Method for SPEED rapid magnetic resonance imaging based on wavelet domain sparse representation

Abstract

The invention discloses a method for SPEED rapid magnetic resonance imaging based on wavelet domain sparse representation. The method for SPEED rapid magnetic resonance imaging based on wavelet domain sparse representation comprises two steps of regular under-sampled data collection and SPEED image reconstruction based on wavelet domain sparse representation. The regular under-sampled data collection comprises two steps of k-space regular under-sampling and k-space central domain complete sampling. The SPEED image reconstruction based on wavelet domain sparse representation comprises seven steps of zero filling Fourier reconstruction, discrete wavelet transformation, wavelet domain double-layer sparse ghost model construction, overlapped ghost separation based on a least square error method, discrete wavelet reverse transformation, rectification summation of a plurality of ghost images and image reconstruction. The discrete wavelet transformation is used for SPEED data sparse representation, the sparseness of the image is improved through discrete wavelet transformation, and further the quality of the SPEED reconstruction image is improved.

Description

technical field

[0001] The invention belongs to the field of magnetic resonance image imaging, and relates to a SPEED fast magnetic resonance imaging method based on sparse representation of wavelet domain data. Background technique

[0002] Magnetic Resonance Imaging (MRI) is a tomographic imaging technique that uses nuclear magnetic resonance signals measured in vitro to generate physical and chemical properties of organs in vivo. Because MRI has no adverse effects on the body and has the advantages of high soft tissue resolution ability, it has been widely used in clinical disease detection. However, the clinical application of MRI is often limited by the long data acquisition time. For a long time, researchers have improved the MRI data acquisition speed by improving the performance of MRI gradients, developing fast sequences and efficient k-space (frequency space) data acquisition trajectories, reconstruction algorithms and parallel data acquisition, and have achieved ...

Examples

Embodiment Construction

[0050] The present invention will be further described below in conjunction with accompanying drawing.

[0051] The invention mainly includes two major steps: regular under-sampling data collection, and SPEED image reconstruction based on sparse representation of wavelet domain data.

[0052] Regular under-sampling data acquisition includes two steps: regular under-sampling of k-space and full-sampling in the central area of ​​k-space.

[0053] 1-1. Regular undersampling of k-space

[0054] In the phase encoding PE direction of k-space, a row of k-space data is collected every N rows, and a total of three groups are collected (such as figure 1 shown), and three sets of undersampled k-space data are obtained S 1 , S 2 with S 3 (Such as figure 2 shown). use d 1 , d 2 , d 3 Indicates the offset of each group of undersampled data in the PE direction, and the sampling method is N ( d 1 , d 2 , d 3 )express.

[0055] 1-2. Full sampling in the central area ...

technical field

[0001] The invention belongs to the field of magnetic resonance image imaging, and relates to a SPEED fast magnetic resonance imaging method based on sparse representation of wavelet domain data. Background technique

[0002] Magnetic Resonance Imaging (MRI) is a tomographic imaging technique that uses nuclear magnetic resonance signals measured in vitro to generate physical and chemical properties of organs in vivo. Because MRI has no adverse effects on the body and has the advantages of high soft tissue resolution ability, it has been widely used in clinical disease detection. However, the clinical application of MRI is often limited by the long data acquisition time. For a long time, researchers have improved the MRI data acquisition speed by improving the performance of MRI gradients, developing fast sequences and efficient k-space (frequency space) data acquisition trajectories, reconstruction algorithms and parallel data acquisition, and have achieved ...

Examples

Embodiment Construction

[0050] The present invention will be further described below in conjunction with accompanying drawing.

[0051] The invention mainly includes two major steps: regular under-sampling data collection, and SPEED image reconstruction based on sparse representation of wavelet domain data.

[0052] Regular under-sampling data acquisition includes two steps: regular under-sampling of k-space and full-sampling in the central area of ​​k-space.

[0053] 1-1. Regular undersampling of k-space

[0054] In the phase encoding PE direction of k-space, a row of k-space data is collected every N rows, and a total of three groups are collected (such as figure 1 shown), and three sets of undersampled k-space data are obtained S 1 , S 2 with S 3 (Such as figure 2 shown). use d 1 , d 2 , d 3 Indicates the offset of each group of undersampled data in the PE direction, and the sampling method is N ( d 1 , d 2 , d 3 )express.

[0055] 1-2. Full sampling in the central area ...

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