JP2014050530A - Magnetic resonance imaging apparatus and magnetic resonance imaging method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic resonance imaging apparatus capable of easily acquiring a desired sectional image, and a magnetic resonance imaging method.SOLUTION: The magnetic resonance imaging apparatus according to one embodiment includes a determination unit 26c, a change unit, an imaging unit, and a generation unit. The determination unit 26c determines whether or not an imaging range including a desired sectional image is within a limit range of imaging. As a result of the determination, when it is determined to exceed the limit range, the change unit changes the setup of the imaging range to that within a limit range. The imaging unit executes imaging on the basis of the setup after the change. The generation unit generates the desired sectional image from the data obtained by the imaging.

Description

  Embodiments described herein relate generally to a magnetic resonance imaging apparatus and a magnetic resonance imaging method.

  In magnetic resonance imaging, a positioning image for positioning an imaging range of a cross-sectional image used for diagnosis or the like is collected in advance in a low resolution and in a short time, and an imaging range of the cross-sectional image is set for this positioning image. . There are a manual method and an automatic method for setting the imaging range. In the case of the manual method, for example, the operator manually sets the imaging range for the positioning image displayed on the display unit. On the other hand, in the case of an automatic method, processing using anatomical feature points is performed on three-dimensional data collected as a positioning image, and an imaging range is automatically set. In the latter case, the labor of the operator is saved and the setting variation among the operators can be suppressed.

  Incidentally, EPI (Echo Planar Imaging) imaging is one of imaging methods for magnetic resonance imaging. EPI imaging is a high-speed imaging method that collects data in the entire k-space with a single excitation. In EPI imaging, in order to shorten the echo interval and reduce the influence of magnetic field inhomogeneity, it is necessary to raise the readout gradient magnetic field at high speed, and the amount of change in the gradient magnetic field per unit time is also large. For this reason, in the case of double oblique where the read lead axis extends over 2 ch or more of X, Y, and Z, the oblique angle that can be imaged is limited by the limitation of the magnetic stimulation by dB / dt. For example, when the subject lies on his / her back on the bed, the magnetic stimulation is likely to be affected in the Y-axis direction (direction perpendicular to the bed surface) of the apparatus coordinate system.

  Here, when the imaging range is automatically set, based on the anatomical information of the subject, for example, a median cross-sectional image or a cross-sectional image orthogonal to the median cross-sectional image is automatically set as the imaging range. There are many cases. In this case, even if a T1-weighted image, a T2-weighted image, a FLAIR (fluid-attenuated inversion recovery) image or the like can be captured, a diffusion-weighted (Diffusion) image by EPI imaging or a perfusion image by EPI imaging is captured. There are cases where it is not possible. In clinical examination, an image obtained by EPI imaging of the same cross section as a T1-weighted image, a T2-weighted image, or the like may be required. In such a case, there is a possibility that troubles such as resetting the subject again may occur so that EPI imaging can be performed.

JP 2010-88872 A

  The problem to be solved by the present invention is to provide a magnetic resonance imaging apparatus and a magnetic resonance imaging method capable of easily obtaining a desired cross-sectional image.

  The magnetic resonance imaging apparatus according to the embodiment includes a determination unit, a change unit, an imaging unit, and a generation unit. The determination unit determines whether an imaging range including a desired cross-sectional image is within an imaging limit range. If it is determined as a result of the determination that the range exceeds the limit range, the change unit changes the setting of the imaging range within the limit range. The imaging unit performs imaging based on the changed setting. The generation unit generates the desired cross-sectional image from data obtained by the imaging.

FIG. 1 is a diagram illustrating a configuration of an MRI (Magnetic Resonance Imaging) apparatus according to the present embodiment. FIG. 2 is a flowchart showing a processing procedure in the present embodiment. FIG. 3 is a diagram for explaining feature points in the present embodiment. FIG. 4 is a diagram showing an imaging range automatically set in the present embodiment. FIG. 5 is a diagram for explaining a limit range of an oblique angle in the present embodiment. FIG. 6 is a diagram for explaining the changed imaging range in the present embodiment. FIG. 7 is a view for explaining generation of a cross-sectional image in the present embodiment. FIG. 8 is a flowchart showing a processing procedure by the imaging range changing unit according to the present embodiment. FIG. 9 is a flowchart illustrating a processing procedure performed by the imaging range changing unit according to the present embodiment.

  Hereinafter, a magnetic resonance imaging apparatus (hereinafter referred to as “MRI apparatus” as appropriate) and a magnetic resonance imaging method according to an embodiment will be described with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of an MRI apparatus 100 according to the present embodiment. The subject P is not included in the MRI apparatus 100. The static magnetic field magnet 1 is formed in a hollow cylindrical shape and generates a uniform static magnetic field in an internal space. The static magnetic field magnet 1 is, for example, a permanent magnet or a superconducting magnet. The gradient coil 2 is formed in a hollow cylindrical shape and generates a gradient magnetic field in the internal space. Specifically, the gradient magnetic field coil 2 is disposed inside the static magnetic field magnet 1 and receives a power supply from the gradient magnetic field amplifier 3 to generate a gradient magnetic field. The gradient magnetic field amplifier 3 supplies electric power to the gradient magnetic field coil 2 in accordance with a control signal transmitted from the sequence control unit 10.

  The bed 4 includes a top plate 4a on which the subject P is placed, and the top plate 4a is inserted into the cavity of the gradient magnetic field coil 2 serving as an imaging port in a state where the subject P is placed. Usually, the bed 4 is installed such that the longitudinal direction is parallel to the central axis of the static magnetic field magnet 1. The couch controller 5 drives the couch 4 to move the couchtop 4a in the longitudinal direction and the vertical direction.

  The transmission coil 6 generates a high frequency magnetic field. Specifically, the transmission coil 6 is disposed inside the gradient magnetic field coil 2 and receives a supply of an RF (Radio Frequency) pulse from the transmission unit 7 to generate a high-frequency magnetic field. The transmission unit 7 transmits an RF pulse corresponding to the Larmor frequency to the transmission coil 6 in accordance with the control signal transmitted from the sequence control unit 10.

  The receiving coil 8 receives a magnetic resonance signal (hereinafter referred to as “MR (Magnetic Resonance) signal” as appropriate). Specifically, the receiving coil 8 is disposed inside the gradient coil 2 and receives an MR signal radiated from the subject P due to the influence of the high-frequency magnetic field. The receiving coil 8 outputs the received MR signal to the receiving unit 9.

  The receiving unit 9 generates MR signal data based on the MR signal output from the receiving coil 8 in accordance with the control signal sent from the sequence control unit 10. Specifically, the receiving unit 9 generates MR signal data by digitally converting the MR signal output from the receiving coil 8, and sends the generated MR signal data to the computer system 20 via the sequence control unit 10. Send. The receiving unit 9 may be provided on the gantry device side including the static magnetic field magnet 1, the gradient magnetic field coil 2, and the like.

  The sequence control unit 10 controls the gradient magnetic field amplifier 3, the transmission unit 7, and the reception unit 9. Specifically, the sequence control unit 10 transmits a control signal based on the pulse sequence execution data transmitted from the computer system 20 to the gradient magnetic field amplifier 3, the transmission unit 7, and the reception unit 9.

  The computer system 20 includes an interface unit 21, an image reconstruction unit 22, a storage unit 23, an input unit 24, a display unit 25, and a control unit 26. The interface unit 21 is connected to the sequence control unit 10 and controls input / output of data transmitted / received between the sequence control unit 10 and the computer system 20. The image reconstruction unit 22 reconstructs image data from the MR signal data transmitted from the sequence control unit 10 and stores the reconstructed image data in the storage unit 23.

  The storage unit 23 stores parameter values set as parameters included in the imaging conditions, image data stored by the image reconstruction unit 22, and other data used in the MRI apparatus 100. For example, the storage unit 23 is a semiconductor memory element such as a RAM (Random Access Memory) or a flash memory, a hard disk, an optical disk, or the like.

  The input unit 24 receives various instructions for editing imaging conditions, imaging instructions, and the like from the operator. For example, the input unit 24 receives a parameter value setting instruction or the like for a parameter included in the imaging condition. For example, the input unit 24 is a mouse, a keyboard, or the like. The display unit 25 displays an imaging condition editing screen, an image, and the like.

  The control unit 26 comprehensively controls the MRI apparatus 100 by controlling each unit described above. For example, when the editing of the imaging condition is received from the operator, the control unit 26 generates pulse sequence execution data based on the received imaging condition, and transmits the generated pulse sequence execution data to the sequence control unit 10. For example, the control unit 26 is an integrated circuit such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA), or an electronic circuit such as a central processing unit (CPU) or a micro processing unit (MPU). As shown in FIG. 1, the control unit 26 according to the present embodiment includes a positioning image collection unit 26a, an imaging range setting unit 26b, a determination unit 26c, an imaging range change unit 26d, and an EPI imaging unit 26e. And a cross-sectional image generator 26f. The processing by each of these units will be described in detail later.

  FIG. 2 is a flowchart showing a processing procedure in the present embodiment. In the present embodiment, an example in which an EPI image of a cross-sectional image with a head is taken as a desired cross-sectional image will be described. Note that the “desired cross-sectional image” is an image used for diagnosis or the like, unlike the positioning image used for setting the imaging range.

  First, the positioning image collection unit 26a collects positioning images (step S01). For example, the positioning image collection unit 26a collects three-dimensional data as a positioning image.

  Next, the imaging range setting unit 26b sets an imaging range including a desired cross-sectional image for the positioning image collected in step S01 (step S02). Specifically, the imaging range setting unit 26b according to the present embodiment automatically sets the imaging range by an automatic positioning function. For example, the imaging range setting unit 26b detects the inclination of the head in three dimensions from the three-dimensional data collected in step S01, and a desired cross-sectional image (for example, an AC-PC slice cross-sectional image) in subsequent EPI imaging. The slice position is automatically rotated and moved so that an image can be captured. In the present embodiment, the imaging range is set in a range including a slice position (for example, a range having a certain slice thickness with the slice position as a central slice).

  As a typical technique for automatic positioning, first, a desired cross-sectional image and information on anatomically important feature points (landmarks) included in the cross-sectional image are registered in advance. The imaging range setting unit 26b identifies a central sagittal plane that divides the left and right brain hemispheres from the three-dimensional data collected as the positioning image, and generates a central sagittal cross-sectional image by reformatting. Subsequently, the imaging range setting unit 26b finds a position of a feature point registered in advance in the central sagittal cross-sectional image. FIG. 3 is a diagram for explaining the feature points in the present embodiment, and black circles correspond to the feature points. Then, the imaging range setting unit 26b evaluates the position of the feature point found from the central sagittal cross-sectional image, thereby setting the rotation amount and the movement amount for setting a slice position for obtaining a desired cross-sectional image registered in advance. Ask.

  FIG. 4 is a diagram illustrating an imaging range that is automatically set in the present embodiment. In FIG. 4, the positioning image is represented by two cross-sectional images, a sagittal cross-sectional image and a coronal cross-sectional image, and an imaging range ROI (Region Of Interest) a is set in a tilted state with respect to these cross-sectional images. Yes. As shown in FIG. 4, the imaging range is set in a range having a certain slice thickness so as to include a desired cross-sectional image.

  Although the method for automatically setting the imaging range has been described, the embodiment is not limited to this, and may be set manually. In this case, for example, as a positioning image, two cross-sectional images, a sagittal cross-sectional image and a coronal cross-sectional image, are collected, and an operator manually captures an imaging range for these cross-sectional images displayed as shown in FIG. ROIa may be set. Also in this case, three-dimensional data may be collected as a positioning image.

  Subsequently, the determination unit 26c determines whether or not the imaging range set in step S02 is within the EPI imaging limit range (step S03). Specifically, the determination unit 26c determines whether or not the imaging range set in step S02 is within the limit range of the EPI imaging oblique angle.

  FIG. 5 is a diagram for explaining the limit range of the oblique angle in the present embodiment. FIG. 5A shows a cross-sectional image represented by four vectors (Slice Offset Vector, Slice Orient Vector, Phase Orient Vector, and Read Orient Vector). FIG. 5B shows the XYZ components of each vector.

Assuming that the XYZ components of the Slice Orient Vector are (Sx, Sy, Sz) and the XYZ components of the Phase Orient Vector are (Px, Py, Pz), these components are the Tilt angle θ and the Slew angle φ. Can express.
(Sx, Sy, Sz) = (cosθsinφ, sinθ, cosθcosφ)
(Px, Py, Pz) = (cosφ, 0, -sinφ) or (-sinθsinφ, cosθ, -sinθcosφ)
The XYZ component of Read Orient Vector can be obtained from the outer product of both.

Since the oblique angle is limited in EPI imaging, the range of values of θ and φ is also limited for EPI imaging. In this embodiment, the limit range of the oblique angle in which EPI imaging is possible is as follows.
θ: 0 ± θlimit [deg] OR 90 ± θlimit [deg] OR 180 ± θlimit [deg] OR 270 ± θlimit [deg]
φ: 0 ± φlimit [deg] OR 90 ± φlimit [deg] OR 180 ± φlimit [deg] OR 270 ± φlimit [deg]

  When a plurality of cross-sectional images are included in the imaging range having a constant slice thickness, the determination unit 26c determines whether the entire imaging range or each cross-sectional image is within the limit range of the oblique angle. .

  As a result of the determination in step S03, if it is determined that the limit range is exceeded (No in step S03), the imaging range changing unit 26d changes the setting of the imaging range to be within the limited range (step S04). On the other hand, as a result of the determination in step S03, if it is determined that it is within the limited range (step S03, Yes), the processing by the imaging range changing unit 26d is not performed, and the process proceeds to step S05.

  FIG. 6 is a diagram for explaining the changed imaging range in the present embodiment. As can be seen from a comparison between FIG. 6 and FIG. 4, the changed imaging range ROIb is smaller in inclination than the imaging range ROIa of FIG. 4 with respect to the two cross-sectional images of the sagittal cross-sectional image and the coronal cross-sectional image. . Details of the setting change by the imaging range changing unit 26d will be described later.

  Next, the EPI imaging unit 26e executes EPI imaging based on the changed setting changed in step S04 (step S05), reconstructs the three-dimensional data obtained by EPI imaging, and displays an image. Is generated (step S06). The image generated in step S06 is an image that has not been subjected to distortion correction. Note that an image generated by reconstructing three-dimensional data obtained by EPI imaging is appropriately referred to as an “EPI image”.

  Subsequently, the cross-sectional image generation unit 26f generates a desired cross-sectional image from the EPI image generated in step S06 by MPR (Multi Planar Reconstruction) cross-sectional transformation (step S07). Then, the cross-sectional image generation unit 26f performs distortion correction on the desired cross-sectional image generated by MPR in step S07 (step S08). That is, the cross-sectional image generation unit 26f generates a desired cross-sectional image, and then performs distortion correction on the cross-sectional image to obtain a desired cross-sectional image that has been subjected to distortion correction.

  Here, the distortion correction is to correct an artifact on the image caused by the nonlinearity of the gradient magnetic field strength. For example, the distortion correction technique has in advance a position coordinate correction table for converting “an actual gradient magnetic field strength distribution having non-linearity” into a “virtual gradient magnetic field strength distribution having linearity”. The reconstructed image is corrected using the table. That is, information on how much distortion occurs (for example, “position coordinate correction table”) is known, and in the present embodiment, three-dimensional data is collected in step S05, and the distorted destination information is collected. Since the position coordinates of the data are also known, correction to an image without distortion can be executed by calculation.

  FIG. 7 is a diagram for explaining generation of a cross-sectional image in the present embodiment. As shown in FIG. 7A, in the present embodiment, the cross-sectional image generation unit 26f picks up a desired cross-sectional image by cross-sectional conversion from the generated EPI image captured in the changed imaging range. Is. However, in practice, the EPI image generated in step S06 is an image of a distorted cross section, as shown in FIG. In FIG. 7B, only the distortion in the slice direction is expressed, but the distortion in the cross section may occur in the same manner.

  If the desired cross-sectional image is taken out by cross-sectional conversion after performing distortion correction on this EPI image, the image data is changed by the distortion correction, and there is no cross-sectional image data to be obtained by cross-sectional conversion. Alternatively, the data is replaced with 0 data, and there is a possibility that a desired cross-sectional image cannot be obtained without correct cross-sectional conversion. For this reason, in this embodiment, first, after taking out a desired cross-sectional image from the EPI image without performing distortion correction, the distortion correction is performed on the extracted cross-sectional image.

  8 and 9 are flowcharts showing a processing procedure by the imaging range changing unit 26d according to the present embodiment. FIG. 8 shows a method for changing the setting of the imaging range based on the number of anatomical feature points included, and FIG. 9 shows a method for changing the setting of the imaging range based on the distance from the feature points. Show. As described above, the cross-sectional image is expressed by four vectors (Slice Offset Vector, Slice Orient Vector, Phase Orient Vector, and Read Orient Vector). 8 and 9, “offset vector” corresponds to Slice Offset Vector, and “slice vector” corresponds to Slice Orient Vector.

  The imaging range changing unit 26d changes the Tilt angle for the vector indicating the cross-sectional image by 1 degree within the limit range (step S101). In addition, the imaging range changing unit 26d changes the Slew angle for the vector indicating the cross-sectional image one by one within the limit range (step S102). Further, the imaging range changing unit 26d changes the offset vector from the magnetic field center of the cross-sectional image by 1 mm in the direction of the slice vector with respect to the automatically positioned offset vector (step S103).

  In this way, the imaging range changing unit 26d changes the four vectors indicating the cross-sectional image little by little within the limit range of the oblique angle. Each time, the imaging range changing unit 26d includes the feature points (landmarks) used in the automatic positioning of the imaging range in step S02 of FIG. 2 in the cross-sectional image planned for imaging in steps S101 to S103. The number is checked (step S104).

  Subsequently, the imaging range changing unit 26d determines whether or not the number checked in step S104 is the maximum among the numbers checked so far (step S105). In the maximum case (step S105, Yes), the imaging range changing unit 26d determines the maximum number at that time and the cross-sectional information (Tilt angle) of the cross-sectional image planned in steps S101 to S103 at this time. , Slew angle, offset vector) are recorded (step S106).

  Next, the imaging range changing unit 26d determines whether or not the amount of change in the slice vector direction has reached the slice thickness set as the imaging range (step S107), and if not (step S107, No), returning to the process of step S103 again, the offset vector is changed by 1 mm, and the process of steps S104 to S106 is performed for a new cross-sectional image.

  On the other hand, when the amount of change in the slice vector direction reaches the slice thickness set as the imaging range (step S107, Yes), the imaging range changing unit 26d takes all values within the limited range for the Slew angle. (Step S108), if all values are not taken (No at Step S108), the process returns to Step S102 again, the Slew angle is changed once, and a new cross-sectional image is obtained. Steps S103 to S107 are performed.

  On the other hand, when all the values have been taken (step S108, Yes), the imaging range changing unit 26d determines whether all values within the limit range have been taken for the tilt angle (step S109). When the value is not taken (No at Step S109), the processing returns to Step S101 again, the Tilt angle is changed once, and the processing of Steps S102 to S108 is performed for a new cross-sectional image.

  In this way, the imaging range changing unit 26d records the cross-section information that maximizes the number of feature points while gradually changing the four vectors indicating the cross-sectional image within the limit range of the oblique angle. Then, when the imaging range changing unit 26d takes all the values within the limited range for the Tilt angle (step S109, Yes), the cross-sectional information recorded in step S106 is used as the cross-sectional information indicating a desired cross-sectional image. (Step S110). That is, for example, the imaging range changing unit 26d sets an imaging range having a constant slice thickness as the imaging range after the change, with the slice position indicated by the cross-sectional information as the central slice.

  Note that the method of FIG. 9 differs from the method of FIG. 8 only in the processing of steps S204 to S206. That is, in the case of the method of FIG. 9, the imaging range changing unit 26d uses the feature points (landmarks) used in the automatic positioning of the imaging range in step S02 of FIG. 2 and the cross-sectional image planned for imaging in steps S201 to S203. The total sum of the distances is checked (step S204).

  Subsequently, the imaging range changing unit 26d determines whether or not the sum of the distances examined in step S204 is the smallest of the sums of distances examined so far (step S205). In the case of the minimum (step S205, Yes), the imaging range changing unit 26d displays the minimum value of the distance at that time and the cross-sectional information (Tilt) of the cross-sectional image planned for imaging in steps S201 to S203 at this time. Corner, Slew angle, offset vector) are recorded (step S206).

  As described above, according to the present embodiment, it is possible to obtain a desired cross-sectional image from the EPI image collected in the changed imaging range after changing the imaging range of EPI imaging to an appropriate imaging range. A desired cross-sectional image can be easily obtained. Even when the imaging range is set by automatic positioning and becomes double oblique, it is not necessary to set the subject again, so the labor required for the examination can be reduced.

