JP2007068984A - Magnetic resonance imaging apparatus, coil support unit, high-frequency coil unit, and method for controlling magnetic resonance imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to change relative position between a subject and an RF coil, while the RF coil can be moved together with a top board for placing thereon the subject. <P>SOLUTION: The magnetic resonance imaging apparatus comprises: connection ports 612a, 612b for electrically connecting the upper RF coil 62u to a signal cable 614b which transmits at least one of a transmission signal supplied to the upper RF coil 62u, and a magnetic resonance signal detected by the upper RF coil 62u; guide grooves 615a, 615b for slidably guiding the connection ports 612a, 612b; and support members 611a, 611b arranged on the upper surface of the top board. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetic resonance imaging apparatus that images a subject using a magnetic resonance phenomenon, a coil support unit and a high-frequency coil unit that are suitable for use in the magnetic resonance imaging apparatus, and the magnetic resonance imaging apparatus is controlled. It relates to a control method.

  Magnetic resonance imaging (MRI) is based on a magnetic resonance signal (MR signal) generated by exciting a nuclear spin of a living tissue placed in a static magnetic field with a high-frequency signal having the Larmor frequency. Reconstruct the image. A magnetic resonance imaging apparatus (MRI apparatus) for imaging a subject using this MRI can obtain not only anatomical diagnostic information but also a lot of diagnostic information such as biochemical information and functional diagnostic information. It is important in the field of diagnostic imaging.

  In order to generate a high-quality image by the MRI apparatus, it is necessary to efficiently detect a weak MR signal from the subject, and many technical devices have been made for that purpose. As a high-frequency coil (RF coil) used for detecting an MR signal, a saddle type, a solenoid type, a slot resonator type, a bird cage type, or the like is widespread. Then, an optimal type of RF coil is selected and used in accordance with the frequency band, diagnosis target region, magnet type, and the like. For example, in a horizontal magnetic field type MRI apparatus using a cylindrical magnet, a bird cage type coil or a saddle type coil is used. In the vertical magnetic field type MRI apparatus, a solenoid coil is used. A surface coil with excellent detection sensitivity is used for local diagnostic sites such as the head and eyeballs.

  The MRI apparatus also requires an RF coil for transmitting a high-frequency signal. RF coils may be provided separately for transmission and reception, but because the transmission timing of high-frequency signals and the detection timing of MR signals are different, the same RF coil may be shared for transmission and reception. Is possible.

  By the way, in the MRI apparatus, there is a method of imaging over a wide range by imaging the subject while moving in the body axis direction. In order to realize such imaging, for example, an RF coil is fixed to a top plate on a bed via a support column, and an object placed on a support is moved between the RF coil and the top plate together with the support. A method of (sliding) has been proposed (see, for example, Patent Document 1).

  FIG. 6 is a perspective view of the moving mechanism of the subject described in Patent Document 1.

  A top plate 203 is disposed above the bed 201 and the auxiliary bed 202. A plurality of rollers 205 are attached to two parallel grooves 204 provided in the longitudinal direction of the top plate 203. An upper surface coil 206 and a lower surface coil 207 are fixed to the top plate 203 via a column 208.

  On the other hand, the support 209 on which the subject is placed is slidably disposed with respect to the top plate 203 while being supported by a plurality of rollers 205. Therefore, the support 209 and a subject (not shown) placed on the support 209 can slide between the top plate 203 and the upper surface coil 206. Then, when the helical shaft 211 is rotated by the motor 210 arranged at the end of the auxiliary bed 202, the support 209 moves in the longitudinal direction (that is, the body axis direction of the subject) together with the subject.

Thus, by moving the subject by the top plate 203 with respect to the fixed RF coils 206 and 207, the part of the subject to which the RF coils 206 and 207 are close, that is, the part to be imaged is changed. Can do.
US Pat. No. 5,808,468

  However, the RF coils 206 and 207 need to be positioned in the vicinity of the center of the static magnetic field formed inside the gantry during imaging. That is, although the RF coils 206 and 207 in the above configuration are arranged so as to sandwich the support body 209, the support body 209 has a sufficient thickness so as to support the weight of the human body. As a result, the RF coils 206 and 207 It becomes difficult to remove. Further, since the RF coil 206 is fixed at the center of the static magnetic field, when trying to move the imaging target site of the subject to the center of the static magnetic field, the head of the subject must be passed through the center of the static magnetic field. Sometimes it doesn't happen. In such a case, since the RF coil 206 passes near the head of the subject, there is a risk of mental pressure on the subject.

  The present invention has been made in consideration of such circumstances, and the object of the present invention is to allow the subject and the RF coil to move while the RF coil can be moved together with the top plate on which the subject is placed. It is also possible to change the relative position.

  A coil support unit according to a first aspect of the present invention is a magnetic resonance imaging apparatus that includes a top plate on which a subject is placed and images the subject using a high-frequency coil disposed on the top surface of the top plate. A coil support unit used, wherein a signal cable for transmitting at least one of a transmission signal supplied to the high frequency coil and a magnetic resonance signal detected by the high frequency coil is electrically connected to the high frequency coil. A connection port to be connected and a support member having a guide groove for slidably guiding the connection port and disposed on an upper surface of the top plate.

