Readout gradient waveform determination method, magnetic resonance imaging system and storage medium

Abstract

The invention relates to a readout gradient waveform determination method, a magnetic resonance imaging system and a storage medium, and the method comprises the steps: executing a pulse sequence, and collecting an echo signal; the pulse sequence comprises a radio frequency pulse, a preamble gradient and a readout gradient, and the target moment of the preamble gradient of the next pulse sequence period of the pulse sequence is greater than the target moment of the preamble gradient of the current pulse sequence period of the pulse sequence; acquiring a target value and a target moment of the echo signal; the target value is the maximum value of the amplitude of the echo signal of each pulse sequence period, and the target moment is the moment corresponding to the target value; and determining the readout gradient waveform according to the target value and the target moment. According to the method, the actual waveform of the readout gradient is determined according to the maximum value of the echo signal of each period and the corresponding moment, and the problem that a calculation mode of the actual readout gradient waveform cannot be provided in the prior art is solved.

Description

Technical Field

[0001] The present application relates to the technical field of magnetic resonance imaging, and in particular to a method for determining a readout gradient waveform, a magnetic resonance imaging system and a storage medium. Background Art

[0002] Nuclear magnetic resonance uses an external magnetic field to make the protons in the object under test produce a macroscopic magnetization vector, and then uses radio frequency pulses for excitation to make the macroscopic magnetization vector precess around the direction of the magnetic field, thereby generating a magnetic resonance signal. After the magnetic resonance signal is acquired, a tissue image of the object under test, i.e., a magnetic resonance image, can be obtained by reconstruction. The gradient field is one of the three major fields that affect the quality of magnetic resonance imaging. Usually, there is a deviation between the actual readout gradient waveform and the ideal readout gradient waveform, which makes the magnetic resonance image obtained by image reconstruction using the ideal readout gradient waveform have errors. Therefore, it is necessary to obtain an accurate actual readout gradient waveform to provide a correction basis for image reconstruction.

[0003] The prior art fails to provide a practical method for calculating the readout gradient waveform. Summary of the invention

[0004] The present application provides a method for determining a readout gradient waveform, a magnetic resonance imaging system and a storage medium to solve the problem that the prior art fails to provide an actual method for calculating the readout gradient waveform.

[0005] In a first aspect, a method for determining a readout gradient waveform is provided in the present application, the method comprising:

[0006] Executing a pulse sequence to collect echo signals; the pulse sequence includes a radio frequency pulse, a pre-gradient and a readout gradient, wherein a target moment of the pre-gradient of a next pulse sequence cycle of the pulse sequence is greater than a target moment of the pre-gradient of a current pulse sequence cycle of the pulse sequence;

[0007] Acquire a target value and a target time of the echo signal; the target value is the maximum value of the amplitude of the echo signal in each pulse sequence period, and the target time is the time corresponding to the target value;

[0008] The readout gradient waveform is determined according to the target value and the target time.

[0009] In some embodiments, determining the readout gradient waveform according to the target value and the target time comprises:

[0010] The readout gradient waveform is determined according to the target values ​​of two adjacent pulse sequence cycles and the corresponding target time.

[0011] In some embodiments, determining the readout gradient waveform according to the target values ​​and corresponding target times of two adjacent pulse sequence cycles includes:

[0012] Obtaining a first difference value; the first difference value is the difference between a target value of a next pulse sequence cycle and a target value of a current pulse sequence cycle;

[0013] Acquire a second difference, where the second difference is a difference between a target time of a next pulse sequence cycle and a target time of a current pulse sequence cycle;

[0014] The readout gradient waveform is determined according to the first difference and the second difference.

[0015] In some embodiments, determining the readout gradient waveform according to the first difference and the second difference includes:

[0016] determining an amplitude of the readout gradient waveform according to the first difference and the second difference;

[0017] Determining the time corresponding to the amplitude of the gradient waveform according to the target time of the next pulse sequence cycle and the target time of the current pulse sequence cycle;

[0018] The readout gradient waveform is determined according to the amplitude of the readout gradient waveform and the time corresponding to the amplitude of the gradient waveform.

[0019] In some embodiments, the amplitude of the readout gradient waveform is the quotient of the first difference and the second difference, and the moment corresponding to the amplitude of the gradient waveform is the middle moment between the target moment of the next pulse sequence cycle and the target moment of the current pulse sequence cycle.

[0020] In some of the embodiments, the target moment of the preceding gradient is the zero-order moment of the preceding gradient.

[0021] In some of the embodiments, the target moment of the pre-gradient is an integral value of the amplitude of the pre-gradient over a duration.

[0022] In some of the embodiments, a phase of a pre-gradient waveform of the pre-gradient is opposite to a phase of a readout gradient waveform of the readout gradient.

[0023] In a second aspect, the present application provides a magnetic resonance imaging system, comprising a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute the method for determining the readout gradient waveform described in the first aspect.

[0024] In a third aspect, a device for determining a readout gradient waveform is provided in the present application, the device comprising:

[0025] An acquisition module, used for executing a pulse sequence and acquiring echo signals; the pulse sequence includes a radio frequency pulse, a pre-gradient and a readout gradient, wherein a target moment of the pre-gradient of a next pulse sequence cycle of the pulse sequence is greater than a target moment of the pre-gradient of a current pulse sequence cycle of the pulse sequence;

[0026] An acquisition module, used for acquiring a target value and a target time of the echo signal; the target value is the maximum value of the amplitude of the echo signal in each pulse sequence period, and the target time is the time corresponding to the target value;

[0027] A determination module is used to determine the readout gradient waveform according to the target value and the target time.

[0028] In a fourth aspect, the present application provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute the method for determining the readout gradient waveform described in the first aspect.

[0029] In a fifth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the method for determining the readout gradient waveform described in the first aspect are implemented.

[0030] Compared with the prior art, the present application provides a method for determining a readout gradient waveform, a magnetic resonance imaging system, and a storage medium, which set different pre-gradients according to each pulse sequence cycle, so that the time of the maximum value of the echo signal in each cycle is different, and the actual waveform of the readout gradient is determined according to the maximum value of the echo signal in each cycle and the corresponding time, thereby solving the problem that the prior art fails to provide a calculation method for the actual readout gradient waveform.

[0031] Details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0033] Figure 1 It is a hardware structure block diagram of a terminal for executing a method for determining a readout gradient waveform according to an embodiment of the present application;

[0034] Figure 2 is a flow chart of a method for determining a readout gradient waveform according to an embodiment of the present application;

[0035] Figure 3 is a structural schematic diagram of a magnetic resonance imaging system according to an embodiment of the present application;

[0036] Figure 4 is a flow chart of another method for determining a readout gradient waveform according to an embodiment of the present application;

[0037] Figure 5 is a schematic diagram of a pulse sequence of an embodiment of the present application;

[0038] Figure 6 It is a structural block diagram of a device for determining a readout gradient waveform according to an embodiment of the present application. DETAILED DESCRIPTION

[0039] 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.

[0040] Unless otherwise defined, the technical terms or scientific terms involved in this application shall have the general meaning understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the", "these" and the like in this application do not represent 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 directly or indirectly. The "multiple" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone. Usually, the character " / " indicates that the objects associated with each other are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0041] The method embodiments provided in this application can be executed in a terminal, a computer or a similar computing device. For example, running on a terminal, Figure 11 is a hardware structure block diagram of a terminal for executing a method for determining a readout gradient waveform according to an embodiment of the present application. Figure 1 As shown, the terminal may include one or more ( Figure 1 Only one is shown in the figure) processor 102 and memory 104 for storing data, wherein processor 102 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA. The above terminal may also include a transmission device 106 and an input and output device 108 for communication functions. It can be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the above terminal. Figure 1 More or fewer components as shown, or with Figure 1 Different configurations shown.

