Magnetic resonance imaging method, apparatus, device, and medium

Abstract

Embodiments of the present application disclose a magnetic resonance imaging method, device, equipment and medium. The method determines layer motion information and in-layer motion information of a scanning object, corrects layer motion and in-layer motion respectively, determines a target imaging layer of the scanning object through the layer motion information, excites the target imaging layer, corrects the layer motion in the acquisition process, corrects the magnetic resonance signal of the target imaging layer based on the in-layer motion information, and obtains a target image of the scanning object, so as to correct the in-layer motion in the reconstruction process. The method applies the layer motion information and the in-layer motion information to the acquisition and reconstruction processes respectively, avoids the problem that the layer cannot be accurately corrected in the retrospective motion correction, improves the accuracy of the motion correction in the magnetic resonance imaging, and reduces the complexity of the correction while obtaining the accurate correction result, thereby improving the efficiency of the motion correction.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of magnetic resonance, and particularly relate to a magnetic resonance imaging method, device, equipment and medium. BACKGROUND

[0002] Magnetic resonance imaging has advantages of high spatial resolution, superior soft tissue contrast, no ionizing radiation, etc., and is a very important means in the field of clinical medical auxiliary diagnosis. However, compared with other technologies (such as computed tomography), the magnetic resonance imaging method has a longer scanning time, and the scanning time of one part is usually more than ten minutes. It is very difficult for a patient (especially a patient with a particularly strong pain) to remain motionless during the scanning process. Therefore, various motion artifacts can often be seen in the magnetic resonance image, and the existence of the motion artifacts seriously affects the image quality so that a doctor cannot make a diagnosis.

[0003] Currently, the motion correction methods commonly used for rigid structures such as the head mainly include two categories. One is retrospective motion correction, that is, after the data is collected, the motion information is used to correct in the reconstruction process, such as spiral acquisition. The other is prospective motion correction, that is, during the acquisition process, the motion information is used to adjust the sequence (gradient direction, etc.) in real time, and finally the corrected data is collected. However, the retrospective motion correction has a problem that the layer cannot be accurately corrected, and the prospective motion correction has a high requirement for the sequence and is complex to operate. SUMMARY

[0004] Embodiments of the present application provide a magnetic resonance imaging method, device, equipment and medium to improve the accuracy of motion correction in magnetic resonance imaging and reduce the complexity of motion correction.

[0005] In a first aspect, embodiments of the present application provide a magnetic resonance imaging method, and the method comprises:

[0006] determining layer motion information and intra-layer motion information of a scanning object;

[0007] determining a target imaging layer of the scanning object based on the layer motion information, and exciting the target imaging layer by using an imaging sequence;

[0008] acquiring a magnetic resonance signal corresponding to the target imaging layer, correcting the magnetic resonance signal based on the intra-layer motion information, and determining a target image of the scanning object based on a correction result.

[0009] Optionally, the determination of the layer motion information of the scanning object comprises:

[0010] acquiring navigation data of the scanning object, wherein the navigation data is acquired by an external device or obtained by exciting the scanning object by using a navigation sequence.

[0011] determining slice direction motion information based on the navigation data;

[0012] determining slice motion information of the scan object based on the slice direction motion information.

[0013] Optionally, the determining the intra-slice motion information of the scan object comprises:

[0014] determining phase encoding direction motion information and frequency encoding direction motion information based on the navigation data, and determining the intra-slice motion information of the scan object based on the phase encoding direction motion information and the frequency encoding direction motion information; or

[0015] determining the intra-slice motion information of the scan object based on historical magnetic resonance images of the scan object.

[0016] Optionally, the determining the slice motion information of the scan object based on the slice direction motion information comprises:

[0017] determining conversion data of the navigation data in a logical coordinate system or a patient coordinate system;

[0018] determining the slice motion information of the scan object based on slice direction motion information of the conversion data.

[0019] Optionally, the determining the target imaging slice of the scan object based on the slice motion information comprises:

[0020] determining an initial imaging slice of the scan object before the imaging sequence is triggered;

[0021] determining a position of the target imaging slice corresponding to the initial imaging slice based on the slice motion information.

[0022] Optionally, the triggering the target imaging slice using the imaging sequence comprises:

[0023] determining a slice gradient direction and / or a slice pulse frequency in the imaging sequence based on the target imaging slice;

[0024] triggering the target imaging slice based on the slice gradient direction and / or the slice pulse frequency.

[0025] Optionally, the correcting the magnetic resonance signal based on the intra-slice motion information comprises:

[0026] determining encoding displacement information based on the intra-slice motion information, wherein the encoding displacement information comprises at least one of a phase encoding direction translation, a phase encoding direction rotation, a frequency encoding direction translation and a frequency encoding direction rotation.

[0027] performing rotation processing and / or translation processing on the magnetic resonance signals in the K-space domain and / or the magnetic resonance signals in the image domain based on the encoded displacement information.

[0028] In a second aspect, an embodiment of the present application further provides a magnetic resonance imaging device, the device comprising:

[0029] an information determining module configured to determine layer motion information and intra-layer motion information of a scanning object;

[0030] an imaging triggering module configured to determine a target imaging layer of the scanning object based on the layer motion information, and trigger the target imaging layer using an imaging sequence;

[0031] an image reconstructing module configured to acquire magnetic resonance signals corresponding to the target imaging layer, correct the magnetic resonance signals based on the intra-layer motion information, and determine a target image of the scanning object based on a correction result.

