A method and apparatus for k-space data acquisition and image reconstruction

Abstract

The present application discloses a k-space data acquisition method, an image reconstruction method, and an apparatus. The acquisition method includes: determining a plurality of target acquisition layers of an area of interest; dividing the plurality of target acquisition layers to obtain a plurality of acquisition areas arranged along the in-plane phase encoding direction, each of the acquisition areas including N rows × M columns of sampling points, where N is greater than or equal to 2, M is a positive integer, the arrangement direction of the N rows is the inter-plane phase encoding direction, and the arrangement direction of the M columns is the in-plane phase encoding direction; determining a target acquisition trajectory of echo signals in the k-space at least based on the acquisition order of each of the acquisition areas, so as to acquire k-space data based on the target acquisition trajectory. The method in the present application can achieve parallel acquisition of multiple rows of data, making subsequent image reconstruction clearer and more accurate.

Description

Technical Field

[0001] This application relates to the field of magnetic resonance imaging technology, and particularly to a method for collecting k-space data, an image reconstruction method, and an apparatus therefor. Background Art

[0002] Magnetic Resonance Imaging (MRI) is one of the main imaging modalities in modern medical imaging and has been widely used in medical imaging. Its basic principle is to utilize the magnetic resonance phenomenon, use radiofrequency excitation to excite hydrogen protons in the human body, use a gradient field for position encoding, then use a receiving coil to receive the echo signal with position information, and finally reconstruct the image information through Fourier transform.

[0003] Magnetic Resonance Angiography (MRA) is an important application in MRI practice. MRA is divided into Contrast-enhanced MR Angiography (CE-MRA) and Non-contrast-enhanced MR Angiography (NCE-MRA). However, CE-MRA has problems such as high material and injection costs, and the safety of gadolinium contrast agents; while NCE-MRA does not use contrast agents, is safer, and has low costs. NCE-MRA includes relatively primitive techniques such as Time-of-Flight (TOF) and Phase-Contrast MRA (PC-MRA), and there are also newly developed methods in recent years based on flow encoding, spin labeling, and relaxation.

[0004] Among them, the NCE-MRA method based on the inflow effect utilizes the different responses of spins in stationary tissues and spins in inflowing blood under radiofrequency excitation. Usually, the spins in stationary tissues have experienced multiple radiofrequencies and are in a saturated or partially saturated state, while the inflowing blood arrives with new longitudinal magnetization (Mz = 1), making it appear bright. The traditional Time-of-Flight (TOF) method is also based on this principle. Renal artery angiography generally uses the bSSFP sequence for readout and usually requires respiratory gating to suppress motion artifacts.

[0005] In existing magnetic resonance imaging methods, a 3D bSSFP sequence based on the inflow effect is used. When transmitting the 3D bSSFP sequence, different gradient encodings are performed on the 3D bSSFP sequence to obtain echo signals corresponding to each sampling point in k-space, thereby achieving the acquisition of echo signals, that is, obtaining k-space data. Subsequently, image reconstruction can be performed based on the k-space data. However, when collecting echo signals, since k-space encoding usually adopts linear encoding or center-outward encoding, only the echo signals corresponding to one row of sampling points in k-space can be collected within each respiratory cycle, that is, the second kz row will be collected only after the first kz row is collected. Due to the time difference between the collection times of these two rows of echo signals, with the time interval being the respiratory cycle τ, the echo signals of the two kz rows will have different contrasts, different venous suppression effects, and different fat suppression effects, which will further cause the problem of unclear and inaccurate image reconstruction. Summary of the Invention

[0006] In view of this, the present invention provides a method for collecting k-space data, an image reconstruction method, and a device, mainly aiming to solve the problem that the echo signals of two adjacent kz rows obtained by current acquisition have different contrasts, which further causes the subsequent image reconstruction to be unclear and inaccurate.

[0007] To solve the above problems, the present application provides a method for collecting k-space data, including:

[0008] Determine multiple target acquisition layers of the region of interest;

[0009] Perform regional division on the multiple target acquisition layers to obtain a number of acquisition regions arranged along the phase encoding direction within the layer. Each acquisition region contains N rows × M columns of sampling points, where N is greater than or equal to 2, M is a positive integer, the arrangement direction of the N rows is the interlayer phase encoding direction, and the arrangement direction of the M columns is the intra-layer phase encoding direction;

[0010] Determine the target acquisition trajectory of the echo signal in k-space at least based on the acquisition order of each acquisition region, so as to collect k-space data based on the target acquisition trajectory.

