Magnetic Resonance Imaging Method and Storage Medium

Abstract

This application relates to a magnetic resonance imaging method and a storage medium. The method includes: obtaining a plurality of sampling trajectories of echo signals in the k-space; the plurality of sampling trajectories includes at least two adjacent non-Cartesian sampling trajectories along the phase encoding direction; collecting magnetic resonance signals according to the plurality of sampling trajectories and filling the k-space with the magnetic resonance signals; performing image reconstruction based on the data filled in the k-space to obtain a magnetic resonance image. Using this method can improve the signal acquisition speed and the magnetic resonance imaging speed.

Description

Technical Field

[0001] This application relates to the field of magnetic resonance imaging technology, and in particular to a magnetic resonance imaging method and a storage medium. Background Art

[0002] Magnetic Resonance Imaging (MRI) technology is one of the most advanced medical imaging methods today and has been increasingly widely used in clinical practice and scientific research.

[0003] The biggest problem faced by early MRI equipment and technology was the too slow imaging speed. With the progress of hardware technologies such as the main magnet, gradient system, and radio frequency system, as well as the improvement of various acceleration algorithms, the imaging speed of MRI has been greatly improved. However, how to quickly acquire data remains a problem in the development of current magnetic resonance technology. Summary of the Invention

[0004] Based on this, in view of the above technical problems, it is necessary to provide a magnetic resonance imaging method and a storage medium that can improve the signal acquisition speed and the imaging speed.

[0005] A magnetic resonance imaging method, the method comprising:

[0006] Obtaining a plurality of sampling trajectories of echo signals in the k-space; the plurality of sampling trajectories includes at least two adjacent non-Cartesian sampling trajectories along the phase encoding direction;

[0007] Collecting magnetic resonance signals according to the plurality of sampling trajectories, and filling the k-space with the magnetic resonance signals;

[0008] Performing image reconstruction according to the data filled in the k-space to obtain a magnetic resonance image.

[0009] In one embodiment, obtaining a plurality of sampling trajectories of echo signals in the k-space includes:

[0010] For each sampling trajectory, obtaining at least one of frequency encoding gradient change information, phase encoding gradient change information, and slice selection encoding gradient change information of the sampling trajectory.

[0011] In one embodiment, two adjacent non-Cartesian sampling trajectories along the phase encoding direction are complementary along the frequency readout direction or the phase encoding direction.

[0012] In one embodiment, the above obtaining a plurality of sampling trajectories of echo signals in the k-space includes:

[0013] Obtain the multiple sampling trajectories according to a preset sampling method; wherein, the preset sampling method includes at least one of full sampling, equidistant undersampling, and variable density undersampling.

[0014] In one embodiment, the density of the non-Cartesian sampling trajectories at the center position of the K-space is greater than the density of the non-Cartesian sampling trajectories at the edge position of the K-space.

[0015] A magnetic resonance imaging method, the method comprising:

[0016] Excite a detection object using a scanning sequence to obtain multiple echo signals;

[0017] Fill the multiple echo signals into the K-space to obtain multiple data lines; the multiple data lines include a first non-Cartesian data line and a second non-Cartesian data line that are adjacent and filled along the phase encoding direction;

[0018] Perform image reconstruction according to the multiple data lines filled in the K-space to obtain a magnetic resonance image.

[0019] In one embodiment, the first non-Cartesian data line includes echo signals at multiple phase encoding positions, and the second non-Cartesian data line includes echo signals at multiple phase encoding positions.

[0020] In one embodiment, the first non-Cartesian data line and / or the second non-Cartesian data line oscillate periodically along the frequency encoding direction.

[0021] In one embodiment, the second non-Cartesian data line and the first non-Cartesian data line include echo signals at multiple identical encoding positions.

[0022] A magnetic resonance imaging apparatus, the apparatus comprising:

[0023] A trajectory acquisition module, configured to acquire multiple sampling trajectories of echo signals in the K-space; the multiple sampling trajectories include at least two non-Cartesian sampling trajectories that are adjacent along the phase encoding direction;

[0024] A signal filling module, configured to collect magnetic resonance signals according to the multiple sampling trajectories and fill the magnetic resonance signals into the K-space;

[0025] An image reconstruction module, configured to perform image reconstruction according to the data filled in the K-space to obtain a magnetic resonance image.

[0026] In one embodiment, the above-mentioned trajectory acquisition module is specifically configured to, for each sampling trajectory, acquire at least one of frequency encoding gradient change information, phase encoding gradient change information, and slice selection encoding gradient change information of the sampling trajectory.

