JP2003290171A - Mri unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an MRI unit which enables smooth setting in imaging by achieving a higher efficiency in the setting of sliced areas and saturation areas or other operations. <P>SOLUTION: A first and a second points are made indicative from an input device 14 on a saggital image previously taken and displayed on a display device 13 and the sliced areas parallel adjacent to each other are automatically set to perform an imaging of the sliced areas through a controller 7. Third and fourth points are made indicative following the first and second points and the imaging of the sliced areas thus set is also accomplished. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an MRI apparatus for taking a tomographic image which is substantially orthogonal to the tomographic image based on an imaging region set on the tomographic image of a subject.

[0002]

2. Description of the Related Art Conventionally, for example, MR of lumbar disc herniation
When diagnosing with the I device, it is known to image the cross section along the intervertebral disc. A method called a multi-angle multi-scan method is usually used for the cross-sectional imaging along the intervertebral disc. When imaging is performed using this method, as a preparatory step, a sagittal image of the vertebra of the subject is previously imaged as a positioning image, and a large number of slice areas are set on this sagittal image. By executing the scan of the set slice area using the multi-angle multi-scan method, a tomographic image of the set slice area is captured at one time. Further, in the clinical imaging of the herniated disc, in order to observe the up and down development of the herniated disc, a plurality of slice areas adjacent to each other in a substantially parallel manner along the disc are set.
Note that a plurality of slice areas that are adjacent to each other in parallel are called slabs.

Therefore, in clinical imaging of a herniated disc,
As shown in FIG. 8, slabs with different angles are set in different parts of the subject. Conventionally, as a method of setting such a plurality of slabs, an operator has performed the following operations. (1) Display the first slice area at a predetermined default position on the sagittal image. (2) The slice position, slice thickness, slice length, angle, etc. of the first slice area are adjusted using the mouse. (3) By setting the number of slice areas adjacent in parallel to the first slice area. Form a first slab. (4) Similar to the above, the second slice area is displayed. (5) Adjust the slice position, slice thickness, slice length, angle, etc. of the second slice area. (6) Form the second slab. By the above operation, the first slab (formed from two slice areas in the example) and the second slab shown in FIG.
Slab (formed of three slice areas in the example) is set.

In some cases, an area different from the slice area may be set. This is, for example, the setting of a region (so-called saturation region) that suppresses the influence of blood flow and the like. The saturation region is for suppressing a signal from the region by applying a high frequency pulse to the region in advance, and is generally set in advance when blood flow affects the image. . Conventionally, also in the setting of this saturation area, similarly to the setting of the slice area, first a saturation area with an appropriate angle and size is displayed as a default, and while rotating a part of this saturation area with the mouse, rotation etc. By doing so, the angle and size were set appropriately.

[0005]

However, in the imaging for observing the herniated intervertebral disc as described above, it is necessary to set a large number of slice areas, so a considerable amount of time is spent for this setting, and the setting efficiency is reduced. There was a problem. Also, in setting the saturation area,
When there are multiple saturation regions, it takes time to set them, and similarly the setting efficiency is lowered. Therefore, the present invention solves the above problems and improves the efficiency of slice area setting and saturation area setting,
It is an object of the present invention to provide an MRI device that can perform smooth imaging.

[0006]

In order to solve the above-mentioned problems, the invention according to claim 1 provides a plurality of second tomographic images substantially orthogonal to the first tomographic image of the subject. In an MRI apparatus for imaging based on each of a plurality of slice areas set on a tomographic image, setting means for setting the number of the slice areas, and a first point and a second point on the first tomographic image. And a designated means capable of designating the designated first
And an imaging area determining means for arranging the set number of slice areas adjacent to each other and substantially parallel to each other based on the second point. In addition, claim 2
In the MRI apparatus that captures a second tomographic image that is substantially orthogonal to the first tomographic image in a state where a saturated region set on the first tomographic image of the subject is saturated, Setting means for setting the width of the saturation region, designating means for designating a first point and a second point on the first tomographic image, and the designated first point and second point And a saturation region determining means for setting the saturation region based on the set width of the saturation region.