[0011] Optionally, N is greater than or equal to 2 and less than or equal to 6, and M is less than or equal to 4.

[0012] Optionally, before determining the target acquisition trajectory of the echo signal in k-space based on the acquisition order of each acquisition region, the method further includes determining the acquisition order of each acquisition region, specifically including:

[0013] Determine the acquisition region located in the middle position as the starting acquisition region.

[0014] Optionally, the determining of the acquisition order of each of the acquisition regions specifically further includes:

[0015] Taking the starting acquisition region as the center in sequence, and determining the acquisition order of each of the acquisition regions on both sides of the center in a manner of alternating from the center to both sides of the center; or,

[0016] Taking the starting acquisition region as the center in sequence, and determining the acquisition order of each of the acquisition regions on both sides of the center in a manner of collecting one by one from the center to one side of the center and then collecting one by one to the other side of the center.

[0017] Optionally, the determining of the target acquisition trajectory of the echo signals in the k-space based at least on the acquisition order of each of the acquisition regions specifically includes:

[0018] Determining at least the first acquisition trajectory corresponding to each acquisition region based on the trajectory form corresponding to each acquisition region;

[0019] Determining the target acquisition trajectory based on each of the first acquisition trajectories and the acquisition order of each acquisition region;

[0020] Wherein, the trajectory form includes any one of the following: row-by-row form and column-by-column form.

[0021] Optionally, before the determining of the multiple target acquisition layers of the region of interest, the method further includes:

[0022] Applying a first inversion recovery (IR) pulse to the region of interest;

[0023] After the application of the first inversion recovery (IR) pulse ends and after a predetermined time, applying a second inversion recovery (IR) pulse to the region of interest;

[0024] After the application of the second inversion recovery (IR) pulse ends, applying a saturation pulse to the region of interest.

[0025] To solve the above problems, the present application provides an image reconstruction method, including:

[0026] Obtaining k-space data through the above-mentioned k-space data acquisition method;

[0027] Performing image reconstruction based on the k-space data to obtain a target magnetic resonance image.

[0028] To solve the above problems, the present application provides a k-space data acquisition device, including:

[0029] A determination module, configured to determine multiple target acquisition layers of a region of interest;

[0030] A partitioning module, configured to partition regions of the multiple target acquisition layers to obtain a plurality of acquisition regions arranged along the in-layer phase encoding direction. Each of the acquisition regions contains N rows × M columns of sampling points, where N is greater than or equal to 2, M is a positive integer, the arrangement direction of the N rows is the inter-layer phase encoding direction, and the arrangement direction of the M columns is the in-layer phase encoding direction;

[0031] An acquisition module, configured to determine a target acquisition trajectory of echo signals in the k-space at least based on the acquisition order of each of the acquisition regions, so as to acquire k-space data based on the target acquisition trajectory.

[0032] To solve the above problems, the present application provides a storage medium storing a computer program, and when the computer program is executed by a processor, the steps of the k-space data acquisition method described in any one of the above are implemented.

[0033] To solve the above problems, the present application provides an electronic device, which at least includes a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program on the memory, the steps of the k-space data acquisition method described in any one of the above are implemented.

[0034] The present application partitions regions of each acquisition layer to obtain acquisition regions containing at least two rows, which provides a guarantee for subsequently determining a target acquisition trajectory based on each acquisition region and performing parallel acquisition of multi-row data based on the target trajectory, such that the echo signals of two adjacent kz rows no longer have different contrasts, and thus subsequent image reconstruction can be clearer and more accurate.

[0035] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the description. And in order to make the above and other objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention are specifically exemplified below. Description of the Drawings

[0036] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. And throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0037] Figure 1 is a flowchart of a method for acquiring k-space data according to an embodiment of the present application;

[0038] Figure 2 is a schematic diagram of a partition of an acquisition region in an embodiment of the present application;

[0039] Figure 3 Another schematic diagram of the division of the acquisition area in the embodiment of the present application;

[0040] Figure 4 Another schematic diagram of the division of the acquisition area in the embodiment of the present application;

[0041] Figure 5 Schematic diagram of the sequence of each acquisition area in the embodiment of the present application;

[0042] Figure 6 Schematic diagram of the first acquisition trajectory in the embodiment of the present application;

[0043] Figure 7 Another schematic diagram of the first acquisition trajectory in the embodiment of the present application;

[0044] Figure 8 Schematic diagram of the encoding of the target pulse sequence according to the target acquisition trajectory in the embodiment of the present application;

[0045] Figure 9 Schematic diagram of the encoding of the target pulse sequence according to the target acquisition trajectory in the embodiment of the present application;

[0046] Figure 10 Timing diagram of the application of the pulse sequence during the k-space data acquisition in another embodiment of the present application;

[0047] Figure 11 Original renal artery image reconstructed after acquiring k-space data by the acquisition method in the present application;

[0048] Figure 12 Maximum intensity projection (MIP) image of the renal artery reconstructed after acquiring k-space data by the acquisition method in the present application. Detailed implementation manners

[0049] Reference is made herein to the various aspects and features of the present application with reference to the accompanying drawings.

[0050] It should be understood that various modifications can be made to the embodiments claimed herein. Accordingly, the above description should not be construed as limiting, but merely as exemplary of the embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the present application.

[0051] The accompanying drawings, which are included in and constitute a part of this specification, illustrate embodiments of the present application and, together with the general description of the present application given above and the detailed description of the embodiments given below, serve to explain the principles of the present application.

[0052] These and other features of the present application will become apparent from the following description of the preferred forms of the embodiments given as non-limiting examples with reference to the accompanying drawings.

[0053] It should also be understood that although the present application has been described with reference to some specific examples, those skilled in the art can surely implement many other equivalent forms of the present application.

[0054] When combined with the accompanying drawings, the above and other aspects, features, and advantages of the present application will become more apparent in view of the following detailed description.

[0055] Hereinafter, specific embodiments of the present application will be described with reference to the accompanying drawings; however, it should be understood that the claimed embodiments are merely examples of the present application, and it can be implemented in various ways. Well-known and / or repetitive functions and structures are not described in detail to avoid obscuring the present application with unnecessary or redundant details. Therefore, the specific structural and functional details claimed herein are not intended to be limiting, but merely as a basis for the claims and a representative basis for teaching those skilled in the art to use the present application in substantially any suitable detailed structure in a variety of ways.

[0056] This specification may use the phrase "in one embodiment", "in another embodiment", "in yet another embodiment", or "in other embodiments", which may each refer to one or more of the same or different embodiments according to the present application.

[0057] An embodiment of the present application provides a method for k-space data acquisition, as Figure 1 shown, including the following steps:

[0058] Step S101, determining a plurality of target acquisition layers of the region of interest;

[0059] In the specific implementation process of this step, a k-space acquisition model in a three-dimensional Cartesian coordinate system can be specifically established according to the number of encoding lines, that is, the total number of sampling points in k-space. Among them, the number of encoding lines can be obtained in advance based on manual selection or input. After establishing the k-space acquisition model, the acquisition layers corresponding to the y-z plane in the k-space acquisition model can be specifically determined as each target acquisition layer. Among them, the ky direction can be the in-layer phase encoding direction, the kz direction can be the inter-layer phase encoding direction. In some embodiments, the kx direction can also be included, and the kx direction is the frequency encoding direction. kx and ky can be used for in-layer spatial positioning, kz can be used for inter-layer spatial positioning, and in-layer phase encoding, inter-layer phase encoding, and frequency encoding can be realized through gradient coils. The plurality of target acquisition layers form a target acquisition layer group.

[0060] Step S102, dividing the region of the plurality of target acquisition layers to obtain a plurality of acquisition regions arranged along the in-layer phase encoding direction. Each of the acquisition regions contains N rows × M columns of sampling points, where N is greater than or equal to 2, M is a positive integer, the arrangement direction of the N rows is the inter-layer phase encoding direction, and the arrangement direction of the M columns is the in-layer phase encoding direction;

