JP2915466B2 - Detection coil for magnetic resonance imaging - Google Patents

Description

The present invention relates to a detection coil for magnetic resonance imaging, and more particularly to an improvement in the coil structure.

(Prior Art) As is well known, a detection coil such as a surface coil is disposed close to or close to a specific site to be imaged by magnetic resonance imaging, and a magnetic resonance signal (hereinafter, referred to as hydrogen atom) excited at the specific site. It is used in a magnetic resonance imaging apparatus to detect the “MR signal”.

Such surface coils have various sizes depending on the purpose of diagnosis and the site, and are effective for precise diagnosis of the spine and spinal cord.

In general, a magnetic resonance imaging apparatus applies a rotating magnetic field for excitation and a gradient magnetic field to a subject under a static magnetic field, detects an MR signal excited at a specific portion of the subject by a surface coil or the like, and collects data. An image is reconstructed based on the acquired data and a reconstructed image (hereinafter, referred to as “MRI image”) is displayed on a monitor.

By the way, medical institutions such as hospitals often use endoscopy as a method for obtaining a diagnostic image of a patient. In this endoscopic examination, a guide portion of an endoscope is inserted into a body cavity of a subject, and an esophageal wall, a stomach wall, and an intestinal wall are diagnosed optically or ultrasonically. However, since it is impossible to see hydrogen atoms in body tissue as in magnetic resonance imaging, even if ultrasound imaging of body tissue is performed, resolution cannot be denied.

Therefore, recently, attempts have been made to take advantage of the characteristics of the above-described surface coil to take an image of the inside of a body cavity with a magnetic resonance imaging apparatus in parallel with the inspection or treatment using an endoscope.

(Problems to be solved by the invention) However, when feeding a surface coil into a body cavity,
Although it is considered most useful to use the forceps channel of the endoscope, the diameter of the forceps channel is, for example, about 2.8 mm, whereas the surface coil is significantly larger in size and shape than the diameter. However, there has been a problem that the forceps channel of the endoscope cannot be actually used. Note that, when the forceps channel of the endoscope is fed into a body cavity through a surface coil having a conventional structure, the shape of the surface coil is distorted, which is not suitable for detecting an MR signal.

The present invention has been made in view of the above circumstances, and an object of the present invention is to be able to feed into a body cavity through a forceps channel of an endoscope and to correctly detect an MR signal in the body cavity. An object of the present invention is to provide a detection coil for magnetic resonance imaging.

[Constitution of the Invention] (Means for Solving the Problems) The first invention of the present application is formed into a shape which can be linearly contracted and deformed by cooling to pass through a forceps channel of an endoscope, and is heated by a temperature in a body cavity. The present invention is characterized in that it is a shape memory alloy structure for restoring to an original memory shape suitable for detecting a magnetic resonance signal. Also, the second invention of the present application is to maintain a shape that is reduced and deformed at a temperature different from the body cavity temperature and can pass through a narrow opening, and restores a shape suitable for detecting a magnetic resonance signal at the body cavity temperature. It is a feature.

(Operation) With the configuration of the detection coil for magnetic resonance imaging according to the present invention, it can be sent into a body cavity through a forceps channel of an endoscope, for example, by being reduced in size, and sent into the body cavity, for example, depending on the temperature in the body cavity. The shape is restored to a size suitable for detecting the MR signal.

(Embodiment) FIG. 1 is a configuration diagram schematically showing a surface coil according to an embodiment to which the present invention is applied. FIG.
FIG. 2B shows the reduced shape.

The surface coil 1 of this embodiment is formed integrally with the lead wire 2 and has a single circular coil shape as shown in FIG. 1A at a high temperature such as 300 ° C. to 600 ° C. It has a stored shape memory alloy structure, and when air-cooled or water-cooled, it is reduced and deformed linearly as shown in FIG. Then, at the time of the linear contraction deformation as shown in FIG. 2B, the forceps channel 4 of the endoscope 3 as shown in FIG.
Can be sent into the body cavity through the body, and sent into the body cavity and placed under the body cavity temperature (about 37 ° C to 40 ° C)
The original memory shape 1a having a size suitable for detecting the MR signal is restored to the memory shape shown in FIG. 1 (A).

