Magnetic resonance scanning method and device with variable shimming parameters and computer equipment

Abstract

The invention relates to a magnetic resonance scanning method and device with variable shimming parameters, computer equipment and a storage medium, and the method comprises the steps: determining a first shimming region and a second shimming region in a positioning image based on the collected positioning image before sequence scanning; shimming the first shimming area to obtain a first shimming parameter; shimming the second shimming area to obtain a second shimming parameter; and in sequence scanning execution, repeatedly switching the first shimming parameter or the second shimming parameter to a corresponding working module, so that a preparation module in the working module adopts the first shimming parameter to image a first shimming area, and an acquisition module in the working module adopts the second shimming parameter to image a second shimming area. Through the method and the device, the problem of low magnetic resonance imaging quality caused by high shimming difficulty of a shimming mode of a single shimming region in the same imaging sequence in the prior art is solved, the shimming difficulty is reduced, and the magnetic resonance imaging quality is improved.

Description

Technical Field

[0001] The present application relates to the field of magnetic resonance imaging, and particularly to a magnetic resonance scanning method, apparatus, and computer device with variable shimming parameters. Background Art

[0002] In magnetic resonance imaging, the uniformity of the main magnetic field B0 is an important indicator, and its quality directly affects the imaging quality. For general conventional sequences, the uniformity of the main magnetic field B0 will affect the deformation, signal-to-noise ratio, and slice selection accuracy of the imaging. For some high-order sequences, mainly high-speed sequences and sequences related to chemical shift spectra, the requirements for the uniformity of the main magnetic field B0 are more stringent.

[0003] In current magnetic resonance scanning methods, a single shimming area shimming method is used under the same imaging sequence. However, for imaging across multiple tissue regions of a living body, affected by the cavity area of the shimming area and the tissue interface, the shimming effect not only makes it difficult to ensure the uniformity of the main magnetic field B0 in the imaging area and the preparation area, but also increases the shimming difficulty, resulting in low magnetic resonance imaging quality.

[0004] Regarding the problem that in the related art, the single shimming area shimming method under the same imaging sequence has high shimming difficulty and results in low magnetic resonance imaging quality, no effective solution has been proposed yet. Summary of the Invention

[0005] In this embodiment, a magnetic resonance scanning method, apparatus, and computer device with variable shimming parameters are provided to solve the problem that in the related art, the single shimming area shimming method under the same imaging sequence has high shimming difficulty and results in low magnetic resonance imaging quality.

[0006] In a first aspect, in this embodiment, a magnetic resonance scanning method with variable shimming parameters is provided, and the method includes:

[0007] Before sequence scanning, based on the acquired localization image, determine a first shimming area and a second shimming area in the localization image;

[0008] Perform shimming on the first shimming area to obtain a first shimming parameter;

[0009] Perform shimming on the second shimming area to obtain a second shimming parameter;

[0010] During sequence scanning execution, repeatedly switch the first shimming parameter or the second shimming parameter to the corresponding working module, so that the preparation module in the working module uses the first shimming parameter to image the first shimming area, and the acquisition module in the working module uses the second shimming parameter to image the second shimming area.

[0011] In some of these embodiments, repeatedly switching the first shimming parameter or the second shimming parameter into the corresponding working module, such that the preparation module in the working module uses the first shimming parameter to image the first shimming region, and the acquisition module in the working module uses the second shimming parameter to image the second shimming region, includes:

[0012] Before the preparation module in the working module executes, switch the first shimming parameter into the preparation module in the working module, such that the preparation module uses the first shimming parameter to image the first shimming region;

[0013] Before the acquisition module in the working module executes, switch the second shimming parameter into the acquisition module in the working module, such that the acquisition module uses the second shimming parameter to image the second shimming region;

[0014] Repeatedly switch the first shimming parameter or the second shimming parameter into the corresponding working module until the serial scan is completed.

[0015] In some of these embodiments, the method further includes:

[0016] After the preparation module in the working module executes, determine whether a first available switching time conforms to a preset time threshold; the first available switching time is the available time for switching the first shimming parameter to the second shimming parameter;

[0017] When the first available switching time conforms to the preset time threshold, switch the compensation currents of the second shimming coils from zero order to high order;

[0018] When the first available switching time does not conform to the preset time threshold, switch the compensation currents of the zero-order and first-order second shimming coils.

[0019] In some of these embodiments, the method further includes:

[0020] After the acquisition module in the working module executes, determine whether a second available switching time conforms to a preset time threshold; the second available switching time is the available time for switching the second shimming parameter to the first shimming parameter;

[0021] When the second available switching time conforms to the preset time threshold, switch the compensation currents of the first shimming coils from zero order to high order;

[0022] When the second available switching time does not conform to the preset time threshold, switch the compensation currents of the zero-order and first-order first shimming coils.

[0023] In some of these embodiments, the sequence is a perfusion sequence;

[0024] When having the first available switching time, the first available switching time is a marked extended period;

[0025] Or, when having the second available switching time, the second available switching time is a marked extended period.

[0026] In some embodiments thereof, shimming is performed on the first shimming region to obtain first shimming parameters, including:

[0027] Performing main magnetic field B0 shimming on the first shimming region, and when the shimming result meets the main magnetic field B0 uniformity index of the full width at half maximum, obtaining first shimming parameters; the first shimming parameters include first shimming coil compensation currents from zero order to high order.

