SAR Value Acquisition in MRI via RF Field Mapping
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Solution Overview
Problem
Current MRI technologies face challenges in accurately measuring Specific Absorption Rate (SAR) values in human tissues during ultra-high-field magnetic resonance imaging, leading to potential thermal damage and imaging quality issues due to uneven RF energy deposition.
Innovation Solution
A method and system for acquiring SAR values by mapping the distribution data of RF coil transmission fields to RF electric fields, using a trained prediction model to adjust channel weights in real-time, ensuring accurate and safe SAR distribution during MRI examinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If ultra-high-field magnetic resonance is used to improve signal-to-noise ratio and imaging quality, then imaging quality is improved, but RF energy deposition in human tissues increases causing safety issues
Solution Approach 1:
The RF transmitter coil is divided into multiple channels, each with independent control. This segmentation allows selective adjustment of RF energy distribution across different body regions, enabling high signal-to-noise ratio imaging while controlling local RF energy deposition and SAR values within safety limits.
Solution Approach 2:
The system dynamically adjusts RF transmission parameters including amplitude, phase, and frequency for each channel based on real-time SAR calculations. By changing these parameters, the system maintains optimal imaging quality while ensuring RF energy deposition remains within safe thresholds.
2Stability of the object's composition
If multi-channel parallel transmission is used to optimize RF field and solve uneven image signals, then image uniformity is improved, but measurement of local SAR values becomes more complex
Solution Approach 1:
The system replaces complex physical SAR measurement devices with computational methods. By using trained prediction models that process RF coil transmission field data to estimate SAR values, the system achieves accurate local SAR measurement without additional invasive sensors or complex measurement hardware.
Solution Approach 2:
The system creates a virtual model of SAR distribution by training prediction models on simulation data. This digital copy of the SAR field allows accurate estimation of local SAR values from easily measurable RF coil transmission field data, avoiding direct complex measurement.
3Reliability
If real-time SAR value determination is implemented to ensure patient safety, then safety is improved, but system complexity and computational requirements increase
Solution Approach 1:
Prediction models are trained in advance using comprehensive simulation data covering various anatomies and scanning conditions. This preliminary training allows the system to perform rapid real-time SAR estimation during actual scans without performing complex calculations, reducing computational burden while maintaining high safety standards.
Solution Approach 2:
The system introduces prediction models as intermediaries between RF transmission control and SAR assessment. These models translate easily measurable RF coil transmission field data into accurate SAR estimates, simplifying the overall system architecture while enabling real-time safety monitoring.
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 real-time, accurate determination of SAR values, improving imaging quality and ensuring patient safety by optimizing RF energy distribution across channels.
Implementation Method 1
the radio frequency (RF) energy deposition in human tissues is also increased accordingly, thus causing insecurity for the test person
Implementation Method 2
the wavelength of the electromagnetic wave inside the human body becomes shorter as the frequency increases
Data Source
AI summary
A specific absorption rate (SAR) value acquisition method in magnetic resonance imaging includes acquiring a mapping relation between distribution data of radio frequency (RF) coil transmission field of each channel of an RF transmitter coil and distribution data of RF electric field of each channel of the RF transmitter coil, obtaining a mapping relation set, acquiring first distribution data of RF coil transmission field of each channel during an examination of a test person, determining first distribution data of RF electric field of each channel during the examination of the test person according to the first distribution data of RF coil transmission field of each channel and the mapping relation set, adjusting a weight of each channel according to the first distribution data of RF electric field of each channel acquired during the examination of the test person, and determining a distribution of SAR values of the test person.