JP5127305B2 - Magnetic resonance imaging system - Google Patents

Description

  The present invention relates to a magnetic resonance imaging apparatus that performs imaging for determining a slice region for a required part of a subject, sets the slice region of the required part, and performs imaging.

  In recent years, image data generated by an image diagnostic apparatus such as an X-ray CT (computed tomography) apparatus, an MRI (magnetic resonance imaging) apparatus, and an ultrasonic diagnostic apparatus is converted into an image such as an MPR (multi-planar structure) image or a three-dimensional image. Data is being processed and displayed.

The MPR image includes an axial image, a coronal image, a sagittal image, an oblique image, a double oblique image, a curved surface MPR image, and the like as three orthogonal cross sections. When imaging is performed by selecting three orthogonal sections, an MPR image as a two-dimensional captured image generated based on the three orthogonal sections is used as a positioning image. At the time of positioning, the width (slice region) in the orthogonal direction of the cross section of the MPR image was determined based on the slice conditions (slice thickness, number of slices, and slice length) (see, for example, Patent Document 1).
JP 2003-290171 A

  In the conventional technique, the operator cannot visually determine the slice area.

  The present invention has been made in consideration of the above-described circumstances, and an object thereof is to provide a magnetic resonance imaging apparatus capable of improving the operability of an operator when setting a slice region.

  In order to solve the above-described problems, a magnetic resonance imaging apparatus according to the present invention performs imaging for positioning a required part of a subject and generates an original image that is a cross-sectional image. And an orthogonal image generation unit that generates two orthogonal images, which are two cross-sectional images orthogonal to the original image, based on the original image generated by the original image generation unit, and the original image generation unit A first MPR cross section that is orthogonal to a cross section of at least one cross-sectional image among three cross-sectional images of the original image generated by the orthogonal image generation unit and the two orthogonal images generated by the orthogonal image generation unit is set. A 1 MPR section setting unit; a first MPR image generation unit that generates a first MPR image in the first MPR section set by the first MPR section setting unit; and the first M Two cross sections each including two parallel straight lines set on the first MPR cross section set by the R cross section setting section and orthogonal to the first MPR cross section are set as two second MPR cross sections. A second MPR cross-section setting unit, a second MPR image generation unit that generates two second MPR images in the two second MPR cross-sections set by the second MPR cross-section setting unit, and the second MPR image generation An image display control unit for controlling display of the two second MPR images generated by the unit, and the second MPR section set on the two second MPR sections set by the second MPR section setting unit. Based on each width in the orthogonal direction of one MPR section, a slice region setting unit for setting a slice region and the slice region setting unit set the slice region According serial slice area, having an imaging execution unit for executing the imaging for diagnosis of the required site.

  According to the magnetic resonance imaging apparatus of the present invention, it is possible to improve the operability of the operator when setting the slice region.

  An embodiment of a magnetic resonance imaging (MRI) apparatus according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing a configuration of an embodiment of an MRI apparatus according to the present invention.

  FIG. 1 shows an MRI apparatus 10 of this embodiment that performs imaging while continuously moving a patient (subject) P. FIG. The MRI apparatus 10 mainly includes an imaging system 11 and a control system 12.

  The imaging system 11 of the MRI apparatus 10 is provided with a gantry (not shown), a static magnetic field magnet 21 in the gantry, and a cylindrical shape coaxially with the static magnetic field magnet 21 inside the static magnetic field magnet 21. The shim coil 22 and the gradient magnetic field coil unit 23 formed in a cylindrical shape inside the static magnetic field magnet 21 are accommodated. Further, the imaging system 11 is provided with an RF coil 24 that transmits a radio frequency (RF) signal having a Larmor frequency (resonance frequency) and a bed mechanism 25 that moves the patient P back and forth in the gantry.

  On the other hand, the control system 12 of the MRI apparatus 10 includes a static magnetic field power supply 31, a gradient magnetic field power supply 32, a shim coil power supply 33, a transmitter 34, a receiver 35, a sequence controller (sequencer) 36, and a computer 37.