[0028] In some embodiments thereof, shimming is performed on the second shimming region to obtain second shimming parameters, including:

[0029] Performing main magnetic field B0 shimming on the second shimming region, and when the shimming result meets the main magnetic field B0 uniformity index of the full width at half maximum, obtaining second shimming parameters; the second shimming parameters include second shimming coil compensation currents from zero order to high order.

[0030] In a second aspect, a magnetic resonance scanning device with variable shimming parameters is provided in this embodiment, including: a processing module, a first shimming module, a second shimming module, and an imaging module;

[0031] The processing module is configured to determine a first shimming region and a second shimming region in the positioning image based on the acquired positioning image before sequence scanning;

[0032] The first shimming module is configured to perform shimming on the first shimming region to obtain first shimming parameters;

[0033] The second shimming module is configured to perform shimming on the second shimming region to obtain second shimming parameters;

[0034] The imaging module is configured to repeatedly switch the first shimming parameters or the second shimming parameters to the corresponding working modules during sequence scanning execution, so that the preparation module in the working module uses the first shimming parameters to image the first shimming region, and the acquisition module in the working module uses the second shimming parameters to image the second shimming region.

[0035] In a third aspect, a computer device is provided in this embodiment, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the magnetic resonance scanning method with variable shimming parameters described in the first aspect above is implemented.

[0036] In a fourth aspect, a magnetic resonance imaging system is provided in this embodiment, including: a scanning device and an imaging device; wherein, the scanning device is connected to the imaging device;

[0037] The scanning device is used to implement the magnetic resonance scanning method with variable shimming parameters described in the first aspect above when executed;

[0038] The imaging device is used to perform imaging based on the scanning result to obtain a target magnetic resonance image.

[0039] Compared with the related art, in the magnetic resonance scanning method, device, computer device, and storage medium with variable shimming parameters provided in this embodiment, before the sequence scanning, based on the acquired localization image, the first shimming region and the second shimming region in the localization image are determined; the first shimming region is shimmed to obtain the first shimming parameter; the second shimming region is shimmed to obtain the second shimming parameter; during the execution of the sequence scanning, the first shimming parameter or the second shimming parameter is repeatedly switched to the corresponding working module, so that the preparation module in the working module uses the first shimming parameter to image the first shimming region, and the acquisition module in the working module uses the second shimming parameter to image the second shimming region, solving the problem in the related art that the shimming method in a single shimming region under the same imaging sequence has a high shimming difficulty, resulting in low magnetic resonance imaging quality, and realizing switching the shimming parameters to the corresponding working module under the same imaging sequence to image the corresponding shimming regions, thereby reducing the shimming difficulty and improving the magnetic resonance imaging quality.

[0040] The details of one or more embodiments of the present application are set forth in the following drawings and description to make the other features, objects, and advantages of the present application more concise and understandable. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings:

[0042] Figure 1 is a schematic hardware structure diagram of a magnetic resonance imaging system provided by an embodiment of the present application;

[0043] Figure 2 is a flowchart of a magnetic resonance scanning method with variable shimming parameters provided by an embodiment of the present application;

[0044] Figure 3 is Figure 2 The flowchart of step S240 in

[0045] Figure 4 is the schematic diagram of the positioning image provided by an embodiment of the present application;

[0046] Figure 5 is the schematic diagram of the shimming parameter switching provided by an embodiment of the present application;

[0047] Figure 6 is the schematic flow diagram of the magnetic resonance scanning method with variable shimming parameters provided by a preferred embodiment of the present application;

[0048] Figure 7 is the structural block diagram of the magnetic resonance scanning device with variable shimming parameters provided by an embodiment of the present application. Detailed implementation manners

[0049] For a clearer understanding of the purpose, technical solution and advantages of the present application, the present application will be described and illustrated below with reference to the accompanying drawings and embodiments.

[0050] Unless otherwise defined, the technical terms or scientific terms involved in the present application shall have the general meaning understood by those with ordinary skills in the technical field to which the present application belongs. In the present application, words such as "a", "one", "kind", "the", "these" and the like do not indicate a limitation in quantity, and they can be singular or plural. The terms "including", "comprising", "having" and any variants thereof involved in the present application are intended to cover non-exclusive inclusion; for example, a process, method, system, product or device including a series of steps or modules (units) is not limited to the listed steps or modules (units), but may include unlisted steps or modules (units), or may include other steps or modules (units) inherent in these processes, methods, products or devices. The terms "connected", "coupled" and the like involved in the present application do not limit to physical or mechanical connections, but may include electrical connections, whether directly or indirectly. The term "plurality" involved in the present application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" may represent: A exists alone, A and B exist simultaneously, and B exists alone. Usually, the character " / " represents an "or" relationship between the associated objects before and after. The terms "first", "second", "third" and the like involved in the present application are only used to distinguish similar objects and do not represent a specific sorting of the objects.

[0051] Figure 1is a schematic diagram of a magnetic resonance imaging system according to some embodiments of this specification. As Figure 1 shown, the magnetic resonance imaging system 100 may include a scanning device 110 and an imaging device 120; the scanning device 100 is used to execute the following method embodiments; the imaging device 120 is used to perform imaging based on the scanning results to obtain a target magnetic resonance image. On this basis, it may further include a storage device 130, one or more terminals 140, and a network 150. The components in the magnetic resonance imaging system 100 may be connected in one or more of various ways. Only as an example, as Figure 1 shown, the scanning device 110 may be connected to the imaging device 120 through the network 150. As another example, the scanning device 110 may be directly connected to the imaging device 120, such as the scanning device 110 and the imaging device 120 may be connected as indicated by the dotted double-headed arrow. As yet another example, the storage device 130 may be directly connected to the imaging device 120 ( Figure 1 not shown in the figure) or connected through the network 150. As still another example, one or more terminals 140 may be directly connected to the imaging device 120 (as shown by the dotted double-headed arrow connecting the terminal 140 and the imaging device 120) or connected through the network 150.

