JPH0994236A - Surface coil or receiving mr signal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface coil for receiving MR signal capable of readily giving access to all of the organs in an abdominal cavity and having a simple structure capable o obtaining MRI tomographic image of a desired region at high resolution. SOLUTION: This surface coil 1 for receiving MR signal is used by inserting in a human body and comprises a flexible non-magnetic sheet 2 having biocompatibility and a detecting coil 3 for detecting magnetic resonance signal having a given frequency emitted from the human body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface coil for MR signal reception arranged on or near the surface of a body part for detecting a nuclear magnetic resonance signal (MR signal) of a predetermined frequency from a human body.

[0002]

2. Description of the Related Art In recent years, nuclear magnetic resonance (hereinafter referred to as MR)
A minimally invasive method for diagnosing a human body using a phenomenon has been developed. The MR phenomenon refers to a phenomenon in which a certain atomic nucleus resonates and absorbs electromagnetic wave energy of a specific wavelength in a magnetic field, and then emits this as an electromagnetic wave. In an MR imaging (hereinafter referred to as MRI) apparatus using this MR phenomenon, The human body is placed in a static magnetic field, a high-frequency magnetic field of a predetermined frequency is applied to the human body to excite nuclei with spin in the human body, and the MR signal of a predetermined frequency generated while the excited nucleus returns to its original state is detected. Then, it is processed by a computer to obtain a tomographic image of the human body.

Generally, such an MRI apparatus has a single cylindrical magnet that covers almost the entire human body to generate a uniform static magnetic field, and a high-frequency magnetic field of a predetermined frequency to the human body placed in the static magnetic field. An RF coil for giving, an MR signal detecting coil for detecting an MR signal of a predetermined frequency emitted from an excited nucleus having a spin in the human body, and a control for processing a detection signal from the MR signal detecting coil to obtain a tomographic image of the human body Mainly composed of departments.

Recently, in order to reduce the burden on patients such as phobia of closure, an open type in which the above-mentioned single cylindrical magnet (closed type) that covers almost the entire human body is divided into two parts has become widespread. ing. This open type allows the doctor to directly approach the patient through the gap (space) between the two divided magnets, so that simultaneous treatment can be performed while observing the MR tomographic image in real time.

With the widespread use of the open type MRI apparatus capable of performing treatment through the gap (space) between the magnets, the combination of the surgical operation and the MRI apparatus has come to the spotlight. That is, an attempt has been made to perform a surgical operation on a patient from between the divided magnets of the MRI apparatus (US Pat. No. 53680).
No. 32).

Further, in the MRI apparatus, an MR signal detecting coil for detecting an MR signal of a predetermined frequency from a human body is incorporated in a magnet together with an RF coil.
There is a body surface coil (hereinafter, also referred to as a surface coil) in which a signal detection coil is attached to a living body surface such as an abdominal wall, which is provided separately from a magnet.

When the MR signal detecting coil is a surface coil, the MR signal detecting coil can be arranged in a region closer to the target region where MR imaging is desired, so that the resolution of the MR image is improved. Can
Very informative.

[0008] On the other hand, the area closer to the target area is M
Japanese Laid-Open Patent Publication No. 6-304152 and Japanese Laid-Open Patent Publication No. 6-31971 disclose an MR signal receiving coil provided in an insertion portion of an endoscope to be inserted into the body in order to arrange an R signal detecting coil.
No. 8 publication. Further, as an MR signal detecting coil that can approach the target site, a rectal coil including an MR signal detecting coil in an expandable and contractible bag is EP0385.
367A1. It is inserted into the intestine in a contracted state and is inflated into a balloon shape by a fluid at a desired site in the intestine or a desired site in the living body leading to the intestine. Further, there is also a sheet-shaped surgical drape that is attached to the body surface and is provided with an MR signal detection coil.

[0009]

Generally, in laparoscopic surgery, pneumoperitoneum is performed by filling a gas in the abdominal cavity to form a desired treatment space in the abdominal cavity. When such a laparoscopic surgery is performed on a patient from between the divided magnets of the MRI apparatus, a surface coil is attached to the outer surface of the abdominal wall of the patient as an MR signal detection coil in order to enhance the resolution. .