[0061] In this step, when dividing the regions of each target acquisition layer, a uniform division method can be specifically adopted to divide the target acquisition layer into several acquisition regions. For example, when the acquisition layer contains 128 * 128 sampling points, specifically, the number of kz rows = 2 can be determined as the target acquisition layer group (each group of target acquisition groups includes 2 target acquisition layers), and according to the number of ky columns = 2, the target acquisition layer group can be divided into 64 acquisition regions as shown in Figure 2 the figure, that is, each acquisition region contains 2 * 2 sampling points, and the 128 * 128 sampling points are divided into 64 target acquisition layer groups, and each target acquisition layer group is divided into 64 acquisition regions; or it can also be according to the number of ky columns = 2 and the number of kz rows = 4, and the 128 * 128 sampling points can be divided into 32 target acquisition layer groups as shown in Figure 3 the figure, and each target acquisition layer group is divided into 64 acquisition regions, that is, each acquisition region contains 2 * 4 sampling points. For another example, a non-uniform division method can also be used to divide the target acquisition layer into several acquisition regions with different numbers of sampling points. For example, the target acquisition layer can be first divided into several first regions a with different numbers of rows based on the number of rows kz of multiple target acquisition layers, and then each first region can be uniformly divided into several acquisition regions b according to a predetermined number of columns, specifically as shown in Figure 4 the figure. In this step, N can be specifically less than or equal to 6, and M is less than or equal to 4. That is, N is any integer within the interval [2, 6], and M is any integer within the interval [1, 4]. By using the division method in this step to divide and obtain each acquisition region, it can be ensured that each acquisition region contains at least two kz rows, laying a foundation for subsequent multi-line data parallel acquisition, improving the contrast difference between adjacent two kz rows, and improving the image reconstruction effect.

[0062] Step S103: Determine the target acquisition trajectory of the echo signal in the k-space based on at least the acquisition sequence of each of the acquisition regions, so as to acquire k-space data based on the target acquisition trajectory.

[0063] In the specific implementation process of this step, the acquisition order of each acquisition area can be determined in any of the following ways. Method 1: Determine the acquisition area located in the middle position as the starting acquisition area, and then, with the starting acquisition area as the center, collect one by one from the center to one side of the center, and then collect one by one to the other side of the center, so as to determine the acquisition order of each acquisition area on both sides of the center. That is, multiple acquisition areas on one side of the starting acquisition area are multiple first acquisition areas, and multiple acquisition areas on the other side of the starting acquisition area are multiple second acquisition areas. Starting from the starting acquisition area as the acquisition starting point, collect each first acquisition area in the order from near to far from the starting acquisition area, and then collect each second acquisition area in the order from near to far from the starting acquisition area. Method 2: Determine the acquisition area located in the middle position as the starting acquisition area, and determine the acquisition order of each acquisition area on both sides of the center in the way of alternating from the center to both sides of the center; that is, multiple acquisition areas on one side of the starting acquisition area are multiple first acquisition areas, and multiple acquisition areas on the other side of the starting acquisition area are multiple second acquisition areas. As Figure 5 shown, starting from the starting acquisition area as the acquisition starting point, collect in the way of alternating between the first acquisition area and the second acquisition area, and the acquisition directions of multiple first acquisition areas and multiple second acquisition areas are respectively along the direction gradually away from the starting acquisition area. Among them, when determining the starting acquisition area, if there are an even number of acquisition areas along the ky vertical axis / in-layer phase encoding direction, any one of the two acquisition areas located in the middle position can be used as the starting acquisition area. In this step, by using the acquisition area located in the middle position as the starting acquisition area, and then collecting in the direction gradually from the center to both sides of the center with the starting acquisition area as the center, the fat suppression effect can be improved, thereby further providing a guarantee for obtaining accurate and clear target images for subsequent reconstruction.

[0064] In the specific implementation process of this step, after determining the acquisition order of each acquisition area, the following method can be specifically used to determine the target acquisition trajectory: Determine the first acquisition trajectory corresponding to each acquisition area at least based on the trajectory form corresponding to each acquisition area; determine the target acquisition trajectory based on each of the first acquisition trajectories and the acquisition order of each acquisition area. Among them, when determining the first acquisition trajectory corresponding to each acquisition area, specifically, the acquisition starting point in each acquisition area and the trajectory form corresponding to each acquisition area can be determined first, and then the target acquisition trajectory can be determined based on the starting point and the trajectory form, where the trajectory form includes: row-by-row form or column-by-column form. In this embodiment, the route type of the first acquisition trajectory can specifically be: "Z" shape, "U" shape or "N" shape, etc., and can be specifically determined according to the number of sampling points in each acquisition area. For example, as Figure 6 and Figure 7 shown is the route map of the first acquisition trajectory in the row-by-row form.

