Magnetic field force adjustment method and device, computer device, medium and imaging system

Abstract

The application relates to a magnetic field force adjusting method and device, computer equipment, a medium and an imaging system. The method comprises the following steps: acquiring a magnetic field force impulse of an original gradient pulse in a magnetic resonance scanning sequence; determining a compensation gradient pulse with the same size and opposite direction as the magnetic field force impulse of the original gradient pulse based on the magnetic field force impulse of the original gradient pulse; and adjusting the magnetic field force of a magnetic resonance imaging environment by applying the original gradient pulse and the compensation gradient pulse to the magnetic resonance imaging environment. The method can apply the compensation gradient pulse to the magnetic resonance imaging environment on the basis of the original gradient pulse, so that the compensation gradient pulse and the original gradient pulse jointly act to weaken the magnetic field force of the magnetic resonance imaging environment on a ferromagnetic object. Even if the additional compensation gradient pulse is applied to the magnetic resonance imaging environment, the motion control of the ferromagnetic object is not affected, so that a better motion control effect is achieved, and the accuracy of the actual motion of the ferromagnetic object is greatly increased.

Description

Technical Field

[0001] This application relates to the field of medical technology, and in particular to a method, apparatus, computer equipment, medium, and imaging system for adjusting magnetic field force. Background Technology

[0002] Magnetic resonance imaging (MRI) technology has advantages such as high spatial resolution, superior soft tissue contrast, and no ionizing radiation, making it a very important imaging technology in the field of clinical medical auxiliary diagnosis.

[0003] In related technologies, ferromagnetic objects can be used to assist in the clinical application of magnetic resonance imaging. For example, the movement of ferromagnetic objects in a magnetic resonance environment can be used to perform minimally invasive surgery, targeted drug delivery, and other operations.

[0004] However, the gradient magnetic field introduced during magnetic resonance imaging in related technologies can disrupt the desired motion control of ferromagnetic objects. Summary of the Invention

[0005] Therefore, it is necessary to provide a magnetic field force adjustment method, device, computer equipment, medium, and imaging system to address the above-mentioned technical problems.

[0006] In a first aspect, embodiments of this application provide a method for adjusting magnetic field force, the method comprising:

[0007] Obtain the magnetic force impulse of the original gradient pulse in the magnetic resonance scanning sequence;

[0008] The compensated gradient pulse is determined based on the magnetic field impulse of the original gradient pulse; the magnetic field impulse of the original gradient pulse and the magnetic field impulse of the compensated gradient pulse are the same in magnitude and opposite in direction.

[0009] The magnetic field force of the magnetic resonance imaging environment is adjusted by applying the original gradient pulse and the compensated gradient pulse to the magnetic resonance imaging environment; wherein the adjusted magnetic field force exerts a smaller force on ferromagnetic objects moving in the magnetic resonance imaging environment than the preset force.

[0010] In one embodiment, determining the compensated gradient pulse based on the magnetic force impulse of the original gradient pulse includes:

[0011] Based on the magnetic force impulse of the original gradient pulse, the impulse gradient formed by the magnetic force impulse is divided to obtain at least two original gradient blocks.

[0012] Determine the compensation gradient block corresponding to each original gradient block;

[0013] The compensation gradient pulse is determined based on the compensation gradient block corresponding to each original gradient block.

[0014] In one embodiment, the impulse gradient formed by the magnetic force impulse is divided according to the magnetic force impulse of the original gradient pulse to obtain at least two original gradient blocks, including:

[0015] Obtain the equivalent center of the radio frequency pulse in the magnetic resonance scanning sequence;

[0016] Based on the equivalent center and the magnetic impulse of the original gradient pulse, the impulse gradient is divided to obtain at least two original gradient blocks.

[0017] In one embodiment, determining the compensation gradient block corresponding to each original gradient block includes:

[0018] For any original gradient block, obtain the area and direction of the original gradient block, and based on the area and direction of the original gradient block, determine the gradient block with the same area and opposite direction as the original gradient block as the compensation gradient block corresponding to the original gradient block.

[0019] In one embodiment, the original gradient pulse includes an original gradient pulse in the X direction, an original gradient pulse in the Y direction, and an original gradient pulse in the Z direction;

[0020] Determining the compensated gradient pulse based on the magnetic force impulse of the original gradient pulse includes:

[0021] Based on the magnetic impulse of the original gradient pulse in the target direction, the target direction compensation gradient pulse corresponding to the original gradient pulse in the target direction is determined; the original gradient pulse in the target direction is at least one of the original gradient pulse in the X direction, the original gradient pulse in the Y direction, and the original gradient pulse in the Z direction.

[0022] The compensation gradient pulse is determined based on the target direction compensation gradient pulse.

[0023] In one embodiment, the method further includes:

[0024] The radio frequency signal data generated by the imaging object in the magnetic resonance imaging environment under the excitation of the adjusted magnetic resonance scanning sequence is acquired; the adjusted magnetic resonance scanning sequence includes radio frequency pulses, original gradient pulses, and compensated gradient pulses.

[0025] Magnetic resonance images of the imaging object are generated based on radio frequency signal data.

[0026] Secondly, an embodiment of this application provides a magnetic field force adjustment device, the device comprising:

[0027] The magnetic field impulse acquisition module is used to acquire the magnetic field impulse of the original gradient pulse in the magnetic resonance scanning sequence.

[0028] The compensation pulse determination module is used to determine the compensation gradient pulse based on the magnetic field impulse of the original gradient pulse; the magnetic field impulse of the original gradient pulse and the magnetic field impulse of the compensation gradient pulse are the same in magnitude and opposite in direction.

[0029] The magnetic field force adjustment module is used to adjust the magnetic field force of the magnetic resonance imaging environment by applying original gradient pulses and compensated gradient pulses to the magnetic resonance imaging environment; wherein, the adjusted magnetic field force exerts a force on ferromagnetic objects moving in the magnetic resonance imaging environment less than the preset force.

[0030] Thirdly, an embodiment of this application provides a computer device including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of any of the methods in the first aspect embodiment described above.

[0031] Fourthly, embodiments of this application provide a readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of any of the methods described in the first aspect embodiments.

[0032] Fifthly, this application provides a magnetic resonance imaging system, which includes magnetic resonance imaging equipment and computer equipment;

[0033] The computer equipment is used to acquire the magnetic field impulse of the original gradient pulse in the magnetic resonance scanning sequence, and to determine the compensation gradient pulse based on the magnetic field impulse of the original gradient pulse; the magnetic field impulse of the original gradient pulse and the magnetic field impulse of the compensation gradient pulse are the same in magnitude and opposite in direction.

[0034] Magnetic resonance imaging equipment is used to adjust the magnetic field force of the magnetic resonance imaging environment by applying original gradient pulses and compensated gradient pulses to the magnetic resonance imaging environment; wherein, the adjusted magnetic field force exerts a force on ferromagnetic objects moving in the magnetic resonance imaging environment less than a preset force.