However, in the laparoscopic surgical operation in which the pneumoperitoneum is performed, the distance between the surface coil and the affected area to be actually MR imaged becomes large due to the presence of the large inflated abdominal cavity space. . That is,
Even if it is not, the surface coil that can only approach the affected area up to the surface of the abdominal wall further moves away from the affected area due to the presence of the pneumoperitoneum. Therefore, even if the surface coil is used to improve the resolution, the presence of the pneumoperitoneum causes the resolution to be inferior as compared with the case without pneumoperitoneum.

Further, the gap between the magnets in the open type MRI apparatus is only large enough for one operator to enter, and the distance between the magnets is fixed, so that the operator's work space and surgical operation are not required. Due to the limited installation space of the treatment instrument used, it may be difficult to place the surface coil at a desired site on the abdominal wall surface.

On the other hand, in the case where the MR signal detecting coil is provided in the insertion portion of the endoscope as described above, the MR signal detection coil is provided in the insertion portion of the endoscope where the target portion can be approached to some extent but the diameter reduction is desired. Since the size of the MR tomographic image is limited, the MR tomographic image in a desired range may not be obtained, or the target region may not be brought close to the target region as desired.

Further, the above-mentioned rectal coil requires a mechanical mechanism for expanding the rectal coil.
The structure becomes complicated. Further, since it is expanded in a narrow region of the lumen, its size is also limited, and only the luminal site or an organ communicating with the lumen can be accessed. In other words, it is not possible to directly access organs such as the liver-prone organs.

In addition, the sheet-shaped surgical drape has an M
Since the one provided with the R signal detection coil is attached to the body surface, it has the same problem as the body surface coil.
The present invention has been made in view of the above circumstances, and an object thereof is to obtain an MRI tomographic image in a desired range that allows easy access to all organs in the abdominal cavity and has a high resolution. An object of the present invention is to provide a surface coil for MR signal reception which has a simple structure.

[0015]

In order to solve the above-mentioned problems, the present invention is a flexible non-magnetic sheet which is inserted into the body and has biocompatibility, and is embedded in the sheet so that the human body can radiate. And a detection coil for detecting a nuclear magnetic resonance signal of a predetermined frequency.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment of the present invention. In FIG. 3, reference numeral 15 is a static magnetic field generating magnet of the open magnet type MRI apparatus. The magnet 15 is of a counter pole type and is composed of a pair of magnets 15a and 15b (15b not shown) facing each other, and is composed of a permanent magnet, a superconducting magnet, or a normal conducting magnet.

The magnet 15 is used for the bed 1 placed in a static magnetic field.
An RF coil that applies a high-frequency magnetic field of a predetermined frequency to the patient 20 on 8 and a gradient magnetic field generating coil that generates a minute gradient magnetic field for imparting spatial information to the MR signal are mounted on the casings of the magnets 15a and 15b. Prepared inside the body.

Reference numeral 1 in the figure denotes M for detecting an MR signal of a predetermined frequency emitted by an excited nucleus having a spin in the human body.
An MR signal receiving surface coil having an R signal detecting coil 3 (see FIG. 1), which is inserted into the abdominal cavity 12 by, for example, a trocar 10 as described later.

As shown in FIG. 1, the surface coil 1
Is made of a flexible mesh-like non-magnetic sheet 2 made of polypropylene.
The signal detection coil 3 is embedded. The MR signal detection coil 3 receives the MR from the detection coil 3 via the lead wire 4.
It is electrically connected to the MRI control circuit 17 that processes signals (see FIG. 3). The image signal processed by the MR control circuit 17 is sent to a monitor (not shown) and displayed as an MR tomographic image on this monitor.

In order to obtain an MRI tomographic image using the surface coil 1 having the above structure, first, as shown in FIG. 2, the sheet-shaped surface coil 1 is rolled in a tubular shape or folded. For example, the trocar 10 is introduced into the abdominal cavity 12 through the guide hole 19 of the trocar 10 inserted into the abdominal wall 11. Such work is performed through the gap 16 (see FIG. 3) between the magnets 15a and 15b of the static magnetic field generating magnets which are separated from each other.

After the surface coil 1 is introduced into the abdominal cavity 12, the surface coil 1 is unfolded and expanded by a gripping forceps or the like (not shown), and the surface coil 1 is placed at a desired position in the living body, preferably a target surface portion of the tissue X ( (See FIG. 3).