[0065] In this example, after determining the target acquisition trajectory, the target pulse sequence can be gradient-encoded according to the target acquisition trajectory to acquire k-space data corresponding to the target acquisition trajectory. In the specific implementation process of this embodiment, the target pulse sequence can specifically be a 3D bSSFP sequence. The specific process is as follows: Determine the encoding gradient pairs corresponding to each scanning moment based on the target acquisition trajectory. The encoding gradient pairs include the in-plane phase encoding gradient and the inter-slice phase encoding gradient; successively encode the target pulse sequence based on each encoding gradient pair, and successively apply each encoded target pulse sequence to the region of interest to acquire k-space data corresponding to the target acquisition trajectory. As Figure 8 shown, it is a schematic diagram of encoding the target pulse sequence according to the target acquisition trajectory as Figure 6 shown. As Figure 9 shown, it is a schematic diagram of encoding the target pulse sequence according to the target acquisition trajectory as Figure 7 shown.

[0066] By adopting the method in this application, it is possible to achieve traversing acquisition from the center of the k-space to the two sides of the k-space, with the center being acquired first and the two sides being acquired later, thereby enabling the improvement of the fat suppression effect. During the acquisition process, it is acquired in the way of pairing two points in the same kz row. When traversing from the center to the two sides, it will jump in the positive and negative half-spaces. It always continuously acquires two points in the same row and then jumps to the next row for acquisition. By adopting the hybrid dual-center encoding method in this application, it is acquired in the way of combining the in-plane phase encoding and the inter-slice phase encoding and rearranging them to be from the center to the outside in the phase encoding direction and the slice direction phase encoding. When continuously acquiring multiple rows, the data of multiple rows are acquired in parallel. Taking the example of continuously acquiring two rows of hybrid dual-center encoding outward, its implementation method is as Figure 8 shown.

[0067] Again, for example, traversing acquisition from the center of the k-space to the two sides of the k-space, with the center being acquired first and the two sides being acquired later. Within the same kz row, it is still acquired in the way of pairing two points. In the specific implementation process, it can also be acquired in the way of pairing multiple points. Thereby, it is possible to almost simultaneously acquire the data of two different kz rows. During the acquisition process of the acquisition method in this application, when traversing from the center to the two sides, it will jump in the positive and negative half-spaces, that is, it always continuously acquires four points and then jumps. Its implementation method is as Figure 9 shown.

[0068] Based on the above example, in order to make a further explanation, the following is described in combination with a specific application scenario. A method for acquiring k-space data in this embodiment, for example Figure 10 shown, specifically includes the following steps:

[0069] Step S201: Apply a first inversion recovery (IR) pulse to the region of interest;

[0070] In the specific implementation of this step, respiratory gating can be specifically used. As Figure 10 shown, after the respiratory gating trigger, apply the first IR inversion pulse to both kidneys, with a magnitude sufficient to cover the vascular system of interest, and its function is to suppress the stationary tissues in this region.

[0071] Step S202: After the application of the first inversion recovery (IR) pulse ends and after a predetermined time, apply a second inversion recovery (IR) pulse to the region of interest;

[0072] In the specific implementation of this step, the predetermined time can be set according to the actual situation. Wait for a period of time after the first pulse is applied, and the arterial blood above the tagging band flows into the imaging region to form an inflow enhancement signal. At this time, the second IR pulse can be applied. Specifically, the second inversion pulse can be applied downstream of the kidneys to suppress the signal flowing in from the inferior vena cava.

[0073] Step S203: After the application of the second inversion recovery (IR) pulse ends, apply a saturation pulse to the region of interest;

[0074] In the specific implementation of this step, after applying the second IR pulse, the CHESS saturation pulse can be applied to suppress fat.

[0075] Step S204: Determine multiple target acquisition layers for the region of interest; divide the multiple target acquisition layers to obtain several acquisition regions arranged along the in-plane phase encoding direction. Each of the acquisition regions contains N rows × M columns of sampling points, where N is greater than or equal to 2, M is a positive integer, the arrangement direction of the N rows is the inter-slice phase encoding direction, and the arrangement direction of the M columns is the in-plane phase encoding direction; at least based on the acquisition order of each of the acquisition regions, determine the target acquisition trajectory of the echo signals in the k-space, so as to acquire k-space data based on the target acquisition trajectory.