[0027] In one embodiment, two adjacent non-Cartesian sampling trajectories along the phase-encoding direction are complementary along the frequency readout direction or the phase-encoding direction.

[0028] In one embodiment, the above-mentioned trajectory acquisition module is specifically configured to acquire a plurality of sampling trajectories according to a preset sampling method; wherein, the preset sampling method includes at least one of full sampling, equidistant undersampling, and variable density undersampling.

[0029] In one embodiment, the density of the non-Cartesian sampling trajectory at the center position of the k-space is greater than the density of the non-Cartesian sampling trajectory at the edge position of the k-space.

[0030] A magnetic resonance imaging device, the device comprising:

[0031] A signal acquisition module, configured to excite a detection object by using a scanning sequence and acquire a plurality of echo signals;

[0032] A signal filling module, configured to fill a plurality of echo signals into the k-space to obtain a plurality of data lines; the plurality of data lines include a first non-Cartesian data line and a second non-Cartesian data line that are adjacent and filled along the phase-encoding direction;

[0033] An image reconstruction module, configured to perform image reconstruction according to the plurality of data lines filled in the k-space to obtain a magnetic resonance image.

[0034] In one embodiment, the first non-Cartesian data line includes echo signals at a plurality of phase-encoding positions, and the second non-Cartesian data line includes echo signals at a plurality of phase-encoding positions.

[0035] In one embodiment, the first non-Cartesian data line and / or the second non-Cartesian data line oscillate periodically along the frequency-encoding direction.

[0036] In one embodiment, the second non-Cartesian data line and the first non-Cartesian data line include echo signals at a plurality of identical encoding positions.

[0037] A computer device, comprising a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0038] Acquire a plurality of sampling trajectories of echo signals in the k-space; the plurality of sampling trajectories include at least two adjacent non-Cartesian sampling trajectories along the phase-encoding direction;

[0039] Collect magnetic resonance signals according to the plurality of sampling trajectories and fill the magnetic resonance signals into the k-space;

[0040] Perform image reconstruction according to the data filled in the k-space to obtain a magnetic resonance image; or,

[0041] Use a scanning sequence to excite the object to be detected and obtain multiple echo signals;

[0042] Fill multiple echo signals into the k-space to obtain multiple data lines; the multiple data lines include a first non-Cartesian data line and a second non-Cartesian data line that are adjacent and filled along the phase encoding direction;

[0043] Perform image reconstruction based on the multiple data lines filled in the k-space to obtain a magnetic resonance image.

[0044] A computer-readable storage medium stores a computer program thereon, and when the computer program is executed by a processor, the following steps are implemented:

[0045] Obtain multiple sampling trajectories of echo signals in the k-space; the multiple sampling trajectories include at least two non-Cartesian sampling trajectories that are adjacent along the phase encoding direction;

[0046] Collect magnetic resonance signals according to the multiple sampling trajectories and fill the magnetic resonance signals into the k-space;

[0047] Perform image reconstruction based on the data filled in the k-space to obtain a magnetic resonance image; or,

[0048] Use a scanning sequence to excite the object to be detected and obtain multiple echo signals;

[0049] Fill multiple echo signals into the k-space to obtain multiple data lines; the multiple data lines include a first non-Cartesian data line and a second non-Cartesian data line that are adjacent and filled along the phase encoding direction;

[0050] Perform image reconstruction based on the multiple data lines filled in the k-space to obtain a magnetic resonance image.

[0051] In the above magnetic resonance imaging method and storage medium, multiple sampling trajectories of echo signals in the k-space are obtained; magnetic resonance signals are collected according to the multiple sampling trajectories and filled into the k-space; image reconstruction is performed based on the data filled in the k-space to obtain a magnetic resonance image. Since the sampling trajectories of the echo signals in the k-space are non-Cartesian trajectories, the number of samplings can be reduced, thereby improving the signal acquisition speed and the magnetic resonance imaging speed. Description of the Drawings

[0052] Figure 1 It is an application environment diagram of the magnetic resonance imaging method in an embodiment;

[0053] Figure 2 It is a schematic flowchart of the magnetic resonance imaging method in an embodiment;

[0054] Figure 3 It is one of the schematic diagrams of multiple sampling trajectories in the k-space in an embodiment;

[0055] Figure 4 One of the schematic diagrams of the sampling trajectory in an embodiment;

[0056] Figure 5 Another one of the schematic diagrams of the sampling trajectory in an embodiment;

[0057] Figure 6 Another one of the schematic diagrams of the sampling trajectory in an embodiment;

[0058] Figure 7 Another one of the schematic diagrams of multiple sampling trajectories in the K-space in an embodiment;