  The magnetic resonance imaging apparatus according to the second aspect of the present invention uses a high-frequency coil close to a desired region to be imaged in a subject placed on a top board and transmits a high-frequency pulse toward the subject and the subject A magnetic resonance imaging apparatus that performs at least one of detection of a magnetic resonance signal radiated from a coil support unit that supports the high-frequency coil, and the coil support unit is further supplied to the high-frequency coil. A connection port for electrically connecting the high-frequency coil to a signal cable for transmitting at least one of a transmitted signal and a magnetic resonance signal detected by the high-frequency coil, and a guide for slidably guiding the connection port And a support member disposed on the top surface of the top plate.

  A high frequency coil unit according to a third aspect of the present invention is a magnetic resonance radiated from a subject in response to applying a gradient magnetic field and a high frequency pulse to the subject in a static magnetic field placed on a top plate. A high-frequency coil unit used in a magnetic resonance imaging apparatus that images the subject based on a signal, wherein the at least one high-frequency coil performs at least one of transmission of the high-frequency pulse and detection of the magnetic resonance signal A connection port that electrically connects the high-frequency coil to a signal cable that transmits at least one of a transmission signal supplied to the high-frequency coil and a magnetic resonance signal detected by the high-frequency coil; And a slide unit for sliding the connection port in the longitudinal direction of the top plate.

  A magnetic resonance imaging apparatus according to a fourth aspect of the present invention includes a unit that generates a static magnetic field, a unit that applies a gradient magnetic field to a subject arranged in the static magnetic field, and a high-frequency pulse applied to the subject. A unit, a high-frequency coil that receives a magnetic resonance signal radiated from the subject, a couch on which the subject is placed, and a bed that can move the top plate in a longitudinal direction; and the magnetic resonance signal A unit for generating a magnetic resonance image based on the above, a connection port for making an electrical connection between the signal cable for transmitting the magnetic resonance signal and the high-frequency coil, and the connection port is located above the top plate in the longitudinal direction. A coil support unit that is slidable in the direction.

  The magnetic resonance imaging apparatus according to the fifth aspect of the present invention uses a high-frequency coil close to a desired site to be imaged in a subject placed on a top board and transmits a high-frequency pulse toward the subject and the subject A magnetic resonance imaging apparatus that performs at least one of detection of a magnetic resonance signal radiated from a transmission signal supplied to the high-frequency coil and at least one of a magnetic resonance signal detected by the high-frequency coil A connection port for electrically connecting the signal cable for transmitting one side and the high-frequency coil is provided, and the top plate has a guide groove on the upper surface thereof for slidably guiding the connection port.

  According to a sixth aspect of the present invention, there is provided a magnetic resonance imaging apparatus including a high-frequency pulse transmitted to a subject using a high-frequency coil close to a desired imaging target site in the subject placed on a top board and the subject. A magnetic resonance imaging apparatus that performs at least one of detection of a magnetic resonance signal radiated from a transmission signal supplied to the high-frequency coil and at least one of a magnetic resonance signal detected by the high-frequency coil A connection port for electrically connecting the signal cable for transmitting one side and the high-frequency coil; a guide groove for slidably guiding the connection port; and a support member disposed on an upper surface of the top plate, A moving unit that moves the connection port along the guide groove.

  According to a seventh aspect of the present invention, there is provided a magnetic resonance imaging apparatus comprising: a high-frequency coil that is close to a desired imaging target site in a subject placed on a top board; A magnetic resonance imaging apparatus for detecting at least one of magnetic resonance signals radiated from an upper coil disposed above the top surface of the top plate and used as the high-frequency coil, and the upper coil A connection port that electrically connects the high-frequency coil to a signal cable that transmits at least one of a transmission signal supplied to the magnetic resonance signal detected by the upper coil, and the connection port is slidable A support groove disposed on the top surface of the top plate, and a top surface of the top plate. It is disposed below and a lower coil which is used as the high-frequency coil.

  In the control method according to the eighth aspect of the present invention, a high-frequency pulse is transmitted to the subject and emitted from the subject using a high-frequency coil in the vicinity of a desired imaging target site in the subject placed on the top. A control method for controlling a magnetic resonance imaging apparatus that performs at least one of detection of a detected magnetic resonance signal, wherein the magnetic resonance imaging apparatus includes a transmission signal supplied to the high-frequency coil and the high-frequency coil. A connection port that electrically connects the high-frequency coil to a signal cable that transmits at least one of the detected magnetic resonance signals; a guide groove that slidably guides the connection port; and A support member disposed on an upper surface, and a moving unit that moves the connection port along the guide groove. The control method is such that when the top plate is moved, the moving unit is stopped until the high frequency coil reaches a predetermined position as the top plate moves, and the high frequency coil is After reaching the position, the high-frequency coil is moved at a speed almost equal to the moving speed of the top plate in the opposite direction to the direction in which the top plate is moved.

