MRI Phase Error Correction Using Reference Signal Regions
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Solution Overview
Problem
High-speed MRI imaging methods like FSE and EPI face challenges in aligning phases of MR signals due to non-uniform magnetic fields, leading to phase errors that affect image quality.
Innovation Solution
A magnetic resonance imaging apparatus and method that acquires MR signals multiple times following one excitation, with phase correction using reference MR data to calculate and correct phase errors within specific real space regions, improving image data accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-speed imaging methods like FSE or EPI are used to acquire MR signals by one excitation, then imaging speed is improved, but phase alignment of MR signals deteriorates due to non-uniform magnetic fields
Solution Approach 1:
The patent applies preliminary action by acquiring reference MR data before the actual imaging process to characterize the magnetic field non-uniformity. This reference data is used to calculate phase error distributions that are then applied to correct the main imaging data, preventing phase misalignment artifacts in high-speed sequences like FSE and EPI.
Solution Approach 2:
The patent changes parameters by calculating phase error distributions across different regions of the imaging space and applying region-specific correction values. The system divides the imaging area into multiple regions and applies different phase correction parameters to each region, optimizing the balance between imaging speed and phase accuracy.
2Measurement precision
If phase correction is applied to the entire imaging region, then phase error correction is improved, but processing time and computational load increase
Solution Approach 1:
The patent applies segmentation by dividing the imaging region into multiple discrete areas and calculating phase error distributions for each segment separately. This allows the system to focus computational resources on regions with significant phase errors while using simpler corrections or no correction in regions where phase alignment is already adequate, thereby reducing overall processing time.
Solution Approach 2:
The patent implements local quality by applying different phase correction strategies to different regions of the imaging space. Regions with high phase error variability receive detailed multi-region correction, while regions with stable phase characteristics receive minimal or no correction, optimizing the balance between correction accuracy and processing efficiency.
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 corrects phase errors, reducing artifacts and enhancing image quality by determining appropriate phase correction regions based on imaging conditions, such as field of view and object position, thereby improving the accuracy of MR image data.
Implementation Method 1
The MRI apparatus is an imaging diagnostic apparatus which magnetically excites nuclear spins of an object set in a static magnetic field with RF (radio frequency) signals having the Larmor frequency and reconstructs an image based on MR (magnetic resonance) signals generated due to the excitation.
Data Source
AI summary
According to one embodiment, an MRI apparatus includes a data acquiring unit and processing circuitry. The data acquiring unit acquires MR signals for imaging according to data acquiring conditions for acquiring MR signals multiple times following one excitation. The data acquiring unit also acquires reference MR signals for phase correction of real space data for imaging. The real space data are generated based on the MR signals for imaging. The processing circuitry is configured to calculate a phase error, in a real space region, of reference real space data and generate MR image data based on the MR signals for imaging with the phase correction of the real space data for imaging based on the calculated phase error. The reference real space data are generated based on the reference MR signals. The real space region is determined based on conditions of acquiring the reference MR signals or the like.