According to a third aspect of the present invention, a plurality of second tomographic images that are substantially orthogonal to the first tomographic image of the subject are taken as the first tomographic image.
In an MRI apparatus for imaging based on each of a plurality of slice areas set on one tomographic image, setting means for setting the number of the slice areas, and at least a first point on the first tomographic image, 2nd point, 3rd point and 4th point can be designated continuously, and said set number of slice areas based on said 1st and 2nd designated points, respectively. And substantially parallel to each other, and based on the designated third and fourth points, the imaging region determining means for arranging the set number of slice regions adjacent to each other and substantially parallel to each other. Characterize.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described in detail below with reference to the drawings. Figure 1
FIG. 3 is a block diagram of an MRI apparatus according to this embodiment.
This MRI apparatus includes a magnet unit for generating a static magnetic field, a gradient magnetic field unit for generating a gradient magnetic field for giving position information to the static magnetic field, a transmitter / receiver unit for magnetic excitation and NMR signal reception, and system control. And functionally has a control / arithmetic unit for data processing. Specifically, as shown in FIG. 1, the magnet portion includes, for example, a normal-conduction type magnet 1 and a static magnetic field power source 2 that supplies a current to the magnet 1, and an opening portion into which the subject P is inserted. A static magnetic field H0 is generated in the z-axis direction. Also,
The gradient magnetic field unit includes three pairs of gradient magnetic field coils 4 incorporated in the magnet 1 in the x, y, and z directions, and these gradient magnetic field coils 4
And a gradient magnetic field power source including a gradient magnetic field controller 6. Gradient magnetic field controller 6
Activates the drive circuit 5 according to the pulse sequence supplied from the main controller 7. As a result, a linear magnetic field is superimposed on the static magnetic field H0 in order to provide position information for imaging, and a gradient magnetic field is formed. The transmission / reception unit includes a transmission coil 8a and a reception coil 8b arranged to face the subject P in the opening of the magnet 1, and a transmitter 9 individually connected to the transmission coil 8a and the reception coil 8b. And a receiver 10. The transmitter 9 generates a high frequency pulse for exciting NMR based on a command from the control device 7. The receiver 10 is the NM obtained by the receiving coil 8b.
The R signal is detected and amplified, and the NMR signal is sent to the storage device 11 based on a command from the control device 7.

Further, the control / arithmetic unit includes a control device 7 connected to the transmitter 9, the receiver 10 and the gradient magnetic field control device 6, a storage device 11 for storing an NMR signal, and an operation command to the control device 7. And an arithmetic unit 12 for processing the stored signal of the storage unit 11, and a display unit 13 for display.
With. An input device 14 such as a keyboard and a mouse is connected to the arithmetic unit 12. The arithmetic unit 12 subjects the acquired NMR signal to a huge amount of arithmetic processing including Fourier transform and the like to generate image data. This image data is displayed on the display device 13 as needed. The arithmetic unit 12 also has a function of setting a slice area, a saturation area, and the like, which will be described later.

Next, the operation of this embodiment will be described with reference to FIGS. In addition, FIG.
FIG. 3 is a flowchart showing the setting procedure of the operator, and FIGS. 4 and 5 show part of the screen displayed on the display device 13 when setting the slice area. In addition, this Embodiment demonstrates the case where a disc herniation of a subject is imaged. In addition, the following (1)
Positioning image shooting prior to actual shooting, (2)
The description will be made in the order of setting the slice area for performing the main imaging, (3) setting the saturation area, and (4) performing the main imaging. (1) The operator of the positioning image lays the subject P on the top plate, and places the subject P together with the top plate in the gantry of the MRI apparatus, which is the static magnetic field space where the static magnetic field is applied by the magnet 1. insert. As a result, the static magnetic field is applied to the subject P. In this state, the operator confirms that the subject P has been reliably inserted, and issues an instruction to start imaging from the input device 14. In response to this, the arithmetic device 12 and the control device 7 apply the gradient magnetic field and the high frequency pulse to the subject at a predetermined timing via the gradient magnetic field coil 4 and the transmission coil 8a. Corresponding to this, the magnetic resonance signal is received by the receiving coil 8b,
In the arithmetic unit 12, the spine of the subject based on the received signal,
A sagittal image of a part including the lumbar spine is created. The created sagittal image is stored in the storage device 11 and displayed on the display device 13. This sagittal image is
It is used as a so-called positioning image such as setting of a slice area of an image (oblique image) orthogonal to a sagittal image described later, setting of a saturation area, and the like.

