JP6242786B2 - Magnetic resonance imaging system - Google Patents

Description

Embodiments described herein relate generally to a magnetic resonance imaging apparatus (hereinafter abbreviated as an MRI apparatus as appropriate) and a magnetic resonance imaging method.
The embodiment of the present invention also relates to a technique for applying a pre-pulse such as a pre-saturation pulse for saturating nuclear spins in an application region or an inversion recovery pulse (hereinafter referred to as an IR pulse).

  MRI (Magnetic Resonance Imaging) magnetically excites a subject's nuclear spin placed in a static magnetic field with a Larmor frequency radio frequency pulse (hereinafter referred to as an RF pulse), and is generated along with this excitation. This is an imaging method for reconstructing an image from a nuclear magnetic resonance signal (hereinafter referred to as an MR signal).

  In an image captured by MRI, motion artifacts (motion artifacts) caused by movement of body tissue regardless of voluntary or nonvoluntary may occur. For periodic motion such as pulsation of blood vessels, it may appear as a ghost in a certain direction (phase encoding direction) depending on imaging conditions. For non-periodic movements such as swallowing and breathing, it may appear as parallel stripes in a certain direction (phase encoding direction) or image blur. These artifacts can be mistaken for lesions and can be an obstacle to accurate diagnosis.

  Therefore, in normal MRI imaging, by applying a presaturation pulse to a specific region prior to the application of an excitation pulse for data acquisition of MR signals, an MR signal from a site where body movement causing artifacts is generated. Suppressing and improving image quality.

  Patent document 1 is known as a prior art regarding this presaturation pulse. The MRI apparatus described in Patent Document 1 displays the application purpose and application effect of each prepulse when setting imaging conditions, and determines the application order when a plurality of prepulses are applied.

  In determining the application order, it is considered that the presaturation pulse applied last has a larger signal suppression effect than the presaturation pulse applied before that. This facilitates the setting of a plurality of prepulses having various purposes such as water excitation and fat suppression.

JP 2008-289862 A

  Patent Document 1 has an excellent effect as described above. However, in actual imaging, there are many imaging conditions to be set in addition to the order of applying prepulses. Specifically, in addition to the original imaging conditions of the region of interest, the operator also sets prepulse imaging conditions for the purpose of improving image quality such as artifact reduction. For example, in spine imaging, body motion artifacts occur due to abdominal body movements due to breathing and pulsation of the cardiac large blood vessels in front of the spine, so it is time-consuming to set a presaturation pulse application area to reduce these body movement artifacts. Occurs.

  In addition, the MRI apparatus can separate and image arteries and veins by using a technique such as t-SLIP (Time Spatial Labeling Inversion Pulse), which is useful for diagnosis of renal arteries and the like. Has been. However, the imaging conditions are complicated because it is necessary to combine a plurality of prepulse application areas such as area selective IR pulses and presaturation pulses applied as labeling pulses together with imaging positioning.

  For this reason, there has been a demand for a technique that makes it easier to set imaging conditions related to prepulses than in the past.

  An MRI apparatus according to an embodiment includes a first imaging unit, a first image generation unit, a calculation unit, a second imaging unit, and a second image generation unit.

The first imaging unit executes a first imaging sequence.
The first image generation unit generates first image data using an MR signal obtained by executing the first imaging sequence.
The calculation unit calculates an application region of a prepulse applied in a second imaging sequence different from the first imaging sequence, based on the first image data.

The second imaging unit executes the second imaging sequence with the application of the prepulse whose application region has been calculated by the calculation unit.
The second image generation unit generates second image data using the MR signal obtained by executing the second imaging sequence.

The block diagram which shows the structure of the MRI apparatus in 1st Embodiment. FIG. 2 is a functional block diagram showing details of the computer of FIG. The schematic diagram which shows the Coronal cross-sectional image as an example of the positioning image used at the time of imaging | photography of the spine. The schematic diagram which shows the Sagital cross-sectional image as an example of the positioning image used at the time of imaging | photography of the spine. The schematic diagram which shows the Coronal cross-section image as an example of the boundary line information of a spine and a body surface. The schematic diagram which shows the Sagital cross-sectional image as an example of the boundary line information of a spine and a body surface. The schematic diagram which shows the calculation method of the application area | region of the presaturation pulse in 1st Embodiment. The flowchart which shows operation | movement of the MRI apparatus in 1st Embodiment. In 2nd Embodiment, the typical explanatory drawing which calculated | required the thickness of the application area | region of the presaturation pulse with respect to each Sagital cross-sectional image obtained by changing a respiratory phase by dynamic imaging | photography. 9 is a flowchart showing the operation of the MRI apparatus in the second embodiment. The block diagram which shows the structure of the MRI apparatus in 3rd Embodiment. The schematic diagram which shows the calculation method of the application area | region of IR pulse and a presaturation pulse in 4th Embodiment. The flowchart which shows operation | movement of the MRI apparatus in 4th Embodiment.

  Hereinafter, embodiments of an MRI apparatus and an MRI method will be described with reference to the accompanying drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same element and the overlapping description is abbreviate | omitted.

<First Embodiment>
The first embodiment relates to automating the setting of a presaturation pulse application region by taking “vertebral disc imaging” as an example.

  FIG. 1 is a block diagram showing the overall configuration of the MRI apparatus 20 in the first embodiment. As shown in FIG. 1, the MRI apparatus 20 includes a cylindrical static magnetic field magnet 22 for forming a static magnetic field, a cylindrical shim coil 24 provided with the same axis inside the static magnetic field magnet 22, A gradient magnetic field coil 26, an RF coil 28, a control system 30, and a bed 32 on which the subject P is placed are provided. Here, as an example, for the X axis, Y axis, and Z axis that are orthogonal to each other, the vertical direction will be described as the Y axis direction. The bed 32 is arranged so that the normal direction of the surface for placing the top plate is the Y-axis direction, and the axial direction of the static magnetic field magnet 22 and the shim coil 24 is the Z-axis direction. To do.

  The control system 30 includes a static magnetic field power supply 40, a shim coil power supply 42, a gradient magnetic field power supply 44, an RF transmitter 46, an RF receiver 48, a sequence controller 50, and a computer 52.

  The gradient magnetic field power supply 44 includes an X-axis gradient magnetic field power supply 44x, a Y-axis gradient magnetic field power supply 44y, and a Z-axis gradient magnetic field power supply 44z. The computer 52 includes an arithmetic device 60, an input device 62, a display device 64, and a storage device 66.