[0042] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as a computer program corresponding to a method for determining a readout gradient waveform in the present embodiment. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, to implement the above method. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories may be connected to the terminal via a network. Examples of the above network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0043] The transmission device 106 is used to receive or send data via a network. The above network includes a wireless network provided by the communication provider of the terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, referred to as NIC), 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, referred to as RF) module, which is used to communicate with the Internet wirelessly.

[0044] The present application provides a method for determining a readout gradient waveform. Figure 2 1 is a flow chart of a method for determining a readout gradient waveform according to an embodiment of the present application. The method for determining a readout gradient waveform is applied to a magnetic resonance imaging system. The magnetic resonance imaging system includes a processor, a memory, and a scanner. The method is applied to a processor in a magnetic resonance imaging system as an example for explanation. Figure 2 As shown, the process includes the following steps:

[0045] Step S210, executing a pulse sequence to collect echo signals; the pulse sequence includes a radio frequency pulse, a pre-gradient and a readout gradient, wherein a target moment of a pre-gradient of a next pulse sequence cycle of the pulse sequence is greater than a target moment of a pre-gradient of a current pulse sequence cycle of the pulse sequence.

[0046] Specifically, after the processor executes the pulse sequence, the echo signal is collected within the readout gradient, and the pulse sequence includes a radio frequency pulse, a readout gradient, and a pre-gradient applied before the readout gradient. The pulse sequence includes a plurality of pulse sequence cycles, each pulse sequence cycle of the pulse sequence includes a radio frequency pulse, a readout gradient, and a pre-gradient applied before the readout gradient, and the target moment of the pre-gradient of the next pulse sequence cycle of the pulse sequence is greater than the target moment of the pre-gradient of the current pulse sequence cycle of the pulse sequence. The target moment here may be an M-order moment, where M is an integer greater than or equal to zero. Taking the target moment as a zero-order moment as an example, the zero-order moment of the pre-gradient may be the integral value of the amplitude of the pre-gradient signal within the duration of the pre-gradient signal.

[0047] The pulse sequence in the present application may also be referred to as a scanning sequence, which refers to a combination mode and timing relationship of a group of periodically repeated radio frequency pulses required to generate and measure magnetic resonance signals. For example, the pulse sequence may be a periodic arrangement of the settings of relevant parameters such as radio frequency pulses, gradient fields, and signal acquisition time in a timing sequence. The parameters related to radio frequency pulses may include bandwidth (frequency band range), amplitude, application time, and duration, etc.; the parameters of the gradient field may include the application direction of the gradient field, the field strength of the gradient field, the gradient time, and the dimension time, etc., which are not specifically limited here.

[0048] In some of the embodiments, the pulse sequence in the present application may include five parts, namely, radio frequency pulse, slice selection gradient field, phase encoding gradient field, frequency encoding gradient field and MR signal acquisition window. In addition, the pulse sequence in the embodiments of the present application may be a combination of one or more of a free induction decay (FID) sequence, a spin echo (Fast SpinEcho) sequence, a gradient echo (GRE) sequence, a hybrid sequence, etc., which is not specifically limited here.

[0049] Step S220, obtaining a target value and a target time of the echo signal; the target value is the maximum value of the amplitude of the echo signal in each pulse sequence period, and the target time is the time corresponding to the target value.

[0050] Specifically, the processor obtains the target value and target time of the echo signal according to the collected echo signal, where the target value is the maximum value of the amplitude of the echo signal in each pulse sequence period, and the target time is the time corresponding to the target value. The processor analyzes the collected echo signal to obtain the maximum value of the amplitude of the echo signal collected in each pulse sequence period and the time corresponding to the maximum value of the amplitude of the echo signal.

[0051] Step S230, determining the readout gradient waveform according to the target value and the target time.

[0052] Specifically, the processor determines the actual waveform of the readout gradient of each pulse sequence period according to the maximum value of the amplitude of the echo signal collected in each pulse sequence period and the time corresponding to the maximum value of the amplitude of the echo signal.

