JP3135136B2 - Magnetic resonance imaging equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic resonance imaging apparatus for obtaining a tomographic image of a desired portion of a subject by utilizing a magnetic resonance phenomenon, and more particularly to an improvement of a bed having a headrest provided with a high-frequency receiving coil. Things.

[0002]

2. Description of the Related Art In a conventional magnetic resonance imaging apparatus, a gradient magnetic field generating coil and a transmitting high frequency coil are provided in a gantry constituting a static magnetic field generating apparatus. The bed used in the magnetic resonance imaging apparatus has a table on which a subject is placed, and a headrest is provided at the tip of the table. The headrest supports the head of the subject and is provided with a receiving high-frequency coil. The receiving high-frequency coil applies a uniform static magnetic field to the subject in the gantry, and generates a magnetic resonance generated from the subject when an electromagnetic wave having a frequency for exciting magnetic resonance is applied to the subject by the transmitting high-frequency coil. A ring is formed to receive the signal and to cover the head of the subject to be examined.

[0003] At that time, in order to specify a magnetic resonance signal from the subject at the time of examination, a gradient magnetic field is applied in an appropriate direction by the gradient magnetic field coil, and a cross section at an arbitrary angle of the examination site is obtained by the direction of the gradient magnetic field. Like that. Therefore, the headrest is generally fixed to the tip of the table in parallel with the horizontal plane.

[0004]

In the above-mentioned prior art, no consideration was given to the case where a subject having an obstacle at the time of examination as well as a subject having a physical disorder is photographed. For example, when imaging a subject whose neck is not bent or a subject whose back is bent,
In the prior art, when a subject is laid on a bed and its head is supported by a head support in a state parallel to a horizontal plane, the jaw of the head is moved up and down. For this reason, as described above, since the receiving high-frequency coil is fixed to the head support in a horizontal plane, it may not be possible to take a picture as it is.

Therefore, the receiving high-frequency coil is replaced with a large-diameter receiving high-frequency coil so that the jaw of the subject cannot be held. However, if a large-diameter receiving high-frequency coil is used, a gap is generated between the coil and the inspection part of the head, and thus there is a problem that the S / N ratio as a tomographic image is reduced. In order to improve the S / N ratio, it is preferable that the imaging site and the receiving high-frequency coil be closely adhered to each other. However, even if there is a gap, the imaging is currently forced.

In addition, the subject has to take a posture in accordance with the head support, and if the subject is photographed in an unreasonable posture, it will be painful. For this reason, there is a problem in that if the camera is taken in an unreasonable posture, the camera moves during the shooting, and motion artifacts occur.

An object of the present invention is to provide a magnetic resonance imaging apparatus capable of taking an image of a subject with a disability without being distressed and taking an unreasonable posture in view of the above-mentioned problems of the prior art. Is to provide.

[0008]

To achieve the above object, according to the solution to ## and the static magnetic field generating means for applying a static magnetic field to the subject, a gradient magnetic field generating means for applying a gradient magnetic field to said subject, prior Symbol subject biological comprising a transmission high-frequency coil for irradiating a high frequency to excite magnetic resonance in atomic nuclei of atoms constituting tissues, the received high-frequency coil for detecting the echo signal emitted by a magnetic resonance before <br/> Symbol has Atama受, in the magnetic resonance imaging apparatus and a bed that can Neno pre Symbol subject, the Atama受includes a head receiving portion for holding the head of the subject, up and down the head receiving portion A supporting portion that is movably supported in the direction and is fixed to the bed. The supporting portion further includes a base fixed to the bed and a guide that guides the head receiving portion to be movable in the vertical direction. Hole and the head inserted through the guide hole A fixing screw for fixing by tightening the parts and the support part, in which more configured with movement assist mechanism for applying a force always pushes direction the head receiving portion. Further, the headrest is a support part fixed to the bed, a head reception part arranged on the support part to hold the head of the subject, and a movement adjusting screw for moving the head reception part in a vertical direction. And the support portion further includes a guide hole for guiding the head receiving portion movably only in the vertical direction,
The head receiving portion includes a guide pin that fits into the guide hole and restricts movement in a direction other than the vertical direction. The movement adjusting screw is screwed into the head receiving portion and a lower screw that is screwed into the support portion. Upper screw, and a knob for connecting and rotating the lower screw and the upper screw, or fixed to the head support portion and the bed by a plurality of fixing screws for holding the head of the subject. And a spacer that is sandwiched between the bed and the support portion, and the spacer includes a notch for inserting and removing the support portion from a predetermined direction on the side of the support portion. Good.

[0009]

According to the present invention, the head support of the couch can be moved in the vertical direction by the moving means. Therefore, in the case of a subject whose neck is not bent or a subject whose back is bent, etc. The headrest can be appropriately adjusted to a desired position according to the posture of the subject. Therefore, the jaw of the subject does not stick to the receiving high-frequency coil, and it is not necessary to replace the receiving high-frequency coil with a large-diameter receiving high-frequency coil. In addition, since a large-diameter receiving high-frequency coil is not used, the receiving high-frequency coil provided in advance on the bed can be brought into close contact with the subject, and no gap is generated. S /
In addition to preventing a decrease in the N ratio, the subject can be supported on the head support in a stable state, so that the subject does not move at the time of imaging, and the occurrence of motion artifacts can be prevented.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a cutaway perspective view of a main part of a bed showing a magnetic resonance imaging apparatus according to a first embodiment of the present invention, FIG. 2 is a perspective view of a headrest, FIG. 3 is a side view of the headrest, and FIG. 5 is a perspective view for explaining the magnetic resonance imaging apparatus.

In FIG. 5, 1 is a static magnetic field generator, 2 is a bed, 3 is an MRI unit, 4 is a central processing unit, and 5 is a multi-format camera. Although not shown in detail, the static magnetic field generating device 1 includes a static magnetic field generating magnet for generating a uniform static magnetic field, a gradient coil provided in an internal space thereof for generating a gradient magnetic field, A transmission high-frequency coil provided inside the gradient coil to irradiate a high frequency for exciting magnetic resonance to the subject.

The couch 2 is for placing a subject on the couch, and has a head support 7 at a distal end of a table 6 above the couch. The head support 7 supports the head of the subject,
As shown in FIGS. 1 and 5, the receiving high-frequency coil 8 is provided so as to be movable parallel to a horizontal plane by a guide portion. The receiving high-frequency coil 8 is for receiving a magnetic resonance signal from the subject at the time of imaging, and has a ring shape. As shown in FIG. 1, the guide portion is fixed to the rear face of the head support 7 so as to extend in a substantially horizontal direction, and is fixed to the receiving high-frequency coil 8 and is adapted to both sides of the guide rail 71. The receiving high-frequency coil 8 is moved in the horizontal direction as indicated by the arrow, that is, in the body axis direction by moving the guide rail 81 along the guide rail 71.
The MRI unit 3 houses a high-frequency power supply for applying a high-frequency pulse to the high-frequency transmission coil, a power supply for the gradient coil, and the like. The central processing unit 4 houses an image processing unit and a sequencer inside. The multi-format camera 5 captures an MR image on a film.

In this magnetic resonance imaging apparatus, a table 6 above a bed 2 on which a subject rests is moved into the static magnetic field generating device 1, so that the subject is uniformly statically moved by a static magnetic field generating magnet. When a magnetic field is applied and a high-frequency pulse amplified by a high-frequency amplifier in the MRI unit 3 is applied to a high-frequency transmitting coil in the static magnetic field generating device 1, an electromagnetic wave for exciting a magnetic resonance signal to the subject from the high-frequency transmitting coil is generated. Irradiated. After a certain time after the irradiation, the receiving high-frequency coil 8 detects a magnetic resonance signal from the subject, amplifies the detected signal with an amplifier in the MRI unit 3, detects the signal, and then detects the digital signal with an A / D converter. And sent to the image processing unit of the central processing unit 4. The image processing unit performs processing such as Fourier transform to reconstruct an image. that time,
The multi-format camera 5 transfers the reconstructed image to a film.

In this embodiment, the bed 2
Has a means capable of vertically moving the headrest 7 in parallel. The moving means is composed of a head support 7 and a support portion 10 as shown in FIGS. 2, 3 and 4, and the head support 7 includes a piston support portion 11, and the support portion 10 includes a piston mechanism portion. 12
And a guide portion 13. Specifically, head support 7
The moving shaft 14 having a rectangular shape is formed so as to be fitted to the base of the head support 7, and the end 14a protrudes from both ends of the base of the head support 7. The ends 14a are supported by the guide portions 13, 13, respectively. As shown in FIG. 4, the guide portion 13 has a vertically long insertion hole 15 for inserting the end portion 14 a of the moving shaft 14. The piston mechanism 12
Is composed of a cylinder portion 17 and a piston portion 18, and a constant pressure (about the average weight of the adult head / 2) is always applied to the inside of the cylinder, thereby reducing the moving force required for vertical translation. . On the other hand, the tip of the fixing screw 16 is screwed into the head support 7 through the elongated hole 15 of the guide portion 13.
When the head support 7 is translated in the vertical direction in the loosened state, the fixing screw 16 follows the guide portion 1
By moving the inside of the long hole 15 and tightening the head support 7 to the guide portion 13, the head support 7 can be fixed at a desired position in the vertical direction. Therefore, screw holes (not shown) for screwing the fixing screws 16 are provided on both end surfaces of the moving shaft 14 at the base of the head support 7. The guide section 13 is attached to the support section 10 by screws or the like, and the support section 10 is attached to the table 6 as shown in FIG.

In the magnetic resonance imaging apparatus configured as described above, the subject is laid on the bed 2 at the time of examination.
At this time, in the case of a subject whose neck is not bent or a subject whose back is bent, the horizontal position of the headrest 7 is changed by the moving means according to the body shape of the subject. That is, when the fixing screw 16 is loosened, the head support 7 rises upward due to the pressure in the cylinder. Then, the head is mounted on the head support 7 and the fixing screw 16 is tightened at a desired position to fix the head support 7. Thus, the head of the subject can be supported and fixed to the head support 7 in a stable state, and the positioning can be easily performed.

In this way, by moving the head support 7 in parallel in the vertical direction, it is possible to appropriately adjust the head support 7 according to the body shape of the subject. Therefore, it is not necessary to replace the receiving high-frequency coil 8 with a large diameter. Moreover, since the receiving high-frequency coil 8 having a large diameter is not used, there is no gap between the receiving high-frequency coil 8 provided in advance on the bed 2 and the subject. S / N of fault increase
Not only can the ratio be prevented from being reduced, but also the subject can be prevented from moving during imaging and motion artifacts can be prevented.

FIGS. 6, 7 and 8 show another embodiment of the magnetic resonance imaging apparatus of the present invention. The moving means in this case is, as shown in FIG.
Numeral 0 is integrally formed via a translation adjustment screw 21, and the head support 7 a is provided with a screw hole 22 and a translation pin 23 for inserting the translation adjustment screw 21. A screw hole 24 for inserting the translational adjustment screw 21 and a guide hole 25 for parallel translation are provided.

The translation adjustment screw 21 is used to adjust the amount of translation when the translation is performed in the vertical direction.
It has a threaded portion above and below a. The screw part has a headrest 7
If the side to be inserted into a is a right-hand thread, the side to be inserted into the support part 20 is a left-hand thread. That is, when the knob 21a is turned in one direction, the head support 7a and the support 20 move in opposite directions. The parallel movement pin 23 is provided to prevent the head support 7a from rotating in the same direction as the direction in which the knob 21a is turned when the knob 21a is turned and translated in parallel, and is provided on the head support 7a side. ing. The parallel movement guide hole 25 is a hole for guiding the parallel movement pin 23, and is provided in the support portion 20. The support 2
0 is attached to the table 6 as shown in FIG.

According to this embodiment, since the head support 7a can be moved in parallel in the vertical direction, basically the same operation and effect as those of the first embodiment can be obtained.

FIGS. 9 and 10 show another embodiment of the magnetic resonance imaging apparatus according to the present invention. The movement adjustment method in this case is such that a spacer 30 as shown in FIG. 10 is placed under the head support 7b and positioned at a desired position in the vertical direction. Note that several types of spacers 30 having different thicknesses t are prepared. Since the head support 7b is attached to the table 6 with the fixing screw 31, the notch 32 is provided in the spacer 30, so that the head support 7b can be easily moved. According to this embodiment, the structure of the moving means can be simplified as compared with the first and second embodiments.

