JP3597938B2 - Nuclear magnetic resonance inspection equipment - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear magnetic resonance examination apparatus (hereinafter, referred to as an MRI apparatus). The present invention relates to an MRI apparatus capable of easily performing an action.
[0002]
[Prior art]
An MRI device uses a nuclear magnetic resonance (hereinafter referred to as NMR) phenomenon to measure a tomographic image of an internal tissue of a human body as a subject or an NMR spectrum of a local site, and non-invasively provides information useful for medical diagnosis. It is an inspection device that can be obtained.
[0003]
For this reason, the MRI apparatus includes a magnet for generating a uniform magnetic field, a gradient coil for generating a gradient magnetic field for changing the magnetic field strength of the magnetic field generated by the magnet, and resonance excitation of nuclear spin at a target portion of the subject. And a high-frequency coil for detecting an NMR signal generated at a target site. The gradient magnetic field coil includes three gradient magnetic field coils that generate gradient magnetic fields in three axes (x, y, z) directions orthogonal to each other, and is incorporated in the bore of the magnet together with the high-frequency coil. The subject is transported to the measurement space, which is the center of the magnet, while lying on the patient table. In addition, it is equipped with a power supply for driving various coils, a receiving circuit for amplifying the detected NMR signal, a computer for controlling these circuit units and processing the NMR signal, an operator console and a monitor display for displaying the inspection results. I have.
[0004]
Here, in the MRI apparatus, the uniformity of the magnetic field to be used needs to be about 10 ppm so that errors due to distortion of the measured image or spectrum do not interfere with diagnosis. In order to achieve a static magnetic field of this uniformity, a superconducting magnet composed of a solenoid coil needs to have a length approximately twice as long as the inner diameter, so that the superconducting magnet has a narrow and long cylindrical shape. In addition, since the above-mentioned gradient magnetic field coil and high-frequency coil are incorporated, the subject is carried into the narrow and long inspection space in the superconducting magnet and is inspected.
[0005]
On the other hand, in recent years, there has been a demand that a doctor or the like wants to simultaneously perform a therapeutic action (IVR) during an examination. An MRI apparatus has been proposed (Japanese Patent Application Laid-Open No. 6-290939).
In such an MRI apparatus, for example, a pair of magnets are arranged vertically via a column, and a specially shaped gradient magnetic field coil is arranged close to these magnets, and the patient table is transported to a space sandwiched between both magnets. It is configured to With this MRI apparatus, a doctor or the like can approach a subject placed in the measurement space from an open side even during an examination to perform a treatment, and the treatment can be sequentially confirmed by an image.
[0006]
Incidentally, an RF coil for detecting an NMR signal is generally mounted as close as possible to an inspection site in order to improve the S / N ratio of the NMR signal and obtain a good inspection result. This is because the electromotive force induced in the coil is stronger as the coupling between the coil and the nuclear spin is denser (the shorter the distance). For example, in the inspection of the head, an inspection is performed while the cylindrical RF coil having an inner diameter of 28 cm and a length of 30 cm is mounted. Japanese Patent Publication No. 5-25492 discloses this type of technology.
[0007]
Such an RF coil usually moves the patient table after attaching the RF coil to the target portion of the subject before transporting the patient table to the measurement space, and moves the subject to the center of the magnet which is the measurement space. Transport.
[0008]
[Problems to be solved by the invention]
Such a conventional MRI apparatus has the following problem.
[0009]
First, when sent into a narrow magnet space with the detection high-frequency coil attached, the subject is given a great feeling of oppression, so that examination of children and claustrophobia patients cannot be performed. Secondly, it is difficult to observe the state of the subject during the examination, so that examination of a severe patient is difficult. Furthermore, MRI examinations of emergency patients who need to be treated at the same time as examinations are not possible.
[0010]
Furthermore, even if a doctor or the like wants to perform a treatment at the same time during the examination, the doctor cannot access the subject arranged in the magnet, and a high-frequency coil for detection is placed on the examination site. Since it is mounted, various treatments cannot be performed unless the subject is once taken out of the magnet. In this case, it is not possible to sequentially confirm the treatment by using images. Alternatively, in an examination in which a diagnosis needs to be made based on a change in an image before and after the treatment, the examination part moves to move the subject for the treatment. For this reason, there has been a problem that a process such as a calculation between images cannot be performed on a computer, and a problem that the accuracy of the calculation has been reduced.
