JPH0318349A - Magnetic resonance diagnosing device - Google Patents

Abstract

PURPOSE:To obtain a magnetic resonance(MR) signal of good S/N even with the inspecting part of a deep part by receiving and detecting the MR signal from the inspecting part by using a 1st coil housed freely projectingly in a coil housing tube. CONSTITUTION:While the 1st RF coil 3 is kept housed in the coil housing tube 22, the one end 23 is inserted into a specimen and is passed in the body. The 1st RF coil 3 is projected form the end 23 of the housing tube 22 by pressing the end of a coil introducing part 24 in the aperture on a hand side after the arrival at the inspecting part is confirmed. The 2nd RF coil 4 is then disposed in tight contact with the section corresponding to the outer side of the specimen in such a manner that this coil can be inductively coupled to the 1st RF coil 3. The MR signal is received and detected by the 2nd RF coil 4. Since the 2nd RF coil 4 exists on the outer side of the specimen and can exactly form the resonance circuit corresponding to resonance frequencies, the MR signal is received and detected with the good S/N and the data collection time is shortened even if the inspecting part exists in a relatively deep part.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides magnetic resonance signals (
The present invention relates to a magnetic resonance diagnostic apparatus that collects MR signals and utilizes them for diagnosis, and particularly relates to improvements in a high frequency coil (hereinafter referred to as RF coil) for transmitting or receiving and detecting the MR signals.

(Prior Art) In recent years, this type of magnetic resonance diagnostic apparatus has played a large role in medical diagnostic equipment.

That is, the subject is placed in a quiet magnetic field of several hundred to several thousand G,
The well-known magnetic resonance imaging method, in which a linear gradient magnetic field is superimposed on this to obtain the strength of the MR signal and the location of the signal source, is used to create an image, as well as information on the chemical shift of the target nuclide at a specific site in the living body (examination site). This is because if in vivo spectrostomiometry (biological MR analysis method) is used to obtain the following information, useful morphological information, pathological change data, etc. can be obtained non-invasively.

In this type of magnetic resonance diagnostic equipment, the biggest challenge is to efficiently detect minute amounts of MR signals from the examination site excited by RF pulses and to collect MR signals with a higher S/N ratio. . Therefore, it is necessary to arrange the RF coil for collecting MR signals as close as possible to the examination site.

In the aforementioned in-vivo spectrostomiometry, it is necessary to bring the RF coil close to the test site, but in this in-vivo spectrostometry, the test site is set to be localized to a specific tissue within the subject's body. Therefore, surface coils are often used as RF coils. In other words, this surface coil is capable of collecting MR signals only from a roughly hemispherical or disc-shaped portion directly below the coil, and the surface coil is placed close to the body surface of the subject so as to be closest to the examination site. By arranging them, it is possible to collect MR signals with a relatively high S/N ratio.

(Problem to be Solved by the Invention) However, when a region relatively deep from the body surface is to be examined, such as the myocardium, even if the surface coil is placed closely to the body surface, the area directly under this placement position cannot be inspected. There was a problem in that the distance to the site was large and MR signals with a good S/N ratio could not be obtained.

The present invention has been made to solve these conventional problems, and is a magnetic resonance diagnostic apparatus that can obtain MR signals with a good S/N ratio even for examination sites relatively deep from the body surface. Our goal is to provide the following.

[Tank of the Invention] (Means for Solving the Problem) In order to achieve the above object, a magnetic resonance diagnostic apparatus according to the present invention includes a coil storage tube that is bendable and has a minute inner and outer diameter; a first coil housed in the coil housing tube such that it can freely protrude from an opening at one end of the coil housing tube; and means for receiving and detecting magnetic resonance signals from an examination site using the first coil. The main point is to have the following.

Another aspect of the present invention provides a coil storage tube that is bendable and has a minute inner and outer diameter, and a first coil storage tube that is stored in the coil storage tube so as to be able to protrude from an opening at one end of the coil storage tube. The gist of the present invention is to include a coil, a second coil that can be inductively coupled to the first coil, and means for receiving and detecting magnetic resonance signals from an examination site using the second coil.

(effect) According to the above-mentioned elliptical precepts, the following effects are produced.

That is, the coil storage tube has a small inner and outer diameter and can accommodate the first coil, and the coil storage tube is inserted into the subject so that one end thereof is located at the examination site within the subject. If the first coil is inserted into the body and the first coil is protruded from the tip, the magnetic resonance signal of the test site can be received and detected by the first coil, so the test site can be located relatively deep from the body surface. M with good S/N ratio even if
An R signal can be obtained.

Further, when the first coil is opened and placed at the examination site within the subject, the second coil may be placed outside the subject so as to be inductively coupled to the first coil. Even if the first coil is inside the subject and cannot be well tuned, the second coil is outside the subject and can easily be tuned, so the second coil can capture the subject's magnetic resonance signals. Through reception and detection, an MR signal with a good S/N ratio can be obtained.

(Example) Hereinafter, an example in which the magnetic resonance diagnostic apparatus according to the present invention is applied to a magnetic resonance imaging apparatus (hereinafter referred to as an MRI apparatus) will be described with reference to FIGS. 1 to 4.

FIG. 1 shows the general structure of the MHI device. This MRI apparatus includes a static magnetic field coil (sometimes a shim coil for quiet magnetic field correction is added) 1 using a normal conduction or superconducting method as a magnet assembly configured to accommodate a subject P therein, and an MR. A gradient magnetic field coil 2 that generates a gradient magnetic field for providing positional information of a signal-induced region, a transmitting coil (not shown) that transmits a rotating high-frequency magnetic field for excitation, and a later-described IRF that receives and detects the excited MR signal. Coil (first coil) 3 and second R
An F coil (second coil) 4 is provided.

