Spin echo magnetic resonance acoustic radiation force imaging method, apparatus, device, and medium

Abstract

Embodiments of the present application disclose a spin echo magnetic resonance acoustic radiation force imaging method, device, equipment and medium, wherein the method comprises: applying a spin echo magnetic resonance acoustic radiation force imaging sequence provided with an eddy current matching gradient to a preset imaging object, and collecting magnetic resonance imaging data in an ultrasonic signal opening state; calculating tissue displacement phase data of the preset imaging object in a data collection stage according to the magnetic resonance imaging data; performing image reconstruction based on the tissue displacement phase data to obtain a target tissue displacement map; the eddy current matching gradient is arranged before a first motion encoding gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence; the problem of long imaging time in spin echo magnetic resonance acoustic radiation force imaging is solved, the target image can be obtained without collecting data in an ultrasonic signal pulse closing state, and the spin echo magnetic resonance acoustic radiation force imaging time can be greatly reduced.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of medical imaging technology, and in particular to a spin-echo magnetic resonance acoustic radiation force imaging method, apparatus, device and medium. Background Technology

[0002] Magnetic resonance acoustic radiation force imaging (MRI) is a technique for guiding and monitoring ultrasound signal neuromodulation. By measuring the micrometer-level displacement caused by ultrasound signal pulses in tissues, it precisely locates the point of action of ultrasound signal neuromodulation, effectively addressing the safety and effectiveness issues of ultrasound signal neuromodulation. Traditional spin-echo MRI offers advantages such as high signal-to-noise ratio and good tissue contrast; however, the need to acquire ultrasound signal pulse shutdown data to correct eddy currents results in a long imaging time, severely hindering its clinical application.

[0003] In existing technologies, the sampling of some data is reduced to decrease imaging time. Then, an iterative reconstruction algorithm is used to recover the undersampled data and perform image reconstruction to obtain spin-echo magnetic resonance acoustic radiation force imaging. However, the imaging time reduction achieved by existing imaging methods is limited, and iterative image reconstruction algorithms are still required. The reconstruction time depends on the algorithm efficiency and hardware performance, and cannot effectively and significantly reduce imaging time. Summary of the Invention

[0004] This invention provides a spin echo magnetic resonance acoustic radiation force imaging method, apparatus, device, and medium, which enables the acquisition of magnetic resonance data only when the ultrasound signal is on during spin echo magnetic resonance acoustic radiation force imaging, eliminating the need to acquire image data when the ultrasound signal is off. Image reconstruction can be performed directly based on the sampling data during the ultrasound signal on-stage, significantly reducing the spin echo magnetic resonance acoustic radiation force imaging time.

[0005] In a first aspect, embodiments of the present invention provide a spin-echo magnetic resonance acoustic radiation force imaging method, the method comprising:

[0006] A spin-echo magnetic resonance acoustic radiation force imaging sequence with eddy current matching gradient is applied to a preset imaging object, and magnetic resonance imaging data is acquired with the ultrasound signal on.

[0007] Calculate the tissue displacement phase data of the preset imaging object during the data acquisition phase based on the magnetic resonance imaging data;

[0008] Image reconstruction based on the tissue displacement phase data yields a target tissue displacement map.

[0009] The eddy current matching gradient is set before the first motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence to counteract the eddy current distortion caused by the motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence.

[0010] Secondly, embodiments of the present invention also provide a spin-echo magnetic resonance acoustic radiation force imaging device, the device comprising:

[0011] A spin-echo magnetic resonance acoustic radiation force imaging sequence with eddy current matching gradient is applied to a preset imaging object, and magnetic resonance imaging data is acquired with the ultrasound signal on.

[0012] Calculate the tissue displacement phase data of the preset imaging object during the data acquisition phase based on the magnetic resonance imaging data;

[0013] Image reconstruction based on the tissue displacement phase data yields a target tissue displacement map.

[0014] The eddy current matching gradient is set before the first motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence to counteract the eddy current distortion caused by the motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence.

