JPH0568977B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a magnetic resonance imaging apparatus capable of performing cine photography.

(Prior art) In recent years, magnetic resonance imaging devices (hereinafter referred to as
Cine imaging is performed on soft tissue such as knee joints using the characteristics of MRI equipment (referred to as MRI equipment).

Figures 4a and 4b show the subject (usually a patient)
FIG. 2 is a side view showing a conventional method for fixing a knee joint.

As shown in FIG. 4a, after placing the subject 1 on the top plate 2 of the bed and supporting the knee 1a with the knee support mat 3, fixing bands 4, 5, and 6 are used to prevent the subject 1 from moving. It is fixed with a removable fastener. The fixation band 4 is a band that fixes the torso 1b of the subject 1, the fixation band 5 is a band that fixes the knee 1a to the knee support mat 3, and the fixation band 6 is a band that fixes the heel 1.
This is a band that fixes c to the top plate 2. Further, the knee support mat 3 and the top plate 2 are fixed by detachable fasteners.

Then, the operator operates the MRI apparatus with the subject 1 in the posture shown in FIG.

Next, when the first photographing is completed, the operator removes the fixing band 6 fixing the heel 1c and places the heel support mat 7 under the knee 1c as shown in FIG.
, change the angle of the knee 1a, and fix the heel 1c to the heel support mat 7 with the fixing band 6. The heel receiving mat 7 and the top plate 2 are fixed by detachable fasteners.

Similarly, the operator operates the MRI apparatus with the subject 1 in the posture shown in FIG.

Here, if the operator wishes to further change the angle of the knee 1a and perform a third imaging with the knee 1a as the imaging site, the operator should move the heel support mat 7 in this manner in the same way as shown in Figure b. Change the height of Matsuto 7 to a different one and take a picture.

The photographed image thus obtained is reconstructed and displayed as a cine photograph to diagnose the knee.

(Problem to be Solved by the Invention) Since the conventional device is configured as described above, when performing cine imaging of the knee, the operator must check the subject's knee every time the MRI device performs cine imaging. The operator had to change the angle, which placed a burden on the operator.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a magnetic resonance imaging apparatus that can reduce the burden on the operator and efficiently obtain magnetic resonance images for each posture of the same imaging region of a subject.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the present invention provides a magnetic resonance imaging apparatus that obtains a plurality of magnetic resonance images of the same imaging region of a subject under sequence control. The apparatus is characterized by comprising a posture changing mechanism that changes the posture of the imaging region, and a control means that operates the posture changing mechanism in correspondence with each of the plurality of magnetic resonance images being taken, and In a magnetic resonance imaging apparatus that obtains a magnetic resonance image based on a magnetic resonance signal obtained from the subject by irradiating a high-frequency pulse to the subject placed in a static magnetic field, the posture of the subject is changed. The present invention is characterized in that it has a posture changing mechanism, and includes a control means for driving the posture changing mechanism and collecting magnetic resonance signals corresponding to the posture of the subject.

(Operation) According to the present invention having the above configuration, when the control means operates the posture changing mechanism in correspondence with each time a plurality of magnetic resonance images are taken, the posture of the imaged region of the subject is changed by the posture changing mechanism. Changes intermittently. Thereby, magnetic resonance images can be obtained for each posture of the same imaging region of the subject. Further, when the control means drives the posture changing mechanism, the posture of the subject changes. The control means then collects magnetic resonance signals corresponding to the posture of the subject. This results in
Magnetic resonance images can be obtained for each posture of the same imaging region of the subject.

(Example) FIG. 1 is an overall schematic configuration diagram of an MRI apparatus of the present invention.

1 is a subject placed on the top plate 2 of a bed 8;
The static magnetic field generating means 14 and the gradient magnetic field generating coil 1
3 and a coil 1 that irradiates high-frequency pulses to the subject 1.
15 is a coil for detecting magnetic resonance signals from the subject 1; 20 is the subject 1;
31 is a receiver 3;
2. A sequencer that sequentially controls the transmitter 33 and the gradient magnetic field power supply 34; 30 is a computer as a control means that controls the sequencer 31 and the attitude change mechanism 20 according to settings from the keyboard 35 and outputs the imaging results to the display 36; It is a system.

Figures 2a to 2c are detailed explanatory diagrams of the attitude changing mechanism 20, where figure a is a side view and figure b is a side view.
Figure c is a sectional view taken along line AA in Figure 1, and figure c is a BB sectional view in figure a.

21 is a support member that is a joint fixing mechanism for supporting the swing center P of the knee 1c, which is a joint, so that it does not move; 26 is a swing mechanism that moves part of the heel 1c of the subject 1 in the vertical direction. The pneumatic cylinder 27 is a pneumatic motor that is a swinging mechanism that drives the pneumatic cylinder 26.