[0059] Figure 8 Another one of the schematic diagrams of multiple sampling trajectories in the K-space in an embodiment;

[0060] Figure 9 Another one of the schematic diagrams of multiple sampling trajectories in the K-space in an embodiment;

[0061] Figure 10 Another one of the schematic diagrams of multiple sampling trajectories in the K-space in an embodiment;

[0062] Figure 11 Another one of the schematic diagrams of multiple sampling trajectories in the K-space in an embodiment;

[0063] Figure 12 The flowchart of the magnetic resonance imaging method in another embodiment;

[0064] Figure 13 The structural block diagram of the magnetic resonance imaging device in an embodiment;

[0065] Figure 14 The structural block diagram of the magnetic resonance imaging device in another embodiment;

[0066] Figure 15 The internal structure diagram of the computer device in an embodiment. Detailed implementation manners

[0067] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0068] The magnetic resonance imaging method provided by the present application can be applied to, for example Figure 1In the application environment shown. The application environment is a magnetic resonance system, and the magnetic resonance system 100 includes a bed 110, an MR scanner 120, and a processor 130. The MR scanner 120 includes a magnet, a radio frequency transmitting coil, a gradient coil, and a radio frequency receiving coil. The bed 110 is used to carry the target object 010. The radio frequency transmitting coil is used to transmit radio frequency pulses to the target object. The gradient coil is used to generate a gradient field, which can be along the phase encoding direction, the slice selection direction, the frequency encoding direction, etc. The radio frequency receiving coil is used to receive magnetic resonance signals. In one embodiment, the magnet of the MR scanner 120 can be a permanent magnet or a superconducting magnet, and according to different functions, the radio frequency coils that make up the radio frequency unit can be divided into a body coil and a local coil. In one embodiment, the types of the radio frequency transmitting coil and the radio frequency receiving coil can be a birdcage coil, a solenoid coil, a saddle coil, a Helmholtz coil, an array coil, a loop coil, etc. In a specific embodiment, the radio frequency transmitting coil is set as a birdcage coil, and the local coil is set as an array coil, and the array coil can be set in a 4-channel mode, an 8-channel mode, or a 16-channel mode.

[0069] The magnetic resonance system 100 further includes a controller 140 and an output device 150. Among them, the controller 140 can simultaneously monitor or control the MR scanner 110, the processor 130, and the output device 150. The controller 140 can include one or a combination of several of a central processing unit (CPU), an application-specific integrated circuit (ASIC), an application-specific instruction set processor (ASIP), a graphics processing unit (GPU), a physics processing unit (PPU), a digital signal processor (DSP), a field-programmable gate array (FPGA), an ARM processor, etc.

[0070] The output device 150, such as a display, can display magnetic resonance images of the region of interest. Further, the output device 150 can also display the height, weight, age, imaging site of the subject, and the working status of the MR scanner 110, etc. The type of the output device 150 can be one or a combination of several of a cathode ray tube (CRT) output device, a liquid crystal output device (LCD), an organic light emitting output device (OLED), a plasma output device, etc.

[0071] The magnetic resonance system 100 can be connected to a local area network (LAN), a wide area network (WAN), a public network, a private network, a proprietary network, a public switched telephone network (PSTN), the Internet, a wireless network, a virtual network, or any combination of the above networks.

[0072] In one embodiment, the processor 130 can control the MR scanner 120 to perform equidistant or non-equidistant sampling on a detection object (a part of the target object 010), and control the MR scanner 120 to acquire the magnetic resonance signal of the detection object, and perform Fourier transform on the magnetic resonance signal to obtain the magnetic resonance image of the detection object.

[0073] In one embodiment, as Figure 2 shown, a magnetic resonance imaging method is provided. Taking the magnetic resonance system in Figure 1 as an example, the method includes the following steps:

[0074] Step 201, obtaining a plurality of sampling trajectories of echo signals in the k-space.

[0075] Before exciting the detection object, the processor of the magnetic resonance system can obtain a plurality of sampling trajectories of echo signals in the k-space set by the user or automatically planned by the system according to the scan sequence, or can obtain a plurality of sampling trajectories of echo signals stored in advance. The embodiments of the present disclosure do not limit this.

[0076] Among them, the plurality of sampling trajectories include two or more adjacent non-Cartesian sampling trajectories in the phase encoding direction. There is at least one intersection point between adjacent non-Cartesian sampling trajectories, or adjacent non-Cartesian sampling trajectories are exactly the same and there is no intersection point. As Figure 3 shown, the data filled in the k-space forms 18 data lines (encoded by echo signals according to the set sampling trajectories), each data line is a non-Cartesian data line (filled with echo signals according to non-Cartesian sampling trajectories), and there is one or more intersection points between every two adjacent sampling data lines. In this embodiment, there are multiple intersection points between two adjacent non-Cartesian data lines along the frequency encoding direction. Another example is Figure 10 shown, the data filled in the k-space forms multiple data lines. Among them, there is no intersection point between two adjacent sampling data lines at the center position of the k-space, and there is an intersection point between two adjacent sampling data lines at the edge position of the k-space.

[0077] Step 202, collecting magnetic resonance signals according to the plurality of sampling trajectories and filling the magnetic resonance signals into the k-space.

[0078] After obtaining the sampling trajectory, the processor of the magnetic resonance system controls the MR scanner to collect magnetic resonance signals according to the obtained sampling trajectory. Then, the processor fills the magnetic resonance signals collected by the MR scanner into the k-space to obtain k-space data / data filled in the k-space. In this embodiment, the k-space is also called the Fourier space, which is the filling space of the original digital data of the magnetic resonance signal with spatial positioning encoding information. Filling the collected magnetic resonance signals into the k-space is to perform spatial positioning encoding (including frequency encoding and phase encoding) on the magnetic resonance signals. It can be understood that once the magnetic resonance signals are filled into the k-space, MR signals with spatial information can be obtained, and the data filled in the k-space is specifically manifested as multiple data lines (phase encoding lines or k-space lines) filled in the k-space.

[0079] It can be understood that since the sampling trajectory is a non-Cartesian sampling trajectory, each non-Cartesian sampling trajectory fills or encodes echo signals corresponding to multiple phase encoding positions. Therefore, a smaller number of sampling trajectories can be set to cover the k-space without affecting the magnetic resonance imaging effect.

[0080] Step 203: Perform image reconstruction based on the data filled in the k-space to obtain a magnetic resonance image.

[0081] After the k-space is filled, image reconstruction processing is performed on the data in the k-space to obtain a magnetic resonance image. Exemplarily, the data reconstruction in the k-space can adopt a sensitivity encoding (SENSE) reconstruction method, a simultaneous acquisition of spatial harmonics (SMASH) method, a generalized autocalibrating partially parallel acquisition (GRAPPA) method, a machine learning-based reconstruction method, a compressed sensing algorithm, etc. The embodiments of the present disclosure do not limit the image reconstruction method, which can be set according to actual situations.

[0082] In the above magnetic resonance imaging method, multiple sampling trajectories of echo signals in the k-space are obtained; magnetic resonance signals are collected according to the multiple sampling trajectories and filled into the k-space; image reconstruction is performed based on the data filled in the k-space to obtain a magnetic resonance image. Since the sampling trajectory of the echo signals in the k-space is a non-Cartesian trajectory, each non-Cartesian sampling trajectory fills or encodes echo signals corresponding to multiple phase encoding positions, so the sampling times can be reduced, thereby improving the signal acquisition speed and the magnetic resonance imaging speed.

[0083] In one embodiment, the factors affecting the sampling trajectory include the parameters of the frequency encoding gradient, the phase encoding gradient, and the slice selection encoding gradient. These parameters may include, for example, the field strength (intensity) of the gradient, when it is applied (application time), and the duration, etc. Exemplarily, the step of obtaining multiple sampling trajectories of the echo signals in the K-space may include: for each sampling trajectory, obtaining the frequency encoding gradient change information, the phase encoding gradient change information, and the slice selection encoding gradient change information of the sampling trajectory.

[0084] The frequency encoding gradient change information includes the correspondence between the frequency encoding gradient strength / gradient amplitude and the time function, as shown in formula (1); the phase encoding gradient change information includes the correspondence between the phase encoding gradient strength and the time function, as shown in formula (2); the slice selection encoding gradient change information includes the correspondence between the slice selection encoding gradient strength and the time function, as shown in formula (3).

[0085] Gx = αf(t) + a ---------------(1)

[0086] Gy = βg(t) + b ---------------(2)

[0087] Gz = γh(t) + c ---------------(3)

[0088] Wherein, Gx is the frequency encoding gradient strength, Gy is the phase encoding gradient strength, and Gz is the slice selection encoding gradient strength; f(t), g(t), and h(t) are all time functions, the value range of the time function is [0, 1], and at least one of the three time functions is a non-linear function; α is the reference value corresponding to the frequency encoding gradient amplitude, β is the reference value corresponding to the phase encoding gradient amplitude, and γ is the reference value corresponding to the slice selection encoding gradient amplitude; a, b, and c are all constants.