The electrical system has the following configuration. That is, if the static magnetic field coil 1 is a superconducting type, it includes a refrigerant supply control system, a static magnetic field control system 5 that mainly controls the energization of the static magnetic field power source, and an X-axis, Y-axis, and Z-axis gradient magnetic field power source. 6, 7, 8, transmitter 9, receiver 10-sequencer 11 for implementing a predetermined pulse sequence, computer system 12 and display 13 for controlling these and for processing the detected signal and displaying it.
Equipped with:

Supplementary note: As shown in FIGS. 2(a) and 2(b), the IRF coil 3 has both ends connected to a small capacitor 21 to form a loop shape, and is also capable of changing its shape such that it can be contracted into a long and thin shape. ing. And this IRF
The coil 3 is inserted into a coil storage tube 22 which is bendable, has a small inner and outer diameter, and has both ends open, and is inserted into the coil storage tube 22 by operating an opening (not shown) at one end of the coil storage tube 22. It is housed in such a way that it can freely protrude from the opening of the end portion 23 of. That is, the IRF coil 3 has a length that is appropriately set so that the coil storage tube 22 is inserted deep into the subject P from outside the subject P or over a long distance. The coil introducing section 24 has a total length of more than 300 mm, is bendable, and is electrically conductive.

Further, the IRF coil 3 preferably forms a resonant circuit corresponding to the frequency (resonance frequency) of the rotating high-frequency magnetic field for excitation used together with the capacitor 21, but as described above, the shape can be freely formed. Therefore, since the second RF coil 4, which will be described later, is configured to form a resonant circuit corresponding to the resonant frequency more accurately, it is not necessarily necessary to form a resonant circuit corresponding to the resonant frequency. . Note that the coil storage tube 22 may be a plastic or metal thin tube known as a catheter in the medical field.

Further, the second RF coil 4 is the second IRF coil 3 .
This is for extracting the MR signal from the examination site of the patient P by inductive coupling with the patient P. As shown in FIG. A resonant circuit is formed that corresponds to the frequency as accurately as possible. In addition, the code|symbol 28 is a coaxial cable.

Next, the operation of this embodiment will be explained.

First, the end of the coil introduction part 24 is pulled by the opening at one end of the coil storage tube 22, and the I
With the RF coil 3 stored, the other end 23 of the coil storage tube 22 is inserted through a part of the subject P such as the thigh, and this end 23 is directed toward the test site of the subject P. pass through the body. This end 23 is the test site, for example, the heart 11P.
After confirming that it has reached H using an X-ray diagnostic device, etc., push the end of the coil introduction part 24 with the proximal end opening of the coil storage tube 22 to remove the IRF from the end 23 of the coil storage tube 22.
Coil 3 is made to protrude.

Next, the second RF coil 4 is closely arranged on the body surface of the corresponding part of the outside of the subject P of the second IRF coil 3 at the heart 1iPH so as to be inductively coupled to the second IRF coil 3.
The F coil 4 receives and detects the magnetic resonance signal of the subject P.

Therefore, in this embodiment, the coil storage tube 22 has a small inner and outer diameter, which makes it easy to insert the IRF coil 3 into an examination site located relatively deep from the body surface through a blood vessel or the like. Even if the 2nd IRF coil 3 is inside the subject P and cannot be well tuned, the 2nd RF coil 3
Since the coil 4 is located outside the object P and can form a resonant circuit corresponding to the resonant frequency more accurately than the IRF coil 3,
2nd R inductively coupled with the 2nd IRF coil 3 located at the test site
The F coil 4 allows reception and detection of MR signals with a good S/N ratio even if the examination site is located relatively deep from the body surface, and therefore the data acquisition time is also shortened.

[Effects of the Invention] As explained above in detail, in the magnetic resonance diagnostic apparatus according to the present invention, the coil storage tube has a minute inner and outer diameter and can accommodate the first coil. If the tube is inserted into the subject so that one end of the tube is located at the test site within the test subject, and a first coil protrudes from the end, this first coil will generate magnetic resonance at the test site. Since signals can be received and detected, an MR signal with a good S/N ratio can be obtained even for an examination site located relatively deep from the body surface.

Further, when the first coil is protruded and placed at the examination site within the subject, if the second coil is placed outside the subject so as to be inductively coupled to the first coil, Even if the first coil is inside the subject and cannot be well tuned, the second coil is outside the subject and can be easily tuned. can be detected and an MR signal with a good S/N ratio can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration explanatory diagram of an MRI apparatus to which the present invention can be applied, and FIG. 2 (a>, (b) shows the IRF coil when it is projected from the coil storage tube and when it is stored in the coil storage tube. An explanatory diagram showing an example of each state, FIG. 3 is an IRF
It is an explanatory view showing an example of use of a coil and a second RF coil.

Claims (2)

[Claims] (1) A coil storage tube that is bendable and has minute inner and outer diameters; a first coil that is stored in the coil storage tube so as to be able to protrude from one end opening of the coil storage tube; 1. A magnetic resonance diagnostic apparatus comprising: means for receiving and detecting magnetic resonance signals from an examination site using one coil. (2) a coil storage tube that is bendable and has a minute inner and outer diameter; a first coil that is stored in the coil storage tube such that it can protrude from an opening at one end of the coil storage tube; 1. A magnetic resonance diagnostic apparatus comprising: a second coil that can be inductively coupled to the first coil; and means for receiving and detecting magnetic resonance signals from an examination site using the second coil.