[0032] In a third aspect, an embodiment of the present application further provides an electronic device, the electronic device comprising:

[0033] one or more processors;

[0034] a storage configured to store one or more programs,

[0035] when the one or more programs are executed by the one or more processors, the one or more processors implement the magnetic resonance imaging method provided by any of the embodiments of the present application.

[0036] In a fourth aspect, an embodiment of the present application further provides a computer readable storage medium, which stores a computer program, and the program is executed by a processor to implement the magnetic resonance imaging method provided by any of the embodiments of the present application.

[0037] The embodiments of the above application have the following advantages or beneficial effects:

[0038] By determining the slice motion information and the in-slice motion information of the scanning object, the slice motion and the in-slice motion are corrected respectively, and then the target imaging slice of the scanning object is determined by the slice motion information, the target imaging slice is excited by the imaging sequence to realize the correction of the slice motion in the acquisition process, and the magnetic resonance signal of the target imaging slice is corrected based on the in-slice motion information to obtain the target image of the scanning object, so as to realize the correction of the in-slice motion in the reconstruction process. The method applies the slice motion information and the in-slice motion information to the acquisition and reconstruction processes respectively, can avoid the problem that the slice motion cannot be accurately corrected in the retrospective motion correction, improves the accuracy of the motion correction in the magnetic resonance imaging, and then improves the accuracy of the magnetic resonance imaging. Furthermore, for the sequence with high requirement on the system hardware or the sequence not sensitive to the in-slice motion, the method can obtain accurate correction results while reducing the complexity of the correction, and then improves the efficiency of the motion correction, and further improves the efficiency of the magnetic resonance imaging. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the example embodiments of the present application, the drawings needed in the description of the embodiments are briefly introduced as follows. Obviously, the drawings introduced are only a part of the drawings of the embodiments described by the present application, and not all the drawings. Those skilled in the art can obtain other drawings according to these drawings without creating labor.

[0040] Figure 1 A flowchart of a magnetic resonance imaging method provided by the first embodiment of the present application is shown in the figure.

[0041] Figure 2 A flowchart of a magnetic resonance imaging method provided by the second embodiment of the present application is shown in the figure.

[0042] Figure 3A A structure diagram of a magnetic resonance imaging device provided by the third embodiment of the present application is shown in the figure.

[0043] Figure 3B An initial imaging slice provided by the third embodiment of the present application is shown in the figure.

[0044] Figure 3C A target imaging slice provided by the third embodiment of the present application is shown in the figure.

[0045] Figure 3D An imaging sequence provided by the third embodiment of the present application is shown in the figure.

[0046] Figure 3E An adjusted imaging sequence provided by the third embodiment of the present application is shown in the figure.

[0047] Figure 4A structural schematic diagram of an electronic device provided in Embodiment Four of the present application. DETAILED DESCRIPTION

[0048] The present application will be further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are intended to be merely illustrative of the present application and not in limitation thereof. It should also be noted that, for the purpose of description, only the parts related to the present application are shown in the drawings rather than all the parts.

[0049] Embodiment One

[0050] Figure 1 A flowchart of a magnetic resonance imaging method provided in Embodiment One of the present application. This embodiment can be applied to the case where motion artifacts are corrected in a magnetic resonance imaging process. The method can be executed by a magnetic resonance imaging correction device, which can be implemented by hardware and / or software. The method specifically includes the following steps:

[0051] S110, determining layer motion information and in-layer motion information of a scanning object.

[0052] The layer motion information can be the rotation and / or translation of the scanning object in the selected layer direction, i.e., the rotation and / or translation of the imaging layer of the scanning object. The in-layer motion information can be the rotation and / or translation of the scanning object in the encoding direction. Specifically, the motion of the scanning object can cause the imaging layer position to change, and the positions of the voxels in the imaging layer to change.

[0053] Optionally, the navigation data can be obtained by an external device or by exciting the scanning object through a navigation sequence. In this embodiment, the layer motion information and the in-layer motion information of the scanning object can be determined based on the navigation data. The navigation data includes hardware navigation or software navigation data. The hardware navigation includes, but is not limited to, millimeter wave, infrared, optical camera, etc. The software navigation includes, but is not limited to, self-data navigation, breathing navigation sequence, etc. Specifically, the 6-degree-of-freedom motion information of the scanning object can be obtained based on the navigation data, and then the layer motion information and the in-layer motion information can be separated from the 6-degree-of-freedom motion information. The coordinate system of the 6-degree-of-freedom motion information is not limited in the present application, which can be a physical coordinate system, a logical coordinate system, or a patient coordinate system. For example, the navigation data in this embodiment can be imported by an external device or an external application program. After the navigation data is imported, it can be stored locally to facilitate the extraction of the navigation data when the motion of the scanning object is corrected.

[0054] In another embodiment, the in-scan motion information of the scan object can also be determined based on the magnetic resonance signal scanned at the previous time. In other words, the in-scan motion information can be obtained from the navigator data or the magnetic resonance signal scanned at the previous time.

[0055] S120, determining a target imaging slice of the scan object based on the slice motion information, and exciting the target imaging slice by using the imaging sequence.