  A control method according to a ninth aspect of the present invention is a method for transmitting a high-frequency pulse toward a subject and radiating from the subject using a high-frequency coil close to a desired site to be imaged in the subject placed on a top board. In a control method for controlling a magnetic resonance imaging apparatus that performs at least one of detection of a detected magnetic resonance signal, the magnetic resonance imaging apparatus includes at least one of a transmission signal and a magnetic resonance signal supplied to the high-frequency coil. A control unit comprising: a moving unit that can move a connection port that electrically connects either the signal cable for transmitting either one or the high-frequency coil in a longitudinal direction of the top plate; The relative position between the subject and the high frequency coil is maintained until the high frequency coil is reached. Serial while maintaining the relative positional relationship between the high frequency coil and the predetermined position after reaching a predetermined position, changing the relative positional relationship between the subject and the radio frequency coil in the longitudinal direction.

  According to the present invention, the relative position between the subject and the RF coil can be changed while the RF coil can be moved together with the top plate on which the subject is placed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In this embodiment, two support members are attached on the top plate on which the subject is placed. The support member supports the RF coil so as to be slidable, and a guide groove for guiding the slide (movement) of the RF coil is formed on the support member. The connection port that can be attached to and detached from the end of the RF coil is connected to the end of a signal cable that transmits at least one of a transmission signal and a reception signal to the RF coil. As the RF coil moves, the connection port attached to the RF coil and the signal cable connected to the connection port are moved along the guide groove.

  The moving mechanism unit moves the RF coil in a direction opposite to the moving direction of the top board by a distance equal to the moving distance of the top board based on the moving direction and moving distance of the top board on which the subject is placed. For this reason, the RF coil is always arranged in the region of the static magnetic field and the gradient magnetic field regardless of the movement amount of the top plate and the subject. MRI imaging is performed on a subject site close to the RF coil.

  FIG. 1 is a block diagram of an MRI apparatus 100 according to this embodiment.

  The MRI apparatus 100 includes a static magnetic field generation unit 1, a gradient magnetic field generation unit 2, a transmission / reception unit 3, a calculation / storage unit 4, a top plate 5, an RF coil unit 6, an input unit 7, a display unit 8, a control unit 9, and a moving mechanism. Part 10 is provided.

  The static magnetic field generation unit 1 further includes a main magnet 11 and a static magnetic field power supply 12. For example, a superconducting magnet is used as the main magnet 11. The static magnetic field power supply 12 supplies a current to the main magnet 11. The main magnet 11 forms a strong static magnetic field.

  The gradient magnetic field generator 2 further includes a gradient magnetic field coil 21 and a gradient magnetic field power source 22. The gradient magnetic field coil 21 forms gradient magnetic fields in the X, Y, and Z axis directions orthogonal to each other. The gradient magnetic field power supply 22 supplies a current to the gradient magnetic field coil 21. The gradient magnetic field coil 21 superimposes a gradient magnetic field on a static magnetic field. A control signal is supplied to the gradient magnetic field power source 22 by the control unit 9, and the current supplied to the gradient magnetic field coil 21 is changed accordingly. Thereby, the gradient magnetic field generator 2 appropriately forms a gradient magnetic field for arbitrarily encoding the static magnetic field space. That is, by changing the pulse current supplied from the gradient magnetic field power source 22 to the X, Y, Z axis gradient magnetic field coil 21 based on the gradient magnetic field control signal, the gradient magnetic fields in the X, Y, Z axis directions are changed. A gradient magnetic field for slice selection, a gradient magnetic field for phase encoding, and a gradient magnetic field for readout (frequency encoding) that are synthesized and orthogonal to each other are set in arbitrary directions.

  The main magnet 11 and the gradient magnetic field coil 21 are accommodated in a gantry having a cavity. The center of the static magnetic field is located in the cavity.

  The transceiver unit 3 further includes a transmitter 31 and a receiver 32. The transmitter 31 includes a reference signal generator, a modulator, a power amplifier, and the like, and modulates a reference signal having the same frequency as the magnetic resonance frequency (Larmor frequency) determined according to the strength of the static magnetic field with a selective excitation waveform. By doing so, a high-frequency transmission signal is obtained. The transmitter 31 supplies the obtained transmission signal to the RF coil unit 6. The receiver 32 performs A / D conversion after performing signal processing such as intermediate frequency conversion, phase detection, and filtering on the MR signal output from the RF coil unit 6. Further, the receiver 32 includes a 90 ° phase shifter for performing phase alignment when the MR signals are two MR signals generated by a QD type volume coil and having phases different from each other by 90 °. .

  The calculation / storage unit 4 further includes a high-speed calculation circuit 41 and a storage circuit 42. The storage circuit 42 further includes an MR signal storage circuit 421 and an image data storage circuit 422. The MR signal storage circuit 421 stores the MR signal digitized by the receiver 32. The image data storage circuit 422 stores the image data generated by the high speed arithmetic circuit 41. The high-speed arithmetic circuit 41 performs reconstruction processing by two-dimensional Fourier transform on the MR signal stored in the MR signal storage circuit 421 to generate real space image data.

