JP5433130B2 - Magnetic resonance imaging system - Google Patents

Description

  The present invention relates to a magnetic resonance imaging apparatus.

  A magnetic resonance imaging (hereinafter referred to as MRI) apparatus resonates the energy of a high-frequency magnetic field that rotates at a specific frequency when a group of nuclei having a specific magnetic moment is placed in a uniform static magnetic field. It is a device that visualizes chemical and physical microscopic information of a substance or observes a chemical shift spectrum by utilizing a phenomenon of absorption.

  In such an MRI apparatus, positioning for determining an imaging position necessary for diagnosis is often performed. In such positioning, first, imaging for positioning is performed to create a multi-slice image. Next, a region of interest (referred to as ROI) having a predetermined shape is set for the generated multi-slice image, and positioning is performed by selecting an image of a desired cross section within this ROI. Here, conventionally, the shape of the ROI at the time of positioning can be arbitrarily set by an operator such as a doctor in charge of the subject or a laboratory technician such as a rectangle, a line, a sphere, etc. according to the shape of the target region. is there. In Patent Document 1, an ROI having a three-dimensional structure is set, and this ROI is displayed on different display areas on a display screen together with a plurality of different three-direction cross-sectional images (axial image, sagittal image, coronal image). In addition, a line segment indicating a surface intersecting each surface is displayed on the ROI for each displayed cross-sectional image.

Furthermore, in positioning, a process called screening (image turning) is performed in which a doctor or the like searches for a desired cross-sectional image by continuously displaying cross-sectional images in the same direction on the display screen. . In general, during screening, a process of switching display images is performed while an ROI having a shape set before screening is displayed on the screen.
JP 2004-73379 A

  Here, in the conventional method of Patent Document 1 or the like, the ROI shape at the time of positioning is common regardless of all display areas of the display screen, the contents of display processing such as screening, and the like. For this reason, for example, in the case of FIG. 4, even if the ROI has no problem in the large display area 201, the observation part in the image is obscured by the ROI and difficult to see in the small display area 202. Can be considered. In addition, even when the display area is a large display area, when crossing plane display or the like is performed, there is a possibility that image observation may be hindered during screening.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a magnetic resonance imaging apparatus capable of setting an ROI having an appropriate shape in accordance with display conditions of an image being positioned.

In order to achieve the above object, a magnetic resonance imaging apparatus according to claim 1 of the present invention displays a plurality of cross-sectional images in different directions obtained by imaging a subject in different display areas. and means, and control means for superimposing the omission region of interest slice line indicating a slice position in the case of turning images in each image, the control means, the region of interest during the image turning, It is characterized by setting to intersect line display .

In order to achieve the above object, a magnetic resonance imaging apparatus according to claim 6 of the present invention displays images in a plurality of cross sections in different directions obtained by imaging a subject in a plurality of different display areas. And display means for superimposing a display for indicating each slice position of the image in the cross section on the respective images. The control means is arranged on the display means in the same direction of the subject. When receiving an instruction for screening for sequentially displaying cross-sectional images, the display means performs a display in which the positions other than the representative positions of the imaging regions of the sequentially displayed images are omitted.

According to these magnetic resonance imaging apparatuses according to claims 1 and 6 , the region of interest is accurately positioned by setting the shape of the region of interest according to the display conditions of the images displayed in the display region of the display means. There is no hindrance.

  ADVANTAGE OF THE INVENTION According to this invention, the magnetic resonance imaging apparatus which can set ROI of a suitable shape according to the display conditions of the image in positioning can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a configuration of a magnetic resonance imaging (MRI) apparatus according to an embodiment of the present invention. In FIG. 1, a static magnetic field magnet 1, a gradient magnetic field coil 2, and an RF coil 3 are provided in order from the outside in a gantry 20 in which a cylindrical imaging space is formed so as to accommodate a subject P at the center. ing. The static magnetic field magnet 1, the gradient magnetic field coil 2, and the RF coil 3 are attached to the gantry 20 by a support member (not shown). The static magnetic field magnet 1 generates a static magnetic field in the imaging space along the Z axis that is the body axis direction of the subject, and is configured using, for example, a superconducting coil or a normal conducting coil. The gradient coil 2 has an X-axis gradient magnetic field whose magnetic field strength changes linearly along the X-axis, a Y-axis gradient magnetic field whose magnetic field strength changes linearly along the Y-axis, and a magnetic field strength linearly along the Z-axis. The Z coil set, the X coil set, and the Y coil set are configured so that the changing Z-axis gradient magnetic field can be independently generated. The RF coil 3 generates a high-frequency magnetic field (RF pulse) that acts on the magnetization spin of a nuclide to be diagnosed in the subject P, and is used to detect an echo signal generated by magnetic resonance. The subject P on the bed 15 is inserted into an imageable region in the gantry 20 (a spherical region where an imaging magnetic field is formed, and diagnosis is possible only in this region).