[0089] In the case where the K-space is a two-dimensional space, the slice selection encoding gradient ( Figure 4 wherein Gz) strength is 0 or the slice selection encoding gradient is not applied, and the sampling trajectory can form the following curve:

[0090] In the case where the frequency encoding gradient strength is a constant, if the phase encoding gradient strength is a sine wave function, the sampling trajectory correspondingly forms a sine wave curve. As Figure 4 shown, Gx is the constant a, Gy is the sine wave function, and the sampling trajectory forms a curve that oscillates periodically according to the sine wave.

[0091] In the case where the frequency encoding gradient strength is a constant, if the phase encoding gradient strength is a triangular wave function, the sampling trajectory correspondingly forms a curve that oscillates periodically according to the triangular wave.

[0092] When the frequency encoding gradient strength is constant, if the parameters of the phase encoding gradient are set to a plurality of sine waves applied at a first interval along the time direction, the sampling trajectory correspondingly forms a curve in which the sine wave and a first constant are periodically repeated. As Figure 5 shown, Gx is constant, Gy is a plurality of sine waves applied at intervals along the time direction, and the echo signal is filled along the sampling trajectory to form a data line including a plurality of spaced sine waves in the profile. The embodiments of the present disclosure do not limit the first constant.

[0093] When the parameters of the frequency encoding gradient are set to a plurality of sine waves applied at a second interval along the time direction, if the parameters of the frequency encoding gradient are set to a plurality of oscillating waveforms applied at a third interval along the time direction, the sampling trajectory correspondingly forms a curve in which a circle and a straight line are periodically repeated. As Figure 6 shown, Gx is a function in which an oscillating waveform and a constant a are periodically repeated, Gy is a function in which a sine wave and a constant 0 are periodically repeated, and the sampling trajectory forms a curve in which a circle and a straight line are periodically repeated. It can be understood that by changing the oscillating waveform, the oscillating waveform can also form a curve in which an ellipse and a straight line are periodically repeated. The embodiments of the present disclosure do not limit the second constant and the third constant.

[0094] In one embodiment, the step of obtaining a plurality of sampling trajectories of the echo signal in the K space may include: obtaining a plurality of sampling trajectories according to a preset sampling method; wherein, the preset sampling method includes at least one of full sampling, equidistant undersampling, and variable density undersampling.

[0095] In practical applications, if the preset sampling method is full sampling, then a plurality of sampling trajectories as shown in Figure 3 、 Figure 7 can be obtained.

[0096] If the target sampling method is equidistant undersampling, a plurality of sampling trajectories as shown in Figure 8 can be obtained, that is, two adjacent non-Cartesian sampling trajectories along the phase encoding direction are complementary along the frequency readout direction or the phase encoding direction. Figure 8 Compared with Figure 3 , the number of sampling trajectories is reduced. However, since each sampling trajectory is a non-Cartesian sampling trajectory and there is at least one intersection between every two adjacent sampling trajectories, the echo signals can be supplemented with each other between the sampling trajectories, so as to cover the entire K space.

[0097] If the preset sampling method is variable density sampling, a plurality of sampling trajectories as shown in Figure 9 、 Figure 10 、 Figure 11 can be obtained, that is, the density of the non-Cartesian sampling trajectories at the center position of the K space is greater than the density of the non-Cartesian sampling trajectories at the edge position of the K space. Among them,Figure 9 , Figure 10 Compared with Figure 3 , Figure 11 compared with Figure 7 , the sampling density in the middle region of the K-space is high, while that in the two side regions is low. Since the data in the central region of the K-space affects the clarity of the magnetic resonance image, a high sampling density in the central region of the K-space and a low sampling density in the two side regions can not only ensure the clarity of the magnetic resonance image, but also reduce the number of signal acquisitions. In this way, the signal acquisition speed and the magnetic resonance imaging speed can be improved. Additionally, in Figure 9 , the amplitudes of the sampling trajectories in the central region of the K-space are the same, but the starting times are different; while in Figure 10 , both the amplitudes and the starting times of the sampling trajectories in the central region of the K-space are the same. The embodiments of the present disclosure do not specifically limit the shape of the sampling trajectories, which can be set according to actual situations.

[0098] In the above embodiments, for each sampling trajectory, the frequency-encoding gradient change information, the phase-encoding gradient change information, and the slice-selection encoding gradient change information of the sampling trajectory are obtained; different sampling trajectories can be formed according to the frequency-encoding gradient change information, the phase-encoding gradient change information, and the slice-selection encoding gradient change information. However, these sampling trajectories are all non-Cartesian sampling trajectories, and the echo signals can be mutually complemented between adjacent sampling trajectories. Therefore, even a small number of sampling trajectories can cover the entire K-space. Since the number of sampling trajectories is reduced, the signal acquisition speed and the magnetic resonance imaging speed can be improved.