  The top plate 5 is one element constituting the bed. The shape of the top plate 5 is an elongated thin plate shape. The top plate 5 is slid in the longitudinal direction by the base portion of the bed. The subject 150 is placed on the top surface of the top plate 5 such that the body axis direction thereof substantially coincides with the longitudinal direction. Accordingly, the top 5 conveys the subject 150 in the body axis direction. The top 5 sends the subject 150 from outside the static magnetic field into the static magnetic field, and changes the position of the subject 150 with respect to the static magnetic field, thereby arbitrarily setting the imaging position with respect to the subject 150.

  The RF coil unit 6 further includes a coil support unit 61, an upper RF coil 62u, and a lower coil unit 62d. The coil support unit 61 is disposed on the top surface of the top plate 5 and supports the upper RF coil 62u in a state where the top plate 5 and the upper RF coil 62u are separated from each other and slidable in the longitudinal direction of the top plate 5. To do. The upper RF coil 62u transmits an RF pulse based on the transmission signal supplied from the transmitter 31. The upper RF coil 62u detects the MR signal radiated from the subject 150. The lower coil unit 62d is embedded in the top plate 5. The lower coil unit 62d transmits an RF pulse based on the transmission signal supplied from the transmitter 31. The lower coil unit 62d detects the MR signal radiated from the subject 150.

  The input unit 7 includes various input devices such as a switch, a keyboard, and a mouse on the console. The input unit 7 acquires information and instructions input by the operator. The information acquired by the input unit 7 includes, for example, various types of information regarding the subject 150, information regarding imaging conditions such as an imaging method and a pulse sequence, and display conditions. The instruction acquired by the input unit 7 is, for example, an instruction to start photographing, an instruction related to the movement of the top 5, or the like.

  The display unit 8 includes a video memory, a conversion circuit, and a monitor. When the image data stored in the image data storage circuit 422 is supplied to the display unit 8 via the control unit 9, the display unit 8 stores the image data in the video memory. Then, the image data and the accompanying information such as the subject information input from the input unit 7 are combined in the video memory. Image data created in the video memory by this synthesis is converted into a television signal and D / A converted by a conversion circuit to be converted into an image signal, which is then supplied to a monitor. The monitor displays an image represented by the image signal. As the monitor, a CRT (cathode-ray tube) or an LCD (liquid crystal display) can be used.

  The control unit 9 further includes a main control circuit 91, a sequence control circuit 92, and a moving mechanism control circuit 93. The main control circuit 91 includes a CPU and a storage circuit, and controls the MRI apparatus 100 in an integrated manner. The storage circuit of the main control circuit 91 stores information related to the shooting conditions and display conditions acquired by the input unit 7. The CPU of the main control circuit 91 supplies pulse sequence information to the sequence control circuit 92 based on the above information stored in the storage circuit. The pulse sequence information is, for example, information related to the magnitude of the current supplied to the gradient magnetic field coil 21, the level of the transmission signal, the application time, the application timing, and the like. The sequence control circuit 92 includes a CPU and a storage circuit, and controls the gradient magnetic field power source 22, the transmitter 31, and the receiver 32 according to the pulse sequence information. The moving mechanism control circuit 93 includes a CPU and a storage circuit, generates a control signal for moving the top plate 5 and the upper RF coil 62 u, and supplies the control signal to the moving mechanism unit 10.

  The moving mechanism unit 10 includes a top plate moving mechanism and an RF coil moving mechanism. The top plate moving mechanism moves the top plate 5 in the longitudinal direction. The RF coil moving mechanism moves the upper RF coil 62 u in the longitudinal direction of the top plate 5.

  2A and 2B are diagrams showing a specific configuration of the RF coil unit 6 shown in FIG. Fig.2 (a) shows the Ab-Ab cross section in FIG.2 (b). FIG.2 (b) shows the Aa-Aa cross section in Fig.2 (a).

  As shown in FIGS. 2A and 2B, the coil support unit 61 includes support members 611a and 611b, connection ports 612a and 612b, cable holding members 613a and 613b, signal cables 614a and 614b, and guide grooves 615a, 615b.

  The support members 611a and 611b are made of resin or the like so that the outline is a rectangular parallelepiped, for example. The support members 611a and 611b are fixed to the upper surface of the top plate 5, respectively. The support members 611 a and 611 b have the longitudinal direction substantially coincident with the longitudinal direction of the top plate 5. The support members 611a and 611b are aligned with each other along a direction orthogonal to the longitudinal direction of the top plate 5. The support member 611a and the support member 611b have an interval necessary for placing the subject 150 on the top 5 without being interfered with the support members 611a and 611b. Guide grooves 615a and 615b are formed in the upper portions of the support members 611a and 611b along the longitudinal direction of the support members 611a and 611b, respectively. The guide grooves 615a and 615b extend to the vicinity of both ends of the support members 611a and 611b.

  The connection ports 612a and 612b are supported by support members 611a and 611b, respectively, so as to be slidable along the guide grooves 615a and 615b. Both ends of the upper RF coil 62u can be attached to and detached from the connection ports 612a and 612b. The connection ports 612a and 612b support the upper RF coil 62u when the upper RF coil 62u is attached. The connection ports 612a and 612b electrically connect the upper RF coil 62u and the signal cables 614a and 614b, respectively, when the upper RF coil 62u is attached. In order to move the upper RF coil 62 u, the connection ports 612 a and 612 b are moved by the RF coil moving mechanism of the moving mechanism unit 10. For this reason, the RF coil moving mechanism has a parallel moving mechanism including a wire rope and a pulley, for example, and moves the connection ports 612a and 612b in parallel.