[0035] The magnetic field force adjustment method, apparatus, computer equipment, medium, and imaging system provided in this application embodiment can acquire the magnetic field force impulse of the original gradient pulse in the magnetic resonance scanning sequence. Based on the magnetic field force impulse of the original gradient pulse, a compensation gradient pulse with the same magnitude but opposite direction to the original gradient pulse is determined. The magnetic field force of the magnetic resonance imaging environment is adjusted by applying the original gradient pulse and the compensation gradient pulse to the magnetic resonance imaging environment. This method can apply a compensation gradient pulse to the magnetic resonance imaging environment on the basis of the original gradient pulse, so that the compensation gradient pulse and the original gradient pulse work together to weaken the magnetic field force of the magnetic resonance imaging environment on the ferromagnetic object. In this way, even if an additional compensation gradient pulse is applied to the magnetic resonance imaging environment, it will not affect the motion control of the ferromagnetic object, thereby achieving a better motion control effect and greatly increasing the accuracy of the actual motion of the ferromagnetic object. Attached Figure Description

[0036] Figure 1 This is a diagram illustrating the application environment of the magnetic field force adjustment method in one embodiment;

[0037] Figure 2 This is a flowchart illustrating a magnetic field force adjustment method in one embodiment;

[0038] Figure 3 This is a schematic diagram of a method for determining a compensated gradient pulse based on the magnetic force impulse of the original gradient pulse in one embodiment.

[0039] Figure 4 The waveform diagrams for an original gradient block and its corresponding compensated gradient block are shown in another embodiment.

[0040] Figure 5 This is a schematic diagram of a method for dividing the impulse gradient formed by the impulse of a magnetic force in another embodiment.

[0041] Figure 6 The waveform diagrams for two original gradient blocks and their corresponding compensated gradient blocks are shown in another embodiment.

[0042] Figure 7 This is a schematic diagram of a method for determining a compensated gradient pulse based on the magnetic field impulse of the original gradient pulse in another embodiment.

[0043] Figure 8 The image shows the waveforms of the radio frequency pulses and gradient pulses generated when the magnetic resonance scanning sequence is a fast spin echo sequence in one embodiment.

[0044] Figure 9 The waveform diagram shows the radio frequency pulses and gradient pulses generated when the magnetic resonance scanning sequence is a fast spin echo sequence, as well as the corresponding matched compensation gradient pulses, in another embodiment.

[0045] Figure 10 This is a structural block diagram of a magnetic field force adjustment device in one embodiment;

[0046] Figure 11 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0048] The magnetic field force adjustment method provided in this application can reduce the magnetic field force on ferromagnetic objects during magnetic resonance imaging, thereby minimizing the impact on the motion control of the ferromagnetic objects and enabling them to move to the lesion point in the medical image of the target object. Optionally, this magnetic field force adjustment method is applicable to... Figure 1 The magnetic resonance imaging (MRI) system shown includes an MRI device and a computer device. Optionally, the MRI device can be a permanent magnet MRI system, a conventionally conductive MRI system, or a superconducting MRI system, etc.; the computer device can be a standalone server or a server cluster consisting of multiple servers, and can also be, but is not limited to, various personal computers, laptops, smartphones, tablets, and portable wearable devices. The MRI device and the computer device can communicate with each other; the communication method can be a wired connection, Wi-Fi, mobile network, or Bluetooth connection, etc. The following embodiments will describe the implementation process of the magnetic field force adjustment method.

[0049] This application provides a method for adjusting magnetic field force, such as... Figure 2 The diagram shows a flowchart of the magnetic field force adjustment method. This method can introduce a gradient magnetic field during magnetic resonance imaging (MRI) without affecting the motion control of ferromagnetic objects. The following examples demonstrate the application of this method. Figure 1 Taking the magnetic resonance imaging system as an example, the magnetic field force adjustment method is explained. This magnetic field force adjustment method may include the following steps:

[0050] S100: Obtain the magnetic field impulse of the original gradient pulse in the magnetic resonance scanning sequence.

[0051] Specifically, the aforementioned magnetic resonance scanning sequence may include radio frequency (RF) pulses and gradient pulses; the RF pulses may include excitation RF pulses and refocusing RF pulses. Where no other gradient pulses are applied to the magnetic resonance imaging environment, the current gradient pulse can be referred to as the original gradient pulse.

[0052] It should be noted that the original gradient pulse has both magnitude and direction. Therefore, the computer equipment in the magnetic resonance imaging system can extract the original gradient pulse from the magnetic resonance scan sequence, and then integrate the magnetic field impulse of the original gradient pulse within the time range of the original gradient pulse to obtain the magnetic field impulse of the original gradient pulse. Optionally, since the magnetic field impulse of the original gradient pulse has both magnitude and direction, the result of integrating the magnetic field impulse of the original gradient pulse within the time range of the original gradient pulse can be either positive or negative, where positive and negative are used to distinguish the direction of the magnetic field impulse of the original gradient pulse.

[0053] Optionally, the original gradient pulse over a continuous time period can be represented by a trapezoid in the waveform diagram. In this case, the magnitude of the magnetic impulse of the original gradient pulse over the continuous time period can be equal to the area of ​​the trapezoid over that continuous time period.

[0054] Understandably, the computer equipment in a magnetic resonance imaging system can extract the original gradient pulse from the magnetic resonance scan sequence based on the distinguishing characteristics between the radio frequency pulse and the original gradient pulse. Optionally, the distinguishing characteristics between the radio frequency pulse and the original gradient pulse can be waveform characteristics, flip angle, etc.

[0055] Optionally, the magnetic resonance imaging sequence can be a spin echo sequence, a fast spin echo sequence, a gradient echo sequence, an inversion recovery sequence, a planar echo sequence, angiography sequences, and water imaging sequences, etc., and of course, other sequences are also possible.

[0056] S200. Determine the compensation gradient pulse based on the magnetic field impulse of the original gradient pulse; the magnetic field impulse of the original gradient pulse and the magnetic field impulse of the compensation gradient pulse are the same in magnitude and opposite in direction.

[0057] Specifically, the magnetic field strength generated by the radio frequency pulse is very small, and the magnetic force on the ferromagnetic object is negligible. This embodiment only considers the magnetic force on the ferromagnetic object caused by the magnetic field strength generated by the gradient pulse. Typically, introducing an additional gradient magnetic field into the magnetic resonance imaging environment introduces an additional magnetic force, thereby disrupting the target motion path of the ferromagnetic object, causing it to deviate from the target motion path and ultimately fail to reach the target position. In this embodiment, after applying a compensating gradient pulse to the magnetic resonance imaging environment, the magnetic force impulse of the original gradient pulse is set to be the same in magnitude but opposite in direction to the magnetic force impulse of the compensating gradient pulse, thus weakening the magnetic force of the magnetic resonance imaging environment on the ferromagnetic object. The computer equipment in the magnetic resonance imaging system can determine the compensating gradient pulse with the same magnitude but opposite direction based on the magnetic force impulse of the original gradient pulse.

