Magnetic resonance imaging sequence trajectory rewinding compensation method and device, medium and product

Abstract

The invention discloses a magnetic resonance imaging sequence trajectory rewinding compensation method and device, a medium and a product, and relates to the technical field of magnetic resonance imaging, and the method comprises the steps: collecting the actual gradient waveforms of three gradient axes in a set time period after an excitation radio frequency pulse is applied to a water model in a magnetic resonance scanner in the current repetition time; setting ideal gradient waveforms of three gradient axes in a set time period; any gradient axis is determined as a current axis; determining the residual gradient time moment of the current axis based on the actual gradient waveform and the ideal gradient waveform of the current axis in the set time period, and determining the waveform parameter of the current axis of the rewinding compensation gradient pulse; and applying a component of the rewinding compensation gradient pulse on the current axis to the current axis based on the residual gradient time moment of the current axis and the waveform parameter of the current axis of the rewinding compensation gradient pulse at the end moment of the phase disturbing gradient so as to realize the rewinding compensation of the magnetic resonance imaging sequence trajectory. According to the invention, the problems of quantitative deviation and image blurring of T2 weighted imaging are solved.

Description

Technical Field

[0001] This application relates to the field of magnetic resonance imaging technology, and in particular to a method, apparatus, medium and product for magnetic resonance imaging sequence trajectory loop compensation. Background Technology

[0002] Magnetic Resonance Imaging (MRI), as a non-invasive imaging technique, has been widely used in medical diagnosis and scientific research. In recent years, with the development of high-field MRI and high-performance gradient systems, the demand for rapid and high-resolution imaging has been increasing, especially in novel sequences such as Magnetic Resonance Fingerprinting (MRF) and 3D Spiral Projection Imaging (3D-SPI), where the accuracy of the signal evolution curve is even more critical. However, in related techniques, due to issues such as waveform mismatch, eddy current effects, and incomplete trajectory wrapping in gradient systems, a certain amount of gradient momentum (i.e., residual gradient time moment) often remains at the end of each repetition time (TR). This residual momentum may fluctuate between different TRs, resulting in insufficient signal refocusing. For sequences dependent on signal focusing (such as MRF), this instability can lead to image blurring, artifact enhancement, and systematic deviations in quantitative parameters such as T2.

[0003] To reduce the impact of residual gradient time moments, some methods typically employ pre-emphasis based on gradient transfer functions or eddy current models, or pre-set fixed wrapping gradient pulses through numerical simulation during the sequence design phase to make the actual output more closely resemble the ideal trajectory. Other methods use the phase difference of MR signals to infer the actual k-space trajectory, or use external magnetic field probes for one-time or periodic offline calibration, and then correct the trajectory during the image reconstruction phase. These methods can reduce trajectory mismatch and eddy current effects to some extent, but they generally rely on static models or non-real-time calibration, making it difficult to adapt to the dynamic errors per TR caused by gradient coil temperature rise, system aging, load changes, etc., and only make corrections at the "pre-design" or "post-reconstruction" level. The limitations are: 1) It is impossible to measure and dynamically compensate for the residual gradient moment at the end of each TR in real time; 2) Under conditions of high field, high gradient ascent rate and complex three-dimensional trajectory, model error and nonlinear effect will be significantly amplified, and fixed compensation scheme is difficult to remain effective in the long term; 3) Most methods only correct the trajectory at the reconstruction end, but do not actually compress the equivalent gradient momentum to near zero during the acquisition process. The insufficient refocusing of the spin during the evolution process cannot be completely recovered. Therefore, the systematic deviation correction of quantitative parameters such as T2 is still insufficient. Summary of the Invention

[0004] The purpose of this application is to provide a magnetic resonance imaging sequence trajectory loop compensation method, device, medium and product to reduce residual gradient time moment error without increasing additional scanning time, suppress T2 quantitative deviation and image blurring caused by insufficient signal refocusing from the source, improve quantitative accuracy and imaging robustness under high field, high gradient and complex sequence conditions, and effectively solve the problems of quantitative deviation and image blurring.

[0005] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides a method for compensating for trajectory reversal in magnetic resonance imaging (MRI) sequences. This method is performed during each repetition time interval of the MRI sequence executed by the MRI scanning system. The method includes: During the current repetition time, after applying an excitation radio frequency pulse to the water phantom set in the magnetic resonance scanner, the actual gradient waveform is acquired, and the actual gradient waveforms of the three gradient axes of the set time period within the current repetition time are obtained; the set time period is the time period with the acquisition start time as the initial time and the perturbation gradient end time as the end time; the three gradient axes are the orthogonal x-axis, y-axis and z-axis of the magnetic resonance imaging sequence; The ideal gradient waveforms of the three gradient axes are set for a given time period within the current repetition time. Define any gradient axis as the current axis; Based on the actual and ideal gradient waveforms of the current axis within a set time period, determine the residual gradient moment of the current axis. Based on the residual gradient moment of the current axis, the waveform parameters of the current axis for the wraparound compensation gradient pulse are determined; the waveform parameters include the maximum value and the switching rate. At the end of the perturbation gradient, based on the residual gradient moment of the current axis and the waveform parameters of the current axis of the wraparound compensation gradient pulse, the component of the wraparound compensation gradient pulse on the current axis is applied to the current axis to realize the wraparound compensation of the magnetic resonance imaging sequence trajectory.

[0006] In one embodiment, determining the residual gradient moment of the current axis based on the actual gradient waveform and the ideal gradient waveform of the current axis over a set time period includes: Based on the actual gradient waveform of the current axis during the set time period, determine the actual gradient field strength of the current axis at each moment during the set time period. Based on the ideal gradient waveform of the current axis during the set time period, determine the ideal gradient field strength of the current axis at each moment during the set time period. The residual gradient moment of the current axis is determined based on the actual gradient field strength and ideal gradient field strength of the current axis at each moment in the set time period.

[0007] In one embodiment, determining the residual gradient moment of the current axis based on the actual gradient field strength and the ideal gradient field strength of the current axis at each moment within a set time period includes: Using the residual gradient time moment calculation formula, the residual gradient time moment of the current axis is calculated based on the actual and ideal gradient field strengths of the current axis at each moment within a set time period. The residual gradient time moment calculation formula is as follows: ; in, Let be the residual gradient moment along the i-th gradient axis, in μs·mT / m. The end time of the perturbation gradient, in μs; Let be the actual gradient field strength of the i-th gradient axis at time t, in mT / m; Let be the ideal gradient field strength of the i-th gradient axis at time t, in mT / m.

[0008] In one embodiment, determining the waveform parameters of the current axis for the wraparound compensation gradient pulse based on the residual gradient moment of the current axis includes: Based on the residual gradient moment of the current axis, determine the maximum value of the current axis of the wraparound compensation gradient pulse; The switching rate of the current axis for the wraparound compensation gradient pulse is determined based on the maximum value of the wraparound compensation gradient pulse for the current axis.

[0009] In one embodiment, determining the maximum value of the current axis of the wraparound compensation gradient pulse based on the residual gradient moment of the current axis includes: Using the maximum value calculation formula, the maximum value of the wraparound compensation gradient pulse on the current axis is calculated based on the residual gradient moment on the current axis; the maximum value calculation formula is: ; in, The maximum value of the i-th gradient axis of the wraparound compensation gradient pulse, in mT / m; Let be the residual gradient moment along the i-th gradient axis, in μs·mT / m. The time for wrapping around the compensation gradient window is in μs.

[0010] In one embodiment, determining the switching rate of the current axis for the wraparound compensation gradient pulse based on the maximum value of the wraparound compensation gradient pulse for the current axis includes: Using the switching rate calculation formula, the switching rate of the current axis for the wraparound compensation gradient pulse is calculated based on the maximum value of the current axis's wraparound compensation gradient pulse; the switching rate calculation formula is: ; in, The switching rate of the i-th gradient axis of the wraparound compensation gradient pulse is expressed in mT / m / μs.

[0011] In one embodiment, when the component of the wraparound compensation gradient pulse on the current axis is applied to the current axis based on the residual gradient moment of the current axis and the waveform parameters of the current axis of the wraparound compensation gradient pulse, the direction of the component of the wraparound compensation gradient pulse on the current axis is opposite to the direction of the residual gradient moment of the current axis.

[0012] Secondly, this application provides a computer device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the magnetic resonance imaging sequence trajectory rewind compensation method described above.

[0013] Thirdly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the magnetic resonance imaging sequence trajectory wraparound compensation method described above.

[0014] Fourthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the magnetic resonance imaging sequence trajectory wraparound compensation method described above.

