Magnetic resonance imaging device, imaging method, and imaging program

Abstract

To reduce a time required for entire imaging, and to improve image quality.SOLUTION: A magnetic resonance imaging device includes a design unit and a collection unit. The design unit designs a pulse sequence for a slice position on a first slice group including a plurality of slices for multi-slice imaging by multi-cross section simultaneous excitation and a slice for a navigator echo. The collection unit performs simultaneous excitation for the first slice group and the slice for the navigator echo on the basis of the pulse sequence, and collects echo signals.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In MRI (Magnetic Resonance Imaging) imaging, if the subject moves, image blurring and ghost artifacts occur, and the quality of the data deteriorates. For example, when performing continuous imaging of the whole brain as in functional MRI (fMRI), if the head moves during the imaging, when trying to obtain minute signal changes in each region of the brain, signal changes due to positional shifts in the slice direction and in-plane direction cannot be ignored. Therefore, there is a technique of collecting an additional signal called a navigator, calculating the amount of body movement or organ movement of the subject from the additional signal, and finely adjusting the imaging position of the next continuous collection to substantially reduce the influence of movement. However, the pulse sequence of the target imaging is designed under conditions tuned to obtain a desired signal-to-noise ratio (SNR) and contrast. Therefore, when trying to collect a navigator signal, the target imaging and the collection of the navigator signal are executed alternately, and the simultaneity of the signal acquisition timing decreases.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems 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 shorten the overall imaging time and improve the image quality. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problems. It is also possible to position the problems corresponding to the respective effects of each configuration shown in the embodiments described later as other problems.

Means for Solving the Problems

[0005] The magnetic resonance imaging apparatus according to the embodiment includes a design unit and a collection unit. The design unit designs a pulse sequence for slice positions regarding a first slice group including a plurality of slices for multi-slice imaging by multi-section simultaneous excitation and a slice for navigator echo. The collection unit simultaneously excites the first slice group and the slice for navigator echo based on the pulse sequence and collects echo signals.

Brief Description of the Drawings

[0006]

Figure 1

Figure 2

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Figure 4

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Figure 8

Embodiments for Carrying Out the Invention

[0007] Hereinafter, embodiments of a magnetic resonance imaging apparatus, an imaging method, and an imaging program will be described in detail with reference to the drawings. In the following embodiments, parts denoted by the same reference numerals perform the same operations, and overlapping descriptions will be omitted as appropriate. Hereinafter, one embodiment will be described with reference to the drawings.

[0008] FIG. 1 is a block diagram showing a configuration example of a magnetic resonance imaging apparatus 1 according to the present embodiment. As shown in FIG. 1, the magnetic resonance imaging apparatus 1 includes a gantry 11, a bed 13, a gradient magnetic field power supply 21, a transmission circuit 23, a reception circuit 25, a bed driving device 27, a sequence control circuit 29, and a host computer 50.

[0009] The gantry 11 has a static magnetic field magnet 41 and a gradient magnetic field coil 43. The static magnetic field magnet 41 and the gradient magnetic field coil 43 are housed in the housing of the gantry 11. A bore having a hollow shape is formed in the housing of the gantry 11. A transmission coil 45 and a reception coil 47 are arranged in the bore of the gantry 11.

[0010] The static magnetic field magnet 41 has a hollow substantially cylindrical shape and generates a static magnetic field inside the substantially cylinder. As the static magnetic field magnet 41, for example, a permanent magnet, a superconducting magnet, or a normal conducting magnet is used. Here, the central axis of the static magnetic field magnet 41 is defined as the Z axis, the axis perpendicular to the Z axis vertically is defined as the Y axis, and the axis perpendicular to the Z axis horizontally is defined as the X axis. The X axis, Y axis, and Z axis constitute an orthogonal three-dimensional coordinate system.

