JP4532145B2 - MRI equipment - Google Patents

Description

  The present invention relates to a magnetic resonance imaging (hereinafter abbreviated as MRI) apparatus that displays an image of an arbitrary cross section of a subject using a nuclear magnetic resonance (hereinafter abbreviated as NMR) phenomenon, and particularly relates to a connection technique of a receiving coil. .

A signal received by the receiving coil of the MRI apparatus is sent to a high-frequency transmitting / receiving unit that also serves as a reception through a preamplifier (preamplifier), digitized, and then sent to a computer for image reconstruction. Thus, although the receiving coil is connected to the preamplifier, the preamplifier is often built in the bed, and the connection between the receiving coil and the preamplifier is made through a connector and a cable.
Also, multiple types of receiving coils are prepared according to the body shape and imaging region of the subject, and considering the convenience of setting the receiving coil according to the exchange of the receiving coil or imaging conditions, the receiving coil and preamplifier are It is connected via a flexible cable. Further, in order to improve the convenience of setting the receiving coil position, as shown in [Patent Document 1] and [Patent Document 2], the preamplifier slides along the guide groove provided in the bed, A method has been proposed in which a receiving coil connected by a cable moves together with a preamplifier.
Further, as shown in [Patent Document 3], a method of installing a plurality of connectors on a bed has been proposed.
Japanese Patent Laid-Open No. 5-130978 Japanese Patent Laid-Open No. 10-295666 JP-A-6-315473

As described above, in order to move the position of the receiving coil in the MRI apparatus, the position of the receiving coil is moved within the movable range of the cable with respect to the fixed preamplifier, or the preamplifier, the cable, and the receiving coil are moved simultaneously. One of them.
However, in the above structure, there is a problem in durability, such as an increase in the load on the cable and the connector depending on how to handle the receiving coil exchange for each photographing. Moreover, although the said cable is for connecting a receiving coil and a preamplifier, it is not an essential member. If the receiving coil and the bed are in contact with each other at least one place, it is possible to connect the receiving coil and the preamplifier without a cable.
An MRI apparatus that does not have such movable parts such as cables and slides and that can adjust the position of the receiving coil is not disclosed in the above-mentioned known document.

The present invention has been made to solve the above-mentioned problems, and the object thereof is as follows. That is, the first purpose is to eliminate moving parts of the receiving coil such as cables and slides. The second object is to make it possible to adjust the arrangement position of the receiving coil in a flexible manner corresponding to the body shape and imaging region of the subject.

In order to solve the above problems, the present invention is configured as follows. That is,
(1) a bed of moving to the static magnetic field center by supporting the patient, receiving means for receiving nuclear magnetic resonance signals from the subject is placed on the bed, it is connected before Symbol receiving means In the magnetic resonance imaging apparatus comprising the amplifying means for amplifying the nuclear magnetic resonance signal, the receiving means includes a first connector for outputting the received signal, and the bed is connected to the first connector. A plurality of second connectors obtained in the longitudinal direction of the bed, wherein the amplifying means is connected to the plurality of second connectors by a cable and from the second connector to which the first connector is connected The received signal is selected and amplified.
Accordingly, the receiving coil can be directly connected to the bed without using a cable corresponding to the position of the imaging region of the subject .

(2) In a preferred embodiment, the receiving means further comprises a plurality of the first connectors, any one of which is connected to the second connector.
As a result, the number of combinations of the first connector and the second connector can be dramatically increased. By changing the connection combination of the first connector and the second connector, the receiving coil is arranged on the bed. The position can be finely adjusted .

(3) In addition, one preferred embodiment, the magnetic resonance imaging apparatus according to claim 1 or 2, a plurality of pre-Symbol receiving means, receiving means disposed in the static magnetic field center from the plurality of receiving means And amplifying means for receiving received at the center of the static magnetic field when the first connectors of the plurality of receiving means are simultaneously connected to the different second connectors, respectively. The received signal from the second connector to which the means is connected is selected and amplified.
Thereby, when performing whole body imaging | photography or wide range imaging | photography using a some receiving coil simultaneously, each receiving coil can be optimally arrange | positioned corresponding to the position of each imaging | photography area | region .

  As described above, according to the present invention, by providing a plurality of connectors for installing a receiving coil on a bed, it is possible to flexibly at a desired portion without providing a movable portion of a receiving coil such as a conventionally used cable or slide. It is possible to shoot corresponding to As a result, it is possible to improve the durability of the receiving coil by reducing the chances of handling errors by the operator.

  First, an outline of an MRI apparatus to which the present invention is applied will be described with reference to FIG. This MRI apparatus generates a gradient magnetic field in the Y direction, a static magnetic field generation means 1 that applies a static magnetic field to the subject 12, an X-direction gradient magnetic field generation means 2 that generates a gradient magnetic field in the X direction in an XYZ orthogonal coordinate system. Y-direction gradient magnetic field generation means 3, Z-direction gradient magnetic field generation means 4 for generating a gradient magnetic field in the Z direction, gradient magnetic field power supply 5 for supplying power to each of the gradient magnetic field generation means, and the imaging region of the subject An irradiation coil 6 that irradiates a high-frequency magnetic field, a reception coil 7 that receives a high-frequency magnetic field emitted by nuclear magnetic resonance of the biological tissue of the subject, a high-frequency magnetic field power supply 8 that supplies power of the irradiation high-frequency magnetic field, and the above The high-frequency transmission / reception unit 9 that performs irradiation and reception of a high-frequency magnetic field, the gradient magnetic field power source and the high-frequency transmission / reception unit are controlled in accordance with a pulse sequence, and the computer 10 that performs image reconstruction calculation using the received signal, and the computer The display 11 is configured to input a generated image signal and display it as a tomographic image, and a bed 13 that carries the subject into the static magnetic field generating means.

Next, a first embodiment of the present invention will be described. In this embodiment, a plurality of connecting portions (connectors) are provided on the bed or the reception coil so that the arrangement of the reception coil can be changed corresponding to the imaging region of the subject, that is, the imaging region of the subject. The receiving coil is arranged at the position closest to
Thus, by installing a plurality of coils on the bed, it is possible to eliminate the movable parts of the receiving coil such as cables and slides that are conventionally used, and it is possible to photograph a desired part. By eliminating the coil moving part, the operator's chance of handling defects can be reduced, and the durability of the coil can be improved.

Hereinafter, examples of the present embodiment will be described in detail.
FIG. 1 shows an example of the first embodiment. In FIG. 1, in the XYZ orthogonal coordinate system, five connectors 21 to 25 are arranged on the bed 13 at intervals d in the Z direction. This connector shape is a pin connection type. Each connector is connected to cables 26 to 30 for transmitting received signals and control signals, and the other end of each cable is connected to the preamplifier 20 inside the bed 13 (in FIG. 13 Although the preamplifier 20 is described outside, it is assumed that the preamplifier 20 is actually arranged inside the bed 13. The same applies to the cables 26 to 30.) The signal from the preamplifier 20 is further sent to the transmission / reception unit 9, and the signal is transmitted to the computer 10 through this. It is desirable that the cables 26 to 30 are joined before the preamplifier 20 or only the corresponding cable is electrically connected to the preamplifier 20 together with the selection of the connector. For example, when the connector 21 is selected, the preamplifier 20 and the cable 26 are electrically connected according to a command from the computer 10. The connector is identified by, for example, a short circuit between the connected coil and the connector pin. For example, if three pins are assigned to connector identification, it is possible to identify up to 2 ³ = 8 connectors by combinations of pins that are short-circuited.

  The shape of the bed 13 is a plane. Assuming that Z = 0 is the magnetic field center in the Z direction and the center of the connector 23 is initially located at the magnetic field center (0, 0, 0), the coordinates of the connector 21 to the connector 25 are (0, 0, −2d), respectively. , (0, 0, −d), (0, 0, 0), (0, 0, d), (0, 0, 2d). The direction of the subject 12 is such that the connector 21 side is the head and the connector 25 side is the foot. However, the reverse is also possible. In order to perform head imaging, the connector 32 of the head receiving coil 31 is installed on the connector 21, and the bed 13 is slid 2d in the + z direction.

  FIG. 2 shows the connection between the connector 32 and the connector 21 of the head receiving coil 31 as viewed from the z direction. The center coordinates of the connector 32 after the connector 32 is connected to the connector 21 and the bed is slid are (0, 0, 0).

  Next, in order to take a picture of the shoulder, the shoulder surface type receiving coil 33 shown in FIG. 3 is installed in the connector 22, and the bed 13 is slid in the + z direction. FIG. 4 shows how the connector 34 and the connector 22 of the shoulder receiving coil 33 are viewed from the z direction. The center coordinates of the connector 34 after the connector 34 is connected to the connector 22 and the bed is slid are (0, 0, 0).

  In order to further photograph the abdomen, the abdomen receiving coil 35 shown in FIG. 5 is installed in the connector 23, and the bed 13 is slid 0 times in the + z direction. FIG. 6 shows how the connector 36 and the connector 23 of the abdominal receiving coil 35 are viewed from the z direction. The center coordinates of the connector 36 after the connector 36 is connected to the connector 23 and the bed is slid are (0, 0, 0).

  Thereafter, the legs can be photographed in the same manner. It is obvious that the present invention can be applied to coils other than the receiving coil used in the description of the first embodiment. Further, the number and arrangement of connectors are not limited to the above embodiments. For example, the effect of the present invention can be further improved if the connectors are densely arranged at a site where the imaging frequency is high.

  The above is an embodiment in which a plurality of connectors are installed on the bed 13 side, but the subject may be slightly moved on the bed 13 depending on individual differences in the body shape of the subject or imaging conditions. Therefore, the second implementation of dramatically increasing the installation location of the receiving coil by arranging a plurality of connectors on the receiving coil side and increasing the number of combinations of the connector on the bed 13 side and the connector on the receiving coil side. An example will be described with reference to FIG.

FIG. 7 shows an example in which three connectors 81, 82, 83 are arranged in the x direction at intervals h in the head receiving coil 31. Assuming that the head receiving coil 31 is connected to the connector 21, the coordinates of the connectors 81 to 83 are (-h, 0, 0), (0, 0, 0), (h, 0, 0). The same is possible with the connectors 22-25. Depending on the combination of the connector on the receiving coil side and the connector on the bed side, the position of the receiving coil is
(−h, 0, −2d), (−h, 0, −d), (−h, 0, 0), (−h, 0, d), (−h, 0, 2d),
(0,0, -2d), (0,0, -d), (0,0,0), (0,0, d), (0,0,2d),
(h, 0, -2d), (h, 0, -d), (h, 0,0), (h, 0, d), (h, 0,2d)
You can choose from 15 different arrangements.
Here, it is preferable to attach covers to the connectors 21 to 25 so that pins are not exposed when not in use. For example, a mechanism may be considered in which when the connector of the receiving coil is inserted into the connector on the bed side, the connector cover on the bed side is woven into the bed and the connector is exposed.

Next, a second embodiment of the present invention will be described. The present embodiment is an embodiment in which the present invention is applied to whole body imaging, particularly whole body blood vessel imaging, and a desired imaging region using a plurality of receiving coils simultaneously when sequentially imaging the whole body or a wide area of a subject. Each receiving coil is arranged to include
This makes it possible to easily adjust the position of the receiving coil installed corresponding to the body shape of the subject and the position of each imaging region when imaging a wide area.

  FIG. 8 shows an example of the second embodiment. FIG. 8 shows an example of whole body imaging in which the whole body of the subject 12 is imaged by dividing it into five regions. In the case of whole body imaging, the imaging area is moved to the center of the magnetic field with good magnetic field uniformity for each imaging. For this reason, a plurality of receiving coils are simultaneously arranged so as to cover each imaging region of the subject before imaging, and the bed is placed so that the next receiving coil comes to the center of the magnetic field while the subject is placed for each imaging. Move. Further, when the receiving coils are arranged, the arrangement of the receiving coils is selected by selecting the connectors in the Z direction and the X direction so that the desired imaging region is located at the approximate center of the receiving coil. In FIG. 8, five receiving coils 71 to 75 are simultaneously arranged so as to cover each imaging region of the subject 12 before imaging.

  When shooting, the shooting of each shooting area and the movement of the bed 13 are sequentially repeated. When the receiving coil that moves the bed 13 and covers each shooting area is placed at the center of the magnetic field, the previous cable is used. And the preamplifier are disconnected from each other, and the preamplifier is electrically connected to the cable newly connected to the connector of the receiving coil disposed at the center of the magnetic field. The selection of the receiving coil is performed by, for example, selectively bringing the desired receiving coil into a receivable state by passing a current through a decoupling circuit of the desired coil (a circuit that activates the coil only during reception). be able to. The current can be supplied to the decoupling circuit by a switching circuit such as a relay. Furthermore, the desired coil can be moved to the center of the magnetic field by recognizing the connector position and recognizing the accumulated movement distance of the bed. This is because the initial position of the bed 13 with respect to the center of the static magnetic field and the connector position on the bed 13 are known. The cumulative movement distance of the bed 13 can be recognized, for example, by counting an encoder provided in a motor that drives the bed 13. The bed 13 is moved automatically after the photographing of each photographing region is completed or according to an instruction from the operator.

  Alternatively, when only one receiving coil is used, the bed 13 is taken out every time imaging of each imaging area is completed, the receiving coil is replaced so that the center is arranged in the next imaging area, and the magnetic field center is again The subject 12 is inserted into and the next imaging region is imaged. These operations are repeated as many times as necessary.

  For example, in the case of FIG. 1, the receiving coil is sequentially replaced from the connector 21 toward the connector 25 or from the connector 25 toward the connector 21, and imaging and bed feeding are repeated.

The figure at the time of connecting a head receiving coil to a bed. The figure which shows the mode of the connection of the connector of the receiving coil for heads, and the bed connector seen from the Z direction. The figure at the time of connecting the surface type receiving coil for shoulders to the bed. The figure which shows the mode of the connection of the connector of the surface type receiving coil for shoulders, and the bed connector seen from the Z direction. The figure at the time of connecting the receiving coil for abdomen to the bed. The figure which shows the mode of the connection of the connector of the receiving coil for abdominals and the bed connector seen from the Z direction. The figure which shows the example which has arrange | positioned three connectors to the X direction for the receiving coil for heads. The figure at the time of connecting each receiving coil to a bed for whole body photography simultaneously. 1 is a schematic configuration diagram of an MRI apparatus to which the present invention is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Static magnetic field generation means, 2 ... X direction gradient magnetic field generation means, 3 ... Y direction gradient magnetic field generation means, 4 ... Z direction gradient magnetic field generation means, 5 ... Gradient magnetic field power supply, 6 ... Irradiation coil, 7 ... Reception coil, DESCRIPTION OF SYMBOLS 8 ... High frequency magnetic field power supply, 9 ... High frequency magnetic field transmitter / receiver, 10 ... Computer, 11 ... Display, 12 ... Subject, 13 ... Bed

Claims (4)

A bed on which the subject is placed and moved to the center of the static magnetic field;
Receiving means mounted on the bed for receiving a nuclear magnetic resonance signal from the subject;
In a magnetic resonance imaging apparatus comprising an amplifying means connected to the receiving means for amplifying the nuclear magnetic resonance signal,
The receiving means includes a first connector that outputs the received signal without going through a cable ,
The bed includes a plurality of second connectors that can be connected to the first connector in the longitudinal direction of the bed,
The amplifying means is connected to the plurality of second connectors by a cable, and selects and amplifies a received signal from the second connector to which the first connector is connected. Resonance imaging device. A bed on which the subject is placed and moved to the center of the static magnetic field;
Receiving means mounted on the bed for receiving a nuclear magnetic resonance signal from the subject;
In a magnetic resonance imaging apparatus comprising an amplifying means connected to the receiving means for amplifying the nuclear magnetic resonance signal,
The receiving means includes a plurality of first connectors for outputting the received signals,
The bed includes a plurality of second connectors that can be connected to any one of the plurality of first connectors in the longitudinal direction of the bed,
The amplifying means is connected to the plurality of second connectors by a cable, and selects and amplifies a received signal from the second connector to which the first connector is connected. Resonance imaging device. The magnetic resonance imaging apparatus according to claim 1 or 2, comprising a plurality of the receiving means,
A means for recognizing the receiving means arranged at the center of the static magnetic field from the plurality of receiving means,
When the first connectors of the plurality of receiving means are simultaneously connected to the different second connectors, the amplifying means is connected to the receiving means arranged at the center of the static magnetic field. A magnetic resonance imaging apparatus, wherein a received signal from a connector is selected and amplified.   4. The magnetic resonance imaging apparatus according to claim 1, wherein the amplification unit is disposed inside the bed. 5.

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