[0099] In one embodiment, as shown in Figure 12 , a magnetic resonance imaging method is provided. Taking the application of this method to the magnetic resonance system in Figure 1 as an example for illustration, the method includes the following steps:

[0100] Step 301: Use a scanning sequence to excite the detection object to obtain a plurality of echo signals.

[0101] The magnetic resonance system includes a spectrometer and a scanner. A main magnet, gradient coils, a radio frequency transmitting coil, and a radio frequency receiving coil are provided in the scanner. During the imaging process, the spectrometer obtains the scanning sequence and controls the gradient coils and the radio frequency transmitting coil to generate gradient pulses and radio frequency pulses respectively according to the scanning sequence to excite the detection object. Among them, the parameters of the scanning sequence include radio frequency pulse parameters, gradient field parameters, and signal acquisition times, etc. By controlling parameters such as radio frequency pulse parameters, gradient field parameters, and signal acquisition times, magnetic resonance signals can be acquired along a preset trajectory.

[0102] After exciting the detection object, the MR scanner of the magnetic resonance system performs signal acquisition and transmits the acquired plurality of echo signals to the processor; the processor obtains the plurality of echo signals transmitted by the MR scanner.

[0103] Step 302: Fill multiple echo signals into the k-space to obtain multiple data lines.

[0104] Among them, the multiple data lines include a first non-Cartesian data line and a second non-Cartesian data line that are adjacent and filled along the phase encoding direction. The first non-Cartesian data line includes echo signals at multiple phase encoding positions, and the second non-Cartesian data line includes echo signals at multiple phase encoding positions. Optionally, the first non-Cartesian data line and / or the second non-Cartesian data line oscillate periodically along the frequency encoding direction. Optionally, the second non-Cartesian data line and the first non-Cartesian data line may include echo signals at multiple identical encoding positions, as Figure 3 shown. Or as Figure 10 shown, the data filled in the k-space forms multiple data lines. Among them, there are no echo signals at the same encoding positions (no intersection points) between two adjacent sampled data lines at the center position of the k-space, and there are multiple echo signals at the same encoding positions (there are intersection points) between two adjacent sampled data lines at the edge position of the k-space.

[0105] After the processor obtains multiple echo signals, the echo signals are filled into the k-space to obtain multiple non-Cartesian data lines. A small number of non-Cartesian data lines can cover the entire k-space, so the number of signal acquisitions can be reduced.

[0106] Step 303: Perform image reconstruction based on the multiple data lines filled in the k-space to obtain a magnetic resonance image.

[0107] After the filling of the k-space is completed, the processor performs image reconstruction based on the multiple data filled in the k-space to obtain a magnetic resonance image. The embodiments of the present disclosure do not limit the image reconstruction method, which can be selected according to the actual situation.

[0108] In one embodiment, it may further include: simultaneously exciting multiple layers of the detected object by using a scan sequence to obtain echo signals corresponding to multiple layers; filling the multiple echo signals into the k-space to obtain multiple data lines; among them, the multiple data lines include a first non-Cartesian data line and a second non-Cartesian data line that are adjacent and filled along the phase encoding direction; performing image reconstruction based on the multiple data lines filled in the k-space to obtain a multi-layer aliased magnetic resonance image; and performing de-aliasing on the multi-layer aliased magnetic resonance image to obtain a magnetic resonance image of each layer.

[0109] It can be understood that simultaneously exciting multiple layers of the detected object can save the excitation time and the magnetic resonance image reconstruction time, thereby improving the magnetic resonance imaging speed.

[0110] In one embodiment, undersampling processing is performed when collecting echo signals:

[0111] Using a scanning sequence to simultaneously excite multiple layers of a detection object, and undersampling to obtain echo signals corresponding to multiple layers; filling the multiple echo signals into the k-space to obtain multiple data lines; wherein, the multiple data lines include a first non-Cartesian data line and a second non-Cartesian data line that are adjacent and filled along the phase encoding direction; performing image reconstruction based on the multiple data lines filled in the k-space to obtain a multi-layer aliased magnetic resonance image; performing de-aliasing on the multi-layer aliased magnetic resonance image to obtain an initial magnetic resonance image for each layer; and performing restoration reconstruction on the initial magnetic resonance image to obtain a target magnetic resonance image for each layer.

[0112] It can be understood that in this embodiment, multi-layer undersampling is first performed, and then the de-aliased image is restored, which can further improve the magnetic resonance imaging speed.