[0021]

As described above, according to the present invention, the head support of the couch is horizontally moved in the vertical direction by the moving means, and the subject whose neck is not bent or whose back is bent is used as the subject. In the case of the examiner, etc., since the head support can be appropriately adjusted to a desired position according to the posture of the subject, the jaw of the subject does not stick to the high-frequency coil for reception. It is no longer necessary to replace the receiving high-frequency coil with a diameter, and the receiving high-frequency coil can be brought into close contact with the subject, so that the S / N ratio of the tomographic image when the image is reconstructed decreases. This has the effect of preventing motion artifacts as well as preventing the occurrence of motion artifacts.

[Brief description of the drawings]

FIG. 1 is a cutaway perspective view of a main part of a bed showing a first embodiment of a magnetic resonance imaging apparatus.

FIG. 2 is a perspective view of a head support.

FIG. 3 is a side view of a headrest.

FIG. 4 is a local sectional view taken along line AA of FIG. 2;

FIG. 5 is an explanatory perspective view showing a magnetic resonance imaging apparatus.

FIG. 6 is a perspective view of a head support showing a second embodiment of the magnetic resonance imaging apparatus.

FIG. 7 is a local sectional view taken along line BB of FIG. 6;

FIG. 8 is a local sectional view taken along line CC of FIG. 6;

FIG. 9 is a perspective view of a head support showing a third embodiment of the magnetic resonance imaging apparatus.

FIG. 10 is a perspective view of a spacer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Static-magnetic-field generator 2 Bed 6 Table 7 Head support 7a Head support 7b Head support 8 High-frequency coil for reception 10-18 Moving means 20-25 Moving means 30-32 Moving means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A61B 5/055

Claims (3)

(57) [Claims] 1. A static magnetic field generating means for applying a static magnetic field to a subject, a gradient magnetic field generating means for applying a gradient magnetic field to the subject,
A transmission high-frequency coil for irradiating a high frequency to excite magnetic resonance in atomic nuclei of atoms constituting the living tissues of the previous SL subject, a receiving high-frequency coil for detecting the echo signal emitted by a magnetic resonance before Symbol has Atama受with the magnetic resonance imaging apparatus and a bed that can Neno pre Symbol subject, the Atama受includes a head receiving portion for holding the head of the subject, the head
The receiving part is supported movably in the vertical direction, and is fixed to the bed.
And a supporting portion, wherein the supporting portion is
Move the base fixed to the bed and the head support vertically.
A guide hole movably guided, and inserted through the guide hole.
A fixing screw for tightening and fixing the head receiving portion and the support portion
And a force that applies force in the direction that always pushes up the head support.
A magnetic resonance imaging apparatus comprising a motion assist mechanism . 2. A static magnetic field generating means for applying a static magnetic field to a subject, a gradient magnetic field generating means for applying a gradient magnetic field to the subject,
A transmission high-frequency coil for irradiating a high frequency to excite magnetic resonance in atomic nuclei of atoms constituting the living tissues of the previous SL subject, a receiving high-frequency coil for detecting the echo signal emitted by a magnetic resonance before Symbol has Atama受with the magnetic resonance imaging apparatus and a bed that can Neno pre Symbol subject, the Atama受includes a supporting portion for fixing said bed, it is disposed above the support portion A head receiving unit for holding the head of the subject,
A moving adjustment screw for moving the head receiving portion in the vertical direction, the support portion further includes a guide hole for guiding the head receiving portion movably only in the vertical direction, and the head receiving portion is A guide pin that fits into a guide hole and restricts movement in a direction other than the vertical direction, wherein the movement adjustment screw is a lower screw screwed to the support portion; an upper screw screwed to the head receiving portion; A magnetic resonance imaging apparatus comprising a knob for coupling and rotating a lower screw and an upper screw. 3. A static magnetic field generating means for applying a static magnetic field to a subject, a gradient magnetic field generating means for applying a gradient magnetic field to the subject,
A transmission high-frequency coil for irradiating a high frequency to excite magnetic resonance in atomic nuclei of atoms constituting the living tissues of the previous SL subject, a receiving high-frequency coil for detecting the echo signal emitted by a magnetic resonance before Symbol has Atama受with the magnetic resonance imaging apparatus and a bed that can Neno pre Symbol subject, the Atama受includes a plurality the said bed and head receiving portion for holding the head of the subject A support portion fixed by a fixing screw is integrally formed, and a spacer is provided between the bed and the support portion. The spacer has a notch for inserting and removing the support portion from a predetermined direction on a side of the support portion. A magnetic resonance imaging apparatus comprising: