JPS63181751A - Magnetic resonance imaging apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION (Industrial Field of Application) The present invention relates to a magnetic resonance imaging apparatus (hereinafter referred to as an MRI apparatus) that obtains a magnetic resonance image of a subject.

(Prior Art) In an MRI apparatus, dedicated coils are used for a transmitting coil that transmits RF pulses to a subject and a receiving coil that receives an MR multiplied signal from the subject. (referred to as the cross-coil method), the induction that flows in the transmitting coil when the magnetic fields that are formed when current flows through the transmitting coil and the receiving coil are the same, or when there is coupling due to mutual induction. Since the current creates a magnetic field in the opposite direction, the level of the signal received by the receiving coil decreases. Therefore, in order to prevent this, in the cross-coil method, the transmitting coil and the receiving coil are generally arranged so as to be spatially orthogonal to each other. In fact, in existing saddle-type coils (transmission/reception coils), the transmission and reception coils are arranged orthogonally to each other.

(Problems to be Solved by the Invention) However, when using a surface fill (also referred to as a surface coil), since the surface coil is placed on the desired surface of the subject, There is a drawback that the orthogonal relationship with the transmitting and receiving coils is not satisfied and the reception level decreases.

SUMMARY OF THE INVENTION The present invention aims to eliminate the above-mentioned drawbacks, and its purpose is to provide an MR signal that can efficiently receive MR multiplied signals regardless of the location of the surface coil.
The objective is to provide an I-device.

[Structure of the Invention] (Means for Solving the Problems) The present invention is configured to be rotatably supported around the body axis of a subject, and transmit RF pulses in a spatially orthogonal arrangement relationship with a surface coil. It is equipped with a transmitting coil that can be used.

(Function) According to the transmitting coil, the direction of the coil can be adjusted so as to be spatially orthogonal to the surface coil regardless of where the surface coil is placed, thereby efficiently receiving the MR multiplied signal. be able to.

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

FIGS. 1(a) and 1(b) show an embodiment of the present invention.

In FIG. 1(a), reference numeral 3 denotes a pedestal, and within this pedestal 3, the transmitting coil 1 is placed. This transmitting coil 1
is wound around a cylindrical bobbin 5 extending perpendicularly to the plane of the paper, and is used to transmit RF pulses. A subject (not shown) placed on the bed top is placed within the cylindrical bobbin 5 (inside the photographing hole 4), and the body axis of the subject is perpendicular to the paper surface. The cylindrical bobbin 5 is supported by the pedestal 3 so as to be rotatable about the body axis of the subject.

Reference numeral 2 denotes a surface coil disposed on the desired surface of the subject, which receives the MR multiplied signal from the subject.

FIG. 1(b) is an enlarged sectional view taken along the line AA' in FIG. 1(a). As shown in the figure, a stopper 21 is provided on the outer peripheral surface of the end portion of the bobbin 5, and this stopper 21 is engaged with an annular groove 22 of an internal structure 20 in the pedestal 3.

By doing this, the positional shift of the bobbin 5 during rotation is prevented.

Further, by using a material with a small coefficient of friction for the stopper 21, smooth rotation of the bobbin 5 is achieved.

In the above configuration, when the direction of the surface coil 2 placed on the desired surface of the subject is in the direction of arrow 6,
In FIG. 1(a), the direction of the transmitting coil 1 is indicated by the arrow 7.
Since both coils are spatially orthogonal to each other, it is possible to efficiently receive MR multiplied signals from the subject.

Further, when the surface coil 2 is arranged as shown in FIG. 2, the direction of the surface coil 2 is indicated by the arrow 8.
Therefore, in the direction of the transmitting coil 1 (direction of arrow 7) shown in FIG. 1(a), the MR multiplied signal cannot be efficiently received.

Therefore, the transmitting coil 1 is rotated in the direction of arrow 9 as shown in FIG. 2, and the transmitting coil 1 is oriented in the direction of arrow 10. As a result, both coils are spatially orthogonal, and MR multiplied signals can be received efficiently.

Furthermore, even when the surface coil 2 is arranged as shown in FIG. 3, by rotating the transmitting coil 1 in the same manner as above, the transmitting coil 1 and the surface coil 2 can be made orthogonal to each other. Can receive MR signals more efficiently.

In this embodiment, the direction of the coil can be adjusted by rotating the transmitting coil 1, and by this adjustment, the transmitting coil 1 and the surface coil 2 can be adjusted regardless of where the surface coil 2 is placed. can be made orthogonal to each other, and the MR multiplied signal can be received more efficiently.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide an MRL device that can efficiently receive an MR multiplied signal regardless of where the surface coil is placed.

[Brief explanation of the drawing]

FIG. 1(a) is an explanatory diagram showing one embodiment of the present invention, FIG. 1(b) is an enlarged sectional view taken along line AA' in FIG. 1(a), and FIGS. FIG. 1... Transmission coil, 2... Surface coil,
3... Frame, 4... Photographing hole, 20... Frame internal structure. Agent Patent Attorney Nori Chika Ken Shu
Norio Ogo Figure 1

Claims (1)

[Claims] An RF pulse is transmitted to the subject, a magnetic resonance signal from the subject is detected by a SurfEight coil placed on the desired surface of the subject, and the magnetic resonance signal of the subject is detected based on the detected magnetic resonance signal. A magnetic resonance imaging apparatus that forms a resonance image, comprising a transmission coil that is rotatably supported around the body axis of the subject and that is capable of transmitting RF pulses in a spatially orthogonal arrangement with the surface coil. A magnetic resonance imaging device featuring: