Magnetic resonance imaging apparatus, body movement-related shot identification method, and body movement-related shot identification program

Abstract

To detect the body motion of a subject about body motion correction without performing complicated calculation.SOLUTION: A magnetic resonance imaging apparatus according to an embodiment includes an acquisition unit, a comparison unit and an identification unit. The acquisition unit acquires a plurality of echo signals not to be encoded corresponding to a plurality of respective shots about acquisition of a plurality of echo signals having been encoded by magnetic resonance imaging for a subject. The comparison unit compares the echo signals not to be encoded with each other about the shots. The identification unit identifies a shot to be removed about generation of a magnetic resonance image about the subject out of the shots based on a comparison result of the echo signals not to be encoded.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The embodiments disclosed in the present specification and drawings relate to a magnetic resonance imaging apparatus, a method for identifying body motion-related shots, and a program for identifying body motion-related shots. [Background technology]

[0002] Conventionally, magnetic resonance image generation is vulnerable to the movement of the subject being imaged. Therefore, even a slight movement of the subject during imaging can cause artifacts in the generated magnetic resonance image. For this reason, in order to reduce artifacts caused by subject movement in magnetic resonance images, methods have been proposed for identifying data with movement (hereinafter referred to as motion data) in k-space data related to the generation of magnetic resonance images. Such methods include, for example, a method of identifying motion data in k-space by tracking the movement of the subject using a navigator, a method of calculating the amount of movement of all data in k-space from a physical model, and a method of performing motion correction on all data in k-space without identifying motion data.

[0003] However, using a navigator requires additional sequences that can increase imaging time, and calculating motion from a physical model and performing motion correction on all data can be computationally expensive and time-consuming. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-29777 Summary of the Invention [Problem to be solved by the invention]

[0005] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to detect the body movement of a subject related to body movement correction without performing complex calculations. 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]

[0006] The MRI apparatus according to the embodiment is equipped with a processing circuit that acquires, by magnetic resonance imaging of a subject, a plurality of non-encoded echo signals corresponding to a plurality of shots for acquiring a plurality of encoded echo signals, compares the non-encoded echo signals for the plurality of shots, and identifies, from the plurality of shots, a shot that should be removed for generating a magnetic resonance image of the subject based on a comparison result of the non-encoded echo signals. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing an example of an MRI apparatus according to an embodiment. [Figure 2] FIG. 2 is a flowchart showing an example of a procedure for a body movement correction process according to the embodiment. [Figure 3] FIG. 3 is a diagram showing an example of a comparison CP in which a dummy echo signal related to a first shot is used as a reference echo signal and a plurality of dummy echo signals in other shots (second to fourth shots) according to the embodiment. [Figure 4] FIG. 4 is a flowchart illustrating an example of a procedure of a removal determination process according to a first application example of the embodiment. [Figure 5] FIG. 5 is a flowchart illustrating an example of a procedure of a removal determination process according to a second application example of the embodiment. [Figure 6] FIG. 6 is a diagram showing an example of validity and invalidity of specifying shots to be removed using a first threshold value and a second threshold value for a first difference and a second difference according to a third application example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, with reference to the drawings, a magnetic resonance imaging (hereinafter referred to as MRI) device, a method for identifying body motion-related shots, and a computer-readable non-volatile storage medium storing a program for identifying body motion-related shots will be described. In the following embodiments, parts with the same reference numerals perform similar operations, and redundant explanations will be omitted as appropriate. Furthermore, for the sake of concreteness, the method for identifying body motion-related shots and the program for identifying body motion-related shots will be described as being implemented by an MRI device.

[0009] The technical features of the body-motion-related shot identification method and / or the body-motion-related shot identification program may be realized by a server device (such as a medical information processing device or a medical image processing device) that can realize the body-motion-related shot identification method and / or the body-motion-related shot identification program. In this case, the server device is considered to be included in the MRI device.

[0010] Furthermore, the technical idea of ​​this embodiment may be applied to various modalities combined with an MRI device, such as a PET (Positron Emission Tomography)-MRI device or a SPECT (single photon emission computed tomography)-MRI device.

[0011] The present embodiment aims to detect a subject's body motion related to body motion correction without performing complex calculations. For example, one of the problems to be solved by the embodiments disclosed in this specification and the drawings is to detect a subject's body motion related to body motion correction without performing complex calculations. 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 respective effects of each configuration described in the embodiments below can also be positioned as other problems. The MRI apparatus described in the following embodiments includes a processing circuit that performs magnetic resonance imaging of a subject to acquire multiple non-encoded echo signals corresponding to multiple shots for acquiring multiple encoded echo signals, compares the non-encoded echo signals with respect to the multiple shots, and identifies shots to be removed from the multiple shots for generating a magnetic resonance image of the subject based on the comparison results of the non-encoded echo signals.

[0012] (Embodiment) Fig. 1 is a diagram showing an example of an MRI apparatus 100 according to this embodiment. As shown in Fig. 1, the MRI apparatus 100 includes a static magnetic field magnet 101, a gradient magnetic field coil 103, a gradient magnetic field power supply 105, a bed 107, a bed control circuit 109, a transmission circuit 113, a transmission coil 115, a reception coil 117, a reception circuit 119, an imaging control circuit (imaging control unit) 121, a system control circuit (system control unit) 123, a memory 125, an input interface 127, a display 129, and a processing circuit 131.

[0013] The static magnetic field magnet 101 is a magnet formed in a hollow, approximately cylindrical shape. The static magnetic field magnet 101 generates a substantially uniform static magnetic field in the internal space. For example, a superconducting magnet or the like is used as the static magnetic field magnet 101.

[0014] The gradient magnetic field coil 103 is a hollow, approximately cylindrical coil and is disposed on the inner surface of the cylindrical cooling vessel. The gradient magnetic field coil 103 receives current individually from a gradient magnetic field power supply 105 to generate gradient magnetic fields whose magnetic field strength changes along the mutually orthogonal X, Y, and Z axes. The gradient magnetic fields of the X, Y, and Z axes generated by the gradient magnetic field coil 103 form, for example, a slice selection gradient magnetic field, a phase encoding gradient magnetic field, and a frequency encoding gradient magnetic field. The slice selection gradient magnetic field is used to arbitrarily determine an imaging cross section. The phase encoding gradient magnetic field is used to change the phase of a magnetic resonance signal (hereinafter referred to as an MR (Magnetic Resonance) signal) according to a spatial position. The frequency encoding gradient magnetic field is used to change the frequency of the MR signal according to a spatial position.

[0015] The gradient magnetic field power supply 105 is a power supply device that supplies current to the gradient magnetic field coil 103 under the control of the imaging control circuit 121 .

[0016] The bed 107 is a device equipped with a top plate 1071 on which the subject P is placed. The bed 107 inserts the top plate 1071 on which the subject P is placed into the bore 111 under the control of a bed control circuit 109.

[0017] The bed control circuit 109 is a circuit that controls the bed 107. The bed control circuit 109 drives the bed 107 in response to instructions from the operator via the input interface 127, thereby moving the tabletop 1071 in the longitudinal direction, the up-down direction, and in some cases the left-right direction.

[0018] The transmission circuit 113 supplies radio frequency pulses modulated at the Larmor frequency to the transmission coil 115 under the control of the imaging control circuit 121. For example, the transmission circuit 113 has an oscillator, a phase selection unit, a frequency conversion unit, an amplitude modulation unit, an RF (Radio Frequency) amplifier, and the like. The oscillator generates an RF pulse at a resonance frequency specific to the target atomic nucleus in a static magnetic field. The phase selection unit selects the phase of the RF pulse generated by the oscillator. The frequency conversion unit converts the frequency of the RF pulse output from the phase selection unit. The amplitude modulation unit modulates the amplitude of the RF pulse output from the frequency conversion unit according to, for example, a sinc function. The RF amplifier amplifies the RF pulse output from the amplitude modulation unit and supplies it to the transmission coil 115.

[0019] Furthermore, under the control of the imaging control circuit 121, the transmission circuit 113 supplies radio frequency pulses (hereinafter referred to as dummy radio frequency pulses) for acquiring echo signals that are not to be encoded (hereinafter referred to as dummy echo signals) to the transmission coil 115. The dummy radio frequency pulses are used, for example, to improve the stability of collection of a plurality of encoded echo signals. The transmission circuit 113 always supplies the dummy radio frequency pulses with the same intensity to the transmission coil 115. Note that the dummy radio frequency pulses are not limited to being generated by the transmission circuit, and may be supplied to the gradient magnetic field coil 103 from the gradient magnetic field power supply 105 under the control of the imaging control circuit 121 for the gradient magnetic field power supply 105, for example.

[0020] The transmit coil 115 is an RF coil disposed inside the gradient magnetic field coil 103. The transmit coil 115 generates an RF pulse corresponding to a radio frequency magnetic field in response to the output from the transmit circuit 113. The RF pulse is generated, for example, when acquiring an encoded echo signal. Hereinafter, an RF pulse related to acquiring an encoded echo signal (hereinafter referred to as an encode echo signal) is referred to as a shot. In other words, multiple shots correspond to multiple RF pulses related to acquiring multiple encoded echo signals. The encode echo signal for one shot is filled in accordance with the frequency encode gradient magnetic field along a line (hereinafter referred to as a phase encode line) corresponding to one phase encode value (k value) according to the magnitude of the phase encode gradient magnetic field. Note that the encode echo signal for one shot is not limited to filling in one phase encode line. For example, in the case of a fast spin echo method, the encode echo signal for one shot may be filled in accordance with the frequency encode gradient magnetic field along multiple phase encode lines. For the sake of concreteness, the following description assumes that there are multiple shots in MR imaging of a subject P.

[0021] Furthermore, the transmission coil 115 generates a high frequency magnetic field corresponding to the dummy high frequency pulse as a dummy pulse in accordance with the output from the transmission circuit 113. When the dummy high frequency pulse is realized by the gradient magnetic field power supply 105, the dummy pulse is generated by the gradient magnetic field coil 103 in accordance with the dummy high frequency pulse supplied from the gradient magnetic field power supply 105 to the gradient magnetic field coil 103. The generation of the dummy pulse is performed at a predetermined timing before or after the application of the RF pulse to the subject P.

[0022] The receiving coil 117 is an RF coil arranged inside the gradient magnetic field coil 103. The receiving coil 117 receives MR signals emitted from the subject P by a high frequency magnetic field. The receiving coil 117 outputs the received MR signals to a receiving circuit 119. The receiving coil 117 is, for example, a coil array having one or more, typically a plurality of coil elements (hereinafter referred to as a plurality of coils). For the sake of concreteness, the receiving coil 117 will be described below as a coil array having three coils as the plurality of coils.

[0023] The receiving coil 117 receives a dummy echo emitted from the subject P by the dummy pulse. The receiving coil 117 outputs the received dummy echo to the receiving circuit 119. When the subject P is stationary during MR imaging of the subject P, the signal value of the dummy echo signal is approximately constant depending on the multiple coils.

[0024] 1, the transmit coil 115 and the receive coil 117 are depicted as separate RF coils, but the transmit coil 115 and the receive coil 117 may be implemented as an integrated transmit / receive coil. The transmit / receive coil corresponds to the imaging region of the subject P and is, for example, a local transmit / receive RF coil such as a head coil.

[0025] The receiving circuit 119 generates a digital encoded echo signal based on the MR signal output from the receiving coil 117 under the control of the imaging control circuit 121. The digital encoded echo signal is also referred to as MR data. Specifically, the receiving circuit 119 performs signal processing such as detection and filtering on the MR signal output from the receiving coil 117, and then performs analog-to-digital (A / D) conversion (hereinafter referred to as A / D conversion) on the data that has undergone the signal processing to generate an encoded echo signal. The receiving circuit 119 outputs the generated encoded echo signal to the imaging control circuit 121. For example, the encoded echo signal is generated in each of a plurality of coils and output to the imaging control circuit 121 together with a tag that identifies each of the plurality of coils.

[0026] The receiving circuit 119 generates a digital dummy echo (hereinafter referred to as a dummy echo signal) based on the dummy echo output from the receiving coil 117 under the control of the imaging control circuit 121. Specifically, the receiving circuit 119 performs signal processing such as detection and filtering on the dummy echo output from the receiving coil 117, and then performs analog-to-digital (A / D) conversion (hereinafter referred to as A / D conversion) on the data that has undergone this signal processing to generate a dummy echo signal. The receiving circuit 119 outputs the generated dummy echo signal to the imaging control circuit 121. For example, the dummy echo signal is generated in each of a plurality of coils and output to the imaging control circuit 121 together with a tag that identifies each of the plurality of coils.