  The static magnetic field magnet 21 is connected to a static magnetic field power supply 31. A static magnetic field is formed in the imaging region (FOV: field of view) by the current supplied from the static magnetic field power supply 31.

  The shim coil 22 is connected to a shim coil power source 33 and supplies current to the shim coil 22 from the shim coil power source 33 to make the static magnetic field uniform.

  The gradient coil unit 23 includes an X-axis gradient coil 23x, a Y-axis gradient coil 23y, and a Z-axis gradient coil 23z. Further, a top plate 26 of the bed mechanism 25 is provided inside the gradient magnetic field coil unit 23, and the patient P is placed on the top plate 26. The top plate 26 is moved by the bed mechanism 25.

  The gradient magnetic field coil unit 23 is connected to a gradient magnetic field power supply 32. The X axis gradient magnetic field coil 23x, the Y axis gradient magnetic field coil 23y, and the Z axis gradient magnetic field coil 23z of the gradient magnetic field coil unit 23 are respectively an X axis gradient magnetic field power source 32x, a Y axis gradient magnetic field power source 32y, and a Z axis. Each is connected to a gradient magnetic field power supply 32z.

  The X-axis gradient magnetic field power source 32x, the Y-axis gradient magnetic field power source 32y, and the Z-axis gradient magnetic field power source 32z are supplied with currents supplied to the X-axis gradient magnetic field coil 23x, the Y-axis gradient magnetic field coil 23y, and the Z-axis gradient magnetic field coil 23z, respectively. 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 region, respectively.

  The RF coil 24 is a multi-coil and is connected to the transmitter 34 and the receiver 35. The RF coil 24 receives a high-frequency signal from the transmitter 34 and transmits a high-frequency magnetic field pulse to the patient P. The RF coil 24 receives an NMR signal generated by excitation of the nuclear spin inside the patient P by the high-frequency signal. 35. The transmission / reception system of the RF coil 24 can be classified into a system in which the transmission coil and the reception coil are combined with one coil, and a system in which separate coils are used for the transmission coil and the reception coil. In addition, although the RF coil 24 is provided in the MRI apparatus 10, only the head coil as an example of the RF coil 24 is illustrated in FIG.

  On the other hand, the sequence controller 36 of the control system 12 is connected to the bed mechanism 25, the gradient magnetic field power supply 32, the transmitter 34 and the receiver 35. The sequence controller 36 includes a processor (not shown) such as a CPU (central processing unit) and a memory, and control information necessary for driving the bed mechanism 25, the gradient magnetic field power source 32, the transmitter 34, and the receiver 35, 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 32 is stored.

  The sequence controller 36 drives the bed mechanism 25 in accordance with the stored predetermined sequence, thereby moving the table 26 forward and backward with respect to the gantry in the Z-axis direction. Further, the sequence controller 36 drives the gradient magnetic field power source 32, the transmitter 34, and the receiver 35 according to the stored predetermined sequence, thereby causing the X-axis gradient magnetic field Gx, the Y-axis gradient magnetic field Gy, and the Z-axis gradient magnetic field to be placed in the gantry. Gz and RF signals are generated.

  The transmitter 34 provides an RF signal to the RF coil 24 based on the control information received from the sequence controller 36. On the other hand, the receiver 30 performs necessary signal processing on the NMR signal received from the RF coil 24 and performs A / D (analog to digital) conversion, thereby obtaining a raw NMR signal that is digitized from the receiver 35. Data (raw data) is generated. The generated raw data is given to the sequence controller 36. The sequence controller 36 receives the raw data from the receiver 35 and gives it to the computer 37.

  The computer 37 includes basic hardware as a computer, such as a CPU 51 as a processor, a memory 52, an HD (hard disk) 53, an IF (interface) 54, an input device 55, and a display device 56. The CPU 51 is interconnected to each hardware component 52, 53, 54, 55, and 56 constituting the computer 37 via a bus B as a common signal transmission path. The computer 37 is connected to a network N such as a hospital backbone LAN (local area network) via the IF 54 so as to be capable of mutual communication. The computer 37 may include a drive for reading various application programs and data from a medium storing various application programs and data.

  The CPU 51 executes a program stored in the memory 52. Alternatively, the CPU 51 loads the program stored in the HD 53, the program transferred from the network N, received by the IF 54 and installed in the HD 53 into the memory 52 and executes it.

  The memory 52 has elements such as a ROM (read only memory) and a RAM (random access memory), and stores an initial program loading (IPL), a basic input / output system (BIOS), and a work memory of the CPU 51. This is a storage device used for temporary storage of data.

  The HD 53 is composed of a metal disk coated or vapor-deposited with a magnetic material, and is incorporated in a reading device (not shown) in a non-detachable manner. The HD 53 is a storage device that stores programs (including an OS (operating system) in addition to application programs) and data installed in the computer 37. In addition, the OS can be provided with a graphical user interface (GUI) that can use the graphics for displaying information to the user and perform basic operations with the input device 55.

  The IF 54 is a communication control device that performs communication control according to each standard. The computer 37 can be connected to the network N through the IF 54.

  Examples of the input device 55 include a keyboard, a mouse, and a joystick that can be operated by an operator such as an engineer. An input signal according to the operation is sent to the CPU 51.

  The display device 56 includes an image synthesis circuit, a D / A conversion circuit, a monitor, and the like, and displays an MRI image via the monitor.

  FIG. 2 is a block diagram showing functions of the MRI apparatus 10 of the present embodiment.

  When the CPU 51 executes the program, as shown in FIG. 2, the MRI apparatus 10 includes an original image generation unit 61, an orthogonal image generation unit 62, a first MPR cross section setting unit 63, a first MPR image generation unit 64, and a second MPR cross section. It functions as a setting unit 65, a second MPR image generation unit 66, a slice region setting unit 67, an imaging execution unit 68, and an image display control unit 69. In addition, although it demonstrates as the case where the components 61 thru | or 69 of the MRI apparatus 10 are functioned as software, the part or all of the components 61 thru | or 69 may be provided in the MRI apparatus 10 as a circuit. Further, the orthogonal image generation unit 62 is not an essential component for the MRI apparatus 10.

  The original image generation unit 61 has a function of generating an original image that is a cross-sectional image by controlling the sequence controller 36 to perform imaging for setting a slice region for a required part of the patient P. Specifically, the original image generation unit 61 generates one cross-sectional image as an original image among three orthogonal cross-sectional images of a coronal (CO) image, an axial (AX) image, and a sagittal (SG) image. Here, the original image generation unit 61 will be described as generating a sagittal image as an original image.

  The orthogonal image generation unit 62 has a function of generating, based on the original image generated by the original image generation unit 61, an orthogonal cross section that is a cross-sectional image of two cross sections orthogonal to the original image. For example, the orthogonal image generation unit 62 reconstructs a coronal image and an axial image that are other orthogonal three-section images based on the sagittal image generated by the original image generation unit 61.

  The first MPR section setting unit 63 has a function of setting a first MPR (multi-planar reconstruction) section that is orthogonal to the section of the original image generated by the original image generation unit 61. For example, the first MPR section setting unit 63 sets a first MPR section that is orthogonal to the section of the sagittal image generated by the original image generation unit 61. When the orthogonal image generation unit 62 is included, the first MPR cross-section setting unit 63 includes three cross-sections of the original image generated by the original image generation unit 61 and the two orthogonal images generated by the orthogonal image generation unit 62. A first MPR cross section orthogonal to the cross section of at least one cross section image is set. For example, when the orthogonal image generation unit 62 is included, the first MPR cross-section setting unit 63 generates at least one cross-sectional image among three cross-sectional images including a sagittal image as an original image and a coronal image and an axial image as an orthogonal image. A first MPR cross section orthogonal to the cross section is set.

  The first MPR image generation unit 64 has a function of generating a first MPR image in the first MPR section set by the first MPR section setting unit 63.

  The second MPR section setting unit 65 sets two sections each including two parallel straight lines set on the first MPR section set by the first MPR section setting unit 63 as two second MPR sections. It has a function.

  The second MPR image generation unit 66 has a function of generating two second MPR images in the two second MPR cross sections set by the second MPR cross section setting unit 65, respectively. The second MPR image is used as a so-called positioning image for setting and changing the slice area.

  The slice region setting unit 67 sets a slice region based on the respective widths in the orthogonal direction of the first MPR cross sections set on the two second MPR cross sections set by the second MPR cross section setting unit 65, respectively. It has a function.

  The imaging execution unit 68 has a function of executing imaging for diagnosis of a required part in accordance with the slice region set by the slice region setting unit 67.

  The image display control unit 69 has a function of controlling the display of the cross-sectional images output from the original image generation unit 61, the first MPR image generation unit 64, and the second MPR image generation unit 66 on the display device 56. In addition, when the orthogonal image generation unit 62 is included, the image display control unit 69 has three cross-sectional images of the original image generated by the original image generation unit 61 and the two orthogonal images generated by the orthogonal image generation unit 62. A function of controlling display of at least one cross-sectional image on the display device 56. Further, the image display control unit 69 displays the command input from the input device 55 on the display device 56 during the setting process by the first MPR cross-section setting unit 63, the second MPR cross-section setting unit 65, and the slice region setting unit 67. It has a function to control.

  Next, functions of the components 61 to 70 of the MRI apparatus 10 will be specifically described.

  First, imaging for positioning the patient P with respect to a required part is performed. In the imaging, an operator such as an engineer places the patient P on the top plate 26 and puts the patient P placed on the top plate in a gantry that is a static magnetic field space to which a static magnetic field is applied by the static magnetic field magnet 21. insert. Thereby, a static magnetic field is applied to the patient P. In this state, the operator confirms that the patient P is surely inserted, and inputs an instruction to start imaging using the input device 55. In response to the input, the CPU 51 executes the program.

  The original image generation unit 61 applies a gradient magnetic field and a high frequency pulse to the patient P via the sequence controller 36 at a predetermined timing. Correspondingly, the RF coil 24 receives a magnetic resonance signal. Based on the signal received from the sequence controller 36, a sagittal image as an original image is generated. The image display control unit 69 displays the sagittal image as the original image output from the original image generation unit 61 on the monitor of the display device 56. In addition, when the orthogonal image generation unit 62 is included, the image display control unit 69 has three cross sections: a sagittal image generated by the original image generation unit 61, and a coronal image and an axial image generated by the orthogonal image generation unit 62. At least one cross-sectional image of the images is displayed on the monitor of the display device 56.

  FIGS. 3 to 5 and 8 are schematic diagrams illustrating an example of a display screen of a cross-sectional image displayed on the monitor of the display device 56. FIG. 3 shows a three-screen display screen of a sagittal image, a coronal image, and an axial image of the head of the patient P displayed on the monitor of the display device 56. As shown in FIG. 3, the coronal image shows an XZ sectional image, the sagittal image shows a YZ sectional image, and the axial image shows an XY sectional image. Note that icons or the like that can set / change slice conditions (slice thickness, number of slices, and slice length) and the like may be displayed together on the display screen shown in FIG.

  Further, the first MPR section setting unit 63 shown in FIG. 2 sets a section that includes a straight line commanded on the section image displayed on the monitor of the display device 56 and is orthogonal to the section image as the first MPR section. . Specifically, as shown in the display screen of FIG. 4, one cross-sectional image of the sagittal image, coronal image, and axial image displayed by the operator on the monitor of the display device 56 using the input device 55, for example, sagittal By inputting a command of the straight line L1 on the image, the first MPR cross section setting unit 63 sets a cross section (UV cross section) that includes the straight line L1 and is orthogonal to the sagittal image as the first MPR cross section. The first MPR image generation unit 64 generates a first MPR image in the first MPR section. Furthermore, as illustrated in FIG. 4, the image display control unit 69 causes the display device 56 to display the first MPR image generated by the first MPR image generation unit 64.

  Further, as shown in the display screen of FIG. 5, the operator inputs a straight line L2 on the first MPR image displayed on the monitor of the display device 56 using the input device 55, whereby the second MPR cross-section setting unit. 65 includes two opposing straight lines of a quadrangle Q having a straight line L2 as a diagonal line inputted on the first MPR image displayed by the image display control unit 69 and orthogonal to the first MPR image. The cross section is set as the second MPR cross section.

  6 and 7 are schematic views showing a second MPR section. FIG. 6 shows an example of two cross sections including the two opposing straight lines of the quadrangle Q (second MPR cross section F1-second MPR cross section F2), and FIG. 2 shows another example of the two cross sections including the second MPR cross section F3 and the second MPR cross section F4.

  The second MPR image generator 66 shown in FIG. 2 generates two second MPR images in the two second MPR sections set by the second MPR section setting unit 65. Further, as shown in the display screen of FIG. 8, the image display control unit 69 displays the two second MPR images (second MPR sections F3 and F4) generated by the second MPR image generation unit 66 on the display device 56. To display.

  The slice area setting unit 67 shown in FIG. 2 sets the slice area based on the respective widths respectively inputted by commands on the two second MPR images displayed by the image display control unit 69. Specifically, as shown in the display screen of FIG. 8, the operator inputs the designation lines W1 and W2 on the second MPR image of the cross section F3 displayed on the monitor of the display device 56 using the input device 55. On the other hand, by inputting the designation lines W3 and W4 on the second MPR image of the cross section F4, the slice region setting unit 67 causes the width W1-2 between the designation lines W1 and W2 and the designation lines W3 and W3. Based on the width W3-4 sandwiched between W4, a slice region formed in the widths W1-2 and W3-4 is set in a space sandwiched between the second MPR cross sections F3 and F4.

  The operator inputs an instruction to start imaging using the input device 55 while the patient P is placed on the top plate 26. The imaging execution unit 68 shown in FIG. 2 executes imaging for diagnosis of a required part via the sequence controller 36 in accordance with the slice area set by the slice area setting unit 67.

  Here, when the width W1-2 and the width W3-4 are equal, as shown in FIG. 9, all the slice planes formed in the slice region are orthogonal to the second MPR cross sections F1 and F2. That is, when the width W1-2 and the width W3-4 are equal, all slice planes are formed in parallel. In other words, when it is desired to form all slice planes in parallel, the operator may set the width W1-2 and the width W3-4 to be equal on the display screen shown in FIG. When all the slice planes are formed in parallel, when the operator inputs the designation lines W1, W2, and W3 on the display screen shown in FIG. 8, the width W1-2 from the designation lines W1, W2 is changed to the width W1-2. The width W3-4 is set from the designation line W3.

  On the other hand, when the width W1-2 and the width W3-4 are not equal, as shown in FIG. 10, each slice plane formed in the slice region corresponds to the difference between the width W1-2 and the width W3-4. And formed into a fan shape. In addition, when the width W1-2 and the width W3-4 are not equal, as shown in FIG. 11, each slab formed by a plurality of slice surfaces formed in the slice region has a width W1-2 and a width W3. It is formed in a fan shape according to the difference from -4.

  According to the MRI apparatus 10 of the present embodiment, two second MPR images in two cross sections each including two parallel straight lines set on the first MPR cross section and orthogonal to the first MPR cross section are displayed. Based on these two second MPR images, a slice region can be visually set. Therefore, according to the MRI apparatus 10 of the present embodiment, it is possible to improve the operability of the operator when setting the slice area.