[0011]
In contrast, an open MRI apparatus solves many of the above problems. Particularly, when a surface coil is used as the detection RF coil, the subject can be approached from the open side, and the surface coil is Installation and removal are also possible. However, in the case of a cylindrical coil, removing the mounted RF coil and re-mounting it is a work in a limited space even if it is open, so the workability is poor, and the subject is required to mount the coil. -There was a problem that the inspection site moved due to attachment and detachment.
[0012]
Therefore, an object of the present invention is to provide an MRI apparatus capable of easily attaching and detaching an RF coil without moving the subject after setting the subject in the measurement space. In addition, the present invention enables a doctor or the like to be located near the examination site, and performs treatment using a treatment instrument as needed for the subject at the same time as or during the examination without moving the subject. It is to provide an MRI apparatus which can be used.
[0013]
Another object of the present invention is to provide a test as little as possible to the subject and to prepare for the test in an open state in which a conversation with a nurse or the like can be made. At least a part of the high-frequency coil for detection can be mounted after being arranged at the position.
[0014]
[Means for Solving the Problems]
To achieve the above object, the MRI apparatus of the present invention comprises a magnetic field generating means for generating a static magnetic field, a gradient magnetic field, and a high-frequency magnetic field in a space where a subject is placed, a means for transporting the subject into the space, In an MRI apparatus including a unit for detecting an NMR signal generated at a target site and a unit for processing and displaying a nuclear magnetic resonance signal, the magnetic field generating unit forms an open space around the subject. And a means for moving the detection means into the space and attaching / detaching to / from the target portion of the subject in the space. The detecting means may also serve as a magnetic field generating means for generating a high-frequency magnetic field that resonates and excites a nuclear spin at a target site of the subject. In this case, the magnetic field generating means having a structure forming an open space around the subject may or may not include a means for generating a high-frequency magnetic field.
[0015]
The detecting means can be divided into two or more parts. In this case, the means for mounting / removing the detecting means moves and separates the part of the detecting means.
[0016]
In one aspect of the present invention, the attaching / detaching means includes a means for moving all or a part of the detecting means along the body axis direction of the subject. In another aspect of the present invention, the detecting means includes one or a plurality of surface coils, and the attaching / detaching means attaches / detaches the surface coil to / from a target portion of the subject from the side of the subject. In still another aspect, the attaching / detaching means includes a means for moving a part of the detecting means along a direction substantially orthogonal to the body axis direction of the subject.
[0017]
Further, the MRI apparatus of the present invention is a magnetic field generating means for generating a static magnetic field, a gradient magnetic field, and a high-frequency magnetic field in a space in which a subject is arranged, a means for transporting the subject in a space, and a target portion of the subject. Means for detecting the generated NMR signal, signal processing of the NMR signal, comprising means for displaying, the magnetic field generating means has a structure to form an open space around the subject, the detecting means, It can be divided into two or more parts, one part of which is fixed to the transporting means, and the other part of which is provided with an engaging part which engages with the part, and is attached to a target part of the subject in the space. It is configured to be detachable.
[0018]
In such an MRI apparatus, the examination site of the subject is arranged at the center of the magnet by the operation of the conveying means (for example, the patient table). After arranging the subject at a predetermined position, the operator selects a test site and a high-frequency coil, which is a detection means most suitable for the purpose of the test, and mounts it on the test site. At this time, the mechanism for moving the detecting means differs depending on whether the detecting means is a cylindrical high-frequency coil, a surface coil, or a divided coil, and moves along a body axis direction of the subject or a direction orthogonal to the body axis. Attach detection means.
[0019]
After the mounting, as in the case of the normal inspection, by activating the imaging sequence for the purpose of the inspection, the application of the gradient magnetic field and the high-frequency magnetic field and the measurement of the NMR signal are performed at a predetermined timing. The NMR signal is processed by a computer, an image or a spectrum of the inspection site is obtained, and displayed on a monitor.
[0020]
Next, the detecting means is removed from the inspection site in accordance with the inspection result or in order to perform a predetermined process. In this case, the high-frequency coil for detection can be removed by the above-described mechanism without moving the inspection site of the subject. After performing the necessary processing, a high-frequency coil for detection is attached to the inspection site again, and imaging is performed to confirm the contents of the treatment with an image.
[0021]
【Example】
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0022]
FIG. 2 is a bird's-eye view showing the entire configuration of the MRI apparatus to which the present invention is applied. This MRI apparatus includes a magnet 102 and a patient table 103, and incorporates a gradient coil 105 for generating a gradient magnetic field and a high-frequency coil 106 for irradiation for generating a high-frequency magnetic field in the magnet 102. The magnet 102 has a shape in which a pair of permanent magnets are vertically opposed to each other and supported by left and right columns, and the front surface on which the patient table 103 is provided is widely opened, and an open type structure having an opening further behind. The gradient magnetic field coil 105 and the high-frequency coil 106 for irradiation incorporated in the magnet 102 are also formed in a pair of upper and lower plates that match the structure of the magnet 102. The magnetic field intensity at the center of the magnet 102 is 0.3 Tesla, and a uniformity of 5 ppm is achieved in a spherical space having a diameter of 40 cm. The gradient magnetic field coil 105 can generate a gradient magnetic field in three axes orthogonal to each other. The irradiation high-frequency coil 106 and the detection high-frequency coil have a 12.6 MHz resonance characteristic. This value corresponds to the frequency at which hydrogen nuclei resonate at a magnetic field strength of 0.3 Tesla.
[0023]
The patient table 103 is provided with a top plate 104 that can move thereon, and the subject 101 is laid on the top plate 104 in a state of lying on his / her back, and is transported inside the magnet 102.
[0024]
As shown in FIG. 3, a detection high-frequency coil 202 (hereinafter, referred to as a detection coil) for detecting an NMR signal is provided in a space in a magnet suitable for an inspection purpose. Is attached to and removed from the subject's examination site disposed at the center position of the subject.
[0025]
The mounting / removal of the detection coil and the control of the operation of the patient table 103 and the top plate 104 are performed by the operation panel 107 arranged on the outer surface of the magnet 102. Although only two operation panels 107 are shown in the drawing, three operation panels are arranged in the apparatus shown in FIG. With these operation panels 107, a laboratory technician, a nurse, or a doctor (not shown) can control the movement of the patient table or the tabletop from any position in the front, rear, left, and right of the subject 101.
[0026]
The magnetic field generators 102 (105, 106) and the patient table 103 are installed in a room surrounded by a radio wave shielding wall 108 to prevent electromagnetic noise from being mixed into the NMR signal, and are connected to the gradient magnetic field coil 105. A gradient magnetic field power supply, a high-frequency power supply connected to the irradiation high-frequency coil 106, and a receiving circuit 113 connected to the detection coil are installed outside the radio wave shielding wall 108. It is housed in a housing 109 together with a sequencer 112 for controlling the operation of these power supplies and receiving circuits.
[0027]
Outside the radio wave shielding wall 108, a computer 111 for controlling the sequencer 112 and inputting the NMR signal amplified by the reception circuit 113 is provided. The computer 111 controls the sequencer 112 and is amplified by the reception circuit 113. An arithmetic process for converting the NMR signal into an image or spectrum suitable for diagnosis is performed, and the result is displayed on the monitor 114. The computer 111 is housed in the console 110, and an operator (a laboratory technician or a doctor) activates an imaging sequence suitable for a target test by operating buttons on the console 110. Note that the photographing sequence can also be started by operating a button on the operation panel 107 incorporated in the magnet 102 described above.
[0028]
Next, a moving mechanism of the detection coil 202 installed in the magnet will be described.
[0029]
FIGS. 1A and 1B are diagrams showing a case where a cylindrical detection coil 202 is used as one embodiment of the present invention. FIG. 1A is a diagram viewed from the side of the subject 101, and FIG. It is the figure seen from the head side. In this MRI apparatus, a guide 303 and a pedestal 306 for horizontally moving the detection coil 202 at the same level as the top plate 104 of the patient table are provided on the side of the magnet 102 opposite to the patient table 103. A plurality of rollers 305 are incorporated in the guide 303 so as to be able to move on the surfaces of the pedestal 306 and the magnet 102. The guide 303 may be configured to automatically move in conjunction with the movement of the top plate 104, or may be manually moved separately.
