MRI Apparatus Multi-Echo Phase Correction K-Space
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Solution Overview
Problem
Magnetic resonance imaging (MRI) systems using multi-echo sequences face challenges in obtaining high-quality images due to blur and aliasing effects caused by data obtained at different echo times, which are not effectively addressed by existing methods.
Innovation Solution
An MRI apparatus that performs phase correction on echo data obtained at different echo times, using a generalized autocalibrating partially parallel acquisition (GRAPPA) method and additional data from overlapping parts in the k-space to reconstruct high-quality images, thereby reducing echo time shifts, magnetic field inhomogeneity, and spin dephasing effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-echo sequences are used to reduce image acquisition time, then productivity is improved, but image quality deteriorates due to blur and aliasing effects
Solution Approach 1:
The patent segments the k-space data acquisition into multiple echo trains, where each echo train acquires a portion of the k-space data. By dividing the overall acquisition process into multiple segments (echoes) that can be combined, the system achieves faster imaging while maintaining image quality through proper integration of segmented data.
Solution Approach 2:
The patent applies preliminary phase correction to the k-space data from different echo times before combining them. This preliminary action corrects phase errors that would otherwise cause blur and aliasing, ensuring that the data is properly prepared for combination and subsequent image reconstruction.
2Productivity
If data from different echo times are combined without phase correction, then productivity is improved, but measurement precision deteriorates due to phase errors
Solution Approach 1:
The patent implements a feedback mechanism where phase correction is applied based on the actual phase differences observed in the acquired data. The system measures the phase errors from different echo times and applies corrective feedback to align the phases before combining the data, thereby maintaining measurement precision while preserving acquisition efficiency.
3Manufacturing precision
If gradient magnetic field performance is improved to enable gradient echo sequences, then image contrast is improved, but device complexity increases
Solution Approach 1:
The patent utilizes parameter changes in the gradient magnetic field timing and amplitude to generate multiple echoes with different phase encodings. By carefully controlling gradient parameters (timing, strength, direction), the system achieves high image contrast through gradient echo sequences without requiring fundamentally more complex hardware,而是 through optimized parameter manipulation.
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 solution improves the quality of reconstructed images by reducing blur and aliasing, increasing signal-to-noise ratio, and contrast ratio, while also shortening image acquisition time.
Implementation Method 1
Magnetic resonance imaging (MRI) apparatuses for imaging subjects by using magnetic fields
Implementation Method 2
obtaining an MR signal by using a plurality of generated echoes
Implementation Method 3
applying a gradient magnetic field for phase encoding only once during one repetition time (TR)
Data Source
Figure 1~2B
Figure 3A~4A
Figure 4B
AI summary
A magnetic resonance imaging (MRI) apparatus for obtaining a magnetic resonance (MR) image, based on a multi-echo sequence, and a method of the MRI apparatus are provided. The MRI apparatus includes a data obtainer configured to obtain first echo data, based on an echo that is generated at a first echo time, and obtain second echo data, based on an echo that is generated at a second echo time later than the first echo time, the first echo data including a part overlapping a part included in the second echo data in a k-space. The MRI apparatus further includes an image processor configured to reconstruct the MR image, based on the first echo data and the second echo data.