[0011] The gradient magnetic field coil 43 is attached inside the static magnetic field magnet 41 and is a coil unit formed in a hollow substantially cylindrical shape. The gradient magnetic field coil 43 generates a gradient magnetic field upon receiving the supply of current from the gradient magnetic field power supply 21. More specifically, the gradient magnetic field coil 43 has three coils corresponding to the X-axis, Y-axis, and Z-axis that are orthogonal to each other. The three coils form a gradient magnetic field in which the magnetic field strength changes along each of the X-axis, Y-axis, and Z-axis. The gradient magnetic fields along the X-axis, Y-axis, and Z-axis are combined to form a frequency-encoding gradient magnetic field Gr, a phase-encoding gradient magnetic field Gp, and a slice-selection gradient magnetic field Gs that are orthogonal to each other in a desired direction. The frequency-encoding gradient magnetic field Gr is used to change the frequency of the magnetic resonance signal (MR signal) according to the spatial position. The phase-encoding gradient magnetic field Gp is used to change the phase of the MR signal according to the spatial position. The slice-selection gradient magnetic field Gs is used to arbitrarily determine the imaging section (slice). In the following description, it is assumed that the gradient direction of the frequency-encoding gradient magnetic field Gr is the X-axis, the gradient direction of the phase-encoding gradient magnetic field Gp is the Y-axis, and the gradient direction of the slice-selection gradient magnetic field Gs is the Z-axis.

[0012] The gradient magnetic field power supply 21 supplies current to the gradient magnetic field coil 43 in accordance with the sequence control signal from the sequence control circuit 29. By supplying current to the gradient magnetic field coil 43, the gradient magnetic field power supply 21 causes the gradient magnetic field coil 43 to generate a gradient magnetic field along each of the X-axis, Y-axis, and Z-axis. The gradient magnetic field is superimposed on the static magnetic field formed by the static magnetic field magnet 41 and applied to the subject P.

[0013] The transmission coil 45 is disposed, for example, inside the gradient magnetic field coil 43 and generates a high-frequency pulse (hereinafter referred to as an RF pulse) upon receiving the supply of current from the transmission circuit 23.

[0014] The transmission circuit 23 supplies a current to the transmission coil 45 in order to apply an RF pulse for exciting target protons existing in the subject P to the subject P via the transmission coil 45. The RF pulse vibrates at the resonance frequency specific to the target protons and excites the target protons. An MR signal is generated from the excited target protons and detected by the reception coil 47. The transmission coil 45 is, for example, a whole-body coil (WB coil). The whole-body coil may be used as a transmit-receive coil.

[0015] The reception coil 47 receives the MR signal emitted from the target protons existing in the subject P under the action of the RF pulse. The reception coil 47 has a plurality of reception coil elements capable of receiving the MR signal. The received MR signal is supplied to the reception circuit 25 via wire or wirelessly. Although not shown in FIG. 1, the reception coil 47 has a plurality of reception channels mounted in parallel. The reception channel has a reception coil element for receiving the MR signal, an amplifier for amplifying the MR signal, and the like. The MR signal is output for each reception channel. The total number of reception channels may be the same as the total number of reception coil elements, or may be more or less than the total number of reception coil elements.

[0016] The reception circuit 25 receives the MR signal generated from the excited target protons via the reception coil 47. The reception circuit 25 processes the received MR signal to generate a digital MR signal. The digital MR signal can be represented in the k-space defined by the spatial frequency. Therefore, hereinafter, the digital MR signal will be referred to as k-space data.

[0017] Note that the above transmission coil 45 and reception coil 47 are merely examples. Instead of the transmission coil 45 and the reception coil 47, a transmit-receive coil having a transmission function and a reception function may be used. Also, the transmission coil 45, the reception coil 47, and the transmit-receive coil may be combined.

[0018] A bed 13 is installed adjacent to the gantry 11. The bed 13 has a top plate 131 and a base 133. The subject P is placed on the top plate 131. The base 133 supports the top plate 131 so as to be slidable along the X-axis, Y-axis, and Z-axis respectively. A bed driving device 27 is housed in the base 133. The bed driving device 27 moves the top plate 131 under the control from the sequence control circuit 29. The bed driving device 27 may include any motor such as a servo motor or a stepping motor, for example.

[0019] The sequence control circuit 29 synchronously controls the gradient magnetic field power supply 21, the transmission circuit 23, and the reception circuit 25 based on the data collection conditions set by the design function 511 of the processing circuit 51, and subjects the subject P to data collection according to the data collection conditions to collect k-space data regarding the subject P. The data collection conditions define, for example, a pulse sequence, the magnitude of the current supplied to the gradient magnetic field coil 43 by the gradient magnetic field power supply 21, the timing at which the current is supplied to the gradient magnetic field coil 43 by the gradient magnetic field power supply 21, the magnitude of the RF pulse supplied to the transmission coil 45 by the transmission circuit 23, the timing at which the RF pulse is supplied to the transmission coil 45 by the transmission circuit 23, the timing at which the MR signal is received by the reception coil 47, and the like.