[0076] In the specific implementation of this step, specifically, based on the target acquisition trajectory, determine the encoding gradient pairs corresponding to each scanning moment. The encoding gradient pairs include the in-plane phase encoding gradient and the inter-slice phase encoding gradient; then sequentially encode the 3D bSSFP sequence based on each of the encoding gradient pairs, and sequentially apply each encoded 3D bSSFP sequence to the region of interest to acquire the k-space data corresponding to the target acquisition trajectory.

[0077] In this embodiment, by determining the target acquisition trajectory and then setting the encoding method to the hybrid dual-center outward encoding method according to the target acquisition trajectory, multiple lines can be acquired at one time, and the respiratory cycle can be filled as much as possible within the available acquisition window, solving the problem that the echo signals of two adjacent kz lines have different contrasts k and different fat suppression effects, which in turn causes the subsequent image reconstruction to be less clear and accurate.

[0078] In this implementation, the 3D bSSFP sequence based on the inflow effect is used as the main body, and the target acquisition trajectory is determined by the method in this application. Then, k-space encoding is performed based on the target acquisition trajectory, thereby realizing data acquisition by hybrid dual-center outward encoding. It realizes continuous acquisition of multiple lines of k-space data within one respiratory cycle, and parallel acquisition of multiple lines of data. And by applying parallel acceleration, the scanning time of each phase-encoding line is reduced, and the saved time can be used to increase the number of continuously acquired lines.

[0079] When performing data acquisition, by paired encoding, that is, continuously acquiring two points in the same line, the artifacts caused by eddy currents can be reduced, making the imaging effect more stable. In this application, when performing multi-line acquisition, since the time intervals of different layer encoding lines from the magnetization preparation module are almost the same, the contrast is guaranteed to be consistent. In addition, since the data in the center of k-space is acquired at a position closer to the fat suppression pulse, the fat suppression effect is improved. By simultaneously acquiring multiple lines, the acquisition efficiency is improved, the scanning speed is accelerated, and thus the scanning time is saved. And the method in this application can adjust the number of continuously scanned lines acquired at one time according to the patient's respiratory cycle, and can make the actual scanning time roughly the same under different respiratory cycles.

[0080] Another embodiment of this application provides an image reconstruction method, including:

[0081] Step 1: Obtain k-space data through the k-space data acquisition method;

[0082] Step 2: Perform image reconstruction based on the k-space data to obtain a target magnetic resonance image.

[0083] In this embodiment, the process of obtaining k-space data in Step 1 can refer to any of the above embodiments of the k-space data acquisition method, and this embodiment will not be repeated here.

[0084] This application divides each acquisition layer into regions to obtain an acquisition region containing at least two lines, which provides a guarantee for subsequently determining the target acquisition trajectory based on each acquisition region and performing parallel acquisition of multiple lines of data based on the target trajectory, so that the echo signals of two adjacent kz lines no longer have different contrasts, and thus the reconstructed image can be clearer and more accurate. For example Figure 11 as shown, is to adopt the method in this applicationFigure 6 After acquiring k-space data by collecting the target acquisition trajectory shown, a raw renal artery image is obtained by performing image reconstruction based on the k-space data; as Figure 12 shown, after acquiring k-space data by collecting the target acquisition trajectory in the present application Figure 6 shown, a maximum intensity projection (MIP) image of the renal artery is obtained by performing image reconstruction based on the k-space data.

[0085] Another embodiment of the present application provides a k-space data acquisition device, including:

[0086] A determination module, configured to determine a plurality of target acquisition layers of an area of interest;

[0087] A division module, configured to perform area division on the plurality of target acquisition layers to obtain a plurality of acquisition areas arranged along the in-plane phase encoding direction. Each of the acquisition areas contains N rows × M columns of sampling points, where N is greater than or equal to 2, M is a positive integer, the arrangement direction of the N rows is the inter-slice phase encoding direction, and the arrangement direction of the M columns is the in-plane phase encoding direction;

[0088] An acquisition module, configured to determine a target acquisition trajectory of echo signals in k-space at least based on the acquisition order of each of the acquisition areas, so as to acquire k-space data based on the target acquisition trajectory.

[0089] In the specific implementation of this example, N is greater than or equal to 2 and less than or equal to 6, and M is less than or equal to 4.

[0090] The k-space data acquisition device in this embodiment further includes an order determination module, and the order determination module is configured to: determine the acquisition area located in the middle position as the starting acquisition area.