[0053] Through the above steps, different pre-gradients are set according to each pulse sequence period, so that the time of the maximum value of the echo signal in each period is different. The actual waveform of the readout gradient is determined according to the maximum value of the echo signal in each period and the corresponding time, which solves the problem that the prior art fails to provide a calculation method for the actual readout gradient waveform.

[0054] In some of the embodiments, determining the readout gradient waveform according to the target value and the target time includes: determining the readout gradient waveform according to the target values ​​and the corresponding target time of two adjacent pulse sequence cycles.

[0055] Specifically, the processor determines the amplitude and corresponding time of the readout gradient waveform according to the target values ​​and corresponding target time of two adjacent pulse sequence cycles, and determines the actual waveform of the readout gradient according to the determined amplitude and corresponding time of the gradient waveform.

[0056] In some of the embodiments, the readout gradient waveform is determined based on the target values ​​and corresponding target moments of two adjacent pulse sequence cycles, including: obtaining a first difference; the first difference is the difference between the target value of the next pulse sequence cycle and the target value of the current pulse sequence cycle; obtaining a second difference, the second difference is the difference between the target moment of the next pulse sequence cycle and the target moment of the current pulse sequence cycle; and determining the readout gradient waveform based on the first difference and the second difference.

[0057] Specifically, the processor first obtains the difference between the target value of the next pulse sequence cycle and the target value of the current pulse sequence cycle, and obtains the difference between the target moment of the next pulse sequence cycle and the target moment of the current pulse sequence cycle; the processor determines the amplitude of the readout gradient waveform according to the difference between the target value of the next pulse sequence cycle and the target value of the current pulse sequence cycle and the difference between the target moment of the next pulse sequence cycle and the target moment of the current pulse sequence cycle; the processor determines the time corresponding to the amplitude of the gradient waveform according to the target moment of the next pulse sequence cycle and the target moment of the current pulse sequence cycle; the processor determines the readout gradient waveform, that is, the actual waveform of the readout gradient, according to the determined amplitude of the readout gradient waveform and the time corresponding to the amplitude of the readout gradient waveform.

[0058] In some embodiments, the amplitude of the read gradient waveform is the quotient of the first difference and the second difference, and the moment corresponding to the amplitude of the gradient waveform is the middle moment between the target moment of the next pulse sequence cycle and the target moment of the current pulse sequence cycle.

[0059] Specifically, the processor calculates the quotient of the difference between the target value of the next pulse sequence cycle and the target value of the current pulse sequence cycle and the difference between the target moment of the next pulse sequence cycle and the target moment of the current pulse sequence cycle as the amplitude of the read-out gradient waveform, and the processor determines the middle moment between the target moment of the next pulse sequence cycle and the target moment of the current pulse sequence cycle as the moment corresponding to the amplitude of the gradient waveform.

[0060] In some of the embodiments, the phase of the pre-gradient waveform of the pre-gradient is opposite to the phase of the readout gradient waveform of the readout gradient.

[0061] The present application provides a magnetic resonance imaging system, which includes a memory and a processor. The memory stores a computer program, and the processor is configured to run the computer program to execute the method for determining a readout gradient waveform in an embodiment of the present application.

[0062] The processor of the magnetic resonance imaging system in this embodiment sets different pre-gradients according to each pulse sequence cycle, so that the time of the maximum value of the echo signal in each cycle is different. The actual waveform of the readout gradient is determined according to the maximum value of the echo signal in each cycle and the corresponding time, which solves the problem that the prior art fails to provide a calculation method for the actual readout gradient waveform.

[0063] The present application also provides a magnetic resonance imaging system, Figure 3 is a schematic diagram of the structure of a magnetic resonance imaging system according to an embodiment of the present application. Figure 3As shown, the magnetic resonance imaging system includes a first processor 310, a first memory 320 and a scanner 330. The first memory 320 stores a computer program. The first processor 310 is configured to run the computer program to execute the method for determining the readout gradient waveform in the embodiment of the present application. The first processor 310 controls the scanner 330 to transmit a target pulse waveform for magnetic resonance scanning.

