Magnetic resonance imaging method, magnetic resonance imaging device, magnetic resonance imaging equipment, medium and magnetic resonance imaging system

Abstract

The invention relates to a magnetic resonance imaging method, device and equipment, a medium and a magnetic resonance imaging system. The method comprises the following steps: applying a first excitation pulse signal to a scanning part of a target object by adopting magnetic resonance imaging equipment, and applying a dispersion gradient pair to the scanning part on each coding axis; the dispersion gradient centering comprises a reverse dispersion gradient; applying a first refocusing pulse signal to the scanning part to obtain a first pulse signal; and encoding the first pulse signal to generate a first magnetic resonance signal, and performing magnetic resonance imaging according to the first magnetic resonance signal to obtain a magnetic resonance image of the target object. The dispersion gradient pair is placed between the first excitation pulse signal and the first refocusing pulse signal, and cross terms generated by the dispersion gradient pair and other gradients can be eliminated, so that the calculation process of the dispersion gradient amplitude can be simplified, the calculation precision of the dispersion gradient amplitude can be improved, and the image quality of the magnetic resonance image can be improved.

Description

Technical Field

[0001] The present application relates to the field of medical technology, and in particular to a magnetic resonance imaging method, apparatus, device, medium and magnetic resonance imaging system. Background Art

[0002] With the development of medical technology, magnetic resonance technology includes diffusion-weighted imaging technology, which is used to obtain diffusion-weighted images through the random thermal motion of water molecules. Diffusion-weighted images are of great significance for the analysis and research of tissue structure.

[0003] However, the current diffusion-weighted imaging method has the problem of poor image quality of diffusion-weighted images. Summary of the Invention

[0004] Based on this, it is necessary to provide a magnetic resonance imaging method, apparatus, device, medium and magnetic resonance imaging system that can improve the image quality of diffusion-weighted images in order to address the above technical problems.

[0005] In a first aspect, the present application provides a magnetic resonance imaging method, comprising:

[0006] Applying a first excitation pulse signal to a scanning portion of a target object using a magnetic resonance imaging device, and applying a diffusion gradient pair to the scanning portion on each encoding axis; the diffusion gradient pair includes a reverse diffusion gradient;

[0007] applying the first focusing pulse signal to the scanning part to obtain a first pulse signal;

[0008] The first pulse signal is coded to generate a first magnetic resonance signal, and magnetic resonance imaging is performed based on the first magnetic resonance signal to obtain a magnetic resonance image of the target object.

[0009] In one embodiment, applying a diffusion gradient pair to the scanning region on each encoding axis includes:

[0010] Applying a first gradient on each encoding axis for the scanning site, and applying a second gradient on each encoding axis for the scanning site after a preset interval;

[0011] The second gradient and the first gradient have the same amplitude, opposite directions, and the same duration; and the preset interval time is the first time value.

[0012] In one embodiment, the encoding axes include a first phase encoding axis, a second phase encoding axis, and a frequency encoding axis, and applying a first gradient on each encoding axis with respect to the scanning region, and applying a second gradient on each encoding axis with respect to the scanning region after a preset interval, comprises:

[0013] Applying a first diffusion gradient to the scanning region on the first phase encoding axis, and applying a second diffusion gradient after a first preset interval time;

[0014] Applying a third diffusion gradient to the scanning region on the second phase encoding axis, and applying a fourth diffusion gradient after a second preset interval;

[0015] applying a fifth diffusion gradient to the scanning region on the frequency encoding axis, and applying a sixth diffusion gradient after a third preset interval time;

[0016] The durations of the first diffusion gradient, the second diffusion gradient, the third diffusion gradient, the fourth diffusion gradient, the fifth diffusion gradient, and the sixth diffusion gradient are the same; and the first preset interval time, the second preset interval time, and the third preset interval time are the same.

[0017] In one embodiment, the method further comprises:

[0018] Applying a second excitation pulse signal to the scanning site, and applying the diffusion gradient pair to the scanning site on each of the encoding axes; the second excitation pulse signal has the same amplitude and direction as the first excitation pulse signal;

[0019] applying the second refocusing pulse signal to the scanning part to obtain a second pulse signal; the second refocusing pulse signal and the first refocusing pulse signal have a phase angle difference of 180 degrees;

[0020] performing encoding processing on the second pulse signal to generate a second magnetic resonance signal;

[0021] The performing magnetic resonance imaging according to the first magnetic resonance signal to obtain a magnetic resonance image of the target object includes:

[0022] Magnetic resonance imaging is performed according to the first magnetic resonance signal and the second magnetic resonance signal to obtain a magnetic resonance image of the target object.

[0023] In one embodiment, performing magnetic resonance imaging based on the first magnetic resonance signal and the second magnetic resonance signal to obtain a magnetic resonance image of the target object includes:

[0024] performing averaging processing on the first magnetic resonance signal and the second magnetic resonance signal to obtain an average signal;

[0025] The average signal is processed to obtain a magnetic resonance image of the target object.

[0026] In one embodiment, the encoding axis includes a first phase encoding axis, a second phase encoding axis, and a frequency encoding axis, and encoding the first pulse signal to generate the first magnetic resonance signal includes:

[0027] Applying a phase encoding gradient on the first phase encoding axis and the second phase encoding axis to the scanning position to obtain a first intermediate signal;

[0028] Applying a readout gradient on the frequency encoding axis to the scanning position to obtain a second intermediate signal;

[0029] The first magnetic resonance signal is generated based on the first intermediate signal and the second intermediate signal.

