A parallel transmission local excitation pulse generation method, device and storage medium

Abstract

The application relates to a parallel emission local excitation pulse generation method, device and storage medium, the method comprising: generating a radio frequency pulse according to a three-dimensional mapping of a test object and a three-dimensional excitation K space; calculating excitation uniformity according to the three-dimensional mapping, the three-dimensional excitation K space and the radio frequency pulse; when the excitation uniformity is less than a preset value, updating the three-dimensional mapping and the three-dimensional excitation K space used for generating the radio frequency pulse and for calculating the excitation uniformity; when the excitation uniformity is greater than or equal to the preset value, generating the parallel emission local excitation pulse according to the three-dimensional excitation K space and the radio frequency pulse currently used for calculating the excitation uniformity. Through the application, the problem that the radio frequency pulse duration is long in the prior art is solved, the local excitation position uniformity in the expected magnetic resonance emission field is achieved, and the radio frequency pulse length is shortened.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of magnetic resonance, and particularly relates to a parallel transmission local excitation pulse generation method and device and a storage medium. BACKGROUND

[0002] In imaging at ultra-high field, in order to obtain a uniform B1 field distribution, multi-channel parallel transmission is usually adopted, and the multi-channel transmission radio frequency pulse can cause the problem of transmission field non-uniformity. Meanwhile, in the process of correcting the transmission field non-uniformity and realizing uniform local excitation of part of the human body, a relatively long radio frequency pulse duration is generally required.

[0003] At present, there is no effective solution to the problem of long radio frequency pulse duration in the prior art. SUMMARY

[0004] The parallel transmission local excitation pulse generation method, device and storage medium are provided in the embodiment to solve the problem of radio frequency pulse duration in the prior art.

[0005] In a first aspect, the parallel transmission local excitation pulse generation method is provided in the embodiment, and the method comprises the following steps.

[0006] generating a radio frequency pulse according to a three-dimensional mapping diagram of a test object and a three-dimensional excitation K-space;

[0007] calculating excitation uniformity according to the three-dimensional mapping diagram, the three-dimensional excitation K-space and the radio frequency pulse;

[0008] when the excitation uniformity is less than a preset value, updating the three-dimensional mapping diagram and the three-dimensional excitation K-space used for generating the radio frequency pulse and used for calculating the excitation uniformity;

[0009] when the excitation uniformity is greater than or equal to the preset value, generating the parallel transmission local excitation pulse according to the three-dimensional excitation K-space and the radio frequency pulse currently used for calculating the excitation uniformity.

[0010] In some embodiments, when the excitation uniformity is less than a preset value, the three-dimensional mapping diagram and the three-dimensional excitation K-space used for generating the radio frequency pulse and used for calculating the excitation uniformity are updated, and the updating comprises the following steps.

[0011] reducing the sparsity of the three-dimensional excitation K-space to obtain an updated three-dimensional excitation K-space.

[0012] In some embodiments, when the excitation uniformity is less than a preset value, the updating of the three-dimensional map and the three-dimensional excitation K-space used for generating the radio frequency pulse and for calculating the excitation uniformity comprises:

[0013] The three-dimensional map is smoothed to obtain an updated three-dimensional map.

[0014] In some embodiments, the generating of the radio frequency pulse according to the three-dimensional map and the three-dimensional excitation K-space of the test object comprises:

[0015] The radio frequency pulse is generated according to the three-dimensional map, a system matrix, and an expected excitation shape; the system matrix is generated according to the three-dimensional excitation K-space.

[0016] In some embodiments, the generating of the radio frequency pulse according to the three-dimensional map and the three-dimensional excitation K-space of the test object comprises:

[0017] The radio frequency pulse is generated according to the three-dimensional map, the system matrix, an expected excitation shape, and a weight matrix; the weight matrix is determined according to the contour of the test object in the three-dimensional map and the expected excitation shape.