  The static magnetic field magnet 22 is connected to the static magnetic field power supply 40 and forms a static magnetic field in the imaging space by the current supplied from the static magnetic field power supply 40. The shim coil 24 is connected to a shim coil power source 42 and makes the static magnetic field uniform by a current supplied from the shim coil power source 42. The static magnetic field magnet 22 is often composed of a superconducting coil, and is connected to the static magnetic field power source 40 and supplied with current when excited, but after being excited, it is disconnected. Is common. The static magnetic field magnet 22 may be formed of a permanent magnet without providing the static magnetic field power supply 40.

  The gradient magnetic field coil 26 includes an X-axis gradient magnetic field coil 26 x, a Y-axis gradient magnetic field coil 26 y, and a Z-axis gradient magnetic field coil 26 z, and is formed in a cylindrical shape inside the static magnetic field magnet 22. The X axis gradient magnetic field coil 26x, the Y axis gradient magnetic field coil 26y, and the Z axis gradient magnetic field coil 26z are connected to the X axis gradient magnetic field power supply 44x, the Y axis gradient magnetic field power supply 44y, and the Z axis gradient magnetic field power supply 44z, respectively. Is done.

  The X-axis gradient magnetic field power supply 44x, the Y-axis gradient magnetic field power supply 44y, and the Z-axis gradient magnetic field power supply 44z respectively supply currents to the X-axis gradient magnetic field coil 26x, the Y-axis gradient magnetic field coil 26y, and the Z-axis gradient magnetic field coil 26z. A gradient magnetic field Gx in the X-axis direction, a gradient magnetic field Gy in the Y-axis direction, and a gradient magnetic field Gz in the Z-axis direction are formed in the imaging space.

  The RF transmitter 46 generates an RF pulse for causing nuclear magnetic resonance based on the control information input from the sequence controller 50, and transmits this to the RF coil 28 for transmission. The RF coil 28 includes a whole body coil (WBC) for receiving and transmitting RF pulses built in the gantry, a local coil for receiving RF pulses provided in the vicinity of the bed 32 or the subject P, and the like. is there.

  The transmission RF coil 28 receives an RF pulse from the RF transmitter 46 and transmits it to the subject P. The receiving RF coil 28 receives an MR signal generated by exciting a nuclear spin inside the subject P by an RF pulse, and this MR signal is detected by an RF receiver 48.

  The RF receiver 48 generates and generates raw data (raw data), which is digitized complex data, by performing predetermined signal processing and A / D (analog to digital) conversion on the detected MR signal. The raw data of the MR signal is input to the sequence controller 50.

  The arithmetic device 60 performs system control of the entire MRI apparatus 20, and will be described with reference to FIG.

  The sequence controller 50 stores control information necessary for driving the gradient magnetic field power supply 44, the RF transmitter 46, and the RF receiver 48 in accordance with a command from the arithmetic device 60. The control information here is, for example, sequence information describing operation control information such as the intensity, application time, and application timing of the pulse current to be applied to the gradient magnetic field power supply 44.

  The sequence controller 50 drives the gradient magnetic field power supply 44, the RF transmitter 46, and the RF receiver 48 according to the stored predetermined sequence, thereby causing the X axis gradient magnetic field Gx, the Y axis gradient magnetic field Gy, the Z axis gradient magnetic field Gz, and the RF. Generate a pulse. Further, the sequence controller 50 receives the raw data of the MR signal input from the RF receiver 48 and inputs this to the arithmetic device 60.

  FIG. 2 is a functional block diagram showing details of the computer 52 of FIG. As shown in FIG. 2, the arithmetic device 60 includes an MPU (Micro Processor Unit) 80, a condition storage unit 82, an imaging condition setting unit 84, an image processing condition setting unit 86, a display control unit 88, and an image reproduction unit. A configuration unit 90, an image processing unit 92, and a system bus 94 are provided.

  The MPU 80 performs system control of the entire MRI apparatus 20 via the system bus 94 in setting of imaging conditions, imaging operation, and image processing after imaging.

The input device 62 provides the operator with a function for setting imaging conditions and image processing conditions. Further, after determining the imaging conditions, the input device 62 inputs control instructions such as imaging start or imaging interruption input by the operator to the MPU 80.
The condition storage unit 82 stores imaging conditions and image processing conditions.

The imaging condition setting unit 84 acquires imaging conditions for past imaging from the condition storage unit 82 via the system bus 94, and accepts setting of imaging conditions by the operator via the input device 62. Further, the imaging condition setting unit 84 causes the condition storage unit 82 to store the imaging conditions changed by the operator's input.
Furthermore, the imaging condition setting unit 84 performs “pre-pulse region calculation processing” based on the result of “region extraction processing” performed by the image processing unit 92 described later. This is one of the major features of this embodiment, and this determines the presaturation pulse application region.
The above “region extraction processing” and “prepulse region calculation processing” will be described in detail in the description of FIG.

  The image processing condition setting unit 86 acquires past image processing conditions from the condition storage unit 82 via the system bus 94, and accepts setting of image processing conditions by the operator via the input device 62. Further, the image processing condition setting unit 86 causes the condition storage unit 82 to store the image processing conditions set by the operator's input.

  The image reconstruction unit 90 performs processing such as known two-dimensional Fourier transform on the MR signal raw data input from the sequence controller 50 to generate image data of MR images of each slice of the subject P. The image reconstruction unit 90 inputs the generated image data to the image processing unit 92.

  The image processing unit 92 performs image processing on the input image data in accordance with the image processing conditions stored in the condition storage unit 82, and stores the image data after the image processing in the storage device 66. In addition, the image processing unit 92 performs a region extraction process for extracting a region of a specific tissue in the body of the subject P such as an organ or a spine based on, for example, image data obtained by capturing a positioning image. This is also one of the major features of this embodiment.

  The storage device 66 functions as an image database. The image data generated by the image reconstruction unit 90 and then subjected to image processing by the image processing unit 92 and the imaging used to capture the MR image are stored. The conditions and patient information are stored in association with each other. Further, the storage device 66 transmits the image data to the image processing unit 92 and the display control unit 88 in accordance with an instruction from the MPU 80.

  The display control unit 88 causes the display device 64 to display the imaging conditions and image processing conditions stored in the condition storage unit 82, and causes the display device 64 to display the image data stored in the storage device 66 as an MR image. . The display control unit 88 causes the display device 64 to display the latest imaging conditions and image processing conditions when there is a change in the imaging conditions or image processing conditions stored in the condition storage unit 62.

