JP2009165728A - Magnetic resonance imaging system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To raise photographing efficiency by performing accurate positioning in arranging an RF coil. <P>SOLUTION: A light projecting part 25 projects a laser beam, so as to display a sensitivity distribution image KB, indicating the sensitivity distribution of a reception coil 14b arranged on the placement surface of a cradle 15a, on the placement surface before performing scanning. The sensitivity distribution image can be divided in areas in response to sensitivities, so as to correspond to the kind of the RF coil to be arranged. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic resonance imaging (MRI) apparatus. In particular, an RF (Radio Frequency) pulse is transmitted to the imaging region of the subject in the static magnetic field space, and a scan that collects a magnetic resonance signal from the imaging region is performed, thereby obtaining a magnetic resonance image for the imaging region. The present invention relates to a magnetic resonance imaging apparatus to be generated.

  A magnetic resonance imaging apparatus is known as an apparatus for imaging a subject using a nuclear magnetic resonance (NMR) phenomenon. This magnetic resonance imaging apparatus is widely used in fields such as medical use and industrial use.

  When imaging a subject using a magnetic resonance imaging apparatus, a scan for collecting magnetic resonance signals from the subject is performed in an imaging space where a static magnetic field is formed so as to correspond to the scan conditions.

  Specifically, by accommodating a subject in an imaging space where a static magnetic field is formed, the direction of spins in protons in the subject is aligned with the direction of the static magnetic field. Get the magnetization vector. Thereafter, by irradiating an RF pulse having a resonance frequency, a nuclear magnetic resonance phenomenon is generated to excite the spin of the proton and change the direction of the magnetization vector. Then, a magnetic resonance signal generated when returning to the original magnetization vector is received. Thereafter, a magnetic resonance image is reconstructed based on the magnetic resonance signals collected in the execution of the scan (see, for example, Patent Document 1 and Patent Document 2).

  When performing a scan in the magnetic resonance imaging apparatus, the subject is placed on the placement surface of the cradle, and then the subject is aligned. Here, this alignment is performed using a so-called positioning light (see, for example, Patent Document 3). For example, a mark indicating a position corresponding to an isocenter in a cradle moved to the inside of the static magnetic field space is marked on the mounting surface of the cradle moved to the outside of the static magnetic field space with a laser marker (Laser Marker). ) To display by projecting laser light. Then, for example, alignment is performed by moving the subject such that the mark and the imaging region photographed on the subject correspond to each other (see, for example, Patent Document 4 and Patent Document 5).

  Further, for example, an RF coil such as a surface coil is disposed on the placement surface of the cradle on which the subject is placed. The RF coil is detachable, and is configured to increase sensitivity when receiving a magnetic resonance signal, for example, in a specific region such as a central region thereof. For this reason, when the RF coil is arranged on the subject, alignment is performed so that a specific region having high sensitivity in the RF coil corresponds to the imaging region of the subject. For example, when the cradle is moved to the static magnetic field space, alignment is performed such that a high-sensitivity portion in the RF coil corresponds to the isocenter that is the central position in the static magnetic field space.

JP 2006-175058 A JP 2003-225225 A Japanese Patent Laid-Open No. 11-299772 (see, for example, paragraph 0002) JP 2002-143114 A (see, for example, paragraph 0002) Japanese Unexamined Patent Publication No. 2006-247 (see, for example, FIGS. 3 and 4)

  However, when an RF coil is disposed, it may be difficult to clearly grasp the position of a specific region with high sensitivity in the RF coil. For this reason, it is difficult to perform the above alignment with high accuracy, and it may be necessary to perform the alignment again after performing the imaging. As a result, the shooting efficiency may decrease.

  In particular, since various types of RF coils are used depending on the position of the imaging region to be imaged in the subject, the above-described problem may be manifested.

  Therefore, the present invention provides a magnetic resonance imaging apparatus that can perform the alignment with high accuracy when arranging the RF coil and can improve the imaging efficiency.

  The present invention relates to magnetic resonance imaging that generates a magnetic resonance image for an imaging region by transmitting an RF pulse to the imaging region of a subject in a static magnetic field space and performing a scan that collects a magnetic resonance signal from the imaging region. A cradle in which the subject is placed on a placement surface and an RF coil is placed on the placement surface so as to correspond to an imaging region of the subject placed on the placement surface. And a light projection unit that projects light onto the mounting surface of the cradle, and the light projection unit displays a sensitivity distribution image indicating a sensitivity distribution of an RF coil disposed on the mounting surface of the cradle. The light is projected so as to be displayed on the mounting surface.

  Preferably, the light projection unit displays the sensitivity distribution image before the scan is performed.

  Preferably, the light projection unit is configured to project a laser beam as the light.

  Preferably, the light projection unit displays an image dividing a region according to the sensitivity of the RF coil as the sensitivity distribution image.

  Preferably, the light projection unit displays the sensitivity distribution image so as to correspond to the type of RF coil arranged in the imaging region of the subject.

  Preferably, the cradle moving unit moves the cradle between the inside and outside of the static magnetic field space, and the light projection unit moves the cradle to the outside of the static magnetic field space by the cradle moving unit. When this is done, the sensitivity distribution image is displayed.

  Preferably, when the cradle is moved to the static magnetic field space by the cradle moving unit, the light projection unit displays a center position image indicating a position corresponding to the center position of the static magnetic field space in the cradle. The light is projected so as to be displayed on the mounting surface of the cradle.

  Preferably, the light projection unit displays the center position image when the cradle is moved outside the static magnetic field space by the cradle moving unit.

  Preferably, a display unit that displays the magnetic resonance image on a screen is provided.

  According to the present invention, it is possible to provide a magnetic resonance imaging apparatus capable of performing alignment with high accuracy when arranging an RF coil and improving imaging efficiency.

  Hereinafter, an example of an embodiment according to the present invention will be described with reference to the drawings.

(Device configuration)
FIG. 1 is a configuration diagram showing a configuration of a magnetic resonance imaging apparatus 1 in an embodiment according to the present invention.

  As shown in FIG. 1, the magnetic resonance imaging apparatus 1 includes a scanning unit 2 and an operation console unit 3.

  In the present embodiment, in the magnetic resonance imaging apparatus 1, in the imaging space B in which the static magnetic field is formed, the scanning unit 2 transmits an RF pulse to the imaging region of the subject, and in the imaging region where the RF pulse is transmitted. Scanning is performed on the imaging region of the subject so as to obtain the generated magnetic resonance signal. Thereafter, in the magnetic resonance imaging apparatus 1, the operation console unit 3 generates a magnetic resonance image for the imaging region based on the magnetic resonance signals collected by performing the scan.

  The scanning unit 2 will be described.

  As shown in FIG. 1, the scanning unit 2 includes a static magnetic field magnet unit 12, a gradient coil unit 13, an RF coil unit 14, an object moving unit 15, an RF drive unit 22, a gradient drive unit 23, A data collection unit 24 and a light projection unit 25 are provided, and scanning is performed on the imaging region of the subject SU based on a control signal output from the operation console unit 3.

  The scanning unit 2 is formed to have a cylindrical shape, for example, and accommodates the subject SU with the columnar space at the center thereof as the imaging space B. The scanning unit 2 is placed on the subject moving unit 15 in the imaging space B where the static magnetic field is formed by the static magnetic field magnet unit 12 when scanning the imaging region of the subject SU. The RF coil unit 14 transmits an RF pulse so as to excite spins in the imaging region of the subject SU, and the gradient coil unit 13 transmits a gradient pulse to the imaging region of the subject SU to which the RF pulse has been transmitted. Then, the RF coil unit 14 receives a magnetic resonance signal generated in the imaging region of the subject SU.

  Each component of the scanning unit 2 will be described sequentially.

  The static magnetic field magnet unit 12 is a vertical magnetic field type, and is configured to form a static magnetic field along a direction z in which a pair of permanent magnets face each other, for example. In addition, the static magnetic field magnet unit 12 is a horizontal magnetic field type, includes a superconducting magnet (not shown), and is configured to form a static magnetic field in the imaging space B in which the subject SU is accommodated. Also good.

  The gradient coil unit 13 is configured to form a gradient magnetic field in the imaging space B where the static magnetic field is formed by the static magnetic field magnet unit 12 and to add spatial position information to the magnetic resonance signal received by the RF coil unit 14. Yes. Here, the gradient coil unit 13 includes three systems so as to correspond to the three axial directions orthogonal to each other in the x direction, the y direction, and the z direction. These transmit gradient pulses so as to form gradient magnetic fields in the frequency encode direction, the phase encode direction, and the slice selection direction according to the imaging conditions. Specifically, the gradient coil unit 13 applies a gradient magnetic field in the slice selection direction of the subject SU, and selects a slice of the subject SU to be excited when the RF coil unit 14 transmits an RF pulse. The gradient coil unit 13 applies a gradient magnetic field in the phase encoding direction of the subject SU, and phase encodes the magnetic resonance signal generated in the slice excited by the RF pulse. The gradient coil unit 13 applies a gradient magnetic field in the frequency encoding direction of the subject SU, and frequency encodes the magnetic resonance signal generated in the slice excited by the RF pulse.