[0020] As shown in FIG. 1, the host computer 50 is a computer having a processing circuit 51, a memory 53, a display 55, an input interface 57, and a communication interface 59.

[0021] The processing circuit 51 has a processor such as a CPU as a hardware resource. The processing circuit 51 functions as the center of the magnetic resonance imaging apparatus 1. For example, the processing circuit 51 realizes a design function 511, a collection function 512, a correction function 513, an image generation function 514, and a determination function 515 by executing various programs.

[0022] The processing circuit 51 designs data collection conditions for the slice positions regarding a first slice group including a plurality of slices for multi-slice imaging by simultaneous multi-band slice (SMS) and a slice for navigator echoes, according to the design function 511. For example, the processing circuit 51 designs a pulse sequence including RF pulses for simultaneous multi-band excitation, the magnitude of the gradient magnetic field, the application timing, etc., according to the design function 511. A navigator echo is an echo signal used in a technique for performing motion correction and synchronization using an MR signal obtained from a moving organ.

[0023] Based on the pulse sequence designed by the design function 511, the processing circuit 51 simultaneously excites the first slice group and the slice for navigator echoes (also called navigator slices) and collects echo signals, according to the collection function 512. Based on the navigator echo, the processing circuit 51 performs motion correction according to the correction function 513.

[0024] The processing circuit 51 performs multi-slice separation and reconstruction processing on the echo signals collected by the collection function 512 and generates a reconstructed image, according to the image generation function 514. The processing circuit 51 performs various determinations according to the determination function 515. Also, the processing circuit 51 determines the cardiac cycle or the respiratory cycle using the navigator echo, according to the determination function 515.

[0025] The memory 53 is a storage device such as an HDD (Hard Disk Drive), an SSD (Solid State Drive), or an integrated circuit memory device that stores various information. Also, the memory 53 may be a drive device that reads and writes various information to and from portable storage media such as a CD-ROM drive, a DVD drive, or a flash memory. For example, the memory 53 stores data collection conditions, echo signals, navigator echoes, reconstructed images, control programs, etc.

[0026] The display 55 displays various information. As the display 55, for example, a CRT display, a liquid crystal display, an organic EL display, an LED display, a plasma display, or any other display known in the art can be appropriately used.

[0027] The input interface 57 includes an input device that receives various commands from the user. As the input device, a keyboard, a mouse, various switches, a touch screen, a touch pad, etc. can be used. Note that the input device is not limited to those having physical operation parts 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 magnetic resonance imaging apparatus 1 and outputs the received electrical signal to various circuits is also included in the example of the input interface 57. Further, the input interface 57 may be a voice recognition device that converts a voice signal collected by a microphone into an instruction signal.

[0028] The communication interface 59 is an interface that connects the magnetic resonance imaging apparatus 1 to a workstation, a PACS (Picture Archiving and Communication System), an HIS (Hospital Information System), an RIS (Radiology Information System), etc. via a LAN (Local Area Network) or the like. The communication interface 59 transmits and receives various information between the connected workstation, PACS, HIS, and RIS.

[0029] Next, a first operation example of the magnetic resonance imaging apparatus according to the present embodiment will be described with reference to the flowchart of FIG. 2. In step SA1, the processing circuit 51 designs a pulse sequence for multi-slice simultaneous excitation by the design function 511. Specifically, it designs a composite RF pulse for exciting frequencies corresponding to the slice positions of a slice group (also referred to as target slices) related to multi-slice simultaneous excitation and navigator slices for navigator echoes, and a corresponding gradient magnetic field. Since the design method of the pulse sequence may use the design method used in multi-slice simultaneous excitation technology, the description here is omitted.

[0030] In step SA2, the processing circuit 51 simultaneously excites the target slices and navigator slices related to multi-slice simultaneous excitation and collects echo signals by the collection function 512. Specifically, the processing circuit 51 may drive the gradient magnetic field coil 43 and the transmission coil 45 via the sequence control circuit 29 by the collection function 512 to collect echo signals in accordance with the data collection conditions based on the pulse sequence.