[0027] The imaging control circuit 121 controls the gradient magnetic field power supply 105, the transmission circuitry 113, the reception circuitry 119, etc. in accordance with the imaging protocol output from the processing circuitry 15, and performs imaging of the subject P. The imaging protocol has a pulse sequence according to the type of examination. The imaging protocol defines the magnitude of the current supplied to the gradient magnetic field coil 103 by the gradient magnetic field power supply 105, the timing at which the gradient magnetic field power supply 105 supplies the current to the gradient magnetic field coil 103, the magnitude and time width of the radio frequency pulse supplied to the transmission coil 115 by the transmission circuitry 113, the timing at which the radio frequency pulse is supplied to the transmission coil 115 by the transmission circuitry 113, the timing at which the MR signal is received by the reception coil 117, etc. The imaging protocol also defines the magnitude and time width of the dummy radio frequency pulse supplied to the transmission coil 115 by the transmission circuitry 113, the timing at which the dummy radio frequency pulse is supplied to the transmission coil 115 by the transmission circuitry 113, the timing at which the dummy echo is received by the reception coil 117, etc. The imaging control circuit 121 supplies a dummy high-frequency pulse to the transmission circuit 113 and acquires a dummy echo signal from the reception circuit 119 for each of a plurality of shots.

[0028] When the imaging control circuit 121 receives an encoded echo signal from the receiving circuit 119 as a result of driving the gradient magnetic field power supply 105, the transmitting circuit 113, the receiving circuit 119, etc. to image the subject P, the imaging control circuit 121 transfers the received encoded echo signal to the processing circuit 131. Furthermore, when the imaging control circuit 121 receives a dummy echo signal from the receiving circuit 119 during the execution of MR imaging of the subject P, the imaging control circuit 121 transfers the received dummy echo signal to the processing circuit 131.

[0029] The imaging control circuit 121 is realized by, for example, a processor. The term "processor" refers to a circuit such as a CPU, a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA)).

[0030] The system control circuit 123 has hardware resources such as a processor, a read-only memory (ROM), a random access memory (RAM), etc. (not shown), and uses a system control function to control the MRI apparatus 100. Specifically, the system control circuit 123 reads a system control program stored in the memory, expands it on the memory, and controls each circuit of the MRI apparatus 100 according to the expanded system control program.

[0031] For example, the system control circuit 123 reads out an imaging protocol from the memory 125 based on imaging conditions input by the operator via the input interface 127. The system control circuit 123 transmits the imaging protocol to the imaging control circuit 121 and controls imaging of the subject P. The system control circuit 123 is realized by, for example, a processor. The system control circuit 123 may be incorporated into the processing circuit 15. In this case, the system control function is executed by the processing circuit 15, and the processing circuit 15 functions as a substitute for the system control circuit 123. The processor that realizes the system control circuit 123 is similar to that described above, and therefore a description thereof will be omitted.

[0032] The memory 125 stores various programs related to the system control functions executed in the system control circuit 123, various imaging protocols, imaging conditions including a plurality of imaging parameters that define the imaging protocols, etc. The memory 125 also stores the acquisition function 33, the comparison function 35, the identification function 37, and the generation function 39 realized by the processing circuitry 15 in the form of programs executable by a computer.

[0033] The memory 125 also stores dummy echo signals acquired by the acquisition function 33, various data used in the processes performed by the identification function 37 and the generation function 39, MR images generated by the generation function 39, various data generated in the process of generating the MR images, etc. The various data stored in the memory 125 will be described later. The memory 125 also stores encoded echo signals acquired by scanning the subject P and an algorithm for reconstructing an MR image based on the encoded echo signals.

[0034] The memory 125 is realized by, for example, a semiconductor memory element such as a ROM, a RAM, or a flash memory, a hard disk drive (HDD), a solid state drive (SSD), an optical disk, etc. The memory 125 may also be realized by a drive device that reads and writes various information from and to a portable storage medium such as a CD (Compact Disc)-ROM drive, a DVD (Digital Versatile Disc) drive, or a flash memory.

[0035] The input interface 127 accepts various instructions (e.g., a power-on instruction) and information input from an operator. The input interface 127 may be realized by, for example, 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. The input interface 127 is connected to the processing circuitry 131, converts input operations received from the operator into electrical signals, and outputs the converted electrical signals to the processing circuitry 131. Note that, in this specification, the input interface 127 is not limited to those having physical operation components such as a mouse and a keyboard. For example, an electrical signal processing circuit that receives electrical signals corresponding to input operations from an external input device provided separately from the MRI apparatus 100 and outputs the electrical signals to a control circuit is also included as an example of the input interface 127.

[0036] The display 129 displays various GUIs (Graphical User Interfaces) and MR images generated by the generation function 39 in the processing circuitry 131 under the control of the processing circuitry 131 or the system control circuitry 123. The display 129 also displays imaging parameters related to scans and various information related to image processing. The display 129 is realized by, for example, a CRT display, a liquid crystal display, an organic EL display, an LED display, a plasma display, or any other display or monitor known in the art.

[0037] The processing circuit 131 is realized by, for example, the above-mentioned processor. The processing circuit 131 includes an acquisition function 33, a comparison function 35, a determination function 37, a generation function 39, and the like. The processing circuits 131 that realize the acquisition function 33, the comparison function 35, the determination function 37, and the generation function 39, respectively, correspond to an acquisition unit, a comparison unit, a determination unit, and a generation unit. Each function, such as the acquisition function 33, the comparison function 35, the determination function 37, and the generation function 39, is stored in the memory 125 in the form of a program executable by a computer. For example, the processing circuit 131 realizes the function corresponding to each program by reading and executing the program from the memory 125. In other words, the processing circuit 131 in a state in which each program has been read has each function, such as the acquisition function 33, the comparison function 35, the determination function 37, and the generation function 39.

[0038] In the above description, an example has been described in which the "processor" reads and executes a program corresponding to each function from memory 125, but the embodiment is not limited to this. If the processor is, for example, a CPU, the processor realizes the function by reading and executing a program stored in memory 125. On the other hand, if the processor is an ASIC, instead of storing a program in memory 125, the function is directly incorporated into the processor circuit as a logic circuit. Note that each processor in this embodiment is not limited to being configured as a single circuit per processor, and multiple independent circuits may be combined to configure a single processor and realize its function. Furthermore, while the description has been given assuming that a single storage circuit stores a program corresponding to each processing function, multiple storage circuits may be distributed and the processing circuit 131 may read the corresponding program from each individual storage circuit.

