MRI Phase Correction via Preliminary Reference Scan
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Solution Overview
Problem
Magnetic resonance imaging (MRI) systems face challenges in obtaining accurate real component images due to spatial phase variations caused by inhomogeneities in the static magnetic field and readout gradient field, especially when using multi-coil configurations, which cannot be corrected by existing methods.
Innovation Solution
The MRI apparatus employs a control unit to execute a first pulse sequence for acquiring data in a 2-dimensional k-space with varying phase encoding, followed by a second sequence for image reconstruction after applying an inversion recovery (IR) pulse, and corrects the phase data using the first sequence's data to reconstruct accurate real component images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase correction is performed using reference phase data obtained by setting phase encode as zero without IR pulses, then T1 contrast accuracy is improved, but spatial phase variation errors from multi-coil inhomogeneity cannot be corrected
Solution Approach 1:
The patent performs a preliminary phase correction scan without IR pulses to obtain reference phase data, then uses this reference data to correct phase errors in the main imaging scan with IR pulses. This preliminary action separates the phase correction step from the main imaging sequence, allowing accurate T1 contrast measurement while correcting spatial phase variations from multi-coil inhomogeneity.
Solution Approach 2:
The patent introduces reference phase data as an intermediary element that mediates between the raw multi-coil signal data and the final corrected image. This reference phase data, obtained from a preliminary scan, serves as a correction map that removes spatial phase variations before the main IR-based T1 weighting is applied, enabling both accuracy and completeness in phase correction.
2Measurement precision
If real component images are reconstructed using only real components to maintain longitudinal magnetization sign, then T1 contrast is improved, but spatial phase variation errors from apparatus and environment remain uncorrected
Solution Approach 1:
The patent performs a preliminary phase correction scan without IR pulses to obtain reference phase data, then uses this reference data to correct phase errors in the main imaging scan with IR pulses. This preliminary action separates the phase correction step from the main imaging sequence, allowing accurate T1 contrast measurement while correcting spatial phase variations from multi-coil inhomogeneity.
Solution Approach 2:
The patent introduces reference phase data as an intermediary element that mediates between the raw multi-coil signal data and the final corrected image. This reference phase data, obtained from a preliminary scan, serves as a correction map that removes spatial phase variations before the main IR-based T1 weighting is applied, enabling both accuracy and completeness in phase correction.
3Adaptability or versatility
If multi-coil configuration is used to improve imaging coverage and signal reception, then imaging capability is enhanced, but spatial phase variation errors are introduced that cannot be corrected by conventional methods
Solution Approach 1:
The patent performs a preliminary phase correction scan without IR pulses to obtain reference phase data, then uses this reference data to correct phase errors in the main imaging scan with IR pulses. This preliminary action separates the phase correction step from the main imaging sequence, allowing accurate T1 contrast measurement while correcting spatial phase variations from multi-coil inhomogeneity.
Solution Approach 2:
The patent introduces reference phase data as an intermediary element that mediates between the raw multi-coil signal data and the final corrected image. This reference phase data, obtained from a preliminary scan, serves as a correction map that removes spatial phase variations before the main IR-based T1 weighting is applied, enabling both accuracy and completeness in phase correction.
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 allows for the precise correction of spatial phase variations, enabling the generation of high-accuracy real component images by accounting for phase errors attributed to the apparatus and environment, even in multi-coil imaging setups.
Implementation Method 1
a static magnetic field generating unit for generating a static magnetic resonance in an imaging space
Implementation Method 2
a gradient magnetic field generating unit for applying a gradient magnetic field pulse to an object placed in the imaging space
Implementation Method 3
a high-frequency irradiation unit for irradiating a high-frequency magnetic field pulse to the object... to excite atomic nuclei such as hydrogen in the living body, and measure nuclear magnetic resonance signals (NMR signals)
Implementation Method 4
a reception unit for obtaining a nuclear magnetic resonance signal produced from the object
Data Source
AI summary
A magnetic resonance imaging system is characterized in that a control unit executes, as pulse sequences, a first sequence for obtaining data of a predetermined 2-dimensional region in a k-space and a second sequence for obtaining data required for reconstruction of an image by irradiating an object to be examined with an inversion recovery pulse and corrects the phase of the data obtained by the second sequence with the data of the 2-dimensional region obtained by the first sequence, and in that a signal processing unit reconstructs a real component image with corrected data.Upon execution of the first sequence, the control unit obtains the data of the predetermined 2-dimensional region in the k-space while varying a phase encoding amount.