A 4d-mri super-resolution reconstruction method based on dual-dictionary learning

Abstract

The invention discloses a 4D-MRI super-resolution reconstruction method based on double-dictionary learning, mainly for solving the problem of quite low special resolution of 4D-MRI reconstructed by use of a conventional method. The main steps comprise: performing retrospective ordering on multi-layer sagittal2D dynamic MRI, leading out 4D-MRI, and cutting a low-resolution image to be improved in a coronal direction; extracting a training image from multi-layer coronal2d dynamic MRI acquired in advance; then training the training image by use of a KSVD algorithm to obtain a high-resolution dictionary and a low-resolution dictionary; and performing super-resolution reconstruction on the low-resolution image to be improved by use of a relation between the high-resolution dictionary and the low-resolution dictionary. The method provided by the invention can effectively improve the special resolution of the 4D-MRI, and can be applied to MRI super-resolution reconstruction in multiple directions.

Description

technical field [0001] The invention belongs to the technical field of image processing, relates to a medical image processing method, and can be used for 4D-MRI super-resolution reconstruction. Background technique [0002] 4D-MRI, also known as three-dimensional dynamic MRI, will provide verifiable information for the current radiation therapy plan. Now, there are two dynamic MRI technologies, one is 3D scanning and the other is 2D multi-slice scanning. The 3D scanning method can provide real time information, but the image quality is not high. 2D multi-slice scanning techniques are better able to accommodate motion during scanning, however more post-processing is required to derive 3D information. [0003] Now, researchers mostly use multi-slice 2D dynamic MRI to generate 4D-MRI. Among them, Siebenthaletal repeatedly collected multiple layers of 2DbSSFP sequence data, and then evaluated the similarity between these sequence data and the navigation layer to sort the imag...

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Problems solved by technology

3D scanning methods can provide real time information, but the image quality is not high

This method is capable of producing high-continuity abdominal MRI stereograms, but has many disadvantages: first, this method requires specific MRI sequences that cannot be used in commercial systems; second, it will be used by It is hampered by a rather complex image processing process; third, how to choose an appropriate liver region to derive a representative average respiratory cycle is still an uncertain issue

[0006] Using the method described above, we were able to obtain a representative 4D-MRI, however, due to the low resolution of the multi-layer 2D dynamic MRI used to derive the 4D-MRI, each layer is about 10mm thick, so we obtained The serial 2D-MRI has low resolution

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