[0091] In this embodiment, the order determination module is further configured to: sequentially take the starting acquisition area as the center, and determine the acquisition order of each of the acquisition areas on both sides of the center in a manner of alternating from the center to both sides of the center; or, sequentially take the starting acquisition area as the center, and determine the acquisition order of each of the acquisition areas on both sides of the center in a manner of collecting one by one from the center to one side of the center and then collecting one by one to the other side of the center.

[0092] The acquisition module is specifically configured to: determine a first acquisition trajectory corresponding to each acquisition area at least based on the trajectory form corresponding to each acquisition area; determine the target acquisition trajectory based on each of the first acquisition trajectories and the acquisition order of each acquisition area; where the trajectory form includes any one of the following: row-by-row form and column-by-column form.

[0093] The k-space data acquisition device further includes a preprocessing module for the region of interest, and the preprocessing module is configured to: apply a first inversion recovery (IR) pulse to the region of interest; after the application of the first inversion recovery pulse ends and after a predetermined time, apply a second inversion recovery pulse to the region of interest; and after the application of the second inversion recovery pulse ends, apply a saturation pulse to the region of interest.

[0094] In this application, by dividing each acquisition layer into regions, an acquisition region containing at least two rows is obtained, which provides a guarantee for subsequently determining a target acquisition trajectory based on each acquisition region and performing parallel multi-line data acquisition based on the target trajectory, such that the echo signals of two adjacent kz rows no longer have different contrasts, and thus subsequent image reconstruction can be clearer and more accurate.

[0095] Another embodiment of this application provides a storage medium storing a computer program, and when the computer program is executed by a processor, the following method steps are implemented:

[0096] Step 1, determine multiple target acquisition layers of the region of interest;

[0097] Step 2, divide the multiple target acquisition layers into regions to obtain a plurality of acquisition regions arranged along the in-layer phase encoding direction. Each of the acquisition regions contains N rows × M columns of sampling points, where N is greater than or equal to 2, M is a positive integer, the arrangement direction of the N rows is the inter-layer phase encoding direction, and the arrangement direction of the M columns is the in-layer phase encoding direction;

[0098] Step 3, at least based on the acquisition order of each of the acquisition regions, determine a target acquisition trajectory of echo signals in k-space, so as to acquire k-space data based on the target acquisition trajectory.

[0099] For the specific implementation process of the above method steps, reference can be made to the embodiments of any of the above k-space data acquisition methods, and this embodiment will not be repeated here.

[0100] In this application, by dividing each acquisition layer into regions, an acquisition region containing at least two rows is obtained, which provides a guarantee for subsequently determining a target acquisition trajectory based on each acquisition region and performing parallel multi-line data acquisition based on the target trajectory, such that the echo signals of two adjacent kz rows no longer have different contrasts, and thus subsequent image reconstruction can be clearer and more accurate.

[0101] Another embodiment of this application provides an electronic device including at least a memory and a processor. A computer program is stored on the memory, and when the processor executes the computer program on the memory, the following method steps are implemented:

[0102] Step 1: Determine multiple target acquisition layers of the region of interest;

[0103] Step 2: Divide the multiple target acquisition layers to obtain a number of acquisition regions arranged along the in-plane phase encoding direction. Each acquisition region contains N rows × M columns of sampling points, where N is greater than or equal to 2, M is a positive integer, the arrangement direction of the N rows is the inter-slice phase encoding direction, and the arrangement direction of the M columns is the in-plane phase encoding direction;

[0104] Step 3: Determine the target acquisition trajectory of the echo signal in k-space based at least on the acquisition order of each acquisition region, so as to acquire k-space data based on the target acquisition trajectory.

[0105] For the specific implementation process of the above method steps, reference can be made to the embodiments of any of the above k-space data acquisition methods, and this embodiment will not be repeated here.

[0106] In this application, by dividing each acquisition layer, acquisition regions containing at least two rows are obtained, which provides a guarantee for subsequently determining the target acquisition trajectory based on each acquisition region and performing parallel multi-line data acquisition based on the target trajectory, so that the echo signals of two adjacent kz rows no longer have different contrasts, and thus subsequent image reconstruction can be clearer and more accurate.

[0107] The above embodiments are only exemplary embodiments of this application and are not used to limit this application. The protection scope of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements within the essence and protection scope of this application, and such modifications or equivalent replacements should also be regarded as falling within the protection scope of this application.