[0030]
Thus, the guide 303 can be connected to the top plate 104 that has entered from the opposite direction, or can be retracted in a direction away from the top plate 104 (backward). At this time, the pedestal 306 extends the rearward movement range of the guide 303. In addition, two grooves 304 for sliding the detection coil 202 are provided on the upper surface of the guide 303, and the lower end of the cylindrical detection coil 202 is fitted in the groove 304.
[0031]
On the other hand, a mat 308 for laying down the subject 101 is laid on the top plate 104 of the patient table, and a head support 301 for mounting the head of the subject 101 is fixed. A gap for inserting the detection coil 202 is formed below the head support 301, and two grooves for sliding the detection coil 202 are provided similarly to the upper surface of the guide 303. Thus, the detection coil 202 slid by being guided by the groove 304 of the guide 303 can be guided and slid by the groove of the top plate 104 as it is. A key hook 307 is provided at the tip of each of the top plate 104 and the guide 303 as a means for coupling with each other. Incidentally, such a connecting means is not essential to the present invention, but by this, the connection between the top plate 104 and the guide 303 can be surely performed, and the workability can be improved. The coupling means is not limited to the key hook 307, and any mechanical coupling means can be employed.
[0032]
Next, a flow when an inspection and a treatment are performed using the MRI apparatus having such a configuration will be described. FIG. 4 is a flowchart showing an example of the progress of the examination and treatment. First, the subject 101 is placed on the top plate 104 so that the head is placed on the head support 301 (1101). The top plate 104 is slid by the operation of the panel 107, and is conveyed until the inspection site of the subject 101, in the illustrated example, the head is located at the center 302 of the magnet 102 (1102). By this operation or another operation, the guide 303 of the detection coil also moves toward the center of the magnet, and at the stage where the inspection region of the subject 101 has moved to almost the center point 302 of the magnet 102, the tip of the top plate 104 and the guide The key hook 307 at the tip of the 303 is engaged, and both are integrally movable.
[0033]
In this state, the detection coil 202 on the guide 303 is slid along the groove 304 and attached to the inspection site (head) (1103). In this manner, the high-frequency coil 202 can be mounted without moving the subject from the state of being placed on the top board 104 at all. Here, an inspection mode suitable for the purpose of the inspection is activated, and an MRI inspection is performed (1104). Next, to perform the treatment, the detection coil 202 is removed from the inspection site (1105), and the treatment is performed (1106). In this case, the detection coil 202 is moved backward along the groove 304. At this time, the high-frequency coil 202 can be removed without moving the subject. Next, the detection coil 202 is again moved along the groove 304 to the inspection site side, mounted (1107), and the inspection proceeds in an inspection mode suitable for confirming the result of the treatment (1108). Since the subject does not move in the MRI examination, the comparison with the examination result in the step (1104) can be made with high accuracy. As a result of this inspection, if additional treatment is necessary (1109), the flow (1105) to (1108) is repeated again. If no additional treatment is necessary, the detection coil is removed from the examination site (1110), the top plate 104 is slid back to the patient table 103, and the patient table is retracted, thereby completing a series of examination steps.
[0034]
As described above, the detection coil of the present embodiment allows the doctor 201 to check the state of the subject while the head (examination site) of the subject 101 is carried to the center of the magnet as shown in FIG. The high-frequency coil 202 for detection can be attached to the examination site, and the first examination is completed, and the doctor 201 removes the high-frequency coil for detection from the subject's head in order to confirm the test result and perform a treatment process. be able to. Therefore, anxiety given to the subject can be minimized. Moreover, in this case, since the attachment and detachment can be performed without moving the subject's head, after the processing, the detection coil can be attached again and the examination can be continued under the same conditions.
[0035]
Although the high-frequency coil has been described as a detection coil in the above embodiment, it goes without saying that the high-frequency coil may be a coil that is also used for generating a high-frequency magnetic field.