The support member 21 is a member made of non-magnetic metal or resin and has a U-shaped cross section, and a knee support mat 22 for receiving the knee 1a is fixed to the U-shaped upper surface side of the support member 21. . Further, a slide portion 23 that slides within an inverted T-shaped groove 2a provided in the top plate 2 is fixed to the U-shaped lower surface side of the support member 21.

The pneumatic cylinder 26 includes a piston shaft 26b that moves up and down by air pressure from the pneumatic motor 27, a cylinder tube 26c, and an upper plate 26.
It is composed of a. In addition, this upper plate 26a
A heel receiving mat 25 for receiving the heel 1c is fixed to the upper surface side. A slide portion 26d that slides within an inverted T-shaped groove 2a provided in the top plate 2 is fixed to the lower surface side of the cylinder tube 26c.

The pneumatic motor 27 has a pipe 27a that transmits pneumatic pressure from the motor 27 in order to move the piston shaft 26b up and down based on an operation signal from the computer system 30 shown in FIG.
is provided between the motor 27 and the cylinder tube 26c.

Next, the operation of the apparatus of this embodiment configured as described above will be explained with reference to FIGS. 1 and 2, and FIG. 3 showing an explanation of a series of operations.

First, from the keyboard 35 shown in FIG. 1, the repetition time TR, the number of additions N, and the number of images M for irradiating the subject with a high-frequency pulse that excites magnetic resonance signals.
Enter the shooting conditions such as (step 1).

Next, the subject 1 is placed on the top plate 2 of the bed 8, the knee 1a is placed on the knee support mat 22, and the knee 1a is fixed with the fixing band 5, as shown in FIG. 2a. Then, the heel 1c is placed on the heel receiving mat 25 and the heel 1c is fixed with the fixing band 6. Further, the body portion 1b is also fixed with a fixing band 4. The support member 21 that supports the knee 1a and the pneumatic cylinder 26 that supports the heel 1c are manually slid into the inverted T-shaped groove 1a by sliding the respective sliding parts 23 and 26d into the inverted T-shaped groove 1a, or by manually operating the manual operation switch 27b of the pneumatic motor 27. By operation, the piston shaft 26b of the pneumatic cylinder 26 is driven in the D1 and D2 directions to set the initial angle of the knee 1a (step 2). by the way,
This pneumatic motor 27 has a one-touch detachable joint portion 27c, and a safety valve (not shown) for overload prevention is provided in the manual operation switch 27b.

Then, as shown in FIG. 1, the subject 1 is moved by sliding the top plate 2 into the opening 11 of the magnet mount 10. Next, when a start button (not shown) on the keyboard 35 is pressed, the computer system 30 sends a signal S0 to the sequencer 31, and the sequencer 31 controls the irradiation timing of high-frequency pulses, the gradient magnetic field by the gradient magnetic field power supply 34, etc. . A high-frequency pulse is irradiated from the coil 12 to the subject 1 placed in a static magnetic field by the static magnetic field generating means 14 based on the high-frequency applied voltage from the transmitter 33, thereby causing a magnetic resonance phenomenon within the subject 1. At the same time, in order to obtain positional information of the magnetic resonance signal induced site, power is transmitted from the gradient magnetic field power source 34 to the gradient magnetic field coil 13 to generate a gradient magnetic field, and the magnetic resonance signal induced in the subject 1 is transmitted to the gradient magnetic field coil 13. To detect. The signal detected by this coil 15 is transmitted to the receiver 3
2 and transmitted to computer system 30 for data collection. The operation from irradiating these high-frequency pulses to transmitting them to the computer system 30 is repeated N times, which is the number of additions set on the keyboard 35 (step 3).

The computer system 30 compares the set number of shots M with the finished number of shots (step 4).

If data collection for the number of photographed images M has not been completed, the computer system 30 transmits an operation signal S2 to the posture changing mechanism 20 based on a completion signal S1 from the sequencer 31. Based on this operation signal S2, a predetermined air pressure is applied to the pneumatic cylinder 26 from the pneumatic motor 27 of the attitude change mechanism 20.
, the piston shaft 26b rises in the direction of the arrow D1, and the heel 1c swings in the direction of the arrow C about the swing center P by a change angle corresponding to the predetermined stroke S. The support member 21 supporting the knee 1a is assembled in the direction indicated by the arrow E by turning the fixing screw 24 having a male threaded portion 24a that is screwed into the female threaded portion 23b of the slide portion 23.
1. Movement in two directions of EE is restricted. Also knee 1
Since a is fixed to this support member 21 by the fixing band 5, it does not move in any direction. When the piston shaft 26b rises in the direction of arrow D1, the heel 1c is attached to the piston shaft 2 by the fixing band 6.
Since the pneumatic cylinder 26 is fixed to the side,
It is pushed in the direction of arrow E2 and moves (step 5).

