Magnetic Resonance Stimulation Simulation via Gradient Change Detection
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Solution Overview
Problem
Current methods for simulating electrical stimulation in magnetic resonance systems are inefficient due to the need to calculate stimulation values at every time point during imaging sequences, which is computationally intensive and time-consuming, especially when many magnetic field gradients remain constant or have constant derivatives over long periods.
Innovation Solution
The method restricts simulation to change time points where the time derivative of the magnetic field gradients changes, using a simplified formula to calculate stimulation values only at these points, significantly reducing the number of simulation steps and accelerating the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stimulation simulation is performed at every time point during imaging sequences, then measurement safety is ensured, but calculation time increases significantly
Solution Approach 1:
The patent segments the continuous time domain into discrete time points where gradient changes occur. Instead of calculating stimulation values at every possible time point, the method identifies and calculates only at specific change time points where gradient characteristics actually change, thereby reducing computational burden while maintaining safety assessment accuracy.
Solution Approach 2:
The patent extracts only the relevant time points (change time points) from the complete time sequence for stimulation calculation. By taking out only those specific moments when gradient changes occur and performing stimulation simulation exclusively at these extracted points, the method eliminates redundant calculations at time points where gradients remain constant.
2Reliability
If stimulation simulation is performed across the entire time characteristic of the imaging sequence, then comprehensive safety assessment is achieved, but computational complexity increases
Solution Approach 1:
The patent divides the imaging sequence time characteristic into multiple segments separated by change time points. Within each segment where gradient characteristics remain constant, no additional stimulation calculations are performed. This segmentation approach maintains comprehensive safety assessment by covering all change points while reducing computational complexity by eliminating redundant calculations within constant-gradient segments.
Solution Approach 2:
The patent performs stimulation simulation at a partial set of time points (only change time points) rather than at all possible time points. This partial action is sufficient to ensure safety because stimulation effects only change when gradient characteristics change, making calculations at intermediate constant-gradient time points unnecessary.
3Measurement precision
If iteration-based convolution filtering is used for stimulation calculation, then accurate stimulation values are obtained, but processing speed decreases
Solution Approach 1:
The patent performs preliminary identification of change time points before executing the iterative convolution filtering process. By pre-determining which time points require calculation based on gradient change detection, the method prepares the input data structure in advance, allowing the subsequent iterative filtering to operate efficiently only on necessary time points rather than processing the entire time sequence.
Data Source
AI summary
The disclosure relates to simulating an electrical stimulation during an examination of an examination object, in which the examination object is examined in a MR system to create a MR image using an imaging sequence, where a time characteristic of at least one magnetic field gradient used during the imaging sequence is determined, a time derivative of the time characteristic of the at least one magnetic field gradient is determined, and change time points at which the value of the time derivative changes are determined. The simulation of the electrical stimulation for the imaging sequence is performed, wherein the simulation is restricted to the determined change time points.