[0031] In step SA3, the processing circuit 51 executes a multi-slice separation and reconstruction process on the echo signals corresponding to each slice by the image generation function 514 to generate a reconstructed image. The multi-slice separation and reconstruction process may use an image reconstruction process applying parallel imaging (PI) technology. That is, since the echo signals obtained by excitation with the composite RF pulse are in a state where the echo signals of each slice overlap, when imaged, an MR image in which the signals of each slice are superimposed is obtained. Therefore, an MR image corresponding to each slice may be generated by applying, for example, techniques such as GRAPPA (Genealized Autocalibrating Partially Parallel Acauisition) and CAIPIRINHA (Controlled Aliasing in Parallel Imaging Results in Higher Acceleration) in the slice direction so as to separate the images corresponding to each slice.

[0032] In step SA4, the determination function 515 causes the processing circuit 51 to determine whether to image the next slice group. For example, if the design function 511 has designed an RF pulse and a gradient magnetic field for the slice group for multi-slice simultaneous excitation at the next slice position as data collection conditions, it may be determined to image the next slice group. If it is determined to image the next slice group, return to step SA2 and repeat the same process. On the other hand, if it is not determined to image the next slice group, end the process.

[0033] Note that as a process after step SA3, the correction function 513 may cause the processing circuit 51 to perform image processing on the echo signal corresponding to the target slice based on the navigator echo (OP1 in FIG. 2). Specifically, the correction function 513 causes the processing circuit 51 to separate the navigator echo corresponding to the navigator slice from the echo signal in which slices are simultaneously excited and the echo signals for each slice are combined. Based on the separated navigator echo, synchronization or correction, or both, for body movement or pulsation due to breathing or the like with respect to the reconstructed image is performed. The image processing OP1 may further execute a function of analyzing signal fluctuations after synchronization or correction.

[0034] Next, a second operation example of the magnetic resonance imaging apparatus according to the present embodiment will be described with reference to the flowchart of FIG. 3.

[0035] In step SB1, similarly to step SA1, the design function 511 causes the processing circuit 51 to design a pulse sequence for multi-slice simultaneous excitation. In step SB2, it is determined whether a navigator echo was acquired in the immediately preceding imaging. If a navigator echo was acquired, proceed to step SB3; if a navigator echo was not acquired, proceed to step SB6.

[0036] In step SB3, the collection function 512 causes the processing circuit 51 to excite the slice group and collect echo signals. In step SB4, similarly to step SA3, the processing circuit 51 executes a multi-slice separation and reconstruction process on the echo signals corresponding to each slice by the image generation function 514, and generates a reconstructed image.

[0037] In step SB5, the processing circuit 51 determines whether to image the next slice group by the determination function 515. If imaging the next slice group, it returns to step SB2 and repeats the same process. On the other hand, if not imaging the next slice group, the process ends. After step SB4 or step SB5, image processing corresponding to OP1 in FIG. 2 may be executed. In step SB6, since the navigator echo was not acquired in the immediately preceding imaging, the processing circuit 51 simultaneously excites the target slice and the navigator slice for multi-slice simultaneous excitation by the collection function 512, and collects the echo signals.

[0038] Note that in step SB2, if YES, that is, if the navigator echo was acquired in the immediately preceding imaging, the processing circuit 51 may correct the slice positions of the slice group for the next multi-slice imaging by multi-slice simultaneous excitation based on the navigator echo by the correction function 513 (OP2 in FIG. 3). Specifically, the processing circuit 51 may execute operations such as rearrangement of the echo signals and selection of data used for the reconstruction process in step SB4 on the echo signals corresponding to the target slice by the correction function 513.

[0039] Similarly, as the processing after step SB6, motion correction for the echo signals may be executed based on the navigator echo (OP3 in FIG. 3). In this way, the slice positions of the slice group related to the next imaging may be corrected based on the navigator echo collected immediately before.

[0040] Next, a first setting example of the imaging slice according to this embodiment will be described with reference to FIG. 4. FIG. 4 is a diagram showing the positional relationship of slices in the case of performing volume two-dimensional imaging such as functional magnetic resonance imaging (fMRI). This is an example of imaging a range corresponding to the whole brain in the imaging of the first set and the second set of multi-slices of multi-slice simultaneous excitation. Continuous imaging is performed by alternately repeating the imaging of the first set and the imaging of the second set.

