JPH042643Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Technical field of the invention] This invention uses magnetic resonance (MR:
The present invention relates to a magnetic resonance imaging device (hereinafter also referred to as an MR imaging device) that uses the phenomenon of magnetic resonance (hereinafter referred to as “MR”) to image information based on the density distribution of specific atomic nuclear spins in a specific cross section of an object.

[Technical background of the invention and its problems]

For example, in a diagnostic MR imaging device, in order to obtain a tomographic image of a specific position of the subject, a very uniform static magnetic field Ho along the Z-axis direction is applied to the subject P as shown in Fig. 3, and a pair of A linear magnetic field gradient is added to the static magnetic field Ho by the gradient magnetic field coils 1A and 1B. A specific atomic nucleus resonates with the static magnetic field Ho at a nuclear frequency Wo expressed by the following equation.

Wo=γ・Ho...(1) In equation (1), γ is the gyromagnetic ratio, which is unique to the type of atomic nucleus. A rotating magnetic field H1 at a nuclear frequency Wo that makes only a specific atomic nucleus resonate is applied to the subject P through a pair of transmitting coils 2A and 2B within the illustrated XY plane set using the linear magnetic field gradient, The MR phenomenon is caused only in a specific slice portion S (which is a planar portion but actually has a certain thickness) from which a tomographic image is obtained.
The MR phenomenon is observed as a free induction decay (FID) signal (hereinafter referred to as "FID signal") via a pair of receiving coils 3A and 3B, and by Fourier transforming this signal, the spin of a specific atomic nucleus is detected. A single spectrum for rotation frequency is obtained. In order to obtain a tomographic image as a CT image, projection images of the slice portion S in multiple directions within the XY plane are required. For this purpose, after exciting the slice portion S and causing the MR phenomenon,
As shown in Fig. 4, when a linear magnetic field gradient Gxy having a linear gradient in the X'-axis direction (coordinate system rotated by θ° from the X-axis) is applied to the magnetic field Ho, the The magnetic field line E is a straight line, and the rotational frequency of a specific nuclear spin on that line is expressed by the following equation. Here, for convenience of explanation, signals D1 to _{D o (} a kind of FID
signal). The amplitudes of the signals D1 to D _o correspond to isomagnetic field lines E1 to E _o that pass through the slice portion S, respectively.
It is proportional to the nuclear spin density above. However, the FID signal that is actually observed is the sum of all D1 to D _o (i.e., composite FID signal)
Therefore, by Fourier transforming this FID signal, projection information (one-dimensional image) PD of the slice portion S onto the X' axis can be obtained. This X' axis is x-y
By rotating within the plane, projection information in each direction within the xy plane can be obtained in the same manner as described above, and a CT image can be synthesized based on this information.

FIG. 5 is a perspective view showing the relationship between a receiving coil unit and a bed in a conventional MR imaging apparatus, and FIG. 6 is a sectional view taken along line Ao-A in FIG. In FIGS. 5 and 6, reference numeral 3 denotes a receiving coil unit including the pair of receiving coils 3A and 3B;
A is a bed on which the subject P (not shown in FIG. 5) is placed, and 4B is a mat placed on the bed 4A.

By the way, as shown in FIG. 6, when the subject P is placed on the bed 4A via the mat 4B and the subject P is surrounded by the receiving coil unit 3,
There is a problem in that the curved opposing end B of the receiving coil unit 3 gets wedged into the back surface of the subject P, causing pain to the subject P.

Further, when positioning (positioning) the receiving coil unit 3 in this state, the subject P must be lifted once, which poses a problem of poor operability.

Furthermore, the reception level of the MR signal from the subject part near the gap C of the curved opposing end B of the receiving coil unit 3 is particularly weak, and as a result, the uniformity of the visualized MR image deteriorates and the resolution decreases. This is causing an inconvenience.

[Purpose of invention]

The present invention was developed in view of the above circumstances, and its purpose is to provide a receiving coil unit that does not cause pain to the subject when attached, and that has excellent operability.
Another object of the present invention is to provide a magnetic resonance imaging apparatus that can visualize MR images with excellent resolution.

[Summary of the idea]

The configuration of the present invention to achieve the above object includes a bed on which a subject is placed, a bed having an open end and curved to surround the subject placed on the bed,
A receiving coil unit is provided to be detachably and slidably attached to the bed, and the receiving coil unit detects a magnetic resonance signal induced in the subject by a magnetic resonance phenomenon, and the detected magnetic resonance signal is detected by the receiving coil unit. In a magnetic resonance imaging apparatus that visualizes a magnetic resonance image of the subject based on resonance signals, a predetermined gap is maintained between the subject and an inner surface of a receiving coil unit placed on the bed and surrounding the subject. The present invention is characterized in that it has a support member that supports the subject to be examined and holds the open end of the receiving coil unit with a side surface along the longitudinal direction.

[Example of idea]

Hereinafter, the present invention will be specifically explained with reference to Examples.

FIG. 1 is a perspective view showing the relationship between a receiving coil unit and a bed in a magnetic resonance imaging apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line DoD in FIG.

Note that the subject P is omitted in FIG. 1.

The difference between the device according to the present invention and the conventional device is that
This is because the support member 6 is provided.

