JPH055496B2 - - Google Patents

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention is directed to magnetic resonance (MR).
Regarding magnetic resonance diagnostic equipment that uses the phenomenon of morphological information such as slice images of a subject (living body) and functional information such as spectroscopy, it is particularly applicable to diagnosis not only in the recumbent position but also in various body positions. The present invention relates to a magnetic resonance diagnostic device that enables this.

(Prior art) Magnetic resonance phenomenon is a phenomenon in which an atomic nucleus with an unusual spin and magnetic moment placed in a static magnetic field resonantly absorbs and emits only electromagnetic waves of a specific frequency. It resonates at the angular frequency ω ₀ (ω ₀ =2πν ₀ , ν ₀ ; Larmora frequency) shown in .

ω ₀ =γB ₀ Here, γ is the gyromagnetic ratio specific to the type of atomic nucleus, and B ₀ is the static magnetic field strength.

The device that performs biological diagnosis using the above principles is
The electromagnetic waves of the same frequency as above that are induced after the above-mentioned resonance absorption are signal-processed to produce diagnostic information that reflects information such as nuclear density, longitudinal relaxation time T1, transverse relaxation time T2, flow, chemical shift, etc. We are trying to obtain human slices non-invasively.

The collection of diagnostic information by magnetic resonance is able to excite all parts of the subject placed in a static magnetic field and collect signals, but there are limitations in the equipment configuration and clinical aspects of imaging. From the request,
The actual device excites a specific region and collects its signals.

In this case, the specific region to be imaged is generally a slice region with a certain thickness, and magnetic resonance signals (MR signals) such as echo signals and FID signals from this slice region are collected many times. The data is collected by performing a data encoding process, and an image of the specific slice region is generated by subjecting these data groups to image reconstruction processing using, for example, a two-dimensional Fourier transform method.

For example, Fig. 4 shows the configuration of an apparatus using a static magnetic field generating magnet 1 with the magnetic field direction of the static magnetic field B ₀ in the horizontal direction (transverse magnetic field system), and Fig. 5 shows the configuration of an apparatus in which the magnetic field direction of the static magnetic field B ₀ is horizontal (transverse magnetic field system). Magnetic field direction perpendicular (vertical magnetic field method)
This figure shows the configuration of a device using a static magnetic field generating magnet 2, each of which is composed of an electromagnet or a permanent magnet.

Generally, in the magnet 1 shown in FIG. 4, a superconducting coil or a normal conducting coil is arranged in a cylinder having openings at both ends in the horizontal direction, and an inner cylindrical space connected to the openings is used as an examination subject introduction space. Further, the magnet 2 shown in FIG. 5 has magnetic poles of unit coils or permanent magnets facing each other at a distance in the vertical direction, and this facing space is used as the subject introduction space.

In both methods, a bed 3 having a sliding top plate is installed close to the magnet 12, and the subject P is placed on the sliding top plate of this bed 3.
is inserted into the subject introduction space formed in the horizontal direction. Therefore, in the method shown in FIG. 4, the direction of the body axis of the subject P and the direction of the magnetic field are approximately the same, and in the method shown in FIG. is approximately a right angle.

Furthermore, according to the principle of magnetic resonance, it is a condition that the static magnetic field B ₀ and the excitation high-frequency magnetic field B ₁ be orthogonal to each other, so saddle-shaped coils 4 and 6 shown in FIG. Surface coil 5 shown in Figure b, solenoid coil 6 shown in Figure 6c
is limited in its application. That is, the fourth
In the horizontal magnetic field method shown in the figure, the saddle-shaped coil 4 shown in Fig. 6a and the surface coil 5 shown in Fig. 6b can be used.
The solenoid coil 6 shown in Figure c cannot be used.

In addition, in the vertical magnetic field method shown in Fig. 5, Fig. 6 c
Although the solenoid coil 6 shown in Fig. 6 can be used, it is also possible to use the saddle-shaped coil 4 shown in Fig. 6a, which has high versatility for diagnosis parts, and the surface coil 5 shown in Fig. 6b, which is suitable for diagnosis of local parts. Can not.

Furthermore, considering the required installation space for the device, in either method, the magnets 1 and 2 and the bed 3
Since these devices are installed in parallel, the horizontal direction of the device is approximately 5 meters, which, combined with the heavy weight of this type of device, makes installation conditions difficult.

In addition, in both of the above methods, the subject P is attached to magnets 1 and 2.
The subject is in a recumbent position within the introduction cavity, and as a result, diagnosis can only be made in the recumbent position, which may be problematic depending on the diagnosis content. For example, the spinal cord and vertebrae are subjected to excessive stress during normal living conditions, that is, when standing. Therefore, for a patient with a spinal hernia (subject P) for whom this stress is a factor, image diagnosis under this stress state is essentially required. However, since both of the above methods perform image diagnosis only when the subject P is in the recumbent position, it is not possible to perform image diagnosis in the stress state described above.