[0039] The processing circuitry 131 acquires, by MR imaging of the subject P, a plurality of non-encoded echo signals corresponding to a plurality of shots related to acquisition of a plurality of encoded echo signals, using the acquisition function 33. That is, the acquisition function 33 acquires a dummy echo signal for each of the plurality of shots. The acquisition function 33 stores the acquired dummy echo signals in the memory 125. Note that when the processing circuitry 131 is installed in a server such as a medical information processing device or a medical image processing device, the acquisition function 33 acquires the dummy echo signals from a normal MRI device.

[0040] The processing circuit 131 uses the comparison function 35 to compare a plurality of echo signals not to be encoded for a plurality of shots. That is, the comparison function 35 compares a plurality of dummy echo signals corresponding to the plurality of shots. Specifically, the comparison function 35 uses a non-encoding echo signal related to a reference shot (hereinafter referred to as a reference shot) among the plurality of echo signals not to be encoded as a reference echo signal, and compares the reference echo signal with the plurality of echo signals not to be encoded. The reference shot is, for example, the first shot (hereinafter referred to as the first shot) among the plurality of shots. Hereinafter, the dummy echo signal related to the reference shot will be referred to as the reference echo signal.

[0041] More specifically, for each of the multiple shots, the comparison function 35 calculates a correlation value between the dummy echo signal in the first shot and the dummy echo signal in the other shots for each of the multiple coils. Note that the comparison function 35 may calculate a difference value instead of a correlation value. For example, if there are four multiple shots, the comparison function 35 calculates, for each of the multiple coils, a correlation value between the reference echo signal and the dummy echo signal in the second shot, a correlation value between the reference signal and the dummy echo signal in the third shot, and a correlation value between the reference signal and the dummy echo signal in the fourth shot. That is, if the total number of multiple shots is N (N is a natural number equal to or greater than 2) and the total number of multiple coils is M (M is a natural number equal to or greater than 1), the comparison function 35 calculates (N-1) × M correlation values ​​as comparison results.

[0042] The processing circuitry 131 uses the identification function 37 to identify, from among the multiple shots, shots that should be removed for generating an MR image of the subject P based on the comparison results of multiple echo signals that are not to be encoded. For example, the identification function 37 identifies, from among the multiple echo signals that are not to be encoded, a shot related to an echo signal that is not to be encoded and has the smallest correlation with a reference echo signal as the shot to be removed. Furthermore, when the correlation values ​​for multiple shots are similar, the identification function 37 identifies the reference shot as the shot to be removed.

[0043] Specifically, the identifying function 37 identifies the shot containing the dummy echo signal with the smallest correlation value among the multiple correlation values ​​calculated by the comparing function 35. Furthermore, if the multiple correlation values ​​are substantially the same, that is, if the multiple correlation values ​​fall within a predetermined range, the identifying function 37 identifies the first shot as the shot to be removed. The predetermined range is, for example, a range from 0.9999 to 0.9995, and is preset and stored in the memory 125.

[0044] The processing circuitry 131 generates an MR image of the subject P using the generation function 39 without using encoded echo signals corresponding to a specified shot (hereinafter referred to as a specific shot). Specifically, the generation function 39 generates an MR image with motion correction of the subject P without using encoded echo signals corresponding to the specific shot. For example, the generation function 39 arranges multiple encoded echo signals related to multiple shots other than the specific shot in k-space based on the frequency encoding gradient magnetic field and the phase encoding gradient magnetic field without using encoded echo signals related to the specific shot. The generation function 39 generates an MR image by performing reconstruction processing with motion correction on the multiple encoded echo signals arranged in k-space. Since known techniques can be used as appropriate for motion correction, a description thereof will be omitted.

[0045] The motion correction process executed by the MRI apparatus 100 of this embodiment configured as described above will be described with reference to Figures 2 and 3. The motion correction process is a process of identifying shots related to the subject's motion based on dummy echo signals and generating an MR image without using encoded echo signals related to the identified shots. For the sake of concreteness, it is assumed below that the number of coils in the receive coil 117 is three and the number of shots is four.

[0046] Fig. 2 is a flowchart showing an example of the procedure for the body motion correction process. Fig. 3 is a diagram showing an example of a reference echo signal to be compared and a dummy echo signal for each shot and coil in the body motion correction process.

[0047] (Body motion correction processing) (Step S201) The imaging control circuit 121 executes a dummy pulse for each shot and performs MR imaging of the subject P. The processing circuit 131 acquires a dummy echo signal for each shot using the acquisition function 33. The acquisition function 33 stores the acquired dummy echo signal in the memory 125. Note that when the body motion correction process is implemented by a server device such as a medical information processing device or a medical image processing device, the acquisition function 33 acquires the dummy echo signal from a normal MRI device.

[0048] (Step S202) The processing circuit 131 uses the comparison function 35 to compare the multiple dummy echo signals for each of the multiple coils, using the dummy echo signal corresponding to the first shot as a reference echo signal. For example, the comparison function 35 calculates a correlation value of the dummy echo signal with the reference echo signal for each shot and for each coil. The comparison function 35 stores the calculated correlation value in the memory 125 as a comparison result.

[0049] 3 is a diagram showing an example of a comparison CP in which a dummy echo signal related to the first shot is used as a reference signal and a plurality of dummy echo signals in other shots (second to fourth shots). As shown in FIG. 3, in the first and second shots, and in the first and third shots, the dummy echo signals and reference echo signals acquired from each of the first to third plurality of coils have approximately the same signal values. Therefore, the correlation value related to the first and second shots and the correlation value related to the first and third shots are both close to 1.

[0050] 3, the signal values ​​of the dummy echo signals acquired from the first to third coils in the first and fourth shots are lower than the signal value of the reference echo signal, so the correlation value between the first and fourth shots is lower than 1.

[0051] (Step S203) The processing circuitry 131 uses the identification function 37 to identify the shot associated with the dummy echo signal having the smallest correlation with the reference echo signal as the shot to be removed for generating an MR image. In FIG. 3, the fourth shot is identified as the shot to be removed. Note that in FIG. 3, if the correlation values ​​associated with the other shots relative to the first shot are all approximately the same, the identification function 37 identifies the first shot as the shot to be removed. The identification function 37 stores the identified shot (identified shot) in the memory 125. Since the difference between the reference echo signal and the dummy echo signal corresponds to the magnitude of the body movement of the subject P, the identified shot corresponds to the shot at the time when the body movement of the subject P is greatest.