[0056] In the embodiment, the imaging slice position to be imaged changes due to the motion of the scan object, and thus the target imaging slice needs to be determined again based on the slice motion information so as to excite the target imaging slice for imaging. Specifically, a new slice selection direction can be determined based on the slice motion information, and then the target imaging slice can be determined based on the new slice selection direction.

[0057] For example, the determination of the target imaging slice based on the slice motion information includes: determining an initial imaging slice of the scan object before the imaging sequence is excited, wherein the initial imaging slice is a predicted imaging slice, such as a slice selected by a technician or a slice required to be imaged by a user; and determining a position of the target imaging slice corresponding to the initial imaging slice based on the slice motion information. In this embodiment, the target imaging slice contains the same voxels as the initial imaging slice, but due to the motion, the target imaging slice and the initial imaging slice have a displacement or difference in coordinate position. The displacement or difference in coordinate position can be corrected based on the slice motion information.

[0058] Specifically, the initial imaging slice can be moved based on the slice motion information to obtain the target imaging slice. It should be noted that the imaging positions of the initial imaging slice before the movement and the target imaging slice determined after the movement are always the same set of voxel positions. Through this optional embodiment, the target imaging slice of the scan object can be accurately determined, and the slice motion correction of the magnetic resonance imaging is realized, and the accuracy of the magnetic resonance imaging is improved.

[0059] Further, after the target imaging slice is determined, the parameters of the imaging sequence can be updated or adjusted, and the target imaging slice can be excited by using the adjusted imaging sequence to obtain the magnetic resonance signal corresponding to the target imaging slice. For example, the target imaging slice can be excited by changing the slice selection pulse, or the target imaging slice can be excited by changing the slice selection gradient.

[0060] In an optional embodiment, the exciting the target imaging slice by using the imaging sequence can be: determining a slice selection gradient direction and / or a slice selection pulse frequency in the imaging sequence based on the target imaging slice; and exciting the target imaging slice based on the slice selection gradient direction and / or the slice selection pulse frequency. That is, the target imaging slice can be excited by changing the direction of the slice selection gradient and / or the frequency of the slice selection pulse in the imaging sequence to image the target imaging slice. This optional embodiment realizes accurate excitation of the target imaging slice, and thus realizes slice motion correction of magnetic resonance imaging, and solves the technical problem that slice motion cannot be accurately corrected in the prior art.

[0061] S130, acquiring a magnetic resonance signal corresponding to the target imaging slice, correcting the magnetic resonance signal based on the intra-slice motion information, and determining a target image of the scanning object based on a result of the correction.

[0062] Specifically, after the target imaging slice is excited, a magnetic resonance signal corresponding to the target imaging slice can be received by a radio frequency receiving coil to reconstruct a magnetic resonance image based on the magnetic resonance signal. In this embodiment, the magnetic resonance signal can be corrected by the intra-slice motion information during the reconstruction of the magnetic resonance signal, and then a target image of the scanning object is determined based on a result of the correction. In this embodiment, the intra-slice motion information can be represented by two quantities, i.e., a translation of a center position and a rotation around the center. If the intra-slice motion information is determined based on a magnetic resonance image at a previous time (i.e., a historical magnetic resonance image), the intra-slice motion information can be stored locally, and each motion occurrence time and each intra-slice motion information are stored correspondingly.

[0063] For example, the initial position of an intra-slice voxel in the target imaging slice before the motion of the scanning object is A, and the position changes to B after the rotation θ and the translation m (intra-slice motion information). After the magnetic resonance signal is acquired, the position B of the intra-slice voxel in the magnetic resonance signal can be restored to the position A by the rotation -θ and the translation -m.

[0064] Optionally, the correcting the magnetic resonance signal based on the intra-slice motion information comprises: determining encoding displacement information based on the intra-slice motion information, wherein the encoding displacement information comprises at least one of a phase encoding direction translation amount, a phase encoding direction rotation amount, a frequency encoding direction translation amount, and a frequency encoding direction rotation amount; and performing rotation processing and / or translation processing on the magnetic resonance signal in a K-space domain and / or the magnetic resonance signal in an image domain based on the encoding displacement information.

[0065] The in-layer motion information can be divided into motion in the phase encoding direction and motion in the frequency encoding direction, and each of the motions in the directions can be represented by a translational amount and / or a rotational amount, and thus at least one of a phase encoding direction translational amount, a phase encoding direction rotational amount, a frequency encoding direction translational amount, and a frequency encoding direction rotational amount can be determined based on the in-layer motion information.

[0066] It should be noted that the in-layer motion information can include only motion in the phase encoding direction, or only motion in the frequency encoding direction, or both motion in the phase encoding direction and motion in the frequency encoding direction, and the motion in the phase or frequency encoding direction can also be divided into rotation, translation, and rotation+translation, and thus the encoding displacement information can be one or more combinations of the phase encoding direction translational amount, the phase encoding direction rotational amount, the frequency encoding direction translational amount, and the frequency encoding direction rotational amount.

[0067] Further, after the encoding displacement information is determined, the magnetic resonance signal can be rotated and / or translated in the K-space domain, or the magnetic resonance signal can be rotated and / or translated in the image domain, or part of the magnetic resonance signal can be rotated and / or translated in the K-space domain and the remaining part of the magnetic resonance signal can be rotated and / or translated in the image domain. That is, the in-layer motion correction can be performed in the K-space domain, in the image domain, or partially in the K-space domain and partially in the image domain.

[0068] Specifically, the rotation and / or translation of the magnetic resonance signal in the K-space domain or the image domain based on the encoding displacement information can be: determining at least one of a phase encoding direction inverse translational amount, a phase encoding direction inverse rotational amount, a frequency encoding direction inverse translational amount, and a frequency encoding direction inverse rotational amount based on at least one of the phase encoding direction translational amount, the phase encoding direction rotational amount, the frequency encoding direction translational amount, and the frequency encoding direction rotational amount; and performing rotation and / or translation of the magnetic resonance signal in the K-space domain or the image domain based on at least one of the phase encoding direction inverse translational amount, the phase encoding direction inverse rotational amount, the frequency encoding direction inverse translational amount, and the frequency encoding direction inverse rotational amount. Through this optional embodiment, the in-layer motion correction of the magnetic resonance imaging is realized, and the technical problems of low accuracy and high complexity in the prior art for correcting the in-layer motion of the part sequence which is not sensitive to the in-layer motion are solved.

[0069] The technical scheme of the embodiment determines the layer motion information and the in-layer motion information of the scanning object, corrects the layer motion and the in-layer motion respectively, determines the target imaging layer of the scanning object through the layer motion information, excites the target imaging layer, corrects the layer motion in the acquisition process, corrects the magnetic resonance signal of the target imaging layer based on the in-layer motion information, and obtains the target image of the scanning object, so as to correct the in-layer motion in the reconstruction process. The method applies the layer motion information and the in-layer motion information to the acquisition and reconstruction processes respectively, can avoid the problem that the layer motion cannot be accurately corrected in the retrospective motion correction, improves the accuracy of the motion correction in the magnetic resonance imaging, and further improves the accuracy of the magnetic resonance imaging. In addition, for the sequence with high requirements on system hardware or the sequence not sensitive to in-layer motion, the method can obtain accurate correction results while reducing the complexity of correction, and further improve the efficiency of motion correction, and further improve the efficiency of magnetic resonance imaging.

[0070] Embodiment two

[0071] Figure 2 A flowchart of a magnetic resonance imaging method provided by the second embodiment of the application is provided. Based on the above-mentioned embodiments, the layer motion information of the scanning object is determined, including: obtaining navigation data of the scanning object, wherein the navigation data is obtained by an external device or by a navigation sequence; determining the layer direction motion information based on the navigation data; and determining the layer motion information of the scanning object based on the layer direction motion information. Optionally, the in-layer motion information of the scanning object is determined, including: determining the phase encoding direction motion information and the frequency encoding direction motion information based on the navigation data; determining the in-layer motion information of the scanning object based on the phase encoding direction motion information and the frequency encoding direction motion information; or determining the in-layer motion information of the scanning object based on the historical magnetic resonance image of the scanning object. The explanations of the same or corresponding terms in the above-mentioned embodiments are not repeated here. See Figure 2 The magnetic resonance imaging correction provided by the embodiment includes the following steps:

[0072] S210, determining navigation data of a scanning object.

[0073] The navigation data is obtained by an external device or by a navigation sequence, and the navigation data includes layer direction motion information, phase encoding direction motion information, and frequency encoding direction motion information.

[0074] Specifically, the slice selection direction motion information includes slice selection direction translation information and slice selection direction rotation information; the phase encoding direction motion information includes phase encoding direction translation information and phase encoding direction rotation information; and the frequency encoding direction motion information includes frequency encoding direction translation information and frequency encoding direction rotation information.

[0075] In S220, slice selection direction motion information is determined based on the navigation data, and slice level motion information of the scanning object is determined based on the slice selection direction motion information.

[0076] In the embodiment, the slice selection direction motion information in the physical coordinate system, the logical coordinate system or the patient coordinate system in the navigation data can be determined as the slice level motion information. The slice selection direction motion information in the patient coordinate system can be obtained by conversion from the slice selection direction motion information in the physical coordinate system, and the slice selection direction motion information in the logical coordinate system can be obtained by conversion from the slice selection direction motion information in the patient coordinate system.

[0077] For example, the slice level motion information of the scanning object is determined based on the slice selection direction motion information, including: determining conversion data of the navigation data in the logical coordinate system or the patient coordinate system; and determining the slice level motion information of the scanning object based on the slice selection direction motion information of the conversion data.

[0078] In the embodiment, the six degrees of freedom information in the navigation data can be motion information in the physical coordinate system. In the embodiment, the navigation data in the physical coordinate system can be converted to obtain conversion data in the patient coordinate system, and the slice selection direction motion information in the conversion data can be determined as the slice level motion information of the scanning object. Alternatively, the navigation data in the physical coordinate system can be converted to obtain conversion data in the patient coordinate system, and the conversion data in the patient coordinate system can be further converted to obtain conversion data in the logical coordinate system, and the slice selection direction motion information in the conversion data in the logical coordinate system can be determined as the slice level motion information of the scanning object.

[0079] In S230, phase encoding direction motion information and frequency encoding direction motion information are determined based on the navigation data, and slice level motion information of the scanning object is determined based on the phase encoding direction motion information and the frequency encoding direction motion information; or the slice level motion information of the scanning object is determined based on historical magnetic resonance images of the scanning object.

[0080] That is, the phase encoding direction motion information and the frequency encoding direction motion information in the navigation data can be obtained, and the phase encoding direction motion information and the frequency encoding direction motion information can be determined as the slice level motion information of the scanning object; or the slice level motion information of the scanning object can be determined based on historical magnetic resonance images of the scanning object, such as the magnetic resonance image at the previous time.

[0081] The in-layer motion information determined based on the phase-encoding direction motion information and the frequency-encoding direction motion information can be phase-encoding direction motion information, frequency-encoding direction motion information in a patient coordinate system, a physical coordinate system or a logical coordinate system.

[0082] For example, the navigation data containing 6 degrees of freedom information in the physical coordinate system can be converted to the logical coordinate system, in which the rotation and translation in the slice direction are taken as the slice motion information, and the rotation and translation in the phase-encoding direction and the frequency-encoding direction are taken as the in-layer motion information, in which only one rotation is needed; or the navigation data containing 6 degrees of freedom information in the physical coordinate system can be converted to the patient coordinate system, in which the rotation and translation in the slice direction are taken as the slice motion information, and the rotation and translation in the phase-encoding direction and the frequency-encoding direction are taken as the in-layer motion information, in which only one rotation is needed; or the navigation data containing 6 degrees of freedom information in the physical coordinate system can be converted to the patient coordinate system, in which the rotation and translation in the slice direction are taken as the slice motion information, and the navigation data in the patient coordinate system is then converted to the logical coordinate system, in which the rotation and translation in the phase-encoding direction and the frequency-encoding direction are taken as the in-layer motion information, in which only one rotation is needed.

[0083] In S240, a target imaging slice of the scanning object is determined based on the slice motion information, and the target imaging slice is excited by using an imaging sequence.

[0084] In S250, a magnetic resonance signal corresponding to the target imaging slice is acquired, the magnetic resonance signal is corrected based on the in-layer motion information, and a target image of the scanning object is determined based on the correction result.

[0085] For example, for an EPI (Echo Planar Imaging) sequence, the slice selection gradient direction and the radio frequency pulse frequency phase can be modified after the target imaging slice is determined and before the target imaging slice is excited, so as to excite the target imaging slice, and after the magnetic resonance signal of the target imaging slice is acquired, the in-layer image is rotated and translated according to the in-layer motion information. For a spiral acquisition sequence, the slice direction can be corrected before each arm starts, and after the acquisition is completed, each arm is reconstructed, and in the reconstruction process, the motion can be corrected according to the in-layer motion information (determined by the navigation data or a magnetic resonance image at a certain historical moment). For a single shot type sequence, the slice direction motion can be corrected before each excitation of the target imaging slice, and after the acquisition is completed, the motion can be corrected according to the in-layer motion information in the reconstruction process. For a multiple shot type sequence, the slice direction motion can be corrected at each imaging, and after the acquisition is completed, the motion can be corrected according to the in-layer motion information in the reconstruction process.

[0086] The technical scheme of the embodiment determines the layer motion information of the scanning object through the layer selection direction motion information in the navigation data, and further determines the target imaging layer of the scanning object based on the layer motion information and excites the target imaging layer, thereby realizing motion correction in the layer direction in magnetic resonance imaging and solving the technical problem that the layer cannot be accurately corrected in retrospective motion correction.

[0087] Embodiment three

[0088] Figure 3A A structural schematic diagram of a magnetic resonance imaging device provided for the third embodiment of the application. The embodiment can be applied to the case where motion artifacts are corrected in the magnetic resonance imaging process. The device specifically comprises an information determination module 310, an imaging excitation module 320, and an image reconstruction module 330.

[0089] The information determination module 310 is configured to determine the layer motion information and the intra-layer motion information of the scanning object.

[0090] The imaging excitation module 320 is configured to determine the target imaging layer of the scanning object based on the layer motion information and excite the target imaging layer using an imaging sequence.

[0091] The image reconstruction module 330 is configured to acquire the magnetic resonance signal corresponding to the target imaging layer, correct the magnetic resonance signal based on the intra-layer motion information, and determine the target image of the scanning object based on the correction result.

[0092] Optionally, the information determination module 310 comprises a first determination unit configured to acquire the navigation data of the scanning object, determine the layer selection direction motion information based on the navigation data, and determine the layer motion information of the scanning object based on the layer selection direction motion information. The navigation data is acquired by an external device or the scanning object is excited by a navigation sequence.

[0093] Optionally, the information determination module 310 further comprises a second determination unit configured to determine the phase encoding direction motion information and the frequency encoding direction motion information based on the navigation data, determine the intra-layer motion information of the scanning object based on the phase encoding direction motion information and the frequency encoding direction motion information, or determine the intra-layer motion information of the scanning object based on the historical magnetic resonance image of the scanning object.

[0094] Optionally, the first determination unit is specifically configured to determine the conversion data of the navigation data in a logical coordinate system or a patient coordinate system, and determine the layer motion information of the scanning object based on the layer selection direction motion information of the conversion data.

[0095] Optionally, the imaging triggering module 320 comprises a layer determination unit, configured to determine an initial imaging layer of the scan object before triggering the imaging sequence; and determine a position of a target imaging layer corresponding to the initial imaging layer based on the layer motion information.

[0096] Optionally, the imaging triggering module 320 comprises a triggering unit, configured to determine a layer selection gradient direction and / or a layer selection pulse frequency of the imaging sequence based on the target imaging layer; and trigger the target imaging layer based on the layer selection gradient direction and / or the layer selection pulse frequency.

[0097] Optionally, the image reconstruction module 330 comprises an intra-layer correction unit, configured to determine encoding displacement information based on the intra-layer motion information, wherein the encoding displacement information comprises at least one of a phase encoding direction translation amount, a phase encoding direction rotation amount, a frequency encoding direction translation amount and a frequency encoding direction rotation amount; and perform rotation processing and / or translation processing on the magnetic resonance signal in the K-space domain and / or the magnetic resonance signal in the image domain based on the encoding displacement information.

[0098] In the embodiment, the layer motion information and the intra-layer motion information of the scan object are determined by the information determination module, so as to correct the layer motion and the intra-layer motion respectively, and then the target imaging layer of the scan object is determined based on the layer motion information by the imaging triggering module, and the target imaging layer is triggered, so as to correct the layer motion in the acquisition process, and the magnetic resonance signal of the target imaging layer is corrected based on the intra-layer motion information by the image reconstruction module, so as to obtain the target image of the scan object, so as to correct the intra-layer motion information in the reconstruction process. The method applies the layer motion information and the intra-layer motion information to the acquisition and the reconstruction process respectively, so as to avoid the problem that the layer motion cannot be corrected accurately in the retrospective motion correction, improve the accuracy of the motion correction in the magnetic resonance imaging, and for the sequence with high requirement on the system hardware or the sequence not sensitive to the intra-layer motion, the method can obtain the accurate correction result while reducing the complexity of the correction, so as to improve the efficiency of the motion correction.

[0099] In an embodiment of the present application, the scan object is taken as the head as an example, and the head motion of the scan object exists in the scanning process. As shown in FIG. 1, the head motion of the scan object in the scanning process is shown in FIG. 1. Figure 3BThe diagram shows the initial imaging plane, where the physical Z-axis corresponds to the frequency encoding direction (FE) on the logical axis, and the physical Y-axis corresponds to the phase encoding direction (PE) on the logical axis. The dashed box in the diagram represents the selected FOV region. During the scanning process, the imaging area contained within the FOV region will change due to head movement. The information determination module 310 can determine the plane motion information of the scanned object, and the imaging excitation module 320 can re-determine the target imaging plane based on the plane motion information. Specifically, as shown... Figure 3C The diagram shows the target imaging plane. The parameters of the imaging sequence are adjusted so that the imaging area contained in the FOV region (the area enclosed by the dashed line in the figure) remains unchanged.

[0100] like Figure 3D To and Figure 3B The corresponding imaging sequence diagram shows that the logical axis and physical axis are aligned at the initial moment. The waveform of the RF axis represents the timing of the application of radio frequency pulses; Gx represents the timing of the gradient pulses applied along the X-axis gradient, which in this embodiment corresponds to the timing of the gradient pulses along the layer selection gradient direction included in the imaging sequence; GY represents the timing of the gradient pulses applied along the Y-axis gradient, which in this embodiment corresponds to the timing of the gradient pulses along the phase encoding gradient direction included in the imaging sequence; and Gz represents the timing of the gradient pulses applied along the Z-axis gradient, which in this embodiment corresponds to the timing of the gradient pulses along the frequency encoding gradient direction included in the imaging sequence.

[0101] like Figure 3E To and Figure 3C The corresponding adjusted imaging sequence diagram shows that the logical axis and physical axis are offset due to motion. The waveform on the RF axis represents the timing of the applied radio frequency pulses, such as 90°, 180°, and 180° RF pulses; Gx represents the timing of the gradient pulses applied along the X-axis; GY represents the timing of the gradient pulses applied along the Y-axis; and Gz represents the timing of the gradient pulses applied along the Z-axis. To ensure consistency between the initial imaging layer within the FOV and the target imaging layer within the FOV, the gradient parameters of the imaging sequence are adjusted. In this embodiment, the gradient pulse timings in the GY and Gz gradient directions are adjusted respectively to change the gradient parameters of the phase encoding direction and the frequency encoding direction (readout direction). For example, phase encoding gradients or frequency encoding gradients are applied simultaneously in both gradient axis directions to change the phase encoding direction or the frequency encoding direction. Optionally, the zero-order moment of the phase encoding gradient can remain consistent / equal before and after the imaging sequence adjustment. Similarly, the zero-order moment of the frequency encoding gradient also remains consistent / equal before and after the imaging sequence adjustment.

[0102] In this specific embodiment, the pulses 321, 322 of the phase encoding gradient are applied simultaneously in both gradient directions Gy, Gz, and the zeroth order separation of both pulses 321, 322 of the phase encoding gradient is equal to the zeroth order separation of the pulse 311 of the phase encoding gradient. Furthermore, the pulses 323, 324 of the frequency encoding gradient are applied simultaneously in both gradient directions Gy, Gz, and the zeroth order separation of both pulses 323, 324 of the frequency encoding gradient is equal to the zeroth order separation of the pulse 312 of the frequency encoding gradient. Further, the pulses 325, 326 of the spoiler gradient are applied simultaneously in both gradient directions Gy, Gz, and the zeroth order separation of both pulses 325, 326 of the spoiler gradient is equal to the zeroth order separation of the pulse 313 of the spoiler gradient.

[0103] The magnetic resonance imaging apparatus provided by the embodiments of the present application can perform the magnetic resonance imaging method provided by any of the embodiments of the present application, and has the corresponding function modules and beneficial effects of performing the method.

