JP2003334175A - Magnetic resonance imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the central position of the static magnetic field of a unit coincide with that of a desired region of an examinee at any time. <P>SOLUTION: This MRI (magnetic resonance imaging) device equipped with a static magnetic field generating means for providing a static magnetic field to a subject 8, an inclined magnetic field generating means for providing an inclined magnetic field to the examinee 8, and a probe for irradiating a diagnostic region of the subject with high-frequency signals and receiving high-frequency signals emitted through the nuclear magnetic resonance by living tissue of the subject, is characterized in that, it is provided with a unit 9 which is composed of the static magnetic field generating means, the inclined magnetic field generating means, and also a means for making the unit 9 to follow any movement of a desired region to be imaged that accompanys the subject's moving, and the central position of the static magnetic field of the unit is made to always coincide with that of the desired region of the examinee. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] The present invention relates to a magnetic resonance imaging apparatus.
(Hereinafter, referred to as an MRI apparatus),
Generating means, the gradient magnetic field generating means and the probe are one unit.
A unit for imaging the unit with the movement of the subject
Follow the movement of the part you want to
The center position and the center position of the part of the subject
This is related to the technology for matching. [0002] 2. Description of the Related Art In a conventional MRI apparatus, a patient is
As it is confined in a closed space, feeling of occlusion and pressure
Pain may be felt by feeling. So, while shooting
Open MRI system that does not cause pain for some patients
Is being planned. This open type MRI apparatus is opened.
Since the patient can be accessed from the part,
Instructs the operator (technologist or doctor) of the tomographic plane easily using
And image the designated tomographic plane in real time.
Is being developed, and development as an I-MRI system is progressing.
(Nikki Medical Journal, Vol. 21, No. 5, 2001). A conventional MRI apparatus is, for example, shown in FIG.
As described above, a static magnetic field is applied to the subject 8 placed on the bed 12.
And a gradient magnetic field to the subject 8
The gradient magnetic field generating means 2 and the gradient magnetic field generating means
Gradient magnetic field power supply 3 and a high-frequency magnetic field
And nuclear magnetic resonance of the living tissue of the subject.
A probe 4 for receiving a high-frequency magnetic field emitted by
Static magnetic field generating means 1, gradient magnetic field generating means 2, and probe 4
High-frequency transmission for driving to emit and receive the high-frequency magnetic field
The control of the receiving unit 5, the gradient magnetic field power supply 3, and the high-frequency transmitting / receiving unit
Control according to the pulse sequence at the time of shooting, and
Image reconstruction operation using high frequency signal received by lobe
A computer 6 for performing the processing and an image signal generated by the computer 6
A display 7 for inputting and displaying as a tomographic image
ing. The size of the static magnetic field generating means of the conventional MRI apparatus
Although it is large enough to cover the entire subject,
The space provided for this purpose is small, and
You need to be almost stationary. Meanwhile, the whole-body type device
, Limited to local shooting of limbs, head, etc.
Stationary devices have been proposed. Also, with the improvement of photography technology,
And the shooting time has been reduced,
It is possible to observe in a mick. FIG. 6 shows a schematic configuration of a conventional MRI apparatus.
You. [0006] SUMMARY OF THE INVENTION
In the conventional whole body type MRI apparatus, the space given to the subject is
Because of the limited movement of the subject, joints such as wrists and ankles
Is limited to small movements that bend the
Was. Further, in the local-type apparatus, the empty space given to the subject is
It is said that the interval is further limited compared to whole body type MRI equipment
There was a problem. It is an object of the present invention to control walking, jumping, bending and stretching.
Technology that can observe the movement of a larger subject.
To provide. [0008] Another object of the present invention is to provide a surgical apparatus for an MRI apparatus.
Providing technologies that can expand applications
You. The above and other objects and novel features of the present invention
Features are apparent from the description of this specification and the accompanying drawings.
Will be. [0010] SUMMARY OF THE INVENTION The present invention is disclosed in the present application.
The outline of the invention is briefly described as follows.
  A first invention provides a static magnetic field generating means for applying a static magnetic field to a subject.
Step and gradient magnetic field generating means for applying a gradient magnetic field to the subject
A gradient magnetic field power supply for driving the gradient magnetic field generating means;
Irradiating a high-frequency signal to the diagnostic site of the subject
Both are released by nuclear magnetic resonance of the living tissue of the subject.
A probe for receiving a high-frequency signal, and driving the probe.
High-frequency transmission and reception for irradiating and receiving the high-frequency signal
Communication unit, and controls the gradient magnetic field power supply and the high-frequency transmission / reception unit.