Claims

1. A method for k-space data acquisition, characterized in that, Including: Determining a plurality of target acquisition layers of the region of interest, wherein the acquisition layers corresponding to the y-z plane in the k-space acquisition model are determined as each target acquisition layer, the k-space acquisition model is established under a three-dimensional Cartesian coordinate system, the ky direction is the in-plane phase encoding direction, and the kz direction is the inter-plane phase encoding direction; Dividing the plurality of target acquisition layers to obtain a plurality of acquisition regions arranged along the in-plane phase encoding direction, each of the acquisition regions contains N rows × M columns of sampling points, and each of the acquisition regions contains at least two kz rows, where N is greater than or equal to 2 and less than or equal to 6, M is a positive integer and less than or equal to 4, the arrangement direction of the N rows is the inter-plane phase encoding direction, and the arrangement direction of the M columns is the in-plane phase encoding direction; Determining a target acquisition trajectory of the echo signal in the k-space at least based on the acquisition order of each of the acquisition regions and the trajectory form corresponding to each acquisition region, and sequentially acquiring each acquisition region under the target acquisition trajectory to acquire k-space data.

2. The method according to claim 1, wherein Before determining the target acquisition trajectory of the echo signal in the k-space based on the acquisition order of each of the acquisition regions, the method further includes determining the acquisition order of each of the acquisition regions, specifically including: Determining the acquisition region located in the middle position as the starting acquisition region.

3. The method according to claim 2, wherein The determining the acquisition order of each of the acquisition regions specifically further includes: Sequentially taking the starting acquisition region as the center, and determining the acquisition order of each of the acquisition regions on both sides of the center in a manner of alternately moving from the center to both sides of the center; or, Sequentially taking the starting acquisition region as the center, and determining the acquisition order of each of the acquisition regions on both sides of the center in a manner of sequentially acquiring from the center to one side of the center and then sequentially acquiring to the other side of the center.

4. The method according to claim 1, wherein The determining the target acquisition trajectory of the echo signal in the k-space at least based on the acquisition order of each of the acquisition regions specifically includes: Determining a first acquisition trajectory corresponding to each acquisition region at least based on the trajectory form corresponding to each acquisition region; Determining the target acquisition trajectory based on each of the first acquisition trajectories and the acquisition order of each acquisition region; Wherein, the trajectory form includes any one of the following: row-by-row form and column-by-column form.

5. The method according to claim 4, characterized in that, Before determining the plurality of target acquisition layers of the region of interest, the method further includes: Applying a first inversion recovery (IR) pulse to the region of interest; After the application of the first inversion recovery (IR) pulse ends and after a predetermined time, applying a second inversion recovery (IR) pulse to the region of interest; After the application of the second inversion recovery (IR) pulse ends, applying a saturation pulse to the region of interest.

6. An image reconstruction method, characterized in that, Including: Obtaining k-space data by the k-space data acquisition method according to any one of claims 1-5; Performing image reconstruction based on the k-space data to obtain a target magnetic resonance image.

7. A k-space data acquisition device, characterized in that, Including: A determination module, configured to determine a plurality of target acquisition layers of the region of interest, wherein the acquisition layers corresponding to the y-z plane in the k-space acquisition model are determined as each target acquisition layer, the k-space acquisition model is established under a three-dimensional Cartesian coordinate system, the ky direction is the in-plane phase encoding direction, and the kz direction is the inter-plane phase encoding direction; A partitioning module, configured to partition the multiple target acquisition layers to obtain a plurality of acquisition regions arranged along the in-slice phase encoding direction. Each of the acquisition regions contains N rows × M columns of sampling points, and each of the acquisition regions contains at least two kz rows, where N is greater than or equal to 2 and less than or equal to 6, M is a positive integer and less than or equal to 4, the arrangement direction of the N rows is the inter-slice phase encoding direction, and the arrangement direction of the M columns is the in-slice phase encoding direction; An acquisition module, configured to determine a target acquisition trajectory of echo signals in k-space at least based on the acquisition order of each of the acquisition regions and the trajectory form corresponding to each acquisition region, and sequentially acquire each acquisition region along the target acquisition trajectory to acquire k-space data.

8. A storage medium, characterized in that, The storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for acquiring k-space data according to any one of claims 1-5 above are implemented.

9. An electronic device, characterized in that, The electronic device at least includes a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program on the memory, the steps of the method for acquiring k-space data according to any one of claims 1-5 above are implemented.

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