[0030] In a second aspect, the present application further provides a magnetic resonance imaging device, comprising:

[0031] a first applying module, configured to apply a first excitation pulse signal to a scanning portion of a target object using a magnetic resonance imaging device, and apply a diffusion gradient pair to the scanning portion on each encoding axis; the diffusion gradient pair includes a reverse diffusion gradient;

[0032] a second applying module, configured to apply the first focusing pulse signal to the scanning part to obtain a first pulse signal;

[0033] The imaging module is configured to perform encoding processing on the first pulse signal to generate a first magnetic resonance signal, and perform magnetic resonance imaging based on the first magnetic resonance signal to obtain a magnetic resonance image of the target object.

[0034] In a third aspect, the present application further provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the magnetic resonance imaging method in the first aspect when executing the computer program.

[0035] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the magnetic resonance imaging method in the first aspect.

[0036] In a fifth aspect, the present application also provides a magnetic resonance imaging system, which includes a magnetic resonance imaging device and a computer device, wherein the magnetic resonance imaging device is connected to the computer device, and the computer device is used to execute the steps of the magnetic resonance imaging method in the first aspect above.

[0037] The above-mentioned magnetic resonance imaging method, apparatus, device, medium, and magnetic resonance imaging system use a magnetic resonance imaging device to apply a first excitation pulse signal to a scanning portion of a target object, and apply a diffusion gradient pair to the scanning portion on each encoding axis; the diffusion gradient pair includes an opposite diffusion gradient; a first refocusing pulse signal is applied to the scanning portion to obtain a first pulse signal; the first pulse signal is encoded to generate a first magnetic resonance signal, and magnetic resonance imaging is performed based on the first magnetic resonance signal to obtain a magnetic resonance image of the target object. The embodiment of the present application eliminates the cross terms generated by the diffusion gradient pair and other gradients by placing the diffusion gradient pair between the first excitation pulse signal and the first refocusing pulse signal, thereby simplifying the calculation process of the diffusion gradient amplitude, improving the calculation accuracy of the diffusion gradient amplitude, and further improving the image quality of the final magnetic resonance image. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments of the present application or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 A diagram of an application environment of a magnetic resonance imaging method according to an embodiment;

[0040] Figure 2 is a schematic flow chart of a magnetic resonance imaging method according to an embodiment;

[0041] Figure 3 is a schematic flow chart of a magnetic resonance imaging method according to another embodiment;

[0042] Figure 4 Schematic diagram of a two-excitation process in one embodiment;

[0043] Figure 5 is a schematic flow chart of a magnetic resonance imaging method in an optional embodiment;

[0044] Figure 6 is a schematic structural diagram of a magnetic resonance imaging system in one embodiment;

[0045] Figure 7FIG. 4 is a structural block diagram of a magnetic resonance imaging device in one embodiment. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0048] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0049] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0050] With the advancement of medical technology, magnetic resonance imaging (MRI) can be used to strengthen the magnetic field outside the object being measured, causing the protons in the object to generate a macroscopic magnetization vector. Radiofrequency excitation pulses are then transmitted to the object, causing the macroscopic magnetization vector to precess around the direction of the magnetic field, thereby generating a magnetic resonance signal. This signal is then processed to produce a magnetic resonance image. Magnetic resonance imaging techniques include diffusion-weighted imaging (DWI), which uses the random thermal motion of water molecules to generate diffusion-weighted images. Diffusion-weighted images are of great significance for the analysis and study of tissue structure.

[0051] However, current diffusion-weighted imaging methods place diffusion gradients on either side of a focusing pulse. Furthermore, when a focusing pulse is applied, a slice selection gradient is simultaneously applied. Consequently, the focusing pulse is often accompanied by a slice selection gradient. This pulse sequence configuration, on the one hand, results in cross-terms between the diffusion gradient and the slice selection gradient, making it difficult to calculate the diffusion gradient amplitude, reducing its accuracy and, consequently, affecting the quality of the resulting diffusion-weighted image. On the other hand, it also results in prolonged echo times and a reduced signal-to-noise ratio, resulting in poor quality of the resulting diffusion-weighted image. Consequently, current diffusion-weighted imaging methods suffer from poor image quality.

[0052] After introducing the background technology of the magnetic resonance imaging method provided by the embodiment of the present application, the following briefly describes the implementation environment involved in the magnetic resonance imaging method provided by the embodiment of the present application. The magnetic resonance imaging method provided by the embodiment of the present application can be applied to Figure 1 The computer device shown in the figure can be a terminal or a server. The computer device includes a processor, memory, an input / output interface, a communication interface, a display unit, and an input device. The processor, memory, and input / output interface are connected via a system bus, while the communication interface, display unit, and input device are connected to the system bus via the input / output interface. The processor of the computer device provides computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operating system and computer program stored in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals via wired or wireless means. The wireless means can be implemented via Wi-Fi, a mobile cellular network, NFC (near field communication), or other technologies. When executed by the processor, the computer program implements a magnetic resonance imaging method. The display unit of the computer device is used to produce a visual image and can be a display screen, a projection device, or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device casing, or an external keyboard, touchpad or mouse.

[0053] Those skilled in the art will understand that Figure 1 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific terminal may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0054] In one embodiment, Figure 2 As shown, a magnetic resonance imaging method is provided, which is applied to Figure 1 The computer device in the example is used to illustrate the process, including the following steps:

[0055] S201 , applying a first excitation pulse signal to a scanning portion of a target object using a magnetic resonance imaging device, and applying a diffusion gradient pair to the scanning portion on each encoding axis; the diffusion gradient pair includes a reverse diffusion gradient.

