MRI SAR Estimation Using RF Shimming Hotspot Selection
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Solution Overview
Problem
Traditional methods for determining the specific absorption rate (SAR) in magnetic resonance imaging (MRI) are inefficient and computationally intensive due to the complexity of human body structures and RF field inhomogeneity, especially at higher magnetic field strengths, making real-time adaptations challenging.
Innovation Solution
A method involving obtaining scanning information and a target set of sensitivity distribution matrices for selected local hotspots, using RF shimming field parameters to estimate SAR, reducing computational load by focusing on key hotspots rather than comprehensive point calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional comprehensive point calculation method is used for SAR determination, then measurement precision is improved, but computational complexity increases and computational efficiency decreases
Solution Approach 1:
The patent segments the continuous body model into discrete voxel grid points, and further identifies only the critical local hotspots among these voxels for SAR calculation. This segmentation approach transforms the problem from calculating SAR at all possible points to focusing on segmented critical regions, reducing computational complexity while maintaining accuracy.
Solution Approach 2:
The patent extracts and identifies local hotspots from the comprehensive set of all voxel positions in the body model. By taking out only the critical hotspot positions where SAR is most likely to be elevated, the method eliminates unnecessary calculations at non-critical positions, thereby reducing computational complexity while preserving measurement precision.
2Measurement precision
If traditional comprehensive point calculation method is used for SAR determination, then measurement precision is improved, but productivity decreases
Solution Approach 1:
The patent performs preliminary identification of local hotspots before conducting the full SAR calculation. By pre-identifying the critical regions where SAR is most likely to be elevated, the method prepares the calculation in advance to focus only on these regions, improving computational efficiency without sacrificing accuracy.
Solution Approach 2:
Instead of performing calculations at all possible voxel positions (excessive action), the patent performs calculations only at the identified local hotspots (partial action). This partial action approach is sufficient to determine SAR accuracy since hotspots represent the critical regions, thereby improving productivity while maintaining measurement precision.
3Adaptability or versatility
If RF shimming field parameters are increased to satisfy clinical scanning requirements at higher magnetic field strengths, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent implements a dynamic approach where the number and positions of local hotspots are determined based on the specific scanning conditions, target object characteristics, and magnetic field strength. This dynamic adaptation allows the method to adjust to different clinical requirements without requiring a fixed, overly complex set of RF shimming parameters for all scenarios.
Solution Approach 2:
The patent changes the parameters used for SAR determination by focusing on local hotspot positions and sensitivity distribution matrices specific to each scanning condition. By changing from a comprehensive fixed-parameter approach to a conditional parameter selection approach, the method achieves adaptability to different scanning conditions while managing complexity.
Data Source
AI summary
A method for determining a specific absorption rate (SAR) is provided. The method includes a scanning information of a target object; obtaining a target set matching the scanning information of the target object; and determining an SAR estimated value for the target object based on a target RF shimming field parameter of an RF coil and the target set.