[0113] In the above embodiment, a scanning sequence is used to excite a detection object, multiple echo signals are obtained, the multiple echo signals are filled into the k-space to obtain multiple data lines; and image reconstruction is performed based on the multiple data lines filled in the k-space to obtain a magnetic resonance image. Since the data lines are non-Cartesian data lines, a small number of non-Cartesian data lines can cover the entire k-space, so the number of signal acquisitions can be reduced, and the signal acquisition speed and magnetic resonance imaging speed can be improved.

[0114] It should be understood that although Figures 2 to 12 the steps in the flowchart of Figures 2 to 12 are shown in sequence according to the indication of the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise clearly stated in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover,

[0115] In one embodiment, as Figure 13 shown, a magnetic resonance imaging apparatus is provided, including:

[0116] A trajectory acquisition module 401, configured to acquire multiple sampling trajectories of echo signals in the k-space; the multiple sampling trajectories include at least two non-Cartesian sampling trajectories that are adjacent along the phase encoding direction;

[0117] A signal filling module 402, configured to collect magnetic resonance signals according to the multiple sampling trajectories and fill the magnetic resonance signals into the k-space;

[0118] The image reconstruction module 403 is configured to perform image reconstruction based on the data filled in the k-space to obtain a magnetic resonance image.

[0119] In one embodiment, the above-mentioned trajectory acquisition module 401 is specifically configured to obtain at least one of the frequency-encoding gradient change information, phase-encoding gradient change information, and slice-encoding gradient change information of each sampling trajectory.

[0120] In one embodiment, two adjacent non-Cartesian sampling trajectories along the phase-encoding direction are complementary along the frequency readout direction or the phase-encoding direction.

[0121] In one embodiment, the above-mentioned trajectory acquisition module 401 is specifically configured to obtain a plurality of sampling trajectories according to a preset sampling method; wherein, the preset sampling method includes at least one of full sampling, equidistant undersampling, and variable density undersampling.

[0122] In one embodiment, as Figure 14 shown, a magnetic resonance imaging device is provided, including:

[0123] A signal acquisition module 501, configured to excite a detection object by using a scanning sequence to obtain a plurality of echo signals;

[0124] A signal filling module 502, configured to fill a plurality of echo signals into the k-space to obtain a plurality of data lines; the plurality of data lines include a first non-Cartesian data line and a second non-Cartesian data line that are adjacent and filled along the phase-encoding direction;

[0125] An image reconstruction module 503, configured to perform image reconstruction based on the plurality of data lines filled in the k-space to obtain a magnetic resonance image.

[0126] In one embodiment, the first non-Cartesian data line includes echo signals at a plurality of phase-encoding positions, and the second non-Cartesian data line includes echo signals at a plurality of phase-encoding positions.

[0127] In one embodiment, the first non-Cartesian data line and / or the second non-Cartesian data line oscillate periodically along the frequency-encoding direction.

[0128] In one embodiment, the second non-Cartesian data line and the first non-Cartesian data line include echo signals at a plurality of identical encoding positions.

[0129] For the specific limitations of the magnetic resonance imaging device, reference may be made to the limitations of the magnetic resonance imaging method in the foregoing text, which will not be elaborated herein. Each module in the above magnetic resonance imaging device can be implemented in whole or in part by software, hardware, and their combinations. Each of the above modules can be embedded in the processor of the computer device in hardware form or be independent of it, or can be stored in the memory of the computer device in software form, so as to facilitate the processor to call and execute the operations corresponding to each of the above modules.

[0130] In one embodiment, a computer device is provided. The computer device can be a terminal, and its internal structure diagram can be as Figure 15 shown. The computer device includes a processor, a memory, a communication interface, a display screen, and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner. The wireless manner can be implemented through WIFI, a carrier network, NFC (near field communication), or other technologies. When the computer program is executed by the processor, it implements a magnetic resonance imaging method. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen. The input device of the computer device can be a touch layer covering the display screen, or a button, a trackball, or a touchpad provided on the housing of the computer device, or an external keyboard, touchpad, or mouse, etc.

[0131] Those skilled in the art can understand that Figure 15 the structure shown in

[0132] is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0133] Obtain multiple sampling trajectories of echo signals in the k-space; the multiple sampling trajectories include at least two adjacent non-Cartesian sampling trajectories along the phase encoding direction;

[0134] Collect magnetic resonance signals according to the multiple sampling trajectories and fill the magnetic resonance signals into the k-space;

[0135] Perform image reconstruction based on the data filled in the k-space to obtain a magnetic resonance image.

[0136] In one embodiment, when the processor executes the computer program, the following steps are further implemented:

[0137] For each sampling trajectory, at least one of the frequency-encoding gradient change information, phase-encoding gradient change information, and slice-encoding gradient change information of the sampling trajectory is obtained.