[0056] The target object refers to a subject undergoing magnetic resonance imaging. For example, the target object may be a patient undergoing diffusion-weighted imaging, and the scanned area may be the head, legs, abdomen, or other parts of the target object. The first excitation pulse signal is used to excite the magnetization vector of the hydrogen atoms. The encoding axis may include at least one phase encoding axis and / or a frequency encoding axis. A diffusion gradient pair includes two diffusion gradients in opposite directions.

[0057] In an embodiment of the present application, a computer device may use a magnetic resonance imaging device to apply a first excitation pulse signal to a scanning part of a target object on a radio frequency axis, and after applying the first excitation pulse signal, apply a diffusion gradient pair to the scanning part on each encoding axis. The radio frequency axis is used to illustrate the time and correspondence of each radio frequency signal in a sequence. Optionally, after applying the first excitation pulse signal, a diffusion gradient pair may be applied to the scanning part on each encoding axis immediately; or, after applying the first excitation pulse signal, a diffusion gradient pair may be applied to the scanning part on each encoding axis after a period of time. Of course, the embodiment of the present application does not limit the specific implementation method of applying the diffusion gradient pair. It should be noted that, in the embodiment of the present application, the diffusion gradient pair is applied only after applying the first excitation pulse signal.

[0058] S202 , applying a first focusing pulse signal to the scanned area to obtain a first pulse signal.

[0059] In an embodiment of the present application, the computer device may apply a first refocusing pulse signal to the scanning part on the radio frequency axis after applying a diffusion gradient pair to the scanning part on each encoding axis to obtain a first pulse signal. Optionally, the first refocusing pulse signal may be applied to the scanning part on the radio frequency axis immediately after the diffusion gradient pair is applied; or, the first refocusing pulse signal may be applied to the scanning part on the radio frequency axis after a period of time after the diffusion gradient pair is applied. Of course, the embodiment of the present application does not limit the specific implementation method of applying the first refocusing pulse signal. It should be noted that the embodiment of the present application applies the first refocusing pulse signal only after the diffusion gradient pair is applied, that is, the embodiment of the present application places the diffusion gradient pair between the first excitation pulse signal and the first refocusing pulse signal.

[0060] S203 , encoding the first pulse signal to generate a first magnetic resonance signal, and performing magnetic resonance imaging according to the first magnetic resonance signal to obtain a magnetic resonance image of the target object.

[0061] In an embodiment of the present application, the computer device can encode the first pulse signal on each encoding axis and sample it using a plane echo method to obtain a first magnetic resonance signal. Thus, optionally, the computer device can directly perform magnetic resonance imaging based on the first magnetic resonance signal to obtain a magnetic resonance image of the target object; or, the computer device can also pre-acquire a second magnetic resonance signal, and then perform magnetic resonance imaging based on the first magnetic resonance signal and the second magnetic resonance signal to obtain a magnetic resonance image of the target object. Of course, the embodiment of the present application does not limit the specific implementation method of magnetic resonance imaging. Among them, the magnetic resonance image can be a magnetic resonance diffusion-weighted image.

[0062] In the above-mentioned magnetic resonance imaging method, a magnetic resonance imaging device is used to apply a first excitation pulse signal to a scanning portion of a target object, and a diffusion gradient pair is applied to the scanning portion on each encoding axis; the diffusion gradient pair includes an opposite diffusion gradient; a first refocusing pulse signal is applied to the scanning portion to obtain a first pulse signal; the first pulse signal is encoded to generate a first magnetic resonance signal, and magnetic resonance imaging is performed based on the first magnetic resonance signal to obtain a magnetic resonance image of the target object. By placing the diffusion gradient pair between the first excitation pulse signal and the first refocusing pulse signal, the embodiment of the present application can eliminate cross terms generated by the diffusion gradient pair and other gradients, thereby simplifying the calculation process of the diffusion gradient amplitude, improving the calculation accuracy of the diffusion gradient amplitude, and further improving the image quality of the resulting magnetic resonance image.

[0063] In one embodiment, a method for applying a diffusion gradient pair is provided, namely, the step of "applying a diffusion gradient pair on each encoding axis for the scanning region" in S201, including:

[0064] A first gradient is applied on each encoding axis for a scanning region, and after a preset interval, a second gradient is applied on each encoding axis for the scanning region.

[0065] The diffusion gradient pair includes a first gradient and a second gradient, wherein the second gradient has the same amplitude and opposite direction as the first gradient, and the second gradient has the same duration as the first gradient. The preset interval time is a first time value, which can be any number equal to or not equal to 0.

[0066] In the embodiment of the present application, optionally, if the preset interval time is 0, the computer device may apply a first gradient to the scanning portion on each encoding axis, and immediately apply a second gradient to the scanning portion on each encoding axis after applying the first gradient; or, if the preset interval time is not 0, the computer device may apply the first gradient to the scanning portion on each encoding axis, and apply the second gradient to the scanning portion on each encoding axis after the preset interval time. Of course, the embodiment of the present application does not limit the specific implementation method of applying the first gradient and the second gradient.

[0067] In one embodiment, if the encoding axes include a first phase encoding axis, a second phase encoding axis, and a frequency encoding axis, then the step of "applying a first gradient on each encoding axis to the scanning region, and applying a second gradient on each encoding axis to the scanning region after a preset interval" includes:

[0068] Applying a first diffusion gradient to a scanning region on a first phase encoding axis, and applying a second diffusion gradient after a first preset interval time;

[0069] Applying a third diffusion gradient to the scanning site on the second phase encoding axis, and applying a fourth diffusion gradient after a second preset interval time;

[0070] A fifth diffusion gradient is applied to the scanning region on the frequency encoding axis, and a sixth diffusion gradient is applied after a third preset interval time.

