MRI Conductivity Mapping via Susceptibility Intermediary
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Solution Overview
Problem
Artifacts and noise are generated in susceptibility and conductivity maps used for quantifying electromagnetic properties of tissues due to differences in linearity models.
Innovation Solution
A magnetic resonance imaging apparatus that generates a conductivity map by using a susceptibility map, which is calculated from phase images with different echo times, to reduce noise and improve image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conductivity map is generated using phase value at zero echo time based on linearity model, then quantitative conductivity can be calculated for tumor grading and SAR calculation, but artifacts and noise are generated due to differences in linearity model
Solution Approach 1:
The patent introduces susceptibility map as an intermediary element to mediate between phase images and conductivity map. Instead of directly calculating conductivity from phase values using a linearity model, the method first generates a susceptibility map from multiple phase images with different echo times, then uses this susceptibility map as a mediator to compute the conductivity map. This intermediary approach eliminates artifacts and noise by providing a more stable intermediate representation that captures tissue electromagnetic properties without the limitations of direct linearity assumptions.
Solution Approach 2:
The patent performs preliminary generation of susceptibility map before generating the conductivity map. By first creating the susceptibility map from multiple phase images with different echo times, the method prepares a pre-processed intermediate product that removes artifacts and noise. This preliminary action ensures that when the conductivity map is subsequently generated from the susceptibility map, the harmful artifacts and noise are already eliminated, improving the final measurement precision.
2Measurement precision
If susceptibility map is generated using inclination of phase value to echo time, then quantitative susceptibility can be calculated for diagnosis of bleeding and calcification, but artifacts and noise are generated due to differences in linearity model
Solution Approach 1:
The patent transitions from a single-echo-time phase measurement to multi-echo-time phase measurements, adding the dimension of echo time variation. By acquiring phase images at multiple different echo times and analyzing the inclination of phase values with respect to echo time, the method extracts susceptibility information in a higher-dimensional space. This dimensional expansion allows for more robust susceptibility quantification that is less susceptible to artifacts and noise compared to single-echo-time methods.
3Manufacturing precision
If conductivity map is generated directly from phase images, then conductivity quantification is achieved, but image quality is reduced due to artifacts and noise
Solution Approach 1:
The susceptibility map serves as an intermediary that improves conductivity map quality. Instead of directly generating conductivity map from phase images which introduces artifacts and noise, the method uses susceptibility map as a mediating representation. The susceptibility map captures tissue properties in a way that is less sensitive to artifacts, and when used as input for conductivity calculation, it produces a higher quality conductivity map with reduced artifacts and noise.
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
The solution effectively reduces artifacts and noise in the conductivity map, leading to high-resolution images that accurately quantify electromagnetic properties of tissues.
Implementation Method 1
magnetic resonance imaging apparatus that generates a conductivity map by using a susceptibility map, which is calculated from phase images with different echo times
Data Source
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AI summary
According to one embodiment, the magnetic resonance imaging apparatus has a conductive map generation unit. The conductive map generation unit generates a conductivity map quantitatively indicating the conductivity in the subject using a susceptibility map quantitatively indicating the susceptibility in the subject.