MR Electric Properties Tomography Using Water-Normalized Conductivity Maps
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Solution Overview
Problem
Conventional MR-EPT techniques struggle to accurately differentiate between abnormal/malignant tissue and tissue with high water content, leading to potential misdiagnoses due to the correlation between electric conductivity and water content rather than tissue abnormality.
Innovation Solution
A method involving MR imaging that reconstructs and normalizes electric conductivity maps by subtracting conductivity estimates derived from phase and magnitude MR images, using a rescaling function calibrated with healthy tissue, to identify tissue abnormalities directly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional MR-EPT techniques are used to measure electric conductivity, then the measurement can be obtained from a simple imaging sequence, but regions of high electric conductivity cannot be reliably differentiated from healthy tissue with high water content
Solution Approach 1:
The patent introduces water content mapping as an intermediary measurement to mediate between the raw MR-EPT conductivity data and the final diagnosis. By separately measuring water content and using it to normalize conductivity values, the system can distinguish whether high conductivity is due to pathology or simply high water content, resolving the ambiguity in conventional MR-EPT
Solution Approach 2:
The patent transforms the conductivity measurement from a raw value to a normalized value by changing the parameter space. Instead of using absolute conductivity values, the system uses conductivity normalized by water content, which allows reliable differentiation between abnormal tissue and healthy tissue with high water content while maintaining the simplicity of the imaging sequence
2Reliability
If electric conductivity is used as a biomarker for tissue health, then potential diagnostic information is obtained, but misdiagnoses occur when high conductivity is interpreted as pathology without considering water content
Solution Approach 1:
The patent adds another dimension to the diagnostic information by simultaneously measuring both conductivity and water content. This dimensional expansion allows the system to contextualize conductivity values within the water content framework, preventing misdiagnoses while maintaining diagnostic reliability through a more comprehensive parameter set
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 differentiation between abnormal/malignant tissue and high-water-content tissue by normalizing conductivity maps, reducing misdiagnoses through direct voxel-by-voxel calculation of normalized electric conductivity.
Implementation Method 1
Image-forming MR methods which utilize the interaction between magnetic fields and nuclear spins in order to form two-dimensional or three-dimensional images
Implementation Method 2
The phase map is related to the spatial RF field distribution induced by the RF pulses in the object
Data Source
AI summary
The invention relates to a method of MR imaging of an object (10) placed in an examination volume of an MR system (1). It is an object of the invention to enable an improved differentiation between abnormal/malignant tissue and tissue having a high water content in MR-EPT. The method of the invention comprises the following steps: generating MR signals by subjecting the object (10) to an imaging sequence comprising RF pulses and switched magnetic field gradients; acquiring the MR signals; reconstructing a magnitude MR image and a phase map from the MR signals for a given field of view within the object (10), which phase map is related to the spatial RF field distribution induced by the RF pulses within the field of view; deriving an electric conductivity map from the phase map, which electric conductivity map represents a measurement of the distribution of the electric conductivity within the field of view; deriving a further electric conductivity map from the magnitude MR image, which further electric conductivity map represents an estimation of the electric conductivity resulting from the distribution of water within the field of view; and identifying deviations of the two electric conductivity maps. Moreover, the invention relates to an MR system for carrying out this method as well as to a computer program to be run on an MR system.