JPH10272116A - RF coil for magnetic resonance diagnostic equipment - Google Patents

Abstract

(57) [Summary] (With correction) [PROBLEMS] To enable the shape of an RF coil to be stabilized and to be able to set the RF coil in close contact with a subject. SOLUTION: A pair of loop circuit electric circuits 2A and 2B and eight loop coupling circuit electric circuits 3 are provided on a flexible substrate 1,
Connectors 7a, 7b, 8a, 8b for connecting both ends of the loop circuit electric circuits 2A, 2B are attached,
A large number of blocks 10 each having a trapezoidal cross-section are arranged side by side on the inner surface when the flexible substrate 1 is curved into a cylindrical shape in order to wind the flexible substrate 1 around the subject, and along the opposing long sides of the flexible substrate 1. Is provided. The flexible substrate 1 is wrapped around the subject with the surface on which the shape regulating member 9 is attached facing inward, and the connector 7
When a, 7b, 8a, and 8b are connected, the blocks 10 come into close contact with each other, and the flexible substrate 1 is held in a predetermined curved shape (cylindrical or elliptical cylindrical shape) regulated by the blocks 10, and Can be attached in close contact with the sample.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic resonance diagnostic apparatus (hereinafter, referred to as an MRI apparatus) for performing imaging and spectroscopy measurement utilizing a nuclear magnetic resonance phenomenon (MR phenomenon). The present invention relates to an RF coil that receives a signal (NMR signal), and more particularly to an RF coil that is used by being wound around a portion to be inspected of a subject, that is, a so-called wrap-around RF coil.

[0002]

2. Description of the Related Art A wrap-around type RF coil 51 comprises:
As shown in FIG. 5, a coil pattern, for example, a circular loop circuit 53 and an 8-shaped loop circuit 54 are formed on a flat flexible substrate 52, and one end of the flexible substrate is provided with a coupling member such as a magic fastener. 55 and 56 are provided. At the time of imaging, as shown in FIG. 6, the flat flexible substrate 52 is curved and wound around an imaging site such as the abdomen of the subject, and the magic fastener 55, 5
6 are coupled to each other to form a cylindrical (cylindrical) coil, a circular loop 53 receives an NMR signal in a vertical direction, and an 8-shaped loop circuit 54 receives an NMR signal in a horizontal direction.

A wrap-around type RF coil is wound around an imaging part such as the abdomen of the subject, so that it can be in close contact with the subject. Therefore, the sensitivity is good and the S / N ratio is high, but the shape of the RF coil becomes unstable. RF depending on shape
There is a disadvantage that the image becomes non-uniform due to a change in the receiving characteristic of the coil. From this, in order to stabilize the shape of the RF coil, for example, a semi-cylindrical shape holder 57 is attached to the subject as shown in FIG.
The shape of the RF coil is stabilized by winding the flat flexible substrate 52 around the outer peripheral surface of the shape holder 57.

[0004]

However, in the case of stabilizing the shape of the RF coil using the shape holder, the shape holder is required, and it takes a long time to mount the RF coil on the subject (setting). And the setting is troublesome, and the RF coil cannot be set in close contact with the subject.

[0005] In view of the above, the present invention can stabilize the shape of the RF coil by winding it around the subject and joining both ends with a joining member, and can set the RF coil in close contact with the subject. An object of the present invention is to provide an RF coil for an MRI apparatus that can be performed simply and in a short time and that is lightweight.

[0006]

In order to achieve the above object, an RF coil for a magnetic resonance diagnostic apparatus according to the present invention uses a connecting member for removably connecting both ends of a flexible substrate having a predetermined coil pattern. It is characterized in that a shape regulating member for regulating the curved shape is provided at both peripheral end portions or a central portion of a surface which is connected to and formed inside when curved into a cylindrical shape (tubular shape).