This support member 6 is a first mat member 6A that is placed on the bed 4A and supports the subject P through a gap between the curved opposing ends B of the receiving coil unit 3.
and a curved opposing end B of the receiving coil unit 3.
second mat members 6B, 6C attached to the inner surface of the test subject P and supporting the subject P, and third mat members 6D, 6E, 6F, 6G distributed along the first mat member 6A. It consists of

By configuring the support member 6 in this way,
Subject P surrounded by receiving coil unit 3
As is clear from FIG. 2, the receiving coil unit 3 is disposed approximately at the center within the receiving coil unit 3 without coming into contact with the curved opposing end B of the receiving coil unit 3. Therefore, it is possible to image the subject P without causing pain to the subject P, and,
Since the region of low sensitivity between the curved opposing ends B of the receiving coil unit 3 is outside the first mat member 6A, that is, outside the subject P,
MR signals can be detected uniformly, and as a result, the MR of the subject P visualized based on the MR signals
The image will have excellent resolution.

Further, most of the body weight of the subject P is applied to the first mat member 6A, and the second mat members 6B, 6C and the third mat members 6D, 6E, 6F, 6G maintain the stability of the subject P. It plays a supporting role. Therefore, in order to position the receiving coil unit 3, move the receiving coil unit 3 along the arrow
direction (body axis direction of the subject P), place the receiving coil unit 3 on the bed 4A together with the third mat members 6D, 6E, 6F, and 6G while the receiving coil unit 3 is still attached. It is only necessary to slide, and there is no need to lift the subject P at this time.

Furthermore, if the total thickness t1 of the receiving coil unit 3 and the second mat member 6B or 6C is made slightly thinner than the thickness t2 of the first mat member 6A,
With the subject P lying on the bed 4A, the receiving coil unit 3 can be attached and detached freely.

It should be noted that the components other than the support member 6 are the same as those of the prior art, so the explanation thereof will be omitted.

In this way, in the device of this embodiment, the subject P
The inner surface of the receiving coil unit 3 surrounding the subject P
Since the receiving coil unit 3 is constructed with a support member 6 that supports the subject P to maintain a predetermined gap between the receiving coil unit 3 and The receiver coil unit 3 has excellent operability and an MR with excellent resolution.
It becomes possible to visualize the image. In particular, the support member 6 is connected to the first mat member 6A, the second mat member 6B, 6C, and the third mat member 6D, 6.
E, 6F, and 6G, the stability of the subject P placed on the bed 4A and the ease of attaching and detaching the receiving coil unit 3 can be achieved.

One embodiment of the present invention has been described above, but
The present invention is not limited to the above embodiments,
It goes without saying that modifications can be made as appropriate within the scope of the gist of the present invention.

For example, in the above embodiment, as the support member 6,
First mat member 6A, second mat member 6B,
6C, third mat member 6D, 6E, 6F, 6G
Although the explanation has been given on the one having only the first mat member 6A or the first mat member 6A,
The support member 6 may include the mat member A and the second mat members 6B and 6C. Even with this configuration, although the stability of the subject P is slightly inferior to the above embodiment, the object of the present invention can be fully achieved.

In addition, the first mat member 6A, the second mat member 6B, 6C, and the third mat member 6D, 6E, 6
It goes without saying that F and 6G may be made of any material as long as it has appropriate flexibility.

Note that the support member 6 is not limited to a mat member, and any member can be used as long as it supports the subject so as to maintain a predetermined distance between the receiving coil unit 3 and the subject.

[Effect of idea]

As described in detail above, according to the present invention, the receiving coil unit does not cause pain to the subject when it is attached, the receiving coil unit has excellent operability, and furthermore, MR signals from the subject can be detected. By making the state spatially uniform, it is possible to provide a magnetic resonance imaging apparatus that can visualize MR images with excellent resolution. Moreover,
The coil unit can be attached to and removed from the subject from above, and it can also be slid freely in the body axis direction of the subject, which has the unique effect of facilitating positioning.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the relationship between a receiving coil unit and a bed in a magnetic resonance imaging apparatus according to an embodiment of the present invention, Fig. 2 is a sectional view taken along line Do-D in Fig. 1, and Fig. 3 is a magnetic resonance imaging apparatus. 4 is a diagram of the principle of obtaining projection information by magnetic resonance phenomenon, FIG. 5 is a perspective view showing the relationship between the receiving coil unit and the bed in a conventional magnetic resonance imaging apparatus, and FIG. It is a sectional view taken along the line Ao-A. 3...Receiving coil unit, 4A...Bed, 6
...Supporting member, 6A...First mat member, 6
B, 6D...Second mat member, 6D, 6E, 6
F, 6G... Third mat member, B... Curved opposing end, P... Subject.

Claims (1)

[Claims for Utility Model Registration] (1) A bed on which a subject is placed; and a bed having an open end, curved to surround the subject placed on the bed, and being detachable from the bed. a receiving coil unit that is slidably provided, the receiving coil unit detects a magnetic resonance signal induced in the subject by a magnetic resonance phenomenon, and the receiving coil unit detects a magnetic resonance signal induced in the subject based on the detected magnetic resonance signal. In a magnetic resonance imaging apparatus for visualizing a magnetic resonance image of a subject, the subject is supported so as to maintain a predetermined gap between the inner surface of a receiving coil unit placed on the bed and surrounding the subject and the subject. , and a support member that holds the open end of the receiving coil unit on a side surface along the longitudinal direction. (2) The magnetic resonance imaging apparatus according to claim 1, wherein the support member is a mat member.