[0015] According to the specific embodiments provided in this application, the following technical effects are disclosed: This application discloses a method, apparatus, medium, and product for magnetic resonance imaging sequence trajectory wrap-around compensation. It can compensate the residual gradient time moment to zero in real time by applying a wrap-around compensation gradient pulse at the end of each repetition time, achieving precise wrap-around of the k-space trajectory. This eliminates the additional signal attenuation caused by non-T2 relaxation, making the signal evolution curves of techniques such as magnetic resonance fingerprinting more realistic, thereby reducing the systematic error of parameter fitting and significantly improving the quantitative accuracy of T2 relaxation times. By correcting gradient systematic errors through the wrap-around compensation gradient pulse, the point spread function of the imaging system is improved, mitigating image blurring and detail loss caused by trajectory mismatch, which is particularly beneficial for high-resolution imaging. It effectively solves the image blurring problem. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic flowchart of a magnetic resonance imaging sequence trajectory retracement compensation method provided in an embodiment of this application; Figure 2 This is a timing diagram of the trajectory wraparound compensation sequence; Figure 3 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] The purpose of this application is to provide a method, device, medium, and product for magnetic resonance imaging sequence trajectory loop compensation, which aims to reduce residual gradient time moment error without increasing additional scanning time, suppress T2 quantitative deviation and image blurring caused by insufficient signal refocusing from the source, improve quantitative accuracy and imaging robustness under high field, high gradient, and complex sequence conditions, and effectively solve the problems of quantitative deviation and image blurring.

[0020] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, this application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] In one exemplary embodiment, such as Figure 1 As shown, a magnetic resonance imaging sequence trajectory wrap-around compensation method is provided. The magnetic resonance imaging sequence trajectory wrap-around compensation method is executed in each repetition time of the magnetic resonance imaging sequence executed by the magnetic resonance scanning system. The magnetic resonance imaging sequence trajectory wrap-around compensation method includes the following steps.

[0022] Step 1: During the current repetition time, after applying an excitation radio frequency pulse to the water model set in the magnetic resonance scanner, start acquiring the actual gradient waveform to obtain the actual gradient waveform of the three gradient axes during the set time period within the current repetition time.

[0023] The time period is defined as the period from the start of acquisition to the end of the perturbation gradient; the three gradient axes are the orthogonal x-axis, y-axis and z-axis of the magnetic resonance imaging sequence.

[0024] Specifically, such as Figure 2As shown, a trigger signal from an external magnetic field probe is applied 200 μs before the spiral gradient waveform opens, to activate the external magnetic field measurement device (a Skope magnetic field camera is used in this example). A uniform, regularly shaped water phantom (usually a spherical or cylindrical container filled with pure water or other solutions) is placed in the magnetic resonance scanner to be calibrated for the gradient system. At each repetition time, an excitation radio frequency pulse is first applied to excite the water phantom signal. In this example, a Shinnar–Le Roux (SLR) excitation pulse is used.

[0025] Step 2: Set the ideal gradient waveform for the three gradient axes of the set time period within the current repetition time.

[0026] Step 3: Determine any gradient axis as the current axis.

[0027] Step 4: Determine the residual gradient moment of the current axis based on the actual gradient waveform and the ideal gradient waveform of the current axis within a set time period.

[0028] As an optional implementation, step 4 includes: Step 41: Determine the actual gradient field strength of the current axis at each moment within the set time period based on the actual gradient waveform of the current axis during the set time period; Step 42: Based on the ideal gradient waveform of the current axis during the set time period, determine the ideal gradient field strength of the current axis at each moment during the set time period; Step 43: Determine the residual gradient moment of the current axis based on the actual gradient field strength and ideal gradient field strength of the current axis at each moment in the set time period.

[0029] As an optional implementation, step 43 includes: Using the residual gradient time moment calculation formula, the residual gradient time moment of the current axis is calculated based on the actual and ideal gradient field strengths of the current axis at each moment within a set time period. The residual gradient time moment calculation formula is as follows: ; in, Let be the residual gradient moment along the i-th gradient axis, in μs·mT / m. The end time of the perturbation gradient, in μs; Let be the actual gradient field strength of the i-th gradient axis at time t, in mT / m; Let be the ideal gradient field strength of the i-th gradient axis at time t, in mT / m.

[0030] Step 5: Based on the residual gradient moment of the current axis, determine the waveform parameters of the current axis of the wraparound compensation gradient pulse.

[0031] The waveform parameters include the maximum value and the switching rate.

[0032] As an optional implementation, step 5 includes the following steps.

[0033] Step 51: Determine the maximum value of the current axis of the wraparound compensation gradient pulse based on the residual gradient moment of the current axis.