[0058] Optionally, the boundary time points of the time range in which the original gradient pulse is located and the time range in which the compensated gradient pulse is located may be the same or different. Optionally, the interval duration corresponding to the time range in which the original gradient pulse is located and the interval duration corresponding to the time range in which the compensated gradient pulse is located may be equal or unequal.

[0059] For example, if the time range of the original gradient pulse is (1, 2), the time range of the compensated gradient pulse can be (2, 3) or (0, 1). This is a scenario where the boundary time points of the time range of the original gradient pulse and the time range of the compensated gradient pulse are the same, and the interval duration corresponding to the time range of the original gradient pulse is equal to the interval duration corresponding to the time range of the compensated gradient pulse.

[0060] Optionally, if the time range of the original gradient pulse is (1, 2), the time range of the compensated gradient pulse can be (2, 3.8) or (0.5, 1). This case is a scenario where the boundary time points of the time range of the original gradient pulse and the time range of the compensated gradient pulse are the same, and the interval duration corresponding to the time range of the original gradient pulse and the interval duration corresponding to the time range of the compensated gradient pulse are not equal.

[0061] Optionally, if the time range of the original gradient pulse is (1, 2), then the time range of the compensated gradient pulse can be (2.5, 3.8) or (0, 0.5). This is a scenario where the boundary time points of the time range of the original gradient pulse and the time range of the compensated gradient pulse are not the same, and the interval duration corresponding to the time range of the original gradient pulse and the interval duration corresponding to the time range of the compensated gradient pulse are not equal.

[0062] Optionally, if the time range of the original gradient pulse is (1, 2), then the time range of the compensated gradient pulse can be (2.5, 3) or (0, 0.5). This case is a scenario where the boundary time points of the time range of the original gradient pulse and the time range of the compensated gradient pulse are not the same, and the interval duration corresponding to the time range of the original gradient pulse is equal to the interval duration corresponding to the time range of the compensated gradient pulse.

[0063] S300. By applying the original gradient pulse and the compensated gradient pulse to the magnetic resonance imaging environment, the magnetic field force of the magnetic resonance imaging environment is adjusted; wherein, the adjusted magnetic field force exerts a force on the ferromagnetic object moving in the magnetic resonance imaging environment less than the preset force.

[0064] Specifically, the original gradient pulse can be the gradient pulse generated by the gradient coil in the magnetic resonance imaging device under normal conditions. Optionally, the aforementioned compensated gradient pulse can be an additional gradient pulse applied to the magnetic resonance imaging environment based on the original gradient pulse. Optionally, the compensated gradient pulse and the original gradient pulse work together to not only weaken the magnetic field force of the magnetic resonance imaging environment on the ferromagnetic object, but also to avoid affecting the imaging results, thereby controlling the movement of the ferromagnetic object through the magnetic resonance image, so that the ferromagnetic object moves from its current position to the target position.

[0065] Optionally, the adjusted magnetic field force exerted on a ferromagnetic object moving in the magnetic resonance imaging environment can be less than the preset force. Optionally, ideally, the preset force is equal to 0. However, since the magnetic resonance imaging environment may be affected by external environmental interference, leading to some error in the adjustment of the magnetic field force, the preset force can also be equal to a relatively small value such as 0.01 Gauss, 0.02 Gauss, or 0.05 Gauss.

[0066] It is understandable that the magnetic resonance imaging equipment in the magnetic resonance imaging system can directly receive the user's input request for applying a compensation gradient carrying a compensation gradient pulse, and after responding to the request, apply the compensation gradient pulse to the magnetic resonance imaging environment. That is, the compensation gradient pulse and the original gradient pulse are combined to obtain a combined gradient pulse, so as to reduce the magnetic field force of the magnetic resonance imaging environment on the ferromagnetic object.

[0067] Alternatively, the computer equipment in the magnetic resonance imaging (MRI) system can receive a compensation gradient application command input by the user and, in response, send a compensation gradient application request carrying a compensation gradient pulse to the MRI equipment. The MRI equipment, upon responding to the compensation gradient application request, applies the compensation gradient pulse to the MRI environment. In this case, the computer equipment can generate the corresponding compensation gradient application request after receiving the compensation gradient application command.

[0068] It should be noted that the input method for applying the compensation gradient can be a mouse, keyboard, voice, gesture, etc. Optionally, the timing of inputting the compensation gradient application command can be determined by the doctor or operator. The compensation gradient application command can be input at any time according to the need to reduce the magnetic field force, and there is no time limit.

[0069] Optionally, the above-mentioned compensation gradient application request may also carry an identifier for the compensation gradient pulse, which can indicate the specific location where the compensation gradient pulse is applied. Optionally, the above-mentioned combination of the compensation gradient pulse and the original gradient pulse can be understood as superimposing the compensation gradient pulses and / or the original gradient pulses corresponding to different times to obtain the combined gradient pulses corresponding to different times.

[0070] In the embodiments of this application, the compensation gradient pulse applied to the magnetic resonance imaging environment can be in any time range, but this time range does not coincide with the time range of the corresponding original gradient pulse.

[0071] In this process, after applying a compensated gradient pulse to the magnetic resonance imaging environment, magnetic resonance images of the imaging object can be continuously acquired, and ferromagnetic objects in the magnetic resonance images can be detected to monitor whether the ferromagnetic objects have moved to the target location of the imaging object. If it is determined that the ferromagnetic object has moved to the target location, the application of the compensated gradient pulse is stopped. Optionally, the target location can be a lesion point, target point, or other location in the tissue of the imaging object.

[0072] Optionally, the ferromagnetic object can move on the surface of the imaging object under the combined action of the compensated gradient pulse and the original gradient pulse. The magnetic resonance image generated during the movement of the ferromagnetic object from its current position to the target position can include an image of the region where the ferromagnetic object is located. Optionally, the magnetic resonance image can be an image of any tissue part of the imaging object.

[0073] In the magnetic field force adjustment method provided in this application embodiment, the magnetic resonance imaging system can acquire the magnetic field force impulse of the original gradient pulse in the magnetic resonance scanning sequence. Based on the magnetic field force impulse of the original gradient pulse, a compensation gradient pulse with the same magnitude but opposite direction to the original gradient pulse is determined. The magnetic field force of the magnetic resonance imaging environment is adjusted by applying the original gradient pulse and the compensation gradient pulse to the magnetic resonance imaging environment. This method can apply a compensation gradient pulse to the magnetic resonance imaging environment on the basis of the original gradient pulse, so that the compensation gradient pulse and the original gradient pulse work together to weaken the magnetic field force of the magnetic resonance imaging environment on the ferromagnetic object. In this way, even if an additional compensation gradient pulse is applied to the magnetic resonance imaging environment, it will not affect the motion control of the ferromagnetic object, thereby achieving a better motion control effect and greatly increasing the accuracy of the actual motion of the ferromagnetic object. Moreover, this will not affect the imaging results. At the same time, since this method does not affect the imaging results, it can also control the motion of the ferromagnetic object through the magnetic resonance image on the basis of the above method, so that the ferromagnetic object can move accurately from the current position to the target position.