  The cable holding members 613a and 613b are made of a resin or the like in a rod shape or a tubular shape. One end of each of the cable holding members 613a and 613b is attached to each of the connection ports 612a and 612b. The cable holding members 613a and 613b are disposed inside the guide grooves 615a and 615b, and protrude through the support members 611a and 611b to the outside of the support members 611a and 611b. The cable holding members 613a and 613b hold the signal cables 614a and 614b, respectively, and guide the signal cables 614a and 614b from the inside of the guide grooves 615a and 615b to the outside of the support members 611a and 611b. The cable holding members 613a and 613b also define the positions of the signal cables 614a and 614b outside the support members 611a and 611b.

  The signal cables 614a and 614b electrically connect the upper RF coil 62u to the transmitter 31 and the receiver 32, and transmit transmission signals and MR signals.

  The upper RF coil 62u is an element coil accommodated in a case having a curved thin plate-like contour. Thus, when the upper RF coil 62u is attached to the connection ports 612a and 612b, a space for placing the subject 150 is formed between the upper RF coil 62u and the top plate 5 as shown in FIG. However, it is only necessary to form a space for placing the subject 150 between the upper RF coil 62u and the top plate 5, and the shape of the housing may be arbitrary.

  Now, the lower coil unit 62d includes a plurality of lower RF coils. The number of lower RF coils may be arbitrary, but in the present embodiment, three lower RF coils 62d-1, 62d-2, 62d-3 are provided. The lower RF coils 62 d-1, 62 d-2, 62 d-3 are arranged along the longitudinal direction of the top plate 5. The lower RF coils 62d-1, 62d-2, 62d-3 can transmit RF pulses and detect MR signals, respectively. The lower RF coils 62d-1, 62d-2, 62d-3 are individually connected to the transmitter 31 and the receiver 32. The lower RF coils 62d-1, 62d-2, 62d-3 may include only one element coil or may include a plurality of element coils.

  3A, 3B, and 3C are views showing how the top plate 5 and the upper RF coil 62u move.

  In a state where the top plate 5 is pulled out from the gantry and the upper RF coil 62u is removed from the connection ports 612a and 612b, the subject 150 can be easily placed on the top plate 5. When the top plate 5 is pulled out from the gantry in this way, the moving mechanism control circuit 93 keeps the connection ports 612a and 612b at the ends of the guide grooves 615a and 615b near the gantry. Thus, when the subject 150 is placed on the top 5 and the upper RF coil 62u is attached to the connection ports 612a and 612b, the state shown in FIG. 3A is formed.

  When attempting to image a certain part of the subject 150, the part to be imaged needs to be positioned in the vicinity of the center of the static magnetic field. Therefore, the movement mechanism control circuit 93 operates the movement mechanism unit 10 to move the top plate 5 so as to be fed into the gantry. As a result, the top 5 moves to the left in FIG. As the top 5 moves, the subject 150 and the coil support unit 61 also move. At this time, the movement mechanism control circuit 93 does not move the connection ports 612a and 612b. For this reason, the upper RF coil 62u also moves as the top plate 5 moves.

  If the upper RF coil 62u reaches the center of the static magnetic field as shown in FIG. 3B, the movement mechanism control circuit 93 starts moving the connection ports 612a and 612b while continuing to move the top plate 5. . The movement mechanism control circuit 93 sets the movement direction of the connection ports 612a and 612b to be opposite to the direction in which the top plate 5 is moved. Further, the moving mechanism control circuit 93 sets the moving speed of the connection ports 612a and 612b to be the same as the moving speed of the top board 5.

  At this time, the connection ports 612a and 612b are guided by the guide grooves 615a and 615b, respectively, and move relative to the top plate 5. However, since the top plate 5 continues to move, the connection ports 612a and 612b move. The position at the start will be maintained. Therefore, the upper RF coil 62u remains positioned at the center of the static magnetic field. For example, when the top 5 moves from the state shown in FIG. 3B to the left in the figure by ΔD, the connection ports 612a and 612b are connected to the support members 611a and 611b as shown in FIG. 3C. It moves by ΔD in the right direction in the figure. However, since the support members 611a and 611b move together with the top plate 5 by ΔD in the left direction in the figure, the connection ports 612a and 612b do not move with respect to the static magnetic field, as shown in FIG. In addition, the upper RF coil 62u remains located at the center of the static magnetic field. FIG. 4 is a diagram showing the movement of the connection ports 612a and 612b for realizing the movement of the upper RF coil 62u as shown in FIG. 4A shows the Ba-Ba cross section in FIG. 3B, and FIG. 4B shows the Bb-Bb cross section in FIG. 3C, with the positions of the support members 611a and 611b aligned. ing.