[0071] The encoding axes include a first phase encoding axis, a second phase encoding axis, and a frequency encoding axis. The durations t of the first diffusion gradient, the second diffusion gradient, the third diffusion gradient, the fourth diffusion gradient, the fifth diffusion gradient, and the sixth diffusion gradient are all the same. The first preset interval, the second preset interval, and the third preset interval are all the same. The first preset interval, the second preset interval, and the third preset interval can all be zero, or can be non-zero.

[0072] In an embodiment of the present application, optionally, if the first preset interval time, the second preset interval time, and the third preset interval time are all 0, the computer device can apply a first diffusion gradient on the first phase encoding axis to the scanning part, and apply a second diffusion gradient on the first phase encoding axis immediately after applying the first diffusion gradient; while applying the first diffusion gradient, a third diffusion gradient can be applied on the second phase encoding axis to the scanning part, and a fourth diffusion gradient can be applied on the second phase encoding axis immediately after applying the third diffusion gradient; while applying the first diffusion gradient, a fifth diffusion gradient can also be applied on the frequency encoding axis to the scanning part, and a sixth diffusion gradient can be applied on the frequency encoding axis immediately after applying the fifth diffusion gradient.

[0073] Alternatively, if the first preset interval time, the second preset interval time, and the third preset interval time are all not 0, the computer device may apply a first diffusion gradient on the first phase encoding axis to the scanning part, and apply a second diffusion gradient on the first phase encoding axis after the first preset interval time; while applying the first diffusion gradient, a third diffusion gradient may be applied on the second phase encoding axis to the scanning part, and a fourth diffusion gradient may be applied on the second phase encoding axis after the second preset interval time; while applying the first diffusion gradient, a fifth diffusion gradient may be applied on the frequency encoding axis to the scanning part, and a sixth diffusion gradient may be applied on the frequency encoding axis after the third preset interval time.

[0074] For example, assuming that the first diffusion gradient and the second diffusion gradient have a diffusion gradient amplitude of G1, the third diffusion gradient and the fourth diffusion gradient have a diffusion gradient amplitude of G2, the fifth diffusion gradient and the sixth diffusion gradient have a diffusion gradient amplitude of G3, and the diffusion sensitivity factor is known to be b, the diffusion gradient table is , the gyromagnetic ratio is , then the calculation method of the diffusion gradient amplitude is as follows:

[0075] , ,

[0076] In this embodiment, a first gradient can be applied to the scanning part on each encoding axis, and after a preset interval time, a second gradient can be applied to the scanning part on each encoding axis. In this way, a first gradient and a second gradient with the same amplitude, opposite direction, and the same duration can be applied between the first excitation pulse signal and the first refocusing pulse signal.

[0077] In one embodiment, Figure 3 As shown, a method for implementing magnetic resonance imaging is also provided, that is, the above-mentioned magnetic resonance imaging method further includes:

[0078] S204 , applying a second excitation pulse signal to the scanned portion, and applying a diffusion gradient pair to the scanned portion on each encoding axis; the second excitation pulse signal has the same amplitude and direction as the first excitation pulse signal.

[0079] In an embodiment of the present application, a computer device may use a magnetic resonance imaging device to apply a second excitation pulse signal to a scanning part of a target object on a radio frequency axis, and after applying the second excitation pulse signal, apply a diffusion gradient pair to the scanning part on each encoding axis. Optionally, a diffusion gradient pair may be applied to the scanning part on each encoding axis immediately after applying the second excitation pulse signal; or, a diffusion gradient pair may be applied to the scanning part on each encoding axis after a period of time after applying the second excitation pulse signal. Of course, the embodiment of the present application does not limit the specific implementation method of applying the diffusion gradient pair. It should be noted that, in the embodiment of the present application, the diffusion gradient pair is applied only after applying the second excitation pulse signal. The second excitation pulse signal has the same amplitude and direction as the first excitation pulse signal.

[0080] S205 , applying a second focusing pulse signal to the scanned portion to obtain a second pulse signal; the second focusing pulse signal and the first focusing pulse signal have a phase angle difference of 180 degrees.

[0081] In an embodiment of the present application, the computer device may apply a second refocusing pulse signal to the scanning part on the radio frequency axis after applying a diffusion gradient pair to the scanning part on each encoding axis to obtain a second pulse signal. Optionally, the second refocusing pulse signal may be applied to the scanning part on the radio frequency axis immediately after applying the diffusion gradient pair; or, the second refocusing pulse signal may be applied to the scanning part on the radio frequency axis after a period of time after applying the diffusion gradient pair. Of course, the embodiment of the present application does not limit the specific implementation method of applying the second refocusing pulse signal. It should be noted that the embodiment of the present application applies the second refocusing pulse signal only after applying the diffusion gradient pair, that is, the embodiment of the present application places the diffusion gradient pair between the second excitation pulse signal and the second refocusing pulse signal. The phase angle of the second refocusing pulse signal differs by 180 degrees from that of the first refocusing pulse signal.

[0082] S206: Encode the second pulse signal to generate a second magnetic resonance signal.

[0083] In an embodiment of the present application, the computer device can encode the second pulse signal on each encoding axis and perform sampling using a plane echo method to obtain a second magnetic resonance signal.

[0084] That is, it can be understood that the embodiment of the present application can set up two consecutive excitation processes, and the encoding method and the application method of the diffusion gradient in the two consecutive excitation processes are completely consistent. Figure 4 As shown, Figure 4 Schematic diagram of two excitation processes in one embodiment. In the first excitation process (i.e., S201-S203), the phase angle of the first excitation pulse signal is 0°, the phase angle of the first focusing pulse signal is 90°, and the first magnetic resonance signal is In the second excitation process (ie, S204-S206), the phase angle of the second excitation pulse signal is 0°, the phase angle of the second focusing pulse signal is 270°, and the second magnetic resonance signal is .

