Magnetic resonance imaging apparatus and magnetic resonance imaging method

Abstract

To improve image quality.SOLUTION: A magnetic resonance imaging device is a magnetic resonance imaging device for imaging an examination part of a subject, and includes a collection unit, a correction unit, and an image generation unit. The collection unit continuously collects a navigation echo signal and an imaging signal from the examination part in a plurality of times of shots respectively. The correction unit calculates an amount of movement of the subject by using a plurality of k spaces generated on the basis of the navigation echo signal in the plurality of times of shots respectively, and corrects an imaging k space generated on the basis of the imaging signal in the plurality of times of shots. The image generation unit generates an image of the examination part by using the imaging k space after correction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The embodiments disclosed in this specification and the drawings relate to a magnetic resonance imaging apparatus and a magnetic resonance imaging method. [Background technology]

[0002] In magnetic resonance imaging (MRI), a single scan takes several minutes to several tens of minutes, and patient movement during the scan can appear in the image as motion artifacts. One method for suppressing motion artifacts is to collect data at high speed. For example, there is a sequence that uses SSFP (Steady-State Free Precession). Another method for suppressing motion artifacts is motion correction. Furthermore, in 3D FSE (Fast Spin Echo) sequences, a VFA (Variable Flip Angle) may be used to generally reduce blurring, improve tissue contrast, and reduce SAR (Specific Absorption Rate). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP2014-161566Publication Summary of the Invention [Problem to be solved by the invention]

[0004] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to improve image quality. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described below can also be positioned as other problems. [Means for solving the problem]

[0005] A magnetic resonance imaging apparatus according to an embodiment is a magnetic resonance imaging apparatus for imaging an examination region of a subject, and includes an acquisition unit, a correction unit, and an image generation unit. The acquisition unit continuously acquires navi-echo signals and imaging signals from the examination region in multiple shots. The correction unit calculates a movement amount of the subject using multiple k-spaces generated based on the navi-echo signals in the multiple shots, and corrects the imaging k-spaces generated based on the imaging signals in the multiple shots. The image generation unit generates an image of the examination region using the corrected imaging k-space. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a magnetic resonance imaging apparatus according to an embodiment. [Figure 2] FIG. 2 is a diagram showing an example of a pulse sequence of the magnetic resonance imaging apparatus according to the embodiment. [Figure 3] FIG. 3 is a diagram showing an example of a method for constructing a spherical k-space in the embodiment. [Figure 4] FIG. 4 is a diagram showing an example of a method for three-dimensionally imaging an examination region of a subject. [Figure 5] FIG. 5 is a diagram showing an example of a pulse sequence of a magnetic resonance imaging apparatus according to the prior art. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments of a magnetic resonance imaging apparatus and a magnetic resonance imaging method will be described in detail with reference to the drawings.

[0008] A magnetic resonance imaging apparatus 1 of the present invention will be described below with reference to Figs. 1 to 4. Fig. 1 is a structural block diagram of the magnetic resonance imaging apparatus 1. Each component of the magnetic resonance imaging apparatus 1 will be described below. The static magnetic field magnet 10 generates a static magnetic field in an imaging space in which a subject is placed. For example, the static magnetic field magnet 10 is formed of a superconducting magnet, a permanent magnet, or the like.

[0009] The gradient magnetic field coil 20 generates a gradient magnetic field. For example, the gradient magnetic field coil has an X coil, a Y coil, and a Z coil corresponding to the X axis, Y axis, and Z axis, which are orthogonal to each other. The X coil, Y coil, and Z coil generate gradient magnetic fields along each axial direction by current supplied from the gradient magnetic field power supply 30. Here, the Z axis is set along the magnetic flux of the static magnetic field generated by the static magnetic field magnet 10. The X axis is set along the horizontal direction orthogonal to the Z axis. The Y axis is set along a direction orthogonal to both the Z axis and the X axis.

[0010] The gradient magnetic field power supply 30 supplies a current to the gradient magnetic field coil 20. When the gradient magnetic field power supply 30 supplies a current to the gradient magnetic field coil 20, the gradient magnetic field coil 20 can generate a gradient magnetic field.

