JP3214746B2 - Magnetic resonance imaging equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving coil used in a magnetic resonance imaging apparatus for imaging a subject, and more particularly to an improved apparatus for a surface coil.

[0002]

2. Description of the Related Art The nuclear magnetic resonance phenomenon is a phenomenon in which a nucleus having a non-zero spin and a magnetic moment placed in a static magnetic field resonates and absorbs only a specific electromagnetic wave.
This atomic nucleus has an angular frequency ω ₀ (ω ₀ = 2πν)
₀ , ν ₀ ; Larmor frequency). ω ₀ = γ · H ₀ where γ is the gyromagnetic ratio specific to the type of nucleus,
H ₀ is the static magnetic field strength.

An apparatus for performing a living body diagnosis using the above principle receives an electromagnetic wave of the same frequency induced after the above-described resonance absorption by a receiving coil and processes the signal to obtain a nuclear density and a longitudinal relaxation time T. ₁ , diagnostic information reflecting information such as the lateral relaxation time T ₂ , flow, and chemical shift, for example, a slice image of a subject, etc., is obtained in a non-invasive manner.

The collection of diagnostic information by nuclear magnetic resonance can excite all parts of a subject placed in a static magnetic field and collect signals. Due to clinical demands for imaging, an actual apparatus is designed to excite a specific site and collect its signal.

In this case, the specific portion to be imaged is generally a slice portion having a certain thickness, and an echo signal or FI from this slice portion is generally used.
Nuclear magnetic resonance signals (NMR signals) of D signals are collected by executing a number of data encoding processes, and these data groups are subjected to image reconstruction processing by, for example, a two-dimensional Fourier transform method, thereby obtaining the specific slice portion. An image is generated.

[0006] In imaging of a spine or the like by such a magnetic resonance imaging apparatus, a flat surface coil is used as a receiving coil. Conventionally, a receiving coil having a single coil element has been used. However, in recent years, a coil having a plurality of coil elements and using them in combination has been developed. For example, as shown in FIG. 3, it is formed by winding coils 2a, 2b and 2c around a large winding frame 1, respectively.

[0007]

However, in this type of conventional receiving coil device, since it is necessary to cut a large winding material and attach the coil, it is difficult to manufacture the receiving coil device. In addition, there is no waste due to the repetitive processing of similar shapes. Further, when the receiving coil breaks down, the entire unit (large winding frame) must be replaced, which is uneconomical.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a receiving coil which can be manufactured easily, can achieve cost reduction, and can improve the efficiency of replacement even in the case of failure. An object of the present invention is to provide a magnetic resonance imaging apparatus using the same.

[0009]

In order to achieve the above object, according to the present invention, the structure of a magnetic resonance imaging apparatus is made as follows, thereby facilitating the manufacture of a receiving coil and reducing the cost. . That is, in a magnetic resonance imaging apparatus having a means for irradiating a subject with an electromagnetic wave in a static magnetic field and a receiving coil as a means for detecting a response to the electromagnetic wave, one or more coils are used as the receiving coil. It is characterized in that it is assembled into one block, a plurality of these blocks are prepared, these are mechanically connected, and the coils are electrically connected to each other, so that a larger coil can be used.

In a magnetic resonance imaging apparatus having means for irradiating a subject with an electromagnetic wave in a static magnetic field and a receiving coil as means for detecting a response to the electromagnetic wave, one or more of the receiving coils may be used as the receiving coil. Is assembled into one block, a plurality of these blocks are prepared, and these are each mechanically connected to one base, and the coils are electrically connected to each other, so that a larger coil can be used. It is characterized by doing so. In these magnetic resonance imaging apparatuses, an adjustment substrate is provided in each block, and a coil is connected to the adjustment substrate.

[0011]

According to the above construction, one or a plurality of coils are assembled into one block and a plurality of these blocks are prepared and these are mechanically connected to each other, or each is mechanically connected to one base. Since the receiving coil is formed so as to be connected, a similar-shaped component can be manufactured by molding, and the cost can be reduced. In addition, since an adjustment board is provided in each block and a coil is connected to the adjustment board, it is possible to efficiently receive NMR signals.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the receiving coil of the magnetic resonance imaging apparatus according to the present invention. 1A shows an example of a coil element, FIG. 1B shows an example in which a plurality of coil elements are mechanically connected, and FIG. 1C shows an example in which the coil elements are mechanically connected and fixed. It is.

