JP2007054143A - Magnetic resonance imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic resonance imaging apparatus capable of increasing the S/N of an RF coil incorporated into a top plate and facilitating get-on and get-off of a subject to/from a bed. <P>SOLUTION: The magnetic resonance imaging apparatus is provided with the bed 1 having the top plate for the subject to lie down and reconstitutes images on the basis of magnetic resonance signals radiated from the subject. The top plate 11 includes: a lower top plate 15 for which a concave shape 16 capable of housing the subject is formed on the upper surface side; an upper top plate 14 which is provided so as to cover the concave shape, is controllable to a tense state and a loosened state and is for the subject to lie down; and a coil element arranged between the lower top plate and the upper top plate for receiving the magnetic resonance signals radiated from the subject. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetic resonance imaging apparatus, and more particularly to a bed of a magnetic resonance imaging apparatus.

  In a magnetic resonance imaging apparatus (hereinafter referred to as an MRI apparatus), there is an RF coil having an antenna function for detecting a weak resonance signal emitted from a human body after applying a high-frequency magnetic field to a subject.

  Since the resonance signal received by the RF coil is very weak, the RF coil is required to have a high S / N ratio. Conventionally, an RF coil that is in close contact with the diagnostic site as much as possible is prepared for each diagnostic site and used for diagnosis. It was.

  The RF coils for the spine and abdomen are placed on the top of the bed of the MRI apparatus and the subject is laid on the top, so that the subject who is the subject is placed on the top of the bed. He had to lie down at a higher position than when lying down. For this reason, when inserted from the opening of the high magnetic field generator, the subject may feel a sense of pressure because the upper wall approaches the subject.

  Therefore, by incorporating an RF coil into the top plate of the bed of the MRI apparatus, the subject is allowed to lie on the top plate with a margin between the subject and the upper wall. There is something that reduces the feeling of oppression. In addition, in order to obtain a high S / N ratio, there is one in which the RF coil is arranged along the body of the subject by bending the top plate and placing the RF coil on the curved top plate ( For example, see Patent Document 1.)

JP-A-9-38066

  However, when the top plate is curved, the body of the subject lying on the top sinks, so it may be difficult to get off the bed. In addition, in the case of a subject who cannot get on and off alone, a moving bed called a stretcher is attached to the bed of the MRI apparatus, and the stretcher is manually moved from the stretcher to the MRI apparatus bed or from the MRI apparatus bed. Move to. In this case, especially when moving from the bed of the MRI apparatus to the stretcher, the subject is sinking in the bed, so the operator needs to lift the sinking part and may be difficult to move. It was.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to increase the S / N ratio of the RF coil incorporated in the top board and to easily get on and off the subject to the bed. An object of the present invention is to provide a magnetic resonance imaging apparatus capable of performing the above.

  In order to solve the above problems, the invention according to claim 1 is provided with a bed having a couch for the subject to lie down, and reconstructs an image based on a magnetic resonance signal radiated from the subject. In the imaging apparatus, the top plate is provided so as to cover the concave shape with a lower top plate formed with a concave shape capable of accommodating the subject on the upper surface side, and is either in a stretched state or a relaxed state. An upper top plate for lying down on the subject that can be selectively controlled, and a magnetic resonance signal radiated from the subject is disposed between the lower top plate and the upper top plate. And a coil element to be included.

  In addition, the invention according to claim 2 further includes a pump in which the upper top plate is formed of a mat, forms a hollow portion by sealing the concave shape, and carries out air in and out of the hollow portion. The upper top plate can be controlled to be in a tensioned state or a relaxed state by taking in and out the air by the pump.

  In the invention according to claim 3, the upper top plate includes a sheet and a winding roller that winds and rewinds the sheet on at least one side of the position where the subject lies down. It is characterized in that it can be controlled in a tensioned state or a relaxed state by the winding and rewinding by the winding roller.

  According to a fourth aspect of the present invention, a mat is provided between the lower top plate and the upper top plate.

  The invention according to claim 5 is characterized in that the coil element is a planar array coil and is arranged along the concave shape.

  According to a sixth aspect of the present invention, the coil element is a planar array coil, and is arranged on the upper top plate side.

  The invention according to claim 7 is a bed having a cylindrical opening and having a magnetic field generator for generating a magnetic field, and a top plate for lying down on the subject, which can be taken in and out of the opening. A magnetic resonance imaging apparatus for reconstructing an image based on a magnetic resonance signal radiated from the subject, wherein the top plate has a concave shape capable of accommodating the subject on an upper surface side A lower top plate, an upper top plate for lying down on the subject, which is provided so as to cover the concave shape and can be selectively controlled in either a stretched state or a relaxed state; and the lower top plate, A coil element that is disposed between the upper top plate and receives a magnetic resonance signal radiated from the subject, and that detects that the bed comes out of the opening, and the detection When done, relax the upper top plate It is characterized in that it comprises a control means for controlling so.