[0074] The process of determining the compensation gradient pulse will be described below. In one embodiment, as... Figure 3 As shown, the step of determining the compensation gradient pulse based on the magnetic field impulse of the original gradient pulse in S200 above can be achieved through the following steps:

[0075] S210. Based on the magnetic force impulse of the original gradient pulse, divide the impulse gradient formed by the magnetic force impulse to obtain at least two original gradient blocks.

[0076] Specifically, in the gradient pulse waveform diagram, the impulse gradient formed by the magnetic force impulse can be represented by a trapezoid. Therefore, dividing the impulse gradient formed by the magnetic force impulse can be understood as dividing the trapezoid corresponding to the impulse gradient to obtain at least two original gradient blocks. Optionally, among all the obtained original gradient blocks, the size and direction of different original gradient blocks can be the same or different, and this embodiment of the application does not limit this.

[0077] Understandably, within the timeframe of the original gradient pulse, the computer device can determine the coordinates of all or part of the boundary points of the impulse gradient formed by the magnetic field force impulse of the original gradient pulse at each moment. The coordinates of all or part of the boundary points of the impulse gradient formed by the magnetic field force impulse include the coordinates of the corner points of the impulse gradient, in order to determine the magnitude and direction of the impulse gradient.

[0078] Furthermore, the computer device can divide the impulse gradient formed by the magnetic force impulse into at least two original gradient blocks based on the coordinates of all or part of the boundary points of the impulse gradient. Optionally, the computer device can also divide the impulse gradient formed by the magnetic force impulse into at equal time intervals based on the coordinates of all or part of the boundary points of the impulse gradient, thereby obtaining at least two original gradient blocks.

[0079] In addition, the computer device can determine the position of the flip angle of the radio frequency pulse, then determine the magnetic field impulse of the original gradient pulse that coincides with the position of the flip angle of the radio frequency pulse, and then divide the impulse gradient formed by the magnetic field impulse according to the coincident magnetic field impulse to obtain at least two original gradient blocks. Of course, the embodiments of this application can also use other methods to divide the impulse gradient formed by the magnetic field impulse to obtain at least two original gradient blocks.

[0080] S220. Determine the compensation gradient block corresponding to each original gradient block.

[0081] In this embodiment, the original gradient pulse may include at least two original gradient blocks, and correspondingly, the compensated gradient pulse corresponding to the original gradient pulse may also include at least two compensated gradient blocks. Optionally, the total number of original gradient blocks included in the original gradient pulse may be equal to the total number of compensated gradient blocks included in the corresponding compensated gradient pulse.

[0082] It should be noted that each original gradient block has a corresponding compensation gradient block; each original gradient block and its corresponding compensation gradient block can be equal. Optionally, the computer device can calculate the size of each original gradient block and determine the size and direction of the corresponding compensation gradient block based on the size and direction of each original gradient block.

[0083] The process of determining the compensation gradient block will be described below. In one embodiment, the step of determining the compensation gradient block corresponding to each original gradient block in S220 above may include: for any original gradient block, obtaining the area and direction of the original gradient block, and determining the gradient block with the same area and opposite direction as the original gradient block as the compensation gradient block corresponding to the original gradient block based on the area and direction of the original gradient block.

[0084] Specifically, for each original gradient block, a corresponding compensation gradient block needs to be matched so that the area difference between all original gradient blocks and all compensation gradient blocks is equal to 0.

[0085] Optionally, for any original gradient block, the computer device can integrate the magnetic impulse of the original gradient block within the time range of the original gradient block, and then take the absolute value of the integration result to obtain the area of ​​the original gradient block.

[0086] It should be noted that the integration result can be either positive or negative, with the sign used to distinguish the direction of the magnetic impulse of the original gradient block. In the embodiments of this application, the compensation gradient block corresponding to the original gradient block can also be directly determined from the integration result.

[0087] It is understandable that the interval length corresponding to the time range of the original gradient block and the interval length corresponding to the time range of the corresponding compensated gradient block may be equal or unequal; however, the area size of the compensated gradient block is the same as the area size of the corresponding original gradient block, and the direction of the compensated gradient block is opposite to the direction of the corresponding original gradient block.

[0088] For example, Figure 4 The image shows the waveform of a compensation gradient block A' matched with an original gradient block A. In practical applications, to reduce the magnetic field force exerted on ferromagnetic objects by the magnetic resonance imaging environment, the original gradient block A and the compensation gradient block A' are applied in pairs to the environment where the ferromagnetic object is located. The areas of the original gradient block A and the compensation gradient block A' are equal, their directions are opposite, and the time interval corresponding to the time range of the original gradient block is equal to the time interval corresponding to the time range of the compensation gradient block.

[0089] S230. Determine the compensation gradient pulse based on the compensation gradient block corresponding to each original gradient block.

[0090] Specifically, the computer device can combine the compensation gradient blocks corresponding to each original gradient block to obtain the compensation gradient pulse corresponding to the original gradient pulse.

[0091] Optionally, the combination of the compensation gradient blocks corresponding to each original gradient block can be understood as superimposing the compensation gradient blocks corresponding to different times to obtain the combined compensation gradient blocks corresponding to different times, i.e., compensation gradient pulses.

[0092] The magnetic field force adjustment method provided in this application embodiment can divide the impulse gradient formed by the magnetic field force impulse of the original gradient pulse to obtain at least two original gradient blocks, determine the compensation gradient block corresponding to each original gradient block, determine the compensation gradient pulse according to the compensation gradient block corresponding to each original gradient block, and further apply the compensation gradient pulse to the magnetic resonance imaging environment, so that the compensation gradient pulse and the original gradient pulse in the magnetic resonance imaging environment work together to weaken the magnetic field force of the magnetic resonance imaging environment on the ferromagnetic object, minimize the impact on the imaging results, and enable the ferromagnetic object to be accurately located in real time based on the magnetic resonance image, so that the ferromagnetic object can be accurately moved from the current position to the target position.

[0093] The following describes the process of dividing the impulse gradient formed by the magnetic force impulse according to embodiments of this application. In one embodiment, as... Figure 5 As shown, the step in S210 above, which divides the impulse gradient formed by the magnetic force impulse based on the magnetic force impulse of the original gradient pulse to obtain at least two original gradient blocks, can be achieved through the following steps:

[0094] S211. Obtain the equivalent center of the radio frequency pulse in the magnetic resonance scanning sequence.

[0095] Specifically, computer equipment can determine the equivalent center of radio frequency (RF) pulses in a magnetic resonance imaging (MRI) scan sequence using an equivalent center detection algorithm or an equivalent center point extraction algorithm. Alternatively, the equivalent center of the RF pulses can be determined using other methods. Optionally, the equivalent center of the RF pulses can be represented by a time point.

[0096] It should be noted that there may be one or more equivalent centers for the aforementioned radio frequency pulses.

[0097] S212. Based on the equivalent center and the magnetic impulse of the original gradient pulse, divide the impulse gradient to obtain at least two original gradient blocks.

[0098] Specifically, the computer device can divide the impulse gradient corresponding to the magnetic force impulse of the original gradient pulse at the location of the equivalent center of the radio frequency pulse to obtain at least two original gradient blocks. Alternatively, it can be understood that the computer device can divide the trapezoid corresponding to the original gradient pulse at the location of the equivalent center of the radio frequency pulse to obtain at least two original gradient blocks.

[0099] In this embodiment of the application, the total number of original gradient blocks obtained after partitioning can be equal to the total number of equivalent centers of radio frequency pulses plus 1.

[0100] in addition, Figure 6 The figure shows a radio frequency pulse RF over a certain period of time. The dashed line perpendicular to the imaging coordinate axis represents the location of the equivalent center of the radio frequency pulse. The equivalent center of the radio frequency pulse divides the magnetic field impulse of the original gradient pulse into two original gradient blocks A1' and A2. Furthermore, the above-mentioned magnetic field force adjustment method can be used to match the two original gradient blocks A1' and A2 with corresponding compensation pulse blocks A1 and A2'.

[0101] The magnetic field force adjustment method provided in this application embodiment can obtain the equivalent center of the radio frequency pulse in the magnetic resonance scanning sequence, and then divide the impulse gradient according to the equivalent center and the magnetic field force impulse of the original gradient pulse to obtain at least two original gradient blocks. Furthermore, each original gradient block is matched with a corresponding compensation gradient block and added to the magnetic resonance imaging environment so that the compensation gradient block and the original gradient block in the magnetic resonance imaging environment work together to weaken the magnetic field force of the magnetic resonance imaging environment on the ferromagnetic object.

[0102] In one embodiment, the magnetic resonance imaging environment is a three-dimensional space, and the original gradient pulses include original gradient pulses in the X direction, original gradient pulses in the Y direction, and original gradient pulses in the Z direction;

[0103] Then as Figure 7 As shown, the step of determining the compensation gradient pulse based on the magnetic field impulse of the original gradient pulse in S200 above may include:

[0104] S240. Based on the magnetic force impulse of the original gradient pulse in the target direction, determine the target direction compensation gradient pulse corresponding to the original gradient pulse in the target direction. The original gradient pulse in the target direction is at least one of the original gradient pulses in the X, Y, and Z directions.

[0105] Specifically, the computer device can determine the magnetic field impulse of the original gradient pulse in the target direction at different times, and then divide the impulse gradient formed by the magnetic field impulse according to the magnetic field impulse of the original gradient pulse in the target direction to obtain at least two original gradient blocks in the target direction, and determine the target direction compensation gradient block corresponding to each original gradient block in the target direction. Then, according to the target direction compensation gradient block corresponding to each original gradient block in the target direction, the target direction compensation gradient pulse corresponding to the original gradient pulse in the target direction is determined.

[0106] Optionally, the original gradient pulse in the target direction is at least one of the original gradient pulses in the X, Y, and Z directions. Correspondingly, the compensated gradient pulse in the target direction can be at least one of the compensated gradient pulses in the X, Y, and Z directions. The original gradient pulse in the target direction and the corresponding compensated gradient pulse in the target direction have the same magnitude but opposite directions.

[0107] S250. Determine the compensation gradient pulse based on the target direction compensation gradient pulse.

[0108] Specifically, the computer device can combine the X-direction compensation gradient pulse, Y-direction compensation gradient pulse and / or Z-direction compensation gradient pulse in the three-dimensional coordinate system at different times to obtain the compensation gradient pulse corresponding to the current original gradient pulse.

[0109] The original gradient pulses in the X, Y, and Z directions can be the same or different; correspondingly, the compensated gradient pulses in the X, Y, and Z directions can also be the same or different.

[0110] For example, Figure 8 The waveforms of the radio frequency pulses and gradient pulses generated after a fast spin echo sequence is applied to the environment of the imaging object are shown. Figure 8 The diagram shows gradient blocks in three different directions of 3D space for gradient impulse decomposition, where GS represents the Z direction, GP represents the Y direction, and GR represents the X direction. Figure 8 The horizontal axis represents the imaging coordinate axes in three different directions. The trapezoids on either side of the horizontal axis represent the waveforms of the original gradient blocks in three different directions. The dashed lines perpendicular to the horizontal axis represent the position of the flip angle of the RF pulse within the RF pulse. From... Figure 8 As can be seen, the magnetic field impulse of the overall original gradient block is not zero at each time step on the imaging coordinate axis in each direction. Therefore, it is necessary to match a corresponding compensation gradient block for each original gradient block so that the sum of the magnetic field impulse of the overall original gradient block and the magnetic field impulse of the compensation gradient block is zero at each time step.

[0111] in addition, Figure 9 The waveforms are shown for the radio frequency pulse generated after a fast spin echo sequence is applied to the environment of the imaging object, the original gradient blocks in three different directions in three-dimensional space, and the corresponding compensated gradient blocks. Figure 9 The dashed boxes in the image represent the waveforms of the original gradient block and the corresponding compensated gradient block. Figure 9 The waveforms of the original gradient block and the corresponding compensated gradient block are centrally symmetric.

[0112] The magnetic field force adjustment method provided in this application embodiment can determine the target direction compensation gradient pulse corresponding to the original gradient pulse in the target direction based on the magnetic field force impulse of the original gradient pulse in the target direction, and determine the compensation gradient pulse based on the target direction compensation gradient pulse. This method can acquire compensation gradient pulses in three dimensions, and further add the compensation gradient pulses in three dimensions to the magnetic resonance imaging environment to achieve a better effect of reducing the magnetic field force of the magnetic resonance imaging environment on ferromagnetic objects. Furthermore, on the basis of a good reduction effect of magnetic field force, it can also improve the accuracy of the acquired magnetic resonance images.

[0113] In some scenarios, to ensure that a ferromagnetic object can move to the target position, it is necessary to continuously acquire magnetic resonance images after weakening the magnetic field force of the magnetic resonance imaging environment on the ferromagnetic object, so as to determine whether the ferromagnetic object has moved to the target position by using the position of the ferromagnetic object in the magnetic resonance images. Therefore, in one embodiment, the above-mentioned magnetic field force adjustment method further includes the following steps: acquiring radio frequency signal data generated by the imaging object in the magnetic resonance imaging environment under the excitation of the adjusted magnetic resonance scanning sequence, and generating a magnetic resonance image of the imaging object based on the radio frequency signal data. The adjusted magnetic resonance scanning sequence includes radio frequency pulses, original gradient pulses, and compensated gradient pulses.

[0114] Specifically, the magnetic resonance scanning sequence after adjusting the magnetic field force can include radio frequency pulses, original gradient pulses, and compensated gradient pulses.