  FIG. 3 is a schematic diagram showing a cross-sectional image of a coronal plane (Coronal Plane) as an example of a positioning image used when imaging a spine, and FIG. 4 is a sagittal shape as an example of a positioning image used when imaging a spine. It is a schematic diagram which shows the cross-sectional image of a surface (Sagittal Plane). 3 and 4, the outer square frame indicates the outer edges 100 and 102 of the imaging slice including the region of interest, the solid line portion on the inner side indicates the body surface boundary line 104 of the subject P, and the dotted line portion indicates the subject. An outline 106 of P body tissue is shown.

  FIG. 5 is a schematic diagram illustrating a Coronal cross-sectional image as an example of boundary information of the spine and body surface, and FIG. 6 is a schematic diagram illustrating a Sagittal cross-sectional image as an example of boundary information of the spine and body surface.

  In FIG. 5, the body surface boundary line 104 of the subject P is indicated by a solid line, and the contour 108 of the spine is indicated by a dotted line. In FIG. 6, the ventral body surface boundary line 120 and the back side body surface boundary line 122 are indicated by solid lines, and the ventral spine boundary line 124 and the back side spine boundary line 126 are indicated by dotted lines.

  FIG. 7 is a schematic diagram of a Sagital cross-sectional image showing a method for determining a pre-saturation pulse application region, which is (1) to (4) in chronological order of the determination method.

  FIG. 7 (1) shows after the boundary line between the spine and body surface is extracted, FIG. 7 (2) shows after the direction of application of the presaturation pulse is determined, and FIG. 7 (3) shows the ventral body surface boundary. FIG. 7 (4) shows after the determination of the thickness of the application region of the presaturation pulse.

  7 (1) to (4), the outermost square frame indicates the outer edge 116 of the positioning image displayed on the display device 64, and the square frame indicated by the thick solid line in FIGS. 7 (2) and 7 (3) , Shows the outer edge 128 of the imaging slice containing (positioned) the region of interest.

  In FIG. 7 (4), the outer edge 128 of the imaging slice is omitted because it is complicated and makes it difficult to see other elements. The meanings of the straight lines indicated by reference numerals 130, 132, 134, 136, and 138 in FIGS. 7 (2) to 7 (4) will be described as operations of the MRI apparatus 20 with reference to FIG.

  FIG. 8 is a flowchart showing the operation of the MRI apparatus 20 of the first embodiment. Hereinafter, the operation of the MRI apparatus 20 will be described according to the flowchart shown in FIG. 8 with reference to FIGS. 1, 2, and 5 to 7 as appropriate.

  [Step S1] An imaging purpose is designated by the operator via the input device 62 (see FIG. 1). In the present embodiment, as an example, “vertebral disc imaging” is designated.

  The imaging condition setting unit 84 (see FIG. 2) stores “spine” as the imaging condition in the condition storage unit 82, and acquires the imaging conditions used in the past as “vertebral disc imaging” from the condition storage unit 82. This is input to the display control unit 88. The display control unit 88 causes the display device 64 to display an example of imaging conditions used in the past as “vertebral disc imaging”.

  The operator can edit the imaging conditions by referring to the display contents, but if there is no input, the imaging condition setting unit 84 uses the Coronal section as an MR image (hereinafter referred to as a positioning image) used for positioning the imaging slice. An image and a Sagittal cross-sectional image are set to be captured. In this case, since “vertebral disc imaging” is designated as the imaging purpose, the Coronal cross-sectional image and the Sagittal cross-sectional image are generally more suitable for positioning than the Axial cross-sectional image (transverse cross section).

  [Step S2] When the operator gives an instruction to start imaging via the input device 62, the MRI apparatus 20 captures a positioning image. Thereby, the raw data of the MR signal is input from the sequence controller 50 to the image reconstruction unit 90, and the image reconstruction unit 90 performs processing such as two-dimensional Fourier transform on the raw data to generate the image data of the positioning image. This is input to the image processing unit 92. The image processing unit 92 performs predetermined image processing on the input image data in accordance with the image processing conditions stored in the condition storage unit 82, and temporarily stores the image data after the image processing in the storage device 66.

  [Step S3] The image processing unit 92 acquires the image data of the positioning image from the storage device 66, and performs region extraction processing for extracting the positions of the boundary lines of the spine and the body surface based on the image data.

  More specifically, the image processing unit 92 performs noise removal processing by, for example, a median filter or contraction processing (Erosion) on the image data of the Coronal cross-sectional image and the Sagittal cross-sectional image generated in step S2.

  Next, the image processing unit 92 obtains a mask image in which the air portion and the spine portion are extracted by performing threshold processing on the image data after noise removal. In general, air and bone regions in MR images contain few water atoms because they contain little water, so they appear as low-signal regions (black as MR images), so they can be distinguished from adjacent tissue regions. is there.

  Next, the image processing unit 92 regards an air mask image in which a portion connected to a low signal portion (black region) at the outer edge of the image is regarded as an air region, and a low signal portion other than the air region as a spine region. Create a spine mask image. Next, the image processing unit 92 performs edge extraction processing using a differential filter on the image data of the positioning image. The image processing unit 92 extracts the boundary line position of the spine by combining the edge extraction result with the air mask image and the spine mask image (see FIGS. 5 and 6).

  Further, the image processing unit 92 acquires the outer edge of the air mask image as a boundary line between air and body tissue, that is, a boundary line of the body surface. The image processing unit 92 stores the spine and body surface boundary line information extracted in this manner and inputs the information to the imaging condition setting unit 84.

  In addition, the image processing unit 92 performs a process of selecting a vertebra and an intervertebral disc based on the image data of the Coronal cross-sectional image and the Sagittal cross-sectional image for positioning the axial cross-sectional image.

  For this selection process, for example, conventional image processing such as performing a template matching with a captured image based on a standard human skeleton model including the shape and size of vertebrae and intervertebral discs may be used. The image processing unit 92 stores the boundary line information between the vertebrae and the intervertebral disc thus selected and inputs them to the imaging condition setting unit 84.

  [Step S4] The imaging condition setting unit 84 performs imaging positioning of the main scan. The imaging area of the sagittal section of the spine is positioned so that the FOV (Field Of View) is orthogonal to the positioning image of the Coronal section.

  The phase encoding direction in the imaging area of the sagittal section of the spine is set parallel to the extending direction of the spine extracted from the positioning image of the coronal section, and the direction from the foot to the head is set as the positive direction.

  In addition, the imaging condition setting unit 84 refers to the spine region extracted from the positioning image of the Sagittal cross section, and sets an FOV in which a margin set as an image processing condition is added to the spine region so as to cover the spine region. . The imaging condition setting unit 84 performs imaging so that a plurality of slices are imaged so that the center of the imaging slice passes through the center position of the extracted spine region in order to image a sagittal section passing through the center of the spine.