[0011] The RF (Radio Frequency) coil 40 applies a high-frequency magnetic field to a subject placed in the imaging space and receives NMR (Nuclear Magnetic Resonance) signals generated from the subject. The high-frequency magnetic field is sometimes called an RF pulse. The RF coil 40 includes a whole-body RF coil 41 placed so as to surround the imaging space and a local RF coil 42 placed close to the subject. The functions of the RF coil 40 are broadly divided into transmitting a high-frequency magnetic field and receiving an NMR signal. Either the whole-body RF coil 41 or the local RF coil 42 may have both transmitting and receiving functions, or both the whole-body RF coil 41 and the local RF coil 42 may be used for transmitting and receiving. Furthermore, multiple local RF coils 42 may be used simultaneously. Different local RF coils 42 may be provided for different parts of the subject.

[0012] The transmission circuit 50 outputs to the RF coil 40 a radio frequency pulse signal corresponding to the Larmor frequency specific to the target atomic nucleus placed in the static magnetic field.

[0013] The receiving circuitry 60 generates magnetic resonance (MR) data based on the NMR signals received by the RF coil 40, and outputs the generated MR data to the processing circuitry 100. The bed 70 includes a top board 71 on which the subject is placed, and the top board 71 can be moved vertically and horizontally.

[0014] The input interface 80 accepts input operations of various instructions and information from an operator. Specifically, the input interface 80 is connected to the processing circuit 100, converts the input operations received from the operator into electrical signals, and outputs the electrical signals to the processing circuit 100. For example, the input interface 80 may be realized by a trackball, a switch button, a mouse, a keyboard, a touchpad that performs input operations by touching the operation surface, a touchscreen that integrates a display screen and a touchpad, a non-contact input circuit using an optical sensor, and a voice input circuit. Note that in this specification, the input interface 80 is not limited to those that include physical operation components such as a mouse and a keyboard. For example, an electrical signal processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the device and outputs the electrical signal to a control circuit is also included as an example of the input interface 80.

[0015] The display 81 displays various types of information and images. Specifically, the display 81 is connected to the processing circuit 100, and converts the data of various types of information and images sent from the processing circuit 100 into electrical signals for display and outputs the signals. For example, the display 81 is realized by a liquid crystal monitor, an LED monitor, a touch panel, or the like.

[0016] The memory circuitry 90 stores various data and programs. Specifically, the memory circuitry 90 is connected to the processing circuitry 100 and stores various data and programs input and output by each processing circuit. For example, the memory circuitry 90 is realized by a semiconductor memory element such as a RAM (Random Access Memory) or a flash memory, a hard disk, an optical disk, or the like.

[0017] The processing circuit 100 has a bed control function 101. The bed control function 101 controls the operation of the bed 70 by outputting a control electrical signal to the bed 70. For example, the bed control function 101 receives an instruction to move the top 71 from an operator via the input interface 80, and operates a moving mechanism of the top 71 of the bed 70 so as to move the top 71 in accordance with the received instruction. For example, when imaging the subject, the bed control function 101 moves the top 71, on which the subject is placed, into an imaging space.

[0018] The processing circuitry 100 includes an acquisition function 102. The acquisition function 102 executes various pulse sequences to acquire MR data of a subject. Specifically, the acquisition function 102 executes various pulse sequences by driving the gradient magnetic field power supply 30, the transmission circuitry 50, and the reception circuitry 60 in accordance with sequence execution data output from the processing circuitry 100. Here, the sequence execution data is data representing a pulse sequence, and is information that specifies the timing and strength of the current when the gradient magnetic field power supply 30 supplies a current to the gradient magnetic field coil 20, the timing and strength of the high-frequency pulse when the transmission circuitry 50 supplies a high-frequency pulse signal to the RF coil 40, and the timing when the reception circuitry 60 samples a magnetic resonance signal. The sequence execution data is pre-stored in the storage circuitry 90 or is generated by receiving an input from an operator via the input interface 80. Alternatively, the operator may edit the sequence execution data pre-stored in the storage circuitry 90. The acquisition function 102 then receives the MR data output from the reception circuitry 60 as a result of executing the pulse sequence and stores it in the storage circuitry 90. At this time, the MR data stored in the memory circuitry 90 is stored as k-space data. For example, when performing two-dimensional imaging, a phase encoding gradient magnetic field is applied to a slice plane selected by the slice selection gradient magnetic field. The k-space data of the phase encoding amount according to the applied gradient magnetic field is read out using a readout gradient magnetic field. The readout gradient magnetic field is also called a frequency encoding gradient magnetic field. For example, when performing three-dimensional imaging, a slice encoding gradient magnetic field and a phase encoding gradient magnetic field are applied, and the k-space data of the encoding amount according to the applied gradient magnetic field is read out using a readout gradient magnetic field. The slice selection gradient magnetic field, phase encoding gradient magnetic field, readout gradient magnetic field, and slice encoding gradient magnetic field described above are each formed by gradient magnetic fields generated by one or more of the X coil, Y coil, and Z coil described above.