  When the upper RF coil 62u is positioned at the center of the static magnetic field in this way, the subject 150 moves in the static magnetic field as the top 5 moves. Therefore, the imaging target region can be arbitrarily changed. For example, in the state shown in FIG. 3B, the chest is the imaging target site, whereas in the state shown in FIG. 3C, the waist is the imaging target site.

  The lower coil unit 62d moves as the top plate 5 moves. Therefore, if the lower coil unit 62d is used for transmission of RF pulses and detection of MR signals, the transmitter 31 and the receiver 32 have a static magnetic field among the lower RF coils 62d-1, 62d-2, 62d-3. Select and use the one located at the center. In this case, for example, the lower RF coil 62d-1 is selected in the state shown in FIG. 3B, and the lower RF coil 62d-2 is selected in the state shown in FIG. 3C.

  Incidentally, when imaging is performed with the upper RF coil 62u fixed to the top plate 5, it is desirable to remove the support members 611a and 611b. That is, it is desirable that the support members 611a and 611b can be easily attached to and detached from the top plate 5. Therefore, in this embodiment, as shown in FIG. 5, lock mechanisms 66aa and 66ab are attached in the vicinity of both ends of the support member 611a. A similar locking mechanism is attached to the support member 611b. Then, by inserting the lock mechanisms 66aa and 66ab into the holes 51aa and 51ab provided in the top plate 5, the support member 611a can be easily attached to the top plate 5. The mounting of the support member 611b to the top plate 5 is the same.

  As described above, according to the present embodiment, the RF coil unit 6 moves as the top plate 5 moves, so that it can be positioned outside the gantry. For this reason, maintenance of the upper RF coil 62u and the lower RF coil unit 62d is facilitated.

  According to the present embodiment, since the upper RF coil 62u moves on the top plate 5, if the head of the subject 150 is not an imaging target, the upper RF coil 62u is close to the head of the subject 150. You don't have to.

  In addition, according to the present embodiment, the upper RF coil 62u is moved relative to the subject on the upper side of the top 5 so that a wide range of parts can be set as the imaging target. The coil 62u may be small. That is, since the upper RF coil 62u covers the upper portion of the subject 150 in a small area, the feeling of pressure on the subject can be reduced. In addition, since the lower RF coil unit 62d enables a wide range of parts to be imaged by arranging a plurality of lower RF coils, it is not necessary to move the lower RF coil unit 62d. For this reason, the structure of the moving mechanism part 10 can be simplified. In addition, since the lower RF coil unit 62d is embedded in the top plate 5, it does not give a sense of pressure to the subject even if the size is large.

  In addition, according to the present embodiment, the upper RF coil 62u mounted on the connection ports 612a and 612b is moved by moving the connection ports 612a and 612b. The upper RF coil 62u can be easily attached and detached as compared with the case where it is configured to move.

  In addition, according to the present embodiment, the movement of the upper RF coil 62u is automatically controlled in accordance with the movement of the top plate 5 so that the position of the upper RF coil 62u is maintained at the center of the static magnetic field. There is no need to separately operate the movement of the plate 5 and the movement of the upper RF coil 62u.

  Further, according to the present embodiment, the signal is provided by the cable holding members 613a and 613b that are disposed inside the guide grooves 615a and 615b and project outside the support members 611a and 611b through the support members 611a and 611b. Since the cables 614a and 614b are respectively held, the posture of the signal cables 614a and 614b on the top plate 5 can be reliably controlled, and the signal cables 614a and 614b can be reliably prevented from coming into contact with the subject 150. Thereby, even if heat is generated in the signal cables 614a and 614b due to the irradiation of the RF wave, it is possible to prevent the subject 150 from being damaged by a burn or the like. The US Food and Drug Administration's (FDA) Medical Equipment Radiation Office (CDRH) presents an indicator for cable processing to prevent signal cables from coming into direct contact with the subject in order to minimize burns on the subject. However, according to the present embodiment, this index can be cleared.

  This embodiment can be variously modified as follows.

  The upper RF coil 62u or the lower RF coils 62d-1, 62d-2, 62d-3 may be used only for either one of RF pulse transmission and MR signal reception. For example, all of the upper RF coil 62u and the lower RF coils 62d-1, 62d-2, 62d-3 may be used only for receiving MR signals. In this case, however, an RF coil for transmitting RF pulses is separately provided. Both the reception RF coil and the transmission RF coil may be moved like the upper RF coil 62u, or only the reception RF coil is moved, and the transmission RF coil is fixed in the gantry. You can keep it.

  The number of support members, connection ports, cable holding members, signal cables, and the like constituting the coil support unit 61 may be one or three or more.

  Guide grooves corresponding to the guide grooves 615a and 615b may be formed on the top surface of the top plate 5, and the connection port may be arranged in the guide grooves.