[0015] Thirdly, embodiments of the present invention also provide a computer device, the computer device comprising:

[0016] One or more processors;

[0017] Memory, used to store one or more programs;

[0018] When the one or more programs are executed by the one or more processors, the one or more processors implement a spin echo magnetic resonance acoustic radiation force imaging method as provided in any embodiment of the present invention.

[0019] Fourthly, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a spin-echo magnetic resonance acoustic radiation force imaging method as provided in any embodiment of the present invention.

[0020] The embodiments of the above invention have the following advantages or beneficial effects:

[0021] This invention, in its embodiment, applies a spin-echo magnetic resonance imaging (MRI) sequence with an eddy current matching gradient to a preset imaging object and acquires MRI data while the ultrasound signal is on. Then, it calculates tissue displacement phase data of the preset imaging object during the data acquisition phase based on the MRI data. Finally, it directly reconstructs the target tissue displacement map based on the tissue displacement phase data. The eddy current matching gradient is set before the first motion-coded gradient in the spin-echo MRI sequence, thus canceling out the eddy current distortion of the motion-coded gradient caused by the motion-coded gradient in the sequence itself, eliminating the need to acquire data for eddy current correction when the ultrasound signal is off. This invention solves the problem of long imaging time in spin-echo MRI, enabling the acquisition of MRI data only when the ultrasound signal is on, eliminating the need to acquire image data when the ultrasound signal is off. Image reconstruction can be directly performed based on the sampling data from the ultrasound signal on phase, significantly reducing the spin-echo MRI time. Attached Figure Description

[0022] Figure 1 This is a flowchart of a spin-echo magnetic resonance acoustic radiation force imaging method provided in Embodiment 1 of the present invention;

[0023] Figure 2 This is a schematic diagram of a spin echo magnetic resonance acoustic radiation force imaging sequence in the prior art, provided in Embodiment 1 of the present invention;

[0024] Figure 3 This is a schematic diagram of eddy current distortion in a spin echo magnetic resonance acoustic radiation force imaging sequence in the prior art, provided in Embodiment 1 of the present invention;

[0025] Figure 4 This is a schematic diagram of eddy current distortion in a spin echo magnetic resonance acoustic radiation force imaging sequence with eddy current matching gradient provided in Embodiment 1 of the present invention.

[0026] Figure 5 This is a comparative schematic diagram of the application example of the spin echo magnetic resonance acoustic radiation force imaging method provided in Embodiment 2 of the present invention;

[0027] Figure 6 This is a comparative schematic diagram of the application example of another spin echo magnetic resonance acoustic radiation force imaging method provided in Embodiment 2 of the present invention;

[0028] Figure 7 This is a schematic diagram of the structure of a spin echo magnetic resonance acoustic radiation force imaging device provided in Embodiment 3 of the present invention;

[0029] Figure 8This is a schematic diagram of the structure of a computer device provided in Embodiment 4 of the present invention. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0031] Example 1

[0032] Figure 1 This is a flowchart of a spin-echo magnetic resonance acoustic radiation force imaging method provided in Embodiment 1 of the present invention. This embodiment is applicable to spin-echo magnetic resonance acoustic radiation force imaging, and can also be used in other imaging scenarios where the imaging sequence is affected by eddy current distortion. The method can be executed by a spin-echo magnetic resonance acoustic radiation force imaging device, which can be implemented in software and / or hardware and integrated into a computer device with application development capabilities.

[0033] like Figure 1 As shown, the spin echo magnetic resonance acoustic radiation force imaging method includes the following steps:

[0034] S110. Apply a spin-echo magnetic resonance acoustic radiation force imaging sequence with eddy current matching gradient to a preset imaging target, and acquire magnetic resonance imaging data with the ultrasound signal on.

