minimizing examination time by efficiently acquiring necessary calibration data.
Implementation Method 1
The MRI apparatus applies a high-frequency magnetic field to a subject in an imaging space in which a uniform static magnetic field is generated, acquires a nuclear magnetic resonance signal generated from the subject
Implementation Method 2
The calibration items include an appearance of the subject, a transmission gain, a reception gain, a center frequency, and the like, in addition to the above-described static magnetic field distribution (B0 distribution), transmission sensitivity distribution (B1 distribution), and reception sensitivity distribution
Data Source
AI summary
An apparatus and a method can be provided to improve the accuracy of automatic calibration without extension of an examination time in an MR examination. A range of calibration performed before main imaging is determined with reference to a main imaging range and other spatial information. The spatial information consists of information for estimating an MR signal generation range, such as a subject region, a uniform magnetic field region, and a structural restriction of an apparatus, and a calibration range is determined such that a proportion of the MR signal generation range included in the calibration range is as high as possible.