[0085] The step of “performing magnetic resonance imaging according to the first magnetic resonance signal to obtain a magnetic resonance image of the target object” in S203 includes:

[0086] S207 , performing magnetic resonance imaging according to the first magnetic resonance signal and the second magnetic resonance signal to obtain a magnetic resonance image of the target object.

[0087] In an embodiment of the present application, the computer device may first perform signal processing on the first magnetic resonance signal and the second magnetic resonance signal to obtain processed signals, and then perform magnetic resonance imaging based on the processed signals to obtain a magnetic resonance image of the target object.

[0088] In one embodiment, S207 includes:

[0089] An average processing is performed on the first magnetic resonance signal and the second magnetic resonance signal to obtain an average signal.

[0090] The average signal is processed to obtain a magnetic resonance image of the target object.

[0091] In the embodiment of the present application, the computer device can process the first magnetic resonance signal and the second magnetic resonance signal Take the complex average and get the average signal S, that is, S= Thus, the computer device can perform Fourier transform processing on the average signal to obtain an artifact-free three-dimensional magnetic resonance image of the target object.

[0092] In this embodiment, two consecutive excitation processes can be performed on the same k-space, and the phase angles of the excitation pulses in the two consecutive excitation processes are consistent, and the phase angles of the refocusing pulses differ by 180°, that is, a phase cycle is added between the two excitations, and the first magnetic resonance signal and the second magnetic resonance signal can be respectively acquired through the two excitation processes. Therefore, magnetic resonance imaging is performed after averaging the two acquired magnetic resonance signals, so that the phases introduced by the stray field cancel each other out, which helps to eliminate artifacts in the magnetic resonance image and can improve the image quality of the magnetic resonance image.

[0093] In one embodiment, the encoding axis includes a first phase encoding axis, a second phase encoding axis, and a frequency encoding axis. Based on this, a method for implementing encoding processing is provided, namely, the "encoding the first pulse signal to generate the first magnetic resonance signal" in S203, including:

[0094] Phase encoding gradients are applied to the scanning region on the first phase encoding axis and the second phase encoding axis to obtain a first intermediate signal.

[0095] A readout gradient is applied to the scanning region on the frequency encoding axis to obtain a second intermediate signal.

[0096] A first magnetic resonance signal is generated based on the first intermediate signal and the second intermediate signal.

[0097] In the embodiment of the present application, since the encoding axes include a first phase encoding axis, a second phase encoding axis, and a frequency encoding axis, after applying the first focusing pulse signal, the computer device can apply phase encoding gradients on the first phase encoding axis and the second phase encoding axis to the scanning region to perform phase encoding processing on the first excitation pulse signal to obtain a first intermediate signal. Optionally, the phase encoding gradients applied on the first phase encoding axis and the second phase encoding axis to the scanning region can be the same, or they can be different. For example, the phase encoding method can include but is not limited to K-space encoding methods. At the same time, the computer device can also apply a readout gradient on the frequency encoding axis to the scanning region to perform frequency encoding processing on the first excitation pulse signal to obtain a second intermediate signal. Thus, the computer device can sample the first intermediate signal and the second intermediate signal using a planar echo method to obtain a first magnetic resonance signal. In addition, the method for generating the second magnetic resonance signal is similar to the method for generating the first magnetic resonance signal and is not described in detail here.

[0098] In this embodiment, a phase encoding gradient and a readout gradient can be applied to the phase encoding axis and the frequency encoding axis, respectively, thereby performing phase encoding and frequency encoding processing on the first excitation pulse signal, thereby accurately obtaining a first intermediate signal and a second intermediate signal. Furthermore, by sampling both the accurate first intermediate signal and the accurate second intermediate signal, a first magnetic resonance signal can be accurately generated.

[0099] In an optional embodiment, if Figure 5 As shown, a magnetic resonance imaging method is provided, which is applied to a computer device, comprising:

[0100] S301, applying a first excitation pulse signal to a scanning part of a target object using a magnetic resonance imaging device;

[0101] S302, applying a first diffusion gradient to a scanning region on a first phase encoding axis, and applying a second diffusion gradient after a first preset interval time;

[0102] S303, applying a third diffusion gradient to the scanning part on the second phase encoding axis, and applying a fourth diffusion gradient after a second preset interval time;

[0103] S304, applying a fifth diffusion gradient to the scanning site on the frequency encoding axis, and applying a sixth diffusion gradient after a third preset interval time;

[0104] S305, applying a first focusing pulse signal to the scanned area to obtain a first pulse signal;

[0105] S306, applying a phase encoding gradient on the first phase encoding axis and the second phase encoding axis to the scanning position to obtain a first intermediate signal;

[0106] S307, applying a readout gradient to the scanning portion on the frequency encoding axis to obtain a second intermediate signal;

[0107] S308, generating a first magnetic resonance signal according to the first intermediate signal and the second intermediate signal;

[0108] S309, applying a second excitation pulse signal to the scanned portion, and applying a diffusion gradient pair to the scanned portion on each encoding axis; the second excitation pulse signal has the same amplitude and direction as the first excitation pulse signal;

[0109] S310, applying a second focusing pulse signal to the scanned portion to obtain a second pulse signal; the second focusing pulse signal and the first focusing pulse signal have a phase angle difference of 180 degrees;

[0110] S311, encoding the second pulse signal to generate a second magnetic resonance signal;

[0111] S312 , performing averaging processing on the first magnetic resonance signal and the second magnetic resonance signal to obtain an average signal; and processing the average signal to obtain a magnetic resonance image of the target object.