[0041] FIG. 4 is a sagittal cross-section of the head of the subject P, and target slices 31 corresponding to each of a plurality of slices to be imaged used in multi-slice simultaneous excitation are set. Here, it is assumed that three different target slices 31 are simultaneously excited, but the number of simultaneously excited slice positions may be two or more. Further, the position of the navigator slice 32 is set in the gap between adjacent target slices 31. Note that the navigator slice 32 is not limited to the position of the lower gap between the target slices 31 as shown in FIG. 4, and may be set at the position of the upper gap.

[0042] Also, in the example of FIG. 4, an example is shown in which the navigator slice 32 and the target slices 31 are arranged without overlapping and without a gap in the body axis direction (slice direction), but the present invention is not limited to this. For example, a part of the navigator slice 32 and an adjacent target slice 31 may overlap, or a gap may be provided between the navigator slice 32 and an adjacent target slice 31. The positional relationship between the slices of the first set and the second set is such that the slice position of the second set is set higher overall compared to the slice position of the first set. Note that the positional relationship of the slice positions for each imaging is not particularly limited, and the same slice position may be continuously imaged.

[0043] Next, a second setting example of the imaging slice according to the present embodiment will be described with reference to FIG. 5. FIG. 5 shows the positional relationship of slices when two-dimensional multi-slice imaging in multi-slice simultaneous excitation is continuously or intermittently repeated and collected.

[0044] The first set and the second set of FIG. 5 are diagrams showing the slice positions in the case of imaging the chest of the subject P. Two target slices 31 related to multi-slice simultaneous excitation are set, and a navigator slice 32 is set in the gap between the two target slices 31. Here, although it is assumed that imaging is repeated at the same slice position, the position of the target slice 31 may be varied for each imaging.

[0045] When the two-dimensional multi-slice imaging is gradient echo imaging, for example, the processing circuit 51 by the design function 511 sets the flip angle of the navigator slice 32 to be larger than the flip angle of the slice group related to the multi-slice simultaneous excitation (that is, the target slice 31). Thereby, the blood flow signal collected from the navigator slice 32 becomes larger than the blood flow signal collected from the target slice 31. Therefore, since the blood flow signal corresponding to the navigator slice becomes easier to see, the processing circuit 51 can determine the cardiac cycle based on the navigator echo by the determination function 515.

[0046] On the other hand, when the processing circuit 51 sets the flip angle of the navigator slice 32 to be smaller than the flip angle of the target slice 31 by the design function 511, the echo signal collected from the slice position of the navigator slice 32 becomes smaller than the echo signal corresponding to the target slice 31. Therefore, the processing circuit 51 can determine the respiratory cycle based on the navigator echo by the determination function 515.

[0047] Next, a third setting example of the imaging slice according to the present embodiment will be described with reference to FIG. 6. FIG. 6 is a case of imaging the chest of the subject P as in FIG. 5, but the slice position of the target slice 31 in the repeated imaging is different from that in FIG. 5.

[0048] In the first set, the target slice 31 and the navigator slice 32 used for one image reconstruction are simultaneously excited. In the second set, the target slice 31 and the navigator slice 32 are simultaneously excited such that the position of the target slice 31 in the first set is symmetric with respect to the navigator slice 32. Here, an example of simultaneously exciting one target slice 31 and the navigator slice 32 is shown, but a plurality of target slices 31 may also be used.

[0049] In this way, in each imaging during repeated imaging, the target slice 31 that becomes part of the slice group for multi-slice simultaneous excitation and the navigator slice 32 may be simultaneously excited while switching a part of the target slice 31 for multi-slice simultaneous excitation.

[0050] Next, a fourth setting example of the imaging slice according to the present embodiment will be described with reference to FIG. 7. FIG. 7 is different from FIGS. 5 and 6 in that two types of navigator slices are simultaneously excited. As shown in the first set and the second set of FIG. 7, in repeated imaging, a navigator slice 61 for determining the cardiac cycle and a navigator slice 62 for determining the respiratory cycle are simultaneously excited together with a plurality of target slices 31 for multi-slice simultaneous excitation.