[0035] In spin echo magnetic resonance acoustic radiation force imaging, conventional spin echo magnetic resonance acoustic radiation force imaging sequences can be referenced. Figure 2 The sequence diagram shown is an example using only one sequence from a TR. Figure 2 In this method, a motion-coded gradient with a large amplitude and rapidly switching polarity is used to capture the displacement information of the scanned object (imaging object). This motion-coded gradient induces eddy currents in the conductive structure of the magnetic resonance scanner, thereby generating an unwanted, slowly decaying magnetic field. An additional magnetic field can cause geometric distortion of subsequent gradients. (See attached image.) Figure 3The diagram illustrates eddy current distortion in spin-echo magnetic resonance imaging (SMRI). The magnetic field generated by the rapid switching of the first motion-coded gradient leads to distortion of the second motion-coded gradient, preventing it from fully converging. This is equivalent to applying an additional gradient, thus affecting the imaging results. Therefore, conventional spin-echo magnetic resonance imaging requires acquiring four repetition times (TRs). The data from TR3 and TR4, which occur during the ultrasound signal pulse-off phase, are used for eddy current correction of the TR1 and TR2 data during image reconstruction. This results in a longer imaging process, which is not conducive to clinical application.

[0036] In this embodiment, the spin echo magnetic resonance acoustic radiation force imaging sequence was adjusted by adding an eddy current matching gradient to the conventional spin echo magnetic resonance acoustic radiation force imaging sequence. Specifically, the eddy current matching gradient is set before the first motion-coded gradient in the conventional spin echo magnetic resonance acoustic radiation force imaging sequence to induce eddy current distortion in all motion-coded gradients in the spin echo magnetic resonance acoustic radiation force imaging sequence. (Refer to...) Figure 4 The diagram shown is an example using only one sequence in a TR. Figure 4 As shown, an eddy current matching gradient is added during the data acquisition phase of spin echo magnetic resonance acoustic radiation force imaging when the ultrasound signal pulse is activated. The rapid switching of this eddy current matching gradient also induces eddies, resulting in a magnetic field that forms an additional gradient at the first motion-coded gradient (indicated by the dashed line). Under the action of a 180° radio frequency pulse, an additional gradient is formed at the first motion-coded gradient, i.e., eddy current distortion. This eddy current distortion is opposite in direction to the additional gradient formed at the second motion-coded gradient by the eddies induced by the first motion-coded gradient. To a certain extent, this can cancel out the eddy current distortion, thus eliminating the need for eddy current correction when the ultrasound signal pulse is deactivated, thereby reducing sampling time.

[0037] In a preferred embodiment, the eddy current matching gradient can be set to have the same shape, magnitude, and polarity as each motion-coded gradient in the spin-echo magnetic resonance imaging (SMRI) sequence. Furthermore, the time interval between the eddy current matching gradient and the first motion-coded gradient is the same as the time interval between the first motion-coded gradient and the second motion-coded gradient in the SMRI sequence. This ensures that the additional gradient formed at the first motion-coded gradient and the additional gradient formed at the second motion-coded gradient are as close in value as possible, and can be considered equal. Therefore, during sampling, only the MRI data at the start of the ultrasound signal for two TRs needs to be sampled.

[0038] S120. Calculate the tissue displacement phase data of the preset imaging object during the data acquisition stage based on the magnetic resonance imaging data.