[0112] In the above-mentioned magnetic resonance imaging method, a magnetic resonance imaging device is used to apply a first excitation pulse signal to a scanning portion of a target object, and a diffusion gradient pair is applied to the scanning portion on each encoding axis; the diffusion gradient pair includes an opposite diffusion gradient; a first refocusing pulse signal is applied to the scanning portion to obtain a first pulse signal; the first pulse signal is encoded to generate a first magnetic resonance signal, and magnetic resonance imaging is performed based on the first magnetic resonance signal to obtain a magnetic resonance image of the target object. By placing the diffusion gradient pair between the first excitation pulse signal and the first refocusing pulse signal, the embodiment of the present application can eliminate cross terms generated by the diffusion gradient pair and other gradients, thereby simplifying the calculation process of the diffusion gradient amplitude, improving the calculation accuracy of the diffusion gradient amplitude, and further improving the image quality of the resulting magnetic resonance image.

[0113] In addition, it should be noted that the embodiment of the present application adopts a pulsed global excitation method, which eliminates the need to apply a layer selection gradient while applying the excitation pulse and the refocusing pulse. The time for applying the layer selection gradient during the excitation pulse and the refocusing pulse is omitted, which helps to shorten the echo time and reduce signal attenuation, thereby improving the signal-to-noise ratio of the magnetic resonance image.

[0114] It should be understood that, although the steps in the flowcharts of the above embodiments are shown in sequence as indicated by the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be performed in other orders. Moreover, at least a portion of the steps in the flowcharts of the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily performed at the same time, but can be performed at different times. The execution order of these steps or stages is not necessarily to be performed in sequence, but can be performed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0115] In one embodiment, Figure 6 As shown, a magnetic resonance imaging system is provided, including the magnetic resonance imaging device 21 and the computer device 22. The magnetic resonance imaging device 21 is connected to the computer device 22, and the computer device 22 is used to execute the steps of the magnetic resonance imaging method in any of the above embodiments.

[0116] The magnetic resonance imaging device 21 may include but is not limited to a main magnet system, a gradient system, and a radio frequency system. The main magnet system is used to generate a stable and uniform static magnetic field. The main magnet system may include at least a superconducting magnet, a permanent magnet, etc. The gradient system may include at least a gradient coil and a drive circuit, etc. The radio frequency system is composed of a radio frequency transmitter and a receiving coil. The specific structural diagram of the computer device 22 can be referred to. Figure 1As shown, no further details are given here.

[0117] Based on the same inventive concept, embodiments of the present application further provide a magnetic resonance imaging apparatus for implementing the aforementioned magnetic resonance imaging method. The solution provided by this apparatus is similar to the solution described in the aforementioned method. Therefore, the specific limitations of one or more magnetic resonance imaging apparatus embodiments provided below can be found in the above-described limitations of the magnetic resonance imaging method and will not be further elaborated here.

[0118] In an exemplary embodiment, Figure 7 As shown, a magnetic resonance imaging device is provided, comprising: a first applying module 31, a second applying module 32 and an imaging module 33, wherein:

[0119] The first applying module 31 is used to apply a first excitation pulse signal to a scanning part of the target object using a magnetic resonance imaging device, and apply a diffusion gradient pair to the scanning part on each encoding axis; the diffusion gradient pair includes a reverse diffusion gradient.

[0120] The second applying module 32 is used to apply a first focusing pulse signal to the scanning part to obtain a first pulse signal.

[0121] The imaging module 33 is configured to perform encoding processing on the first pulse signal to generate a first magnetic resonance signal, and perform magnetic resonance imaging according to the first magnetic resonance signal to obtain a magnetic resonance image of the target object.

[0122] In one embodiment, the first application module 31 includes:

[0123] A first applying unit is configured to apply a first gradient on each encoding axis to the scanning portion, and apply a second gradient on each encoding axis to the scanning portion after a preset interval;

[0124] The second gradient and the first gradient have the same amplitude, opposite directions, and the same duration; and the preset interval time is the first time value.

[0125] In one embodiment, the encoding axis includes a first phase encoding axis, a second phase encoding axis, and a frequency encoding axis, and the first applying unit includes:

[0126] a first applying subunit, configured to apply a first diffusion gradient to a scanning region on a first phase encoding axis, and to apply a second diffusion gradient after a first preset interval;

[0127] a second applying subunit, configured to apply a third diffusion gradient to the scanning site on the second phase encoding axis, and to apply a fourth diffusion gradient after a second preset interval;

[0128] a third applying subunit, configured to apply a fifth diffusion gradient to the scanning site on the frequency encoding axis, and apply a sixth diffusion gradient after a third preset interval;

[0129] The durations of the first diffusion gradient, the second diffusion gradient, the third diffusion gradient, the fourth diffusion gradient, the fifth diffusion gradient and the sixth diffusion gradient are the same; and the first preset interval time, the second preset interval time and the third preset interval time are the same.

[0130] In one embodiment, the magnetic resonance imaging apparatus further comprises:

[0131] a third applying module, configured to apply a second excitation pulse signal to the scanned portion and apply a diffusion gradient pair to the scanned portion on each encoding axis; the second excitation pulse signal has the same amplitude and direction as the first excitation pulse signal;

[0132] a fourth applying module, configured to apply a second refocusing pulse signal to the scanning portion to obtain a second pulse signal; wherein the second refocusing pulse signal has a phase angle that is 180 degrees different from the first refocusing pulse signal;

[0133] an encoding processing module, configured to perform encoding processing on the second pulse signal to generate a second magnetic resonance signal;

[0134] The imaging module 33 includes:

[0135] The imaging unit is configured to perform magnetic resonance imaging according to the first magnetic resonance signal and the second magnetic resonance signal to obtain a magnetic resonance image of the target object.