Schematic which shows the structure of embodiment of the MRI apparatus which concerns on this invention. The block diagram which shows the function of the MRI apparatus of this embodiment. The schematic diagram which shows an example of the display screen of the cross-sectional image displayed on the monitor of a display apparatus. The schematic diagram which shows an example of the display screen of the cross-sectional image displayed on the monitor of a display apparatus. The schematic diagram which shows an example of the display screen of the cross-sectional image displayed on the monitor of a display apparatus. The schematic diagram which shows a 2nd MPR cross section. The schematic diagram which shows a 2nd MPR cross section. The schematic diagram which shows an example of the display screen of the cross-sectional image displayed on the monitor of a display apparatus. The schematic diagram which shows an example of the slice surface in a slice area | region. The schematic diagram which shows an example of the slice surface in a slice area | region. The schematic diagram which shows an example of the slice surface in a slice area | region.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 MRI apparatus 11 Imaging system 12 Control system 36 Sequence controller 37 Computer 51 CPU
52 Memory 55 Input Device 56 Display Device 61 Original Image Generation Unit 62 Orthogonal Image Generation Unit 63 First MPR Section Setting Unit 64 First MPR Image Generation Unit 65 Second MPR Section Setting Unit 66 Second MPR Image Generation Unit 67 Slice Area Setting Unit 68 Imaging Execution Unit 69 Image display control unit

Claims (7)

An original image generation unit that performs imaging for positioning with respect to a required part of the subject and generates an original image that is a cross-sectional image;
Based on the original image generated by the original image generation unit, an orthogonal image generation unit that generates two orthogonal images that are two cross-sectional images orthogonal to the original image, and
A first MPR that is orthogonal to a cross section of at least one cross-sectional image among three cross-sectional images of the original image generated by the original image generation unit and the two orthogonal images generated by the orthogonal image generation unit. A first MPR cross-section setting unit for setting a (multi-planar reconstruction) cross-section;
A first MPR image generator for generating a first MPR image in the first MPR slice set by the first MPR slice setting unit;
The two second MPR cross sections are two cross sections each including two parallel straight lines set on the first MPR cross section set by the first MPR cross section setting section and orthogonal to the first MPR cross section. A second MPR cross-section setting unit set as
A second MPR image generation unit that generates two second MPR images in the two second MPR cross sections set by the second MPR cross section setting unit;
An image display control unit that controls display of the two second MPR images generated by the second MPR image generation unit;
A slice region setting unit for setting a slice region based on each width in the orthogonal direction of the first MPR cross section set on each of the two second MPR cross sections set by the second MPR cross section setting unit; ,
In accordance with the slice region set by the slice region setting unit, an imaging execution unit that executes imaging for diagnosis of the required part;
A magnetic resonance imaging apparatus comprising: The image display control unit controls display of at least one cross-sectional image among the three cross-sectional images, and the first MPR cross-section setting unit is input on the cross-sectional image displayed by the image display control unit magnetic resonance imaging apparatus according to claim 1, wherein the cross section perpendicular to the cross-sectional image includes a straight line, characterized by a circuit which sets, as the first MPR slice. The image display control unit controls display of the first MPR image generated by the first MPR image generation unit, and the second MPR section setting unit displays the first MPR image displayed by the image display control unit. magnetic resonance imaging apparatus according to claim 1, the two opposing sides of the rectangle that a straight line inputted on the MPR image diagonal, characterized in that a structure to be set as the two straight lines. The slice region setting unit is configured to determine the slice region based on each width in the orthogonal direction of the first MPR cross section input on the two second MPR images displayed by the image display control unit. The magnetic resonance imaging apparatus according to claim 1 , wherein the magnetic resonance imaging apparatus is configured to be set. Wherein when the width is equal, the imaging execution unit, a magnetic resonance according to claim 1, characterized in that a configuration for executing the imaging so as to parallel to all the slice plane of the slice area Imaging device. When the respective widths are not equal, the imaging execution unit is configured so that a space between two adjacent slice planes in the slice area is formed in a fan shape according to the difference in the widths . The magnetic resonance imaging apparatus according to claim 1 , wherein the imaging is performed on a plurality of slice planes . When the widths are not equal, the imaging execution unit uses a plurality of slice planes in the slice region as slabs, and a space between two adjacent slabs in the slice region corresponds to the difference in the widths. The magnetic resonance imaging apparatus according to claim 1 , wherein the imaging is performed on a plurality of slabs in the slice region so as to form a fan shape.

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