[0104] It is worth noting that the units and modules included in the above system are only divided according to the functional logic, and are not limited to the above division, as long as the corresponding functions can be realized; in addition, the specific names of each functional unit are only for easy mutual differentiation, and are not used to limit the protection scope of the embodiments of the present application.

[0105] Embodiment Four

[0106] Figure 4 is a structural schematic diagram of an electronic device provided by Embodiment Four of the present application. Figure 4 A block diagram of an exemplary electronic device 12 suitable for implementing an embodiment of the present application is shown. Figure 4 The electronic device 12 shown is merely an example and should not be taken as limiting the functionality or applicability of embodiments of the present application. The device 12 is typically an electronic device that performs magnetic resonance imaging.

[0107] As shown in Figure 4 The electronic device 12 is shown in the form of a general purpose computing device. The components of electronic device 12 can include, but are not limited to, one or more processors or processing units 16, a memory 28, a bus 18 that connects the various components (including the memory 28 and the processing unit 16).

[0108] Bus 18 represents one or more of several bus architectures, including a memory bus or memory controller, a peripheral bus, a graphics acceleration port, a processor, or a local bus using any of the various bus architectures. Examples of these architectures include, but are not limited to, the Industry Standard Architecture (ISA) bus, the Micro Channel Architecture (MCA) bus, the Enhanced ISA bus, the Video Electronics Standards Association (VESA) local bus, and the Peripheral Component Interconnect (PCI) bus.

[0109] Electronic device 12 typically includes a variety of computer-readable media. These media can be any available media that can be accessed by electronic device 12, including volatile and non-volatile media, removable and non-removable media.

[0110] Memory 28 may include computer device readable media in the form of volatile memory, such as random access memory (RAM) 30 and / or cache memory 32. Electronic device 12 may further include other removable / non-removable, volatile / non-volatile computer storage media. By way of example only, storage device 34 may be used to read and write non-removable, non-volatile magnetic media (…). Figure 4 Not shown; usually referred to as a "hard drive"). Although Figure 4 Not shown, disk drives for reading and writing to removable non-volatile disks (e.g., "floppy disks") and optical disc drives for reading and writing to removable non-volatile optical discs (e.g., Compact Disc-Read Only Memory (CD-ROM), Digital Video Disc-Read Only Memory (DVD-ROM), or other optical media) may be provided. In these cases, each drive may be connected to bus 18 via one or more data media interfaces. Memory 28 may include at least one program product 40 having a set of program modules 42 configured to perform the functions of the embodiments of the present invention. Program product 40 may be stored, for example, in memory 28. Such program modules 42 include, but are not limited to, one or more application programs, other program modules, and program data, each or some combination of these examples may include an implementation of a network environment. Program modules 42 typically perform the functions and / or methods described in the embodiments of the present invention.

[0111] The electronic device 12 can also be in communication with one or more external devices 14 such as a keyboard, a mouse, camera, etc., and a display. Additionally, the electronic device 12 can communicate with one or more devices that enable a user to interact with the electronic device 12 and / or any devices (e.g., a network card, a modem, etc.) that enable the electronic device 12 to communicate with one or more other computing devices. Such communication can occur via an input / output (I / O) interface 22. Still yet, the electronic device 12 can communicate with one or more networks (such as a Local Area Network (LAN), a Wide Area Network (WAN), and / or the Internet) through a network adapter 20. As depicted, the network adapter 20 communicates with the other components of the electronic device 12 via the bus 18. It should be appreciated that the electronic device 12 can be a part of another device or be a stand-alone device. In addition, the electronic device 12 can be connected to one or more devices in series, parallel, or some combination thereof. It is to be further understood that, although a particular number of components of the electronic device 12 are depicted, any number of components can be used.

[0112] The processor 16 performs various functions through running programs stored in the memory 28, such as implementing the magnetic resonance imaging method provided by the above embodiments of the present application, including:

[0113] determining layer motion information and in-layer motion information of a scanning object;

[0114] determining a target imaging layer of the scanning object based on the layer motion information, and exciting the target imaging layer;

[0115] determining a magnetic resonance signal corresponding to the target imaging layer, correcting the magnetic resonance signal based on the in-layer motion information, and determining a target image of the scanning object based on a result of the correction.

[0116] Of course, those skilled in the art can understand that the processor can also implement the technical solutions of the magnetic resonance imaging method provided by any of the embodiments of the present application.

[0117] Embodiment five

[0118] The embodiment five of the present application also provides a computer readable storage medium, which stores a computer program, and the program is executed by a processor to implement the steps of the magnetic resonance imaging method provided by any of the embodiments of the present application, and the method includes:

[0119] determining layer motion information and in-layer motion information of a scanning object;

[0120] determine a target imaging slice of the scanning object based on the slice motion information, and excite the target imaging slice;

[0121] determine a magnetic resonance signal corresponding to the target imaging slice, correct the magnetic resonance signal based on the intra-slice motion information, and determine a target image of the scanning object based on a result of the correction.

[0122] The computer storage medium of the embodiments of the present application can adopt any combination of one or more computer readable media. The computer readable medium can be a computer readable signal medium or a computer readable storage medium. The computer readable storage medium may, for example, be, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or apparatus, or any combination of the above. More specific examples (non-exhaustive list) of the computer readable storage medium include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this document, the computer readable storage medium can be any tangible medium that contains or stores a program that can be used by or in connection with an instruction execution system, apparatus or device.