It is performed according to the pulse sequence at the time of shooting and
Image reconstruction using the high-frequency signal received by the
And a table for displaying images generated by the computer.
MRI system (magnetic resonance imaging system) equipped with an indicator
And the static magnetic field generating means, the gradient magnetic field generating means and
One unit consisting of the probe and
To move the part to be imaged with the movement of the subject
Means for following, the center position of the static magnetic field of the unit
Position always coincides with the center position of the part of the subject to be imaged
It is characterized by making it. According to a second aspect of the present invention, there is provided the MRI apparatus according to the first aspect.
The unit supports the unit
It is linearly moved on the guide groove by the drive device.
I do. MRI equipment. [0012] A third aspect of the present invention is directed to the first or second aspect of the present invention.
In the MRI apparatus, the driving device and the guide groove are small.
At least two sets are installed, and the unit is
Sky of at least two dimensions due to combination of linear movement
It is characterized by moving between. The fourth invention is as described above.
An MRI apparatus according to any one of the first to third inventions
In the surface of the part of the subject to be imaged,
At least one marker is attached and the position of the marker
Is detected by a camera. [0015] A fifth aspect of the present invention is the first to third aspects of the present invention.
In the MRI apparatus according to any one of the inventions,
Calculates the change in position of the marker with the movement of
The driving amount of the driving device of the unit is determined based on the result.
It is characterized by that. According to the means of the present invention, the static magnetic field generation
Generating means, the gradient magnetic field generating means and the probe are one
A unit, wherein the unit is adapted to move the subject.
The unit follows the movement of the part to be imaged.
The center position of the static magnetic field
The heart positions can always be matched. [0015] This makes it possible to increase walking, jumping, bending and stretching.
The movement of the subject can be observed. Further, the surgical use of the MRI apparatus is expanded.
be able to. [0017] BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
This will be described in detail with reference to the drawings together with embodiments (examples).
You. Incidentally, an embodiment of the present invention will be described.
In all the drawings, those having the same functions are denoted by the same reference numerals.
Therefore, the description of the repetition is omitted. FIG. 1 shows an MR according to an embodiment (example) of the present invention.
FIG. 2 is a schematic diagram showing a schematic configuration of the I device, and FIG.
It is a schematic diagram which shows the schematic structure of a knit. 1 and 2
Here, 1 is a static magnetic field generating means, 2 is a gradient magnetic field generating means,
3 is a gradient power supply for driving the gradient magnetic field generating means, and 4 is high
A probe for receiving a high frequency magnetic field, 5 a high frequency transmitting / receiving unit, 6
Is a computer, 7 is a display, 8 is a subject, 9 is a unit, 1
Reference numeral 0 denotes a driving device, and reference numeral 11 denotes a unit guide rail. FIG. 1 shows an MRI apparatus according to this embodiment.
Thus, a static magnetic field generating means 1 for applying a static magnetic field to the subject 8,
A gradient magnetic field generating means 2 for applying a gradient magnetic field to the subject 8;
A gradient magnetic field power supply 3 for driving the gradient magnetic field generating means;
Irradiating a high-frequency magnetic field to the imaging region of
High-frequency magnetic field emitted by nuclear magnetic resonance
Probe 4 for receiving, static magnetic field generating means 1 and gradient magnetic field generation
Driving the generating means 2 and the probe 4 to irradiate the high-frequency magnetic field
High-frequency transmission / reception unit 5 for performing the reception and the gradient magnetic field power supply 3
Pulse sequence at the time of shooting by controlling the high-frequency transmitting and receiving unit 5
And the high-frequency signal received by the probe
A computer 6 for performing an image reconstruction operation using the computer 6;
Input the image signal generated in step 2 and display it as a tomographic image
The display 7 is constituted. Further, the static magnetic field generating means 1 and the gradient magnetic field generation
The means 2 and the probe 4 constitute a unit 9 (FIG. 2).
The unit 9 is driven by a drive unit 10 to guide the unit.
Linearly move on rails (hereinafter referred to as guide rails) 11
It is configured to move. The driving device 10 is a bed of an MRI device.
Hydraulic bed similar to that used to move the bed
Suitable for actuators, reciprocating hydraulic cylinders
Of the unit 9 in the Z direction by the combination of
Has achieved a linear motion. FIG. 3 shows details of the mechanism of the driving device 10.
You. The driving device 10 is shown in FIGS. 3 (a) and 3 (b).
The joints 50, 51, 52, 53, 54,
Link 55, 56, cylinder 57, hose 58, pump
59. Pump 59 to hose 58
, The cylinder 57 is driven. The cylinder
When the extension 57 is extended, as shown in FIG.