  Further, since the imaging condition setting unit 84 images the cross section of each intervertebral disc, the axial section of the intervertebral disc is aligned so that the center of the imaging slice matches the center of the intervertebral disc based on the boundary information of the vertebra and intervertebral disc acquired in step S3. The image is positioned and the number of slices is set to 3 for example.

  The above imaging condition setting result is stored in the condition storage unit 82 and displayed on the display device 64 by the display control unit 88. Note that the operator may manually adjust the imaging condition setting via the input device 62 as necessary.

  [Step S5] In steps S5 and S6, the imaging condition setting unit 84 performs a prepulse region calculation process. In this step S5, the direction of the presaturation pulse application region is calculated, and the thickness is calculated in the next step S6. . Note that the presaturation pulse in spine imaging has the purpose of reducing artifacts due to abdominal body movements.

  Specifically, the imaging condition setting unit 84 determines the ventral side in the Sagittal cross-sectional image based on the boundary information on the spine and body surface in the Sagittal cross-sectional image acquired in Step S3 and the information on the body posture direction with respect to the MR image. Identify the back side.

  This determines which of the two body surface boundary lines is the ventral body surface boundary line 120 (or back side body surface boundary line 122). Similarly, the ventral spine boundary line 124 and the back spine boundary line 126 are determined (see FIG. 7 (1)). Note that the information on the body posture direction with respect to the MR image can be acquired from the condition storage unit 82 because it is generally an imaging condition input at the time of imaging each MR image.

  Next, the imaging condition setting unit 84 calculates a straight line 130 that linearly approximates the ventral spine boundary line 124 inside the outer edge 128 of the imaging slice, as shown in FIG.

  For this linear approximation, for example, a known method such as applying the least square method after replacing the ventral spine boundary line 124 with a number of plots in the two-dimensional coordinate system may be used.

  Note that the portion of the ventral spinal boundary 124 that protrudes from the outer edge 128 of the imaging slice is not considered in the calculation of the straight line 130. The imaging condition setting unit 84 tentatively determines the direction of the straight line 130 as the direction of the application region of the presaturation pulse.

  [Step S6] In order to calculate the thickness of the pre-saturation pulse application region, the imaging condition setting unit 84 is parallel to the straight line 130 and is within the imaging slice range as shown in FIG. A straight line 132 circumscribing the lateral spine boundary line 124 from the ventral side is calculated.

  Next, as shown in FIG. 7 (3), the imaging condition setting unit 84 is parallel to the straight line 132 and is more than the abdomen with respect to the ventral body surface boundary line 120 in the outer edge 128 of the imaging slice. A straight line 134 that contacts from the outside is calculated. Note that the portion of the ventral body surface boundary line 120 that protrudes from the outer edge 128 of the imaging slice is not considered in the calculation of the straight line 134.

  Next, as shown in FIG. 7 (4), the imaging condition setting unit 84 is linear only by a margin (width from the spine boundary line to the application region end of the presaturation pulse) set as one of the image processing conditions. A straight line 136 (indicated by a one-dot chain line in the figure) obtained by translating 132 to the ventral side is calculated.

  Regarding this margin, an appropriate value (for example, 10 mm, 20 mm, 1/3 of the spine width, etc.) may be set in advance in consideration of the following two points. First, if the margin is too small, the MR signal from the spinal region that is the region of interest is also suppressed by the presaturation pulse when the subject P moves even a little. Second, if the margin is too large, the effect of suppressing body movement artifacts outside the region of interest will be reduced.

  Next, as shown in FIG. 7 (4), the imaging condition setting unit 84 sets the straight line 134 to the outside of the belly by the margin set as one of the image processing conditions (to the outer edge 128 side of the imaging slice). The translated straight line 138 (indicated by the alternate long and short dash line in the figure) is calculated. The margin here corresponds to the width from the end of the presaturation pulse application region to the ventral body surface boundary line 120.

  The distance between the straight line 136 and the straight line 138 is the thickness of the presaturation pulse region. That is, the imaging condition setting unit 84 tentatively determines an area between the straight lines 136 and 138 as a presaturation pulse application area, and stores the application area in the condition storage unit 82 as an imaging condition. The application region of the presaturation pulse automatically calculated in this way is displayed on the display device 64 by the display control unit 88 as shown in FIG.

  Here, the operator can change (adjust) the direction and width of the application region of the displayed presaturation pulse via the input device 62 as necessary. When there is no input from the operator regarding the application region of the presaturation pulse, the imaging condition setting unit 84 uses the application region automatically calculated as described above (provisionally determined) as the application region of the presaturation pulse. To decide.

  In addition, the automatically calculated application area may be automatically determined as the final application area without displaying the application area of the presaturation pulse automatically calculated as described above for confirmation by the operator.

  [Step S7] Imaging is performed according to the imaging conditions finally determined as described above. That is, after applying a presaturation pulse to a region sandwiched between straight lines 136 and 138, an RF pulse for collecting image data is applied, and an MR signal from the subject P is detected by the RF receiver 48.

  The sequence controller 50 inputs the raw data of the MR signal to the image reconstruction unit 90, and the image reconstruction unit 90 performs predetermined processing on the raw data to generate image data, which is then sent to the image processing unit 92. input.

The image processing unit 92 performs predetermined image processing on the input image data, and stores the image data after the image processing in the storage device 66. Further, the image data after the image processing is displayed on the display device 64 by the display control unit 88.
The above is the description of the operation of the MRI apparatus 20 of the first embodiment.

  As described above, in the first embodiment, the MRI apparatus 20 automatically calculates the imaging conditions related to the application region of the presaturation pulse for reducing body motion artifacts and flow artifacts. Thereby, the burden of setting the imaging conditions by the operator is reduced. As a result, the throughput of the inspection using the MRI apparatus 20 can be improved.

<Second Embodiment>
The second embodiment is the same as the first embodiment in that a presaturation pulse application region is automatically calculated in spinal disc imaging, but differs from the first embodiment in the following points.

  That is, in the second embodiment, each time-phase image data obtained by dynamic imaging (a method of performing a plurality of imaging with different time phases on the same cross section) is compared with the first embodiment. Similarly, straight lines 136 and 138 (corresponding to the presaturation pulse application region end) are calculated. A region between the straight lines 136 and 138 in the time-phase image data in which the interval between the straight lines 136 and 138 (corresponding to the thickness of the presaturation pulse application region) is maximum is set as a presaturation pulse application region (provisional). To determine).

  In the second embodiment, the apparatus configuration is the same as that of the MRI apparatus 20 of the first embodiment shown in FIGS. 1 and 2, and therefore the configuration diagram is omitted, and the agreement of the MRI apparatus is the same as that of the first embodiment. Also assume 20.