Further, the display device 13 displays a screen as shown in FIG. Explaining this screen, an area 23 in which a sagittal image of the imaged subject is displayed is provided in the lower right part of the figure. The spine of the subject is shown in the approximate center of the area 23. The area 22 at the upper right of the screen is an area in which a window for setting slice conditions (slice thickness, number of slices, slice length, etc.) is displayed. In the area 21 on the left side of the screen, a window for rotating and enlarging / reducing the image (sagittal image in this example) displayed in the area 23, or a window for switching the setting mode (described later) is displayed. Area. (2) Setting of Slice Area After shooting the sagittal image, the operator sets a slice area for main shooting on the sagittal image. Note that, while setting the slice area and setting the saturation area to be described later, the gradient magnetic field and the high frequency pulse are not applied to the subject P, and the patient P is kept in a standby state while being placed on the bed.

Specifically, the setting of the slice area is performed as shown in FIG.
The procedure is as shown in. First, in step S1, the captured sagittal image is displayed in the area 23 of FIG. 2 (specifically, it is automatically displayed after the sagittal image is captured). Next, in step S2, the operator sets slice conditions. Here, the setting of the slice condition is the setting of the slice thickness, slice length, the number of slices, etc. of the slice area in the actual imaging. Specifically, the area 22 in FIG.
Setting is performed by inputting a numerical value using a keyboard in a predetermined frame 24 provided in the window shown in, or by moving a bar 25 provided in the window with a mouse. Next, in step S3, a first point is set on the sagittal image. Specifically, using the mouse 14 of the input device 4, the point 32 is clicked as shown in FIG. The point to be clicked with the mouse can be any point on the sagittal image. The arrow shown in the figure is a pointer 31 that can be operated by a mouse, and the dotted line is a line connecting the point 32 designated first and the tip of the pointer 31. This dotted line is automatically displayed when the point 32 is designated.

Next, in step S4, when an appropriate point 33 on the sagittal image is clicked (the second point is designated), as shown in FIG.
2 and point 33, multiple slice areas 3 automatically
4 is displayed. Specifically, a straight line connecting the set two points is used as a center line, and the slice area is symmetrical with respect to the center line based on the preset slice conditions (slice number, slice thickness, slice length). Is set. Further, the center of this slice area matches the center of the set two points. In this way, the first slab 34 is formed. Further, the respective slice areas have the same thickness and the same length. Further, similar to the above, in step S5, the first point for setting the second slab is designated as shown in FIG. 5A, and then in step S6, as shown in FIG. Specify 2 points. At the same time when the second point is designated, the second slab 35 is set and automatically displayed.

The above is the setting of the slice area, and the position and angle of each set slab consisting of a plurality of slice areas are stored in the storage device 11 in FIG. In this embodiment, both the first and second slabs can be set under one slice condition. In addition, in the present embodiment, four points required for setting the first and second slabs can be continuously designated. (3) Setting of Saturation Area Next, setting of the saturation area will be described.
The saturation area may be set after the slice area is set or before the slice area is set. If it is not necessary to set it as the saturation region, this setting can be omitted. The mode for setting the slice area to the mode for setting the saturation area can be changed at any time by pressing a button in the window shown in the area 21 shown in FIG.

The specific saturation area setting is
The procedure is as shown in the flowchart of FIG. In step S1, the sagittal image is displayed in a predetermined area of the display device 13, similar to the setting of the slice area. More specifically, the image displayed when the slice area is set is maintained. Next, step S1
In 2, the saturation conditions are set.
Here, the saturation condition includes the width of the saturation region. After the saturation condition is set, in step S13, as shown in FIG. 7A, the first sagittal image is set on the sagittal image similarly to the setting of the slice area.
The point 42 is set. Then, in step S14, as shown in FIG.
The second point 43 is set as shown in (b). As a result, the saturation region 44 having a predetermined thickness is set according to the saturation condition. Specifically, the saturation region 44 has two set points (4
3, 44) is a symmetrical rectangular range with a straight line connecting the lines as the center line.

