Magnetic Resonance Image Distortion Correction via Lookup Table
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Solution Overview
Problem
In magnetic resonance imaging, isocenter scanning methods require distortion-corrected images for accurate spatial coordination, but storing both distorted and corrected images increases data volume, leading to longer examination times and reduced patient throughput, as undistorted images are needed for precise measurement planning, which is not efficiently handled by current systems.
Innovation Solution
A method to transform distortion-corrected magnetic resonance images back into equivalent measured images using field inhomogeneity values, allowing for quick retrieval of original image characteristics without the need to store both types of images, thereby reducing computational burden and examination time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If distortion-corrected images are stored for accurate spatial coordination, then measurement precision is improved, but data storage volume increases
Solution Approach 1:
The patent creates a simplified copy of the distortion correction information by pre-calculating and storing only the displacement vectors in a lookup table, rather than storing complete corrected images. This allows rapid retrieval of spatial coordination data with minimal storage requirements.
Solution Approach 2:
The patent extracts only the essential distortion correction data (displacement vectors) from the full distortion correction process and stores separately, while the original measured images can be stored without full distortion correction. This separation reduces the storage burden while maintaining measurement precision when needed.
2Reliability
If both distorted and distortion-corrected images are stored, then reliability of measurement planning is improved, but examination time increases
Solution Approach 1:
The patent performs distortion correction calculations in advance and stores the results in a lookup table during system calibration or initialization. This preliminary action eliminates the need to perform time-consuming distortion corrections during actual measurement planning, thereby maintaining reliability while reducing examination time.
Solution Approach 2:
The patent applies partial distortion correction by storing only the necessary displacement information rather than complete corrected images. This partial action provides sufficient reliability for measurement planning without the full computational burden of complete distortion correction.
3Manufacturing precision
If distortion correction is performed for all images, then manufacturing precision of images is improved, but computational burden increases
Solution Approach 1:
The patent segments the distortion correction process into two parts: (1) pre-computation of displacement vectors stored in a lookup table, and (2) simple vector application during image processing. This segmentation reduces computational burden during actual use while maintaining manufacturing precision through the pre-computed accurate displacement data.
Solution Approach 2:
The patent changes the representation of distortion correction from full image transformation to simplified displacement vector parameters stored in a lookup table. This parameter change maintains the essential distortion correction accuracy while dramatically reducing computational complexity and memory requirements.
Data Source
AI summary
A method for carrying out magnetic resonance measurements on an examination object in a magnetic resonance system is described. In at least one embodiment, a magnetic resonance image of the examination object previously acquired via the magnetic resonance system is used to determine spatial coordinates in order to control the magnetic resonance system for the magnetic resonance measurement to be carried out. In this case, in order to determine the spatial coordinates, use is made of a distortion-corrected magnetic resonance image generated on the basis of an original magnetic resonance measured image acquired by the magnetic resonance system and transformed in advance into an equivalent measured image on the basis of field inhomogeneity values of the magnetic resonance system.