  According to the present invention, when the upper top plate is in a relaxed state, the coil element is along the subject, so that a high S / N ratio can be obtained, and the upper top plate is in a stretched state. By doing so, since the upper top plate does not sink due to the lying down of the subject, it is possible to easily get on and off the subject.

[First Embodiment]
An MRI apparatus (magnetic resonance imaging apparatus) according to a first embodiment will be described with reference to the drawings.

  FIG. 1 is an external view of the MRI apparatus of the present embodiment. As shown in FIG. 1, the MRI apparatus includes a bed unit 1 on which a subject P (not shown) is placed, and a magnetic field generator that generates a magnetic field and detects a weak resonance signal emitted from the subject P (not shown). 2 and a console 3 (not shown) for performing overall system control and image reconstruction.

  Although not shown, the magnetic field generator 2 is a superconducting magnet that generates a static magnetic field in the axial direction of the cylindrical opening 21, a shim coil that equalizes the static magnetic field, and a gradient magnetic field in each of the X, Y, and Z axis directions. And an RF coil having an antenna function for applying a high-frequency magnetic field to the subject P and then detecting a weak resonance signal radiated from the subject P.

  The bed unit 1 accommodates the top plate unit 11 for the subject P to lie down, and the top plate unit 11 so as to be movable in the direction of the opening 21 of the magnetic field generator 2. The rail part 12 withdraws / inserts and the raising / lowering part 13 which hold | maintains the rail part 12 and raises / lowers are comprised.

  Furthermore, the bed part 1 is demonstrated in detail using FIG. FIG. 2 is a configuration diagram for explaining the configuration of the bed unit 1.

  The elevating unit 13 includes an elevating mechanism (not shown) that elevates the rail unit 12 and the top plate unit 11 placed on the upper side. For example, the subject who is the subject P rides on the top board 11 and lies down in the lowered state. Thereafter, the lift mechanism is raised to a position where it can be taken in and out with respect to the opening 21.

  The rail part 12 is mounted and fixed on the elevating part 13. And the top-plate accommodating part 121 which accommodates the top-plate part 11 is formed. An opening 123 is formed on the top plate housing 121 on the side of the magnetic field generator 2 so that the top 11 can be moved in the direction of the opening 21. A plurality of moving rollers 122 for moving the top plate portion 11 are arranged at the bottom of the top plate housing portion 121.

  The top plate portion 11 is mainly composed of an upper top plate 14 and a lower top plate 15. For example, a mat or the like is used for the upper top plate 14. The mat is in the form of a sheet having a predetermined thickness, and is configured, for example, by covering a foam material such as sponge with a sheet of vinyl chloride or the like. The lower top plate 15 is formed using, for example, hard plastic. The lower top 15 is formed with a curved concave recess 16 capable of accommodating the subject P on the upper surface side, and the upper top 14 forms a cavity 17 by sealing the recess 16 of the lower top 15 from above. To do. For example, the vicinity of the outer periphery of the upper top plate 14 may be bonded and sealed to the lower top plate 15 or may be assembled so as to be sealed with the upper top plate 14 using another member. A pump 110 for taking air in and out of the cavity portion 17 is provided, for example, on the end surface of the lower top plate 15. The upper top plate 14 can be in a tensioned state and a relaxed state by taking in and out air by the pump 110. Here, the stretched state is a state in which the upper top plate 14 is made flat and holds the subject P, and the relaxed state is a state in which the upper top plate 14 is made concave and the subject P is brought closer to the recess 16 or It means the state of being along. Further, a planar array coil 100 (coil element) that acquires a resonance signal from the subject P is disposed between the upper top plate 14 and the lower top plate 15. The planar array coil 100 is used when diagnosing the spine, abdomen, and the like, and is formed by arranging a plurality of loop-shaped coils with a predetermined overlap. In this example, the planar array coil 100 is installed along the recess 16.

  Next, the control configuration of the MRI apparatus according to the present embodiment will be described with reference to FIG. FIG. 3 is a block diagram showing a control configuration of the MRI apparatus of the present embodiment.

  The bed unit 1 is driven by a driving roller 111 for driving a pump 11 provided on the lower top plate 15 and a plurality of moving rollers 112 arranged on the bottom of the top plate accommodating unit 121. Means 124 and lifting mechanism driving means 131 for operating the lifting mechanism provided in the lifting unit 13 described above are included.

