JPH01107749A - Magnetic resonance diagnostic device - Google Patents

Abstract

PURPOSE:To effect screening diagnosis easily without using a magnetization field magnet which is great and has a great uniformity, by a method wherein a roof is moved by a predetermined distance at every completion of a photographing sequence to effect the next photographing sequence. CONSTITUTION:A bed controller 15 may be operated manually through a computer system 9, and a console 10; when it receives an input of a signal PS indicating that a sheet of sliced image has been photographed, a roof 12a is automatically moved by distance l. A high-speed sequence is effected onto a location to obtain an image S11, which is observed by a monitor 11. When the photographing sequence has been completed, a sequence-completion signal PS is given to the bed controller 18, the roof 12a is moved by distance l, the similar sequence is effected to obtain an image S12 of the adjacent location. The roof movement and the next photographing sequence after the movement of the roof are carried out one by one; if only the initial setting is given by the operator, sliced images S11-S15, S21 and the followings in the aimed region may be obtained, thus the screening diagnosis in the aimed region may be conducted.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a magnetic resonance system that utilizes magnetic resonance phenomena to obtain diagnostic information such as slice images of specific parts of a subject. The present invention relates to a diagnostic device, and particularly relates to a magnetic resonance diagnostic device that can easily perform screening diagnosis even when the Vt configuration is downsized.

(Prior art) Magnetic resonance is a phenomenon in which an atomic nucleus with non-zero spin and magnetic moment placed in a static magnetic field resonantly absorbs and emits only electromagnetic waves of a specific frequency. The angular frequency ωa (ω0−2π shea, shea
; Larmor frequency).

ω0−γHII where γ is the gyromagnetic ratio specific to the type of atomic nucleus,
Further, He is the static magnetic field strength.

An apparatus that performs biological diagnosis using the above-mentioned principle processes the electromagnetic waves of the same frequency as the above induced after the above-mentioned resonance absorption, and calculates the nuclear density, longitudinal relaxation time TI, transverse relaxation time T2. Diagnostic information that reflects information such as flow and chemical shift, such as slice images of a subject, can be obtained non-invasively.

Collecting diagnostic information by magnetic resonance can excite all parts of a subject placed in a static magnetic field and collect signals, but there are limitations in the equipment configuration and clinical requirements for imaging images. Therefore, the actual device is designed to excite a specific region and collect its signals.

FIG. 3 is a diagram showing an example of a conventional configuration of this type of magnetic resonance diagnostic apparatus.

As shown in FIG. 3, the magnet assembly 1 is configured to accommodate the subject P inside.
It is equipped with a static magnetic field magnet (sometimes a shim coil for static magnetic field correction is added) 2 using a normal conduction or superconductivity method. This static magnetic field magnet 2 can generate a 40 to 50 cm gap within the subject introduction cavity 1a (generally in the center) with a magnetic field uniformity of several ppm, which is said to cause no problem with image quality. It looks like this. This jurisprudence space is called the diagnosable space V, and this diagnosable space V
It is possible to obtain a slice image of a desired part of the subject P placed inside the body.

Further, inside the magnet assembly 1, there is a gradient magnetic field generating coil 3 that generates a gradient magnetic field for imparting positional information of the induced site of the magnetic resonance signal, and a gradient magnetic field generating coil 3 that generates a gradient magnetic field for imparting position information of the induced site of the magnetic resonance signal, and a magnetic resonance signal (MR signal) that is induced while transmitting a rotating high frequency magnetic field. ) is provided with a probe 4 consisting of a coil, which is a transmission/reception system for detecting.

Furthermore, if the static magnetic field magnet 1 is a superconducting type, it includes a refrigerant supply control system, and mainly the static magnetic field magnet 1! Static magnetic field control system 5, X-axis for controlling power supply.

Controls the Y-axis and Z-axis gradient magnetic field power supplies 6, the transceiver 7, and the sequencer 8 that executes a predetermined imaging procedure, such as a sequence for obtaining a slice image of a single plane by the spin echo method or a sequence for obtaining a multi-slice image. It also includes a computer system 9, a console 10, and a monitor 11, which perform signal processing of detection signals and display thereof.

In addition, a bed 12 having a signboard 12a that can be slid
is installed facing the opening of the subject introduction cavity 1a of the magnet assembly 1, and this bed 12 is connected to the bed controller 13.
It can be controlled by a computer system 9 and a console 10 via.

With the above configuration, the shooting procedure begins with the console 1
0, the bed 12 is controlled and a desired diagnostic region of the subject P (in the figure, the abdomen) is placed within the diagnostic space V.