In FIG. 1A, a conductive coil 2
Is mounted on a non-magnetic, non-conductive and industrially workable block 3 such as plastic, for example, and is also connected to an adjustment substrate 4 provided on the block 3. One coil element is formed by the coil 2, the block 3, and the adjustment substrate 4. The coil 2 may be attached to the block 3 a plurality of turns, but in this embodiment it is one turn. The resonance frequency changes depending on the strength of the magnetic field, and the inductance of the coil changes accordingly. Therefore, the resonance frequency need not be one turn as long as the resonance frequency is matched. The adjustment substrate 4 includes
For example, electric elements such as a preamplifier and a tuning circuit are formed to make it easy to receive an NMR signal. The block 3 is manufactured by molding into a shape that maintains sufficient strength even when a plurality of coil elements are mechanically connected. Although three coil elements are shown in the figure, they are connected to form one large receiving coil (surface coil) as shown in FIG. In this case, electrical connection is made by connecting the adjustment substrates 4 with the cables 5. The outputs from the coil elements connected by these cables 5 are connected to a receiver connected to a computer on the housing side. The number of coil elements to be connected depends on the use mode, but when used for imaging of the spine or the like, about six coil elements are used. FIG. 1C shows an example in which the coil elements are mechanically connected and fixed, and the side portions of the block 3 are fixed using bolts 6 and nuts 7 at a plurality of locations.

The coil formed in this manner is used as a receiving coil as a means for detecting a response to a means for irradiating the subject with electromagnetic waves in a static magnetic field formed in a gantry, for example. Note that there is also a method of using a connector or connecting the boards without using the cable 5 for the connection between the adjustment boards 4.

FIG. 2 shows a second embodiment of the receiving coil of the magnetic resonance imaging apparatus according to the present invention. As shown in FIG. 2B, a coil element as shown in FIG. This is an example of a case where the coil elements are mechanically connected and fixed. In FIG. 2A, the coil 2 and the adjustment substrate 4 are the same as those in the example shown in FIG. 1 except that the shape of the block 3 is different, and protrusions 3a and 3b are formed at front and rear ends. When these coil elements are mechanically connected and fixed, as shown in FIG. 2B, holes 9a and 9b are provided on one base 8 at positions corresponding to the protrusions 3a and 3b, respectively. Then, the protrusions 3a and 3b of the block are inserted into these holes 9a and 9b and fixed by being inserted. With such a fixing method, the overall strength can be maintained by the strength of the base 8 after the block 3 is assembled, even if the block 3 is somewhat soft and has insufficient mechanical strength. The electrical connection of these coil elements is made by connecting the adjustment substrates 4 with cables 5 as in the embodiment of FIG. 1, and the output of the receiving coil is also connected to the receiver. There is also a method of using a connector or connecting the substrates without using the cable 5 for the connection between the adjustment substrates 4.

The shape of the block 3 is not limited to those shown in FIGS. 1 and 2, but can be appropriately modified so as to be mechanically strong and convenient for mechanically connecting and fixing. It is.

[0017]

As described above, according to the present invention, one or a plurality of coils are assembled into one block, and a plurality of these blocks are prepared and these are mechanically connected to each other. Since the receiving coil is made so as to be mechanically connected to the base, a similar shaped part can be manufactured by performing molding, so that there is a merit of a so-called manufacturing number and a cost reduction can be achieved. it can. Further, since the coil can be manufactured by molding, the manufacturing time is shortened and the structure of the coil is simplified. Further, when the coil has failed, for example, only the failed coil element needs to be replaced, so that there is an effect that the efficiency is improved and the economy is improved.

[Brief description of the drawings]

FIG. 1 is an embodiment of a receiving coil of a magnetic resonance imaging apparatus according to the present invention.

FIG. 2 is another embodiment of the receiving coil of the magnetic resonance imaging apparatus of the present invention.

FIG. 3 is a diagram for explaining a conventional technique.

[Explanation of symbols]

 Reference Signs List 1 reel 2 coil 3 block 4 adjustment board 5 cable 6 bolt 7 nut 8 base 9 hole

Claims (3)

(57) [Claims] 1. A magnetic resonance imaging apparatus comprising: means for irradiating a subject with an electromagnetic wave in a static magnetic field; and a receiving coil as means for detecting a response to the electromagnetic wave. Is assembled into one block, a plurality of these blocks are prepared, and these blocks are mechanically connected, and the coils are electrically connected, so that a larger coil can be used. Magnetic resonance imaging apparatus. 2. A magnetic resonance imaging apparatus comprising: means for irradiating a subject with an electromagnetic wave in a static magnetic field; and a receiving coil as a means for detecting a response to the electromagnetic wave. Is assembled into one block, a plurality of these blocks are prepared, and these are each mechanically connected to one base, and the coils are electrically connected to each other, so that a larger coil can be used. A magnetic resonance imaging apparatus characterized in that: 3. The magnetic resonance imaging apparatus according to claim 1, wherein an adjustment substrate is provided in each block, and a coil is connected to the adjustment substrate.