[0115] It should be noted that after applying a compensated gradient pulse in the magnetic field imaging environment where the imaging object is located, the combined effect of the radio frequency pulse, the original gradient pulse, and the compensated gradient pulse on the imaging object will excite the protons in the imaging object to resonate. At this time, the magnetic resonance imaging device can acquire the radio frequency signal data generated by the imaging object.

[0116] Furthermore, the magnetic resonance imaging (MRI) device can send the radio frequency signal data generated by the acquired imaging object to a computer device, which then performs image reconstruction on the radio frequency signal data to obtain a magnetic resonance image.

[0117] In the magnetic resonance imaging environment, after applying a compensated gradient pulse, the computer equipment can continuously acquire magnetic resonance images. At the same time, it performs target detection and / or localization analysis on each acquired magnetic resonance image to determine the position of the ferromagnetic object in each magnetic resonance image, and thus determine whether the ferromagnetic object has moved to the target position based on the position of the ferromagnetic object.

[0118] The magnetic field force adjustment method provided in this application embodiment can continuously acquire magnetic resonance images after applying a compensation gradient pulse in the magnetic resonance imaging environment, and monitor whether the ferromagnetic object has moved to the target position based on the real-time acquired magnetic resonance images, thereby enabling accurate positioning of the target position of the imaging object.

[0119] To facilitate understanding by those skilled in the art, the magnetic resonance imaging method provided in this application is described using a computer device as the execution subject as an example. Specifically, the method includes:

[0120] (1) Obtain the magnetic field impulse of the original gradient pulse in the magnetic resonance scanning sequence.

[0121] (2) Obtain the equivalent center of the radio frequency pulse in the magnetic resonance scanning sequence;

[0122] (3) Based on the equivalent center and the magnetic force impulse of the original gradient pulse, the impulse gradient is divided to obtain at least two original gradient blocks.

[0123] (4) For any original gradient block, obtain the area size and direction of the original gradient block, and determine the gradient block with the same area size and opposite direction as the original gradient block as the compensation gradient block corresponding to the original gradient block based on the area size and direction of the original gradient block.

[0124] (5) Determine the compensation gradient pulse based on the compensation gradient block corresponding to each original gradient block; the magnetic force impulse of the original gradient pulse and the magnetic force impulse of the compensation gradient pulse are the same in magnitude and opposite in direction.

[0125] (6) Acquire radio frequency signal data generated by the imaging object in the magnetic resonance imaging environment under the excitation of the adjusted magnetic resonance scanning sequence; the adjusted magnetic resonance scanning sequence includes radio frequency pulses, original gradient pulses and compensated gradient pulses;

[0126] (7) Generate a magnetic resonance image of the imaging object based on the radio frequency signal data.

[0127] The specific execution process of (1) to (7) above can be found in the description of the above embodiments. The implementation principle and technical effect are similar, and will not be repeated here.

[0128] It should be understood that, although Figure 2 , 3 The steps in flowcharts 5 and 7 are shown sequentially as indicated by the arrows; however, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order requirement for the execution of these steps, and they can be performed in other orders. Furthermore, Figure 2 , 3At least some of the steps in 5 and 7 may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but may be executed at different times. The execution order of these steps or stages is not necessarily sequential, but may be executed in turn or alternately with other steps or at least some of the steps or stages in other steps.

[0129] In one embodiment, such as Figure 10 As shown, a magnetic field force adjustment device is provided, including: a magnetic field force impulse acquisition module 11, a compensation pulse determination module 12, and a magnetic field force adjustment module 13, wherein:

[0130] The magnetic field force impulse acquisition module 11 is used to acquire the magnetic field force impulse of the original gradient pulse in the magnetic resonance scanning sequence.

[0131] The compensation pulse determination module 12 is used to determine the compensation gradient pulse based on the magnetic field impulse of the original gradient pulse; the magnetic field impulse of the original gradient pulse and the magnetic field impulse of the compensation gradient pulse are the same in magnitude and opposite in direction.

[0132] The magnetic field force adjustment module 13 is used to adjust the magnetic field force of the magnetic resonance imaging environment by applying the original gradient pulse and the compensation gradient pulse to the magnetic resonance imaging environment; wherein, the adjusted magnetic field force exerts a force on the ferromagnetic object moving in the magnetic resonance imaging environment less than the preset force.

[0133] The magnetic field force adjustment device provided in this embodiment can perform the above method embodiment, and its implementation principle and technical effect are similar, so it will not be described again here.

[0134] In one embodiment, the compensation pulse determination module 12 includes: a partitioning unit, a compensation gradient block determination unit, and a first determination unit, wherein:

[0135] A partitioning unit is used to partition the impulse gradient formed by the magnetic force impulse based on the magnetic force impulse of the original gradient pulse, so as to obtain at least two original gradient blocks.

[0136] The compensation gradient block determination unit is used to determine the compensation gradient block corresponding to each original gradient block.

[0137] The first determining unit is used to determine the compensation gradient pulse based on the compensation gradient block corresponding to each original gradient block.

[0138] The magnetic field force adjustment device provided in this embodiment can perform the above method embodiment, and its implementation principle and technical effect are similar, so it will not be described again here.

[0139] In one embodiment, the partitioning unit includes: an equivalent center acquisition subunit and a partitioning subunit, wherein:

[0140] The equivalent center acquisition subunit is used to acquire the equivalent center of the radio frequency pulse in the magnetic resonance scanning sequence;

[0141] The sub-unit is used to divide the impulse gradient according to the equivalent center and the magnetic force impulse of the original gradient pulse, so as to obtain at least two original gradient blocks.

[0142] The magnetic field force adjustment device provided in this embodiment can perform the above method embodiment, and its implementation principle and technical effect are similar, so it will not be described again here.

[0143] In one embodiment, the compensation gradient block determination unit is specifically used to obtain the area size and direction of any original gradient block, and determine the gradient block with the same area size and opposite direction as the compensation gradient block corresponding to the original gradient block based on the area size and direction of the original gradient block.

[0144] The magnetic field force adjustment device provided in this embodiment can perform the above method embodiment, and its implementation principle and technical effect are similar, so it will not be described again here.

[0145] In one embodiment, the original gradient pulse includes an original gradient pulse in the X direction, an original gradient pulse in the Y direction, and an original gradient pulse in the Z direction; the compensation pulse determination module 12 includes: a target compensation pulse determination unit and a second determination unit, wherein:

[0146] The target compensation pulse determination unit is used to determine the target direction compensation gradient pulse corresponding to the original gradient pulse in the target direction based on the magnetic force impulse of the original gradient pulse in the target direction; the original gradient pulse in the target direction is at least one of the original gradient pulse in the X direction, the original gradient pulse in the Y direction, and the original gradient pulse in the Z direction.

[0147] The second determining unit is used to determine the compensation gradient pulse based on the target direction compensation gradient pulse.

[0148] The magnetic field force adjustment device provided in this embodiment can perform the above method embodiment, and its implementation principle and technical effect are similar, so it will not be described again here.

[0149] In one embodiment, the magnetic field force adjustment device further includes: a radio frequency data acquisition module and an image generation module, wherein:

[0150] The radio frequency data acquisition module is used to acquire radio frequency signal data generated by the imaging object in the magnetic resonance imaging environment under the excitation of the adjusted magnetic resonance scanning sequence; the adjusted magnetic resonance scanning sequence includes radio frequency pulses, original gradient pulses, and compensated gradient pulses.

[0151] The image generation module is used to generate magnetic resonance images of the imaging object based on radio frequency signal data.

[0152] The magnetic field force adjustment device provided in this embodiment can perform the above method embodiment, and its implementation principle and technical effect are similar, so it will not be described again here.

[0153] Specific limitations regarding the magnetic field force adjustment device can be found in the limitations of the magnetic resonance imaging method above, and will not be repeated here. Each module in the aforementioned magnetic field force adjustment device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware or independently of the processor in a computer device, or stored in software in the memory of a computer device, so that the processor can call and execute the corresponding operations of each module.

[0154] In one embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 11 As shown, the computer device includes a processor, memory, and a network interface connected via a system bus. The processor provides computational and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The database is used for magnetic resonance imaging. The network interface is used for communication with external endpoints via a network connection. When the computer program is executed by the processor, it implements a magnetic resonance imaging method.

[0155] Those skilled in the art will understand that Figure 11 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.

[0156] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps:

[0157] Obtain the magnetic force impulse of the original gradient pulse in the magnetic resonance scanning sequence;

[0158] The compensated gradient pulse is determined based on the magnetic field impulse of the original gradient pulse; the magnetic field impulse of the original gradient pulse and the magnetic field impulse of the compensated gradient pulse are the same in magnitude and opposite in direction.

[0159] The magnetic field force of the magnetic resonance imaging environment is adjusted by applying the original gradient pulse and the compensated gradient pulse to the magnetic resonance imaging environment; wherein the adjusted magnetic field force exerts a smaller force on ferromagnetic objects moving in the magnetic resonance imaging environment than the preset force.

[0160] In one embodiment, a readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, performs the following steps:

[0161] Obtain the magnetic force impulse of the original gradient pulse in the magnetic resonance scanning sequence;

[0162] The compensated gradient pulse is determined based on the magnetic field impulse of the original gradient pulse; the magnetic field impulse of the original gradient pulse and the magnetic field impulse of the compensated gradient pulse are the same in magnitude and opposite in direction.

[0163] The magnetic field force of the magnetic resonance imaging environment is adjusted by applying the original gradient pulse and the compensated gradient pulse to the magnetic resonance imaging environment; wherein the adjusted magnetic field force exerts a smaller force on ferromagnetic objects moving in the magnetic resonance imaging environment than the preset force.

[0164] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, performs the following steps:

[0165] Obtain the magnetic force impulse of the original gradient pulse in the magnetic resonance scanning sequence;

[0166] The compensated gradient pulse is determined based on the magnetic field impulse of the original gradient pulse; the magnetic field impulse of the original gradient pulse and the magnetic field impulse of the compensated gradient pulse are the same in magnitude and opposite in direction.

[0167] The magnetic field force of the magnetic resonance imaging environment is adjusted by applying the original gradient pulse and the compensated gradient pulse to the magnetic resonance imaging environment; wherein the adjusted magnetic field force exerts a smaller force on ferromagnetic objects moving in the magnetic resonance imaging environment than the preset force.

[0168] This application provides a magnetic resonance imaging system; see also the structural diagram of the magnetic resonance imaging system. Figure 1 As shown. The magnetic resonance imaging system includes: magnetic resonance imaging equipment and computer equipment;

[0169] The computer equipment is used to acquire the magnetic field impulse of the original gradient pulse in the magnetic resonance scanning sequence, and to determine the compensation gradient pulse based on the magnetic field impulse of the original gradient pulse; the magnetic field impulse of the original gradient pulse and the magnetic field impulse of the compensation gradient pulse are the same in magnitude and opposite in direction.

[0170] Magnetic resonance imaging equipment is used to adjust the magnetic field force of the magnetic resonance imaging environment by applying original gradient pulses and compensated gradient pulses to the magnetic resonance imaging environment; wherein, the adjusted magnetic field force exerts a force on ferromagnetic objects moving in the magnetic resonance imaging environment less than a preset force.

[0171] The magnetic resonance imaging system provided in this embodiment can execute the above-described method embodiments, and its implementation principle and technical effect are similar, so they will not be described again here.

[0172] In one embodiment, the computer device is specifically configured to divide the impulse gradient formed by the magnetic force impulse of the original gradient pulse into at least two original gradient blocks, determine the compensation gradient block corresponding to each original gradient block, and determine the compensation gradient pulse based on the compensation gradient block corresponding to each original gradient block.

[0173] The magnetic resonance imaging system provided in this embodiment can execute the above-described method embodiments, and its implementation principle and technical effect are similar, so they will not be described again here.

[0174] In one embodiment, the computer device is specifically used to obtain the equivalent center of the radio frequency pulse in the magnetic resonance scanning sequence, and to divide the impulse gradient according to the equivalent center and the magnetic field impulse of the original gradient pulse to obtain at least two original gradient blocks.

[0175] The magnetic resonance imaging system provided in this embodiment can execute the above-described method embodiments, and its implementation principle and technical effect are similar, so they will not be described again here.

[0176] In one embodiment, the computer device is specifically configured to, for any given original gradient block, obtain the area size and orientation of the original gradient block, and, based on the area size and orientation of the original gradient block, determine a gradient block with the same area size but opposite orientation as the compensation gradient block corresponding to the original gradient block.

[0177] The magnetic resonance imaging system provided in this embodiment can execute the above-described method embodiments, and its implementation principle and technical effect are similar, so they will not be described again here.

[0178] In one embodiment, the original gradient pulse includes an original gradient pulse in the X direction, an original gradient pulse in the Y direction, and an original gradient pulse in the Z direction; the computer device is specifically used to determine the target direction compensation gradient pulse corresponding to the original gradient pulse in the target direction based on the magnetic force impulse of the original gradient pulse in the target direction, and to determine the compensation gradient pulse based on the compensation gradient pulse in the target direction; the original gradient pulse in the target direction is at least one of the original gradient pulse in the X direction, the original gradient pulse in the Y direction, and the original gradient pulse in the Z direction.

[0179] The magnetic resonance imaging system provided in this embodiment can execute the above-described method embodiments, and its implementation principle and technical effect are similar, so they will not be described again here.

[0180] In one embodiment, the computer device is further configured to acquire radio frequency signal data generated by the imaging object in the magnetic resonance imaging environment under the excitation of the adjusted magnetic resonance scanning sequence, and generate a magnetic resonance image of the imaging object based on the radio frequency signal data; the adjusted magnetic resonance scanning sequence includes radio frequency pulses, original gradient pulses and compensated gradient pulses.

[0181] The magnetic resonance imaging system provided in this embodiment can execute the above-described method embodiments, and its implementation principle and technical effect are similar, so they will not be described again here.

[0182] Those skilled in the art will understand that all or part of the processes in the methods of 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, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, 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, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0183] 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.

[0184] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for adjusting magnetic field force, characterized in that, The method includes: Obtain the magnetic force impulse of the original gradient pulse in the magnetic resonance scanning sequence; The compensation gradient pulse is determined based on the magnetic field impulse of the original gradient pulse; the magnetic field impulse of the original gradient pulse and the magnetic field impulse of the compensation gradient pulse are the same in magnitude and opposite in direction. By applying the original gradient pulse and the compensated gradient pulse to the magnetic resonance imaging environment, the magnetic field force of the magnetic resonance imaging environment is adjusted; wherein, the adjusted magnetic field force exerts a smaller force on ferromagnetic objects moving in the magnetic resonance imaging environment than a preset force. The determination of the compensated gradient pulse based on the magnetic field impulse of the original gradient pulse includes: Obtain the equivalent center of the radio frequency pulse in the magnetic resonance scanning sequence. Based on the equivalent center and the magnetic field impulse of the original gradient pulse, divide the impulse gradient formed by the magnetic field impulse to obtain at least two original gradient blocks. For any original gradient block, obtain the area and direction of the original gradient block. Based on the area and direction of the original gradient block, determine the gradient block with the same area and opposite direction as the compensation gradient block corresponding to the original gradient block. Determine the compensation gradient pulse based on the compensation gradient blocks corresponding to each original gradient block.

2. The magnetic field force adjustment method according to claim 1, characterized in that, The original gradient pulses include the original gradient pulses in the X direction, the original gradient pulses in the Y direction, and the original gradient pulses in the Z direction; The determination of the compensated gradient pulse based on the magnetic field impulse of the original gradient pulse includes: Based on the magnetic impulse of the original gradient pulse in the target direction, the target direction compensation gradient pulse corresponding to the original gradient pulse in the target direction is determined; the original gradient pulse in the target direction is at least one of the original gradient pulse in the X direction, the original gradient pulse in the Y direction, and the original gradient pulse in the Z direction. The compensation gradient pulse is determined based on the target direction compensation gradient pulse.

3. The magnetic field force adjustment method according to claim 2, characterized in that, The step of determining the compensation gradient pulse based on the target direction compensation gradient pulse includes: The compensation gradient pulse is obtained by combining the X-direction compensation gradient pulse, Y-direction compensation gradient pulse and / or Z-direction compensation gradient pulse in the target direction compensation gradient pulse.

4. The magnetic force adjustment method according to any one of claims 1-3, characterized in that, The method further includes: The radio frequency signal data generated by the imaging object in the magnetic resonance imaging environment under the excitation of the adjusted magnetic resonance scanning sequence are acquired; the adjusted magnetic resonance scanning sequence includes radio frequency pulses, the original gradient pulses, and the compensated gradient pulses; A magnetic resonance image of the imaging object is generated based on the radio frequency signal data.

5. A magnetic field force adjustment device, characterized in that, The device includes: The magnetic field impulse acquisition module is used to acquire the magnetic field impulse of the original gradient pulse in the magnetic resonance scanning sequence. The compensation pulse determination module is used to determine the compensation gradient pulse based on the magnetic field impulse of the original gradient pulse; the magnetic field impulse of the original gradient pulse and the magnetic field impulse of the compensation gradient pulse are the same in magnitude and opposite in direction. The magnetic field force adjustment module is used to adjust the magnetic field force of the magnetic resonance imaging environment by applying the original gradient pulse and the compensated gradient pulse to the magnetic resonance imaging environment; wherein the adjusted magnetic field force exerts a force on a ferromagnetic object moving in the magnetic resonance imaging environment less than a preset force. The compensation pulse determination module is used to obtain the equivalent center of the radio frequency pulse in the magnetic resonance scanning sequence, divide the impulse gradient formed by the magnetic field impulse into at least two original gradient blocks based on the equivalent center and the magnetic field impulse of the original gradient pulse, obtain the area and direction of the original gradient block for any original gradient block, and determine the gradient block with the same area and opposite direction as the original gradient block as the compensation gradient block corresponding to the original gradient block based on the area and direction of the original gradient block, and determine the compensation gradient pulse based on the compensation gradient block corresponding to each original gradient block.

6. The apparatus according to claim 5, characterized in that, The original gradient pulses include the original gradient pulses in the X direction, the original gradient pulses in the Y direction, and the original gradient pulses in the Z direction; The compensation pulse determination module includes: The target compensation pulse determination unit is used to determine the target direction compensation gradient pulse corresponding to the original gradient pulse in the target direction based on the magnetic force impulse of the original gradient pulse in the target direction; the original gradient pulse in the target direction is at least one of the original gradient pulse in the X direction, the original gradient pulse in the Y direction, and the original gradient pulse in the Z direction. The second determining unit is used to determine the compensation gradient pulse based on the target direction compensation gradient pulse.

7. The apparatus according to claim 5 or 6, characterized in that, The device further includes: The radio frequency data acquisition module is used to acquire radio frequency signal data generated by the imaging object in the magnetic resonance imaging environment under the excitation of the adjusted magnetic resonance scanning sequence; the adjusted magnetic resonance scanning sequence includes radio frequency pulses, the original gradient pulses, and the compensated gradient pulses. An image generation module is used to generate a magnetic resonance image of the imaging object based on the radio frequency signal data.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the magnetic force adjustment method according to any one of claims 1-4.

9. A readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the magnetic force adjustment method according to any one of claims 1-4.

10. A magnetic resonance imaging system, comprising magnetic resonance imaging equipment and computer equipment, characterized in that, The computer device is used to acquire the magnetic field impulse of the original gradient pulse in the magnetic resonance scanning sequence, and to determine the compensation gradient pulse based on the magnetic field impulse of the original gradient pulse; the magnetic field impulse of the original gradient pulse and the magnetic field impulse of the compensation gradient pulse are the same in magnitude and opposite in direction. The magnetic resonance imaging device is used to adjust the magnetic field force of the magnetic resonance imaging environment by applying the original gradient pulse and the compensated gradient pulse to the magnetic resonance imaging environment; wherein the adjusted magnetic field force exerts a force on a ferromagnetic object moving in the magnetic resonance imaging environment less than a preset force. The determination of the compensated gradient pulse based on the magnetic field impulse of the original gradient pulse includes: Obtain the equivalent center of the radio frequency pulse in the magnetic resonance scanning sequence. Based on the equivalent center and the magnetic field impulse of the original gradient pulse, divide the impulse gradient formed by the magnetic field impulse to obtain at least two original gradient blocks. For any original gradient block, obtain the area and direction of the original gradient block. Based on the area and direction of the original gradient block, determine the gradient block with the same area and opposite direction as the compensation gradient block corresponding to the original gradient block. Determine the compensation gradient pulse based on the compensation gradient blocks corresponding to each original gradient block.

Images