[0123] The computer readable signal medium can include a data signal propagated in a baseband or as a part of a carrier wave, in which a computer readable program code is carried. Such a propagated data signal can take multiple forms, including but not limited to an electromagnetic signal, an optical signal or any suitable combination of the above. The computer readable signal medium can also be any computer readable medium that is not a computer readable storage medium and that can transmit, propagate or transport a program for use by or in connection with an instruction execution system, apparatus or device.

[0124] The program code contained on the computer readable medium can be transmitted in any suitable medium, including but not limited to wireless, wire, cable, optical fiber, RF, etc., or any suitable combination of the above.

[0125] Computer program code for carrying out operations of embodiments of the present application can be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like, and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0126] It is to be understood that the above description is directed to the preferred embodiments and that those skilled in the art will be able to devise various modifications which, although not specifically described herein, embody the principles of the application and are included within the spirit and scope of the application. Accordingly, while the preferred embodiments have been described above, those skilled in the art will understand that they are not to be limited to the preferred embodiments, but are to include all such embodiments falling within the scope of the application as defined by the appended claims.

Claims

1. A magnetic resonance imaging method, characterized by, The method comprises: determining the layer motion information and the in-layer motion information of the scanning object; wherein the layer motion information is the rotation and / or translation of the scanning object in the selected layer direction; and the in-layer motion information is the rotation and / or translation of the scanning object in the encoding direction; determining the target imaging layer of the scanning object based on the layer motion information, and exciting the target imaging layer by using an imaging sequence; acquiring the magnetic resonance signal corresponding to the target imaging layer, correcting the magnetic resonance signal based on the in-layer motion information, and determining the target image of the scanning object based on the correction result; wherein the determination of the target imaging layer of the scanning object based on the layer motion information comprises: determining the initial imaging layer of the scanning object before the excitation of the imaging sequence; determining the position of the target imaging layer corresponding to the initial imaging layer based on the layer motion information; the correction of the magnetic resonance signal based on the in-layer motion information comprises: determining the encoding displacement information based on the in-layer motion information, wherein the encoding displacement information comprises at least one of the phase encoding direction translation, the phase encoding direction rotation, the frequency encoding direction translation, and the frequency encoding direction rotation; performing rotation processing and / or translation processing on the magnetic resonance signal in the K-space domain and / or the magnetic resonance signal in the image domain based on the encoding displacement information.

2. The method of claim 1, wherein, The determination of the layer motion information of the scanning object comprises: acquiring the navigation data of the scanning object, wherein the navigation data is acquired by an external device or by exciting the scanning object by using a navigation sequence; determining the selected layer direction motion information based on the navigation data; determining the layer motion information of the scanning object based on the selected layer direction motion information.

3. The method of claim 2, wherein, The determination of the in-layer motion information of the scanning object comprises: determining the phase encoding direction motion information and the frequency encoding direction motion information based on the navigation data, and determining the in-layer motion information of the scanning object based on the phase encoding direction motion information and the frequency encoding direction motion information; or determining the in-layer motion information of the scanning object based on the historical magnetic resonance image of the scanning object.

4. The method of claim 2, wherein, The determination of the layer motion information of the scanning object based on the selected layer direction motion information comprises: determining the conversion data of the navigation data in a logical coordinate system or a patient coordinate system; determining the layer motion information of the scanning object based on the selected layer direction motion information of the conversion data.

5. The method of claim 1, wherein, The excitation of the target imaging layer by using the imaging sequence comprises: determining the selected layer gradient direction and / or the selected layer pulse frequency in the imaging sequence based on the target imaging layer; exciting the target imaging layer based on the selected layer gradient direction and / or the selected layer pulse frequency.

6. A magnetic resonance imaging apparatus, characterized by The device comprises: an information determination module configured to determine the layer motion information and the in-layer motion information of the scanning object; wherein the layer motion information is the rotation and / or translation of the scanning object in the selected layer direction; and the in-layer motion information is the rotation and / or translation of the scanning object in the encoding direction. An imaging excitation module configured to determine a target imaging slice of the scan object based on the slice motion information, and excite the target imaging slice with an imaging sequence; An image reconstruction module configured to acquire magnetic resonance signals corresponding to the target imaging slice, correct the magnetic resonance signals based on the intra-slice motion information, and determine a target image of the scan object based on a result of the correction; The imaging excitation module comprises: A slice determination unit configured to determine an initial imaging slice of the scan object before the imaging sequence is excited, and determine a position of the target imaging slice corresponding to the initial imaging slice based on the slice motion information. The image reconstruction module comprises: An intra-slice correction unit configured to determine encoding displacement information based on the intra-slice motion information, wherein the encoding displacement information comprises at least one of a phase-encoding direction translation, a phase-encoding direction rotation, a frequency-encoding direction translation, and a frequency-encoding direction rotation, and perform rotation processing and / or translation processing on the magnetic resonance signals in a K-space domain and / or the magnetic resonance signals in an image domain based on the encoding displacement information.

7. An electronic device, comprising: The electronic device comprises: One or more processors; A storage device configured to store one or more programs, When the one or more programs are executed by the one or more processors, the one or more processors implement the magnetic resonance imaging method according to any one of claims 1-5.

8. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to implement the magnetic resonance imaging method according to any one of claims 1-5.

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