[0039] Based on the attached Figure 4 The adjusted spin-echo magnetic resonance acoustic radiation force imaging sequence shown exhibits eddy current matching gradients with shape, magnitude, and polarity perfectly consistent with the motion-coded gradients. Furthermore, the distance from the eddy current-coded gradient to the first motion-coded gradient is equal to the distance between the first and second motion-coded gradients. An additional gradient is formed at the first motion-coded gradient, identical to the additional gradient formed at the second motion-coded gradient. Due to the presence of the 180° radio frequency pulse, the phase directions of the two additional gradients are opposite, which can be expressed as: Among them, among them, This is due to the additional gradient generated by the eddies; It is the extra phase at the first motion-encoded gradient; It is the extra phase at the second motion coding gradient; γ represents the proton displacement; t represents the encoding duration; and γ represents the gyromagnetic ratio. Two additional phases of equal magnitude and opposite direction can cancel each other out. Therefore, the additional phase caused by eddy currents can be eliminated during the ultrasound signal pulse activation data acquisition phase, eliminating the need for ultrasound signal pulse deactivation data acquisition for correction. Thus, the magnetic resonance imaging (MRI) data can be processed to determine the average tissue displacement of the preset imaging object during the data acquisition phase based on the data phases corresponding to ultrasound signal activation and positive motion coding gradient polarity, and ultrasound signal activation and negative motion coding gradient polarity, as well as the amplitude and encoding duration of each motion coding gradient. Specifically, the phase difference between the data phases with ultrasound signal activation and positive motion coding gradient polarity and those with ultrasound signal activation and negative motion coding gradient polarity can be calculated first. Then, half of the ratio of the phase difference to the amplitude, encoding duration, and gyromagnetic ratio of the motion coding gradient can be used as the average tissue displacement of the preset imaging object during the data acquisition phase. This can be expressed by the formula:

[0040] Where Δx is the average displacement during the organization coding time; The data phase is where the ultrasound signal is enabled and the motion coding gradient polarity is positive. For data phases where the ultrasound signal is enabled and the motion-coded gradient polarity is negative; G e t represents the motion coding gradient magnitude; t represents the coding duration.

[0041] S130. Based on the tissue displacement phase data, image reconstruction is performed to obtain the target tissue displacement map.

[0042] During image reconstruction, two initial reconstructed images can be obtained by reconstructing the tissue displacement phase data within different TRs. Then, the initial reconstructed images within the two repetition time intervals are interpolated to obtain the target tissue displacement map, thereby achieving the effects of removing background noise and enhancing the image. Moreover, it can accelerate the spin echo magnetic resonance acoustic radiation force imaging without relying on prior knowledge and iterative reconstruction conditions.

[0043] The technical solution of this embodiment applies a spin-echo magnetic resonance acoustic radiation force imaging sequence with an eddy current matching gradient to a preset imaging object and acquires magnetic resonance imaging data when the ultrasound signal is on. Then, it calculates the tissue displacement phase data of the preset imaging object during the data acquisition phase based on the magnetic resonance imaging data. Based on the tissue displacement phase data, it directly reconstructs the image to obtain the target tissue displacement map. The eddy current matching gradient is set before the first motion coding gradient in the spin-echo magnetic resonance acoustic radiation force imaging sequence, which can cancel the influence of the eddy current distortion caused by the motion coding gradient in the spin-echo magnetic resonance acoustic radiation force imaging sequence. Therefore, the eddy current distortion of the motion coding gradient caused by the motion coding gradient in the spin-echo magnetic resonance acoustic radiation force imaging sequence itself will be canceled, and there is no need to acquire data when the ultrasound signal is off for eddy current correction. The technical solution of this invention solves the problem of long imaging time in spin echo magnetic resonance acoustic radiation force imaging. It realizes that when performing spin echo magnetic resonance acoustic radiation force imaging, only magnetic resonance data when the ultrasonic signal is turned on needs to be collected, without the need to collect image data when the ultrasonic signal is turned off. Image reconstruction can be performed directly based on the sampling data during the ultrasonic signal-on phase, which can significantly reduce the spin echo magnetic resonance acoustic radiation force imaging time.

[0044] Example 2

[0045] Example 2 provides an application example of the spin echo magnetic resonance acoustic radiation force imaging method in the above examples to illustrate the effect of the magnetic resonance imaging method provided by the embodiments of the present invention.

[0046] To verify the feasibility of the spin-echo magnetic resonance acoustic radiation force imaging method of the present invention, verification experiments were conducted in phantom and ex vivo lean pork tissue, respectively. During the spin-echo magnetic resonance acoustic radiation force imaging process, the following imaging parameters were maintained: recovery time TR = 1000 ms, echo time TE = 46.6 ms, and imaging resolution = 2 × 2 × 5 mm. 3 The main magnetic field B0 = 3T. Experiments were conducted comparing the traditional spin-echo magnetic resonance acoustic radiation force imaging method with the spin-echo magnetic resonance acoustic radiation force imaging method proposed in this invention.