[0052] (Step S204) The processing circuitry 131 generates an MR image with motion correction of the subject P using the generation function 39, without using encoded echo signals corresponding to the specific shot. That is, the generation function 39 performs motion correction on multiple encoded echo signals corresponding to multiple shots other than the specific shot, to generate an MR image. The generation function 39 stores the generated MR image in the memory 125. The generation function 39 may also display the generated MR image on the display 129.

[0053] The MRI apparatus 100 according to the embodiment described above acquires, by MR imaging of the subject P, a plurality of dummy echo signals corresponding to a plurality of shots related to the acquisition of a plurality of encoded echo signals, compares the plurality of dummy echo signals for the plurality of shots, and identifies a shot to be removed from the plurality of shots for generating an MR image of the subject P based on the comparison result of the plurality of dummy echo signals. For example, the MRI apparatus 100 according to the embodiment uses a dummy echo signal related to a reference shot among the plurality of dummy echo signals as a reference echo signal, and calculates a correlation value between the reference echo signal and the plurality of dummy echo signals as a comparison result. Furthermore, in the MRI apparatus 100 according to the embodiment, the reference shot is the first shot executed among the plurality of shots. For example, the MRI apparatus 100 according to the embodiment generates an MR image of the subject P with body motion correction without using an encoded echo signal corresponding to a specific shot.

[0054] Furthermore, the MRI apparatus 100 according to the embodiment specifies, as a shot to be removed, a shot related to a dummy echo signal having the smallest correlation with the reference echo signal among a plurality of dummy echo signals. On the other hand, when the correlation values ​​of a plurality of shots are similar, the MRI apparatus 100 according to the embodiment specifies the reference shot as a shot to be removed.

[0055] From these facts, the MRI apparatus 100 according to the embodiment can detect the movement (body movement) of the subject P by utilizing the fact that the dummy echo signals, which are not encoded, can theoretically be collected at all times with the same signal strength, and that the signal values ​​of the dummy echo signals change in accordance with a change in the relative positional relationship between the subject P and the MRI apparatus 100 and / or each of the multiple coils in accordance with the movement of the subject P. That is, the MRI apparatus 100 according to the embodiment can monitor the movement of the subject P for each shot, for example, by using the dummy echo signals used to improve the stability of collection of encoded echo signals.

[0056] As a result, the MRI apparatus 100 according to the embodiment can detect the subject's body motion related to body motion correction by calculating correlation values ​​with low calculation costs, without performing costly and complicated calculations, and without extending the imaging time. Therefore, the MRI apparatus 100 according to the embodiment can effectively reduce the influence of the subject's body motion (motion artifacts) by removing MR data related to shots corresponding to the detected body motion, i.e., data with motion, from the reconstruction, thereby generating an MR image with improved image quality. As described above, the MRI apparatus 100 according to the embodiment can improve the throughput of image diagnosis for the subject P without reducing the throughput of MR imaging for the subject P.

[0057] (First application example) In the embodiment, even if there is no body movement of the subject P, the encoded echo signals used to generate the MR image are removed due to the influence of noise, etc. Therefore, when there is no body movement of the subject P, the signal-to-noise ratio (hereinafter referred to as SNR) in the MR image generated in the embodiment decreases, and the influence of noise appears in the MR image, that is, the MR image may become noisy. For these reasons, in this application example, a valid / invalid determination (hereinafter referred to as removal determination) is performed regarding the identification of shots to be removed.

[0058] 4 is a flowchart showing an example of a procedure for processing related to removal determination (hereinafter referred to as removal determination processing). The processing of step S401 shown in FIG.

[0059] (Removal determination process) (Step S401) The processing circuitry 131 generates a first MR image with subject motion correction without using an encoded echo signal corresponding to a specific shot, using the generation function 39. The generation function 39 stores the first MR image in the memory 125. The method for generating the first MR image is similar to that in step S204, and therefore a description thereof will be omitted.

[0060] (Step S402) The processing circuitry 131 applies phase correction corresponding to motion correction to the encoded echo signals for the specific shot using the generation function 39. As a result, the generation function 39 performs phase correction corresponding to motion correction on the encoded echo signals for the specific shot. The generation function 39 generates k-space data corresponding to the first MR image by performing a Fourier transform on the first MR image. The generation function 39 restores the encoded echo signals to which the phase correction has been applied in the k-space data. That is, the generation function 39 replaces the data of the phase encoding line for the specific shot in the k-space data with the phase-corrected encoded echo signals. As a result, the generation function 39 generates restored k-space data in which the encoded echo signals for the specific shot have been restored in the k-space data corresponding to the first MR image.

[0061] (Step S403) The processing circuitry 131 generates a second MR image based on the restored k-space data using the generation function 39. Specifically, the generation function 39 generates the second MR image by performing a Fourier transform on the restored k-space data.

[0062] (Step S404) The processing circuitry 131 compares the first MR image and the second MR image using the comparison function 35. Specifically, the comparison function 35 calculates the difference between the first MR image and the second MR image. For example, the comparison function 35 calculates a value corresponding to the difference based on the difference between the first MR image and the second MR image. The value corresponding to the difference may be, for example, the sum of multiple pixel values ​​in the difference image between the first MR image and the second MR image, the average of the multiple pixel values, or the like. Note that the comparison function 35 may calculate a statistical value indicating the correlation between the first MR image and the second MR image as the difference. The statistical value may be a correlation value, a similarity, or the like.

[0063] (Step S405) The processing circuitry 131 uses the comparison function 35 to compare the calculated difference with a predetermined threshold. The predetermined threshold is a value used to determine whether or not there is a difference between the first MR image and the second MR image, and is set in advance and stored in the memory 125. For convenience of explanation, the predetermined threshold will be referred to as the first threshold hereinafter. If the calculated difference is less than the first threshold (YES in step S405), the process of step S406 is executed. If the calculated difference is equal to or greater than the first threshold (NO in step S405), the process of step S408 is executed.

[0064] (Step S406) The processing circuitry 131 disables the identification of the shot to be removed by the identification function 37. For example, as shown in Fig. 3, if the identified shot is the fourth shot, the identification function 37 disables the identification of the fourth shot.

[0065] (Step S407) The processing circuitry 131 generates an MR image using the generation function 39 based on a plurality of encoded echo signals acquired by MR imaging of the subject P. Specifically, the generation function 39 performs body motion correction on the plurality of encoded echo signals to generate an MR image.

[0066] (Step S408) The processing circuitry 131 determines the first MR image as the MR image related to the subject P by the specifying function 37.