[0052] The scanning device 110 may execute a magnetic resonance scanning method with variable shimming parameters in an embodiment to scan an object or a part thereof located in its detection area, and generate a magnetic resonance signal related to the object or the part thereof. In this application, the terms "object" and "subject" may be used interchangeably. In some embodiments, the object may include a body, a substance, etc., or any combination thereof. In some embodiments, the object may include a specific part of the body, such as the head, chest, abdomen, etc., or any combination thereof. In some embodiments, the object may include a specific organ, such as the heart, esophagus, trachea, bronchus, stomach, gallbladder, small intestine, colon, bladder, ureter, uterus, fallopian tube, etc.

[0053] The imaging device 120 may process data and / or information obtained and / or extracted from the scanning device 110, the terminal 140, the storage device 130, and / or other storage devices. For example, the imaging device 120 may obtain scanning data based on the scanning results, and reconstruct and generate a target magnetic resonance image based on the scanning data. In some embodiments, the generated magnetic resonance image may be sent to the terminal 140 and displayed on one or more display devices in the terminal 140.

[0054] The storage device 130 may store data and / or instructions. In some embodiments, the storage device 130 may store data obtained from the terminal 140 and / or the imaging device 120. In some embodiments, the storage device 130 may store data and / or instructions that the imaging device 120 may execute or use to perform the exemplary methods described in this application. In some embodiments, the storage device 130 may include a mass storage device, a removable storage device, a volatile read-write memory, a read-only memory (ROM), etc. or any combination thereof. Exemplary mass storage may include magnetic disks, optical disks, solid state drives, etc. Exemplary removable memory may include flash drives, floppy disks, optical disks, memory cards, compact disks, magnetic tapes, etc. Exemplary volatile read-write memory may include random access memory (RAM). Exemplary RAM may include dynamic random access memory (DRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), static random access memory (SRAM), thyristor random access memory (T-RAM), and zero-capacitor random access memory (Z-RAM), etc. Exemplary ROM may include mask ROM (MROM), programmable ROM (PROM), erasable programmable ROM (PEROM), electrically erasable programmable ROM (EEPROM), compact disk ROM (CD-ROM), and digital versatile disk ROM, etc. In some embodiments, the storage device 130 may be implemented on a cloud platform. By way of example only, the cloud platform may include a private cloud, a public cloud, a hybrid cloud, a community cloud, a distributed cloud, an internal cloud, a multi-layer cloud, etc. or any combination thereof.

[0055] The terminal 140 may include a mobile device 140-1, a tablet computer 140-2, a laptop computer 140-3, etc., or any combination thereof. In some embodiments, the mobile device 140-1 may include a smart home device, a wearable device, a smart mobile device, a virtual reality device, an augmented reality device, etc., or any combination thereof. In some embodiments, the smart home device may include a smart lighting device, a smart appliance control device, a smart monitoring device, a smart TV, a smart camera, an intercom, etc., or any combination thereof. In some embodiments, the wearable device may include a smart bracelet, smart shoelaces, smart glasses, a smart helmet, a smart watch, smart clothing, a smart backpack, smart accessories, etc., or any combination thereof. In some embodiments, the smart mobile device may include a smart phone, a personal digital assistant (PDA), a gaming device, a navigation device, a point of sale (POS), etc., or any combination thereof. In some embodiments, the virtual reality device and / or the augmented reality device may include a virtual reality helmet, virtual reality glasses, a virtual reality eye mask, an augmented reality helmet, augmented reality glasses, an augmented reality eye mask, etc., or any combination thereof. For example, the virtual reality device and / or the augmented reality device may include Google Glass, Oculus Rift, Hololens, Gear VR, etc.

[0056] Network 150 may include any suitable network that can facilitate the exchange of information and / or data of magnetic resonance imaging system 100. In some embodiments, one or more components of magnetic resonance imaging system 100 (e.g., scanning device 110, one or more terminals 140, imaging device 120, or storage device 130) may communicate with one or more other components of magnetic resonance imaging system 100 to transmit information and / or data. In some embodiments, network 150 may be any type of wired or wireless network or a combination thereof. Network 150 may be and / or include a public network (e.g., the Internet), a private network (e.g., local area network (LAN), wide area network (WAN), etc.), a wired network (e.g., Ethernet), a wireless network (e.g., 802.11 network, Wi-Fi network, etc.), a cellular network (e.g., long term evolution (LTE) network), a frame relay network, a virtual private network (“VPN”), a satellite network, a telephone network, routers, hubs, switches, server computers, and / or any combination thereof. By way of example only, network 150 may include a cable network, a wired network, an optical fiber network, a telecommunication network, an intranet, a wireless local area network (WLAN), a metropolitan area network (MAN), a public switched telephone network (PSTN), a BluetoothTM network, a ZigBeeTM network, a near field communication (NFC) network, etc., or any combination thereof. In some embodiments, network 150 may include one or more network access points. For example, network 150 may include wired and / or wireless network access points such as base stations and / or Internet exchange points, and one or more components of magnetic resonance imaging system 100 may be connected to network 150 through the wired and / or wireless access points to exchange data and / or information.