  The position where the upper RF coil 62u is stationary may be shifted from the center of the static magnetic field. However, the position where the upper RF coil 62u is stationary is preferably a position where the upper RF coil 62u can exhibit the desired performance.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

1 is a block diagram of an MRI apparatus according to an embodiment of the present invention. The figure which shows the specific structure of the RF coil unit shown by FIG. The figure which shows the mode of a movement of the top plate shown in FIG. 1, and an upper RF coil. The figure which shows the mode of a movement of the connection port for implement | achieving the movement of an upper RF coil as shown in FIG. The figure which shows the locking mechanism provided in the support member shown by FIG. The perspective view of the moving mechanism of the subject described in US Pat. No. 5,808,468.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Static magnetic field generation part, 2 ... Gradient magnetic field generation part, 3 ... Transmission / reception part, 4 ... Calculation / storage part, 5 ... Top plate, 6 ... Coil unit, 7 ... Input part, 8 ... Display part, 9 ... Control part DESCRIPTION OF SYMBOLS 10 ... Movement mechanism part, 11 ... Main magnet, 12 ... Static magnetic field power supply, 21 ... Gradient magnetic field coil, 22 ... Gradient magnetic field power supply, 31 ... Transmitter, 32 ... Receiver, 41 ... High-speed arithmetic circuit, 42 ... Memory circuit 51aa, 51ab ... hole, 61 ... coil support unit, 62u ... upper RF coil, 62d ... lower coil unit, 62d-1, 62d-2, 62d-3 ... lower RF coil, 66aa, 66ab ... lock mechanism, 91 ... Main control circuit, 92 ... Sequence control circuit, 93 ... Movement mechanism control circuit, 100 ... MRI apparatus, 421 ... Signal storage circuit, 422 ... Image data storage circuit, 611a, 611b ... Support members, 612a, 612b Connection ports, 613a, 613b ... cable holding member, 614a, 614b ... signal cable, 615a, 615b ... guide groove.

Claims (27)