[0036]
Next, as another embodiment of the present invention, details of a slide mechanism of a detection coil when inspecting a shoulder joint site will be described. FIG. 5 shows such an embodiment, in which a phased array coil in which three surface coils optimal for obtaining a tomographic image of a shoulder joint are combined is used as the detection coil 401. A guide 402 is provided on the top board 104 in order to mount such a phased array coil 401 on the shoulder joint of the subject 101 from the side of the subject 101 (a direction orthogonal to the body axis). A roller is embedded in the lower part of the guide 402, and enables the guide 402 to move in a direction approaching or separating from the side surface of the top plate 104. A pedestal 306 for securing the moving range of the guide 402 is attached to the side of the magnet 102 as in the embodiment of FIG. On the upper surface of the guide 402, a groove 404 for guiding the phased array coil 401 is formed along the same direction as the moving direction of the guide 402.
[0037]
On the other hand, the top board 104 can move not only in the body axis direction of the subject 101 but also in the left-right direction, so that the shoulder, which is the inspection site of the subject 101, can be positioned at the center of the magnet 102. A mat 405 is laid on the top plate 104 for vertical alignment, and a part of the mat 405 is provided with a space 406 in which a high-frequency coil for detection can be incorporated. Further, a slide rail 403 is formed on a side surface of the top plate 104 so that a distal end of the guide 402 is engaged with the slide rail 403.
[0038]
In the MRI apparatus having such a configuration as well, the moving process of the top board 104 is performed by an inspection technician, a doctor, or a nurse by operating the operation panel 107 on the side of the magnet as in the case of the above-described head inspection. Next, the guide 402 is moved, and its tip is engaged with the slide rail 403 on the right side surface of the top plate to be attached. After that, the phased array coil 401 is moved along the groove 404 of the guide 402 and is mounted on the inspection site. At this time, the lower end of the phased array coil 401 enters the space 406 between the top plate 104 and the shoulder, and the coil 401 can be mounted close to the inspection site. Similarly, the phased array coil 401 can be moved in the evacuation direction (to the right in the drawing) and detached. In the illustrated embodiment, the case where the detection coil is mounted on the right side of the subject 101 has been described, but the same can be performed on the left side.
[0039]
In the present embodiment, as in the embodiment of FIG. 1, in the initial stage of the test in which the test site of the subject 101 is carried into the center of the magnet 102, the detection coil or an accessory device accompanying the test is used. Subject Can be restrained Not Further, the carrying-in operation can be performed while looking at the subject's face or speaking with an open magnetic field generator. Further, when the inspection is performed in the procedure of inspection-processing-inspection as shown in the flow of FIG. 4, the inspection can be performed while the subject is placed in the magnet. In addition, the removal of the high-frequency coil for detection which is a hindrance in the treatment can be performed without moving the subject. Since there is no need to move the subject, the necessary treatment and operation of the device can be performed within the narrow magnet without the need for a plurality of caregivers. Further, since there is a guide rail for ensuring the reproducibility of the position of the detection coil, the operation can be performed easily in a short time. Further, since the shoulder joint of the inspection site is not moved, the position reproducibility of the inspection data before and after the processing is improved, and the calculation processing between the inspection data can be performed with high accuracy.
[0040]
In the embodiment described above, the case where the entire detection coil is attached to and detached from the subject 101 in the measurement space has been described, but the present invention is configured such that a part of the detection coil is attached and detached in the measurement space. Is also possible. Hereinafter, such an embodiment will be described.
[0041]
FIGS. 6A and 6B each show a high-frequency coil for head detection, which is divided into two parts, a base part 501 and an upper cover part 502 including a large open part. The base portion 501 is installed on the top plate 104 and also serves as a head support 505 on which the subject's head is placed. The base portion 501 and the upper cover portion 502 have a structure in which the upper cover portion 502 can be opened and closed around the hinge 503. By loosening the screw 504, the upper cover portion can be removed from the base portion.
[0042]
The detection coil shown in FIG. 6A further includes a contact portion 506 that is electrically connected to the base portion 501 when the upper cover portion 502 is closed. The upper half coil and the lower half coil incorporated in the base portion 501 are connected to form one substantially cylindrical high-frequency coil. That is, by realizing a high-frequency coil surrounding the subject at a uniform distance from the head, a highly efficient and uniform NMR signal can be detected.