[0067] The MRI apparatus 100 according to the first application example of the embodiment described above generates a first MR image with motion correction for the subject P without using encoded echo signals corresponding to a specific shot, applies phase correction corresponding to the motion correction to the encoded echo signals for the specific shot, restores the phase-corrected echo signals in the k-space data corresponding to the first MR image, generates a second MR image based on the restored k-space data, and disables the identification of the shot to be removed if the difference between the first MR image and the second MR image is smaller than a first threshold.

[0068] As a result, the MRI apparatus 100 according to the first application example can determine whether or not there is body movement of the subject P based on the difference between the first MR image and the second MR image. When it is determined that there is no body movement of the subject P (YES in step S405), the MRI apparatus 100 according to the first application example can generate an MR image of the subject P based on a plurality of encoded echo signals (all MR data) acquired by MR imaging of the subject P. From these facts, the MRI apparatus 100 according to the first application example can generate an MR image with a high SNR when it is determined that there is no body movement of the subject P (YES in step S405), thereby improving the throughput of image diagnosis for the subject P.

[0069] (Second application example) In the first application example, removal determination is performed on an image basis, but in this application example, removal determination is performed on k-space data. Fig. 5 is a flowchart showing an example of the procedure for removal determination processing in this application example. The processing of step S501 shown in Fig. 5 is performed following step S203 in Fig. 2.

[0070] (Removal determination process) (Step S501) The processing circuitry 131 generates k-space data with subject motion correction without using encoded echo signals corresponding to specific shots using the generation function 39. The generation function 39 stores the k-space data in the memory 125. The k-space data corresponds to the Fourier transform of the first MR image. Since known methods can be used as appropriate to generate the k-space data, a description thereof will be omitted.

[0071] (Step S502) The processing circuitry 131 uses the comparison function 35 to compare an echo signal interpolated for a specific shot in the k-space data (hereinafter referred to as a complementary echo signal) with an encoded echo signal corresponding to the specific shot (hereinafter referred to as a specific echo signal). Specifically, the comparison function 35 calculates the difference between the complementary echo signal and the specific echo signal. For example, the comparison function 35 calculates a value corresponding to the difference based on the difference between the complementary echo signal and the specific echo signal. The value corresponding to the difference may be, for example, a difference value between the interpolated echo signal and the specific echo signal. Note that the comparison function 35 may calculate a statistical value indicating the correlation between the complementary echo signal and the specific echo signal as the difference. The statistical value may be a correlation value, a similarity, or the like.

[0072] (Step S503) The processing circuit 131 uses the comparison function 35 to compare the calculated difference with a predetermined threshold. Because the predetermined threshold is different from the first threshold, it will be referred to as the second threshold hereinafter for convenience of explanation. The second threshold is a value used to determine whether or not there is a difference between the complementary echo signal and the specific echo signal, and is set in advance and stored in the memory 125. If the calculated difference is less than the second threshold (YES in step S503), the process of step S504 is executed. If the calculated difference is equal to or greater than the second threshold (NO in step S503), the process of step S506 is executed.

[0073] (Step S504) The processing circuitry 131 disables the identification of shots to be removed by the identification function 37. The processing in this step is similar to step S406 in FIG.

[0074] (Step S505) The processing circuitry 131 generates an MR image using the generation function 39 based on a plurality of encoded echo signals acquired by MR imaging of the subject P. The processing in this step is similar to step S407 in FIG. 4, and therefore description thereof will be omitted.

[0075] (Step S506) The processing circuitry 131 generates an MR image of the subject P based on the k-space data generated in step S501 using the generation function 39. Specifically, the generation function 39 generates the MR image by performing a Fourier transform on the k-space data.

[0076] The MRI apparatus 100 according to the second application example of the above-described embodiment generates k-space data with correction for the body motion of the subject P without using encoded echo signals corresponding to specific shots, and disables the identification of shots to be removed if the difference between the complementary echo signals in the k-space data and the specific echo signals is smaller than a second threshold. The effects of this application example are similar to those of the first application example, and therefore a description thereof will be omitted.

[0077] (Third application example) This application example combines the image-based removal determination in the first application example with the k-space data removal determination in the second application example. The removal determination in this application example conforms to the first and second application examples, and therefore will not be described further. Hereinafter, for ease of explanation, the difference compared with the first threshold will be referred to as the first difference, and the difference compared with the second threshold will be referred to as the second difference. Furthermore, the first difference and the second difference correspond to the difference, as described in the first and second application examples. In this application example, two determination criteria, the first threshold and the second threshold, are used, and therefore, an example of the relationship between these determination criteria, the image difference, and the signal difference will be described below.

[0078] FIG. 6 is a diagram showing an example of validity and invalidity of identifying shots to be removed using a first threshold and a second threshold for a first difference D1 and a second difference D2. The first upper limit value shown in FIG. 6 is a value greater than the first threshold and is set in advance. The second upper limit value shown in FIG. 6 is a value greater than the second threshold and is set in advance. The memory 125 stores the first upper limit value and the second upper limit value. Note that when a correlation value or a similarity is used as the first difference D1 and the second difference D2, the direction of the inequality sign shown in FIG. 6 is reversed, and the upper limit value corresponds to the lower limit value.

[0079] As shown in Fig. 6, when the first difference D1 is equal to or less than the first upper limit and the second difference D2 is equal to or less than the second upper limit, the identification of shots to be removed is disabled. Furthermore, when the first difference D1 exceeds the first upper limit and / or the second difference D2 exceeds the second upper limit, the identification of shots to be removed is enabled. The table shown in Fig. 6 is merely an example, and is not intended to be limiting. For example, the enablement or disablement of the identification of shots to be removed in the table shown in Fig. 6 may be appropriately set according to the SNR allowed for the image type of the MR image, or may be appropriately changed by a user's instruction via the input interface 127.

[0080] The MRI apparatus 100 according to the third application example of the above-described embodiment generates a first MR image with motion correction for the subject P without using encoded echo signals corresponding to specific shots, applies phase correction corresponding to the motion correction to the encoded echo signals corresponding to the specific shots to restore the phase-corrected echo signals in the k-space data corresponding to the first MR image, generates a second MR image based on the restored k-space data, calculates a first difference D1 between the first and second MR images, and a second difference D2 between the interpolated echo signals interpolated for the specific shots in the k-space data related to the first MR image and the encoded echo signals corresponding to the specific shots, and invalidates the identification of shots to be removed based on a first comparison result obtained by comparing the first difference D1 with a first threshold value and a second comparison result obtained by comparing the second difference D2 with a second threshold value. The removal determination and effects of this application example are similar to those of the first and second application examples, and therefore will not be described here.