Next, by operating the console 10, the transmitter/receiver 7 is driven by a pulse sequence based on the spin echo method by operating the sequencer 8, for example, to apply a rotating magnetic field from the transmitting coil of the probe 4, and the gradient magnetic field power source 6 is driven to generate a gradient magnetic field. A gradient magnetic field is applied from the generating coil 3, and 1
A slice region to be selectively excited is set, a signal from the region is collected from the receiving coil of the probe 4, and the signal is imported into the computer system 9 and image reconstruction processing is performed.
A slice image of the region is obtained and displayed on the monitor 11.

The above is an explanation of the procedure for photographing one slice of the subject P, but with this type of image diagnostic equipment, this is called a screening diagnosis, which is a diagnostic method for finding a lesion site. A diagnostic method is performed.

In other words, in the example of Fig. 3, the diagnosable space ■ is 40 to 5
Since it is a 0 cm sphere, for example, if the abdomen of the subject P is placed in this space V, if a slice thickness of about 1 can be set, if the multi-slice method is performed in this state, it will be several 10 slices. slice images at different positions can be obtained.

If the multi-slice method is not used as an actual diagnostic procedure, first perform a sequence such as a spin echo method on a certain area to obtain a single image, which is then displayed on the monitor 11.
If the lesion cannot be found on this image, the lesion may be located at a different location (usually adjacent to this location).
Obtain a slice image of I! on the monitor 11 in the same way as the previous image. Sympathize. By sequentially performing this process, it becomes possible to locate the lesion.

In this case, in a normal sequence such as the spin echo method, 1
Although it takes several minutes to 110 minutes to obtain one slice image, if it is within the part of the subject P within the diagnosable space V, the application form of the gradient magnetic field can be changed to change the slice part. Since this is simply an electrical operation, it can be carried out extremely easily and is advantageous. In addition, by implementing the multi-slice method, several other slice images can be obtained with -1 imaging settings, making screening diagnosis even easier.

Therefore, in order to produce this advantage, the magnetic field uniformity must be several ppm.
It is necessary to generate a diagnosable space V of 40 to 50 cm. Therefore, the static magnetic field magnet 2 is large and highly uniform. However, considering that this type of magnetic resonance diagnostic apparatus is installed in a building such as a hospital, it is a problem if it is a large structure.

On the other hand, in order to solve the problem that Daiutago is a large structure,
A diagnosable space V with a magnetic field uniformity of several PPM at 10 to 20C
A configuration using a static 11-field magnet of m-sphere type is considered. However, with this configuration, the number of slice images that can be obtained by simply changing the application form of the gradient magnetic field is
Since the amount decreases by the amount that is smaller, in order to perform a screening diagnosis on a site similar to the above example, it is necessary for the subject P to move himself.

Therefore, it takes several minutes to several tens of minutes for one image to be displayed, so after this time, the console
There is the trouble of proceeding with the diagnosis while performing Aoidai control and changing the gradient magnetic field.

(Problems to be solved by the invention) In this way, in the conventional technology, in order to ensure the ease of screening diagnosis, it is necessary to use a static magnetic field magnet that is large and highly uniform. there were.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a magnetic resonance diagnostic apparatus that allows screening diagnosis to be easily performed without using a large and highly uniform static magnetic field magnet.

[Structure of the Invention] (Means for Solving the Problems) The present invention has a structure in which the following measures are taken to solve the above problems and achieve the object. That is, the present invention includes a bed having a top plate that can be slid,
The subject is placed on the top plate, and the static magnetic field generating means and the tilt l
A magnet assembly having an i-field generating means and an excitation high-frequency magnetic field generating means is introduced into a diagnosable space, and each of the magnetic field generating means is driven according to a predetermined photographic sequence, which is determined by the photographing sequence of the subject. In a magnetic resonance diagnostic apparatus that excites a region by magnetic resonance and collects magnetic resonance signals resulting from the excitation to generate a slice image of the region, the top plate is moved a predetermined distance at each end of the imaging sequence. It is characterized by comprising a control means for moving the camera and executing the photographing sequence in accordance with the movement.

(Function) According to this configuration, the top plate on which the subject is placed moves by a predetermined distance every time the imaging procedure is completed, and the imaging procedure is executed after this movement, so even if diagnosis is possible Even if the space is small, when screening and diagnosing a desired area, the slice site for the entire area can be changed by automatically moving the top plate without changing the application form of the inclined field 11. Even when a small, low-uniformity static magnetic field magnet with a small diagnostic space is used, screening diagnosis can be performed extremely easily.