  The static magnetic field power source 202 of the magnetic field generator 2 supplies a current to the superconducting magnet to generate a static magnetic field. The shim coil power supply 203 supplies current to the shim coil in order to make the static magnetic field uniform. In addition, the gradient magnetic field power supply 201 generates a gradient magnetic field by supplying a pulse current to each of the x, y, and z coils that generate gradient magnetic fields in the X-axis, Y-axis, and Z-axis directions of the gradient magnetic field coil unit, respectively.

  Further, the transmitter 204 supplies an RF current pulse having a Larmor frequency for exciting a nuclear magnetic resonance by applying a high frequency magnetic field to the subject P to the above-described RF coil provided in the magnetic field generator 2. The receiver 205 takes in the resonance signal received by the planar array coil 100 and performs various signal processing such as pre-amplification, intermediate frequency conversion, position detection, low-frequency amplification, and filtering, and then performs A / D conversion. Digital data of the resonance signal is generated. Further, the resonance signal may be received by the RF coil.

  The console 3 includes a control / calculation unit 31, an operation unit 32, a display unit 33, and a storage unit 34.

  The control / arithmetic unit 31 includes a CPU and an internal memory (not shown), functions as a control unit that controls each part of the entire apparatus in accordance with a control program stored in the storage unit 34 and an input from the operation unit 32, and a resonance signal. It has a function as arithmetic means for reconstructing image data from the digital data. For example, the gradient magnetic field power supply 201, the transmitter 204, the receiver 205, etc. are controlled, digital data of the resonance signal from the receiver 205 is received, and the digital data is stored in the k space (also called Fourier space or frequency space) by the internal memory. The digital data is subjected to a two-dimensional or three-dimensional Fourier transform for each set to reconstruct image data in real space. Further, for example, in response to an input of an elevating instruction from the operation unit 32, the elevating mechanism driving unit 131 is controlled to operate the elevating mechanism. Further, for example, in response to an input of an instruction to place the upper top plate 14 in a stretched state or a relaxed state, the pump driving unit 111 is controlled to operate the pump 110 to change the upper top plate 14 to a desired state. Further, for example, upon receiving an instruction to move the top plate portion 11, the moving roller driving means 124 is controlled to operate the driving roller 121, so that the top plate portion 11 is put in and out of the opening portion 21.

  The storage unit 34 stores a control program, reconstructed image data, and the like.

  The display means 33 is a so-called monitor constituted by a liquid crystal display (LCD) or a cathode ray tube (CRT), and is controlled by the control / calculation unit 31 to display image data and the like. Therefore, the control / calculation unit 31 has a function as display control means.

  The operation unit 32 is used to input various instruction information from the operator, various information such as a password, etc., and although not shown, various keys (alphabetic keys, numeric keys, etc.), a mouse, a trackball, etc. are connected or installed. ing.

(Usage of the bed part)
Next, the usage mode in each state of the stretched state and the relaxed state of the upper top plate 14 of the top plate portion 11 will be described with reference to FIG.

  FIG. 4A shows a cross-sectional view of the top plate portion 11. As described above, the top plate portion 11 is composed of the upper top plate 14 and the lower top plate 15, and the hollow portion 17 is formed by sealing the concave portion 16 of the lower top plate 15 with the upper top plate 14. A planar array coil 100 is installed along the recess 16 of the lower top plate 15.

  First, for example, when the MRI apparatus is activated, the control / calculation unit 31 controls the pump driving means 111 so that air is introduced into the cavity 17 by the pump 110, and the upper top plate 14 is in a tensioned state. In this stretched state, the subject who is the subject P gets on the top plate 11 and lies down. FIG. 4B shows a state in which the subject P is lying on the top plate portion 11 (however, the subject P shows only the trunk portion; the same applies hereinafter). As shown in the figure, the subject P does not sink because the upper top plate 14 is stretched.

  Next, for example, by operating the operation unit 32 and inputting an instruction to change the upper top plate 14 from the stretched state to the relaxed state, that is, an instruction to evacuate the cavity 17, the control / calculation unit 31 instructs In response to this, the pump driving means 111 is controlled so that air is extracted from the cavity portion 17 by the pump 110, and the upper top plate 14 is brought into a relaxed state. Then, the subject P sinks together with the upper top plate 14 due to the weight of the subject P. FIG. 4 (c) shows a state in which the upper couch 14 is in a relaxed state and the subject is submerged. As the subject P sinks as shown in FIG. 4C, the planar array coil 100 becomes in a state along the subject P. In this state, for example, upon receiving an inspection start instruction from the operation unit 32, the control / calculation unit 31 controls the moving roller driving unit 124 so that the top plate unit 11 is inserted from the opening 21. When the plate portion 11 is inserted from the opening 21 and the examination is executed to excite nuclear magnetic resonance in the subject and the resonance signal is received by the planar array coil 100, the planar array coil 100 follows the subject P. Therefore, a high S / N ratio can be obtained.

