MRI Gradient Pulse Correction for Radial Acquisition Trajectory Errors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The radial acquisition method in MRI systems suffers from trajectory errors due to non-ideal gradient pulses, leading to distortion and spatial misregistration in reconstructed images, with existing correction methods being insufficiently accurate.
Innovation Solution
An MRI apparatus and method that utilize prescan-generated correction data to adjust the timing and strength of gradient pulses, allowing for precise correction of trajectory errors in k-space data acquisition, thereby eliminating distortion and misregistration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the radial acquisition method is used to reduce sensitivity to body motion artifacts, then robustness to motion is improved, but trajectory errors occur due to non-ideal gradient pulses causing distortion and spatial misregistration
Solution Approach 1:
The patent applies preliminary action by performing a prescan to measure gradient pulse errors before the actual imaging acquisition. The measured errors are stored and used to correct the gradient pulse application timing and strength during the radial acquisition, thereby preventing trajectory errors from occurring in the final image.
Solution Approach 2:
The patent implements feedback by using the prescan measurements of gradient pulse errors to adjust and correct the gradient pulse application in subsequent imaging acquisitions. The system continuously refines the gradient pulse parameters based on measured deviations, ensuring accurate k-space trajectory following while maintaining motion robustness.
2Measurement precision
If prescan correction data are used to adjust gradient pulse timing and strength, then trajectory error correction accuracy is improved, but imaging time is increased due to additional prescan measurements
Solution Approach 1:
The patent applies partial action by performing gradient calibration measurements on only selected gradient pulse parameters rather than comprehensively characterizing all gradient behavior. This selective measurement approach achieves sufficient correction accuracy for the dominant sources of trajectory error while minimizing the time penalty of the prescan.
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 effectively reduces trajectory errors, resulting in high-quality images with reduced distortion and spatial misregistration, improving the accuracy of image reconstruction in MRI systems.
Implementation Method 1
a static magnetic field magnet (10) configured to generate a static magnetic field
Implementation Method 2
a gradient coil assembly (11) configured to generate gradient magnetic fields
Implementation Method 3
magnetically excites nuclear spin of an object placed in a static magnetic field by applying a radio frequency (RF) pulse having the Larmor frequency
Implementation Method 4
reconstructs an image on the basis of magnetic resonance (MR) signals emitted from the object due to the excitation
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
In one embodiment, an MRI apparatus includes: a scanner including at least two gradient coils; and processing circuitry. The processing circuitry is configured to: cause the scanner to acquire k-space data for correction in a band-shaped two-dimensional k-space along a readout direction, or in a columnar three-dimensional k-space along a readout direction, while changing rotation angles, each of the rotation angles corresponds to the readout direction, generate correction data for correcting an error due to a gradient magnetic field generated by the gradient coils, by using the acquired k-space data for correction, and (A)cause the scanner to acquire k-space data for reconstruction based on a radial acquisition method, while correcting the gradient magnetic field by using the correction data, and generate an image by reconstructing the acquired k-space data for reconstruction, or (B) cause the scanner to acquire k-space data for reconstruction based on the radial acquisition method, correct the k-space for reconstruction data by using the correction data, and generate an image by reconstructing the corrected k-space data for reconstruction.