JPS63203147A - 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] [Object of the Invention] (Industrial Application Field) The present invention relates to magnetic resonance (MR)
The density distribution of a specific atomic nuclear spin in a specific cross section of a subject (living body) is calculated using the so-called Fn (CT) phenomenon.
CT a by edtofIlog+”apHy) method
Image (imaalna) L/, Magnetic Resonance Imaging System (a) where the MR11i is placed to diagnose the living body based on this image
In particular, the present invention relates to a magnetic resonance imaging apparatus with an improved configuration of signal detection means.

(Prior Art) An example of a conventional magnetic resonance imaging apparatus will be described with reference to FIG. At some point, in Figure 3,
A subject P is placed on a bed top (not shown), and this subject P is connected to the uniform magnetic field generating coil 1A.

1B and a gradient Vlii field generating coil 2 as main elements. Inside the main body, a gradient magnetic field from the gradient magnetic field generating coil 2 is superimposed on a uniform static magnetic field from the uniform If field generating coils IA and 1B to form a superimposed magnetic field, and the subject P is placed in this superimposed magnetic field. are doing. A surface coil 3 is placed on the subject P as a probe coil, and by applying an excitation rotating magnetic field with this surface coil 3, an MR phenomenon is caused in the subject P, and the induced MR signal is transferred to the surface coil. 1tyi at the position where the surface coil 3 of the subject P is applied by performing image area reconstruction processing using an image processing device (not shown) or the like.
Information such as layer images is obtained and images are displayed.

Here, the surface coil 3 used as a probe coil
is small and can be held by the operator, and
By applying the probe directly to the target area, it is possible to image external areas, so it is often used as a probe that can efficiently image small areas. However, since the surface coil 3 has a narrow field of view, it is difficult to position the subject, and when diagnosing long areas such as the spinal cord, it is necessary to repeatedly change the coil application position, which is inconvenient. Met.

(Problems to be Solved by the Invention) As described above, the conventional techniques attempt to efficiently image the small head area. In this case, it may be difficult to position the coil application position, or it may be necessary to change the coil application position again and again.
There were problems with diagnostic efficiency.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a magnetic resonance imaging apparatus capable of efficiently performing one-step imaging of a small area.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention distributes a subject placed on a bed in a uniform static magnetic field. By superimposing a gradient magnetic field and applying an excitation rotating magnetic field to the 11n field by a probe coil, an MR phenomenon is caused in the subject, the induced MR signal is detected by the probe coil, and 1i11Φ reconstruction processing is performed. By administering said he 1
! Person's picture iS! In a magnetic resonance imaging apparatus that obtains 1q of information, a plurality of probe coils that partially overlap each other and are electrically open are arranged on the top plate, and selection means for selecting one of the plurality of probe coils. , and tuning means for adjusting the tuning of the probe coil selected by the selection means.

(Function) According to such a configuration, when the subject is placed on the top plate, the selection means selects the probe coil at the position corresponding to the target region, and the same! By performing the i1 adjustment, it is possible to efficiently image a small area where the selected probe coil is installed, and by selecting another probe coil using the switching means, efficient imaging of other areas can be performed. You will be able to do things.

(Embodiment) A: Figs. 1 and 2 are circuit diagrams showing essential parts of an embodiment of a magnetic resonance imaging apparatus according to the present invention.

In FIGS. 1 and 2, three independent probe coils 5A, 5B are electrically open to the top plate 4.

5C partially overlap each other and select one of these three probe coils 5A, 5B, 5C 1
The configuration includes an I7J switching B6 and a tuner 7 that adjusts the tuning of the probe coil (5B in the figure) selectively switched by the switch 6 using a variable capacitor 7a, and leads to a signal processing system such as a transmitter/receiver etc. It is said that The probe coils 5A and 58.5G on the top plate 4 can be fixed in various ways such as buried, fixed with a stopper, fixed with adhesive, etc.
There is an audience.

According to such a configuration, when a subject who does not take oral communication is placed on the top plate 4, the IQ device C detects, for example, the probe coil 5B@ at a position corresponding to the target part of the subject.
By selecting and adjusting the tuning, it is possible to perform efficient decoy imaging of the small area where the selected probe coil 5B is installed.

Then switch 6 to switch to another probe coil (5A or 5A).
By selecting and synchronizing G>, efficient m-shadowing of other areas can be performed.

According to this embodiment as described above, the following effects are achieved.

■ According to this embodiment, since the coils 5A and 58.5C are arranged independently with their claws interlocked with each other, it is possible to continuously change the imaging region without the need to move the coil position or move the subject. This will improve diagnostic efficiency.

■ According to this embodiment, the coils (5A, 5B.

5C) are electrically open when not selected, so the selected coil (5A, 58゜one of 50)
It is possible to improve the accuracy of the signal without causing mutual interference.

■ According to this embodiment, the selected coil (5A).

5B and 5C), the signal can be highly accurate.

The present invention is not limited to the above embodiments, but can be implemented with various modifications without departing from the gist of the present invention.

[Effects of the Invention] As described above, the present invention provides a selection means for arranging a plurality of probe coils partially overlapping each other and electrically open on a top plate, and selecting one of the plurality of probe coils. and a tuning means for adjusting the tuning of the probe coil selected by the selection means, so that when the subject is placed on the top plate, the selection means can be used to adjust the tuning of the probe coil to the target area. Select the probe coil at the corresponding position and do the same:! By making the adjustment, it is possible to efficiently image the small area where the selected probe coil is installed, and by selecting another probe coil using the switching means, it is possible to efficiently image the other area. Accordingly, it is possible to provide a magnetic resonance imaging apparatus that can efficiently scan a small area.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams showing essential parts of an embodiment of a magnetic resonance imaging apparatus according to the present invention, and FIG. 3 is a diagram showing a conventional example. 4...Top plate, 5A, 58.5C...Coil, 6...
・Switcher, 7... Tuner. Applicant's representative Patent attorney Takehiko Suzue "Figure 1, Figure 2

Claims (2)

[Claims] (1) The subject placed on the bed top is placed in a uniform static magnetic field, a gradient magnetic field is superimposed, and an excitation rotating magnetic field is applied to the superimposed magnetic field by a probe coil. In a magnetic resonance imaging apparatus that generates an MR phenomenon, detects the induced MR signal with the probe coil, and performs image reconstruction processing to obtain image information of the subject, parts are arranged mutually on the top plate. Arrange multiple probe coils that overlap each other and are electrically open.
A magnetic resonance imaging apparatus comprising a selection means for selecting one of the plurality of probe coils, and a tuning means for adjusting the tuning of the probe coil selected by the selection means. (2) The magnetic resonance imaging apparatus according to claim 1, wherein a plurality of probe coils are embedded in a top plate.