(Other embodiments)
Note that the embodiment is not limited to the above-described embodiment.

  For example, in the above-described embodiment, an example in which a cross-sectional image of the head is captured by EPI imaging as a desired cross-sectional image for diagnosis has been described, but the embodiment is not limited thereto. Even in the case of a part other than the head or in the case of performing imaging other than EPI imaging, for example, if there is a limited range in the imaging range, similarly Can be applied.

  Moreover, although the example of FIG.8 and FIG.9 was shown as a concrete method of the change of the setting of an imaging range, Embodiment is not restricted to this. For example, an imaging range that is within the limited range and is closest to the imaging range set in step S02 of FIG. 2 (the change in the Tilt angle or Slew angle is small) is set as the changed imaging range. Also good. In addition, when the imaging range before the change and the imaging range after the change are compared, the sizes do not necessarily have to be completely the same. For example, in view of taking out a desired cross-sectional image later by cross-sectional conversion, the slice thickness after change may be changed as appropriate, for example, by increasing the slice thickness after change.

  According to the magnetic resonance imaging apparatus and magnetic resonance imaging method of at least one embodiment described above, a desired cross-sectional image can be easily obtained.

  Although several embodiments of the present invention 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, 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.

DESCRIPTION OF SYMBOLS 100 MRI apparatus 26 Control part 26a Positioning image collection part 26b Imaging range setting part 26c Judgment part 26d Imaging range change part 26e EPI imaging part 26f Cross-section image generation part

Claims (6)

A determination unit that determines whether or not an imaging range including a desired cross-sectional image is within a limited range of imaging;
As a result of the determination, if it is determined that the limit range is exceeded, a change unit that changes the setting of the imaging range to within the limit range;
An imaging unit that performs imaging based on the changed setting;
A magnetic resonance imaging apparatus comprising: a generation unit that generates the desired cross-sectional image from data obtained by the imaging. The determination unit determines whether the imaging range is within a limit range of oblique angles,
When it is determined that the change unit exceeds the limit range, the changing unit changes the setting of the imaging range so that the oblique angle is within the limit range,
The magnetic resonance imaging apparatus according to claim 1, wherein the generation unit generates the desired cross-sectional image from three-dimensional data obtained by the imaging.   The generation unit generates the desired cross-sectional image from the uncorrected data obtained by the imaging, and then performs distortion correction on the cross-sectional image to obtain the desired distortion-corrected desired image. The magnetic resonance imaging apparatus according to claim 1, wherein a cross-sectional image is obtained. A collection unit for collecting a positioning image used for positioning of an imaging range including the desired cross-sectional image;
A setting unit that automatically sets an imaging range including the desired cross-sectional image using anatomical feature points with respect to the positioning image;
The said change part changes the setting of the said imaging range in a restriction | limiting range based on the number with the said feature point, or the distance with the said feature point, The change to any one of Claims 1-3 characterized by the above-mentioned. The magnetic resonance imaging apparatus described. A collection unit for collecting a positioning image used for positioning of an imaging range including a desired cross-sectional image;
A setting unit for setting an imaging range including the desired cross-sectional image for the positioning image;
A changing unit for changing the oblique angle of the setting of the imaging range;
An imaging unit that performs imaging based on the changed setting;
A magnetic resonance imaging apparatus comprising: a generation unit configured to generate the desired cross-sectional image from three-dimensional data obtained by the imaging. A magnetic resonance imaging method executed in a magnetic resonance imaging apparatus,
A collection step of collecting a positioning image used for positioning of an imaging range including a desired cross-sectional image;
A setting step for setting an imaging range including the desired cross-sectional image for the positioning image;
A determination step of determining whether the set imaging range is within a limit range of an oblique angle of EPI (Echo Planar Imaging) imaging;
As a result of the determination, if it is determined that the limit range is exceeded, a change step of changing the setting of the imaging range so that the oblique angle is within the limit range;
An EPI imaging process for performing EPI imaging based on the changed settings;
A generating step of generating the desired cross-sectional image from the three-dimensional data obtained by EPI imaging by MPR (Multi Planar Reconstruction);
And a distortion correction step of performing distortion correction on a desired cross-sectional image generated by MPR.

Images