MR Thermometry Region Segmentation for Motion Artifacts
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Solution Overview
Problem
Current magnetic resonance thermometry techniques face challenges in achieving precise temperature measurements due to limitations in imaging different regions, particularly with periodic movements and spatial phase coherence issues, which hinder the application of reference-based and reference-free methods.
Innovation Solution
A method that acquires MR data at two points in time to determine temperature-induced phase shifts, allowing for the use of reference-based thermometry in one region and reference-free thermometry in another, with adjacent regions serving as reference phases to improve precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference-based MR thermometry is used, then temperature measurement precision is improved, but the method becomes unsuitable for regions with significant periodic movements due to loss of phase coherence
Solution Approach 1:
The examination is divided into different regions (first region and second region) based on their motion characteristics. The first region without significant periodic movements uses reference-based thermometry, while the second region with periodic movements uses reference-free thermometry. This segmentation allows each region to be processed with the most suitable method, resolving the contradiction between precision and adaptability.
Solution Approach 2:
Different thermometry methods are applied to different regions according to their specific characteristics. The method selects reference-based approach for stable regions and reference-free approach for moving regions, making the quality of temperature measurement locally optimized rather than applying a uniform method throughout.
2Adaptability or versatility
If reference-free MR thermometry is used, then applicability to moving regions is improved, but temperature measurement precision deteriorates due to spatially limited phase coherence
Solution Approach 1:
The examination is divided into different regions (first region and second region) based on their motion characteristics. The first region without significant periodic movements uses reference-based thermometry, while the second region with periodic movements uses reference-free thermometry. This segmentation allows each region to be processed with the most suitable method, resolving the contradiction between precision and adaptability.
Solution Approach 2:
Different thermometry methods are applied to different regions according to their specific characteristics. The method selects reference-based approach for stable regions and reference-free approach for moving regions, making the quality of temperature measurement locally optimized rather than applying a uniform method throughout.
3Device complexity
If a single thermometry method is applied to all regions, then method simplicity is maintained, but measurement precision deteriorates due to inability to account for regional differences in motion and phase coherence
Solution Approach 1:
The examination is divided into different regions (first region and second region) based on their motion characteristics. The first region without significant periodic movements uses reference-based thermometry, while the second region with periodic movements uses reference-free thermometry. This segmentation allows each region to be processed with the most suitable method, resolving the contradiction between precision and adaptability.
Solution Approach 2:
The method dynamically adapts the thermometry approach based on the characteristics of each region. By determining whether a region has significant periodic movements and assessing phase coherence, the system dynamically selects between reference-based and reference-free methods, optimizing precision without requiring a completely complex unified system.
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 precise temperature determination in regions with and without significant intra-fraction motion by employing different thermometry techniques based on the specific anatomical regions, enhancing the accuracy of temperature measurements.
Implementation Method 1
MR thermometry is based on the physical effect that the proton resonance frequency (PRF) shows a dependency on the temperature. Typically this is a linear dependency. Therefore, a transverse magnetization excited within the scope of MR thermometry shows a corresponding dependency of the acquired phase on the temperature.
Data Source
AI summary
In magnetic resonance (MR) thermometry, first and second magnetic resonance data that are acquired sequentially, from which a phase shift is determined between a measurement phase and a reference phase. In a first region of an examined person, the measurement phase is determined from the second magnetic resonance data and the reference phase is determined from the first magnetic resonance data. In a second region of the examined person, both the reference phase and measurement phase are determined from the second magnetic resonance data. Techniques for reference-based magnetic resonance thermometry and reference-free magnetic resonance thermometry can be applied.