MRI Ring Artifact Repair via Spatial Gradient Kernel Search
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Solution Overview
Problem
Magnetic resonance imaging (MRI) techniques face challenges in accurately localizing tissue responses due to paramagnetic materials like joint implants, leading to ring artifacts in three-dimensional multi-spectral imaging, particularly in regions with strong local magnetic induction field gradients.
Innovation Solution
A method involving calculating the spatial gradient of the magnetic induction field, kernel searching to identify affected voxels or pixels, masking the image to isolate these areas, and applying filters to smooth intensities, thereby reducing or eliminating ring artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If 3D multi-spectral MRI techniques are used to reduce bulk susceptibility artifacts, then image quality improves, but ring artifacts appear in regions with strong local magnetic induction field gradients
Solution Approach 1:
The patent segments the image processing into multiple stages: acquiring multi-spectral data to reduce bulk artifacts, then separately identifying and processing ring artifact regions through gradient calculation and kernel searching. This segmentation allows different artifact types to be addressed by specialized techniques without interfering with each other.
Solution Approach 2:
The patent extracts the ring artifact problem from the overall image processing by calculating spatial gradients and using kernel searching to isolate affected regions. By separating the identification and treatment of ring artifacts from the general multi-spectral processing, the solution addresses this specific artifact type without compromising the benefits of 3D MSI techniques.
2Device complexity
If conventional MRI methods are used in the presence of metal implants, then imaging is simpler, but bulk susceptibility artifacts and ring artifacts severely degrade image quality
Solution Approach 1:
The patent performs preliminary actions by acquiring multi-spectral data and calculating magnetic induction field gradients before final image reconstruction. This preliminary processing establishes a foundation for identifying and correcting both bulk susceptibility artifacts and ring artifacts, improving overall image quality despite the increased complexity.
Solution Approach 2:
The patent introduces an intermediary processing stage between data acquisition and final imaging that involves gradient calculation and kernel searching. This intermediary step acts as a bridge that transforms raw multi-spectral data into corrected images by systematically addressing artifact regions before final reconstruction.
3Object-generated harmful factors
If image filtering is applied to reduce ring artifacts, then artifact reduction improves, but image resolution may be compromised
Solution Approach 1:
The patent applies local quality by using kernel searching to identify specific regions affected by ring artifacts and applying filtering only to those localized areas. This approach maintains high resolution in unaffected regions while effectively reducing artifacts in problem areas, achieving artifact reduction without compromising overall image resolution.
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 reduces ring artifacts in MRI images by accurately identifying and correcting distortions near metal implants, enhancing image quality and reducing residual artifacts.
Implementation Method 1
calculating a spatial gradient of a magnetic induction field
Implementation Method 2
applying a filter to smooth intensities of the voxels identified by the image mask
Data Source
AI summary
An apparatus for detecting and repairing a ring artifact in a multi-spectral magnetic resonance image includes an image processor, which is configured to obtain an off-resonance magnetic field map and a deblurred composite image, to calculate a spatial gradient of the image based on the magnetic field map, to kernel search the spatial gradient, to mask the image, based on the kernel search, in order to identify voxels affected by a ring artifact, and to apply a filter in order to smooth intensities of the voxels identified by the image mask.