[0081] (Fourth application example) In this application example, while MR imaging is being performed on a subject P, steps S201 to S203 in the body motion correction process shown in Figure 2 are performed in real time, MR imaging is performed again for shots to be removed, and encoded echo signals for the specific shots are obtained.

[0082] For example, the processing circuitry 131 acquires, using the acquisition function 33, each dummy echo signal in response to the execution of each of multiple shots during MR imaging of the subject P. The processing circuitry 131 compares, using the comparison function 35, multiple dummy echo signals for multiple shots in response to the acquisition of the dummy echo signals during MR imaging. The processing circuitry 131 identifies, using the identification function 37, a shot to be removed during MR imaging based on the comparison result. The processing circuitry 131 acquires, using the acquisition function 33, an encoded echo signal for a specific shot by additional MR imaging for the specific shot following the MR imaging. The processing circuitry 131 generates, using the generation function 39, an MR image of the subject P based on the multiple encoded echo signals corresponding to multiple shots excluding the specific shot and the reacquired encoded echo signals.

[0083] The processing circuitry 131 may specify the first and second shots as shots to be removed if the correlation between the dummy echo signal and the reference echo signal for the second shot is equal to or less than a predetermined value using the specifying function 37. In this case, the imaging control circuitry 121 performs MR imaging for the first and second shots again after the completion of the MR imaging currently being performed.

[0084] Furthermore, the identification of shots to be removed by the identification function 37 is not limited to being performed sequentially in response to the acquisition of dummy echo signals. For example, the processing circuitry 131 may cause the identification function 37 to identify shots to be removed in response to the acquisition of the third or fourth or subsequent dummy echo signals. Furthermore, the identification function 37 may perform identification of shots to be removed when the total number of dummy echo signals reaches a preset number.

[0085] The MRI apparatus 100 according to the fourth application example of the above-described embodiment acquires a plurality of dummy echo signals in response to the execution of a plurality of shots during MR imaging, compares the dummy echo signals for the plurality of shots in response to the acquisition of the dummy echo signals during the execution of the MR imaging, identifies a shot to be removed based on the comparison result between the dummy echo signals during the execution of the MR imaging, and re-acquires an encoded echo signal for the specific shot by MR imaging for the specific shot following the MR imaging.

[0086] As a result, the MRI apparatus 100 according to the fourth application example can detect the body movement of the subject P in real time by evaluating the dummy echo signals acquired simultaneously with the collection of encoded echo signals. Therefore, the MRI apparatus 100 according to the fourth application example can remove the encoded echo signals (MR data) and retake the image when the subject P moves during the collection of encoded echo signals. In other words, the MRI apparatus 100 according to the fourth application example can collect encoded echo signals with little body movement of the subject P.

[0087] For these reasons, the MRI apparatus 100 according to the fourth application example can effectively reduce motion artifacts without reducing the SNR, and generate MR images with improved image quality at low calculation costs. For these reasons, the MRI apparatus 100 according to this application example can improve the throughput of image diagnosis for the subject P without reducing the throughput of MR imaging for the subject P.

[0088] When the technical idea of ​​the embodiment is realized by a body-motion-related shot identification method, the body-motion-related shot identification method acquires, by MR imaging of the subject P, a plurality of echo signals not to be encoded corresponding to a plurality of shots related to the acquisition of a plurality of encoded echo signals, compares the plurality of echo signals not to be encoded for the plurality of shots, and, based on the comparison result of the plurality of echo signals not to be encoded, identifies, from the plurality of shots, shots to be removed for generating an MR image of the subject P. The procedure and effect of the body-motion correction process executed by the body-motion-related shot identification method are the same as those of the embodiment, and therefore description thereof will be omitted.

[0089] When the technical idea of ​​this embodiment is realized by a body-motion-related shot identification program, the body-motion-related shot identification program causes a computer to acquire, by MR imaging of a subject P, a plurality of echo signals not to be encoded corresponding to a plurality of shots related to acquisition of a plurality of encoded echo signals, compare the plurality of echo signals not to be encoded for the plurality of shots, and, based on the comparison result of the plurality of echo signals not to be encoded, identify shots to be removed from the plurality of shots for generating an MR image of the subject P. The body-motion-related shot identification program is stored, for example, in a computer-readable non-volatile storage medium.

[0090] For example, the body motion correction process can be realized by installing a body motion-related shot identification program from a non-volatile storage medium into various server devices (processing devices) related to medical data processing and expanding the program in memory. In this case, a program that can cause a computer to execute the method can also be stored and distributed on a storage medium such as a magnetic disk (such as a hard disk), an optical disk (such as a CD-ROM or DVD), or a semiconductor memory. The processing procedures and effects of the body motion-related shot identification program are the same as those in the embodiment, so a description thereof will be omitted.

[0091] According to at least one of the embodiments described above, it is possible to detect the body movement of the subject related to body movement correction without performing complex calculations.

[0092] 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]

[0093] 33 Acquisition Function 35 Comparison Function 37 Specific Functions 39 Generation function 100 Magnetic resonance imaging device (MRI device) 101 Static Magnetic Field Magnet 103 Gradient magnetic field coil 105 Gradient magnetic field power supply 107 Sleeper 109 Bed control circuit 111 Bore 113 Transmitting circuit 115 Transmitting Coil 117 Receiving Coil 119 Receiving circuit 121 Imaging control circuit (imaging control section) 123 System control circuit (system control section) 125 memory 127 input interface 129 Display 131 Processing circuit 1071 Top plate

Claims

1. an acquisition unit that acquires a plurality of non-encoded echo signals corresponding to a plurality of shots related to acquisition of a plurality of encoded echo signals by magnetic resonance imaging of a subject; a comparison unit that compares the plurality of non-encoding target echo signals for the plurality of shots; a specifying unit that specifies, from among the plurality of shots, a shot that should be removed in generating a magnetic resonance image of the subject, based on a comparison result of the plurality of echo signals that are not to be encoded; Equipped with the comparison unit uses an echo signal that is a non-target to be encoded and that is related to a reference shot among the plurality of shots as a reference echo signal, and calculates a correlation value between the reference echo signal and the plurality of non-target to be encoded echo signals as the comparison result; the reference shot is the first shot executed among the plurality of shots; Magnetic resonance imaging device.