(Embodiment) An embodiment of the magnetic resonance diagnostic apparatus according to the present invention will be described below with reference to FIG. 1, in which the same parts as in FIG. 3 are denoted by the same reference numerals.

FIG. 1 is a diagram showing the configuration of a magnetic resonance diagnostic apparatus according to this embodiment.

As shown in FIG. 1, the magnet assembly 14, which is capable of accommodating the subject P therein, is a static magnetic field magnet (with a static magnetic field correction shim coil added ) 15. This static magnetic field magnet 15 has a field uniformity of 20 to 30 PPM of several ppm, which is said to cause no problem with image quality.
cm, that is, a diagnosable space v' can be created within the subject introduction cavity 14a (generally in the central portion).

Further, within the magnet assembly 14, there is a gradient magnetic field generating coil 16 that generates a gradient magnetic field for imparting positional information of the induced site of the magnetic resonance signal, and a magnetic resonance signal (MR) that is induced while transmitting a rotating high-frequency magnetic field. The device is equipped with a probe 17 consisting of a coil, which is a transmission/reception system for detecting signals (signals).

Furthermore, a static magnetic field control system 5, an X-axis, a Y-axis, a two-axis gradient magnetic field 1
! m6, a transmitter/receiver 7', a sequencer 8 for executing a predetermined photographing sequence, a computer system 9 for controlling these and for processing and displaying detection signals, a console 10, and a monitor 11.

Here, the X-axis, Y-axis, two-axis gradient magnetic field power supply 6, transmitter/receiver 37
, a sequencer 8 that executes a predetermined imaging sequence is 1
The apparatus is configured to perform high-speed sequence and high-speed double-sided reconstruction in which the time required from the start of imaging to the completion of image generation is several tens of milliseconds to several hundreds of milliseconds for several slice images.

Furthermore, the sequencer 8 is capable of executing a sequence for obtaining a raw-plane slice image and a sequence for obtaining a multi-slice image.

Furthermore, the bed 1 has a top plate 12a that can be slid.
2 is the subject introduction cavity 14 of the magnet assembly 14
This bed 12 is installed facing the opening of the bed 12, and can be controlled by a computer system 9 and a console 10 via a bed controller 18.

The bed controller 18 described above is operated by a computer system 9.
Manual operation is possible using the console 10, and when a signal PS indicating that one slice image has been captured is input to the computer system 9, the top plate 12a is automatically moved by a distance 11iR. When a command is input or a signal PM indicating that the multi-slice image has been taken is input, the top plate 12a is automatically moved by a distance L (corresponding to the thickness of the image taken in one multi-slice image). A command to move the bed 12 is given to the bed 12.

With the above configuration, the patient P's abdomen, for example, is placed in the diagnosable space (-) by manual operation using the computer system 9 and the console 10, and the transmission/reception 37 is performed in a high-speed sequence by the operation of the sequencer 8 by the operation of the console 10. For example, a rotating magnetic field is applied from the transmitting coil of the probe 4, and a gradient magnetic field is applied from the gradient magnetic field generating coil 3 by driving the gradient magnetic field power supply 6, and one slice region to be selectively excited is set, and from that region. The signals are collected from the receiving coil of the probe 4, are input into the computer system 9, and subjected to high-speed image reconstruction processing to obtain a slice image of the region, which is displayed on the monitor 11. This one slice image.

It can be obtained in several tens of milliseconds to several hundred milliseconds.

The above describes the procedure for Wlllling one slice site, but the diagnosable space V- is 20 to 3 Qcm.
Since it is a sphere, if, for example, the abdomen of the subject P is placed in this space V', if a slice thickness of about 1I11 can be set, then in this state, according to the multi-slice method,
Several slice images at different positions can be obtained.

Next, the operation of the apparatus of this embodiment constructed as described above will be explained. First, as a procedure for actual screening diagnosis,
A case will be described in which a sequence for obtaining a width-plane slice image is executed. That is, as shown in Fig. 2, a high-speed sequence is executed for a certain part to create one image IE.
Obtain tS11 and display it on monitor 11 as I! Sympathize. At the end of this shooting sequence, the sequence end signal P
S is given to the table controller 18, and the top plate 12a is set at a distance #I°C.
6812 of the adjacent region can be obtained by moving by 6812 and executing the same imaging sequence as described above. This movement of the top plate and the execution of the shooting sequence after this movement are performed sequentially, so
The surgeon only needs to make initial settings to create slices aS11.812.813°814,815.3 within the desired area.
21~, that is, it becomes possible to perform screening diagnosis within a desired area.