[0064] After receiving the scanning instruction, the magnetic resonance imaging system obtains the pulse sequence corresponding to the scanning instruction, and controls the scanner 330 to transmit the target pulse waveform corresponding to the pulse sequence to perform magnetic resonance scanning according to the pulse sequence, so as to execute the pulse sequence. The scanner 330 in the magnetic resonance imaging system includes various coils, such as RF transmitting coils, RF receiving coils, etc., and gradient coils, etc. By driving these coils of the scanner 330, magnetic resonance signals can be received or corresponding pulses can be transmitted, that is, after the target pulse waveform is generated, the RF coils and gradient coils in the scanner 330 can be controlled to execute the corresponding target pulse waveform. Each pulse sequence has a corresponding pulse waveform, and the pulse waveform includes waveform content and waveform characterization data. The waveform content refers to the waveform of the pulse waveform itself, and the waveform characterization data refers to the data used to represent the pulse waveform. For example, the waveform characterization data of the radio frequency pulse waveform can be parameters related to the radio frequency pulse, including bandwidth (frequency band range), amplitude, application time and duration, etc.; the waveform characterization data of the gradient pulse waveform can be parameters of the gradient field, including the application direction of the gradient field, the field strength of the gradient field, the gradient time and size time, etc.

[0065] The first processor of the magnetic resonance imaging system in this embodiment sets different pre-gradients according to each pulse sequence cycle, so that the time of the maximum value of the echo signal in each cycle is different. The actual waveform of the readout gradient is determined according to the maximum value of the echo signal in each cycle and the corresponding time, which solves the problem that the prior art fails to provide a calculation method for the actual readout gradient waveform.

[0066] The present application also provides a method for determining a readout gradient waveform. Figure 4 is a flow chart of another method for determining a readout gradient waveform according to an embodiment of the present application. Figure 4 As shown, the process includes the following steps:

[0067] Step S410, acquiring an echo signal.

[0068] Specifically, the pulse sequence includes a radio frequency pulse, a pre-gradient and a readout gradient. The readout gradient is the gradient for obtaining the actual gradient waveform. The pre-gradient is applied before the readout gradient. The zero-order moment of the pre-gradient of N pulse sequence cycles is M i , i=1,2,…,N, where N is a positive integer, M1 <M2<…<MN That is, the zero-order moment of the pre-gradient of the next pulse sequence period is greater than the zero-order moment of the pre-gradient of the current pulse sequence period, and the phase of the pre-gradient waveform of the pre-gradient is opposite to the phase of the readout gradient waveform of the readout gradient. Data acquisition is performed separately for the readout gradients, and the corresponding gradient echo signals are denoted as S i , i = 1, 2, …, N, where N is a positive integer. N is the number of measurements, and the more the number of measurements, the higher the calculation accuracy of the gradient waveform. The gradient echo signal here is the echo signal in this application, and the zero-order moment of the pre-gradient can be the integral value of the amplitude of the pre-gradient signal within the duration of the pre-gradient signal.

[0069] As Figure 5 shown, taking two pulse sequence periods T1 and T2 of the pulse sequence as an example, the pulse sequence includes a radio frequency pulse, a pre-gradient, and a readout gradient. The integral value of the amplitude of the pre-gradient signal of period T1 within the duration of the pre-gradient signal is less than the integral value of the amplitude of the pre-gradient signal of period T2 within the duration of the pre-gradient signal, that is, M1 < M2. The interval between the start time of the readout gradient and the cut-off time of the radio frequency pulse is the same for each pulse sequence period. Data acquisition is performed for the readout gradient, that is, echo signal acquisition, to obtain the gradient echo signal. It should be noted that Figure 5 only gives a schematic description of two pulse sequence periods. It can be understood that the pulse sequence includes multiple pulse sequence periods, and the zero-order moment of the pre-gradient of the next pulse sequence period is greater than the zero-order moment of the pre-gradient of the current pulse sequence period, that is, M1 < M2 < … < M N .

