MRI Eddy Current Phase Correction via Differential Thresholding
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Solution Overview
Problem
Current methods for correcting spectral distortion induced by eddy currents in MRI devices are inadequate, as they fail to completely remove low-frequency phase jumps and ringing artifacts, and are complex to process, especially when dealing with multiple phase changes and varying phase change amounts.
Innovation Solution
The method involves identifying and correcting phase jumps in the eddy current correction process using primary time differential values, excluding regions with small phase changes, and interpolating to connect non-phase jump regions, thereby simplifying the correction process and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional eddy current correction methods are used, then spectral distortion correction is performed, but low-frequency phase jumps and ringing artifacts remain and processing complexity increases
Solution Approach 1:
The patent segments the phase value correction process into distinct steps: calculating primary time differential values, identifying phase jump generation regions based on threshold comparisons, excluding these regions, and interpolating to connect non-phase jump regions. This segmentation transforms a complex monolithic correction process into manageable modular steps, reducing processing complexity while maintaining correction accuracy.
Solution Approach 2:
The patent performs preliminary identification and exclusion of phase jump generation regions before performing the main eddy current correction. By calculating primary time differential values and identifying regions where phase jumps occur prior to the correction process, the method prevents these artifacts from contaminating the final correction, thereby improving measurement precision without adding significant processing complexity.
2Productivity
If phase values with phase jumps are used for eddy current correction, then correction is performed, but ringing artifacts are generated and spectrum is degraded
Solution Approach 1:
The patent extracts and removes phase jump generation regions from the phase value data before performing eddy current correction. By identifying regions where the primary time differential value exceeds a threshold and excluding these regions through interpolation, the method removes the source of ringing artifacts while preserving the useful correction information from non-phase jump regions, thereby maintaining spectrum quality.
Solution Approach 2:
The patent introduces primary time differential values as an intermediary metric to identify phase jump generation regions. This intermediary calculation serves as a mediator between the raw phase values and the correction process, enabling selective exclusion of problematic regions while maintaining the integrity of the overall correction, thus improving reliability without sacrificing processing efficiency.
3Measurement precision
If multiple phase changes with varying amounts are corrected using conventional methods, then comprehensive correction is attempted, but processing complexity becomes excessive
Solution Approach 1:
The patent transforms the phase correction problem from directly manipulating phase values to operating on primary time differential values. By changing the parameter domain from phase values to their time derivatives, the method simplifies the identification of phase jump regions through threshold comparisons, making the correction process more systematic and less complex while maintaining or improving correction accuracy for multiple phase changes with varying amounts.
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
This approach effectively suppresses artifacts generated by eddy current correction, enhancing the accuracy of spectral distortion correction and reducing processing complexity, leading to improved quality of magnetic resonance imaging results.
Implementation Method 1
In MRS and MRSI, eddy currents are induced by gradient magnetic fields applied at the time of measurement. Eddy currents cause spatially and temporally uneven static magnetic fields to distort shapes of spectra obtained by the measurement.
Implementation Method 2
radio frequency magnetic field pulse irradiation part for irradiating a radio frequency magnetic field pulse on a subject, and a reception part for receiving magnetic resonance signals generated from the subject
Data Source
AI summary
An object of the present invention is to suppress artifacts generated by correction of spectral distortion induced by eddy currents in MRI devices with a simple method, and thereby improve accuracy of the correction.