[0136] In one embodiment, the imaging unit includes:

[0137] a first processing subunit, configured to perform averaging processing on the first magnetic resonance signal and the second magnetic resonance signal to obtain an average signal;

[0138] The second processing subunit is configured to process the average signal to obtain a magnetic resonance image of the target object.

[0139] In one embodiment, the encoding axes include a first phase encoding axis, a second phase encoding axis, and a frequency encoding axis, and the imaging module 33 includes:

[0140] a phase encoding processing unit, configured to apply a phase encoding gradient to a scanning region on a first phase encoding axis and a second phase encoding axis to obtain a first intermediate signal;

[0141] a frequency encoding processing unit, configured to apply a readout gradient to a scanning portion on a frequency encoding axis to obtain a second intermediate signal;

[0142] A generating unit is configured to generate a first magnetic resonance signal according to the first intermediate signal and the second intermediate signal.

[0143] Each module in the aforementioned magnetic resonance imaging apparatus may be implemented in whole or in part through software, hardware, or a combination thereof. Each module may be embedded in or independent of a processor in a computer device in the form of hardware, or may be stored in a memory in the computer device in the form of software, so that the processor can call and execute the corresponding operations of each module.

[0144] In an exemplary embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as shown in FIG. Figure 1 As shown. The computer device includes a processor, memory, an input / output interface, a communication interface, a display unit, and an input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are connected to the system bus via the input / output interface. 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 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 computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals via wired or wireless means, and the wireless means can be implemented via Wi-Fi, a mobile cellular network, near-field communication (NFC), or other technologies. When executed by the processor, the computer program implements a magnetic resonance imaging method. The display unit of the computer device is used to form a visually visible image and can be a display screen, a projection device, or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device casing, or an external keyboard, touchpad or mouse.

[0145] Those skilled in the art will understand that Figure 1 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0146] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the following steps are implemented:

[0147] Applying a first excitation pulse signal to a scanning portion of a target object using a magnetic resonance imaging device, and applying a diffusion gradient pair to the scanning portion on each encoding axis; the diffusion gradient pair includes a reverse diffusion gradient;

[0148] Applying a first focusing pulse signal to the scanning portion to obtain a first pulse signal;

[0149] The first pulse signal is coded to generate a first magnetic resonance signal, and magnetic resonance imaging is performed based on the first magnetic resonance signal to obtain a magnetic resonance image of the target object.

[0150] In one embodiment, a diffusion gradient pair is applied to the scanning region on each encoding axis, and when the processor executes the computer program, the following steps are further implemented:

[0151] Applying a first gradient on each encoding axis to a scanning region, and applying a second gradient on each encoding axis to the scanning region after a preset interval;

[0152] The second gradient and the first gradient have the same amplitude, opposite directions, and the same duration; and the preset interval time is the first time value.

[0153] In one embodiment, the encoding axes include a first phase encoding axis, a second phase encoding axis, and a frequency encoding axis. A first gradient is applied to a scanning region on each encoding axis, and after a preset interval, a second gradient is applied to the scanning region on each encoding axis. When the processor executes the computer program, the following steps are further implemented:

[0154] Applying a first diffusion gradient to a scanning region on a first phase encoding axis, and applying a second diffusion gradient after a first preset interval time;

[0155] Applying a third diffusion gradient to the scanning site on the second phase encoding axis, and applying a fourth diffusion gradient after a second preset interval time;

[0156] Applying a fifth diffusion gradient to the scanning site on the frequency encoding axis, and applying a sixth diffusion gradient after a third preset interval time;

[0157] The durations of the first diffusion gradient, the second diffusion gradient, the third diffusion gradient, the fourth diffusion gradient, the fifth diffusion gradient and the sixth diffusion gradient are the same; and the first preset interval time, the second preset interval time and the third preset interval time are the same.

[0158] In one embodiment, when the processor executes the computer program, the processor further implements the following steps:

[0159] Applying a second excitation pulse signal to the scanned area, and applying a diffusion gradient pair to the scanned area on each encoding axis; the second excitation pulse signal has the same amplitude and direction as the first excitation pulse signal;

[0160] Applying a second focusing pulse signal to the scanning portion to obtain a second pulse signal; the second focusing pulse signal and the first focusing pulse signal have a phase angle difference of 180 degrees;

[0161] performing encoding processing on the second pulse signal to generate a second magnetic resonance signal;

[0162] Magnetic resonance imaging is performed according to the first magnetic resonance signal to obtain a magnetic resonance image of the target object. When the processor executes the computer program, the following steps are further implemented:

[0163] Magnetic resonance imaging is performed based on the first magnetic resonance signal and the second magnetic resonance signal to obtain a magnetic resonance image of the target object.

[0164] In one embodiment, magnetic resonance imaging is performed based on the first magnetic resonance signal and the second magnetic resonance signal to obtain a magnetic resonance image of the target object. When the processor executes the computer program, the processor further implements the following steps:

[0165] performing averaging processing on the first magnetic resonance signal and the second magnetic resonance signal to obtain an average signal;

[0166] The average signal is processed to obtain a magnetic resonance image of the target object.