[0018] In some embodiments, the smoothing of the three-dimensional map to obtain an updated three-dimensional map comprises:

[0019] The amplitude and the phase of the three-dimensional map are smoothed to obtain an updated three-dimensional map.

[0020] In some embodiments, the radio frequency pulse comprises an amplitude and a phase.

[0021] The calculating of the excitation uniformity according to the three-dimensional map, the three-dimensional excitation K-space, and the radio frequency pulse comprises:

[0022] The excitation uniformity is calculated according to the three-dimensional map, the three-dimensional excitation K-space, the amplitude of the radio frequency pulse, and the phase of the radio frequency pulse.

[0023] In a second aspect, a parallel transmission local excitation pulse generating device is provided in the embodiments, and the device comprises:

[0024] A generating module is configured to generate a radio frequency pulse according to a three-dimensional map and a three-dimensional excitation K-space of a test object.

[0025] A calculating module is configured to calculate an excitation uniformity according to the three-dimensional map, the three-dimensional excitation K-space, and the radio frequency pulse.

[0026] The first execution module is configured to update the three-dimensional map and the three-dimensional excitation K-space used for generating the radio frequency pulse and for calculating the excitation uniformity when the excitation uniformity is less than the preset value;

[0027] The second execution module is configured to generate the parallel transmission local excitation pulse according to the three-dimensional excitation K-space and the radio frequency pulse currently used for calculating the excitation uniformity when the excitation uniformity is greater than or equal to the preset value.

[0028] In a third aspect, an electronic device is provided in the embodiment, which comprises a memory and a processor, the memory stores a computer program, and the processor is configured to run the computer program to execute the parallel transmission local excitation pulse generation method of the first aspect.

[0029] In a fourth aspect, a computer readable storage medium is provided in the embodiment, which stores a computer program, and the computer program is executed by a processor to implement the steps of the parallel transmission local excitation pulse generation method of the first aspect.

[0030] Compared with the prior art, the parallel transmission local excitation pulse generation method, device and storage medium provided in the embodiment calculate the excitation uniformity according to the three-dimensional map, the three-dimensional excitation K-space and the radio frequency pulse, update the three-dimensional map and the three-dimensional excitation K-space when the calculated excitation uniformity is less than the preset value, continue to iteratively generate the radio frequency pulse, further shorten the duration of the radio frequency pulse in the iteration process, and generate the parallel transmission local excitation pulse when the calculated excitation uniformity is greater than or equal to the preset value, so as to achieve the expected uniformity of the local excitation site in the magnetic resonance transmission field, while shortening the duration of the radio frequency pulse. The problem that a long radio frequency pulse duration is generally required in the process of correcting the non-uniformity of the transmission field and realizing the uniform local excitation of the part of the human body in the prior art is solved. The expected uniformity of the local excitation site in the magnetic resonance transmission field is achieved, while the duration of the radio frequency pulse is shortened.

[0031] The details of one or more embodiments of the present application are presented in the following drawings and description to make other features, objects and advantages of the present application more apparent. BRIEF DESCRIPTION OF DRAWINGS

[0032] The drawings described herein are intended to provide further understanding of the present application, form a part of the present application, and the illustrative embodiments of the present application and their descriptions are used to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0033] Figure 1 is a hardware structure block diagram of a terminal for executing a parallel transmission local excitation pulse generation method in the embodiment;

[0034] Figure 2 is a flow chart of the method for generating parallel emission local excitation pulses according to this embodiment;

[0035] Figure 3 is a preferred flow chart of the method for generating parallel emission local excitation pulses of this embodiment;

[0036] Figure 4 This is a structural block diagram of a parallel transmission local excitation pulse generating device of this embodiment. DETAILED DESCRIPTION