[0047] Appendix Figure 5Results of spin-echo magnetic resonance acoustic radiation force imaging experiments performed in a phantom (wherein, Figure 5 (The unit rad is a specific unit for absorbed radiation dose). Figure 5 The leftmost image in the middle shows the phase difference image obtained by sampling and reconstruction without the influence of eddy currents when the motion-coded gradient is turned off, which can be regarded as the gold standard. When only the motion-coded gradient is turned on, i.e., conventional spin-echo magnetic resonance acoustic radiation force imaging, the phase difference between the positive gradient and the negative gradient will show a result from bright to dark, and its direction changes with the direction of the motion-coded gradient. This is the effect caused by eddy currents. Figure 5 As shown in the second figure from the left. When both motion-coded gradient and eddy current matching gradient are enabled simultaneously, which is the magnetic resonance acoustic imaging method proposed in this invention, the result of subtracting the phase of the negative gradient from the phase of the positive gradient is near 0, close to the result of disabling the motion-coded gradient, as shown in the figure below. Figure 5 As shown in Figure 1 (rightmost in the middle), this illustrates that eddy current matching gradients can effectively eliminate the influence of eddies.

[0048] Appendix Figure 6 The results of spin-echo magnetic resonance imaging (SMR) of isolated lean pork were compared using coronal and transverse images. Traditional SMR methods require eddy current correction using data from samples taken with the ultrasound signal off, necessitating the use of four transverse (TR) data points. When eddy current correction is not performed using data from samples taken with the ultrasound signal on, i.e., only two TR data points from samples taken with the ultrasound signal on, a strong background appears in the reconstructed displacement map, affecting the imaging results. However, the SMR method proposed in this invention achieves results comparable to traditional methods with eddy current correction using only two TR data points from samples taken with the ultrasound signal on.

[0049] The results show that, compared with traditional spin echo magnetic resonance acoustic radiation force imaging, the spin echo magnetic resonance acoustic radiation force imaging method proposed in this invention can accelerate the imaging speed and obtain accurate tissue displacement results without relying on prior knowledge and reconstruction conditions.

[0050] Example 3

[0051] Figure 7 This is a schematic diagram of the spin echo magnetic resonance acoustic radiation force imaging device provided in Embodiment 3 of the present invention. This embodiment can be applied to spin echo magnetic resonance acoustic radiation force imaging, and can also be used in other imaging scenarios where the imaging sequence is affected by eddy current distortion. The device can be implemented by software and / or hardware and integrated into a computer device with application development capabilities.

[0052] like Figure 7 As shown, the spin echo magnetic resonance acoustic radiation force imaging device includes: a data acquisition module 210, a displacement calculation module 220, and an image generation module 230.

[0053] The data acquisition module 210 is used to apply a spin-echo magnetic resonance acoustic radiation force imaging sequence with an eddy current matching gradient to a preset imaging object and acquire magnetic resonance imaging data when the ultrasound signal is on. The displacement calculation module 220 is used to calculate the tissue displacement phase data of the preset imaging object during the data acquisition stage based on the magnetic resonance imaging data. The image generation module 230 is used to reconstruct the target tissue displacement map based on the tissue displacement phase data. The eddy current matching gradient is set before the first motion-coded gradient in the spin-echo magnetic resonance acoustic radiation force imaging sequence to counteract the influence of eddy current distortion caused by the motion-coded gradient in the spin-echo magnetic resonance acoustic radiation force imaging sequence.