[0019] The processing circuit 100 includes a correction function 103. The correction function 103 uses at least a part of the k-space data acquired by the acquisition function 102 to perform correction to suppress motion artifacts caused by movement of the subject.

[0020] The processing circuit 100 has an image generation function 104. The image generation function 104 generates various images based on the k-space data acquired by the acquisition function 102. For example, an MR image is generated by performing a reconstruction process such as a Fourier transform on the k-space data. Although the following description uses an imaging k-space in a Cartesian coordinate system as an example, imaging k-space in other coordinate systems can also be used. The image generation function 104 can also perform image processing on the reconstructed image as post-processing.

[0021] The processing circuit 100 has a display control function 105. The display control function 105 outputs the image generated by the image generation function 104 to the display 81. It is also possible to acquire an image stored in the memory circuit 90 or an external storage and display it on the display 81.

[0022] The processing circuits 100 described above are each realized by a processor. In this case, the processing functions of each processing circuit are stored in the storage circuitry 90, for example, in the form of a program executable by a computer. Each processing circuit then reads out each program from the storage circuitry 90 and executes it to realize the processing function corresponding to each program. In other words, after reading out each program, each processing circuit has the functions shown in each processing circuit in FIG. 1.

[0023] Although each processing circuit has been described herein as being implemented by a single processor, the embodiment is not limited thereto. Each processing circuit may be configured by combining multiple independent processors, and each processor may execute a program to implement each processing function. Furthermore, the processing functions of each processing circuit may be appropriately distributed or integrated among a single or multiple processing circuits. Furthermore, in the example shown in FIG. 1, a single storage circuit 90 is described as storing a program corresponding to each processing function. However, multiple storage circuits may be distributed and arranged, and each processing circuit may read the corresponding program from each storage circuit. The collection function, correction function, image generation function, and display control function are examples of a collection unit, a correction unit, an image generation unit, and a display unit, respectively.

[0024] Fig. 2 is a diagram showing an example of a pulse sequence included in sequence execution data executed by the acquisition function 102. Fig. 2 shows a 3D FLAIR (Three-Dimensional Fluid Attenuated Inversion Recovery) sequence.

[0025] In FIG. 2, RF indicates a radio frequency (RF) pulse. PE indicates a gradient magnetic field pulse in the phase encoding gradient direction, SE indicates a gradient magnetic field pulse in the slice encoding gradient direction, RO indicates a gradient magnetic field pulse in the frequency encoding gradient direction, and ADC indicates the timing for receiving and digitizing an MR signal as an analog signal. In one shot, an inversion recovery (IR) pulse is applied first, followed by an excitation pulse EP, followed by pulse application in a stabilization stage S1 and an imaging stage S2. Here, "one shot" refers to the application of one excitation pulse EP. The IR pulse is applied, for example, to suppress water signals.

[0026] For example, typically, navi-echo signals N are not acquired in the stabilization step S1. Even if navi-echo signals N are acquired, they are not used to generate images. In contrast, in the present invention, the signals acquired in the stabilization step S1 are used to correct the signals acquired in the imaging step S2. That is, the processing circuit 100 uses the acquisition function 102 to acquire navi-echo signals N in the stabilization step S1, which stabilizes the subsequent imaging signal (imaging echo signal E).

[0027] In the stabilization step S1, gradient magnetic field pulses in three different gradient directions, for example, PE, SE, and RO, are applied to acquire navi-echo signals N that can construct a spherical k-space sks shown in FIG. 3, which will be described later, and one piece of spherical k-space data is constructed based on the navi-echo signals N acquired in a single shot. The navi-echo signals N include multiple data points. In the stabilization step S1, for example, a VFA RF pulse is used.

[0028] In the imaging step S2, as shown in Fig. 2, a gradient magnetic field pulse different from the gradient magnetic field pulse applied in the stabilization step S1 is applied to acquire an imaging echo signal E, and one piece of imaging k-space data is constructed based on the imaging echo signal E acquired in one shot. The imaging echo signal E includes a plurality of data points.