According to such a configuration, since the flexible substrate having the predetermined coil pattern has flexibility, the flexible substrate may be bent into a cylindrical shape (cylindrical shape) to be wound around the subject, or may be formed into a planar shape. Can be expanded to. Further, a shape regulating member that regulates the curved shape is provided at both peripheral end portions or a central portion of a surface that is inside when the flexible substrate is curved into a cylindrical shape (tubular shape). The flexible board is wound around the subject while the shape regulating member is on the inner side and in close contact with the subject, and the ends are connected by a detachable connecting member. In the state where the flexible substrate is wound around the subject and the ends thereof are connected by the connecting member, the flexible substrate holds a predetermined curved shape (cylindrical or elliptical cylindrical shape) by the action of the shape regulating member, and the RF coil regulates the shape. Maintains a stable shape defined by the member and does not deform.

Therefore, the RF coil can be set in close contact with the subject, the shape of the RF coil can be stabilized, and the setting can be performed easily and in a short time. Further, since the shape regulating members are provided at both ends of the flexible substrate or at the center thereof, the weight of the RF coil can be reduced.

[0009]

Next, embodiments of the present invention will be described in detail with reference to the drawings. 1A and 1B are views showing a state in which a connecting member (connector) of an RF coil of an embodiment is released and developed in a planar shape, wherein FIG. 1A is a plan view, FIG. 1B is a front view and FIG. . FIG. 2 is a sectional view showing a layer structure of the RF coil of the embodiment, and FIG. 3 is an RF coil of the embodiment.
FIG. 4 is a perspective view showing a procedure for mounting (setting) the coil on the subject, and FIG. 4 is a partial cross-sectional view for explaining the operation of the shape regulating member in the connection state and the disengagement state of the connector of the RF coil of the embodiment.

As shown in FIG. 1, the RF coil C has a rectangular sheet-shaped flexible substrate 1, and in this embodiment, in the embodiment, loop circuit electric circuits 2A, 2B and 8 constituting a birdcage type RF coil. The RF coil patterns of the three loop-coupling circuit electric paths 3 are formed. The loop circuit electric circuits 2A and 2B are conductive portions extending along both peripheral ends of a surface which is inside when the flexible substrate 1 is curved into a cylindrical shape (cylindrical shape), that is, along opposing long sides of the flexible substrate 1. Each of the loop-coupling circuit electric circuits 3 is a conductive path provided so as to connect the loop-circuit electric circuits 2A and 2B at appropriate intervals. Further, in the embodiment, in order to obtain a low-pass filter type birdcage RF coil, each loop-coupling circuit electric path 3 is a conductive path through which a capacitor element 4 for resonance or the like is interposed.

On the other hand, the flexible substrate 1 is provided with a polycarbonate layer 1b having a thickness of about 1 mm on the back surface of a polyimide layer 1a having a thickness of about 70 μm, and a cushioning material layer 1c on the front surface. The loop circuit electric paths 2A and 2B, the loop connection circuit electric path 3 and the capacitor element 4 formed by the printed wiring technique are provided on the polyimide layer 1a. The polycarbonate layer 1b is a polyimide layer 1
If only a is used, the waist is too weak, so it is a so-called backing material (shape stabilizing material) for giving the flexible substrate 1 the necessary waist. The buffer material layer 1c is for protecting each electric circuit and the capacitor element provided in the polyimide layer 1a.

Also, both short sides of the flexible substrate 1 (two opposing sides which abut when curved and cylindrical).
Plug connectors 5a and 7b are provided with plug connectors 7a and 7b, and socket connectors 8a and 8b that can be connected to and disconnected from the plug connectors 7a and 7b. The connectors 7a and 7b are provided with connection pins at the ends, the connectors 8a and 8b are provided with sockets for receiving the connection pins, and the connection pins of the connectors 7a and 7b are inserted into the sockets of the connectors 8a and 8b, respectively. It is configured to be in an electrically connected state. On the other hand, the left ends of the loop circuit electric circuits 2A and 2B are connected to the connectors 7a and 7b, respectively, and the right ends are connected to the connectors 8a and 8b, respectively.