[0054] The technical solution of this embodiment applies a spin-echo magnetic resonance acoustic radiation force imaging sequence with an eddy current matching gradient to a preset imaging object and acquires magnetic resonance imaging data when the ultrasound signal is on. Then, it calculates the tissue displacement phase data of the preset imaging object during the data acquisition phase based on the magnetic resonance imaging data. Based on the tissue displacement phase data, it directly reconstructs the image to obtain the target tissue displacement map. The eddy current matching gradient is set before the first motion coding gradient in the spin-echo magnetic resonance acoustic radiation force imaging sequence, which can cancel the influence of the eddy current distortion caused by the motion coding gradient in the spin-echo magnetic resonance acoustic radiation force imaging sequence. Therefore, the eddy current distortion of the motion coding gradient caused by the motion coding gradient in the spin-echo magnetic resonance acoustic radiation force imaging sequence itself will be canceled, and there is no need to acquire data when the ultrasound signal is off for eddy current correction. The technical solution of this invention solves the problem of long imaging time in spin echo magnetic resonance acoustic radiation force imaging. It realizes that when performing spin echo magnetic resonance acoustic radiation force imaging, only magnetic resonance data when the ultrasonic signal is turned on needs to be collected, without the need to collect image data when the ultrasonic signal is turned off. Image reconstruction can be performed directly based on the sampling data during the ultrasonic signal-on phase, which can significantly reduce the spin echo magnetic resonance acoustic radiation force imaging time.

[0055] Optionally, the eddy current matching gradient is a gradient that has the same shape, size, and polarity as each motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence.

[0056] Optionally, the data acquisition module 210 can be used for:

[0057] The eddy current matching gradient is applied to a preset imaging object before the first motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence, and the time interval between the eddy current matching gradient and the first motion-coded gradient is the same as the time interval between the first motion-coded gradient and the second motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence.

[0058] Optionally, the displacement calculation module 220 is specifically used for:

[0059] Based on the data phases corresponding to when the ultrasound signal is on and the motion coding gradient polarity is positive and when the ultrasound signal is on and the motion coding gradient polarity is negative in the magnetic resonance imaging data, as well as the amplitude and coding duration of each motion coding gradient, the tissue displacement phase data of the preset imaging object during the data acquisition phase are determined.

[0060] Optionally, the displacement calculation module 220 is further used for:

[0061] Calculate the phase difference between the data phase when the ultrasound signal is on and the motion coding gradient polarity is positive and the data phase when the ultrasound signal is on and the motion coding gradient polarity is negative;

[0062] Half of the ratio of the phase difference to the amplitude of the motion coding gradient, the coding duration, and the gyromagnetic ratio is taken as the average tissue displacement of the preset imaging object during the data acquisition phase.

[0063] The spin echo magnetic resonance acoustic radiation force imaging device provided in the embodiments of the present invention can execute the spin echo magnetic resonance acoustic radiation force imaging method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of executing the method.

[0064] Example 4

[0065] Figure 8 This is a schematic diagram of the structure of a computer device provided in Embodiment 4 of the present invention. Figure 8 A block diagram of an exemplary computer device 12 suitable for implementing embodiments of the present invention is shown. Figure 8 The computer device 12 shown is merely an example and should not be construed as limiting the functionality or scope of the embodiments of the present invention. The computer device 12 can be any terminal device with computing capabilities and can be connected to medical imaging equipment to directly acquire medical image data.

[0066] like Figure 8 As shown, the computer device 12 is represented in the form of a general-purpose computing device. The components of the computer device 12 may include, but are not limited to: one or more processors or processing units 16, system memory 28, and a bus 18 connecting different system components (including system memory 28 and processing unit 16).

[0067] Bus 18 represents one or more of several bus architectures, including a memory bus or memory controller, a peripheral bus, a graphics acceleration port, a processor, or a local bus using any of the various bus architectures. For example, these architectures include, but are not limited to, the Industry Standard Architecture (ISA) bus, the Micro Channel Architecture (MAC) bus, the Enhanced ISA bus, the Video Electronics Standards Association (VESA) local bus, and the Peripheral Component Interconnect (PCI) bus.

[0068] Computer device 12 typically includes a variety of computer system readable media. These media can be any available media that can be accessed by computer device 12, including volatile and non-volatile media, removable and non-removable media.