  Subsequently, for example, upon receiving an instruction to end the inspection from the operation unit 32, the control / calculation unit 31 controls the moving roller driving unit 124 so that the top plate unit 11 comes out of the opening 21. It exits from the opening 21. Further, for example, by operating the operation unit 32 to input an instruction to change the upper top plate 14 from the relaxed state to the tensioned state, that is, an instruction to inject air from the cavity portion 17, the control / calculation unit 31 issues an instruction. In response, the pump driving means 111 is controlled so that air is introduced into the cavity portion 17 by the pump 110, and the upper top plate 14 is again stretched as shown in FIG. 4B. Since the subject P does not sink when the upper top plate 14 is in the tensioned state, it is not necessary for the operator to lift the subject P when moving the subject P to, for example, a stretcher. it can.

  Further, the pump driving means 111 is controlled by detecting an instruction to end the inspection, a control signal for taking out the top plate portion 11 from the opening portion 21, and the relaxed state before the top plate portion 11 is taken out from the opening portion 21. The time can be shortened by automatically starting the change from the tension state to the tension state. In this case, the control / calculation unit 31 has a function as a detection unit that detects the above-described instructions and control signals.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to the drawings. In the following, detailed description of configurations substantially similar to those of the first embodiment will be omitted, and different points will be mainly described.

  FIG. 5 shows a configuration of the top plate portion 11 of the present embodiment. According to FIG. 5, the top plate portion 11 of the present embodiment, for example, an upper top plate 14 made of a thin sheet such as cloth or vinyl, and winding and rewinding the sheet of the upper top plate 14. A winding roller 141 disposed on both sides of the recess 16 is included. By winding and rewinding the sheet of the upper top plate 14 by the rotation of the take-up roller 141, the upper top plate 14 can be in a stretched state and a relaxed state. Although not shown in detail, the upper top plate 15 has a take-up roller driving means 142 configured to drive the take-up roller 141, for example, a motor and a gear.

  In addition, the control configuration of the present embodiment is shown in the block diagram of the present embodiment in FIG. 6, but instead of the pump drive means 111 in the block diagram of FIG. Winding roller driving means 142 for driving is included.

  Next, the usage mode in each of the stretched state and the relaxed state of the upper top plate 14 of the top plate portion 11 will be described with reference to FIG.

  FIG. 7A shows a cross-sectional view of the top plate portion 11. The upper top plate 14 comprised with a sheet | seat as mentioned above and the winding roller 141 arrange | positioned at the both sides of the recessed part 16 are included.

  First, for example, when the MRI apparatus is activated, the control / calculation unit 31 controls the take-up roller driving unit 142 so that the upper top plate 14 of the sheet is taken up and the upper top plate 14 is stretched. In this stretched state, the subject who is the subject P gets on the top plate 11 and lies down. FIG. 7B shows a state in which the subject P is lying on the top plate 11. As shown in the figure, the subject P does not sink because the upper top plate 14 is stretched.

  Next, for example, the operation unit 32 is operated to input an instruction to change the upper top plate 14 from the stretched state to the relaxed state, that is, an instruction to rotate the winding roller 141 in the rewind direction in which the upper top plate 14 is loosened. Thus, the control / calculation unit 31 receives the instruction and rotates the winding roller 141 so as to rotate the winding roller 141 in the rewinding direction in which the upper top plate 14 is loosened. And the upper top plate 14 is in a relaxed state. Then, the subject P sinks together with the upper top plate 14 due to the weight of the subject P. FIG. 7 (c) shows a state in which the upper table 14 is in a relaxed state and the subject P is submerged. As the subject P sinks as shown in FIG. 7C, the planar array coil 100 becomes in a state along the subject P. Therefore, a high S / N ratio can be obtained as in the first embodiment.

  Subsequently, for example, upon receiving an instruction to end the inspection from the operation unit 32, the control / calculation unit 31 controls the moving roller driving unit 124 so that the top plate unit 11 comes out of the opening 21. It exits from the opening 21. Further, for example, by operating the operation unit 32, an instruction to change the upper top plate 14 from a relaxed state to a tensioned state, that is, an instruction to rotate the winding roller 141 in the direction of winding the upper top plate 14 is input. In response to the instruction, the control / calculation unit 31 controls the take-up roller driving unit 142 to rotate the take-up roller 141 in the take-up direction in which the upper top plate 14 is stretched by rotating the take-up roller 141. Then, as shown in FIG. 7B again, the upper top plate 14 is put in a stretched state. As in the first embodiment, when the subject P is moved to, for example, a stretcher, it is not necessary to lift the subject P because the subject P is submerged, so that the subject P can be moved easily.

