Nonuniformity Correction for Diffusion-Weighted MR Images
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Solution Overview
Problem
Diffusion-weighted magnetic resonance (MR) images often exhibit nonuniformity due to motion artifacts, such as cardiac and breathing movements, leading to shading and inaccurate estimation of diffusion coefficients, which hampers diagnostic accuracy.
Innovation Solution
A method and system for correcting nonuniformity in diffusion-weighted MR images by applying a diffusion-weighted pulse sequence along multiple directions with multiple excitations, deriving a reference and base image, generating a nonuniformity factor image, and combining the images to produce a corrected image that reduces shading and enhances the accuracy of diffusion coefficient estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If diffusion-weighted pulse sequence is applied along multiple directions with multiple excitations, then measurement precision of diffusion coefficients is improved, but device complexity and processing time increase
Solution Approach 1:
A reference image is acquired before the diffusion-weighted imaging sequence to capture the nonuniformity pattern in advance. This preliminary reference image is then used to correct the diffusion-weighted images, eliminating the need for complex post-processing and reducing overall processing complexity while maintaining measurement precision
2Productivity
If motion artifacts from cardiac and breathing movements are present, then imaging speed is maintained, but image quality and uniformity deteriorate
Solution Approach 1:
The patent converts the harmful motion artifacts into useful information by using the reference image acquired during motion to model the nonuniformity pattern. This pattern is then used to correct the diffusion-weighted images, transforming the previously harmful motion effects into a corrective mechanism that improves image uniformity
3Reliability
If nonuniformity correction is applied to diffusion-weighted images, then image quality and diagnostic accuracy are improved, but processing time and computational complexity increase
Solution Approach 1:
The reference image is acquired and processed in advance to establish the nonuniformity correction model. This pre-computed correction map is then applied efficiently to the diffusion-weighted images, reducing the computational burden and processing time compared to performing complex corrections after image acquisition
Data Source
AI summary
A magnetic resonance (MR) imaging method of correcting nonuniformity in diffusion-weighted (DW) MR images of a subject is provided. The method includes applying a DW pulse sequence along a plurality of diffusion directions with one or more numbers of excitations (NEX), and acquiring a plurality of DW MR images of the subject along the plurality of diffusion directions with the one or more NEX. The method also includes deriving a reference image and a base image based on the plurality of DW MR images, generating a nonuniformity factor image based on the reference image and the base image, and combining the plurality of DW MR images into a combined image. The method also includes correcting nonuniformity of the combined image using the nonuniformity factor image, and outputting the corrected image.