[0051] The flip angle of the navigator slice 61 is set to be larger than the flip angle of the slice 31, and the flip angle of the navigator slice 62 is set to be smaller than the flip angle of the slice 31. It is assumed that the slice positions of the navigator slice 61 and the navigator slice 62 are arranged adjacent to and parallel to the target slice 31, but not limited thereto. As long as they are simultaneously excited and the navigators do not overlap, they may be arranged in any manner. Thereby, based on the two types of navigator echoes, both the cardiac cycle and the respiratory cycle can be determined in simultaneous excitation.

[0052] Next, a fifth setting example of the imaging slice according to the present embodiment will be described with reference to FIG. 8. FIG. 8 shows an example of collecting a navigator echo during intermittent acquisition by transient GRE (Gradient Echo), which is a modified example of Fourier Decomposition (abbreviated as FD) or PREFUL (Phase-Resolved Functional Lung) (collectively referred to as the FD method hereinafter).

[0053] The FD method is ventilation / perfusion imaging by MRI that can non-invasively perform a respiratory function test instead of lung scintigraphy. The FD method has the merit of being able to be performed without contrast and under free breathing.

[0054] First, in the first set, an echo signal corresponding to the target slice 81 is collected. In the second set, a navigator echo corresponding to the navigator slice 32 is collected. In the third set, an echo signal corresponding to the same target slice 81 as the first set is collected. In this way, while intermittently collecting the echo signal corresponding to the target slice 81 (between the first set and the third set in FIG. 8), a navigator echo corresponding to the navigator slice 32 is collected. Similarly, while intermittently collecting the echo signal corresponding to the target slice 82, which is a slice position different from the target slice 81 (between the Nth set and the (N + 2)th set), a navigator echo corresponding to the navigator slice 32 is collected.

[0055] The collection of the navigator echo related to the navigator slice 32 is collected by Low-Flip GRE with a small flip angle. Thereby, the influence on the blood flow signal can be reduced, and intermittent acquisition at the same slice position can be performed.

[0056] According to the present embodiment described above, a navigator slice is set between a plurality of target slices related to multi-slice imaging by multi-section simultaneous excitation, and the target slice and the navigator slice are simultaneously excited. In this way, by simultaneously exciting the slices of the multi-section simultaneous excitation and the navigator slice to collect the echo signals, the imaging time can be shortened as compared with the case where the navigator echo is collected separately from the slices of the multi-section simultaneous excitation. Further, since the navigator slice for the navigator echo and the slices of the multi-section simultaneous excitation can be collected at the same timing, the influence of body movement can be effectively reduced. As a result, the time required for the entire imaging can be shortened and the image quality of the MR image corresponding to the target slice can be improved.

[0057] The term "processor" used in the above description means, for example, a CPU, a GPU, or a circuit such as an application specific integrated circuit (ASIC), a programmable logic device (for example, a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA)). The processor realizes its function by reading and executing a program stored in the storage circuit. Instead of storing the program in the storage circuit, the program may be directly incorporated into the circuit of the processor. In this case, the processor realizes its function by reading and executing the program incorporated in the circuit. Further, instead of executing the program, the function corresponding to the program may be realized by a combination of logic circuits. Each processor of the present embodiment is not limited to the case where it is configured as a single circuit for each processor, and a plurality of independent circuits may be combined to form one processor to realize its function. Furthermore, a plurality of components may be integrated into one processor to realize its function.

[0058] Although some embodiments have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations of embodiments can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, as well as in the invention described in the claims and the equivalent scope thereof.

[0059] Regarding the above embodiments, the following appendices are disclosed as one aspect and selective features of the invention. (Appendix 1) A design unit that designs a pulse sequence for slice positions related to a first slice group including a plurality of slices for multi-slice imaging by multi-section simultaneous excitation and a slice for a navigator echo, A collection unit that simultaneously excites the first slice group and the slice for the navigator echo based on the pulse sequence and collects echo signals, A magnetic resonance imaging apparatus comprising:

[0060] (Appendix 2) A correction unit that performs motion correction on the echo signal based on the navigator echo, The apparatus may further include an image generation unit that performs multi-section separation reconstruction processing on the echo signal on which the motion correction has been performed and generates a reconstructed image.