[0037] In order to more clearly understand the purpose, technical solutions and advantages of the present application, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0038] Unless otherwise defined, the technical terms or scientific terms involved in this application should have the general meaning understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "an", "a", "the", "these" and the like in this application do not indicate quantitative restrictions, and they can be singular or plural. The terms "include", "comprise", "have" and any variants thereof involved in this application are intended to cover non-exclusive inclusions; for example, a process, method and system, product or device comprising a series of steps or modules (units) is not limited to the listed steps or modules (units), but may include unlisted steps or modules (units), or may include other steps or modules (units) inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "plurality" involved in this application refers to two or more. "And / or" describes the relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, and B exists alone. Generally, the character " / " indicates that the related objects are in an "or" relationship. The terms "first," "second," "third," etc. used in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0039] The method embodiment provided in this embodiment can be executed in a terminal, a computer or a similar computing device. For example, running on a terminal, Figure 1 FIG. 1 is a hardware structure block diagram of a terminal that executes a method for generating a parallel transmission local excitation pulse according to this embodiment. Figure 1 As shown, the terminal may include one or more ( Figure 1The terminal shown in the figure only includes one processor 102 and a memory 104 for storing data, wherein the processor 102 can include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA. The terminal can also include a transmission device 106 for communication function and an input and output device 108. Those skilled in the art can understand that Figure 1 The structure shown in the figure is only schematic and does not limit the structure of the terminal. For example, the terminal can include more or less components than those shown in the figure, or have a different configuration from that shown in the figure. Figure 1 The terminal shown in the figure only includes one processor 102 and a memory 104 for storing data, wherein the processor 102 can include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA. The terminal can also include a transmission device 106 for communication function and an input and output device 108. Those skilled in the art can understand that Figure 1 The structure shown in the figure is only schematic and does not limit the structure of the terminal. For example, the terminal can include more or less components than those shown in the figure, or have a different configuration from that shown in the figure.

[0040] The memory 104 can be used to store computer programs, such as software programs of application software and modules, such as a computer program corresponding to a parallel emission local excitation pulse generation method in the embodiment. The processor 102 can execute various functional applications and data processing by running the computer program stored in the memory 104, that is, implement the method described above. The memory 104 can include a high-speed random access memory and can also include a non-volatile memory, such as one or more magnetic storage devices, flash memories, or other non-volatile solid-state memories. In some examples, the memory 104 can further include a memory remotely arranged with respect to the processor 102, and these remote memories can be connected to the terminal through a network. Examples of the network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof.

[0041] The transmission device 106 is used to receive or send data via a network. The network includes a wireless network provided by a communication provider of the terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, NIC for short), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (Radio Frequency, RF for short) module, which is used to communicate with the Internet in a wireless manner.

[0042] In the embodiment, a parallel emission local excitation pulse generation method is provided, Figure 2 The flowchart of the parallel emission local excitation pulse generation method of the embodiment is shown in FIG. 2, which includes the following steps: Figure 2

[0043] In step S210, a radio frequency pulse is generated according to a three-dimensional map of a test object and a three-dimensional excitation K-space.

[0044] ​Specifically, a pre-scan is performed on the test object to obtain a three-dimensional map (three-dimensional B1 map) of the test object. According to the three-dimensional map of the test object, an initial three-dimensional excitation K-space is determined; the initial three-dimensional excitation K-space has a long time-varying gradient and a large number of points. A cost function of the three-dimensional excitation K-space and the radio frequency pulse is constructed, the cost function includes information of the three-dimensional map of the test object, and the radio frequency pulse is iteratively generated using a conjugate gradient method according to the initial three-dimensional excitation K-space or the updated three-dimensional excitation K-space and the cost function. The three-dimensional map includes a three-dimensional object contour of a part to be locally excited.

[0045] In step S220, excitation uniformity is calculated according to the three-dimensional map, the three-dimensional excitation K-space, and the radio frequency pulse.

[0046] Specifically, the excitation uniformity is calculated according to the radio frequency pulse calculated in step S210, the three-dimensional map used to calculate the radio frequency pulse, and the three-dimensional excitation K-space used to calculate the radio frequency pulse. Further, the radio frequency pulse generated in step S210 includes an amplitude of the radio frequency pulse and a phase of the radio frequency pulse, and the excitation uniformity is calculated according to the three-dimensional map, the three-dimensional excitation K-space, the amplitude of the radio frequency pulse, and the phase of the radio frequency pulse.

[0047] In step S230, when the excitation uniformity is less than a preset value, the three-dimensional map and the three-dimensional excitation K-space used to generate the radio frequency pulse and to calculate the excitation uniformity are updated.

[0048] Specifically, the excitation uniformity calculated in step S220 is compared with a preset uniformity threshold value, and when the excitation uniformity is less than the preset uniformity threshold value, it indicates that the excitation uniformity generated by the three-dimensional excitation K-space at this time cannot meet the requirements, and the three-dimensional map and the three-dimensional excitation K-space used to generate the radio frequency pulse and to calculate the excitation uniformity are updated.

[0049] Further specifically, after the three-dimensional map and the three-dimensional excitation K-space used to generate the radio frequency pulse and to calculate the excitation uniformity are updated, step S210 is performed.

[0050] In step S240, when the excitation uniformity is greater than or equal to a preset value, a parallel transmission local excitation pulse is generated according to the current three-dimensional excitation K-space and the radio frequency pulse used to calculate the excitation uniformity.

[0051] Specifically, the calculated excitation uniformity in step S220 is compared with a preset uniformity threshold, and when the excitation uniformity is greater than or equal to the preset uniformity threshold, it is indicated that the excitation uniformity generated by the generated three-dimensional excitation K-space satisfies the requirement, and then a parallel transmission local excitation pulse is generated according to the three-dimensional excitation K-space and the radio frequency pulse currently used for calculating the excitation uniformity, and a local excitation uniform field is generated by using the parallel transmission mode.

[0052] Further specifically, according to the three-dimensional mapping of the test object, the three-dimensional overall profile of the test object is obtained, a part needing local excitation is selected, and a parallel transmission local excitation pulse is generated according to the three-dimensional excitation K-space and the radio frequency pulse currently used for calculating the excitation uniformity, and a local excitation uniform field of the part needing local excitation is generated by using the parallel transmission mode.

[0053] In the embodiment, the excitation uniformity is calculated according to the three-dimensional mapping, the three-dimensional excitation K-space and the radio frequency pulse, when the calculated excitation uniformity is less than a preset value, the three-dimensional mapping and the three-dimensional excitation K-space are updated, and the iteration of generating the radio frequency pulse is continued, in the process of iteration, the length of the radio frequency pulse is further shortened, until the calculated excitation uniformity is greater than or equal to the preset value, and a parallel transmission local excitation pulse is generated, so as to achieve the purpose of shortening the length of the radio frequency pulse and the uniformity of the local excitation part in the expected magnetic resonance transmission field.

[0054] In some embodiments, updating the three-dimensional mapping and the three-dimensional excitation K-space used for generating the radio frequency pulse and for calculating the excitation uniformity includes: reducing the sparsity of the three-dimensional excitation K-space to obtain an updated three-dimensional excitation K-space; and smoothing the three-dimensional mapping to obtain an updated three-dimensional mapping, and further, smoothing the amplitude and phase of the three-dimensional mapping to obtain an updated three-dimensional mapping.

[0055] In some embodiments, generating the radio frequency pulse according to the three-dimensional mapping and the three-dimensional excitation K-space of the test object includes: generating the radio frequency pulse according to the three-dimensional mapping, a system matrix and an expected excitation shape; and the system matrix is generated according to the three-dimensional excitation K-space.

[0056] Specifically, the radio frequency pulse is generated according to the three-dimensional mapping, a system matrix, an expected excitation shape and a weight matrix, and the weight matrix is determined according to the profile of the test object in the three-dimensional mapping and the expected excitation shape; the profile of the test object in the three-dimensional mapping here can be the profile of the part needing local excitation, and the expected excitation shape here is the planar shape that is expected to be excited.