[0057] It should be noted that the above description of magnetic resonance imaging system 100 is for illustrative purposes only and is not intended to limit the scope of the present application. Various variations and modifications can be made by those of ordinary skill in the art according to the present application. However, these changes and modifications do not depart from the scope of the present application. For example, a display device may also be included in magnetic resonance imaging system 100 for outputting the scanned data, the finally generated target magnetic resonance image, etc.

[0058] In this embodiment, a magnetic resonance scanning method with variable shimming parameters is provided. Figure 2 is a flowchart of the magnetic resonance scanning method with variable shimming parameters in this embodiment, as Figure 2 shown, the process includes the following steps:

[0059] Step S210, before the sequence scan, based on the acquired localization image, determine the first shimming region and the second shimming region in the localization image;

[0060] Step S220, perform shimming on the first shimming region to obtain the first shimming parameter;

[0061] Step S230: Perform shimming on the second shimming region to obtain the second shimming parameter;

[0062] Step S240: During the execution of the sequence scan, repeatedly switch the first shimming parameter or the second shimming parameter to the corresponding working module, so that the preparation module in the working module uses the first shimming parameter to image the first shimming region, and the acquisition module in the working module uses the second shimming parameter to image the second shimming region.

[0063] Specifically, for the execution of the sequence scan, it can be divided into a preparation stage before the sequence scan and an execution stage during the sequence scan. In the preparation stage, mainly perform shimming on the first shimming region and the second shimming region in the localization image respectively to obtain the corresponding first shimming parameter and second shimming parameter. In the execution stage, the sequence scan images the first shimming region according to the first shimming parameter. Since the first shimming parameter matches the first shimming region, the imaging effect of the first shimming region can be guaranteed. The sequence scan images the second shimming region according to the second shimming parameter. Since the second shimming parameter matches the second shimming region, the imaging effect of the second shimming region can be guaranteed; thus solving the problem in the related art that the shimming method in a single shimming region under the same imaging sequence has a high shimming difficulty, resulting in low magnetic resonance imaging quality, and realizing switching the shimming parameter to the corresponding working module under the same imaging sequence to image the corresponding shimming region, thereby reducing the shimming difficulty and improving the magnetic resonance imaging quality.

[0064] Among them, the working module includes a preparation module and an acquisition module; the preparation module uses the first shimming parameter to image the first shimming region, and the acquisition module uses the second shimming parameter to image the second shimming region; these two will work alternately repeatedly to repeatedly switch the first shimming parameter or the second shimming parameter to the preparation module or the acquisition module of the corresponding working module until the sequence scan is completed.

[0065] Among them, in practical applications, the method for obtaining the localization image in the embodiments of the present application includes, but is not limited to, obtaining from a pre-stored database to obtain a localization image that meets the above requirements; it can also be downloading a localization image that meets the requirements from a network platform; it can also be describing the target region of the scanned object according to the requirements to generate a corresponding localization image, etc. The embodiments of the present application do not limit the method for obtaining the localization image. In this embodiment, in order to ensure the accuracy of the localization image, generally describe the target region of the scanned object according to the requirements to generate a corresponding localization image.

[0066] After obtaining the localization image, image processing, neural network models, etc. can be used to determine the first shimming region and the second shimming region in the localization image, so as to avoid the cavity and the tissue interface. Among them, for the shimming of the first shimming region and the second shimming region, the same or different shimming algorithms can be used (including but not limited to passive shimming algorithms, active shimming algorithms, or implemented according to the scanning device, etc.). For example: use the passive shimming algorithm to perform shimming on the first shimming region; use the active shimming algorithm to perform shimming on the second shimming region, etc. Examples are not given one by one here. Using different shimming algorithms can further ensure the accuracy of the shimming parameters.

[0067] Through the above steps, before the sequence scan, based on the acquired localization image, determine the first shimming region and the second shimming region in the localization image; perform shimming on the first shimming region to obtain the first shimming parameters; perform shimming on the second shimming region to obtain the second shimming parameters; during the execution of the sequence scan, repeatedly switch the first shimming parameters or the second shimming parameters to the corresponding working modules, so that the preparation module in the working module uses the first shimming parameters to image the first shimming region, and the acquisition module in the working module uses the second shimming parameters to image the second shimming region, solving the problem in the related technology that the shimming method of a single shimming region under the same imaging sequence has a high shimming difficulty, resulting in low magnetic resonance imaging quality, and realizing switching the shimming parameters to the corresponding working modules under the same imaging sequence to image the corresponding shimming regions, thereby reducing the shimming difficulty and improving the magnetic resonance imaging quality.

[0068] In some of these embodiments, performing shimming on the first shimming region in step S220 to obtain the first shimming parameters includes the following steps:

[0069] Step S221, perform main magnetic field B0 shimming on the first shimming region, and when the shimming result meets the main magnetic field B0 uniformity index of the full width at half maximum, obtain the first shimming parameters; the first shimming parameters include the first shimming coil compensation currents from zero order to high order.

[0070] Specifically, the process of shimming the first shimming region is as follows: perform a pre-scan of the main magnetic field B0 shimming on the first shimming region. After receiving the command for B0 shimming, the scanning device automatically executes a B0 shimming module sequence with a shimming algorithm to collect double echoes for imaging, obtaining a first double echo image. Take the difference in the phases of the first double echo image to obtain a first B0 field map, unwrap the first B0 field map, and use the shimming algorithm to fit the inhomogeneous terms of the first B0 field map, obtaining a third shimming parameter. It includes the first shimming coil compensation currents from zero order to high order. Determine whether the current value of the third shimming parameter meets the main magnetic field B0 uniformity index of the full width at half maximum (FWHM). When it meets the requirement, it is considered that the shimming of the first shimming region is completed, and the third shimming parameter is used as the first shimming parameter; the first shimming parameter includes the first shimming coil compensation currents from zero order to high order. If it does not meet the requirement, repeat the above process of shimming the first shimming region until it meets the requirement or reaches the number of cycles.