  FIG. 9 is a schematic diagram in which straight lines 136 and 138 are obtained for each of the Sagital cross-sectional images obtained by changing the respiratory phase by dynamic imaging, as in the first embodiment. Time t is shown.

  In this example, since the thickness of the abdomen becomes the maximum at time t1, the interval between the straight lines 136 and 138 corresponding to the thickness of the application region of the presaturation pulse also becomes the maximum value (d1), and the straight lines 136 and 138 at time t2. The case where the interval of becomes the minimum value (d2) is shown.

  FIG. 10 is a flowchart showing the operation of the MRI apparatus 20 in the second embodiment. Hereinafter, the operation of the MRI apparatus 20 of the second embodiment will be described according to the flowchart shown in FIG. 10 with a focus on differences from the first embodiment.

  [Step S1a] The operator specifies “vertebral disc imaging” as an imaging purpose via the input device 62 (see FIG. 2), and also detects “position change of the body surface due to body movement of the abdomen”. “Dynamic imaging” is designated.

  [Step S2a] When the operator instructs the start of imaging via the input device 62, the MRI apparatus 20 performs dynamic imaging of the positioning image. Then, the image reconstruction unit 90 generates image data of a plurality of time-positioned positioning images that have been imaged and inputs them to the image processing unit 92. The image processing unit 92 temporarily stores each image data after the image processing in the storage device 66.

  [Step S3a] The image processing unit 92 acquires image data of each MR image whose time phase has been changed from the storage device 66, and based on these image data, the same procedure as Step S3 of the first embodiment is performed. Extract the position of the border between the spine and body surface.

  The image processing unit 92 stores the extracted spine and body surface boundary line information and inputs the information to the imaging condition setting unit 84. In addition, the image processing unit 92 performs a vertebra and intervertebral disc selection process in the same procedure as in the first embodiment, stores boundary information about the vertebrae and the intervertebral disc, and inputs the information to the imaging condition setting unit 84.

  [Step S4a] The imaging condition setting unit 84 positions the imaging of the main scan in the same manner as in step S4 of the first embodiment.

  [Step S5a] The imaging condition setting unit 84 linearly approximates the ventral spinal boundary line 124 in the Sagittal cross-sectional image in the same manner as in Step S5 of the first embodiment in order to obtain the direction of the application region of the presaturation pulse. Is calculated (see FIG. 7).

  The calculation of the straight line 130 that linearly approximates the ventral spine boundary line 124 may be performed on the image data of all the images with different time phases, but the image data of any time phase image may be calculated. You may go only. This is because the abdominal body movement artifact caused by breathing is considered not to move much.

  [Step S6a] The imaging condition setting unit 84 corresponds to the thickness of the application region of the presaturation pulse by repeatedly performing the same processing as step S6 of the first embodiment on the image data of each time phase. The intervals of the straight lines 136 and 138 to be calculated are calculated (see FIG. 9).

  Next, the imaging condition setting unit 84 selects time-phase image data in which the distance between the straight line 136 and the straight line 138 (the thickness of the presaturation pulse region) is maximum (in FIG. 9, the time phase at time t1).

  Next, the imaging condition setting unit 84 tentatively determines an area between the straight lines 136 and 138 calculated for the selected image data as an application area of the presaturation pulse, and uses the application area as an imaging condition. The data is stored in the storage unit 82.

  The application region of the presaturation pulse automatically calculated in this way is displayed on the display device 64 by the display control unit 88 (for example, like the left image in FIG. 9).

  Here, the operator can change (adjust) the direction and width of the application region of the displayed presaturation pulse via the input device 62 as necessary. When there is no input from the operator regarding the application region of the presaturation pulse, the imaging condition setting unit 84 uses the application region automatically calculated as described above (provisionally determined) as the application region of the presaturation pulse. To decide.

  In addition, the automatically calculated application area may be automatically determined as the final application area without displaying the application area of the presaturation pulse automatically calculated as described above for confirmation by the operator.

  [Step S7a] In accordance with the imaging conditions finally determined as described above, imaging is performed in the same manner as in step S7 of the first embodiment.

  The above is the description of the operation of the second embodiment. In the second embodiment, the same effect as that of the first embodiment can be obtained.

  Furthermore, in the second embodiment, straight lines 136 and 138 corresponding to the presaturation pulse application region ends are calculated for each time-phase image data obtained by dynamic imaging. Then, a region between the straight lines 136 and 138 in the time-phase image data in which the interval between the straight lines 136 and 138 is maximum is tentatively determined and displayed as a presaturation pulse application region. Accordingly, the application region of the presaturation pulse is automatically calculated based on the image data of the time phase in which the abdomen swells most (that is, the inspiration phase), so that it is possible to reliably suppress the abdominal body motion artifacts due to breathing. .

<Third Embodiment>
FIG. 11 is a block diagram showing the overall configuration of the MRI apparatus 20A in the third embodiment. The difference from the first embodiment is that a breath synchronization unit 150 is further provided.

  The respiratory synchronization unit 150 includes a respiratory sensor (electrode) that is in contact with the chest of the subject P and detects a signal proportional to the rib cage motion. The respiration synchronization unit 150 calculates a respiration curve data from the detection signal of the respiration sensor, thereby generating a respiration synchronization signal synchronized with a desired period (for example, exhalation period) of the subject P, and this respiration synchronization. A signal is input to the sequence controller 50.

  Instead of the respiration synchronization unit 150, a configuration may be adopted in which a respiration cycle is detected by applying a frequency encoding gradient magnetic field pulse for collecting projection data for obtaining the respiration position of the subject P.

  Specifically, a plurality of time-series projection data is Fourier-transformed in the readout direction, respectively, thereby creating a plurality of projection data in real space indicating respiratory motion. Then, by referring to the projection data, the amount of movement of the imaging part such as the heart of the subject P due to respiration at the timing when each projection data is collected is obtained as a relative movement amount of the imaging part with respect to a certain reference position. Can do.

  As a method of obtaining the relative movement amount of the imaging part with respect to the reference position, for example, by taking a cross-correlation between the projection data corresponding to the reference position and the projection data for which the relative movement amount is to be obtained. And a method of obtaining a relative position shift amount.

  Alternatively, another configuration such as detecting the respiratory cycle by detecting the motion of the abdominal muscles as an optical variable may be used.

  Alternatively, the respiratory cycle may be detected using an RMC (real-time motion correction) method in place of the respiratory synchronization unit 150. RMC is a technique for correcting in real time the body movement of a subject that causes artifacts.

