Magnetic Resonance Imaging Apparatus

The present invention relates to a magnetic resonance imaging apparatus, and more specifically, to a magnetic resonance imaging apparatus with an improved mechanism for holding a transmitter-receiver coil.

When applying magnetic resonance to the diagnosis of a human disease, a subject is placed in a uniform magnetostatic field, a gradient magnetic field is superposed on the uniform magnetostatic field, and an exciting magnetic field is then applied to produce a magnetic resonance phenomenon. A magnetic resonance signal emitted from the subject is detected, and information concerning the projected area of the subject is obtained. Image information concerning at least one of the proton densities and relaxation time constants of the specific atomic nucleus of the subject can be obtained by subjecting the projected area information to image reconstruction processing. A diagnosis is made on the basis of this image information.

In a magnetic resonance imaging apparatus, a circular surface coil, used as a transmitter-receiver coil, is disposed on the surface of the subject. The exciting magnetic field is produced by the circular surface coil, and the magnetic resonance signal is also detected by the circular surface coil.

In order to dispose the circular surface coil on the surface of the subject, the circular surface coil is maintained on the subject by an adhesive tape or fastened by a band. Accordingly, preparing a diagnosis requires much time and effort, and the subject feels greatly inconvenienced by the attached coil. Moreover, it is very difficult to move the circular surface coil in three-dimensional space when using an adhesive tape or band.

The object of the present invention is to provide a magnetic resonance imaging apparatus having a transmitter-receiver coil capable of being easily moved and held in three-dimensional space.

According to an aspect of the present invention, there is provided a magnetic resonance imaging apparatus which applies an exciting magnetic field to a subject to produce a magnetic resonance phenomenon, detects a magnetic resonance signal received from the subject, and obtains information on the internal conditions of the subject on the basis of the received signal, comprising:

a coil for applying said exciting magnetic field and/or detecting said magnetic resonance signal received from said subject:

a holding member for holding said coil;

a plurality of flexible members for spatially disposing said coil through said holding member; and

a fixing member for fixing said coil through said holding member and said plurality of flexible members to a patient table.

In this magnetic resonance imaging apparatus, a transmitter-receiver coil is held by plurality of flexible members. Accordingly, the apparatus can maintain stiffness with the holding member, and an operator can easily move the transmitter-receiver coil.

FIG. 1 is a side view of a magnetic resonance imaging apparatus according to an embodiment of the present invention;

FIG. 2 is a front view of the apparatus of FIG. 1;

FIG. 3 is a local sectional view of a flexible member;

FIG. 4 is a unit sectional view of a flexible member.

FIGS. 1 through 3 show a magnetic resonance imaging apparatus according to one embodiment of the present invention. FIG. 1 is a side view of the present invention of a magnetic resonance imaging apparatus. A fixing member 2 is freely fitted to a patient table 1. a subject "a" is laid down on the patient table 1. The fixing member 2 is capable of moving along the longitudinal direction. A circular surface coil 3 produces a magnetic resonance phenomenon and detects a magnetic resonance signal received from the subject "a". The circular surface coil 3 is held by a holding member 10. Three flexible plastic pipes 4 are disposed between the holding member 10 and the fixing member 2. The head of the subject "a" rests on headrest 6. This headrest 6 is fitted on the patient table 1.

FIG. 2 is a front view of the apparatus of FIG. 1. The fixing member 2 is fitted on the outside of the patient table 1. On one side, the fixing member 2 is fixed to the patient table 1 with a screw 9. These screws 8, 9, are capable of manual adjustment. When screws 8, 9 are loosened, the fixing member 2 can be freely moved along the longitudinal direction to a different position. On the other hand, the circular surface coil 3 is fixed to the holding member 10 with a screw or pin 7.

FIG. 3 is a local sectional view of a flexible member. The flexible member is made of plurality of plastic pipes 5.

FIG. 4 is a unit sectional view of a flexible member. Moreover, spiral connecting pipes can be used as a flexible member.

As both holding member 10 and fixing member 2 are each fitted to the three flexible plastic pipes 4 at predetermined positions, the circular surface coil 3 is not subject to cantilever action.

In order to move the circular surface coil 3, each of the three flexible plastic pipes 4 is bent by hand. The three flexible plastic pipes 4 are easily bent without much effort. A condition for fixing the coil in three-dimensional space is fixing at least three points. As the fixing member 2 uses the three flexible member plastic pipes 4 to fix holding member 10, the surface coil 3 through the holding member 10 contains holding rigidity. Accordingly, the circular surface coil 3 is fixed in three-dimensional space at a position free of the object "a".

In the apparatus constructed in this manner, circular surface coil 3 is held by three flexible plastic pipes 4 and the apparatus can maintain the rigidity of the holding member, while still being easily moved. Moreover, as the fixing member 2 is capable of being moved along bed the scope of moving a circular surface coil 3 is increased.