Since the point 53 rises on the guide rail 11, the
The unit 9 integrated with the point 53 rises. When the cylinder 57 contracts, FIG.
As shown in FIG.
Since it descends on the joint 11, it is integrated with the joint 53.
Unit 9 descends. The joints 50, 51, 52, 53,
54, links 55, 56, cylinder 57, hose 5
8. The driving mechanism constituted by the pump 59
Device 10 is generically referred to. Similarly, straight lines in the X, Y, and Z directions are used.
Hydraulic actuator and link mechanism that realize linear motion
As shown in FIG.
21, a driving device 22, and a driving device 23. here,
In the xyz coordinate system, the waist when the subject 8 bends and stretches
A case of tracking a change in a cross section will be described. FIG. 4 shows the cross section 30 of the subject 8 to be imaged.
(Body surface), at least one or more markers 31
It shows that you wear it. The position of the marker 31 is
Example 9 is read by the camera 32 installed near the
For example, time t₀Of the marker 31 at (mx₀,
my₀, Mz₀) Is obtained. Now, the subject 8 moves,
Time t₀The coordinates of the marker 31 are (mx₁, My₁, M
z₁), I want to shoot with marker 31
Since the positional relationship between the parts is fixed,
Movement amount (mx₁-Mx₀, My₁-My₀, Mz₁-M
z₀) Is the movement amount of the cross section, and the unit 9 also follows
Amount. Movement of the unit 9 shown in FIG. 5 in the X direction
Is moved by the drive device 21 on the guide rail 24.
The movement in the Y direction is performed by the drive device 22.
Movement on the id rail 25, and movement in the Z direction.
The movement corresponds to the movement on the guide rail 26 by the driving device 23.
This is done. The subject 8 emits an opposing static magnetic field from the unit 9.
It shall stand in the raw means 1. First, before bending and stretching,
Beforehand, take a cross section of the magnet at the center point,
A desired section (section of the region of interest) 30 is determined. The operator
In the unit 9 manually or by an instruction from the computer 6
The center position 27 is moved to a part to be photographed and an image is photographed. The center of the captured image is the center of the unit 9
(Center of the static magnetic field)
Good. The center of the static magnetic field (or the central region of the static magnetic field)
Points or areas where high uniformity and good image quality can be obtained
That is. The center of the image displayed on the display 7 or the image quality
Check that the target part is in a good part. At this time, eyes
The target part is located at the center of the static magnetic field as described above,
An image is obtained. However, if this is not the case (the target
In the case where it is not at the center of the magnetic field), the unit 9 is moved to
Repeat the process of capturing the image (ie, a good image
Until it is obtained). In FIG. 5, as described above, the photographed cross section
Is determined, the posture shown in FIG.
T is the start time₀And the coordinates (m
x₀, My₀, Mz₀) Is read by the camera 32
You. Next, the subject 8 starts bending and stretching, and at time t₁
At the position shown in FIG. 5B, and the coordinates of the marker
Is (mx₁, My₁, Mz₁).
The camera 32 adjusts the coordinates (mx₁, My₁, M
z₁) Is read, and the computer 6 calculates the amount of movement of the marker 31.
(Mx₁-Mx₀, My₁-My₀, Mz₁-Mz₀)
And drive devices 21, 22, and 23 are respectively set to mx₁-M
x₀, My₁-My₀, Mz₁-Mz₀Drive one by one
You. The link mechanism shown in FIG.
Mx the center position of dot 9₁Cylinder 57 for
Mx extruded length and the center position of unit 9₀When
The extruding length of the cylinder 57 for
The length of pushing cylinder 57 is determined by pump
Can be converted to quantity. Therefore, the movement mx₁-Mx
₀Is controlled by the computer 6 to control the pump drive.
Achieved. Also, my₁-My₀, Mz₁-Mz₀
Is achieved in a similar manner. As a result, unit 9
Is mx in the X, Y, and Z directions₁-Mx₀, My
₁-My₀, Mz₁-Mz₀Move one by one. Calculator 6
Is the second image under the same conditions as when the first image was taken.
Take an image. Time t₂In FIG. 5, the subject 8
(C), and the coordinates of the marker 31 are (mx
₂, My₂, Mz₂). Camera 3
2 is the coordinates (mx₂, My₂, Mz₂)
The computer 6 reads and moves the marker 31 (mx₂−
mx₁, My₂-My₁, Mz₂-Mz₁)
Drive devices 21, 22, and 23 are each mx₂-Mx₁, My
₂-My₁, Mz₂-Mz ₁Drive one by one. The result
As a result, the unit 9 is mx in each of the X direction, the Y direction, and the Z direction.₂
-Mx₁, My₂-My₁, Mz₂-Mz₁Move one by one
You. Calculator 6 uses the same conditions as the conditions under which the first image was taken.