[0029] 2, in one shot, the stabilization stage S1 and the imaging stage S2 are consecutive. That is, after acquiring the navigation echo signal N, the imaging echo signal E is immediately acquired. That is, the processing circuit 100 uses the acquisition function 102 to successively acquire the navigation echo signal and the imaging signal from the examination region in each of the multiple shots.

[0030] The correction of the imaging k-space data by the correction function 103 will be described below with reference to FIGS.

[0031] FIG. 3 is a diagram showing a method for constructing a spherical k-space sks according to an example of the present invention, and FIG. 4 is a diagram showing a method for three-dimensionally imaging an examination region of a subject according to the present invention.

[0032] When inspecting an inspection area of ​​a subject, data of the inspection area is usually collected by multiple shots, as shown in Fig. 3. Fig. 3 shows n shots, namely, shot 1 to shot n.

[0033] Each shot acquires multiple navi-echo signals. For example, shot 1 includes multiple navi-echo signals: a first signal nav1, a second signal nav2, a third signal nav3, a fourth signal nav4, a fifth signal nav5, ... an m-th signal navm (m is a natural number greater than or equal to 6). Each navi-echo signal includes multiple data points and corresponds to each point in the spherical k-space sks. Although an example of acquiring the first signal nav1 to the m-th signal navm (m is a natural number greater than or equal to 6) is given, the number of acquired navi-echo signals is not particularly limited and may be less than six.

[0034] In shot 1, when constructing a spherical k-space sks using multiple navi-echo signals, a single spherical k-space sks is constructed by spirally arranging these points on the sphere in the following order: one point in the first signal nav1, one point in the second signal nav2, one point in the third signal nav3, one point in the fourth signal nav4, one point in the fifth signal nav5, ... one point in the m-th signal navm, another point in the first signal nav1, another point in the second signal nav2, another point in the third signal nav3, another point in the fourth signal nav4, another point in the fifth signal nav5, ... another point in the m-th signal navm. In other words, the spherical k-space sks is constructed so that the points in each navi-echo signal are alternately arranged. Similarly, in shots 2 through n, a single spherical k-space sks is constructed, similar to shot 1.

[0035] That is, the processing circuitry 100 acquires a plurality of navi-echo signals for each shot using the acquisition function 102, and each of the navi-echo signals consists of a plurality of data points. Furthermore, the spherical k-space generated based on these navi-echo signals is constructed so that the data points in the navi-echo signals are arranged alternately.

[0036] Normally, there is a gap of several seconds between each shot, but considering that the examination region of the subject may have moved after this gap time has elapsed, the imaging k-space portion (not shown) constructed by two adjacent shots is corrected based on the amount of movement between the spherical k-spaces sks constructed for each of the two adjacent shots. That is, the processing circuitry 100 uses the correction function 103 to calculate the amount of movement of the subject using multiple spherical k-spaces generated based on the navi-echo signals for multiple shots, and corrects the imaging k-space generated based on the imaging signals for the multiple shots.

[0037] As an example, if the multiple shots include a first shot and a second shot, the processing circuit 100 corrects the imaging k-space constructed by the second shot using the correction function 103 based on the amount of movement of the spherical k-space constructed by the second shot relative to the spherical k-space constructed by the first shot.

[0038] An example of imaging with shot 1 and shot 2 will be described. In shot 1, a first spherical k-space is constructed using multiple navi echo signals N (including the first signal nav1 to the mth signal navm), and a first imaging k-space portion is constructed using multiple imaging echo signals E (including signals E1, E2, E3, E4, E5, ...). Similarly, in shot 2, a second spherical k-space is constructed using multiple navi echo signals N, and a second imaging k-space portion is constructed using multiple imaging echo signals E. Based on navi echo signals N, correction function 103 calculates the movement of the second spherical k-space relative to the first spherical k-space. This movement includes rotation and translation between the two spherical k-spaces. Conventional techniques can be used to calculate the rotation angle and translation amount between the two spherical k-spaces, and details will not be described here.

[0039] The correction function 103 corrects the second imaging k-space portion based on the amount of movement of the second spherical k-space relative to the first spherical k-space, i.e., the rotation angle and the amount of translation, to generate a corrected second imaging k-space portion. Thereafter, the image generation function 104 performs image reconstruction of the detection region of the subject using an imaging k-space consisting of the corrected second imaging k-space portion and the reference first imaging k-space portion.

[0040] In the two shots, the amount of movement between the spherical k-spaces is the amount of movement of the examination area of ​​the subject, and this amount of movement is used to correct the imaging k-space portion constructed in the imaging stage adjacent to the stabilization stage. Since this amount of movement can be recognized as the amount of movement of the examination area of ​​the subject in the imaging stage, accurate correction can be made to the imaging k-space portion.

[0041] Even if the examination region of the subject moves, the amount of movement of the second imaging k-space portion is corrected, so that the occurrence of motion artifacts in the reconstructed image is suppressed.

[0042] The above describes a case where imaging includes two shots, shot 1 and shot 2, and where the imaging k-space portion is corrected using these two adjacent shots, but this is not limited to this. For example, imaging may include three or more shots, and non-adjacent shots may be used to correct the imaging k-space portion. For example, correction may be possible between shot 1 and shot 3, between shot 1 and shot 4, or between shot 2 and shot 5. In other words, the imaging k-space portion constructed by the subsequent shot is corrected based on the amount of movement of the spherical k-space constructed by the subsequent shot relative to the spherical k-space. In this way, the imaging k-space portion constructed by the subsequent shot is corrected so that it does not move compared to the imaging k-space portion constructed by the previous shot.

[0043] Furthermore, since the examination region of the subject is a rigid body, the movement amount (translation amount and rotation angle) of a certain part in the examination region of the subject can be regarded as the movement amount of the entire examination region. That is, the movement amount calculated by the processing circuit 100 includes the rotation angle and translation amount between spherical k-spaces. Note that the shot used as the reference for correcting the movement amount does not necessarily have to be the shot acquired earlier in the chronological order, and it is also possible to use a shot acquired later in the chronological order as the reference.

[0044] A method for three-dimensionally imaging an examination region of a subject will be described below with reference to FIG. 4. In step S11, the acquisition function 102 performs data acquisition of multiple shots in accordance with sequence execution data, such as acquiring a navi echo signal N in a stabilization stage S1 and acquiring an imaging echo signal E in an imaging stage S2. The multiple shots include at least shot 1 and shot 2. In shot 1, a first navi echo signal and a first imaging echo signal are acquired. In shot 2, a second navi echo signal and a second imaging echo signal are acquired. Here, the data acquired in shot 1 is used as the reference, and the data acquired in shot 2 is the target of correction.

[0045] In step S12, the correction function 103 calculates a correction value due to subject movement between shots based on the first navi-echo signal and the second navi-echo signal. In step S13, the correction function 103 corrects the second imaging k-space data obtained in shot 2 using the correction value calculated in step S12. Note that the correction process may include a gridding process. That is, the processing circuitry 100 may use the correction function 103 to perform a gridding process on the corrected imaging k-space.

[0046] In step S14, the image generation function 104 constructs complete k-space data using the first imaging k-space data and the corrected second imaging k-space data, and performs processing such as Fourier transform on the complete k-space data to generate an MR image. That is, the processing circuitry 100 generates an image of the examination region using the corrected imaging k-space using the image generation function 104.

[0047] According to at least one of the embodiments described above, it is possible to improve the accuracy of motion correction.

[0048] As a comparative example of the present invention, we will explain the PROMO (Prospective Motion Correction) sequence, a motion correction technique. As shown in FIG. 5, PROMO acquires data along three mutually perpendicular planes—the coronal plane, the sagittal plane, and the axial plane—before the imaging sequence ET. The data acquisition section before the imaging sequence ET is called the navigator segment NS. Subject movement is estimated based on the data acquired during the navigator segment NS, and the imaging sequence ET is corrected based on the estimated results to suppress motion artifacts. When FLAIR imaging and PROMO are used together, the application of an IR pulse is inserted between the navigator segment NS and the imaging phase, so the correction value acquired during the navigator segment NS may not be appropriate for the correction during the imaging phase. In other words, because a time lag occurs between the navigator segment NS and the imaging phase, subject movement occurring between the navigator segment NS and the imaging phase cannot be accurately corrected. Furthermore, this motion correction requires the support of a scanner with a hardware feedback loop, which is also hardware-intensive.

[0049] On the other hand, according to at least one of the embodiments described above, since the stabilization phase is utilized to acquire motion-corrected data, even when IR pulses are used in combination, the timing of acquiring the motion-corrected data is prevented from being shifted in time relative to the acquisition of the imaging phase, thereby improving the accuracy of the correction data. The improved accuracy of the correction data allows for better suppression of motion artifacts in MR images.