[0070] Step S420, obtain the maximum value of the echo signal of each pulse sequence period and the echo time corresponding to the maximum value.

[0071] Respectively find the maximum value of the gradient echo signal of each pulse sequence period, and the moment corresponding to the maximum value of the gradient echo signal, that is, the echo time corresponding to the maximum value of the gradient echo signal, which are respectively denoted as t i , i = 1, 2, …, N.

[0072] Step S430, calculate the pre-gradient moment difference and the echo time difference.

[0073] Specifically, calculate the pre-gradient moment difference and the echo time difference of each pulse sequence period respectively. The pre-gradient moment difference is DM i = M i+1 - M i , i = 1, 2, …, N - 1, and the echo time difference is DT i = t i+1 - t i , i = 1, 2, …, N - 1.

[0074] Step S440, calculating the actual gradient amplitude and the time corresponding to the actual gradient amplitude.

[0075] Specifically, the actual gradient amplitude G is calculated respectively i =DM i / DT i , i = 1, 2, ..., N-1, and the time TM corresponding to the actual gradient amplitude i =(t i+1 +t i ) / 2, i=1,2,…,N-1, the actual gradient amplitude and its corresponding time determine the actual waveform of the readout gradient.

[0076] Through the above steps, different pre-gradients are set according to each pulse sequence period, so that the time of the maximum value of the echo signal in each period is different. The actual waveform of the readout gradient is determined according to the maximum value of the echo signal in each period and the corresponding time, which solves the problem that the prior art fails to provide a calculation method for the actual readout gradient waveform.

[0077] It should be noted that the steps shown in the above process or the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0078] In the present application, a determination device for reading out the gradient waveform is also provided, and the device is used to implement the above-mentioned embodiments and preferred embodiments, and the descriptions that have been made will not be repeated. The terms "module", "unit", "subunit" and the like used below can implement a combination of software and / or hardware of a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware is also possible and conceived.

[0079] Figure 6 is a structural block diagram of a device for determining a readout gradient waveform according to an embodiment of the present application. Figure 6 As shown, the device comprises:

[0080] An execution module 610 is used to execute a pulse sequence to collect echo signals; the pulse sequence includes a radio frequency pulse, a pre-gradient and a readout gradient, wherein a target moment of a pre-gradient of a next pulse sequence cycle of the pulse sequence is greater than a target moment of a pre-gradient of a current pulse sequence cycle of the pulse sequence;

[0081] An acquisition module 620 is used to acquire a target value and a target time of the echo signal; the target value is the maximum value of the amplitude of the echo signal in each pulse sequence period, and the target time is the time corresponding to the target value;

[0082] The determination module 630 is used to determine the readout gradient waveform according to the target value and the target time.

[0083] It should be noted that the above modules can be functional modules or program modules, and can be implemented by software or hardware. For modules implemented by hardware, the above modules can be located in the same processor; or the above modules can be located in different processors in any combination.

[0084] The present application also provides an electronic device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0085] Optionally, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor, and the input / output device is connected to the processor.

[0086] Optionally, in this embodiment, the processor may be configured to perform the following steps through a computer program:

[0087] S1, executing a pulse sequence to collect echo signals; the pulse sequence includes a radio frequency pulse, a pre-gradient and a readout gradient, wherein a target moment of a pre-gradient of a next pulse sequence cycle of the pulse sequence is greater than a target moment of a pre-gradient of a current pulse sequence cycle of the pulse sequence;

[0088] S2, obtaining a target value and a target time of the echo signal; the target value is the maximum value of the amplitude of the echo signal in each pulse sequence period, and the target time is the time corresponding to the target value;

[0089] S3, determining the readout gradient waveform according to the target value and the target time.

[0090] It should be noted that the specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementation modes, and will not be repeated in this embodiment.

[0091] In addition, in combination with a method for determining a readout gradient waveform provided in the above embodiment, a storage medium may be provided in this embodiment to implement the method. The storage medium stores a computer program; when the computer program is executed by a processor, the steps of any method for determining a readout gradient waveform in the above embodiment are implemented.