[0034] As an optional implementation, step 51 includes: Using the maximum value calculation formula, the maximum value of the wraparound compensation gradient pulse on the current axis is calculated based on the residual gradient moment on the current axis; the maximum value calculation formula is: ; in, The maximum value of the i-th gradient axis of the wraparound compensation gradient pulse, in mT / m; Let be the residual gradient moment along the i-th gradient axis, in μs·mT / m. The time for wrapping around the compensation gradient window is in μs.

[0035] Step 52: Based on the maximum value of the wraparound compensation gradient pulse of the current axis, determine the switching rate of the current axis of the wraparound compensation gradient pulse.

[0036] As an optional implementation, step 52 includes: Using the switching rate calculation formula, the switching rate of the current axis for the wraparound compensation gradient pulse is calculated based on the maximum value of the current axis's wraparound compensation gradient pulse; the switching rate calculation formula is: ; in, The switching rate of the i-th gradient axis of the wraparound compensation gradient pulse is expressed in mT / m / μs.

[0037] Specifically, based on the residual gradient time moments of each TR This generates a wraparound compensation gradient pulse. The core design principle of the wraparound compensation gradient pulse is to ensure that the generated time moment is equal in magnitude and opposite in direction to the residual time moment gradient. An equivalent requirement is that the area of ​​the wraparound compensation gradient pulse on that axis is equal to... This cancels out the combined effect. Considering that the residual gradient moment generally does not exceed 10 μs·mT / m in magnetic resonance scanners, and does not exceed 50 μs·mT / m in ultra-high gradient performance magnetic resonance scanners, in this example, the wraparound compensation gradient pulse uses a triangular waveform gradient (such as...). Figure 2 (As shown by the red triangle), its wraparound compensation gradient window time is... (This embodiment) Take 100 μs).

[0038] Step 6: At the end of the perturbation gradient, based on the residual gradient moment of the current axis and the waveform parameters of the current axis of the wraparound compensation gradient pulse, apply the component of the wraparound compensation gradient pulse on the current axis to the current axis to realize the wraparound compensation of the magnetic resonance imaging sequence trajectory.

[0039] As an optional implementation, in step 6, when applying the component of the wraparound compensation gradient pulse on the current axis based on the residual gradient moment of the current axis and the waveform parameters of the current axis of the wraparound compensation gradient pulse, the direction of the component of the wraparound compensation gradient pulse on the current axis is opposite to the direction of the residual gradient moment of the current axis.

[0040] Specifically, within each TR, after all spiral acquisition gradients within this TR have been completed and the phase-perturbation gradients used for phase baseline fine-tuning have been finished (see... Figure 2 The gradient amplifier in the magnetic resonance imaging device is controlled to apply peak values ​​in parallel along each gradient axis. Switching rate The direction and residual gradient time moment The opposite is the wraparound compensation gradient pulse. The purpose is to actively correct gradient system errors, accurately wrap the k-space trajectory back to zero, and ensure that the excitation echo signal can be perfectly converged, thereby eliminating the T2 quantitative deviation caused by incomplete convergence of the excitation echo.

[0041] In one exemplary embodiment, a computer device is provided, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement a magnetic resonance imaging sequence trajectory rewind compensation method.

[0042] In one exemplary embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements a magnetic resonance imaging sequence trajectory wraparound compensation method.

[0043] In one exemplary embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements a magnetic resonance imaging sequence trajectory wraparound compensation method.

[0044] In one exemplary embodiment, a computer device is provided, which may be a server or a terminal, and its internal structure diagram may be as follows. Figure 3As shown, this computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and databases. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a magnetic resonance imaging sequence trajectory cyclic compensation method.

[0045] Those skilled in the art will understand that Figure 3 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0046] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0047] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0048] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0049] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0050] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A magnetic resonance imaging sequence trajectory wraparound compensation method, the magnetic resonance imaging sequence trajectory wraparound compensation method being performed in each repetition time of a magnetic resonance imaging sequence performed by a magnetic resonance scanning system, characterized in that, The magnetic resonance imaging sequence trajectory wraparound compensation method comprises: In the current repetition time, after applying an excitation radio frequency pulse to a water phantom arranged in a magnetic resonance scanner, the actual gradient waveform is collected to obtain the actual gradient waveform of three gradient axes in a set period in the current repetition time; the set period is a period with the collection start time as the initial time and the phase-encoding gradient end time as the end time; the three gradient axes are the orthogonal x-axis, y-axis and z-axis of the magnetic resonance imaging sequence; The ideal gradient waveform of the three gradient axes in the set period in the current repetition time is set; Any gradient axis is determined as the current axis; Based on the actual gradient waveform and the ideal gradient waveform of the current axis in the set period, the residual gradient moment of the current axis is determined; Based on the residual gradient moment of the current axis, the waveform parameter of the current axis of the wraparound compensation gradient pulse is determined; the waveform parameter comprises a maximum value and a switching rate; At the phase-encoding gradient end time, based on the residual gradient moment of the current axis and the waveform parameter of the current axis of the wraparound compensation gradient pulse, the component of the wraparound compensation gradient pulse in the current axis is applied to the current axis to realize the magnetic resonance imaging sequence trajectory wraparound compensation.