After the time period of the swinging operation (ⓓⓓ minutes) by the posture changing mechanism 20 has elapsed, the computer system 30 transmits a signal S0 to the sequencer 31 to cause the sequencer 31 to perform the same operation as described above (step 6).

Next, the computer system 30 compares the set number of shots M with the finished number of shots (step 7).

Here, if the number of photographed images M is 3, data collection has been completed for only two of the number of photographed images, so the computer system 30 again sends the operation signal S2 to the attitude change mechanism 20 (step 5). )
Similarly, a swinging motion of 〓〓 corresponding to the predetermined stroke 〓S is performed.

Subsequently, the computer system 30 transmits a signal S0 to the sequencer 31 after the time period of the swinging operation (〓〓 minutes) by the posture changing mechanism 20 has elapsed, and the computer system 30 transmits the signal S0 to the sequencer 31 to cause the sequencer 31 to perform the same operation as described above (step 4). , (step 5). The computer system 30 compares the set number of shots M and the finished number of shots in the same way as in (step 4). (step 7).

Here, when the number of images taken M times is completed, the M images obtained by averaging the data of N times are reconstructed (step 8).

Then, it is displayed on the display 36 as a cine image (step 9).

This completes the series of operations performed multiple times in this embodiment.

Since the device of this embodiment is configured in this way, the operator only needs to input the imaging conditions shown in Fig. 3 (step 1), fix the subject and set the knee angle (step 2). This allows cine imaging of the knee to be performed, reducing the burden on the operator.

Further, since the knee 1a is securely fixed by the fixing band 5 or the like, a good image can be obtained.

Although one embodiment has been described above, the present invention is not limited to this, and various modifications can be made without changing the gist thereof.

For example, although the swinging mechanism of the attitude changing mechanism 20 is configured with a pneumatic cylinder 26 that moves up and down, E
It may be a mechanism that drives the 1 and E2 directions and the D1 and D2 directions separately. Furthermore, the motion load can be reduced by moving the joints while constantly controlling the joint positions and collecting data synchronized with the positions. It is also possible to take time cine shots.

Furthermore, cine imaging can be performed on joints other than the knee, such as the elbow.

[Effects of the Invention] According to the present invention described in detail above, there is no need for the operator to change the posture of the imaging site of the subject each time a magnetic resonance image is taken, so the burden on the operator is reduced. It is possible to provide a magnetic resonance imaging apparatus that can efficiently obtain magnetic resonance images for each posture of the same imaging region of a subject.

[Brief explanation of the drawing]

1 to 3 are views of an apparatus according to an embodiment of the present invention, in which FIG. 1 is a schematic configuration diagram of the apparatus, and FIGS. 2a to 2c are detailed views of the attitude changing mechanism shown in FIG. 1. , FIG. 2a is a longitudinal cross-sectional view, and FIG. 2b is a line taken along A-A in FIG. 2a.
2c is a sectional view taken along line BB in FIG. 2a, FIG. 3 is a flowchart for explaining the operation of the device in FIG. 1, and FIGS. FIG. 3 is an explanatory diagram showing a method of fixing a human leg. 1... Subject, 12, 15... Coil, 14...
... Static magnetic field generating means, 20 ... Posture change mechanism, 30
...Computer system (control means).

Claims (1)

[Scope of Claims] 1. A magnetic resonance imaging apparatus that obtains a plurality of magnetic resonance images of the same imaging region of a subject under sequence control, comprising: a posture changing mechanism that changes the orientation of the imaging region; A magnetic resonance imaging apparatus comprising: a control means for operating the attitude changing mechanism in correspondence with each time an image is taken. 2. In a magnetic resonance imaging apparatus that obtains a magnetic resonance image based on a magnetic resonance signal obtained from the subject by irradiating a high-frequency pulse to the subject placed in a static magnetic field, changing the posture of the subject. 1. A magnetic resonance imaging apparatus, comprising: a posture changing mechanism; and a control means for driving the posture changing mechanism to collect magnetic resonance signals corresponding to the posture of the subject. 3. The posture changing mechanism includes a joint fixing mechanism that swingably fixes the joints of the subject, and a rocking mechanism that holds and swings a part of the subject around the joints fixed by the joint fixing mechanism. 3. The magnetic resonance imaging apparatus according to claim 1, further comprising a moving mechanism.