Residual Map for MR Signal Model Consistency
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Solution Overview
Problem
Conventional magnetic resonance imaging methods assume signal model constants to be known, leading to errors in quantitative parameter determination due to deviations from true values, making the fitting process less numerically stable and noisy.
Innovation Solution
A magnetic resonance method and apparatus that generates a residual map from the calculated residual of a quantitative parameter map, allowing for the evaluation of the signal model's quality of fit, enabling iterative modifications to the signal model until an acceptable fit is achieved.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If signal model constants are assumed to be known, then the fitting process is simpler, but errors in quantitative parameter determination occur due to deviations from true values
Solution Approach 1:
The patent calculates a residual map that provides feedback about the quality of fit between the signal model and actual MR data. This residual map is displayed alongside the quantitative parameter map, allowing users to visually assess whether the assumed constants accurately represent the patient's tissue properties, thereby enabling iterative refinement of the signal model without increasing computational complexity
2Measurement precision
If signal model constants are reinterpreted as unknowns, then measurement precision may improve, but the fitting operation becomes less numerically stable and calculated parameters become noisier
Solution Approach 1:
The patent introduces an intermediary visual assessment tool (the residual map) that mediates between the quantitative parameter map and the assumed constants. Instead of directly treating constants as unknowns in the fitting process, the residual map serves as an intermediary that allows visual evaluation of model fit quality, enabling users to determine whether the assumed constants are appropriate for each patient without destabilizing the numerical fitting operation
3Measurement precision
If a residual map is generated and displayed, then the quality of fit can be evaluated and accuracy improved, but the processing time increases
Solution Approach 1:
The patent performs the residual map calculation as a preliminary action that provides immediate visual feedback during the imaging process. By displaying the residual map alongside the quantitative parameter map, the system enables real-time assessment of model fit quality without requiring additional separate processing steps or iterative recalculations, thus minimizing time overhead while improving accuracy
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 residual map serves as an indicator of the signal model's quality, allowing for improved accuracy in quantitative parameter determination by identifying and addressing deviations, thereby enhancing the numerical stability and precision of the fitting process.
Implementation Method 1
a strong, static, homogenous basic magnetic field (also called a B0 field) is generated, having a field strength of 1.5 T Tesla, or more, which causes nuclear spins in the subject to become oriented along the direction of the basic magnetic field
Implementation Method 2
Radio-frequency (RF) excitation pulses are radiated into the examination subject, which trigger the emission of nuclear magnetic resonance signals by the nuclear spins
Implementation Method 3
rapidly activated magnetic gradient fields are superimposed on the basic magnetic field, which spatially code the measurement data. These magnetic field gradients determine the points in the k-space memory at which the measurement data are entered
Data Source
AI summary
In a magnetic resonance (MR) apparatus and method to evaluate the consistency of a signal model used to generate a quantitative parameter map, the residual of the quantitative parameter map is calculated and a residual map is generated. The residual map is displayed together with the quantitative parameter map, with the residual map serving as an indicator of the quality of fit of the signal model.