2. The magnetic resonance imaging sequence trajectory wraparound compensation method of claim 1, wherein, Based on the actual gradient waveform and the ideal gradient waveform of the current axis in the set period, the residual gradient moment of the current axis is determined, comprising: According to the actual gradient waveform of the current axis in the set period, the actual gradient field strength of the current axis at each time in the set period is determined; According to the ideal gradient waveform of the current axis in the set period, the ideal gradient field strength of the current axis at each time in the set period is determined; According to the actual gradient field strength and the ideal gradient field strength of the current axis at each time in the set period, the residual gradient moment of the current axis is determined.

3. The magnetic resonance imaging sequence trajectory wraparound compensation method of claim 2, wherein, According to the actual gradient field strength and the ideal gradient field strength of the current axis at each time in the set period, the residual gradient moment of the current axis is determined, comprising: According to the actual gradient field strength and the ideal gradient field strength of the current axis at each time in the set period, the residual gradient moment of the current axis is calculated by using a residual gradient moment calculation formula; the residual gradient moment calculation formula is: ； wherein, is the residual gradient moment of the i-th gradient axis at time t, in units of μs·mT / m; is the end time of the spoiler gradient, in units of μs; is the actual gradient field strength of the i-th gradient axis at time t, in units of mT / m; is the ideal gradient field strength of the i-th gradient axis at time t, in units of mT / m.

4. The magnetic resonance imaging sequence trajectory wraparound compensation method of claim 1, wherein, Based on the residual gradient moment of the current axis, the waveform parameter of the current axis of the wraparound compensation gradient pulse is determined, comprising: Based on the residual gradient moment of the current axis, the maximum value of the current axis of the wraparound compensation gradient pulse is determined; Based on the maximum value of the current axis of the wraparound compensation gradient pulse, the switching rate of the current axis of the wraparound compensation gradient pulse is determined.

5. The magnetic resonance imaging sequence trajectory wraparound compensation method of claim 4, wherein, Based on the residual gradient moment of the current axis, the maximum value of the current axis of the wraparound compensation gradient pulse is determined, comprising: According to the residual gradient moment of the current axis, the maximum value of the current axis of the wraparound compensation gradient pulse is calculated by using a maximum value calculation formula; the maximum value calculation formula is: ； wherein, is the maximum value of the i-th gradient axis of the rewind compensation gradient pulse in mT / m; is the residual gradient moment of the i-th gradient axis in μs·mT / m; is the rewind compensation gradient window time in μs.

6. The magnetic resonance imaging sequence trajectory wraparound compensation method of claim 5, wherein, Based on the maximum value of the current axis of the wraparound compensation gradient pulse, the switching rate of the current axis of the wraparound compensation gradient pulse is determined, comprising: According to the maximum value of the current axis of the wraparound compensation gradient pulse, the switching rate of the current axis of the wraparound compensation gradient pulse is calculated by using a switching rate calculation formula; the switching rate calculation formula is: ； wherein, is the slew rate of the i-th gradient axis for the rewound gradient pulse, in mT / m / μs.

7. The magnetic resonance imaging sequence trajectory wraparound compensation method of claim 1, wherein, When applying the dephasing gradient pulse in the current axis, the direction of the dephasing gradient pulse in the current axis is opposite to the direction of the residual gradient time moment of the current axis.

8. A computer apparatus comprising: A memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that the processor executes the computer program to implement the magnetic resonance imaging sequence trajectory dephasing compensation method of any one of claims 1-7.

9. A computer readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the magnetic resonance imaging sequence trajectory dephasing compensation method of any one of claims 1-7.

10. A computer program product comprising a computer program, characterized in that, The computer program is executed by the processor to implement the magnetic resonance imaging sequence trajectory dephasing compensation method of any one of claims 1-7. The computer program is executed by the processor to implement the magnetic resonance imaging sequence trajectory dephasing compensation method of any one of claims 1-7.

Images