Take a third image with the subject. As shown in FIG.₂Since then,
The posture of the sample 8 changes, and the
The same part can be obtained by repeating
Can be tracked. Here, the shooting time of the image is
Let T be the reading interval t of the position of the marker 31₁−
t₀And T <t₁-T₀Becomes That is,
The allowable range of the shadow time is between reading of the marker 31.
It is within the distance. EPI = (Echo Planar Imaging) method,
FISP (Fast Imaging with Steady Precesion)
Tens of milliseconds (msec) if high-speed imaging methods such as
Since an image can be captured in about 1 second (sec),
Is sufficiently achievable. In addition, reading of the marker 31
The sampling interval is equal (t₁-T₀= T₂-T₁)
It is also unequal intervals (t₁-T₀≠ t₂-T₁)
Is also possible. Further, the camera 32 recognizes the marker 31.
If not, the movement amount of the marker 31 (mx₂
-Mx₁, My₂-My₁, Mz₂-Mz₁), But set
If the movement limit per one time is exceeded,
The distance between the surface of the body 8 and the surface of the unit 9 is set.
It may be less than a certain interval or multiple
At least one of the conditions is an operation of the unit 9
By providing the function of stopping the
The safety of the I device is guaranteed. For example, the body surface
Use the distance sensor built into the unit to determine the distance on the surface
Can be detected. Contact between body surface and unit surface
Touch can be detected by using the built-in impact sensor in the unit.
Can be As described above, according to the present embodiment,
For example, walking, jumping, bending and stretching etc.
It is possible to image changes in the subject during exercise
You. As described above, the present invention is based on the present embodiment.
Although specifically described, the present invention is limited to the present embodiment.
It does not deviate from the gist of the
Of course, various changes can be made. [0041] According to the invention disclosed in the present application,
The effect obtained is briefly described as follows. According to the present invention, the center position of the static magnetic field of the unit
Position always coincides with the center position of the part of the subject to be imaged
Can be done. Thus, walking, jumping, bending and stretching, etc.
The movement of the subject can be observed. Further, the surgical use of the MRI apparatus is expanded.
be able to.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing a schematic configuration of an MRI apparatus according to an embodiment (example) of the present invention. FIG. 2 is a schematic diagram illustrating a schematic configuration of a unit according to the present embodiment. FIG. 3 is a schematic diagram showing details of a mechanism of the driving device according to the embodiment. FIG. 4 is a diagram illustrating a state in which a marker is attached near a section (body surface) of the subject to be imaged according to the present embodiment; FIG. 5 is a schematic diagram for explaining an operation of a mechanism of the driving device according to the embodiment. FIG. 6 is a schematic diagram showing a schematic configuration of a conventional MRI apparatus. [Description of Signs] 1 ... Static magnetic field generating means 2 ... Gradient magnetic field generating means 3 ... Gradient magnetic field power supply 4 ... Probe 5 ... High frequency transmitting / receiving unit 6 ... Computer 7 ... Display 8 ... Subject 9 ... Units 10, 21, 22,
23 ... Drivers 11, 25, 26 ... Guide rails 12 ... Bed 30 ... Cross section (cross section of region of interest) 31 ... Marker 32 ... Cameras 50, 51, 52,
53, 54 ... joint 55, 56 ... link 57 ... cylinder 58 ... hose 59 ... pump

Claims (1)

1. A static magnetic field generating means for applying a static magnetic field to an object, a gradient magnetic field generating means for applying a gradient magnetic field to the object, and a gradient magnetic field power supply for driving the gradient magnetic field generating means. ,
A probe that irradiates a high-frequency signal to a diagnostic site of the subject and receives a high-frequency signal emitted by nuclear magnetic resonance of a living tissue of the subject; and irradiates and receives the high-frequency signal by driving the probe. A high-frequency transmitting and receiving unit that performs the control of the gradient magnetic field power supply and the high-frequency transmitting and receiving unit according to a pulse sequence at the time of imaging and a computer that performs an image reconstruction operation using a high-frequency signal received by the probe, and a computer generated by the computer. A magnetic resonance imaging apparatus provided with a display for displaying the image obtained, a unit including the static magnetic field generating means, the gradient magnetic field generating means, and the probe, and the unit for moving the subject. Means for following the movement of the part to be imaged, and the center position of the static magnetic field of the unit and the part of the subject to be imaged. Magnetic resonance imaging apparatus characterized by always match the center position.