[0092] It should be understood that the specific embodiments described herein are only used to explain the application, rather than to limit it. Based on the embodiments provided in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of this application.

[0093] Obviously, the drawings are only some examples or embodiments of the present application. For ordinary technicians in the field, the present application can also be applied to other similar situations based on these drawings without creative work. In addition, it is understandable that although the work done in this development process may be complicated and lengthy, for ordinary technicians in the field, certain changes in design, manufacturing or production based on the technical content disclosed in this application are only conventional technical means and should not be regarded as insufficient content disclosed in this application.

[0094] The term "embodiment" in this application refers to a specific feature, structure or characteristic described in conjunction with the embodiment that can be included in at least one embodiment of the present application. The appearance of this phrase in various locations in the specification does not necessarily mean the same embodiment, nor does it mean that it is mutually exclusive with other embodiments and is independent or optional. It is clearly or implicitly understood by those of ordinary skill in the art that the embodiments described in this application can be combined with other embodiments without conflict.

[0095] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of patent protection. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the attached claims.

Claims

1. A method for determining a readout gradient waveform, characterized in that: The method comprises: Executing a pulse sequence to collect echo signals; the pulse sequence includes a radio frequency pulse, a pre-gradient and a readout gradient, wherein a target moment of the pre-gradient of a next pulse sequence cycle of the pulse sequence is greater than a target moment of the pre-gradient of a current pulse sequence cycle of the pulse sequence; Acquire a target value and a target time of the echo signal; the target value is the maximum value of the amplitude of the echo signal in each pulse sequence period, and the target time is the time corresponding to the target value; The readout gradient waveform is determined according to the target value and the target time.

2. The method for determining a readout gradient waveform according to claim 1, characterized in that: Determining the readout gradient waveform according to the target value and the target time includes: The readout gradient waveform is determined according to the target values ​​of two adjacent pulse sequence cycles and the corresponding target time.

3. The method for determining a readout gradient waveform according to claim 2, characterized in that: The step of determining the readout gradient waveform according to the target values ​​of two adjacent pulse sequence cycles and the corresponding target time comprises: Obtaining a first difference value; the first difference value is the difference between a target value of a next pulse sequence cycle and a target value of a current pulse sequence cycle; Acquire a second difference, where the second difference is a difference between a target time of a next pulse sequence cycle and a target time of a current pulse sequence cycle; The readout gradient waveform is determined according to the first difference and the second difference.

4. The method for determining a readout gradient waveform according to claim 3, characterized in that: The step of determining the readout gradient waveform according to the first difference and the second difference comprises: determining an amplitude of the readout gradient waveform according to the first difference and the second difference; Determining the time corresponding to the amplitude of the gradient waveform according to the target time of the next pulse sequence cycle and the target time of the current pulse sequence cycle; The readout gradient waveform is determined according to the amplitude of the readout gradient waveform and the time corresponding to the amplitude of the gradient waveform.

5. The method for determining a readout gradient waveform according to claim 4, characterized in that: The amplitude of the readout gradient waveform is the quotient of the first difference and the second difference, and the time corresponding to the amplitude of the gradient waveform is the middle time between the target time of the next pulse sequence cycle and the target time of the current pulse sequence cycle.

6. The method for determining a readout gradient waveform according to claim 1, characterized in that: The target moment of the preceding gradient is the zero-order moment of the preceding gradient.

7. The method for determining a readout gradient waveform according to claim 1, characterized in that: The target moment of the pre-gradient is the integral value of the amplitude of the pre-gradient within the duration.

8. The method for determining a readout gradient waveform according to any one of claims 1 to 7, characterized in that: A phase of a pre-gradient waveform of the pre-gradient is opposite to a phase of a readout gradient waveform of the readout gradient.

9. A magnetic resonance imaging system, 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 perform the method for determining a readout gradient waveform according to any one of claims 1 to 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the computer program implements the steps of the method for determining a readout gradient waveform according to any one of claims 1 to 8.

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