In this example, by automating the diagnostic procedure for setting the slice region, the diagnosable space can be narrowed from V to v' without increasing the time required for diagnosis and without complicating the operation. Screening diagnosis can be performed easily as in the past, and the static m-field magnet 14 is small and has a low uniformity that can generate a diagnosable space of 20 to 3 QCm with a magnetic field uniformity of several ppm. This is advantageous in terms of equipment installation conditions, etc.

In addition, in a conventional sequence such as a spin echo method, it takes several minutes to several tens of minutes to obtain one slice image, but in this embodiment, one slice image can be obtained from the start of imaging. It is configured so that it can perform high-speed sequences and high-speed image reconstruction in which the time required to complete image generation is from several tens of milliseconds to several hundreds of milliseconds.
The diagnosis time is short and the time for restraining the subject P is also short, which is advantageous.

The above example concerns the case where a sequence for obtaining a single-plane slice image is executed, but the case where a sequence for obtaining a multi-slice image is executed is as follows.

That is, as shown in FIG. 2, a high-speed multi-slice sequence is performed on a certain region. This results in
Slice image S 1 (Si1.812.813.814
．． 815) is obtained, and at this time, the sequence end signal PM
is applied to the bed controller 18, and the top plate 12a moves by the distance. After this movement of the top plate, the same photographing sequence as described above is executed, and the slice image S2 (821, S22°S
23.824.825) is obtained. This movement of the tabletop and the execution of the m-shadow sequence after this movement are performed sequentially, so the operator only needs to make the initial settings and perform the same procedure as the above-mentioned sequence for taking slice images of a single plane to locate within the desired area. Slice images of 811°812, 813.814.8
15.821~1! In other words, it becomes possible to perform screening diagnosis within the desired mR.

Note that in the above example, the tabletop is automatically moved and the sequence is automatically started when the sequence for taking a single-plane slice image or the sequence for taking a multi-slice image is completed. When a predetermined number of images have been taken, the top plate may be automatically moved and the sequence may be automatically started.

Moreover, the image obtained by the above-mentioned screening may be used as a positioning image for precise diagnosis.

In addition, various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] As described above, according to the present invention, by providing a control means for moving the top plate by a predetermined distance every time N shadow sequences are completed and executing the photographing sequence after this movement, it is possible to The top plate on which the patient is placed moves a predetermined distance each time the imaging procedure is completed, and the imaging procedure is executed after this movement, so even if the diagnostic space is small, the desired area can be screened and diagnosed. In this case, the slice location for the entire region can be changed by automatically moving the top plate without changing the application form of the gradient magnetic field. Even when a field magnet is used, screening diagnosis can be performed extremely easily.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of the magnetic resonance diagnostic device according to the present invention, FIG. 2 is a diagram for explaining the operation of the same embodiment, and FIG. 3 is a diagram showing the configuration of a conventional example. It is. 5... Static magnetic field control system, 6... Gradient magnetic field power supply, 7...
- Transmitter/receiver, 8... Sequencer, 9... Computer system, 10... Console, 11... Monitor, 12... Bed, 12a... Top plate, 14... Magnet assembly, 15 ...Static magnetic field magnet, 16...
・Gradient 1itl field coil, 17... Probe, 18・
...Bed controller, V, V-...Diagnostic space. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (3)

[Claims] (1) Diagnosis of a magnet assembly that is equipped with a bed having a top plate that can be slid, and a subject is placed on the top plate, and includes a static magnetic field generating means, a gradient magnetic field generating means, and a high-frequency magnetic field generating means for excitation. By introducing the device into a possible space and driving each of the magnetic field generating means according to a predetermined imaging procedure, a region of the subject determined by the imaging procedure is excited by magnetic resonance, and a magnetic resonance signal due to the excitation is collected. The magnetic resonance diagnostic apparatus is configured to generate a slice image of the region using a magnetic resonance diagnostic apparatus, further comprising a control means for moving the top plate by a predetermined distance each time the imaging procedure is completed and executing the imaging sequence after this movement. A magnetic resonance diagnostic device featuring: (2) The magnetic resonance diagnostic apparatus according to claim 1, wherein the imaging procedure is a sequence for obtaining a slice image of a single plane. (3) The magnetic resonance diagnostic apparatus according to claim 1, wherein the imaging procedure is a sequence for obtaining multi-slice images.