Temperature Response Prediction via SAR Segment Convolution
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Solution Overview
Problem
Current methods for predicting temperature increases in biological tissues due to time-varying Specific Absorption Rate (SAR) levels are cumbersome and time-consuming, relying on SAR averaging which has limited direct relation to risk, and fail to rapidly calculate temperature changes over arbitrary time periods.
Innovation Solution
A method that predicts temperature increase by characterizing the tissue response to a single short SAR segment, using linear heat equations and convolving the temperature response with a sequence of SAR segments, allowing for rapid prediction of temperature changes without requiring specific knowledge of SAR spatial distribution or physiological parameters, assuming time-invariant parameters and linear relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SAR averaging over 10g is used to assess safety, then safety assessment can be performed, but the calculation is cumbersome and time-consuming with limited direct relation to risk
Solution Approach 1:
The patent segments the continuous SAR signal into discrete time segments and uses segment-based convolution to calculate temperature. By dividing the heating process into manageable segments and using pre-calculated temperature response functions for each segment type, the method enables rapid temperature prediction without requiring continuous complex calculations, thus reducing computation time while maintaining safety assessment accuracy
Solution Approach 2:
The patent pre-calculates temperature response functions for different SAR segment types and stores them for later use. This preliminary action allows the system to quickly retrieve and combine pre-computed responses rather than performing full temperature calculations from scratch for each new SAR scenario, significantly reducing real-time computation time while preserving reliability
2Measurement precision
If temperature increase is calculated directly for time-varying SAR levels, then direct risk assessment is possible, but the computation is complex and time-consuming
Solution Approach 1:
The patent pre-computes and stores temperature response functions for canonical SAR segments before actual use. When predicting temperature for time-varying SAR, the system simply retrieves these pre-computed responses and combines them through convolution, avoiding the need to solve complex heat diffusion equations in real-time. This maintains high temperature prediction accuracy while dramatically reducing computational complexity
Solution Approach 2:
The patent creates simplified copies of the full temperature calculation process in the form of pre-computed response functions. Instead of performing complete thermal simulations for each SAR scenario, the system uses these copied responses that capture the essential thermal behavior, achieving accurate temperature predictions with much simpler operations
3Productivity
If rapid temperature prediction is implemented for time-varying SAR, then computation time is reduced, but accuracy may be compromised
Solution Approach 1:
The patent segments the SAR signal into discrete time segments and uses segment-based convolution where the total temperature response is the sum of individual segment responses. This segmentation allows rapid calculation by avoiding full continuous simulation, while maintaining accuracy because each segment's contribution is calculated using exact analytical or pre-computed solutions rather than approximations
Solution Approach 2:
The patent maintains continuous temperature prediction capability by using overlapping segment convolutions and accumulating temperature responses continuously over time. This ensures that the rapid prediction method does not sacrifice temporal resolution or accuracy, as the continuous accumulation of segment responses captures the full thermal history and current temperature state
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
Enables accurate and rapid prediction of temperature increases during medical procedures like MRI, ensuring safety by providing conservative estimates of maximum temperature rises, significantly reducing computation time and maintaining high accuracy, especially in voxels with highest temperature increases.
Implementation Method 1
specific absorption rate ('SAR'), the rate at which energy is absorbed by tissue when exposed to a radio frequency (RF) electromagnetic field
Implementation Method 2
linear heat equations
Data Source
AI summary
After the temperature response to a single period of heating (SAR segment) is determined, temperature increases for an arbitrary timecourse of heating is determined based upon a convolution of the temperature response curve for a sequence of different SAR segments.