(Problems to be Solved by the Invention) As described above, in the conventional transverse magnetic field type or vertical magnetic field type devices, various transmitting and receiving coils cannot be used as desired, and the installation conditions are strict. Furthermore, there were other problems such as the inability to perform diagnosis in various body positions.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a magnetic resonance diagnostic apparatus that can use various types of transmitting and receiving coils as desired, eases installation conditions, and allows diagnosis in various body positions.

[Structure of the Invention] (Means for Solving the Problems) The present invention has a structure in which the following means are taken to solve the above problems and achieve the objects.
That is, the present invention includes a static magnetic field magnet having horizontally opposed magnetic poles, a gradient magnetic field coil, a transmitter/receiver coil, and an erected bed arranged in opposing spaces, and the erected bed is arranged so that the left and right directions of the subject are static. The subject is placed on an upright bed during a static magnetic field in an opposing space generated by a static magnetic field coil, which is arranged to rotate around an axis that coincides with the direction of the magnetic field and coincides with the direction of the static magnetic field. A gradient magnetic field is applied to the subject by a gradient magnetic field coil, and a high-frequency magnetic field for excitation is applied by a transmitter/receiver coil to produce a magnetic resonance phenomenon in a specific part of the subject. It is characterized in that it is configured to image at least one of morphological information and functional information of a specific region by collecting magnetic resonance signals using a transmitting/receiving coil and subjecting them to signal processing.

(Function) According to such a configuration, a static magnetic field is generated in the space facing the static magnetic field magnet, and in the facing space, a patient can be placed in various body positions on a reclining bed for diagnosis. can. In this case, since the raising/lowering bed can be installed in the opposing space, the required installation space is smaller than in the case of the horizontal magnetic field method or the vertical magnetic field method, and the installation conditions are relaxed. In addition, since the direction of the static magnetic field is perpendicular to the subject's body axis,
Various transmitting and receiving coils such as saddle coils, surface coils, solenoid coils, etc. can be used as desired.

(Embodiment) An embodiment of the magnetic resonance diagnostic apparatus according to the present invention will be described below with reference to FIG.

As shown in FIG. 1, the static magnetic field magnet 11 has a yoke portion 11a placed on the floor side and a main yoke portion 11a.
Leg portions 11b1 and 11b2 extend upward from both ends of a. And these leg parts 11b1, 11b
At the end of 2, there are magnetic poles 11c1, which face each other in the horizontal direction.
11c2. With this configuration, a static magnetic field B ₀ for generating magnetic resonance is generated between the magnetic poles 11c1 and 11c2 with the magnetic field direction horizontal. In this case, a shim coil (not shown) may be provided to correct the uniformity of the static magnetic field.

Further, gradient magnetic field coils 12 are provided on the surfaces of the magnetic poles 11c1 and 11c2, respectively. Further, in the space facing the magnetic poles 11c1 and 11c2, various transmitting and receiving coils such as a saddle-shaped coil, a surface coil, and a solenoid coil are provided (not shown).

On the other hand, an upright bed 13 is installed on the yoke portion 11a of the static magnetic field magnet 11, and a subject (not shown) can be placed on the top plate 13a of this upright bed 13. This top plate 13a consists of a footrest 13a1 and a body rest 13a2. Thereby, the magnetic field direction of the static magnetic field and the subject's body axis direction become perpendicular.

In addition to the above main body configuration, the gradient magnetic field coil 12
A gradient magnetic field power supply 14 is provided to drive the transmitter/receiver coil, and a transmitter/receiver 15 is provided to drive the transmitter/receiver coil. This gradient magnetic field power supply 14 and transmitter/receiver 15 are controlled by a sequencer 16, and this sequencer 1
6 is a computer system 1 including a reconfiguration processing system.
It is now under the control of 7.

Further, the image generated by the computer system 17 is displayed on the monitor 18, and the computer system 17 controls the bed control section 19, which controls the raising and lowering of the bed 13. It's getting old.

Next, the operation of this embodiment configured as described above is as follows.
This will be explained with reference to FIG. 1 and FIG. 2 which shows the operation of the upright bed 13. First, computer system 1
7 and the bed control unit 19, as shown in FIG.
Place your feet on 3a1 and place your torso on body rest 13a2
Stand in a natural position by leaning against it. Next, in order to set the desired part of the subject in the optimum magnetic field space or to obtain the desired body position, the top plate 13a is tilted to be in a tilted state (FIG. 2b) or in a horizontal state (FIG. 2c). Set it like this.

Here, for example, a surface coil (not shown) is placed at a desired site of the subject as a transmitting/receiving coil, and a command to execute an appropriate pulse sequence is given to the sequencer 16 from the computer system 17, and the sequencer 16 uses the gradient magnetic field power supply 14 and Transmitter/receiver 1
5, and the gradient magnetic field coil 12 and the transmitting/receiving coil are driven by the pulse power related to the pulse sequence.

As a result of the above, a specific region of the subject is excited by magnetic resonance, and then the induced magnetic resonance signals are collected by a transmitter/receiver coil and taken into the computer system 17 via the transmitter/receiver 15, and are reconstructed into, for example, a slice image. etc., and monitor 18
to be displayed.

As described above, according to this embodiment, the static magnetic field magnet 1
A static magnetic field is generated in the opposing space 1, and a test subject can be placed in various positions in the opposing space using an upright bed 13 for diagnosis. Therefore, image diagnosis can be performed not only when the subject is in a lying position but also in a stressed state, such as in a standing position.

Furthermore, since the raising/lowering bed 13 is installed in the opposing space, the required installation space is smaller than in the case of the horizontal magnetic field method or the vertical magnetic field method, and the installation conditions are relaxed.

Furthermore, since the direction of the static magnetic field is perpendicular to the subject's body axis, various types of transmitting/receiving coils such as saddle-shaped coils, surface coils, solenoid coils, etc. can be used as desired.

In addition, in the configurations shown in FIGS. 4 and 5, the subject perceives a feeling of being confined in a narrow space within the magnets 1 and 2, but in this embodiment, the subject feels trapped in a narrow space within the magnets 1 and 2. Upper or magnetic pole 11c1,1
Since the upper part of the opposing space of 1c2 is open,
The subject on the upright bed 13 perceives a feeling of openness,
Be in a psychologically favorable situation. It is particularly suitable for subjects who tend to have claustrophobia.

The present invention is not limited to the above embodiments. For example, if the raising/lowering bed 13 is provided with a lifting mechanism, the required movable range of the raising/lowering bed 13 can be reduced, making the installation conditions more suitable. Regarding the static magnetic field magnet, as shown in FIG. 3, the magnetic yoke 2 of the U-shaped iron core 20
A magnetic pole portion 20b1 extending upward from both ends of 0a,
The conductor 21 may be wound around the conductor 20b2 to constitute an electromagnetic static field magnet.

In the above case, the conductor 21 can be either a normal conducting wire or a superconducting wire. Furthermore, a mechanism for fixing the transmitting and receiving coils may be attached to the top plate 13 of the upright bed 13. In addition, various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] As described above, the present invention includes a static magnetic field magnet having horizontally opposed magnetic poles, a gradient magnetic field coil, a transmitting/receiving coil, and an upright bed arranged in an opposing space, and the upright bed is The subject is arranged so that the left and right direction of the subject coincides with the direction of the static magnetic field and is rotated around an axis that coincides with the direction of the static magnetic field, and is placed in the static magnetic field in the opposing space generated by the static magnetic field coil. The patient is placed on an upright bed, and a gradient magnetic field is applied to the patient by a gradient magnetic field coil, and a high-frequency magnetic field for excitation is applied by a transmitter/receiver coil to produce a magnetic resonance phenomenon in a specific part of the patient. By collecting magnetic resonance signals induced by this phenomenon using a transmitting/receiving coil and performing signal processing, at least one of morphological information and functional information of a specific region is visualized. Since a static magnetic field is generated in the space facing the static magnetic field magnet, the patient can be placed in various positions for diagnosis using the tilting bed. Therefore, the required installation space is smaller compared to the horizontal magnetic field method or vertical magnetic field method, and the installation conditions are relaxed.
Since the direction of the static magnetic field is perpendicular to the subject's body axis, various transmitting and receiving coils such as saddle coils, surface coils, and solenoid coils can be used as desired.

Therefore, according to the present invention, it is possible to provide a magnetic resonance diagnostic apparatus that can use various types of transmitting and receiving coils as desired, eases installation conditions, and allows diagnosis to be performed in various body positions.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of a magnetic resonance diagnostic apparatus according to the present invention, FIG. 2 is a diagram showing the operation of a reclining bed in the same embodiment, and FIG. 3 is a diagram showing another embodiment of the present invention. Figures 4 and 5 show the configuration of a conventional example, in which Figure 4 is a configuration diagram of a transverse magnetic field type device, and Figure 5 is a configuration diagram of a vertical magnetic field type device. FIG. 6 is a diagram showing a transmitting and receiving coil. 11, 20...Static magnetic field magnet, 11a, 20a...
... Yoke part, 11b1, 11b2 ... Leg part, 1c
1, 11c2, 20a1, 20a2...magnetic pole, 1
2...Gradient magnetic field coil, 13...Rising bed, 13
a... Top plate, 14... Gradient magnetic field power supply, 15... Transmitter/receiver, 16... Sequencer, 17... Computer system, 18... Monitor, 19... Bed control unit.

Claims (1)

[Claims] 1. a static magnetic field magnet having horizontally opposed magnetic poles, and a gradient magnetic field coil disposed in the opposing space;
comprising a transmitting/receiving coil and an upright bed, where the right and left direction of the subject coincides with the direction of the static magnetic field;
and placing the subject on the upright bed in a static magnetic field in the opposing space, which is arranged to rotate around an axis that coincides with the direction of the static magnetic field, and generated by the static magnetic field coil; A gradient magnetic field is applied to the subject by the gradient magnetic field coil, and a high-frequency magnetic field for excitation is applied by the transmitting/receiving coil to cause a magnetic resonance phenomenon in a specific part of the subject, and the phenomenon is induced by this phenomenon. A magnetic resonance diagnostic apparatus characterized in that the magnetic resonance diagnostic apparatus is configured to image at least one of morphological information and functional information of the specific region by collecting magnetic resonance signals with the transmitting and receiving coil and subjecting them to signal processing.