[0057] The embodiment will be described and explained below through preferred embodiments.

[0058] Figure 3is a preferred flow chart of the parallel transmit local excitation pulse generation method of the present embodiment, as shown in Figure 3 The row transmit local excitation pulse generation method comprises the following steps:

[0059] Step S310, acquire a three-dimensional B1 map.

[0060] Specifically, a pre-scan is performed on the object, a three-dimensional B1 map of the object within the field of view of the receiving coil is acquired, and the amplitude and phase information of the three-dimensional B1 map is obtained.

[0061] Step S320, obtain the contour of the object and select the local excitation site.

[0062] Specifically, the three-dimensional overall contour of the object is obtained according to the three-dimensional B1 map, and the contour of the site to be locally excited is set. The three-dimensional overall contour of the object is obtained by B1 map acquisition, and the distribution information of the contour and the excitation field (generated by radio frequency) is obtained.

[0063] Step S330, set an initial three-dimensional excitation K-space and construct a cost function.

[0064] Specifically, the cost function of the constructed three-dimensional excitation K-space and the radio frequency pulse is shown in formula (1).

[0065]

[0066] Wherein, argmin(·) is the minimum value function, b is the duration of the radio frequency pulse, N t is the duration of the radio frequency pulse, N c is the radio frequency pulse channel, k is the final obtained three-dimensional excitation K-space, A = iγexp(i2π(xk x +yk y +zk z )) is a system matrix, which is determined by the excitation k-space (k x ,k y ,k z ) generated by each iteration, γ is the gyromagnetic ratio, which is a fixed constant, S is the acquired three-dimensional B1 map, and the smoothness of the three-dimensional B1 map needs to be adjusted in actual iteration, λ is a regularization coefficient, and the number 8 is usually used, is a weighted 2-norm, the weighting matrix is W, W is a weight matrix, which is used to weigh the weight of the excitation region and the non-excitation region, ||·||2 is a 2-norm. d is the expected local excitation shape, which is determined by the selected shape mask and the folding angle α, specifically, d can be obtained according to formula (2).

[0067] d = mask·sinα (2)

[0068] Wherein, the selected shape mask refers to the planar shape that is desired to be excited to form, which can be a square, a circle or any simple convex shape, and the folding angle a refers to the folding angle of the radio frequency pulse, which is an inherent attribute of the radio frequency pulse.

[0069] The three-dimensional excitation K-space refers to the Fourier transform of the gradient applied simultaneously with the radio frequency pulse. When the three-dimensional excitation K-space is obtained, the three-dimensional B1 map and the linear product of the system matrix A and the radio frequency pulse are the expected excitation relationship. The three-dimensional excitation K-space is used for excitation, and the excitation effect is that a better excitation uniform field can be achieved in the selected three-dimensional excitation region.

[0070] Step S340, generating a radio frequency pulse, calculating the excitation uniformity.

[0071] Specifically, the conjugate gradient method is used to iteratively obtain the amplitude and phase of the radio frequency pulse, and the excitation uniformity is calculated. For the cost function, a joint optimization method is used, that is, the three-dimensional excitation K-space and the radio frequency pulse are jointly optimized. First, the weight matrix W is determined according to the three-dimensional object contour of the part to be locally excited and the selected shape mask. A longer time-varying gradient is designed according to the size of the object field, so as to generate a three-dimensional excitation K-space with more points. Then, the three-dimensional excitation K-space and the cost function are used to generate the radio frequency pulse b by using the conjugate gradient method. The excitation uniformity is calculated according to the radio frequency pulse, the three-dimensional B1 map and the three-dimensional excitation K-space. Specifically, the excitation uniformity can be calculated by formula (3).

[0072]

[0073] Wherein, m is the excitation uniformity, norm(·) is a normalization function, is the square of the 2-norm, b is the radio frequency pulse, N t is the duration of the radio frequency pulse, N c is the radio frequency pulse channel, A = iγexp(i2π(xk x +yk y +zk z )) is the system matrix, which is determined by the excitation k-space (k x ,k y ,k z ) generated by each iteration, γ is the gyromagnetic ratio, which is a fixed constant, S is the three-dimensional B1 map acquired, d is the shape of the expected local excitation, which is determined by the selected shape mask and the folding angle a. Specifically, d can be obtained according to formula (2).

[0074] Step S350, judging whether the excitation uniformity is less than a preset index. If yes, step S360 is executed; if no, step S370 is executed.

[0075] Specifically, the acceptable expected excitation uniformity is preset to evaluate the acceptance degree of the expected excitation effect, and if the combination of the short local excitation pulse and the time-varying gradient can meet the requirement of the expected uniformity, the iteration stops. It is judged whether the calculated excitation uniformity is less than the preset index, if yes, the sparsity of the three-dimensional excitation K-space is reduced, thereby reducing the number of three-dimensional excitation K-space points, slightly smoothing the amplitude information and phase information of the three-dimensional B1 map, calculating the radio frequency pulse with a shorter length according to the three-dimensional excitation K-space with fewer points, and then continuing to calculate the excitation uniformity, and the iteration continues, and the radio frequency pulse and the time-varying gradient can be further shortened. If not, the three-dimensional excitation K-space and the radio frequency pulse that meet the requirement of the excitation uniformity in the last iteration are used to generate a local excitation uniform field in a parallel transmission mode.

[0076] In step S360, the three-dimensional excitation K-space is thinned, and the three-dimensional B1 map is smoothed, and step S340 is executed.

[0077] Specifically, the actual acquired three-dimensional B1 map needs to be smoothed and approximated in the iteration process, and the smoothing degree can be continuously adjusted in the iteration process. If the iteration continues, the radio frequency pulse is regenerated by thinning the three-dimensional excitation K-space (fov field of view) and smoothing the three-dimensional B1 map, and the excitation uniformity is calculated and compared with the preset value again.

[0078] In step S370, the three-dimensional excitation K-space and the radio frequency pulse of the last iteration are used to transmit a three-dimensional parallel transmission pulse, and a three-dimensional GRE sequence is used for acquisition.

[0079] Specifically, the three-dimensional excitation K-space and the radio frequency pulse of the last iteration are used to transmit a three-dimensional parallel transmission pulse, and a three-dimensional GRE sequence (gradient recalled echo) is used for acquisition. When the excitation uniformity is greater than or equal to the preset value, it indicates that the excitation uniformity generated by the three-dimensional excitation K-space at this time meets the requirement, and then the parallel transmission local excitation pulse is generated according to the three-dimensional excitation K-space and the radio frequency pulse of the last iteration, and a local excitation uniform field of the selected local excitation site is generated in a parallel transmission mode.

[0080] In the embodiment, the excitation uniformity is calculated according to the three-dimensional map, the three-dimensional excitation K-space and the radio frequency pulse, when the calculated excitation uniformity is less than the preset value, the three-dimensional map and the three-dimensional excitation K-space are updated, and the iteration of generating the radio frequency pulse continues, in the iteration process, the length of the radio frequency pulse is further shortened, until the calculated excitation uniformity is greater than or equal to the preset value, and the parallel transmission local excitation pulse is generated, to achieve the expected local excitation site uniformity in the magnetic resonance transmission field, and the purpose of shortening the length of the radio frequency pulse.

[0081] A parallel transmission local excitation pulse generation apparatus is also provided in the embodiment, which is used to implement the above-mentioned embodiments and preferred embodiments, and will not be described again. The terms "module", "unit", "sub-unit" and the like used below can be a combination of software and / or hardware that implements a predetermined function. Although the apparatus described in the following embodiments is preferably implemented in software, implementation of hardware, or a combination of software and hardware, is also possible and contemplated.