[0061] (Appendix 3) The correction unit may correct the slice positions of a second slice group including a plurality of slices for multi-slice imaging by multi-section simultaneous excitation, which is the next imaging of the first slice group, based on the navigator echo.

[0062] (Appendix 4) The design unit may design the slice for the navigator echo to be located in the gap between adjacent slices of the first slice group.

[0063] (Appendix 5) The design unit further designs a pulse sequence corresponding to the slice positions of a second slice group including a plurality of slices for multi-slice imaging by multi-slice simultaneous excitation, which is the next imaging of the first slice group, and the slice for the navigator echo. The acquisition unit may simultaneously excite the second slice group and the slice for the navigator echo based on the pulse sequence for the second slice group designed by the design unit, and collect echo signals.

[0064] (Appendix 6) The design unit designs a flip angle for the slice for the navigator echo to be larger than the flip angle for each slice of the first slice group. It may further include a determination unit that determines the cardiac cycle using the navigator echo.

[0065] (Appendix 7) The design unit designs a flip angle for the slice for the navigator echo to be smaller than the flip angle for each slice of the first slice group. It may further include a determination unit that determines the respiratory cycle using the navigator echo.

[0066] (Appendix 8) In the intermittent acquisition by the gradient echo in Fourier Decomposition or PREFUL (Phase-Resolved Functional Lung), during the intermittent acquisition, an acquisition unit that excites the slice for the navigator echo and collects echo signals, A determination unit that determines the cardiac cycle or the respiratory cycle based on the navigator echo, A magnetic resonance imaging apparatus comprising the same.

[0067] (Appendix 9) An image generation unit that performs multi-slice separation and reconstruction processing on the echo signal to generate a reconstructed image. Based on the navigator echo, a correction unit that performs image processing on the reconstructed image may be further included.

[0068] (Appendix 10) As the image processing, the correction unit may perform at least one of synchronization processing for body movement and pulsation, correction processing for the body movement and the pulsation, and analysis processing for signal fluctuations after the synchronization processing or the correction processing.

[0069] (Appendix 11) Design a pulse sequence for slice positions related to a first slice group including a plurality of slices for multi-slice imaging by multi-section simultaneous excitation and a slice for navigator echo, Based on the pulse sequence, simultaneously excite the first slice group and the slice for navigator echo, and collect echo signals. Imaging method.

[0070] (Appendix 12) Perform multi-section separation and reconstruction processing on the echo signals to generate a reconstructed image, Based on the navigator echo, image processing may be performed on the reconstructed image.

[0071] (Appendix 13) As the image processing, at least one of synchronization processing for body movement and pulsation, correction processing for the body movement and the pulsation, and analysis processing for signal fluctuations after the synchronization processing or the correction processing may be performed.

[0072] (Appendix 14) On a computer, A design function for designing a pulse sequence for slice positions related to a first slice group including a plurality of slices for multi-slice imaging by multi-section simultaneous excitation and a slice for navigator echo, Based on the pulse sequence, realize a collection function of simultaneously exciting the first slice group and the slice for navigator echo and collecting echo signals. Imaging program

[0073] (Appendix 15) The computer is further caused to execute multi-section separation and reconstruction processing on the echo signal to generate a reconstructed image, and an image generation function; and a correction function that executes image processing on the reconstructed image based on the navigator echo may be further realized.

[0074] (Appendix 16) The correction function may execute, as the image processing, at least one of synchronization processing for body movement and pulsation, correction processing for the body movement and the pulsation, and analysis processing for signal fluctuations after the synchronization processing or the correction processing.

Explanation of reference numerals

[0075] 1 Magnetic resonance imaging apparatus 11 Gantry 13 Bed 21 Gradient magnetic field power supply 23 Transmission circuit 25 Reception circuit 27 Bed drive device 29 Sequence control circuit 31, 81, 82 Target slice 32, 61, 62 Navigator slice 41 Static magnetic field magnet 43 Gradient magnetic field coil 45 Transmission coil 47 Reception coil 50 Host computer 51 Processing circuit 53 Memory 55 Display 57 Input interface 59 Communication interface 131 Top plate 133 Base 511 Design function 512 Collection function 513 Correction function 514 Image generation function 515 Decision-making function

Claims

1. A design unit that designs a pulse sequence for slice positions related to a first slice group including a plurality of slices for multi-slice imaging by multi-section simultaneous excitation and a slice for navigator echo; A collection unit that simultaneously excites the first slice group and the slice for navigator echo based on the pulse sequence and collects echo signals; A magnetic resonance imaging apparatus comprising:

2. A correction unit that performs motion correction on the echo signals based on navigator echo; The magnetic resonance imaging apparatus according to claim 1, further comprising an image generation unit that performs multi-section separation and reconstruction processing on the echo signals on which the motion correction has been performed and generates a reconstructed image.