  In RMC, for example, MPP (motion probing pulse) is collected with ECG (electrocardiogram) synchronization. Then, the collection area of the imaging data and the collected data are corrected in real time so that the influence of movement due to respiration is removed using the amount of movement measured based on the MPP.

  The MPP is acquired from a region including the diaphragm, for example, with a phase encoding amount smaller than the phase encoding amount of the imaging data or without applying a phase encoding gradient magnetic field.

  Then, the position of the diaphragm in the body axis direction at the MPP collection time can be detected as a respiration level from the signal obtained by one-dimensional Fourier transform of the MPP. That is, when inhaling, the diaphragm falls to the foot side in the body axis direction, and when exhaling, the diaphragm rises to the head side in the body axis direction, so that the inspiration phase and the exhalation phase can be detected. Therefore, imaging at a timing corresponding to a desired respiratory phase is possible.

  Then, the amount of change from the reference value of the breathing level can be obtained as the amount of movement due to breathing. Further, the data collection area is moved by an amount corresponding to the amount of movement due to respiration. Thereby, the influence of the movement by respiration can be reduced.

The flow of the operation of the MRI apparatus 20A in the third embodiment is the same as that of the first embodiment described with reference to FIG. 8, and there are the following three differences from the first embodiment.
First, in step S1, respiratory synchronization is also designated as the imaging condition.

  Second, a respiratory synchronization signal is input from the respiratory synchronization unit 150 to the sequence controller 50 before the positioning image is captured in step S2. The MPU 80 acquires a respiratory synchronization signal from the sequence controller 50, and an inhalation phase positioning image is captured based on the respiratory synchronization signal.

  Third, in step S3, the boundary lines of the spine and the body surface are extracted based on the image data of the inspiration phase positioning image, and in steps S5 and S6, the presaturation pulse is based on the image data of the inspiration phase positioning image. Is automatically calculated and determined.

  As described above, also in the third embodiment, the same effect as in the first and second embodiments can be obtained. Furthermore, since the respiratory synchronization signal is used in the third embodiment, it is not necessary to perform a plurality of imaging at different time phases in order to acquire image data at the inspiration phase. Therefore, in order to reliably suppress abdominal body movement artifacts due to respiration, the presaturation pulse application area is determined based on the inspiration phase image data, and the number of positioning image slices used for the determination is minimized. Can do.

<Fourth Embodiment>
In the fourth embodiment, the application region of two prepulses, an IR pulse and a presaturation pulse, is automatically calculated by taking an example of imaging of the renal artery. Since the fourth embodiment is similar to the MRI apparatus 20 of the first embodiment shown in FIGS. 1 and 2 as the apparatus configuration, the configuration diagram is omitted, and the agreement of the MRI apparatus is the same as that of the first embodiment. Also assume 20.

  FIG. 12 is a schematic diagram showing a calculation method of the application region of the IR pulse and the presaturation pulse arranged in time series in the order of (1) to (4). In each figure, the left side shows a Coronal cross-sectional image. The right side shows Axial cross-sectional images. Specifically, FIG. 12 (1) shows after extraction of the kidney region, FIG. 12 (2) shows after imaging positioning, FIG. 12 (3) shows after calculation of the IR pulse application region 220, 12 (4) shows the pre-saturation pulse application region 224 after calculation. 12 (1) to 12 (4), the body surface boundary line 200 is a bold line, the kidney region 204 is a diagonal line, the renal artery 208 is a solid line, the vein 212 is a dotted line, and the imaging region 216 (which is a region of interest) is The IR pulse application region 220 is indicated by a dashed-dotted square frame, and the presaturation pulse application region 224 is indicated by a two-dot-dotted square frame.

  FIG. 13 is a flowchart showing the operation of the MRI apparatus 20 of the fourth embodiment. Hereinafter, the operation of the MRI apparatus 20 will be described according to the flowchart shown in FIG. 13 with reference to FIG.

  [Step S11] The imaging purpose is designated as “renal artery” by the operator via the input device 62. The imaging condition setting unit 84 stores “renal artery” in the condition storage unit 82 as an imaging condition, and acquires the imaging condition used when imaging the “renal artery” in the past from the condition storage unit 82. Is input to the display control unit 88.

  The display control unit 88 causes the display device 64 to display an example of imaging conditions used for imaging the “renal artery”. The operator can edit the imaging conditions by referring to the display contents. However, when there is no input, the imaging condition setting unit 84 sets so as to capture the Coronal sectional image and the Axial sectional image as the positioning images.

  [Step S12] When the operator gives an instruction to start imaging via the input device 62, the MRI apparatus 20 captures a positioning image, and the image reconstruction unit 90 generates image data of the positioning image. Is input to the image processing unit 92.

  The image processing unit 92 performs predetermined image processing on the input image data in accordance with the image processing conditions stored in the condition storage unit 82, and temporarily stores the image data after the image processing in the storage device 66.

  [Step S13] The image processing unit 92 acquires the image data of the positioning image from the storage device 66, and extracts the positions of the boundary lines of the kidney and the body surface based on the image data (see FIG. 12 (1)). .

For the extraction of the kidney region, for example, based on the statistical information of the human body model including the shape and size of each organ such as the kidney and lung, the relative positional relationship between the organs, Conventional image processing such as extracting matching organ regions may be used. The image processing unit 92 stores the extracted boundary line information of the kidney and body surface and inputs the information to the imaging condition setting unit 84.
[Step S14] The imaging condition setting unit 84 positions the imaging area 216 of the main scan.

  Specifically, the imaging region 216 in the axial section of the renal artery 208 is positioned so that the FOV is orthogonal to the positioning image in the coronal section (see the right side of FIG. 12 (2)).

  For the imaging region 216 in the Coronal section, the FOV is set by adding a margin set as an image processing condition so as to include the kidney region 204 extracted from the Coronal section image (in FIG. 12B). See left side).

  Further, the phase encoding direction of the axial sectional image of the renal artery is set to the front-rear direction of the subject P (the direction from the back to the abdomen).

  The above-described imaging condition setting result is stored in the condition storage unit 82 and displayed on the display device 64 by the display control unit 88. Note that the operator may manually adjust the imaging condition setting via the input device 62 as necessary.

  [Step S15] In this step S15, the IR pulse application region 220 is automatically calculated, and in the next step S16, the presaturation pulse application region 224 is automatically calculated. Here, since it is imaging of the renal artery 208, in the Coronal cross-sectional image on the left side of FIG. 12 (2), by suppressing the MR signal of blood flowing into the imaging region 216 from the lower side (both feet side) by the vein 212, It is desirable to effectively depict blood flowing through the renal artery 208 in the imaging region 216.