2. An acquisition unit that acquires a plurality of non-encoded echo signals corresponding to a plurality of shots related to acquisition of a plurality of encoded echo signals by magnetic resonance imaging of a subject; a comparison unit that compares the plurality of non-encoding target echo signals for the plurality of shots; a specifying unit that specifies, from among the plurality of shots, a shot that should be removed in generating a magnetic resonance image of the subject, based on a comparison result of the plurality of echo signals that are not to be encoded; Equipped with the comparison unit uses an echo signal that is a non-target to be encoded and that is related to a reference shot among the plurality of shots as a reference echo signal, and calculates a correlation value between the reference echo signal and the plurality of non-target to be encoded echo signals as the comparison result; the specifying unit specifies the reference shot as the shot to be removed when the correlation values ​​for the plurality of shots are approximately the same; Magnetic resonance imaging device.

3. the specifying unit specifies, as the shot to be removed, a shot related to an echo signal that is not to be encoded and has the smallest correlation with the reference echo signal, among the plurality of echo signals that are not to be encoded.

3. A magnetic resonance imaging apparatus according to claim 1.

4. a generating unit that generates the magnetic resonance image without using encoded echo signals corresponding to the identified shot; 4. A magnetic resonance imaging apparatus according to claim 1.

5. An acquisition unit that acquires a plurality of non-encoded echo signals corresponding to a plurality of shots related to acquisition of a plurality of encoded echo signals by magnetic resonance imaging of a subject; a comparison unit that compares the plurality of non-encoding target echo signals for the plurality of shots; a specifying unit that specifies, from among the plurality of shots, a shot that should be removed in generating a magnetic resonance image of the subject, based on a comparison result of the plurality of echo signals that are not to be encoded; a generating unit that generates a first magnetic resonance image with motion correction of the subject without using encoded echo signals corresponding to the specified shot, applies phase correction corresponding to the motion correction to the encoded echo signals related to the specified shot, restores the echo signals to which the phase correction has been applied in k-space data corresponding to the first magnetic resonance image, and generates a second magnetic resonance image based on the restored k-space data; Equipped with the identifying unit invalidates the identification of the shot to be removed if a difference between the first magnetic resonance image and the second magnetic resonance image is smaller than a predetermined threshold. Magnetic resonance imaging device.

6. An acquisition unit that acquires a plurality of non-encoded echo signals corresponding to a plurality of shots related to acquisition of a plurality of encoded echo signals by magnetic resonance imaging of a subject; a comparison unit that compares the plurality of non-encoding target echo signals for the plurality of shots; a specifying unit that specifies, from among the plurality of shots, a shot that should be removed in generating a magnetic resonance image of the subject, based on a comparison result of the plurality of echo signals that are not to be encoded; a generating unit that generates k-space data with motion correction of the subject without using encoded echo signals corresponding to the specified shot; Equipped with the identifying unit invalidates the identification of the shot to be removed if a difference between an echo signal interpolated for the identified shot in the k-space data and the encoded echo signal corresponding to the identified shot is smaller than a predetermined threshold. Magnetic resonance imaging device.

7. An acquisition unit that acquires a plurality of non-encoded echo signals corresponding to a plurality of shots related to acquisition of a plurality of encoded echo signals by magnetic resonance imaging of a subject; a comparison unit that compares the plurality of non-encoding target echo signals for the plurality of shots; a specifying unit that specifies, from among the plurality of shots, a shot that should be removed in generating a magnetic resonance image of the subject, based on a comparison result of the plurality of echo signals that are not to be encoded; a generator that generates a first magnetic resonance image with motion correction of the subject without using encoded echo signals corresponding to the specified shot, applies phase correction corresponding to the motion correction to the encoded echo signals corresponding to the specified shot, restores the echo signals to which the phase correction has been applied in k-space data corresponding to the first magnetic resonance image, and generates a second magnetic resonance image based on the restored k-space data; Equipped with the comparison unit calculates a first difference between the first magnetic resonance image and the second magnetic resonance image, and a second difference between an echo signal interpolated for the specified shot in k-space data related to the first magnetic resonance image and the encoded echo signal corresponding to the specified shot; the identifying unit invalidates the identification of the shot to be removed based on a first comparison result obtained by comparing the first difference with a first threshold value and a second comparison result obtained by comparing the second difference with a second threshold value. Magnetic resonance imaging device.

8. the acquisition unit acquires each of the plurality of echo signals not to be encoded in response to execution of each of the plurality of shots during execution of the magnetic resonance imaging; the comparison unit compares the plurality of echo signals not to be encoded for the plurality of shots in response to acquisition of the echo signals not to be encoded during execution of the magnetic resonance imaging; the specifying unit specifies the shot to be removed based on the comparison result during the execution of the magnetic resonance imaging; the acquisition unit acquires again encoded echo signals related to the specified shot by magnetic resonance imaging related to the specified shot subsequent to the magnetic resonance imaging.

8. A magnetic resonance imaging apparatus according to claim 1.

9. a generating unit that generates the magnetic resonance image without using the encoded echo signals corresponding to the identified shot, and with motion correction for the subject; 8. A magnetic resonance imaging apparatus according to claim 1.

10. acquiring a plurality of non-encoded echo signals corresponding to a plurality of shots for acquiring a plurality of encoded echo signals by magnetic resonance imaging of the subject; comparing the non-encoded echo signals for the plurality of shots; Identifying a shot to be removed from the plurality of shots for generating a magnetic resonance image of the subject based on a comparison result of the plurality of non-encoding echo signals; an echo signal that is not an object to be encoded and that is related to a reference shot among the plurality of shots is used as a reference echo signal, and a correlation value between the reference echo signal and the plurality of echo signals that are not an object to be encoded is calculated as the comparison result; Equipped with the reference shot is the first shot executed among the plurality of shots; A method for identifying motion-related shots.

11. On the computer, acquiring a plurality of non-encoded echo signals corresponding to a plurality of shots for acquiring a plurality of encoded echo signals by magnetic resonance imaging of the subject; comparing the non-encoded echo signals for the plurality of shots; Identifying a shot to be removed from the plurality of shots for generating a magnetic resonance image of the subject based on a comparison result of the plurality of non-encoding echo signals; an echo signal that is not an object to be encoded and that is related to a reference shot among the plurality of shots is used as a reference echo signal, and a correlation value between the reference echo signal and the plurality of echo signals that are not an object to be encoded is calculated as the comparison result; Realize this, the reference shot is the first shot executed among the plurality of shots; Body movement related shot identification program.

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