Multi-Coil Shim Insert Geometrical Parameter Determination
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Solution Overview
Problem
Current magnetic resonance (MR) shimming methods with multi-coil shim inserts face challenges due to variable coil positions and orientations, leading to inaccurate field corrections and increased computational and scanning times, as they require extensive field mapping and storage, which is time-consuming and inefficient.
Innovation Solution
Determine the geometrical parameters of individual magnetic coils within the shim insert, such as positions and orientations, to calculate optimal shim currents using digital models or neural networks, reducing the need for extensive field mapping and allowing for real-time adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If extensive field mapping is performed to determine magnetic field distribution of shim coils, then shimming accuracy is improved, but scanning time and computational time increase significantly
Solution Approach 1:
The patent creates a digital model (copy) of the shim insert that replicates its geometrical parameters and magnetic field generation characteristics. This digital twin allows virtual field mapping and optimization without requiring physical measurement of each coil configuration, dramatically reducing scanning time while maintaining shimming accuracy.
Solution Approach 2:
The patent performs field mapping and optimization in advance by measuring geometrical parameters of the shim insert and pre-calculating optimal shim currents for various imaging scenarios. This preliminary characterization stored in the digital model eliminates the need for time-consuming field mapping during actual scanning procedures.
2Measurement precision
If field mapping data for each shim coil is stored in memory, then shimming accuracy is improved, but computer memory requirements and computational complexity increase
Solution Approach 1:
Instead of storing extensive field mapping data for each coil, the patent stores a compact digital model containing geometrical parameters of the shim insert. This model can generate magnetic field distributions on-demand through simulation, replacing large data storage requirements with compact parametric representations.
Solution Approach 2:
The patent extracts only the essential geometrical parameters of the shim insert from the complete field mapping data. By separating the fundamental geometric characteristics from the derived field distribution data, the system maintains shimming accuracy while minimizing storage and computational requirements.
3Adaptability or versatility
If shim coils are made flexible to wrap around the subject, then adaptability is improved, but position stability deteriorates as coils may move during measurement
Solution Approach 1:
The patent measures the geometrical parameters of the flexible shim insert and its coils before the actual MR measurement. By capturing the position and configuration of each coil in advance, the system creates an accurate digital representation that accounts for the flexible insert's actual state, ensuring stable and accurate shimming despite the coils' flexibility.
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 minimizes storage requirements, accelerates computation and scanning times, and enables accurate, real-time shimming by using geometrical parameters to generate customizable magnetic field corrections without the need for extensive field mapping, improving the precision and efficiency of MR data acquisition.
Implementation Method 1
a shim insert comprising several magnetic coils is placed inside a bore of the magnetic resonance apparatus
Implementation Method 2
an inhomogeneity of a magnetic field, that is essentially constant, is corrected
Data Source
Figure 1~2
Figure 3
AI summary
In summary, an MR arrangement (1) and a method to shim a magnetic field inside an MR apparatus (2) using a multi-coil shim insert (3) is described. After placing the shim insert (3) inside the bore (14) of the MR apparatus (2), geometrical parameters of the individual coils (4) of the shim insert (3) are determined.