A coil support unit used in a magnetic resonance imaging apparatus that includes a top plate for placing a subject and images the subject using a high-frequency coil disposed on the top surface of the top plate,
A connection port for electrically connecting the high-frequency coil to a signal cable that transmits at least one of a transmission signal supplied to the high-frequency coil and a magnetic resonance signal detected by the high-frequency coil;
A coil support unit comprising: a guide groove that slidably guides the connection port, and a support member disposed on an upper surface of the top plate.   The coil support unit according to claim 1, wherein the connection port is detachable near an end of the high-frequency coil.   The coil support unit according to claim 1, further comprising: a holding portion that has one end portion fixed to the connection port and holds the signal cable.   The coil support unit according to claim 1, wherein the connection port moves along the guide groove as the high-frequency coil moves.   The support member is detachable from the top plate, and further includes a lock mechanism that locks the support member with respect to the top plate when the support member is attached to the top plate. The coil support unit according to claim 1.   The coil support unit according to claim 1, wherein the guide groove is provided along a longitudinal direction of the top plate. At least one of transmission of a high-frequency pulse toward the subject and detection of a magnetic resonance signal radiated from the subject using a high-frequency coil close to a desired imaging target site in the subject placed on the top plate In a magnetic resonance imaging apparatus for performing
A coil support unit for supporting the high-frequency coil;
A connection cable that electrically connects the high-frequency coil to a signal cable that transmits at least one of a transmission signal supplied to the high-frequency coil and the magnetic resonance signal;
A magnetic resonance imaging apparatus, comprising: a guide groove that slidably guides the connection port; and a support member disposed on an upper surface of the top plate.   The coil support unit according to claim 7, wherein the connection port is detachable near an end of the high-frequency coil.   The magnetic resonance imaging apparatus according to claim 7, further comprising: a holding unit that has one end fixed to the connection port and holds the signal cable.   The magnetic resonance imaging apparatus according to claim 7, wherein the connection port moves along the guide groove as the high-frequency coil moves.   The support member is detachable from the top plate, and further includes a lock mechanism that locks the support member with respect to the top plate when the support member is attached to the top plate. The magnetic resonance imaging apparatus according to claim 7.   The magnetic resonance imaging apparatus according to claim 7, wherein the guide groove is provided along a longitudinal direction of the top plate. A top plate moving unit for moving the top plate;
The magnetic resonance imaging apparatus according to claim 7, further comprising a coil moving unit that moves the high-frequency coil in a direction opposite to a direction in which the top plate is moved.   The magnetic resonance imaging apparatus according to claim 13, wherein the coil moving unit moves the high-frequency coil at approximately the same speed as the moving speed of the top plate. Magnetic resonance imaging for imaging the subject based on a magnetic resonance signal emitted from the subject in response to applying a gradient magnetic field and a high-frequency pulse to the subject in a static magnetic field placed on a top plate In the high-frequency coil unit used in the device,
At least one high-frequency coil that performs at least one of transmission of the high-frequency pulse and detection of the magnetic resonance signal;
A connection port for electrically connecting the high-frequency coil to a signal cable that transmits at least one of a transmission signal supplied to the high-frequency coil and a magnetic resonance signal detected by the high-frequency coil;
A high-frequency coil unit comprising: a slide unit for sliding the connection port in the longitudinal direction of the top plate.   The coil support member according to claim 15, further comprising a guide groove that slidably holds the connection port, and supporting a high-frequency coil connected to the connection port on the top plate. High frequency coil unit. A signal cable for transmitting at least one of a transmission signal connected to the connection port and supplied to the high-frequency coil and a magnetic resonance signal detected by the high-frequency coil;
The high-frequency coil unit according to claim 16, wherein the guide groove is formed so as to guide the signal cable into the coil support member. The high frequency coil is slidable on the top plate in the longitudinal direction,
The high frequency coil unit according to claim 16, wherein the coil support member is disposed between the high frequency coil and the top plate.   The high-frequency coil unit according to claim 16, wherein the coil support member has a plurality of the guide grooves parallel to each other. A unit that generates a static magnetic field;
A unit for applying a gradient magnetic field to a subject arranged in the static magnetic field;
A unit for applying a high frequency pulse to the subject;
A high frequency coil for receiving a magnetic resonance signal radiated from the subject;
A couch for placing the subject, and a couch capable of moving the couch in the longitudinal direction;
A unit for generating a magnetic resonance image based on the magnetic resonance signal;
A coil support unit having a connection port for electrical connection between the signal cable for transmitting the magnetic resonance signal and the high-frequency coil, and allowing the connection port to slide in the longitudinal direction above the top plate; The magnetic resonance imaging apparatus characterized by the above-mentioned. At least one of transmission of a high-frequency pulse toward the subject and detection of a magnetic resonance signal radiated from the subject using a high-frequency coil close to a desired imaging target site in the subject placed on the top plate In a magnetic resonance imaging apparatus for performing
A connection port for electrically connecting the high-frequency coil and a signal cable that transmits at least one of a transmission signal supplied to the high-frequency coil and the magnetic resonance signal;
2. The magnetic resonance imaging apparatus according to claim 1, wherein the top plate has a guide groove on the top surface thereof for guiding the connection port to be slidable. At least one of transmission of a high-frequency pulse toward the subject and detection of a magnetic resonance signal radiated from the subject using a high-frequency coil close to a desired imaging target site in the subject placed on the top plate In a magnetic resonance imaging apparatus for performing
A connection cable that electrically connects the high-frequency coil to a signal cable that transmits at least one of a transmission signal supplied to the high-frequency coil and the magnetic resonance signal;
A support member having a guide groove for slidably guiding the connection port, and disposed on an upper surface of the top plate;
A magnetic resonance imaging apparatus comprising: a moving unit that moves the connection port along the guide groove.   When the top plate is moved, the moving unit is stopped until the high-frequency coil reaches a predetermined position as the top plate moves, and after the high-frequency coil reaches the predetermined position, The apparatus further comprises a control unit that controls the moving unit to move the high-frequency coil in a direction opposite to a direction in which the top plate is moved at a speed substantially equal to a moving speed of the top plate. Item 23. The magnetic resonance imaging apparatus according to Item 22. At least one of transmission of a high-frequency pulse toward the subject and detection of a magnetic resonance signal radiated from the subject using a high-frequency coil close to a desired imaging target site in the subject placed on the top plate In a magnetic resonance imaging apparatus for performing
An upper coil disposed above the top surface of the top plate and used as the high-frequency coil;
A connection port for electrically connecting the high-frequency coil and a signal cable that transmits at least one of a transmission signal supplied to the upper coil and the magnetic resonance signal;
A support member having a guide groove for slidably guiding the connection port, and disposed on an upper surface of the top plate;
A magnetic resonance imaging apparatus comprising: a lower coil disposed below the top surface of the top plate and used as the high-frequency coil.   The magnetic resonance imaging apparatus according to claim 24, wherein a plurality of the lower coils are arranged along an upper surface of the top plate. At least one of transmission of a high-frequency pulse toward the subject and detection of a magnetic resonance signal radiated from the subject using a high-frequency coil close to a desired imaging target site in the subject placed on the top plate In a control method for controlling a magnetic resonance imaging apparatus for performing
The magnetic resonance imaging apparatus comprises:
A connection cable that electrically connects the high-frequency coil to a signal cable that transmits at least one of a transmission signal supplied to the high-frequency coil and the magnetic resonance signal;
A guide member that slidably guides the connection port, and a support member disposed on an upper surface of the top plate;
A moving unit that moves the connection port along the guide part;
The control method is:
When the top plate is moved, the moving unit is stopped until the high-frequency coil reaches a predetermined position as the top plate moves.
After the high frequency coil reaches the predetermined position, the high frequency coil is moved in a direction opposite to a direction in which the top plate is moved at a speed substantially equal to the moving speed of the top plate. Control method. At least one of transmission of a high-frequency pulse toward the subject and detection of a magnetic resonance signal radiated from the subject using a high-frequency coil close to a desired imaging target site in the subject placed on the top plate In a control method for controlling a magnetic resonance imaging apparatus for performing
The magnetic resonance imaging apparatus comprises:
A connection port that electrically connects the high-frequency coil to a signal cable that transmits at least one of the transmission signal and the magnetic resonance signal supplied to the high-frequency coil can be moved in the longitudinal direction of the top plate. A mobile unit
The control method is:
Until the high frequency coil reaches a predetermined position, maintain the relative positional relationship between the subject and the high frequency coil,
After the high frequency coil reaches the predetermined position, the relative positional relationship between the subject and the high frequency coil is changed in the longitudinal direction while maintaining the relative positional relationship between the predetermined position and the high frequency coil. The control method characterized by making it do.

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