  For this purpose, first, by applying an IR pulse from the entire imaging region 216 to the lower side thereof, the nuclear spin of blood flowing through the renal artery 208 in the imaging region 216 also flows into the imaging region 216 from the lower side by the vein 212. The nuclear spin of blood that inverts the longitudinal magnetization component by 180 °.

  A presaturation pulse is applied from the lower end of the imaging region 216 to the lower side (inclining the longitudinal magnetization component of the nuclear spin by 90 °) at a timing different from that of the IR pulse. With this pre-saturation pulse, the blood flowing into the imaging region 216 from the lower side by the vein 212 is saturated with nuclear spin (longitudinal magnetization component is close to zero), and its MR signal is selectively suppressed. As a result, blood flowing through the renal artery 208 in the imaging region 216 can be selectively depicted.

  Therefore, in step S15, the imaging condition setting unit 84 sets the thickness direction of the IR pulse application region 220 in the axial direction (on the left side of FIG. 12 (3)) in accordance with the orientation of the imaging region 216 determined in step S14. In the Coronal cross-sectional image, it is set in the vertical direction of the drawing.

  Further, the imaging condition setting unit 84 matches the upper end of the IR pulse application region 220 in the Coronal section with the upper end of the imaging region 216 and sets the thickness of the IR pulse application region 220 to, for example, twice the imaging region 216. (Refer to the left side of FIG. 12 (3)).

  Here, the reason for “twice” is that a sufficient width to suppress the MR signal of the blood flow flowing into the imaging region 216 from the lower side by the vein 212 is about 2 of the thickness of the imaging region 216 empirically. This means that it is more than twice, and this embodiment is not particularly limited to this value.

  The thickness of the IR pulse application region 220 can be appropriately set in the imaging condition setting unit 84 in terms of how much the MR signal of the blood flow flowing into the imaging region 216 from the lower side by the vein 212 is to be suppressed. Good.

  In addition, the imaging condition setting unit 84 calculates the IR pulse application region 220 so that the region of interest is included in the axial section. Here, as an example, the imaging condition setting unit 84 sets the IR pulse application region 220 in the Axial section so as to match the imaging region 216 (in the Axial sectional image on the right side of FIG. The IR pulse application area 220 indicated by the alternate long and short dash line is drawn slightly shifted inside the imaging area 216 indicated by the solid line frame so as not to overlap.

  The imaging condition setting unit 84 causes the condition storage unit 82 to store the IR pulse application region 220 calculated as described above as an imaging condition. The IR pulse application region 220 tentatively determined in this way is displayed on the display device 64 by the display control unit 88 as shown in FIG.

  Here, the operator can change (adjust) the displayed IR pulse application region 220 via the input device 62 as necessary. When there is no input from the operator regarding the application region of the IR pulse application region 220, the imaging condition setting unit 84 designates the application region automatically calculated as described above (provisionally determined) as the IR pulse application region. Finally, 220 is determined as the application region.

  Note that the automatically calculated application area may be automatically determined as the final application area without displaying the application area of the IR pulse application area 220 automatically calculated as described above for operator confirmation. Good.

  [Step S16] The imaging condition setting unit 84 sets the thickness direction of the presaturation pulse application region 224 to be the same as the thickness direction of the IR pulse application region 220.

  The imaging condition setting unit 84 sets the thickness of the presaturation pulse application area 224 as follows. That is, in the Coronal section, the upper end of the presaturation pulse application region 224 matches the lower end of the imaging region 216, and the lower end of the presaturation pulse application region 224 matches the lower end of the IR pulse application region 220. Set (refer to the Coronal cross-sectional image on the left side of FIG. 12 (4)).

  That is, in the present embodiment, as an example, in the Coronal cross section, a region obtained by combining the imaging region 216 and the presaturation pulse application region 224 adjacent to each other is an IR pulse application region 220.

  In addition, the imaging condition setting unit 84 provisionally determines the presaturation pulse application region 224 so that the region of interest is included in the Axial cross section. Here, as an example, the imaging condition setting unit 84 sets the presaturation pulse application region 224 in the Axial cross section to match the imaging region 216 (in the Axial cross-sectional image on the right side of FIG. The pre-saturation pulse application area 224 indicated by the two-dot chain line is drawn slightly shifted inside the imaging area 216 indicated by the solid line frame so that the two do not overlap.

  The imaging condition setting unit 84 causes the condition storage unit 82 to store the presaturation pulse application region 224 set as described above as an imaging condition. The presaturation pulse application region 224 automatically calculated (provisionally determined) in this way is displayed on the display device 64 by the display control unit 88 as shown in FIG.

  Here, the operator can change (adjust) the displayed presaturation pulse application region 224 via the input device 62 as necessary. When there is no input from the operator regarding the application region 224 of the presaturation pulse, the imaging condition setting unit 84 uses the application region automatically calculated (tentatively determined) as described above as the application region 224 of the presaturation pulse. As the final decision.

  The automatically calculated application region is automatically determined as the final application region without displaying the application region of the presaturation pulse application region 224 automatically calculated as described above for operator confirmation. Also good.

  [Step S17] Imaging is performed according to the imaging conditions determined as described above. That is, the IR pulse and the presaturation pulse are applied at different timings to each region (220, 224) determined as described above. Thereafter, an RF pulse or the like for data collection is applied.

As a result, image data of the MR image of the imaging region 216 targeting the renal artery 208 is generated and stored in the storage device 66. The image data is displayed as an image on the display device 64 by the display control unit 88.
The above is the description of the operation of the MRI apparatus 20C of the fourth embodiment.

  As described above, in the fourth embodiment, in addition to the presaturation pulse application region 224, the IR pulse application region 220 is also automatically calculated by the MRI apparatus 20. Therefore, the burden of setting the imaging conditions by the operator is greatly reduced. As a result, the throughput of inspection using the MRI apparatus 20 can be greatly improved.

  According to the embodiments described in detail above, it is possible to make it easier to set the imaging condition related to the pre-pulse in MRI than in the past.

<Supplementary items of the embodiment>
[1] In the first to fourth embodiments, the example in which the positioning image is used in the process of automatically calculating the application region of the presaturation pulse and the IR pulse has been described. The embodiment of the present invention is not limited to such an aspect. MR images obtained in other imaging sequences performed before calculation and determination of the application region of the presaturation pulse or IR pulse may be used for determination of the application region.

  [2] An example in which the method for automatically determining a pre-pulse application region according to the present invention is applied to imaging of a spinal region and a renal artery has been described. The embodiment of the present invention is not limited to such an aspect. The embodiment of the present invention can also be applied when imaging other regions such as the heart.