[0043]
On the other hand, the detection coil shown in FIG. 6B is configured such that the connection between the upper half coil of the upper cover portion 502 and the lower half coil of the base portion 501 is made only at the hinge portion. In this case, the circuit configuration is such that the upper half coil and the lower half coil are electromagnetically coupled via a space. With this configuration, a more open high-frequency coil can be realized.
[0044]
Next, a flow when an examination and a treatment are performed using the MRI apparatus having such a configuration will be described with reference to a flowchart shown in FIG. First, when the detection coil shown in FIG. 6B is used, the upper cover 502 is opened, and the head of the patient table 103 is placed on the head support which also serves as the base 501. It is arranged on the plate 104 (1201). Next, the top plate 104 is moved to be conveyed so that the head, which is the inspection site, is located at the center of the magnet 102 (1202). With the inspection site located at the center of the magnet, the upper cover 502 is closed. Then, screw the upper half coil and the lower half coil together. In the case of the detection coil shown in FIG. As a result, the detection coil 202 can be mounted without moving the subject (1203). Here, an inspection mode suitable for the purpose of the inspection is started (1204). The inspection mode is operated, and treatment is performed while observing the inspection results. In this case, since the detection coil has an open shape, the treatment can be performed relatively easily. After the inspection and treatment, the high-frequency coil 202 is removed (1205), and the subject is carried out of the magnet (1206). Thus, the inspection and treatment steps are completed.
[0045]
As described above, according to the present embodiment, when the subject is carried into the center of the magnet, the sense of pressure given to the subject is reduced by keeping the upper cover portion open. In addition, the ability to have a conversation to relieve tension is the same as in the above-described embodiment. Further, when processing is required in the middle of the inspection, the necessary treatment can be performed by opening the upper cover portion or removing the upper cover portion. In addition, because of the open structure, depending on the contents of the treatment, the treatment can be performed with the upper cover part attached.
[0046]
In particular, in the embodiment shown in FIG. 6B, the sense of pressure given to the subject can be further reduced. Since the opening and closing and removal of the upper cover portion can be easily performed, treatment during the inspection can be easily performed.
[0047]
FIGS. 8A and 8B show an example in which a high-frequency coil for detecting a trunk portion is used as an embodiment using a detection coil divided into two similarly to FIG. The detection coil shown in FIG. 8 is also divided into two parts, a base part 701 and an upper cover part 702, like the detection coil of FIG. Both ends of the upper cover portion 702 engage with insertion portions provided at both ends of the base portion 701. These engagement portions can be fixed by tightening the screw 605, and can be released by loosening the screw. The insertion portion has a structure in which the upper cover portion 702 can be slid, for example, about 10 cm in the body axis direction (the direction indicated by the arrow 706). Thereby, the position of the desired inspection site and the position of the detection coil can be adjusted without strictly performing the alignment when placing the subject on the tabletop.
[0048]
In the detection coil of FIG. 8A, the upper cover portion 702 is provided with a large opening 704 except where the coil conductor is incorporated, so that the upper cover portion is required to be mounted on the subject. Measures can be taken.
[0049]
On the other hand, the detection coil shown in FIG. 8B differs from the detection coil shown in FIG. 8A in that the upper cover portion 801 has a flexible structure that can expand and contract. In order to realize a flexible structure, for example, plastic such as FRP covering the coil conductor is formed in a bellows shape as shown by a two-dot chain line in FIG. Can be formed. With such a flexible structure, the degree of freedom to match the body shape of the subject can be obtained, and the detection coil can be mounted even in a state in which a therapeutic instrument to be performed during the examination is incorporated.
[0050]
In these detection coils, a base portion 701 is arranged on the top plate 104 for inspection, and a mat 707 having the same thickness as the base portion is placed on the front and rear. The subject is conveyed to the space inside the magnet by sliding the top plate while the subject's waist is placed on the top plate 104 such that the waist is above the base portion. Thereafter, the upper cover part 702 (801) is attached to the base part 701 on which the examination part (lumbar part) of the subject is placed. The coil incorporated in the upper cover part 702 (801) and the coil incorporated in the base part 701 are connected by the insertion parts 703 on both sides, so that a high-frequency coil surrounding the torso of the subject is realized. You.