3. The correction unit corrects the slice positions of a second slice group including a plurality of slices for multi-slice imaging by multi-section simultaneous excitation, which is the next imaging of the first slice group, based on the navigator echo. The magnetic resonance imaging apparatus according to claim 2.

4. The design unit designs the slice for navigator echo to be located in the gap between adjacent slices of the first slice group. The magnetic resonance imaging apparatus according to claim 1.

5. The design unit further designs a pulse sequence corresponding to the slice positions of a second slice group including a plurality of slices for multi-slice imaging by multi-section simultaneous excitation, which is the next imaging of the first slice group, and a slice for navigator echo. The collection unit simultaneously excites the second slice group and the slice for navigator echo based on the pulse sequence related to the second slice group designed by the design unit and collects echo signals. The magnetic resonance imaging apparatus according to claim 1.

6. The design unit designs the flip angle related to the slice for navigator echo to be larger than the flip angle related to each slice of the first slice group. The magnetic resonance imaging apparatus according to claim 1, further comprising a determination unit that determines the cardiac cycle using the navigator echo.

7. The design unit designs the flip angle related to the slice for navigator echo to be smaller than the flip angle related to each slice of the first slice group. The magnetic resonance imaging apparatus according to claim 1, further comprising a determination unit that determines a respiratory cycle using the navigator echo.

8. In the intermittent acquisition by the gradient echo in Fourier Decomposition or PREFUL (Phase-Resolved Functional Lung), a collection unit that excites a slice for the navigator echo and collects an echo signal during the intermittent acquisition; A determination unit that determines a cardiac cycle or a respiratory cycle based on the navigator echo; A magnetic resonance imaging apparatus comprising:

9. An image generation unit that performs multi-slice separation reconstruction processing on the echo signal to generate a reconstructed image; The magnetic resonance imaging apparatus according to claim 1, further comprising a correction unit that performs image processing on the reconstructed image based on the navigator echo.

10. The correction unit performs, as the image processing, at least one of synchronization processing for body movement and pulsation, correction processing for the body movement and the pulsation, and analysis processing for signal fluctuations after the synchronization processing or the correction processing. The magnetic resonance imaging apparatus according to claim 9.

11. Design a pulse sequence for the slice positions related to a first slice group including a plurality of slices for multi-slice imaging by multi-slice simultaneous excitation and a slice for the navigator echo. Based on the pulse sequence, simultaneously excite the first slice group and the slice for the navigator echo, and collect an echo signal. Imaging method.

12. Perform multi-slice separation reconstruction processing on the echo signal to generate a reconstructed image, Perform image processing on the reconstructed image based on the navigator echo. The imaging method according to claim 11.

13. As the image processing, perform at least one of synchronization processing for body movement and pulsation, correction processing for the body movement and the pulsation, and analysis processing for signal fluctuations after the synchronization processing or the correction processing. The imaging method according to claim 12.

14. On a computer, A design function for designing a pulse sequence for the slice positions related to a first slice group including a plurality of slices for multi-slice imaging by multi-slice simultaneous excitation and a slice for the navigator echo. Based on the pulse sequence, a collection function is realized to simultaneously excite the first slice group and the slice for navigator echo and collect echo signals. Imaging program.

15. On the computer, An image generation function is realized to perform multi-slice separation reconstruction processing on the echo signal and generate a reconstructed image. The imaging program according to claim 14, further realizing a correction function to perform image processing on the reconstructed image based on the navigator echo.

16. The correction function, as the image processing, executes at least one of synchronization processing for body movement and pulsation, correction processing for the body movement and the pulsation, and analysis processing for signal fluctuations after the synchronization processing or the correction processing. The imaging program according to claim 15.

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