In FIG. 2, the image processing unit 5 receives the signal indicating the subject from the endoscope 3 and performs a process of obtaining an endoscope image in the body cavity, and displays the endoscope image obtained by this process on the display. 6 is displayed. Thereby, it is possible to recognize which part in the body cavity the surface coil 1 should be arranged close to or close to.

Since the surface coil 1 of the present embodiment is a shape memory alloy structure as described above, it can be easily fed into the body cavity through the forceps channel of the endoscope, and can be inserted into the body cavity.
MR signals can be detected correctly. Then, after the examination by the magnetic resonance imaging, when the surface coil 1 is removed from the body cavity, it may be performed in the same manner as the removal of a normal forceps or a snare.

Next, an outline of a case where imaging by magnetic resonance imaging is performed using the surface coil 1 of the present embodiment will be described with reference to FIG.

After inserting the subject P, in which the surface coil 1 is disposed at a specific site in the body cavity, into the imaging space of the main magnet 7, the X-axis, Y-axis, and Z-axis are generated by the gradient coil 8 under a static magnetic field generated by the main magnet 7. Is applied to the subject P at the same time as the surface coil 1
A rotating magnetic field for excitation is further applied, and an MR signal excited at a specific site in the body cavity of the subject P is detected by the surface coil 1 and received by the transceiver 9, and the MR signal is collected by the computer system 10 and imaged. Display the reconstructed MRI image on display 1
Monitor display on 1.

As described above, when the surface coil 1 is arranged at a specific site in the body cavity of the subject P and an MRI image is displayed on the monitor, when the surface coil 1 is arranged on the outer surface of the subject P, imaging cannot be performed. An MRI image of a site containing cancer of the digestive system was obtained. In FIG. 3, the sequencer 12 receives a control signal from the computer system 10 which is a control center of the entire system, executes a pulse sequence, and sends each of X, Y, and Z from the gradient magnetic field power supply 13 to the gradient coil 8. The drive current for generating the gradient magnetic field can be supplied, and the transmission timing of the excitation pulse from the transceiver 9 to the surface coil 9 and the surface coil 1
The reception timing of the MR signal to the transmitter / receiver 9 is controlled.

For this reason, the surface coil 1 of the present embodiment is extremely useful especially in the diagnosis of cancer of the digestive system, and the handling after the diagnosis is extremely simple to enable this diagnosis. .

In the present embodiment, a single circular shape is shown as the surface coil, but an appropriately selected coil shape such as a rectangular shape can be adopted. Further, it is needless to say that the present invention is also included in the present invention as a multiple coil shape. The surface coil is generally coated with a resin to protect the coil, but the presence or absence of the resin coating does not restrict the present invention. In addition, although the body temperature is used in the present embodiment to restore the shape to the original memory shape, it goes without saying that the present invention also includes a design structure in which an external current is applied to restore the shape.

[Effect of the Invention] As described above, the detection coil for magnetic resonance imaging of the present invention is sent into a body cavity through, for example, a forceps channel of an endoscope, and has a size suitable for detecting an MR signal in the body cavity. Since the shape can be restored, it is easy to handle and extremely useful for obtaining an MRI image with a good S / N ratio of the organ.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing a surface coil of one embodiment to which the present invention is applied, and FIG. 2 shows a state in which the surface coil of one embodiment of the present invention is fed into a body cavity through a forceps channel of an endoscope. FIG. 3 is a diagram schematically showing a configuration for performing magnetic resonance imaging using a surface coil according to one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Surface coil, 2 ... Lead wire 3 ... Endoscope, 4 ... Forceps channel 5 ... Image processing unit, 6 ... Display 7 ... Main magnet, 8 ... Gradient magnetic field coil 9 ... Transmission / reception Machine, 10 ... Computer system

Claims (2)

(57) [Claims] 1. A shape which can be linearly reduced and deformed by cooling so as to be able to pass through a forceps channel of an endoscope, and is restored to an original memory shape suitable for detecting a magnetic resonance signal by heating due to a temperature in a body cavity. A detection coil for magnetic resonance imaging, wherein the detection coil is a shape memory alloy structure. 2. The method according to claim 1, wherein the shape is reduced and deformed at a temperature different from the temperature in the body cavity to maintain a shape capable of passing through a narrow opening, and restored to a shape suitable for detecting a magnetic resonance signal at the temperature in the body cavity. Detection coil for magnetic resonance imaging.