  In the imaging space B where a static magnetic field is formed, the RF coil unit 14 transmits an RF pulse, which is an electromagnetic wave, to the imaging region of the subject SU to form a high-frequency magnetic field, and proton spins in the imaging region of the subject SU. Excited. The RF coil unit 14 receives an electromagnetic wave generated from protons in the imaging region of the excited subject SU as a magnetic resonance signal. Here, as shown in FIG. 1, the RF coil unit 14 includes a transmission coil 14a and a reception coil 14b.

  Here, the transmission coil 14a is, for example, a birdcage-type body coil, and is disposed so as to surround the imaging region of the subject SU, and transmits an RF pulse.

  On the other hand, the receiving coil 14b is detachable, for example, is disposed so as to correspond to the imaging region of the subject SU, and receives a magnetic resonance signal from the imaging region. For example, the receiving coil 14b is provided with a surface coil (not shown) in a housing in which an accommodation space (not shown) for accommodating the imaging region of the subject SU is formed, and the subject SU is provided in the accommodation space. The magnetic resonance signal is received by the surface coil.

  Further, the receiving coil 14b is provided with a positional mark 14M on the surface thereof, and is configured to detect the position of the positional mark 14M. Although details will be described later, for example, after a region including the positional mark 14M is imaged by an imaging device (not shown) such as a fixed camera and a digital image is acquired, the data processing unit 31 analyzes the digital image. Thus, the positional information of the positional mark 14M is calculated.

  The subject moving unit 15 includes a cradle 15a and a cradle moving unit 15b, and the cradle 15a is moved between the inside and the outside of the imaging space B based on a control signal output from the control unit 30. The moving unit 15b is configured to move.

  Here, the cradle 15a of the subject moving unit 15 is a table having a placement surface on which the subject SU is placed. As shown in FIG. 1, the cradle moving unit 15b moves the cradle 15a horizontally and vertically. z is moved in and out of the imaging space B where a static magnetic field is formed. As shown in FIG. 1, the cradle 15a is arranged such that a receiving coil 14b for receiving a magnetic resonance signal from the imaging region of the subject SU placed on the placement surface is arranged on the placement surface. It is configured.

  The cradle moving unit 15b of the subject moving unit 15 is configured to move the cradle 15a between the inside and outside of the imaging space B. That is, the cradle moving unit 15b is configured to be accommodated in the imaging space B by moving the cradle 15a from the outside to the inside of the imaging space B. The cradle moving unit 15b includes, for example, a roller drive mechanism, and drives the roller by an actuator to move the cradle 15a in the horizontal direction xy. The cradle moving unit 15b includes, for example, an arm type driving mechanism, and moves the cradle 15a in the vertical direction z by changing the angle between the two intersecting arms.

  The RF drive unit 22 is configured to drive the RF coil unit 14 to transmit an RF pulse in the imaging space B so as to form a high-frequency magnetic field in the imaging space B. Specifically, the RF drive unit 22 uses a gate modulator (not shown) to output a signal output from an RF oscillator (not shown) based on a control signal output from the operation console unit 3 at a predetermined timing. After the signal is modulated into a predetermined envelope signal, the signal modulated by the gate modulator is amplified by an RF power amplifier (not shown) and output to the RF coil unit 14 to transmit an RF pulse.

  Based on the control signal output from the operation console unit 3, the gradient driving unit 23 applies a gradient pulse to the gradient coil unit 13 to drive the gradient coil unit 13, thereby generating a gradient magnetic field in the imaging space B in which a static magnetic field is formed. It is configured to let you. The gradient drive unit 23 includes three systems of drive circuits (not shown) corresponding to the three systems of gradient coil units 13.

  The data collection unit 24 is configured to collect magnetic resonance signals received by the RF coil unit 14 based on control signals output from the operation console unit 3. Here, in the data collection unit 24, the phase detector (not shown) detects the magnetic resonance signal received by the RF coil unit 14 using the output of the RF oscillator (not shown) of the RF drive unit 22 as a reference signal. Thereafter, using an A / D converter (not shown), the magnetic resonance signal, which is an analog signal, is converted into a digital signal and output.

  The light projection unit 25 includes a plurality of laser markers that irradiate laser light. Based on a control signal output from the operation console unit 3, the light projection unit 25 applies laser light on the placement surface on which the subject SU is placed in the cradle 15a. Is configured to project. Here, as shown in FIG. 1, the light projection unit 25 is installed on the surface of the scanning unit 2 on the side where the cradle 15a is carried into the imaging space B by the cradle moving unit 15b.

  In the present embodiment, the light projection unit 25 mounts a sensitivity distribution image indicating the sensitivity distribution of the receiving coil 14b arranged on the mounting surface of the cradle 15a before the subject SU is scanned. Laser light is projected so as to display on the surface. Although details will be described later, the light projection unit 25 displays an image that divides the region as the sensitivity distribution image in accordance with the reception sensitivity of the reception coil 14b. For example, an image that divides the range of the receiving sensitivity of the receiving coil 14b with a straight line is displayed as a sensitivity distribution image. Further, the light projection unit 25 displays this sensitivity distribution image so as to correspond to the type of RF coil arranged in the imaging region of the subject SU.

  Here, the light projection unit 25 displays this sensitivity distribution image when the cradle 15a is moved outside the imaging space B by the cradle moving unit 15b. Specifically, based on the positional information of the positional mark 14M provided on the receiving coil 14b, the position where the laser light is projected is adjusted so as to correspond to the position of the receiving coil 14b arranged in the cradle 15a, and the sensitivity is adjusted. The distribution image is displayed on the placement surface.

  Further, in the present embodiment, the light projection unit 25 has a center position indicating a position corresponding to the center position of the imaging space B in the cradle 15a when the cradle 15a is moved to the imaging space B by the cradle moving unit 15b. Laser light is projected so that an image is displayed on the mounting surface of the cradle 15a. For example, an image showing a cross shape is displayed as the center position image. Here, the light projection unit 25 displays the center position image when the cradle 15a is moved to the outside of the imaging space B by the cradle moving unit 15b.

  The operation console unit 3 will be described.

  As illustrated in FIG. 1, the operation console unit 3 includes a control unit 30, a data processing unit 31, an operation unit 32, a display unit 33, and a storage unit 34. The operation console unit 3 controls the scan unit 2 so as to scan the imaging region of the subject SU. Then, the operation console unit 3 generates a magnetic resonance image for the imaging region of the subject SU based on the magnetic resonance signals collected by the scanning unit 2 performing the scan, and the generated magnetic resonance image is displayed. indicate.

  Each component of the operation console unit 3 will be described sequentially.

  The control unit 30 includes a computer and a memory that stores a program that causes the computer to execute predetermined data processing, and controls each unit. Here, the control unit 30 outputs a control signal to each of the RF drive unit 22, the gradient drive unit 23, and the data collection unit 24 so as to correspond to the set scan condition, thereby executing a scan. At the same time, a control signal is output to the data processing unit 31, the display unit 33, and the storage unit 34 to perform control.

  In the present embodiment, the control unit 30 outputs a control signal to the light projection unit 25 to control the operation of the light projection unit 25.

  Here, the controller 30 displays a sensitivity distribution image indicating the sensitivity distribution of the receiving coil 14b arranged on the placement surface of the cradle 15a on the placement surface before the subject SU is scanned. As described above, laser light is projected onto the light projection unit 25. For example, the control unit 30 controls the operation of the light projection unit 25 so as to display an image that divides the region according to the reception sensitivity of the reception coil 14b as the sensitivity distribution image. Specifically, the sensitivity distribution image is displayed on the placement surface corresponding to the position of the receiving coil 14b arranged in the cradle 15a based on the positional information of the positional mark 14M provided on the receiving coil 14b. To control. In the present embodiment, the control unit 30 controls the light projection unit 25 to display the sensitivity distribution image when the cradle 15a is moved outside the imaging space B by the cradle moving unit 15b.

  Further, the control unit 30 controls the operation of the light projection unit 25 so as to display different sensitivity distribution images corresponding to the types of the reception coils 14b arranged in the imaging region of the subject SU. That is, the operation of the light projection unit 25 is controlled so as to display a sensitivity distribution image corresponding to the type of the receiving coil 14b arranged.

  Further, in the present embodiment, when the cradle 15a is moved to the imaging space B by the cradle moving unit 15b, the control unit 30 corresponds to the center position of the imaging space B on the placement surface of the cradle 15a. A laser beam is projected on the light projection unit 25 so as to display a center position image indicating the above. Here, the control unit 30 performs control so that the light projection unit 25 displays the center position image when the cradle 15a is moved outside the imaging space B by the cradle moving unit 15b. That is, the position corresponding to the position of the isocenter of the imaging space B is displayed on the cradle 15a moved out of the imaging space B.

  The data processing unit 31 includes a computer and a memory that stores a program that executes predetermined data processing using the computer, and performs data processing based on a control signal output from the control unit 30. To do.

  Here, the data processing unit 31 is configured to set scan conditions for performing a scan on the subject SU based on a command input by the operator in the operation unit 32.

  In addition, the data processing unit 31 uses the magnetic resonance signals collected by the scan unit 2 executing a scan as raw data so as to correspond to the scan conditions set above, and obtains an imaging region of the subject SU. Is configured to generate a magnetic resonance image. Specifically, the magnetic resonance signal collected by the data collection unit 24 by performing the scan is acquired as a digital signal, and image reconstruction processing is performed on the magnetic resonance signal converted into the digital signal, so that the subject A magnetic resonance image is generated for the imaging region of the SU. For example, the magnetic resonance image is reconstructed by performing an inverse Fourier transform on the magnetic resonance signals collected so as to correspond to the k-space. Then, the generated image data of the magnetic resonance image is output to the display unit 33.

  In the present embodiment, for example, the data processing unit 31 captures image data of a digital image captured by an imaging device (not shown) such as a fixed camera for an area including the positional mark 14M provided in the receiving coil 14b. In response to the digital image being analyzed by the data processing unit 31, the positional information of the positional mark 14M is calculated.

  The operation unit 32 includes operation devices such as a keyboard and a pointing device. The operation unit 32 is input with operation data by an operator and outputs the operation data to the control unit 30.

  The display unit 33 includes a display device such as an LCD (Liquid Crystal Display), and displays an image on the display screen based on a control signal output from the control unit 30. Here, the display unit 33 displays on the display screen an operation image indicating input items for the operator to input operation data. Specifically, a menu image indicating input items to be input for scan parameters when scanning the subject SU is displayed on the display screen. In addition, the display unit 33 receives the image data of the magnetic resonance image generated for the subject SU from the data processing unit 31 and displays it on the display screen.

  The storage unit 34 includes a memory and stores various data. The storage unit 34 is accessed by the control unit 30 as necessary for the stored data.

(Operation)
Hereinafter, the operation when imaging the subject SU using the magnetic resonance imaging apparatus 1 of the present embodiment will be described.

  FIG. 2 is a flowchart showing an operation when imaging is performed on the subject SU in the embodiment according to the present invention.

  When imaging the subject SU, first, as shown in FIG. 2, the subject SU is placed on the placement surface of the cradle 15a (S11).

  FIG. 3 is a diagram illustrating an operation when the subject SU is placed on the placement surface of the cradle 15a in the embodiment according to the present invention. FIG. 3 shows a top view of the cradle 15a whose side surface is shown in FIG.

  As illustrated in FIG. 3, the cradle moving unit 15 b moves the cradle 15 a so that the cradle 15 a is positioned outside the imaging space B. Then, the subject SU is placed on the placement surface of the cradle 15a. For example, the subject SU, which is a human body, is instructed to lie on his back and the subject SU is placed.

  Here, in the cradle 15b moved to the imaging space B by the cradle moving unit 15b, the center position image IC indicating the position corresponding to the center position of the imaging space B is displayed on the placement surface of the cradle 15a by the light projection unit 25. A laser beam is projected to display. For example, by projecting red laser light, an image showing a cross shape is displayed as a center position image IC as shown in FIG. Then, alignment is performed by moving the subject SU so that the imaging region SA in which imaging is performed in the subject SU corresponds to the center position image IC. For example, alignment is performed by an operator giving a voice instruction to the subject SU, which is a human body.

  Next, as shown in FIG. 2, the receiving coil 14b is arranged so as to correspond to the imaging region of the subject SU (S21).

  FIG. 4 is a diagram showing an operation when the receiving coil 14b is arranged so as to correspond to the imaging region of the subject SU in the embodiment according to the present invention. FIG. 4 shows a view of the cradle 15a whose side surface is shown in FIG. FIG. 5 is a diagram showing a coil pattern of the receiving coil 14b in the embodiment according to the present invention. 5A is a perspective view, and FIG. 5B is a top view.

  As shown in FIG. 4, in a state where the cradle 15a is positioned outside the imaging space B, the receiving coil 14b is arranged on the placement surface of the cradle 15a so as to correspond to the imaging region of the subject SU. Here, the receiving coil 14b is installed in the cradle 15a so that the surface coil as shown in FIG. 5A is arranged on the subject F as shown in FIG. 5B.

  Thereafter, the light projection unit 25 projects the laser light so that the sensitivity distribution image KB indicating the sensitivity distribution of the receiving coil 14b arranged on the placement surface of the cradle 15a is displayed on the placement surface.

  Here, the light projection part 25 displays the image which divides | segments an area | region according to the sensitivity of the receiving coil 14b as the sensitivity distribution image KB. For example, as shown in FIG. 4, an image that divides the sensitivity range of the receiving coil 14b with a straight line is displayed as a sensitivity distribution image KB.

  Specifically, an area including the positional mark 14M provided in the reception coil 14b is imaged by an imaging device (not shown) such as a fixed camera to generate a digital image, and then the image data of the digital image is converted into the data processing unit 31. Receive. Then, the data processing unit 31 analyzes the digital image to calculate the positional information of the positional mark 14M. For example, the position information of the positional mark 14M is calculated from the pixel position of the image corresponding to the positional mark 14M. Thereafter, based on the positional information of the positional mark 14M provided on the receiving coil 14b, the control unit 30 controls the light projection unit 25 so as to correspond to the position of the receiving coil 14b disposed in the cradle 15a. The distribution image KB is displayed on the placement surface. That is, as shown in FIG. 4, the sensitivity distribution image KB is projected and displayed on the receiving coil 14b arranged in the cradle 15a.

  Here, the sensitivity distribution image KB is displayed so as to correspond to the type of the receiving coil 14b arranged in the imaging region of the subject SU.

  Specifically, when the receiving coil 14b is arranged, after the control unit 30 receives identification data for identifying the type from the receiving coil 14b, the sensitivity distribution image data corresponding to the types of the plurality of receiving coils 14b. Then, the sensitivity distribution image data corresponding to the received identification data is extracted. Then, based on the extracted sensitivity distribution image data, the control unit 30 performs control so that the light projection unit 25 projects the sensitivity distribution image.

  In the present embodiment, since the receiving coil 14b is a surface coil, as shown in FIG. 4, a straight line perpendicular to the body axis direction y is a body axis direction so as to partition the sensitivity region in the body axis direction y. The images arranged along y are displayed as a sensitivity distribution image KB. Here, as shown in FIG. 4, by projecting red laser light, the central portion in the body axis direction y is partitioned by a narrow region, and from the center portion toward the end side in the body axis direction y. Then, an image in which straight lines orthogonal to the body axis direction y are arranged along the body axis direction y so as to be divided into large areas sequentially is displayed as a sensitivity distribution image KB. That is, since the central portion has high sensitivity, for example, the distance between the straight lines is narrowed, and the sensitivity decreases as it goes to the end portion. Therefore, the sensitivity distribution image KB is set so that the distance between the straight lines is gradually increased. Is displayed.

  Then, after observing the sensitivity distribution image KB, the imaging region SA in which imaging is performed on the subject SU is moved so as to correspond to a region having high sensitivity in the sensitivity distribution image KB, thereby performing alignment.

  In the present embodiment, as described above, since the imaging region SA on which imaging is performed on the subject SU is aligned so as to correspond to the center position image IC, the sensitivity distribution is included in the center position image IC. The operator moves the receiving coil 14b so as to match a portion showing a region with high sensitivity in the image KB.

  Next, as shown in FIG. 2, the subject SU is scanned (S31).

  Here, after the operation data for starting the scan is input by the operator, the subject SU is placed on the placement surface as described above, and the cradle 15a in which the receiving coil 14b is placed on the placement surface. The cradle moving unit 15b moves to the imaging space B.

  In the present embodiment, the cradle 15a is moved so that the center position of the receiving coil 14b corresponds to the isocenter of the imaging space B. For example, the control unit 30 controls the movement operation of the cradle 15a based on the position information of the positional mark 14M calculated above and the identification data for identifying the type of the receiving coil 14b. Specifically, the control unit 30 calculates the center position of the receiving coil 14b arranged in the cradle 15a in the imaging space B from the position information of the positional mark 14M and the identification data for identifying the type of the receiving coil 14b. Then, based on the data on the center position of the receiving coil 14b arranged in the cradle 15a in the imaging space B and the data on the position of the isocenter in the imaging space B, the distance in the horizontal direction between the two positions is controlled. After the calculation by the unit 30, the cradle moving unit 15b moves the cradle 15a to the imaging space B so as to correspond to the calculated distance. Then, the scan unit 2 scans the imaging region of the subject SU so as to correspond to the set scan conditions, and collects magnetic resonance signals. After completion of the scan, the cradle 15a is moved from the inside of the imaging space B to the outside by the cradle moving unit 15b.

  Next, as shown in FIG. 2, a magnetic resonance image is generated (S41).

  Here, the data processing unit 31 uses the magnetic resonance signals collected above as raw data, and generates a magnetic resonance image for the imaging region of the subject SU. Specifically, the magnetic resonance image is reconstructed by performing inverse Fourier transform on the magnetic resonance signals collected so as to correspond to the k space.

  Next, as shown in FIG. 2, a magnetic resonance image is displayed (S51).

  Here, the display unit 33 receives the image data of the magnetic resonance image generated for the subject SU as described above from the data processing unit 31, and displays the magnetic resonance image on the display screen.

  As described above, the present embodiment includes the light projection unit 25 that projects light onto the placement surface of the cradle 15a, and the light projection unit 25 is a receiver disposed on the placement surface of the cradle 15a. Laser light is projected so that a sensitivity distribution image KB showing the sensitivity distribution of the coil 14b is displayed on the mounting surface before the scan is performed. Here, the light projection unit 25 displays this sensitivity distribution image when the cradle 15a is moved outside the imaging space B by the cradle moving unit 15b. For this reason, when arrange | positioning the receiving coil 14b, the position of the specific area | region where the sensitivity is high in the receiving coil 14b can be grasped clearly. Therefore, according to the present embodiment, it is easy to perform alignment with high accuracy, and thus it is possible to improve photographing efficiency.

  In the above embodiment, the magnetic resonance imaging apparatus 1 corresponds to the magnetic resonance imaging apparatus of the present invention. In the above embodiment, the receiving coil 14b corresponds to the RF coil of the present invention. In the above embodiment, the cradle 15a corresponds to the cradle of the present invention. Moreover, in said embodiment, the cradle moving part 15b is corresponded to the cradle moving part of this invention. Moreover, in said embodiment, the light projection part 25 is corresponded to the light projection part of this invention. Moreover, in said embodiment, the display part 33 is corresponded to the display part of this invention. In the above embodiment, the imaging space B corresponds to the static magnetic field space of the present invention.

  In implementing the present invention, the present invention is not limited to the above-described embodiment, and various modifications can be employed.

  For example, in the above embodiment, the case where the surface coil is arranged as the reception coil 14b has been described, but the present invention is not limited to this.

  For example, a loop coil or saddle coil for the body or head may be used. In addition, a phased array coil may be used.

  For example, when the loop coil for the body is arranged as the receiving coil 14b on the subject F, the loop coil for the body has the same shape as the surface coil shown in FIG. Similarly to the case, a straight line orthogonal to the body axis direction y is formed in the body axis direction y so that the area to be divided gradually increases from the central portion in the body axis direction y toward the end side in the body axis direction y. The images arranged along the lines are displayed as a sensitivity distribution image KB.

  FIG. 6 is a diagram showing a coil pattern of a saddle coil for a body in the embodiment according to the present invention. 6A is a perspective view, and FIG. 6B is a top view. FIG. 7 is a view showing a sensitivity distribution image displayed when the saddle coil for the body is arranged in the embodiment according to the present invention.

  Here, the saddle coil for the body as shown in FIG. 6A is arranged on the subject F as the receiving coil 14b as shown in FIG. 6B. When the body saddle coil, which is the receiving coil 14b, is arranged in the body portion of the subject SU, as shown in FIG. 7, the body is divided so that the regions partitioned in the body axis direction y are equally spaced from each other. An image in which straight lines orthogonal to the axial direction y are arranged along the body axial direction y is displayed as a sensitivity distribution image KB.

  FIG. 8 is a diagram showing a coil pattern of the QD loop and saddle coil for the head in the embodiment according to the present invention. 8A is a perspective view, and FIG. 8B is a top view. FIG. 9 is a diagram showing a sensitivity distribution image displayed when the loop and saddle coil for the head is arranged in the embodiment according to the present invention.

  Here, as shown in FIG. 8 (a), as shown in FIG. 8 (b), as shown in FIG. 8 (b), as shown in FIG. 8 (b), as shown in FIG. , Placed on the subject F. When the loop and saddle coil for the head, which is the receiving coil 14b, is arranged on the head of the subject SU, as shown in FIG. 9, the end in the body axis direction y from the central portion in the body axis direction y. An image in which straight lines orthogonal to the body axis direction y are arranged along the body axis direction y so as to narrow the area to be divided sequentially toward the part side is displayed as the sensitivity distribution image KB.

  FIG. 10 is a diagram showing a coil pattern of a phased array coil for a body in the embodiment according to the present invention. 10A is a perspective view, and FIG. 10B is a top view. FIG. 11 is a diagram showing a sensitivity distribution image to be displayed when the phased array coil for the body is arranged in the embodiment according to the present invention.

  Here, as shown in FIG. 10 (a), a phased array coil for a body in which a plurality of loop-shaped coils 14bra, 14brb, 14brc are arranged is a receiving coil 14b, as shown in FIG. 10 (b). , Placed on the subject F. Then, when the phased array coil for the body, which is the receiving coil 14b, is arranged in the body portion of the subject SU, as shown in FIG. 11, so as to correspond to the sensitivity of the plurality of coils 14bra, 14brb, 14brc. A sensitivity distribution image KB is displayed.

  In addition, in the above embodiment, the case where the RF coil unit 14 includes each of the transmission coil 14a and the reception coil 14b has been described. However, the present invention is not limited to this. The present invention can also be applied to a case where transmission and reception are performed by one RF coil.

  In the above embodiment, the position information of the positional mark 14M is calculated using a digital image captured by an imaging device (not shown) such as a fixed camera, so that the receiving coil 14b is placed on the mounting surface of the cradle 15a. Although the case where the arranged position is detected has been described, the present invention is not limited to this. For example, by using various sensors such as an optical position sensor, the position where the receiving coil 14b is arranged on the placement surface of the cradle 15a may be detected.

FIG. 1 is a configuration diagram showing a configuration of a magnetic resonance imaging apparatus 1 in an embodiment according to the present invention. FIG. 2 is a flowchart showing an operation when imaging is performed on the subject SU in the embodiment according to the present invention. FIG. 3 is a diagram illustrating an operation when the subject SU is placed on the placement surface of the cradle 15a in the embodiment according to the present invention. FIG. 4 is a diagram showing an operation when the receiving coil 14b is arranged so as to correspond to the imaging region of the subject SU in the embodiment according to the present invention. FIG. 5 is a diagram showing a coil pattern of the receiving coil 14b in the embodiment according to the present invention. FIG. 6 is a diagram showing a coil pattern of a saddle coil for a body in the embodiment according to the present invention. FIG. 7 is a diagram showing a sensitivity distribution image displayed when the saddle coil for the body is arranged in the embodiment according to the present invention. FIG. 8 is a diagram showing a coil pattern of the QD loop and saddle coil for the head in the embodiment according to the present invention. FIG. 9 is a diagram showing a sensitivity distribution image displayed when a loop coil or saddle coil for the head is arranged in the embodiment according to the present invention. FIG. 10 is a diagram showing a coil pattern of a phased array coil for a body in the embodiment according to the present invention. FIG. 11 is a diagram showing a sensitivity distribution image displayed when the phased array coil for the body is arranged in the embodiment according to the present invention.

Explanation of symbols

1: Magnetic resonance imaging apparatus (magnetic resonance imaging apparatus), 2: Scan unit, 3: Operation console unit, 12: Static magnetic field magnet unit, 13: Gradient coil unit, 14: RF coil unit, 14a: Transmitting coil, 14b: Receiving coil (RF coil), 15: subject moving unit, 15a: cradle (cradle), 15b: cradle moving unit (cradle moving unit), 22: RF driving unit, 23: gradient driving unit, 24: data collecting unit, 25: light projection unit (light projection unit), 30: control unit, 31: data processing unit, 32: operation unit, 33: display unit (display unit), 34: storage unit, B: imaging space (static magnetic field space)

Claims (9)

A magnetic resonance imaging apparatus that generates a magnetic resonance image for an imaging region by transmitting an RF pulse to an imaging region of a subject in a static magnetic field space and performing a scan that collects a magnetic resonance signal from the imaging region. ,
A cradle in which the subject is placed on the placement surface, and an RF coil is placed on the placement surface so as to correspond to an imaging region of the subject placed on the placement surface;
A light projection unit for projecting light on the mounting surface of the cradle,
The said light projection part projects the said light so that the sensitivity distribution image which shows the sensitivity distribution of RF coil arrange | positioned at the mounting surface of the said cradle may be displayed on the mounting surface mentioned above Magnetic resonance imaging apparatus. The light projection unit displays the sensitivity distribution image before the scan is performed.
The magnetic resonance imaging apparatus according to claim 1. The light projection unit is configured to project laser light as the light.
The magnetic resonance imaging apparatus according to claim 1 or 2. The light projection unit displays an image dividing a region according to the sensitivity of the RF coil as the sensitivity distribution image;
The magnetic resonance imaging apparatus according to claim 1. The light projection unit displays the sensitivity distribution image so as to correspond to the type of RF coil arranged in the imaging region of the subject.
The magnetic resonance imaging apparatus according to claim 1. A cradle moving part that moves the cradle between the inside and outside of the static magnetic field space;
The light projection unit displays the sensitivity distribution image when the cradle is moved outside the static magnetic field space by the cradle moving unit.
The magnetic resonance imaging apparatus according to claim 1. When the cradle is moved to the static magnetic field space by the cradle moving unit, the light projection unit displays a center position image indicating a position corresponding to the center position of the static magnetic field space in the cradle. Projecting the light to display on a surface;
The magnetic resonance imaging apparatus according to claim 6. The light projection unit displays the center position image when the cradle is moved outside the static magnetic field space by the cradle moving unit.
The magnetic resonance imaging apparatus according to claim 7. A display unit for displaying the magnetic resonance image on a screen;
The magnetic resonance imaging apparatus according to claim 1.

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