  Further, a mat is provided between the lower top plate 15 and the upper top plate 14, for example, a mat is provided on a part of the upper top plate 14 (see FIG. 8), or a mat is provided on the concave portion 16, and the upper top plate 14 is provided. When the object is slack, the subject P may be along the planar array coil 100 via the mat. Further, the planar array coil 100 may be disposed on the upper top plate 14 (see FIG. 9) and may be along the subject P. Further, a winding roller 141 for winding and supplying the sheet of the upper top plate 14 may be provided only on one side.

1 is an external view of an MRI apparatus according to a first embodiment. It is a disassembled block diagram which shows the structure of the bed part of 1st Embodiment. It is a block diagram which shows the control structure of the MRI apparatus which concerns on 1st Embodiment. It is sectional drawing for demonstrating the usage condition of the top-plate part of 1st Embodiment. It is a disassembled block diagram which shows the structure of the top-plate part of 2nd Embodiment. It is a block diagram which shows the control structure of the MRI apparatus which concerns on 2nd Embodiment. It is sectional drawing for demonstrating the usage condition of the top-plate part of 2nd Embodiment. It is sectional drawing which shows the top-plate part of a structure different from the top-plate part shown in FIG. It is sectional drawing which shows the top-plate part of a structure different from the top-plate part shown in FIG.

DESCRIPTION OF SYMBOLS 1 Bed part 11 Top plate part 14 Upper top plate 15 Lower top plate 16 Recessed part 17 Cavity part 12 Rail part 13 Lifting part 2 Magnetic field generator 21 Opening part 3 Console 31 Control / calculation part 32 Operation part 33 Display part 34 Storage means 100 Planar array coil 110 Pump 111 Pump driving means 112 Moving roller 124 Moving roller driving means 131 Lifting mechanism driving means 141 Winding roller 142 Winding roller driving means 201 Gradient magnetic field power supply 202 Static magnetic field power supply 203 Shim coil power supply 204 Transmitter 205 Receiver

Claims (7)

A magnetic resonance imaging apparatus comprising a bed having a couch for a subject to lie down, and reconstructing an image based on a magnetic resonance signal emitted from the subject,
The top plate is
A lower top plate formed with a concave shape capable of accommodating the subject on the upper surface side;
An upper top plate for lying down on the subject that is provided so as to cover the concave shape and can be selectively controlled in either a stretched state or a relaxed state;
A magnetic resonance imaging apparatus comprising: a coil element that is disposed between the lower top plate and the upper top plate and receives a magnetic resonance signal emitted from the subject. The upper top plate is formed of a mat, and forms a cavity by sealing the concave shape,
A pump for taking air in and out of the cavity,
The magnetic resonance imaging apparatus according to claim 1, wherein the upper top plate is controllable in a tensioned state or a relaxed state by taking in and out the air by the pump.   The upper top plate includes a sheet and a winding roller that winds and rewinds the sheet on at least one side of the position where the subject lies down, and the winding by the winding roller The magnetic resonance imaging apparatus according to claim 1, wherein the magnetic resonance imaging apparatus can be controlled in a tensioned state or a relaxed state by rewinding.   The magnetic resonance imaging apparatus according to claim 3, further comprising a mat between the lower top plate and the upper top plate.   The magnetic resonance imaging apparatus according to claim 1, wherein the coil element is a planar array coil and is disposed along the concave shape.   The magnetic resonance imaging apparatus according to claim 1, wherein the coil element is a planar array coil and is disposed on the upper top plate side. A magnetic field generator that has a cylindrical opening and generates a magnetic field, and a couch for the subject to lie down, and has a bed that can be taken in and out of the opening, and is emitted from the subject A magnetic resonance imaging apparatus for reconstructing an image based on a magnetic resonance signal,
The top plate is
A lower top plate formed with a concave shape capable of accommodating the subject on the upper surface side;
An upper top plate for lying down on the subject that is provided so as to cover the concave shape and can be selectively controlled in either a stretched state or a relaxed state;
A coil element disposed between the lower top plate and the upper top plate and receiving a magnetic resonance signal radiated from the subject;
Detecting means for detecting that the bed is taken out of the opening;
A magnetic resonance imaging apparatus comprising: control means for controlling the upper top plate to be in a relaxed state when the detection is made.

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