System and method for magnetic resonance imaging

Patent metadata

Field	Value
Publication number	US-12553970-B2
Application number	US-202418437148-A
Country	US
Kind code	B2
Filing date	Feb 8, 2024
Priority date	Oct 21, 2019
Publication date	Feb 17, 2026
Grant date	Feb 17, 2026

Abstract

A system for MRI is provided. The system may obtain a plurality of sets of under-sampled k-space data corresponding to a plurality of frames. Each set of under-sampled k-space data may be acquired simultaneously from a plurality of slice locations of a subject in one of the frames using an MRI scanner. The system may reconstruct a plurality of reference slice images based on the sets of under-sampled k-space data of the plurality of frames. Each of the reference slice images may be representative of one of the slice locations in more than one frame of the frames. The system may further reconstruct a plurality of image series based on the sets of under-sampled k-space data and the reference slice images. Each image series may correspond to one of the slice locations and include a plurality of slice images of the corresponding slice location in the plurality of frames.

First claim

What is claimed is:

1 . A method for simultaneous multi-slice (SMS) magnetic resonance imaging (MRI), comprising:
acquiring sets of echo signals of a subject corresponding to multiple frames, each of the sets of echo signals corresponding to one of the frames and being acquired by causing an MRI scanner to apply phase-encoding (PE) steps to N slice locations of the subject in the corresponding frame, N being a positive integer greater than 1; reconstructing at least one slice image based on the sets of echo signals, each slice image of the at least one slice image being representative of one slice location of the N slice locations in one frame of the frames, wherein for each of at least one slice location of the N slice locations,
a phase of the slice location is modulated such that a global phase offset of the slice location is equal to (360*k/N) degrees, k being a positive integer, the global phase offset being a phase difference of the slice location between corresponding PE steps that are configured to sample PE lines at a same location in K-space and applied in adjacent frames of the frames.

2 . A method for magnetic resonance imaging (MRI), comprising:
obtaining sets of under-sampled k-space data corresponding to multiple frames, wherein each of the sets of under-sampled k-space data corresponds to one frame of the frames and is acquired simultaneously from multiple slice locations of a subject in the corresponding frame using an MRI scanner, a random undersampling pattern is utilized in each of the frames; reconstructing, based on the sets of under-sampled k-space data of the frames, reference slice images, each of the reference slice images being representative of one of the slice locations in more than one frame of the frames; and reconstructing, based on the sets of under-sampled k-space data and the reference slice images, a plurality of image series each of which corresponds to one of the slice location and includes slice images of the corresponding slice location in the frames.

3 . A system, comprising:
at least one storage device storing a set of instructions for magnetic resonance imaging (MRI); and at least one processor configured to communicate with the at least one storage device, wherein when executing the set of instructions, the at least one processor is configured to direct the system to perform operations including: acquiring sets of echo signals of a subject corresponding to multiple frames, each of the sets of echo signals corresponding to one of the frames and being acquired by causing an MRI scanner to apply phase-encoding (PE) steps to N slice locations of the subject in the corresponding frame, N being a positive integer greater than 1; reconstructing at least one slice image based on the sets of echo signals, each slice image of the at least one slice image being representative of one slice location of the N slice locations in one frame of the frames, wherein for each of at least one slice location of the N slice locations,
a phase of the slice location is modulated such that a global phase offset of the slice location is equal to (360*k/N) degrees, k being a positive integer, the global phase offset being a phase difference of the slice location between corresponding PE steps that are configured to sample PE lines at a same location in K-space and applied in adjacent frames of the frames.

4 . The method of claim 1 , wherein
N is equal to 2, the N slice locations include a first slice location and a second slice location, the phase of the second slice location is modulated such that the global phase offset of the second slice location is equal to 180 degrees.

5 . The method of claim 1 , wherein
N is equal to 3, the N slice locations include a first slice location, a second slice location, and a third slice location, the phase of the second slice location is modulated such that the global phase offset of the second slice location is equal to 120 degrees, and the phase of the third slice location is modulated such that the global phase offset of the third slice location is equal to 240 degrees.

6 . The method of claim 1 , wherein the phase of each of the at least one slice location is modulated by at least one of a phase modulated radio frequency (RF) excitation pulse or a magnetic field gradient.

7 . The method of claim 1 , wherein during each of the PE steps of each of the frames, a compensating magnetic field gradient is applied along the slice-encoding direction after the readout of the corresponding echo signal.

8 . The method of claim 1 , wherein the reconstructing the at least one slice image based on the sets of echo signals comprises:
for each of the frames, reconstructing, based on the corresponding set of echo signals, an aliasing image representative of the N slice locations in the frame; generating, based on the aliasing image of each of the frames, reference slice images, each of the reference slice images being representative of one of the N slice locations in more than one frame of the frames; and reconstructing, based on the aliasing image of each of the frames and the reference slice images, the at least one slice image.

9 . The method of claim 2 , wherein the random undersampling pattern is a pseudo-random sampling pattern.

10 . The method of claim 2 , wherein
the frames include at least one odd frame and the at least one even frame, the slice locations include a first slice location and a second slice location, the phase of at least one of the first slice location or the second slice location is modulated such that:
in each of the at least one odd frame, odd PE lines have a 180° phase difference between the first slice location and the second slice location, and even PE lines have a 0° phase difference between the first slice location and the second slice location,
in each of the at least one even frame, odd PE lines have a 0° phase difference between the first slice location and the second slice location, and even PE lines have a 180° phase difference between the first slice location and the second slice location.

11 . The method of claim 2 , wherein the reconstructing, based on the sets of under-sampled k-space data and the reference slice images, the plurality of image series each of which corresponds to one of the slice locations and includes a plurality of slice images of the corresponding slice location in the comprises:
estimating, based on the reference slice images, a plurality of reconstruction parameters; and reconstructing the plurality of image series by minimizing a value of a cost function, wherein the cost function incorporates at least some of the plurality of reconstruction parameters and the sets of under-sampled k-space data.

12 . The system of claim 3 , wherein
N is equal to 2, the N slice locations include a first slice location and a second slice location, the phase of the second slice location is modulated such that the global phase offset of the second slice location is equal to 180 degrees.

13 . The system of claim 3 , wherein
N is equal to 3, the N slice locations include a first slice location, a second slice location, and a third slice location, the phase of the second slice location is modulated such that the global phase offset of the second slice location is equal to 120 degrees, and the phase of the third slice location is modulated such that the global phase offset of the third slice location is equal to 240 degrees.

14 . The method of claim 4 , wherein
the frames include a first frame and a second frame, the sets of echo signals include a first set of echo signals acquir

Assignees

• Shanghai United Imaging Healthcare Co Ltd

Inventors

• Ding Yu
• Zheng Yuan
• Liu Qi
• Xu Jian

Classifications

• G01R33/5608

  Data processing and visualization specially adapted for MR, e.g. for feature analysis and pattern recognition on the basis of measured MR data, segmentation of measured MR data, edge contour detection on the basis of measured MR data, for enhancing measured MR data in terms of signal-to-noise ratio by means of noise filtering or apodization, for enhancing measured MR data in terms of resolution by means for deblurring, windowing, zero filling, or generation of gray-scaled images, colour-coded images or images displaying vectors instead of pixels (image data processing or generation, in general G06T) · CPC title

• G01R33/5614

  using a fully balanced steady-state free precession [bSSFP] pulse sequence, e.g. trueFISP · CPC title

• G01R33/5611

  Parallel magnetic resonance imaging, e.g. sensitivity encoding [SENSE], simultaneous acquisition of spatial harmonics [SMASH], unaliasing by Fourier encoding of the overlaps using the temporal dimension [UNFOLD], k-t-broad-use linear acquisition speed-up technique [k-t-BLAST], k-t-SENSE (structural details of arrays of sub-coils G01R33/3415) · CPC title

• G01R33/4835 Primary

  of multiple slices · CPC title