  The static magnetic field magnet 1 is driven by a static magnetic field control device 4. The RF coil 3 is driven by the transmitter 5 when magnetic resonance is excited, and is coupled to the receiver 6 when an echo signal is detected. The X coil set, Y coil set, and Z coil set of the gradient magnetic field coil 2 are driven by an X axis gradient magnetic field power source 7, a Y axis gradient magnetic field power source 8, and a Z axis gradient magnetic field power source 9, respectively.

  The X-axis gradient magnetic field power supply 7, the Y-axis gradient magnetic field power supply 8, the Z-axis gradient magnetic field power supply 9, and the transmitter 5 are driven according to a predetermined sequence by the sequencer 10, and are respectively X-axis gradient magnetic field, Y-axis gradient magnetic field, and Z-axis gradient magnetic field. A magnetic field and an RF pulse are generated according to a predetermined pulse sequence. In this case, the X-axis gradient magnetic field, the Y-axis gradient magnetic field, and the Z-axis gradient magnetic field are mainly used as, for example, a frequency encoding gradient magnetic field, a readout gradient magnetic field, a phase encoding gradient magnetic field, or a slice gradient magnetic field, respectively. . The computer system 11 drives and controls the sequencer 10, captures an echo signal as an echo signal received by the receiver 6, and performs predetermined signal processing to generate a tomographic image of the subject, and the generated tomographic image Is displayed on the display unit 12 as display means. The operation unit 13 is various operation members such as a mouse for inputting an operation by an operator to the computer system 11. The storage unit 14 is a storage unit such as a hard disk for the computer system 11 to store information.

  Hereinafter, the operation of the present embodiment will be described. FIG. 2 is a cross-sectional image obtained by multi-slice imaging for positioning by the MRI apparatus having the configuration of FIG. 1 and a table of regions of interest (ROI) set for the cross-sectional image displayed on the display unit 12. It is a figure shown about an example. In the example of FIG. 2, cross-sectional images (axial image, coronal image, sagittal image) in three different directions are generated and displayed from an image obtained by imaging for positioning. Here, the axial image is a cross-sectional image (an image on the XY plane) perpendicular to the body axis (Z-axis) direction of the subject P. The coronal image is an image of a cross section (an image on the ZX plane) parallel to the front surface of the subject P and perpendicular to the axial image. Further, the sagittal image is an image of a cross section perpendicular to both the axial plane and the coronal plane (an image on the YZ plane). In FIG. 2, the display area of the display unit 12 is divided into three, and the operation area by the operator among the three-direction cross-sectional images obtained by multi-slice imaging for positioning is displayed in the display area 101. The image of the cross section selected by the operation 13 is displayed, and the remaining cross-sectional images are displayed in the display areas 102 and 103. FIG. 2 shows an example in which the diagnosis site of the subject P is the head. A coronal image is displayed in the display area 101, and a sagittal image and an axial image are displayed in the display areas 102 and 103, respectively. Here, the image of the cross section displayed on the display unit 12 is not limited to the axial image, the coronal image, and the sagittal image, and an image of the cross section in any direction other than the axial surface, the coronal surface, and the sagittal surface (oblique image) is displayed. You may make it let it.

  Furthermore, in FIG. 2, the region of interest (ROI) set by the operation of the operation unit 13 by the operator is superimposed and displayed on the cross-sectional images displayed in each display region. Here, in the present embodiment, based on the shape of the ROI set by the operator, the ROI that is actually displayed in each display area of the display unit 12 according to the display condition of the cross-sectional image displayed on the display unit 12. Set the shape. Such setting is performed by the computer system 11 as a control means.

  As shown in FIG. 2, the display area 101 is larger than the other display areas, and can display a relatively large screen. In such a large display area, there is little possibility that it is difficult to see the observation site in the image even if the ROI shape is relatively complicated. Therefore, for example, in the example of FIG. 2, the shape of the ROI is set to a shape indicated by reference numeral 101a. The ROI 101a performs a display indicating the shooting range of the axial image and a cross-plane display indicating the slice position of each axial image with respect to the coronal image displayed in the display area 101. By setting the ROI having such a shape, the operator can confirm the slice position of another cross-sectional image (axial image) while observing the observation site in the image displayed in the display area 101. .

  On the other hand, since the display area 102 is smaller than the display area 101, if the same cross plane display as that of the display area 101 is performed, there is a possibility that the observation site is hidden by the cross plane display and is difficult to see. Therefore, the display area 102 does not perform the intersection plane display, and displays the axial image capturing range and its center position as shown by reference numeral 102a in FIG. By setting the ROI having such a shape, the operator can appropriately view the observation site even in a small display area and can also check the imaging range of the axial image.

  Here, when the cross-sectional image to be displayed in the display area 101 is switched by the operation of the operation unit 13 by the operator, the shape of the ROI is switched accordingly.

  In FIG. 2, the ROI of the cross-sectional image in the display area 103 is indicated by reference numeral 103a. This ROI 103a is for indicating the slice position of the axial image. In the case of this shape of ROI, the observation site is not hidden, so there is no need to change the shape of the ROI to another shape.

  In the example of FIG. 2, the display areas 102 and 103 have the same size, but the sizes may be different. Further, if the display screen of the display unit 12 is sufficiently large and display like the display area 101 can be performed in all display areas, the ROI shape of all display areas may be the ROI 101a.

  FIG. 3 is a diagram illustrating a display example of an ROI when performing screening processing (image turning processing) in which images in the same cross-sectional direction are continuously displayed on the display unit 12 in the present embodiment. This screening process is performed when the operator performs an operation for executing the screening process while the screen as shown in FIG. 2 is displayed. In response to this operation, the computer system 11 continuously displays an image of a cross section (that is, an axial image) intersecting the cross section image currently selected by the operator in the display area 101 of the display unit 12.

  First, before starting the screening process, the ROI 101a set by the operator is displayed together with the axial image at the upper end position of the imaging range. Subsequently, an axial image is sequentially displayed for each slice position. At this time, the ROI is an intersecting plane display (intersecting line display) 101b, 101c, 101d indicating the representative position of the imaging area (FOV) of each imaging section. And Thereafter, after the screening process is completed, the original ROI 101a is displayed together with the axial image at the lower end position of the imaging region.

  By displaying such an ROI, it is possible to know which slice position image is currently displayed in the display area 101 during the screening process, and there is no possibility that the observation site is hidden by the ROI.

  After positioning, the imaging parameters (eg, TR (repetition time), TE (echo time), slice thickness, FOV (imaging area) set prior to positioning within the ROI set by the operator. ), Etc., tomographic imaging (main imaging) is performed. The ROI may be automatically set at a more appropriate position as compared with the past ROI based on the ROI set by the operator.

  As described above, according to the present embodiment, the ROI is displayed by setting the ROI according to the display condition of the cross-sectional image such as the size of the display area of the display unit 12 and whether or not the screening process is performed. Therefore, the observation site is not hidden and cannot be seen, and accurate positioning operation is not hindered.

  Although the present invention has been described based on the above embodiments, the present invention is not limited to the above-described embodiments, and various modifications and applications are naturally possible within the scope of the gist of the present invention. For example, in this embodiment, the computer system 11 automatically sets the ROI shape to be displayed in each display area. However, the ROI shape is set for each display area by the operation of the operation unit 13 by the operator. You may be able to do it. In this case, the shape of the ROI for each display area set by the operator may be stored in the storage unit 14, for example, and the shape of the ROI stored in the storage unit 14 may be set at the next display. .

  Furthermore, the shape of the ROI may be set according to the imaging section direction, or may be set according to the shape of the observation site.

  Further, the above-described embodiments include various stages of the invention, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some configuration requirements are deleted from all the configuration requirements shown in the embodiment, the above-described problem can be solved, and this configuration requirement is deleted when the above-described effects can be obtained. The configuration can also be extracted as an invention.

It is a figure which shows the structure of the magnetic resonance imaging apparatus which concerns on one Embodiment of this invention. It is a figure shown about the example of a display of the region of interest set with respect to the image of the cross section displayed on a display part, and the image of a cross section in one Embodiment of this invention. In one Embodiment of this invention, it is a figure shown about the example of a display of the region of interest in the case of performing a screening process. It is a figure shown about the example of a display of the region of interest set with respect to the image of a cross section displayed on a display part, and the image of a cross section in a prior art example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Static magnetic field magnet, 2 ... Gradient magnetic field coil, 3 ... RF coil, 4 ... Static magnetic field control apparatus, 5 ... Transmitter, 6 ... Receiver, 7 ... X-axis gradient magnetic field power supply, 8 ... Y-axis gradient magnetic field power supply, DESCRIPTION OF SYMBOLS 9 ... Z-axis gradient magnetic field power supply, 10 ... Sequencer, 11 ... Computer system, 12 ... Display part, 13 ... Operation part, 14 ... Memory | storage part, 15 ... Bed, 20 ... Gantry

Claims (6)

Display means for displaying images in cross sections in a plurality of different directions obtained by imaging a subject in a plurality of different display areas,
And control means for superimposing the omission region of interest slice line indicating a slice position in the case of turning images in each image,
Comprising
The magnetic resonance imaging apparatus characterized in that the control means sets the region of interest to intersect line display when the image is turned .   The magnetic resonance imaging apparatus according to claim 1, wherein the control unit sets the region of interest according to an observation site of the subject. A storage means for storing the setting of the shape of the set region of interest,
  The magnetic resonance imaging apparatus according to claim 1, wherein the control unit sets the region of interest according to a setting stored in the storage unit. The magnetic resonance imaging apparatus according to claim 1, further comprising an operation unit for manually setting the region of interest for each image. The magnetic resonance imaging apparatus according to claim 1, wherein the region of interest is a region of interest for positioning for determining an imaging position of the subject. Display means for displaying images in cross sections in a plurality of different directions obtained by imaging a subject in a plurality of different display areas,
Control means for superimposing a display for indicating each slice position of the image in the cross section on the respective images;
Comprising
When the control means receives a screening instruction for sequentially displaying images of cross-sections in the same direction of the subject on the display means, the control means omits a display other than the representative position of the imaging region of the sequentially displayed images. A magnetic resonance imaging apparatus characterized by being applied to a display means.

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