After the first saturation region is set in step S14, the second saturation region can be set in steps S15 and S16. Note that the saturation region can be set continuously as in the slice region setting. (4) Main Shooting Once the slice area and the saturation area have been set as described above, the main shooting is started according to an instruction from the operator. In the main imaging, the application strength and timing of the high-frequency pulse and the gradient magnetic field are set so that the imaging is performed as needed for each slice of the slab set in (2). Further, at this time, by applying a high frequency pulse to the saturation region set in (3) in advance, this region is saturated and the obtained magnetic signal is reduced. That is, the data regarding the setting of the slice region and the data regarding the setting of the saturation region are both used as data for determining the strength and timing of application of the high frequency pulse and the gradient magnetic field. The strength and timing of application of the high-frequency pulse and the gradient magnetic field are shown in FIG.
Done in. The image of the slice area obtained by the main photographing is selectively displayed in the area 23 of FIG. The operator observes and diagnoses the herniated disc while observing the image of the slice area.

In the present embodiment, the slab can be set only by setting the predetermined two points on the positioning image, and by setting the other two predetermined points,
A plurality of slabs can be continuously set, and the setting efficiency of the slice area can be significantly increased compared to the conventional case. Thereby, the imaging time of the patient can be shortened. Although the slice length is preset as the slice condition in the present embodiment, the length of two designated points may be set as the slice length. Further, in the present embodiment, the slab is set by designating two points, but the position, angle, etc. of the slab can be changed with a mouse or the like. Further, in the present embodiment, MRI having a cylindrical gantry
Although the apparatus has been described, the shape of the gantry and the direction of application of the static magnetic field are not limited, and it is applicable to a so-called open type MRI apparatus.

Although the respective embodiments of the present invention have been described above, the present invention may use only either the slice area setting or the saturation area setting, and is within the scope of the invention. The deformation of is also conceivable.

[0019]

As described in detail above, according to the present invention, by automatically specifying two points in a predetermined area setting, the time for specifying the area can be shortened. The setting efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram of an MRI apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a screen displayed by the display device according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing an operator setting procedure according to the first embodiment of the present invention.

FIG. 4 is a part of a screen displayed on a display device when setting a slice area according to the first embodiment of the present invention.

FIG. 5 is a part of a screen displayed on a display device when setting a slice area according to the first embodiment of the present invention.

FIG. 6 is a flowchart showing an operator setting procedure according to the first embodiment of the present invention.

FIG. 7 is a part of a screen displayed on the display device when the saturation is set in the first embodiment of the present invention.

FIG. 8 is a part of a screen displayed on a display device when setting a slice area.

[Explanation of symbols]

31 pointer 32 First point 33 Second point 34 First Slab 35 Second Slab 44 Saturation area

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Naoyuki Takabayashi             1385 Higashiyama, Shimoishi, Otawara, Tochigi Prefecture             Toshiba Nasu factory inside F-term (reference) 4C096 AB36 AB38 AD06 AD07 BA20                       BB13 BB14 BB16 BB19

Claims (4)

[Claims] 1. An MRI apparatus for imaging a plurality of second tomographic images substantially orthogonal to a first tomographic image of a subject based on each of a plurality of slice regions set on the first tomographic image, Based on setting means for setting the number of the slice areas, designating means capable of designating a first point and a second point on the first tomographic image, and based on the designated first and second points And an imaging region determining means for arranging the set number of slice regions adjacent to each other and substantially in parallel with each other. 2. An MRI apparatus for photographing a second tomographic image substantially orthogonal to the first tomographic image in a state where a saturated region set on the first tomographic image of the subject is saturated, Setting means for setting the width of the saturated region, and specifying means for specifying the first point and the second point on the first tomographic image,
An MRI apparatus, comprising: a saturated region determining unit that sets the saturated region based on the designated first and second points and the set width of the saturated region. 3. An MRI apparatus for photographing a plurality of second tomographic images substantially orthogonal to a first tomographic image of a subject on the basis of each of a plurality of slice areas set on the first tomographic image, Setting means for setting the number of the slice areas, and specifying means capable of continuously specifying at least a first point, a second point, a third point and a fourth point on the first tomographic image. , The set number of slice regions are arranged adjacent to each other substantially parallel to each other based on the designated first and second points, and the setting is performed based on the designated third and fourth points. And an imaging region determining means for arranging a predetermined number of slice regions adjacent to each other and substantially parallel to each other. 4. The designation means is capable of designating a fifth point and a sixth point, and the designated fifth point and sixth point are designated.
4. The MRI apparatus according to claim 3, further comprising a saturation area determining unit that sets the saturation area based on the point.