[0069] System memory 28 may include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and / or cache memory 32. Computer device 12 may further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, storage system 34 may be used to read and write non-removable, non-volatile magnetic media (…). Figure 8 Not shown; usually referred to as a "hard drive"). Although Figure 8 Not shown, a disk drive for reading and writing to a removable non-volatile disk (e.g., a "floppy disk") and an optical disk drive for reading and writing to a removable non-volatile optical disk (e.g., a CD-ROM, DVD-ROM, or other optical media) may be provided. In these cases, each drive may be connected to bus 18 via one or more data media interfaces. System memory 28 may include at least one program product having a set (e.g., at least one) of program modules configured to perform the functions of the embodiments of the present invention.

[0070] A program / utility 40 having a set (at least one) of program modules 42 may be stored, for example, in system memory 28. Such program modules 42 include, but are not limited to, an operating system, one or more application programs, other program modules, and program data. Each or some combination of these examples may include an implementation of a network environment. Program modules 42 typically perform the functions and / or methods described in the embodiments of the present invention.

[0071] Computer device 12 can also communicate with one or more external devices 14 (e.g., keyboard, pointing device, display 24, etc.), and with one or more devices that enable a user to interact with the computer device 12, and / or with any device that enables the computer device 12 to communicate with one or more other computing devices (e.g., network card, modem, etc.). This communication can be performed via input / output (I / O) interface 22. Furthermore, computer device 12 can also communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public networks, such as the Internet) via network adapter 20. As shown, network adapter 20 communicates with other modules of computer device 12 via bus 18. It should be understood that, although... Figure 8 As not shown, it can be used in conjunction with computer device 12 with other hardware and / or software modules, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0072] Processing unit 16 executes various functional applications and data processing by running programs stored in system memory 28, such as implementing the spin echo magnetic resonance acoustic radiation force imaging method provided in this embodiment, the method including:

[0073] A spin-echo magnetic resonance acoustic radiation force imaging sequence with eddy current matching gradient is applied to a preset imaging object, and magnetic resonance imaging data is acquired with the ultrasound signal on.

[0074] Calculate the tissue displacement phase data of the preset imaging object during the data acquisition phase based on the magnetic resonance imaging data;

[0075] Image reconstruction based on the tissue displacement phase data yields a target tissue displacement map.

[0076] The eddy current matching gradient is set before the first motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence to counteract the eddy current distortion caused by the motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence.

[0077] Example 5

[0078] This fifth embodiment provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the spin-echo magnetic resonance acoustic radiation force imaging method as provided in any embodiment of the present invention, including:

[0079] A spin-echo magnetic resonance acoustic radiation force imaging sequence with eddy current matching gradient is applied to a preset imaging object, and magnetic resonance imaging data is acquired with the ultrasound signal on.

[0080] Calculate the tissue displacement phase data of the preset imaging object during the data acquisition phase based on the magnetic resonance imaging data;

[0081] Image reconstruction based on the tissue displacement phase data yields a target tissue displacement map.

[0082] The eddy current matching gradient is set before the first motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence to counteract the eddy current distortion caused by the motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence.

[0083] The computer storage medium of this invention can be any combination of one or more computer-readable media. A computer-readable medium can be a computer-readable medium or a computer-readable storage medium. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0084] Computer-readable media may include data propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data may take various forms, including but not limited to electromagnetic, optical, or any suitable combination thereof. Computer-readable media may also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device.

[0085] Program code contained on a computer-readable medium may be transmitted using any suitable medium, including but not limited to: wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0086] Computer program code for performing the operations of this invention can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0087] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computing device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the present invention is not limited to any particular combination of hardware and software.