[0051]
According to the present embodiment, as in the case of the head inspection in FIG. 6, the upper cover can be easily removed from the torso, so that the treatment during the inspection can be easily performed. Further, since the detection coil shown in FIG. 8A has an open structure, depending on the contents of the treatment, the treatment can be performed with the upper cover attached.
[0052]
In the embodiments of FIGS. 5 to 7 described above, the attachment and detachment of the divided high-frequency coil is manually performed with a screw or the like. However, the mechanism for attachment and detachment is not limited to these embodiments. It can be changed arbitrarily without departing from the spirit. Further, in the above-described embodiment, a mechanism having no mechanism for moving the divided high-frequency coil portion has been described. However, such a mechanism may be provided.
[0053]
Next, an embodiment of an MRI apparatus provided with a mechanism for moving a part of a high-frequency coil will be described. 9A and 9B are diagrams showing an embodiment using a high-frequency coil for head inspection which is divided into upper and lower parts, where FIG. 9A is a view from the head side of the subject, and FIG. It is the figure seen from the side.
[0054]
In the MRI apparatus shown in FIG. 9, the lower detection coil 901 is fixed to the top plate similarly to the detection coil shown in FIG. 6, and also serves as a head support for the subject. On the other hand, the upper detection coil 902 is supported by a link mechanism as a moving means. That is, the upper detection coil 902 is supported by the lower end connecting portion 903a of the rhombus pantograph mechanism 903 composed of four links. The upper end connecting portion 903b of the pantograph mechanism 903 is fixed to the upper magnet 102. The pantograph mechanism 903 includes a slide mechanism 904 for guiding the vertical movement of the upper detection coil 902 supported by the lower end connecting portion 903a.
[0055]
One end of a nonmagnetic metal wire cable 905 is connected to the lower link as a means for expanding and contracting the pantograph mechanism 903. The other end of the wire cable 905 is connected to a handle 906 operated by an operator.
[0056]
In such a configuration, when the operator pulls up the handle 906 (rotates it in the direction of the arrow in the figure), the core wire of the wire cable 905 extends, and the lower link of the pantograph mechanism 903 is pushed down. The upper detection coil 902 which is deformed vertically and supported by the lower end connection portion 903a descends, is connected to the lower detection coil 901 and is mounted on the subject. Thereby, the upper coil and the lower coil function as an integrated high-frequency coil. Conversely, when the handle 906 is pulled down from this state, the upper detection coil 902 is raised by the pantograph mechanism 903, moves away from the subject, and moves to the upper evacuation position.
[0057]
Also in this embodiment, the head of the subject 101 is placed on a head support, which is the lower detection coil 901, and is sent together with the patient table top 303 so as to be located at the center of the magnet 102. After the head of the inspection site is disposed at a predetermined position, the high-frequency coil can be attached and detached by lowering or raising the upper coil with a simple operation of the handle. Therefore, when treatment and inspection are frequently performed, the entire inspection time can be significantly reduced.
[0058]
In this embodiment, an example is described in which a combination of a pantograph mechanism composed of a link and a wire cable is employed as a means for moving the upper detection coil up and down, but other hydraulic cylinders and air cylinders may be used as means for moving up and down. A known mechanism can be adopted as long as it does not affect the uniform magnetic field.
[0059]
Although the detection coil for the head inspection has been described, the configuration shown in FIG. 9 can be applied to a detection coil for the torso and the whole body or a detection coil that also generates a high-frequency magnetic field.
[0060]
【The invention's effect】
As described above, the MRI apparatus of the present invention is provided with a mechanism capable of mounting the detection high-frequency coil or a part thereof after disposing the subject at a predetermined position in the magnet, so that the subject can be loaded when the subject is carried in. The patient can be carried in without mounting the detection high-frequency coil, the feeling of pressure given to the subject can be minimized, and the examination can be prepared in an open state in which conversation with a nurse or the like is possible. Further, after carrying in, the MRI examination and treatment can be repeatedly performed without moving the subject, and a doctor or the like can approach the examination part and perform an appropriate treatment. Further, since the MRI examination and the treatment can be repeated without moving the subject, a highly accurate comparison can be performed when comparing two or more MRI examinations.