[0082] Figure 4 is a structural block diagram of a parallel transmission local excitation pulse generation apparatus of the embodiment, as Figure 4 shown, the apparatus comprises:

[0083] The generating module 410 is configured to generate a radio frequency pulse according to a three-dimensional mapping of a test object and a three-dimensional excitation K-space.

[0084] The calculating module 420 is configured to calculate excitation uniformity according to the three-dimensional mapping, the three-dimensional excitation K-space and the radio frequency pulse.

[0085] The first executing module 430 is configured to update the three-dimensional mapping and the three-dimensional excitation K-space used to generate the radio frequency pulse and used to calculate the excitation uniformity when the excitation uniformity is less than a preset value.

[0086] The second executing module 440 is configured to generate a parallel transmission local excitation pulse according to the three-dimensional excitation K-space and the radio frequency pulse currently used to calculate the excitation uniformity when the excitation uniformity is greater than or equal to the preset value.

[0087] It should be noted that each of the above modules can be a functional module or a program module, and can be implemented by software or hardware. For the modules implemented by hardware, each of the above modules can be located in the same processor; or each of the above modules can also be located in different processors in any combination.

[0088] An electronic device is also provided in the embodiment, comprising a memory and a processor, the memory stores a computer program, and the processor is configured to run the computer program to perform the steps in any of the above method embodiments.

[0089] Optionally, the electronic device can further comprise a transmission device and an input and output device, wherein the transmission device is connected with the processor, and the input and output device is connected with the processor.

[0090] Optionally, in the embodiment, the processor can be configured to perform the following steps through the computer program:

[0091] S1, generating a radio frequency pulse according to a three-dimensional mapping of a test object and a three-dimensional excitation K-space;

[0092] S2, calculating excitation uniformity according to the three-dimensional mapping, the three-dimensional excitation K-space and the radio frequency pulse;

[0093] S3, when the excitation uniformity is less than a preset value, updating the three-dimensional mapping and the three-dimensional excitation K-space used for generating the radio frequency pulse and for calculating the excitation uniformity;

[0094] S4, when the excitation uniformity is greater than or equal to the preset value, generating a parallel transmission local excitation pulse according to the current three-dimensional excitation K-space and the radio frequency pulse used for calculating the excitation uniformity.

[0095] It should be noted that the specific examples in the embodiment can refer to the examples described in the above embodiments and optional implementation manners, which will not be described herein again.

[0096] In addition, in combination with the parallel transmission local excitation pulse generation method provided in the above embodiments, a storage medium can also be provided to implement the parallel transmission local excitation pulse generation method in the embodiment. The storage medium has a computer program stored thereon. When the computer program is executed by a processor, the steps of any one of the parallel transmission local excitation pulse generation methods in the above embodiments are implemented.

[0097] It should be understood that the specific embodiments described herein are only used to explain this application, but not to limit it. According to the embodiments provided in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0098] Obviously, the drawings are only some examples or embodiments of the present application, and can be applied to other similar situations without creative labor for those of ordinary skill in the art. In addition, it can be understood that although the work done in the development process may be complex and long, some design, manufacture or production changes according to the technical content disclosed in the present application are only conventional technical means for those of ordinary skill in the art, and should not be regarded as insufficient disclosure of the present application.

[0099] The term "embodiment" in the present application means that the specific features, structures or characteristics described in combination with the embodiment can 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 mean the same embodiment, nor does it mean independence or alternative to other embodiments. Those of ordinary skill in the art can clearly or implicitly understand that the embodiments described in the present application can be combined with other embodiments without conflict.

[0100] The above-described embodiments are merely illustrative of several embodiments of the present application, which are described in more detail and in a specific manner, but should not be construed as limiting the scope of patent protection. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A method for generating parallel emission local excitation pulses, characterized in that: The method comprises: Generate radio frequency pulses based on the three-dimensional map of the test object and the three-dimensional excitation K space; Calculating excitation uniformity based on the three-dimensional mapping image, the three-dimensional excitation K space, and the radio frequency pulse; When the excitation uniformity is less than a preset value, updating the three-dimensional mapping diagram and the three-dimensional excitation K space used for generating the radio frequency pulse and for calculating the excitation uniformity; When the excitation uniformity is greater than or equal to the preset value, generating the parallel transmission local excitation pulses according to the three-dimensional excitation K space and the radio frequency pulse currently used to calculate the excitation uniformity; When the excitation uniformity is less than a preset value, the three-dimensional mapping diagram and the three-dimensional excitation K space used to generate the radio frequency pulse and calculate the excitation uniformity are updated, including: reducing the sparsity of the three-dimensional excitation K space to obtain an updated three-dimensional excitation K space.

2. The method for generating parallel emission local excitation pulses according to claim 1, wherein: When the excitation uniformity is less than a preset value, updating the three-dimensional mapping diagram and the three-dimensional excitation K space used for generating the radio frequency pulse and for calculating the excitation uniformity includes: The three-dimensional map is smoothed to obtain an updated three-dimensional map.

3. The method for generating parallel emission local excitation pulses according to claim 1, wherein: Generating radio frequency pulses according to the three-dimensional mapping diagram and the three-dimensional excitation K space of the test object includes: The radio frequency pulse is generated according to the three-dimensional mapping diagram, the system matrix and the expected excitation shape; the system matrix is ​​generated according to the three-dimensional excitation K space.

4. The method for generating parallel emission local excitation pulses according to claim 3, wherein: Generating radio frequency pulses according to the three-dimensional mapping diagram and the three-dimensional excitation K space of the test object includes: The radio frequency pulse is generated according to the three-dimensional map, the system matrix, the expected excitation shape and a weight matrix; the weight matrix is ​​determined according to the outline of the test object in the three-dimensional map and the expected excitation shape.

5. The method for generating parallel emission local excitation pulses according to claim 2, wherein: The smoothing process on the three-dimensional map to obtain an updated three-dimensional map includes: The amplitude and phase of the three-dimensional map are smoothed to obtain an updated three-dimensional map.

6. The method for generating parallel emission local excitation pulses according to claim 1, wherein: The radio frequency pulse includes amplitude and phase; The calculating the excitation uniformity according to the three-dimensional mapping image, the three-dimensional excitation K space and the radio frequency pulse includes: The excitation uniformity is calculated according to the three-dimensional mapping image, the three-dimensional excitation K space, the amplitude of the radio frequency pulse, and the phase of the radio frequency pulse.

7. A parallel emission local excitation pulse generating device, characterized in that: The device comprises: A generation module, configured to generate radio frequency pulses based on a three-dimensional map of the test object and a three-dimensional excitation K-space; a calculation module, configured to calculate excitation uniformity based on the three-dimensional mapping image, the three-dimensional excitation K space, and the radio frequency pulse; a first execution module, configured to update the three-dimensional mapping diagram and the three-dimensional excitation K space used for generating the radio frequency pulse and for calculating the excitation uniformity when the excitation uniformity is less than a preset value; wherein updating the three-dimensional mapping diagram and the three-dimensional excitation K space used for generating the radio frequency pulse and for calculating the excitation uniformity includes: reducing the sparsity of the three-dimensional excitation K space to obtain an updated three-dimensional excitation K space; The second execution module is configured to generate the parallel transmission local excitation pulses according to the three-dimensional excitation K space and the radio frequency pulse currently used to calculate the excitation uniformity when the excitation uniformity is greater than or equal to a preset value.

8. An electronic device comprising a memory and a processor, characterized in that: A computer program is stored in the memory, and the processor is configured to run the computer program to execute the parallel emission local excitation pulse generation method according to any one of claims 1 to 6.

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 parallel emission local excitation pulse generation method according to any one of claims 1 to 6 are implemented.

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