[0138] In one of the embodiments, two adjacent non-Cartesian sampling trajectories along the phase-encoding direction are complementary along the frequency readout direction or the phase-encoding direction.

[0139] In one embodiment, when the processor executes the computer program, the following steps are further implemented:

[0140] Obtain a plurality of sampling trajectories according to a preset sampling method; wherein, the preset sampling method includes at least one of full sampling, equidistant undersampling, and variable density undersampling.

[0141] In one of the embodiments, the density of the non-Cartesian sampling trajectory at the center position of the k-space is greater than the density of the non-Cartesian sampling trajectory at the edge position of the k-space.

[0142] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0143] Obtain a plurality of sampling trajectories of the echo signal in the k-space; the plurality of sampling trajectories include at least two adjacent non-Cartesian sampling trajectories along the phase-encoding direction;

[0144] Collect magnetic resonance signals according to the plurality of sampling trajectories, and fill the magnetic resonance signals into the k-space;

[0145] Perform image reconstruction according to the data filled in the k-space to obtain a magnetic resonance image.

[0146] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented:

[0147] For each sampling trajectory, at least one of the frequency-encoding gradient change information, phase-encoding gradient change information, and slice-encoding gradient change information of the sampling trajectory is obtained.

[0148] In one of the embodiments, two adjacent non-Cartesian sampling trajectories along the phase-encoding direction are complementary along the frequency readout direction or the phase-encoding direction.

[0149] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented:

[0150] Obtain multiple sampling trajectories according to a preset sampling method; wherein, the preset sampling method includes at least one of full sampling, equally-spaced undersampling, and variable-density undersampling.

[0151] In one embodiment, the density of the non-Cartesian sampling trajectory at the center position of the K-space is greater than the density of the non-Cartesian sampling trajectory at the edge position of the K-space.

[0152] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above various methods. Among them, any reference to a memory, storage, database, or other medium used in the various embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical memory, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0153] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0154] The above-described embodiments merely represent several implementation manners of the present application. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A magnetic resonance imaging method, characterized in that, The method includes: Obtaining a plurality of sampling trajectories of echo signals in the k-space; the plurality of sampling trajectories include at least two adjacent non-Cartesian sampling trajectories in the phase encoding direction; two adjacent non-Cartesian sampling trajectories in the phase encoding direction are complementary, and the two adjacent non-Cartesian data lines have a plurality of intersection points in the frequency encoding direction; Collecting magnetic resonance signals according to the plurality of sampling trajectories, and filling the k-space with the magnetic resonance signals; Performing image reconstruction based on the data filled in the k-space to obtain a magnetic resonance image.

2. The method according to claim 1, wherein The obtaining of the plurality of sampling trajectories of echo signals in the k-space includes: For each of the sampling trajectories, obtaining at least one of frequency encoding gradient change information, phase encoding gradient change information, and slice selection encoding gradient change information of the sampling trajectory.

3. The method according to claim 1, characterized in that, The obtaining of the plurality of sampling trajectories of echo signals in the k-space includes: Obtaining the plurality of sampling trajectories according to a preset sampling method; wherein the preset sampling method includes at least one of full sampling, equidistant undersampling, and variable density undersampling.

4. The method according to claim 1, wherein The density of the non-Cartesian sampling trajectory at the center position of the k-space is greater than the density of the non-Cartesian sampling trajectory at the edge position of the k-space.

5. A magnetic resonance imaging method, characterized in that, The method includes: Exciting a detection object by using a scanning sequence to obtain a plurality of echo signals; Filling the plurality of echo signals into the k-space to obtain a plurality of data lines; the plurality of data lines include a first non-Cartesian data line and a second non-Cartesian data line that are adjacent and filled in the phase encoding direction, the first non-Cartesian data line and the second non-Cartesian data line are complementary in the phase encoding direction, and the first non-Cartesian data line and the second non-Cartesian data line have a plurality of intersection points in the frequency encoding direction; Performing image reconstruction based on the plurality of data lines filled in the k-space to obtain a magnetic resonance image.

6. The method according to claim 5, wherein The first non-Cartesian data line includes echo signals at a plurality of phase encoding positions, and the second non-Cartesian data line includes echo signals at a plurality of phase encoding positions.

7. The method according to claim 5, characterized in that The first non-Cartesian data line and / or the second non-Cartesian data line oscillate periodically in the frequency encoding direction.

8. The method according to any one of claims 5 to 7, characterized in that The second non-Cartesian data line and the first non-Cartesian data line include echo signals at a plurality of identical encoding positions.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 8.

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