  For example, a case where the heart is imaged will be described. The heart contracts in the time phase for sending out blood, and expands in the time phase for blood flow into the ventricle. Accordingly, an ECG unit that acquires an ECG (electrocardiogram) signal representing heartbeat information of the subject P is provided, the time phase in which the heart is most expanded is detected, the heart region is extracted based on the image data of the time phase, and the heart In addition, the application region of the prepulse may be automatically determined so as to suppress the flow artifact of the large blood vessel.

  Alternatively, depending on the purpose of imaging, a heart region may be extracted based on image data at a time phase when the heart contracts most, and a pre-pulse application region may be automatically determined.

  [3] The present invention is also applicable to, for example, automatic determination of the application area of a region selection IR pulse or a region non-selection IR pulse in a t-SLIP (Time Spatial Labeling Inversion Pulse) method.

  Here, the t-SLIP method is one of imaging methods for performing blood labeling, and uses a plurality of labeling pulses. In the pulse sequence of the t-SLIP method, labeling is performed by applying an ASL pulse (Arterial Spin Labeling Pulse) to blood flowing into the imaging region.

  After that, if MR signal data is collected after an inversion time (TI), labeled blood that has reached the imaging region can be selectively depicted.

  Note that the pulse sequence of the t-SLIP method includes at least a region selection IR pulse, and the region non-selection IR pulse can be switched on and off. That is, the pulse sequence of the t-SLIP method may be composed of only region selection IR pulses or may be composed of both region selection IR pulses and region non-selection IR pulses.

  [4] In the second and third embodiments, the example in which the application region of the presaturation pulse is determined based on the image data obtained by the imaging at the intake phase has been described. The embodiment of the present invention is not limited to such an aspect. Depending on the location of the region of interest and the imaging purpose, the application region of the presaturation pulse may be determined based on image data obtained by imaging during the exhalation phase.

  [5] A correspondence relationship between the terms of the claims and the embodiments will be described. In addition, the correspondence shown below is one interpretation shown for reference, and does not limit the present invention.

  An image processing unit 92 (see FIG. 2) that extracts a ventral body surface boundary line 120, a ventral spine boundary line 124, and the like, and an application region of a presaturation pulse or an IR pulse based on the extraction result of the image processing unit 92 are automatically performed. The imaging condition setting unit 84 that calculates and determines automatically is an example of a calculation unit described in claims.

  The ventral body surface boundary line 120 is an example of a tissue region. The term “tissue region” means, for example, a general term for regions of human tissues such as the body surface (body surface), bones, blood vessels, and organs.

  The functions of the display control unit 88 and the display device 64 that display the presaturation pulse application region and the IR pulse application region automatically calculated by the imaging condition setting unit 84 are examples of the display unit.

  [6] Although several embodiments of the present invention 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, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

20, 20A MRI apparatus 22 Magnet for static magnetic field 24 Shim coil 26 Gradient magnetic field coil 28 RF coil 30 Control system 32 Bed 40 Static magnetic field power supply 42 Shim coil power supply 44 Gradient magnetic field power supply 46 RF transmitter 48 RF receiver 50 Sequence controller 52 Computer 60 Arithmetic Device 62 Input device 64 Display device 66 Storage device 80 MPU
82 Condition storage unit 84 Imaging condition setting unit 86 Image processing condition setting unit 88 Display control unit 90 Image reconstruction unit 92 Image processing unit 94 System bus 100, 102 Outer edge 104 of imaging slice Body surface boundary line 106 Body tissue contour 108 Spine Outline 116 positioning image outer edge 120 ventral body surface boundary line 122 dorsal body surface boundary line 124 ventral spine boundary line 126 dorsal spine boundary line 128 imaging slice outer edge 150 respiration synchronization unit 200 body surface boundary line 204 kidney region 208 renal artery 212 vein 216 imaging region 220 IR pulse application region 224 presaturation pulse application region

Claims (6)

A first imaging unit that executes a first imaging sequence;
A first image generation unit that generates first image data using a nuclear magnetic resonance signal obtained by executing the first imaging sequence;
A calculation unit that calculates an application region of a pre-pulse applied in a second imaging sequence different from the first imaging sequence based on the first image data;
A second imaging unit that executes the second imaging sequence with the application of the pre-pulse;
A second image generation unit that generates second image data using a nuclear magnetic resonance signal obtained by execution of the second imaging sequence;
The calculating unit linearly approximates a ventral spine boundary line and the ventral spine boundary line from a spine region that is a region of a specific tissue in the body of the subject extracted from the first image data. A second straight line parallel to the first straight line and circumscribing from the ventral side to the ventral spinal boundary, and using the second straight line, the prepulse application region To calculate,
Magnetic resonance imaging device. The magnetic resonance imaging apparatus according to claim 1.
The magnetic resonance imaging apparatus, wherein the first imaging sequence collects positioning images of images collected in the second imaging sequence, which is performed prior to the second imaging sequence. The magnetic resonance imaging apparatus according to claim 1.
The first image data is image data obtained by intervertebral disc imaging,
Magnetic resonance imaging device. The magnetic resonance imaging apparatus according to claim 1.
The first imaging unit executes a first imaging sequence that is dynamic imaging,
The first image generation unit generates first image data for a plurality of time phases,
The calculation unit extracts a ventral body surface boundary line from the first image data for the plurality of time phases , is parallel to the second straight line, and is abdominal to the ventral body surface boundary line. A third straight line circumscribing from the outside is obtained, and a fourth straight line and a fifth straight line obtained by translating the second straight line and the third straight line to the ventral side by a predetermined margin are obtained. The prepulse application candidate regions corresponding to the plurality of time phases are respectively obtained using the fourth straight line and the fifth straight line, and the fourth candidate out of the plurality of time phase application candidate regions . A magnetic resonance imaging apparatus that calculates an area where the thickness of the subject in the dorsoventral direction , which is an interval between a straight line and a fifth straight line, is maximum as an application area of the prepulse. The magnetic resonance imaging apparatus according to claim 1.
The first imaging unit executes the first imaging sequence with respiratory synchronization,
The first image generation unit generates the first image data corresponding to a predetermined respiratory phase,
The said calculating part is a magnetic resonance imaging apparatus which calculates the application area | region of the said prepulse based on 1st image data corresponding to the said predetermined respiration phase. The magnetic resonance imaging apparatus according to any one of claims 1 to 5,
A magnetic resonance imaging apparatus further comprising: a display unit that displays an application region of the prepulse calculated by the calculation unit before the execution of the second imaging sequence.

Images