[0050] Furthermore, in accordance with at least one embodiment described above, the correction is performed automatically and does not require a scanner with a hardware feedback loop, eliminating the need for additional hardware.

[0051] According to at least one of the embodiments described above, when constructing the spherical k-space, the points in each navi-echo signal are arranged alternately, so that even if the subject moves between two shots, the amount of movement can be corrected, thereby obtaining accurate k-space data. However, the spherical k-space can also be constructed using other construction methods. For example, the spherical k-space can be constructed by arranging multiple points in the first navi-echo signal, multiple points in the second navi-echo signal, etc., in order on a sphere.

[0052] According to at least one of the embodiments described above, image quality can be improved.

[0053] Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations of embodiments can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0054] 100 Processing Circuit 101 Bed control function 102 Collection Function 103 Correction function 104 Image generation function 105 Display control function

Claims

1. 1. A magnetic resonance imaging apparatus for imaging an examination region of a subject, comprising: an acquisition unit that continuously acquires navi-echo signals and imaging signals from the examination region in each of a plurality of shots; a correction unit that calculates a movement amount of the subject using a plurality of navi-echo k-space data that are respectively generated based on the navi-echo signals in the plurality of shots, and corrects the imaging k-space data that are generated based on the imaging signals in the plurality of shots; an image generating unit that generates an image of the examination region using the corrected imaging k-space data, the acquisition unit acquires a plurality of Navi-Echo signals for each shot; A magnetic resonance imaging apparatus, wherein the plurality of navi-echo signals each consist of a plurality of data points including a first data point and a second data point, the first data point and the second data point of each of the plurality of navi-echo signals are different data points for each of the plurality of navi-echo signals, the plurality of data points are arranged spirally on a spherical surface in three-dimensional k-space, and acquisition of the plurality of navi-echo signals at each of the second data points is performed after acquisition of each of the plurality of navi-echo signals at the first data point is completed.

2. the plurality of shots includes a first shot and a second shot; 2. The magnetic resonance imaging apparatus according to claim 1, wherein the correction unit corrects the imaging k-space data constructed by the second shot based on the amount of movement of the imaging k-space data constructed by the second shot relative to the navi-echo k-space data constructed by the first shot.

3. The magnetic resonance imaging apparatus according to claim 1 , wherein the correction unit further performs gridding processing on the corrected imaging k-space data.

4. The magnetic resonance imaging apparatus according to claim 1 , wherein the acquisition unit acquires the navi-echo signals in a stabilization stage for stabilizing the subsequent imaging signals.

5. the test site is a rigid body, The magnetic resonance imaging apparatus according to claim 1 , wherein the amount of movement includes a rotation angle and a translation amount between spherical surfaces in three-dimensional k-space.

6. 1. A magnetic resonance imaging method for imaging an examination region of a subject, comprising: sequentially acquiring navi-echo signals and imaging signals from the examination region during each of a plurality of shots; Calculating a movement amount of the subject using a plurality of k-space data respectively generated based on the navi-echo signals in the plurality of shots, and correcting the imaging k-space data generated based on the imaging signals in the plurality of shots; generating an image of the examination region using the corrected imaging k-space data; The acquisition involves acquiring a plurality of Navi-Echo signals for each shot; A magnetic resonance imaging method, wherein the plurality of navi-echo signals each consist of a plurality of data points including a first data point and a second data point, the first data point and the second data point of each of the plurality of navi-echo signals are different data points for each of the plurality of navi-echo signals, the plurality of data points are arranged spirally on a spherical surface in three-dimensional k-space, and acquisition of the plurality of navi-echo signals at each of the second data points is performed after acquisition of each of the plurality of navi-echo signals at the first data point is completed.

7. the plurality of shots includes a first shot and a second shot; 7. The magnetic resonance imaging method according to claim 6, wherein the correction corrects the imaging k-space data constructed by the second shot based on a movement amount of the k-space data constructed by the second shot relative to the k-space data constructed by the first shot.

8. 7. The magnetic resonance imaging method according to claim 6, wherein the correction further comprises performing a gridding process on the corrected imaging k-space data.

9. 7. The magnetic resonance imaging method according to claim 6, wherein the acquisition comprises acquiring the navi-echo signals in a stabilization stage that stabilizes the subsequent imaging signals.

10. the test site is a rigid body, The magnetic resonance imaging method according to claim 6 , wherein the amount of movement includes a rotation angle and a translation amount between spherical surfaces in three-dimensional k-space.

Images