[0167] In one embodiment, the encoding axis includes a first phase encoding axis, a second phase encoding axis, and a frequency encoding axis. The first pulse signal is encoded to generate a first magnetic resonance signal. When the processor executes the computer program, the processor further implements the following steps:

[0168] Applying a phase encoding gradient on a first phase encoding axis and a second phase encoding axis to a scanning region to obtain a first intermediate signal;

[0169] Applying a readout gradient to the scanning position on the frequency encoding axis to obtain a second intermediate signal;

[0170] A first magnetic resonance signal is generated based on the first intermediate signal and the second intermediate signal.

[0171] 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 steps of the image processing method in any of the above embodiments are implemented.

[0172] In one embodiment, a computer program product is provided, comprising a computer program, which implements the steps of the image processing method in any of the above embodiments when executed by a processor.

[0173] It should be noted that the user information (including but not limited to relevant information of the target object, user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0174] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the 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-mentioned methods. Among them, any reference to memory, database or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the various embodiments provided herein may be, but are not limited to, general-purpose processors, central processing units (CPUs), graphics processing units (GPUs), digital signal processors (DSPs), programmable logic devices (PLDs), quantum computing-based data processing logic devices, artificial intelligence (AI) processors, and the like.

[0175] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, 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, they should be considered to be within the scope of this application.

[0176] The above embodiments merely illustrate several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A magnetic resonance imaging method, characterized in that: The method comprises: Applying a first excitation pulse signal to a scanning portion of a target object using a magnetic resonance imaging device, and applying a diffusion gradient pair to the scanning portion on each encoding axis; the diffusion gradient pair includes a reverse diffusion gradient; applying the first focusing pulse signal to the scanning part to obtain a first pulse signal; The first pulse signal is coded to generate a first magnetic resonance signal, and magnetic resonance imaging is performed based on the first magnetic resonance signal to obtain a magnetic resonance image of the target object.

2. The method according to claim 1, characterized in that Applying a diffusion gradient pair on each encoding axis to the scanning region includes: Applying a first gradient on each encoding axis for the scanning site, and applying a second gradient on each encoding axis for the scanning site after a preset interval; The second gradient and the first gradient have the same amplitude, opposite directions, and the same duration; and the preset interval time is the first time value.

3. The method according to claim 2, characterized in that The encoding axes include a first phase encoding axis, a second phase encoding axis, and a frequency encoding axis. Applying a first gradient on each encoding axis for the scanning site, and applying a second gradient on each encoding axis for the scanning site after a preset interval time, comprises: Applying a first diffusion gradient to the scanning region on the first phase encoding axis, and applying a second diffusion gradient after a first preset interval time; Applying a third diffusion gradient to the scanning region on the second phase encoding axis, and applying a fourth diffusion gradient after a second preset interval; applying a fifth diffusion gradient to the scanning region on the frequency encoding axis, and applying a sixth diffusion gradient after a third preset interval time; The durations of the first diffusion gradient, the second diffusion gradient, the third diffusion gradient, the fourth diffusion gradient, the fifth diffusion gradient, and the sixth diffusion gradient are the same; and the first preset interval time, the second preset interval time, and the third preset interval time are the same.

4. The method according to any one of claims 1 to 3, characterized in that The method further comprises: Applying a second excitation pulse signal to the scanning site, and applying the diffusion gradient pair to the scanning site on each of the encoding axes; the second excitation pulse signal has the same amplitude and direction as the first excitation pulse signal; applying the second refocusing pulse signal to the scanning part to obtain a second pulse signal; the second refocusing pulse signal and the first refocusing pulse signal have a phase angle difference of 180 degrees; performing encoding processing on the second pulse signal to generate a second magnetic resonance signal; The performing magnetic resonance imaging according to the first magnetic resonance signal to obtain a magnetic resonance image of the target object includes: Magnetic resonance imaging is performed according to the first magnetic resonance signal and the second magnetic resonance signal to obtain a magnetic resonance image of the target object.

5. The method according to claim 4, characterized in that The performing magnetic resonance imaging according to the first magnetic resonance signal and the second magnetic resonance signal to obtain a magnetic resonance image of the target object includes: performing averaging processing on the first magnetic resonance signal and the second magnetic resonance signal to obtain an average signal; The average signal is processed to obtain a magnetic resonance image of the target object.

6. The method according to any one of claims 1 to 3, characterized in that The encoding axis includes a first phase encoding axis, a second phase encoding axis, and a frequency encoding axis. The encoding process of the first pulse signal to generate a first magnetic resonance signal includes: Applying a phase encoding gradient on the first phase encoding axis and the second phase encoding axis to the scanning position to obtain a first intermediate signal; Applying a readout gradient on the frequency encoding axis to the scanning position to obtain a second intermediate signal; The first magnetic resonance signal is generated based on the first intermediate signal and the second intermediate signal.

7. A magnetic resonance imaging apparatus, characterized in that: The device comprises: a first applying module, configured to apply a first excitation pulse signal to a scanning portion of a target object using a magnetic resonance imaging device, and apply a diffusion gradient pair to the scanning portion on each encoding axis; the diffusion gradient pair includes a reverse diffusion gradient; a second applying module, configured to apply the first focusing pulse signal to the scanning part to obtain a first pulse signal; The imaging module is configured to perform encoding processing on the first pulse signal to generate a first magnetic resonance signal, and perform magnetic resonance imaging based on the first magnetic resonance signal to obtain a magnetic resonance image of the target object.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A magnetic resonance imaging system, characterized in that: The magnetic resonance imaging system comprises a magnetic resonance imaging device and a computer device, wherein the magnetic resonance imaging device is connected to the computer device, and the computer device is configured to execute the steps of the method according to any one of claims 1 to 6.

Images