Accordingly, when the flexible substrate 1 is bent into a cylindrical shape and the connectors 7a and 8a are connected, both ends of the loop circuit electric circuit 2A are short-circuited, so that the loop circuit electric circuit 2A forms a loop circuit. When the connectors 7b and 8b are connected, both ends of the loop circuit electric circuit 2B are short-circuited, so that the loop circuit electric circuit 2B forms a loop circuit. In addition, a cable k for connection between the RF coil of the embodiment and the control console is provided.
1, k2 are also provided as appropriate. Further, a shape regulating member 9 which is a main part of the present invention is provided on an inner surface when the flexible substrate 1 is curved in a cylindrical shape in order to wind the flexible substrate 1 around the subject, that is, a surface facing the subject when the flexible substrate 1 is mounted on the subject. Is provided by pasting or the like. In the embodiment, the shape regulating member 9 is configured by arranging a large number of blocks 10 each having a trapezoidal cross section, and the blocks 10 are provided along opposing long sides of the flexible substrate 1. In the disengaged state of the connector 7a and the connector 8a, and the connector 7b and the connector 8b, they can be developed in a plane as shown in the figure. The block 10 is made of a material that is not deformed by a compressive or compressive force. The long side where the shape regulating member 9 is provided is
When the flexible substrate 1 is curved and formed into a cylindrical shape, it becomes a peripheral end portion. Further, cushion members 11 are provided between the blocks 10 constituting the shape regulating member 9 and on the upper surface thereof.
Is provided.

In order to mount the RF coil having the structure shown in FIG. 1 on an examination site of a subject, for example, an abdomen, first, FIG.
As shown in (a), the connection between the connector 7a and the connector 8a and the connection between the connector 7b and the connector 8b are released, and the RF coil is mounted on the bed on which the subject M is placed with the flexible substrate 1 expanded. Place on plate 12. Next, FIG.
As shown in (b), the subject M is placed on the top plate 12 such that the abdomen is located on the flexible substrate 1. Next, as shown in FIG. 3 (c), if the connection between the connector 7a and the connector 8a and the connection between the connector 7b and the connector 8b are performed by winding the abdomen of the subject M around the flexible substrate 1, the RF coil is mounted. Is completed.

Thus, the RF on which the subject M has been mounted is completed.
The coils are a connector 7a, a connector 8a and a connector 7b.
And the connector 8b are in a connected state, and the flexible substrate 1 is a cylindrical body. Since this cylindrical body is flexible and can be brought into close contact with the subject M, the NMR signal can be received with high sensitivity. When the connector 7a and the connector 8a and the connector 7b and the connector 8b are connected to each other, the two loop circuit electric circuits 2A and 2B extending along the circumferential direction of the cylindrical body, and extending along the cylindrical axis direction. Since the low-pass filter type birdcage RF coil is formed in such a manner that the abdomen which is the imaging site is inward in the loop connection circuit circuit 3, the birdcage type RF coil generates a signal from the abdomen of the subject M. N
MR signals can be received from all around the abdomen. In FIG. 3, the shape regulating member 9 is omitted.

In this manner, in a state where the RF coil C is wound around the imaging site of the subject M and the connectors 7a and 8a and the connectors 7b and 8b are connected, each block 10 is connected as shown in FIG. They come into close contact with each other and have a predetermined shape determined by the shape of the block 10 and the like, for example, a cylindrical shape and an elliptic cylindrical shape. Since each block 10 is made of a material that does not deform, the RF coil C keeps a stable shape in close contact with the imaging site of the subject M and does not deform. In addition, the shape, size, and number (the number of divisions) of the blocks 10 constituting the shape regulating member 9 are determined so as to conform to the shape of the imaging region according to the shape of the imaging region.

The present invention is not limited to the above embodiment, but can be modified as follows. (1) In the RF coil of the above embodiment, the shape regulating members are provided along the long sides at both peripheral ends of the flexible substrate, but may be provided in the center parallel to the long sides, and are limited to blocks. Not done. (2) Although the coil pattern of the above-described embodiment is a low-pass filter birdcage RF coil, a high-pass filter birdcage RF coil and a bandpass birdcage RF coil are formed. It may be a coil pattern. In the embodiment,
Although the number of loop-coupling circuit electric circuits connecting the pair of opposing loop-circuit electric circuits is eight, the number of loop-coupling circuit electric circuits is not limited to eight.

(3) In the RF coil of the above embodiment, the coil pattern is formed on the flexible substrate by the printed wiring technique. However, the coil pattern may be formed by attaching a foil plate to the flexible substrate.

(4) The RF coil of the above embodiment is a birdcage type RF coil.
As exemplified above, an RF coil including a circular loop circuit and an 8-shaped loop circuit may be used. In this case, the circular loop circuit and the figure-eight loop circuit form a closed circuit, and electrical connection is not required unlike a birdcage type RF coil. Therefore, as a detachable connecting member (connector), it is only necessary to connect both ends of the flexible substrate, and it is possible to use a magic fastener, so that connecting and releasing can be easily performed. (5) Although the RF coil of the above embodiment is mounted on the abdomen of the subject, the RF coil of the present invention can be applied to other imaging sites such as the hand, foot, knee, hip, and head of the subject. Can also be applied.

[0020]

According to the RF coil for a magnetic resonance diagnostic apparatus of the present invention, the shape of the RF coil is made stable, and the RF coil is mounted in close contact with the imaging part in a shape adapted to the shape of the imaging part of the subject. It is possible and easy to install. Further, since the shape regulating members are provided only at both peripheral ends or the center of the flexible substrate, the weight of the RF coil can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a state in which a connector of an RF coil of an embodiment is released and developed in a planar shape.

FIG. 2 is a cross-sectional view illustrating a layer structure of an RF coil according to an embodiment.

FIG. 3 is a perspective view showing a procedure for mounting (setting) the RF coil of the embodiment to a subject.

FIG. 4 is a partial cross-sectional view for explaining the operation of the shape regulating member in the connection state and the disengagement state of the connector of the RF coil of the embodiment.

FIG. 5 is a plan view showing a state where a conventional RF coil is not mounted.

FIG. 6 is a perspective view showing a state where a conventional RF coil is mounted.

FIG. 7 is an explanatory perspective view of a conventional RF coil shape stabilization method.

[Explanation of symbols]

1: Flexible board 2A, 2B: Loop circuit path 3: Loop connection circuit path 4: Capacitor element 5, 6: Short side 7a, 7b: Plug type connector 8a, 8b: Socket type connector 9:
Shape control member 10: Block 11: Cushion material

Claims (2)

[Claims] 1. An RF coil for a magnetic resonance diagnostic apparatus, comprising: a flexible board having a predetermined coil pattern; and a connecting member for removably connecting an end of the flexible board when the flexible board is curved into a cylindrical shape. It is provided that a shape regulating member that regulates a curved shape is provided at both peripheral ends or a central portion of the flexible substrate surface which is inside when both ends are connected by the connecting member and is curved into a cylindrical shape. An RF coil for a magnetic resonance diagnostic apparatus. 2. An R for a magnetic resonance diagnostic apparatus according to claim 1.
In the F coil, the coil pattern includes a pair of loop circuit electric paths provided at a peripheral end of a flexible substrate, and a plurality of loop circuits arranged in parallel at a predetermined interval so as to connect the pair of loop circuit electric paths. A connector for electrically connecting and disconnecting one end and the other end of the loop circuit electric circuit, wherein the connector comprises a loop coupling circuit electric circuit,
An RF coil for a magnetic resonance diagnostic apparatus, wherein the connector forms a birdcage RF coil in a connected state.