When the surface coil 1 is placed at a desired position in the unfolded state, a high frequency magnetic field of a predetermined frequency is applied by the RF coil to the patient 20 in the static magnetic field formed by the magnet 15 of the MRI apparatus. The generated MR signal from the human body is detected by the MR signal detection coil 3 of the surface coil 1 to obtain a tomographic image of the human body.

Next, the position of the affected part to be treated is determined by the obtained tomographic image, and a medical device 29 such as an endoscope or a treatment instrument introduced into the abdominal cavity 12 through the trocar 10 is approached toward the affected part position. Then, the affected area is treated. In this case, the treatment condition can be confirmed by looking at the MR image.

The surface coil 1 may be directly introduced into the abdominal cavity 12 through the incision formed in the abdominal wall 11 without the trocar 10. As described above, the surface coil 1 according to the present embodiment is formed of a flexible material, can be deformed, and can be deployed thereafter. Therefore, the conventional surface coil attached to the outer surface of the body wall can be used. Unlike a coil, it can be introduced into a body cavity through a channel or trocar of an endoscope. That is, the MR signal detection coil 3 can be brought as close as possible to the living body part to be MR-imaged, and therefore the resolution of the MR image can be increased.
Safe and reliable surgery can be performed. as a result,
The operation time can be shortened, and the cost of the entire operation can be reduced. These characteristics are particularly useful in confirming the blood vessel running and bile duct during laparoscopic cholecystectomy, confirming the position of stones, and determining the resection range in laparoscopic gastrectomy or hepatectomy. Moreover, since a mechanical mechanism is not required to deploy the MR signal detection coil, the handling is easy.

Further, the surface coil 1 of this embodiment
Since it is possible to easily access any part of the body through the abdominal wall by deforming, like the rectal coil introduced into the body through the lumen or the detection coil provided at the insertion part of the endoscope, There is no restriction on its size. Therefore, an MRI tomographic image in a desired range can be obtained with a large area.

FIG. 4 shows a second embodiment of the present invention. The MR signal receiving surface coil 1a of the present embodiment is made of a plastic sheet 2a, and the MR signal detecting coil 3 is embedded in the sheet 2a. The other configuration is the same as that of the first embodiment.

FIG. 5 shows a third embodiment of the present invention. The MR signal receiving surface coil 1b of the present embodiment has a hole 30 provided at the center of the mesh sheet 2 of the surface coil shown in the first embodiment. The other configuration is the same as that of the first embodiment. With such a configuration, the treatment tool or the like can be approached to the affected area through the hole 30, so that the treatment work becomes extremely easy.

[0028]

As described above, the surface coil for MR signal reception of the present invention is formed of a flexible material and can be deformed, and further, it can be deployed thereafter, so that it can be deployed outside the body wall. Unlike a conventional surface coil attached to the surface, it can be introduced into the body cavity through a channel or trocar of an endoscope.
That is, the MR signal detection coil can be brought as close as possible to the living body part to be MR imaged. Therefore, the resolution of the MR image can be increased, and safe and reliable surgery can be performed. In addition, since no mechanical mechanism is required for unfolding, handling is easy.

Further, since the surface coil of the present invention can easily access any part of the body through the abdominal wall or the like by being deformed, the rectal coil introduced into the body through the lumen or the insertion part of the endoscope. The size of the detection coil is not limited, unlike the detection coil provided in the. Therefore, an MRI tomographic image in a desired range can be obtained with a large area.

[Brief description of drawings]

FIG. 1 is an overall view of a surface coil according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of use of the surface coil of FIG.

[Fig. 3] Insert the surface coil of Fig. 1 into the abdominal cavity and
It is a figure which shows a mode that R laparoscopic surgery is performed.

FIG. 4 is an overall view of a surface coil according to a second embodiment of the present invention.

FIG. 5 is an overall view of a surface coil according to a third embodiment of the present invention.

[Explanation of symbols]

1, 1a, 1b ... MR signal receiving surface coil, 2
… Sheet, 3… Detection coil.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Takahashi 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (72) Ryoji Masuchibuchi 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd. (72) Inventor Katsuya Suzuki 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd.

Claims (1)

[Claims] 1. A flexible non-magnetic sheet having biocompatibility, which is inserted into a body, and a detection coil which is embedded in the sheet and detects a nuclear magnetic resonance signal of a predetermined frequency emitted by a human body. A surface coil for MR signal reception, comprising: