Systems and methods for magnetic resonance image reconstruction

1. A system for determining a sampling pattern for magnetic resonance imaging (MRI), comprising:

at least one storage device storing executable instructions, and

at least one processor in communication with the at least one storage device, wherein when executing the executable instructions, the at least one processor causes the system to perform operations including:

determining one or more blocks associated with a plurality of phase encoding (PE) gradient field values, each of the one or more blocks including a plurality of points arranged in a plurality of columns and rows;

determining a plurality of sampling points from each of the one or more blocks, wherein the plurality of sampling points in each of the one or more blocks occupy different points of the corresponding block; and

determining the sampling pattern associated with an image sequence based on the plurality of sampling points in each of the one or more blocks, wherein the sampling pattern is used to acquire encoded MR signals for reconstructing a plurality of images in the image sequence.

2. The system of claim 1 , wherein the each of the one or more blocks includes a plurality of points, and the determining a plurality of sampling points from each of the one or more blocks comprises:

receiving a user instruction; and

selecting, based on the user instruction and from the plurality of points in each of the one or more blocks, the plurality of sampling points.

3. The system of claim 1 , wherein the each of the one or more blocks includes a plurality of points, and the determining a plurality of sampling points from each of the one or more blocks comprises:

selecting, from the plurality of points in each of the one or more blocks, the plurality of sampling points randomly.

4. The system of claim 1 , wherein the one or more blocks includes a first block and a second block of different sizes and/or different counts of sample points.

5. The system of claim 1 , wherein the one or more blocks are of a same size, and the determining the sampling pattern associated with an image sequence based on the plurality of sampling points in each of the one or more blocks comprises:

arranging the one or more blocks along a first dimension and a second dimension to form the sampling pattern, wherein the first dimension is perpendicular to the second dimension.

6. The system of claim 1 , wherein the one or more blocks includes a first count of first blocks of a first size and a second count of second blocks of a second size, and the determining the sampling pattern associated with an image sequence based on the plurality of sampling points in each of the one or more blocks comprises:

arranging the first count of first blocks along a first dimension to form a first segment;

arranging the second count of second blocks along the first dimension to form a second segment; and

combining the first segment and the second segment along a second dimension to form the sampling pattern, wherein the second dimension is perpendicular to the second dimension.

7. The system of claim 6 , wherein the arrangement of the first blocks in the first segment or the arrangement of the second blocks in the second segment is periodic.

8. The system of claim 1 , wherein the at least one processor further causes the system to perform the operations including:

identifying a plurality of sampling trajectories from the sampling pattern, each of the plurality of sampling trajectories corresponding to one of the plurality of images, each of the plurality of sampling trajectories including a plurality of sampling points arranged in a time sequence.

9. The system of claim 8 , wherein a count of the plurality of sampling points on each of the plurality of sampling trajectories is the same.

10. The system of claim 9 , wherein phase encoding gradient field values corresponding to the plurality of sampling points on at least one of the plurality of sampling trajectories vary in a descending order or an ascending order.

11. The system of claim 10 , wherein directions of sampling trajectories with respect to two neighboring images of the image sequence are different, wherein a direction of a sampling trajectory is defined by a change of phase encoding gradient field values corresponding to the plurality of sampling points.

12. The system of claim 11 , wherein the sampling trajectories with respect to the two neighboring images of the image sequence share a sampling point at a phase coding gradient field value, wherein the phase coding gradient field value is a maximum or minimum of the plurality of phase encoding gradient field values associated with the sampling pattern.

13. The system of claim 8 , wherein the at least one processor further causes the system to perform the operations including:

determining a pulse sequence based on the plurality of sampling trajectories;

collecting the encoded MR signals based on the pulse sequence;

determining k-space data associated with the image sequence based on the encoded MR signals; and

reconstructing the image sequence based on the k-space data.

14. The system of claim 13 , wherein the at least one processor further causes the system to perform the operations including:

averaging at least a portion of the k-space data along a time dimension of the sampling pattern to obtain reference k-space data associated with the image sequence; and

reconstructing the image sequence based on the reference k-space data.

15. A method for determining a sampling pattern for magnetic resonance imaging (MRI), implemented on a computing device including at least one processor, at least one storage device, and a communication platform connected to a network, comprising:

determining one or more blocks associated with a plurality of phase encoding (PE) gradient field values, each of the one or more blocks including a plurality of points arranged in a plurality of columns and rows;

determining a plurality of sampling points from each of the one or more blocks, wherein the plurality of sampling points in each of the one or more blocks occupy different points of the corresponding block; and

determining the sampling pattern associated with an image sequence based on the plurality of sampling points in each of the one or more blocks, wherein the sampling pattern is used to acquire encoded MR signals for reconstructing a plurality of images in the image sequence.

16. The method of claim 15 , wherein the one or more blocks includes a first block and a second block of different sizes and/or different counts of sample points.

17. The method of claim 15 , wherein the one or more blocks are of a same size, and the determining the sampling pattern associated with an image sequence based on the plurality of sampling points in each of the one or more blocks comprises:

arranging the one or more blocks along a first dimension and a second dimension to form the sampling pattern, wherein the first dimension is perpendicular to the second dimension.

18. The method of claim 15 , wherein the one or more blocks includes a first count of first blocks of a first size and a second count of second blocks of a second size, and the determining the sampling pattern associated with an image sequence based on the plurality of sampling points in each of the one or more blocks comprises:

arranging the first count of first blocks along a first dimension to form a first segment;

arranging the second count of second blocks along the first dimension to form a second segment; and

combining the first segment and the second segment along a second dimension to form the sampling pattern, wherein the second dimension is perpendicular to the second dimension.

19. The method of claim 15 , further comprising:

identifying a plurality of sampling trajectories from the sampling pattern, each of the plurality of sampling trajectories corresponding to one of the plurality of images, each of the plurality of sampling trajectories including a plurality of sampling points arranged in a time sequence.

20. A non-transitory computer-readable storage medium, comprising at least one set of instructions for determining a sampling pattern for magnetic resonance imaging (MRI), wherein when executed by at least one processor of a computing device, the at least one set of instructions direct the at least one processor to perform acts of:

determining one or more blocks associated with a plurality of phase encoding (PE) gradient field values, each of the one or more blocks including a plurality of points arranged in a plurality of columns and rows;

determining a plurality of sampling points from each of the one or more blocks, wherein the plurality of sampling points in each of the one or more blocks occupy different points of the corresponding block; and

determining the sampling pattern associated with an image sequence based on the plurality of sampling points in each of the one or more blocks, wherein the sampling pattern is used to acquire encoded MR signals for reconstructing a plurality of images in the image sequence.