[Brief description of the drawings]
FIG. 1 is a view showing an embodiment of an MRI apparatus according to the present invention, wherein (a) is a view from the side of a subject and (b) is a view from the head.
FIG. 2 is an overall perspective view of an open MRI apparatus to which the present invention is applied.
FIG. 3 is a side view of the MRI apparatus of FIG. 2;
FIG. 4 is a diagram showing an example of an operation flow of the MRI apparatus according to the present invention.
FIG. 5 is a diagram showing another embodiment of the MRI apparatus according to the present invention.
FIGS. 6A and 6B are diagrams showing another embodiment of the present invention, wherein FIGS. 6A and 6B show different types of high-frequency coils for head detection. FIGS.
FIG. 7 is a diagram showing another example of the operation flow of the MRI apparatus according to the present invention.
FIGS. 8A and 8B are diagrams showing another embodiment of the present invention, wherein FIGS. 8A and 8B show different types of high-frequency coils for detecting a torso, respectively.
9A and 9B are diagrams showing another embodiment of the present invention, wherein FIG. 9A is a view from the head of the subject, and FIG. 9B is a view from the side of the subject.
[Explanation of symbols]
101 ... subject
102: magnet (magnetic field generating means)
103 ... Patient table (transportation means)
104 ... top plate
105 ... Gradient magnetic field coil (magnetic field generating means)
106: High frequency coil for irradiation
202: High frequency coil for detecting the head (detection means)
203: Guide (means for attaching / detaching)

Claims (7)

Magnetic field generating means for respectively generating a static magnetic field, a gradient magnetic field, and a high-frequency magnetic field in a space where a subject is arranged; means for transporting the subject into the space; and a nuclear magnetic resonance signal generated at a target portion of the subject Means for detecting, and a signal processing of the nuclear magnetic resonance signal, in a magnetic resonance inspection apparatus comprising means for displaying,
The magnetic field generating means has a structure forming an open space around the subject, and further moves the detecting means in the space, and attaches / detaches to / from a target portion of the subject in the space. A nuclear magnetic resonance inspection apparatus comprising: Magnetic field generating means for respectively generating a static magnetic field and a gradient magnetic field in a space in which a subject is arranged; means for transporting the subject into the space; and a high-frequency magnetic field for resonantly exciting a nuclear spin at a target site of the subject. Means for detecting a nuclear magnetic resonance signal generated at the target site of the subject and a signal processing the nuclear magnetic resonance signal, and a magnetic resonance inspection apparatus including means for displaying the magnetic resonance signal,
The magnetic field generating means has a structure forming an open space around the subject, and further moves the detecting means into the space, and attaches / detaches to / from a target portion of the subject in the space. A nuclear magnetic resonance inspection apparatus comprising: The said detection means can be divided | segmented into two or more parts, The said attaching / detaching means moves the divided part of the said detecting means, and attaches / detachs, The Claim 1 or 2 characterized by the above-mentioned. Nuclear magnetic resonance inspection equipment. 4. The nucleus according to claim 1, wherein the attachment / detachment unit includes a unit that moves all or a part of the detection unit along a body axis direction of the subject. Magnetic resonance inspection device. 2. The nuclear magnetic resonance inspection apparatus according to claim 1, wherein said detection means comprises one or a plurality of surface coils, and further comprises means for attaching / detaching to / from a target portion of said subject from a side of said subject. . 4. The nuclear magnetic resonance according to claim 3, wherein said attaching / detaching means includes means for moving a part of said detecting means along a direction substantially orthogonal to a body axis direction of said subject. Inspection equipment. Magnetic field generating means for respectively generating a static magnetic field, a gradient magnetic field, and a high-frequency magnetic field in a space where a subject is arranged; means for transporting the subject into the space; and a nuclear magnetic resonance signal generated at a target portion of the subject Means for detecting, and a signal processing of the nuclear magnetic resonance signal, in a magnetic resonance inspection apparatus comprising means for displaying,
The magnetic field generating means has a structure forming an open space around the subject, the detecting means can be divided into two or more parts, a part of which is fixed to the transport means, Another part is provided with an engaging part which engages with the part, and is attachable / detachable to / from a target portion of the subject in the space, and is a nuclear magnetic resonance inspection apparatus.

Images