[0071] Through this embodiment, perform main magnetic field B0 shimming on the first shimming region. When the shimming result meets the main magnetic field B0 uniformity index of the full width at half maximum, obtain the first shimming parameter, thereby quickly and accurately obtaining the first shimming parameter corresponding to the first shimming region.

[0072] In some of these embodiments, the shimming of the second shimming region in step S230 to obtain the second shimming parameter includes:

[0073] Perform main magnetic field B0 shimming on the second shimming region. When the shimming result meets the main magnetic field B0 uniformity index of the full width at half maximum, obtain the second shimming parameter; the second shimming parameter includes the second shimming coil compensation currents from zero order to high order.

[0074] Specifically, the process of shimming the second shimming region is as follows: perform a pre-scan of the main magnetic field B0 shimming on the second shimming region. After receiving the command for B0 shimming, the scanning device automatically executes a B0 shimming module sequence with a shimming algorithm to collect double echoes for imaging, obtaining a second double echo image. Take the difference in the phases of the second double echo image to obtain a second B0 field map, unwrap the second B0 field map, and use the shimming algorithm to fit the inhomogeneous terms of the second B0 field map, obtaining a fourth shimming parameter. It includes the first shimming coil compensation currents from zero order to high order. Determine whether the current value of the fourth shimming parameter meets the main magnetic field B0 uniformity index of the full width at half maximum (FWHM). When it meets the requirement, it is considered that the shimming of the second shimming region is completed, and the fourth shimming parameter is used as the second shimming parameter; the second shimming parameter includes the second shimming coil compensation currents from zero order to high order. If it does not meet the requirement, repeat the above process of shimming the second shimming region until it meets the requirement or reaches the number of cycles.

[0075] In this embodiment, the main magnetic field B0 shimming is performed on the second shimming region. When the field homogenization result meets the main magnetic field B0 uniformity index of the full width at half maximum, the second shimming parameter is obtained, so as to quickly and accurately obtain the second shimming parameter corresponding to the second shimming region.

[0076] In other embodiments, the current value of the third shimming parameter can also be fed back to the terminal, and the user can determine whether the current value of the third shimming parameter meets the main magnetic field B0 uniformity index of the full width at half maximum; if it meets the requirement, in response to the user's operation, the third shimming parameter is saved as the first shimming parameter in the scanning device.

[0077] In some of these embodiments, as Figure 3 shown, the step of repeatedly switching the first shimming parameter or the second shimming parameter to the corresponding working module in step S240, so that the acquisition module in the working module uses the first shimming parameter to image the first shimming region and the acquisition module in the working module uses the second shimming parameter to image the second shimming region, includes the following steps:

[0078] Step S241, before the preparation module in the working module is executed, switch the first shimming parameter to the preparation module in the working module, so that the preparation module uses the first shimming parameter to image the first shimming region;

[0079] Step S242, before the acquisition module in the working module is executed, switch the second shimming parameter to the acquisition module in the working module, so that the acquisition module uses the second shimming parameter to image the second shimming region;

[0080] Step S243, repeatedly switch the first shimming parameter or the second shimming parameter to the corresponding working module until the sequence scan is completed.

[0081] Specifically, the sequence scan execution is completed by alternately executing the preparation module and the acquisition module in the working module. The first running module can be the preparation module or the acquisition module. In this embodiment, the preparation module is run first, then the acquisition module, and then the preparation module, thus alternately executing. Among them, the preparation module uses the first shimming parameter to image the first shimming region, and the acquisition module uses the second shimming parameter to image the second shimming region; during this alternating execution process, the first shimming parameter or the second shimming parameter is repeatedly switched to the corresponding working module until the sequence scan is completed.

[0082] In this embodiment, by repeatedly switching the first shimming parameter or the second shimming parameter to the corresponding working module until the sequence scan is completed, the imaging quality and the operation stability can be effectively improved.

[0083] Due to the alternating switching between the first shimming parameter and the second shimming parameter, it is necessary to convert the relevant shimming instructions (gradient control instructions) into digital signals, convert them into analog small signals through analog-to-digital conversion, and obtain a specific shimming current after power amplification to drive the shimming coil to compensate for the inhomogeneity of the B0 field. Therefore, a certain preparation time is required. Thus, according to the different available switching times, it is necessary to process the shimming parameters.

[0084] Specifically, for the first shimming parameter:

[0085] In some of these embodiments, the magnetic resonance scanning method with variable shimming parameters further includes the following steps:

[0086] After the preparation module in the working module is executed, it is judged whether the first available switching time meets the preset time threshold; the first available switching time is the available time for switching the first shimming parameter to the second shimming parameter;

[0087] When the first available switching time meets the preset time threshold, the compensation currents of the second shimming coils from zero order to high order are switched;

[0088] When the first available switching time does not meet the preset time threshold, the compensation currents of the zero-order and first-order second shimming coils are switched.

[0089] Specifically, the first available switching time refers to the available time for switching the first shimming parameter to the second shimming parameter after the preparation module is executed and before the acquisition module is executed. Also, because the corresponding shimming parameters need time to be processed, the switching of the relevant-order first shimming coil compensation currents in the second shimming coil compensation current will be determined according to the first available switching time. For example: when the first available switching time meets the preset time threshold, the compensation currents of the second shimming coils from zero order to high order are switched; when the first available switching time does not meet the preset time threshold, the compensation currents of the zero-order and first-order second shimming coils are switched.

[0090] In this embodiment, the preset time threshold can be based on the high-order term switching time. If the first available switching time is less than or equal to the high-order term switching time, it is considered that the compensation currents of the zero-order and first-order second shimming coils are switched. If the first available switching time is greater than the high-order term switching time, it is considered that the compensation currents of the second shimming coils from zero order to high order are switched. Of course, the preset time threshold can be determined according to the application scenario, and no limitation is imposed on this.

[0091] Through this embodiment, by judging whether the first available switching time meets the preset time threshold, different-order second shimming coil compensation currents are reasonably selected for switching, thereby improving the scanning efficiency while ensuring the imaging quality.

[0092] Specifically, for the second shimming parameter:

[0093] In some of these embodiments, the method for magnetic resonance scanning with variable shimming parameters further includes the following steps:

[0094] After the acquisition module in the working module is executed, it is judged whether the second available switching time meets a preset time threshold; the second available switching time is the available time for switching the second shimming parameter to the first shimming parameter;

[0095] When the second available switching time meets the preset time threshold, the compensation currents of the first shimming coils from zero order to high order are switched;

[0096] When the second available switching time does not meet the preset time threshold, the compensation currents of the zero-order and first-order first shimming coils are switched.

[0097] Specifically, the second available switching time refers to the available time for switching the second shimming parameter to the first shimming parameter after the preparation module is executed and before the acquisition module is executed. Also, because the corresponding shimming parameters need time to be processed, the switching of the relevant-order first shimming coil compensation currents in the first shimming coil compensation current will be determined according to the second available switching time. For example: when the second available switching time meets the preset time threshold, the compensation currents of the first shimming coils from zero order to high order are switched; when the second available switching time does not meet the preset time threshold, the compensation currents of the zero-order and first-order first shimming coils are switched.

[0098] In this embodiment, the preset time threshold can be based on the high-order term switching time. If the second available switching time is less than or equal to the high-order term switching time, it is considered that the compensation currents of the zero-order and first-order first shimming coils are switched. If the second available switching time is greater than the high-order term switching time, it is considered that the compensation currents of the first shimming coils from zero order to high order are switched. Of course, the preset time threshold can be determined according to the application scenario, and no limitation is imposed on this.

[0099] Through this embodiment, by judging whether the second available switching time meets the preset time threshold, different orders of the first shimming coil compensation currents are reasonably selected for switching, thereby improving the scanning efficiency while ensuring the imaging quality.

[0100] In other embodiments, for different sequences, different switching schemes (switching between the first shimming parameter and the second shimming parameter) can be specified. For example: for sequences with a shorter sequence preparation period, such as shorter than the high-order term switching time, the compensation currents of the zero-order and first-order shimming coils in the shimming parameters can be switched, while for sequences with a more sufficient preparation period, all the shimming coil compensation currents can be switched.

[0101] In some of these embodiments, the sequence is a perfusion sequence; when there is a first available switching time, the first available switching time is the Post Labeling Delay (PLD); or, when there is a second available switching time, the second available switching time is the Post Labeling Delay (PLD).

[0102] Among them, common magnetic resonance perfusion sequences, such as PASL, CASL, PCASL, etc., are all based on the inversion of the magnetization vector of arterial blood water to generate endogenous contrast agents.

[0103] The following is a description and illustration of this embodiment with a preferred embodiment of PCASL, where the first available switching time and the second available switching time are the post-labeling delay:

[0104] Such as Figure 4 、 Figure 5 and Figure 6 As shown, before the sequence scan, the scanned object acquires a localization image S10; based on the acquired localization image, the first shimming region A region S11 and the second shimming region B region S14 in the localization image are determined, as Figure 4 shown; pre-scan the B0 shimming of region A, and determine whether it meets the main magnetic field B0 uniformity index S12 of the full width at half maximum (FWHM); if not, return to S12; if it meets the requirements, record the first shimming parameter of region A into the spectrometer S13. Pre-scan the B0 shimming of region B, and determine whether it meets the main magnetic field B0 uniformity index S15 of the full width at half maximum (FWHM); if not, return to S14; if it meets the requirements, record the first shimming parameter of region A into the spectrometer S16; start the sequence scan S17; pre-switch to the first shimming parameter corresponding to region A S18.

[0105] The preparation module executes S19; determines whether the first available switching time (post-labeling delay) meets the preset time threshold S20; if it meets, switches to the zero-order and first-order of the second shimming parameter of region B S21; if it meets, switches to the zero-order to high-order of the second shimming parameter of region B S22; the acquisition module executes S23; determines whether the second available switching time (post-labeling delay) meets the preset time threshold S24; if it meets, switches to the zero-order and first-order of the first shimming parameter of region A S25; if it meets, switches to the zero-order to high-order of the first shimming parameter of region A S26; returns to S19 for sequence loop; the sequence scan ends S27.

[0106] The above embodiments are applicable to sequences that require switching of B0 shimming parameters, which can improve the B0 field uniformity during perfusion, thereby reducing the shimming difficulty and improving the magnetic resonance imaging quality.

[0107] It should be noted that the steps shown in the above process or the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. And although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0108] In this embodiment, a magnetic resonance scanning device with variable shimming parameters is also provided. This device is used to implement the above-mentioned embodiments and preferred implementation manners, and those that have been described will not be repeated here. The following terms such as "module", "unit", "sub-unit", etc. can be a combination of software and / or hardware that can achieve a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0109] Figure 7 is the structural block diagram of the magnetic resonance scanning device with variable shimming parameters of this embodiment, as Figure 7 shown, the device includes: a processing module 210, a first shimming module 220, a second shimming module 230, and an imaging module 240;

[0110] The processing module 210 is used to determine the first shimming region and the second shimming region in the positioning image based on the acquired positioning image before sequence scanning;

[0111] The first shimming module 220 is used to perform shimming on the first shimming region to obtain the first shimming parameter;

[0112] The second shimming module 230 is used to perform shimming on the second shimming region to obtain the second shimming parameter;

[0113] The imaging module 240 is used to repeatedly switch the first shimming parameter or the second shimming parameter to the corresponding working module during sequence scanning execution, so that the preparation module in the working module uses the first shimming parameter to image the first shimming region, and the acquisition module in the working module uses the second shimming parameter to image the second shimming region.

[0114] Through the above device, the problem that in the related art, the shimming method in a single shimming region under the same imaging sequence has a high shimming difficulty, resulting in low magnetic resonance imaging quality is solved. It realizes switching the shimming parameter to the corresponding working module under the same imaging sequence to image the corresponding shimming region, thereby reducing the shimming difficulty and improving the magnetic resonance imaging quality.

[0115] In some of these embodiments, the imaging module 240 is further used to switch the first shimming parameter to the preparation module in the working module before the preparation module in the working module is executed, so that the preparation module uses the first shimming parameter to image the first shimming region;

[0116] Before the acquisition module in the working module is executed, when switching the second shimming parameter to the acquisition module in the working module, the acquisition module uses the second shimming parameter to image the second shimming region;

[0117] Repeat switching the first shimming parameter or the second shimming parameter to the corresponding working module until the sequence scan is completed.

[0118] In some of these embodiments, the imaging module 240 is further configured to, after the preparation module in the working module is executed, determine whether a first available switching time meets a preset time threshold; the first available switching time is the available time for switching the first shimming parameter to the second shimming parameter;

[0119] When the first available switching time meets the preset time threshold, switch the compensation currents of the second shimming coils from zero order to high order;

[0120] When the first available switching time does not meet the preset time threshold, switch the compensation currents of the zero-order and first-order second shimming coils.

[0121] In some of these embodiments, the imaging module 240 is further configured to, after the acquisition module in the working module is executed, determine whether a second available switching time meets a preset time threshold; the second available switching time is the available time for switching the second shimming parameter to the first shimming parameter;

[0122] When the second available switching time meets the preset time threshold, switch the compensation currents of the first shimming coils from zero order to high order;

[0123] When the second available switching time does not meet the preset time threshold, switch the compensation currents of the zero-order and first-order first shimming coils.

[0124] In some of these embodiments, the sequence is a perfusion sequence;

[0125] When there is a first available switching time, the first available switching time is a labeled post-extension period;

[0126] Or, when there is a second available switching time, the second available switching time is a labeled post-extension period.

[0127] In some of these embodiments, the first shimming module 220 is further configured to perform main magnetic field B0 shimming on the first shimming region, and obtain a first shimming parameter when the shimming result meets the main magnetic field B0 uniformity index of the full width at half maximum; the first shimming parameter includes the compensation currents of the first shimming coils from zero order to high order.

[0128] In some of these embodiments, the second shimming module 230 is further configured to perform B0 shimming on the second shimming region, and obtain second shimming parameters when the field homogenization result meets the B0 uniformity index of the full width at half maximum; the second shimming parameters include the second shimming coil compensation currents from zero order to high order.

[0129] It should be noted that the above-mentioned respective modules may be functional modules or program modules, and can be implemented either by software or by hardware. For the modules implemented by hardware, the above-mentioned respective modules may be located in the same processor; or the above-mentioned respective modules may also be located in different processors in any combined form.

[0130] In this embodiment, a computer device is further provided, including a memory and a processor. A computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0131] Optionally, the above computer device may further include a transmission device and input / output devices. Among them, the transmission device is connected to the above processor, and the input / output devices are connected to the above processor.

[0132] Optionally, in this embodiment, the above processor may be configured to execute the following steps through a computer program:

[0133] S1. Before the sequence scan, based on the acquired localization image, determine the first shimming region and the second shimming region in the localization image;

[0134] S2. Perform shimming on the first shimming region to obtain first shimming parameters;

[0135] S3. Perform shimming on the second shimming region to obtain second shimming parameters;

[0136] S4. During the execution of the sequence scan, repeatedly switch the first shimming parameters or the second shimming parameters to the corresponding working modules, so that the preparation module in the working module uses the first shimming parameters to image the first shimming region, and the acquisition module in the working module uses the second shimming parameters to image the second shimming region.

[0137] It should be noted that specific examples in this embodiment may refer to the examples described in the above embodiments and optional implementation manners, and will not be elaborated in this embodiment.

[0138] In addition, in combination with the magnetic resonance scanning method with variable shimming parameters provided in the above embodiments, a storage medium may also be provided to implement it in this embodiment. A computer program is stored on the storage medium; when the computer program is executed by a processor, it implements any one of the above-mentioned magnetic resonance scanning methods with variable shimming parameters.

[0139] It should be understood that the specific embodiments described herein are only used to explain this application and not to limit it. All other embodiments obtained by those of ordinary skill in the art without creative work according to the embodiments provided in this application fall within the protection scope of this application.

[0140] Obviously, the accompanying drawings are only some examples or embodiments of this application. For those of ordinary skill in the art, this application can also be applied to other similar situations based on these drawings without creative work. Additionally, it can be understood that although the work done during this development process may be complex and time-consuming, for those of ordinary skill in the art, certain design, manufacturing, or production changes based on the technical content disclosed in this application are only routine technical means and should not be regarded as insufficient disclosure of this application.

[0141] The term "embodiment" in this application means that the specific features, structures, or characteristics described in connection with the embodiments may be included in at least one embodiment of this application. The phrase appears in various positions in the specification and does not necessarily mean the same embodiment, nor does it mean being independent or alternative to other embodiments and mutually exclusive. Those of ordinary skill in the art can clearly or implicitly understand that the embodiments described in this application can be combined with other embodiments without conflict.

[0142] The above-described embodiments only represent several implementation manners of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of patent protection. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several modifications and improvements can still be made, and these all belong to the protection scope of this application. Therefore, the protection scope of this application shall be subject to the appended claims.

Claims

1. A magnetic resonance scanning method with variable shimming parameters, characterized in that, the method includes: Before sequence scanning, based on the acquired localization image, determine the first shimming region and the second shimming region in the localization image; Perform shimming on the first shimming region to obtain the first shimming parameter; Perform shimming on the second shimming region to obtain the second shimming parameter; During sequence scanning execution, repeatedly switch the first shimming parameter or the second shimming parameter to the corresponding working module, so that the preparation module in the working module uses the first shimming parameter to image the first shimming region, and the acquisition module in the working module uses the second shimming parameter to image the second shimming region.

2. The magnetic resonance scanning method with variable shimming parameters according to claim 1, characterized in that, Repeatedly switching the first shimming parameter or the second shimming parameter to the corresponding working module, so that the preparation module in the working module uses the first shimming parameter to image the first shimming region, and the acquisition module in the working module uses the second shimming parameter to image the second shimming region, includes: Before the preparation module in the working module executes, switch the first shimming parameter to the preparation module in the working module, so that the preparation module uses the first shimming parameter to image the first shimming region; Before the acquisition module in the working module executes, switch the second shimming parameter to the acquisition module in the working module, so that the acquisition module uses the second shimming parameter to image the second shimming region; Repeatedly switch the first shimming parameter or the second shimming parameter to the corresponding working module until the sequence scanning is completed.

3. The magnetic resonance scanning method with variable shimming parameters according to claim 2, characterized in that, the method further includes: After the preparation module in the working module executes, determine whether the first available switching time meets the preset time threshold; the first available switching time is the available time for switching the first shimming parameter to the second shimming parameter; When the first available switching time meets the preset time threshold, switch the compensation current of the second shimming coil from zero order to high order; When the first available switching time does not meet the preset time threshold, switch the compensation current of the zero order and the first order of the second shimming coil.

4. The magnetic resonance scanning method with variable shimming parameters according to claim 2, characterized in that, the method further includes: After the acquisition module in the working module executes, determine whether the second available switching time meets the preset time threshold; the second available switching time is the available time for switching the second shimming parameter to the first shimming parameter; When the second available switching time meets the preset time threshold, switch the compensation current of the first shimming coil from zero order to high order; When the second available switching time does not meet the preset time threshold, switch the compensation current of the zero order and the first order of the first shimming coil.

5. The magnetic resonance scanning method with variable shimming parameters according to any one of claims 3 or 4, characterized in that, The sequence is a perfusion sequence; When having the first available switching time, the first available switching time is a marker delay period; Or, when having the second available switching time, the second available switching time is a marker delay period.

6. The magnetic resonance scanning method with variable shimming parameters according to claim 1, characterized in that shimming the first shimming region to obtain first shimming parameters, including: shimming the main magnetic field B0 of the first shimming region, and obtaining the first shimming parameters when the field homogenization result meets the main magnetic field B0 uniformity index of the full width at half maximum; the first shimming parameters include the first shimming coil compensation currents from zero order to high order.

7. The magnetic resonance scanning method with variable shimming parameters according to claim 1, characterized in that shimming the second shimming region to obtain second shimming parameters, including: shimming the main magnetic field B0 of the second shimming region, and obtaining the second shimming parameters when the field homogenization result meets the main magnetic field B0 uniformity index of the full width at half maximum; the second shimming parameters include the second shimming coil compensation currents from zero order to high order.

8. A magnetic resonance scanning device with variable shimming parameters, characterized in that it includes: a processing module, a first shimming module, a second shimming module and an imaging module; the processing module is configured to determine the first shimming region and the second shimming region in the positioning image based on the acquired positioning image before sequence scanning; the first shimming module is configured to shim the first shimming region to obtain first shimming parameters; the second shimming module is configured to shim the second shimming region to obtain second shimming parameters; the imaging module is configured to repeatedly switch the first shimming parameters or the second shimming parameters to the corresponding working modules during sequence scanning execution, so that the preparation module in the working module uses the first shimming parameters to image the first shimming region, and the acquisition module in the working module uses the second shimming parameters to image the second shimming region.

9. A computer device, including a memory and a processor, characterized in that a computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps of the magnetic resonance scanning method with variable shimming parameters according to any one of claims 1 to 7.

10. A magnetic resonance imaging system, characterized in that it includes: a scanning device and an imaging device; wherein, the scanning device is connected to the imaging device; the scanning device is configured to execute the magnetic resonance scanning method with variable shimming parameters according to any one of claims 1 to 7; the imaging device is configured to perform imaging based on the scanning result to obtain a target magnetic resonance image.

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