[0088] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A spin-echo magnetic resonance acoustic radiation force imaging method, characterized in that, The method includes: A spin-echo magnetic resonance acoustic radiation force imaging sequence with eddy current matching gradient is applied to a preset imaging object, and magnetic resonance imaging data is acquired only when the ultrasound signal is on. Calculate the tissue displacement phase data of the preset imaging object during the data acquisition phase based on the magnetic resonance imaging data; Image reconstruction based on the tissue displacement phase data yields a target tissue displacement map. The eddy current matching gradient is set before the first motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence to counteract the eddy current distortion caused by the motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence. The eddy current matching gradient is a gradient that has the same shape, size, and polarity as each motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence. The application of a spin-echo magnetic resonance acoustic radiation force imaging sequence with an eddy current matching gradient to a preset imaging object includes: The eddy current matching gradient is applied to a preset imaging object before the first motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence, and the time interval between the eddy current matching gradient and the first motion-coded gradient is the same as the time interval between the first motion-coded gradient and the second motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence. Under the action of a 180° radio frequency pulse, an additional gradient is formed at the first motion coding gradient, which is opposite in direction to the additional gradient formed at the second motion coding gradient by the eddy current induced by the first motion coding gradient.

2. The method according to claim 1, characterized in that, The step of calculating the tissue displacement phase data of the preset imaging object during the data acquisition phase based on the magnetic resonance imaging data includes: Based on the data phases corresponding to when the ultrasound signal is on and the motion coding gradient polarity is positive and when the ultrasound signal is on and the motion coding gradient polarity is negative in the magnetic resonance imaging data, as well as the amplitude and coding duration of each motion coding gradient, the tissue displacement phase data of the preset imaging object during the data acquisition phase are determined.

3. The method according to claim 2, characterized in that, The step of determining the tissue displacement phase data of the preset imaging object during the data acquisition phase based on the data phase corresponding to when the ultrasound signal is on and the motion coding gradient polarity is positive and the data phase corresponding to when the ultrasound signal is on and the motion coding gradient polarity is negative, as well as the amplitude and coding duration of each motion coding gradient, includes: Calculate the phase difference between the data phase when the ultrasound signal is on and the motion coding gradient polarity is positive and the data phase when the ultrasound signal is on and the motion coding gradient polarity is negative; Half of the ratio of the phase difference value to the amplitude of the motion coding gradient, the coding duration, and the gyromagnetic ratio is taken as the average tissue displacement of the preset imaging object during the data acquisition phase; this can be expressed by the formula: ,in, The average displacement over the organization's coding time; The data phase is where the ultrasound signal is enabled and the motion coding gradient polarity is positive. The data phase is where the ultrasound signal is enabled and the motion coding gradient polarity is negative. The gradient magnitude is the motion encoding value; t is the encoding duration. It is the gyromagnetic ratio.

4. A spin-echo magnetic resonance acoustic radiation force imaging device, characterized in that, The device includes: The data acquisition module is used to apply a spin-echo magnetic resonance acoustic radiation force imaging sequence with eddy current matching gradient to a preset imaging object, and only acquires magnetic resonance imaging data when the ultrasound signal is on. The displacement calculation module is used to calculate the tissue displacement phase data of the preset imaging object during the data acquisition stage based on the magnetic resonance imaging data. The image generation module is used to reconstruct the target tissue displacement map based on the tissue displacement phase data. The eddy current matching gradient is set before the first motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence to counteract the eddy current distortion caused by the motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence; the eddy current matching gradient is a gradient with the same shape, size and polarity as each motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence. The data acquisition module is specifically used to apply the eddy current matching gradient to a preset imaging object before the first motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence, and to make the time interval between the eddy current matching gradient and the first motion-coded gradient the same as the time interval between the first motion-coded gradient and the second motion-coded gradient in the spin echo magnetic resonance acoustic radiation force imaging sequence; under the action of a 180° radio frequency pulse, an additional gradient is formed at the first motion-coded gradient, which is opposite in direction to the additional gradient formed at the second motion-coded gradient by the eddy current induced by the first motion-coded gradient.

5. A computer device, characterized in that, The computer device includes: One or more processors; Memory, used to store one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the spin echo magnetic resonance acoustic radiation force imaging method as described in any one of claims 1-3.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the spin echo magnetic resonance acoustic radiation force imaging method as described in any one of claims 1-3.

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