RF coil device and medical imaging diagnostic device

Abstract

The objective is to provide an RF coil device, which can be attached to a subject used in an environment with a magnetic field, that allows for position adjustment while the subject is moved inside the mounting device. [Solution] The RF coil device of the embodiment is an RF coil device that receives electromagnetic waves emitted from a subject in response to an RF pulse irradiated onto the subject under the influence of a magnetic field, and comprises a plurality of RF coil elements, a holding mechanism, and an outer casing. The plurality of RF coil elements are arranged in a planar manner. A non-conductive fluid flows into or out of the holding mechanism from a fluid path. The outer casing houses the plurality of RF coil elements and the holding mechanism. Each of the RF coil elements is positioned on the surface of the outer casing on the side that the outer casing contacts the subject, and the holding mechanism is positioned on the surface of the outer casing on the side opposite to the side that the outer casing contacts the subject.

Description

Technical Field

[0004] , , , , ,

[0003]

[0001] Embodiments of the present invention relate to an RF coil device and a medical imaging diagnostic apparatus.

Background Art

[0002] Conventionally, a magnetic resonance imaging (MRI) device has been used as a medical imaging diagnostic apparatus for performing diagnosis by images. An MRI device (hereinafter referred to as an "MRI device") is a device that images a tomographic image of a subject by receiving an MR signal excited by an RF (Radio Frequency) pulse irradiated in a strong magnetic field with an RF coil. Conventionally, when imaging a tomographic image of a subject with an MRI device, as an RF coil for receiving an MR signal, for example, an RF coil having a structure that can be attached to the subject, so-called a local coil, has also been used.

[0003] When imaging a tomographic image of a subject with an MRI device, the subject is placed on the top plate of a bed device, a local coil is attached to the subject, and the entire top plate with the subject is moved into the interior of a gantry device having components for generating a magnetic field in this state, that is, into the bore of the gantry device. At this time, an operator (such as a doctor or a technician) of the MRI examination attaches the local coil to the subject so that the imaging target part of the subject is in a suitable position in the generated magnetic field, that is, in a position suitable for imaging, and moves the top plate. ​​However, it is possible that the position of the local coil attached to the subject may become unsuitable for acquiring a suitable tomographic image, for example, if the local coil becomes displaced while the tabletop is being moved. Such displacement of the local coil cannot be determined without performing imaging with an MRI device. Moreover, because MRI devices use a strong magnetic field to acquire tomographic images, it is difficult to configure a device that incorporates a mechanism to apply external mechanical force using components such as switches or motors to adjust the displacement of the local coil. For this reason, conventionally, the person performing the MRI examination had to move the tabletop again to pull the subject out of the bore of the rigging device, reattach the local coil, and then move the tabletop again to put the subject back into the bore of the rigging device before performing tomographic imaging again.

[0005] For this reason, technologies have been proposed to enable the local coil to be mounted in a suitable position without using electrical mechanisms. However, even with conventional technologies, it is difficult to adjust the positional displacement of the local coil within the bore of the mounting device. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 8-257006 [Patent Document 2] Japanese Patent Publication No. 2014-073294 [Patent Document 3] Special Publication No. 2022-503655 [Patent Document 4] Japanese Patent Publication No. 2011-030828 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The problem that the embodiments disclosed herein and in the drawings aim to solve is to enable adjustment of the position of an RF coil device, which is designed to be attached to a subject used in an environment where a magnetic field is present, while the subject has been moved inside the mounting device. However, the problem that the embodiments disclosed herein and in the drawings aim to solve is not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described later can also be positioned as other problems. [Means for solving the problem]

[0008] The RF coil device of the embodiment is an RF coil device that receives electromagnetic waves emitted from a subject in response to an RF pulse irradiated onto the subject under the influence of a magnetic field, and comprises a plurality of RF coil elements, a holding mechanism, and an outer casing. The plurality of RF coil elements are arranged in a planar manner. A non-conductive fluid flows into or out of the holding mechanism from a fluid path. The outer casing houses the plurality of RF coil elements and the holding mechanism. Each of the RF coil elements is positioned on the surface of the outer casing on the side that the outer casing contacts the subject, and the holding mechanism is positioned on the surface of the outer casing on the side opposite to the side that the outer casing contacts the subject. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram showing an example of the installation state of a medical imaging diagnostic device employing an RF coil device according to the embodiment. [Figure 2] A diagram showing an example of the configuration of a medical imaging diagnostic device employing an RF coil device according to the embodiment. [Figure 3] A schematic diagram showing the configuration of an RF coil device according to an embodiment, and an example of how the RF coil device is attached to a subject. [Figure 4] A schematic diagram showing other configurations of the RF coil device according to the embodiment, and an example of the RF coil device being attached to a subject. [Figure 5] A schematic diagram showing another example of the structure of the holding mechanism provided in the RF coil device according to the embodiment. [Modes for carrying out the invention]

[0010] The RF coil device of the embodiment and the medical imaging diagnostic device employing the RF coil device will be described below with reference to the drawings. In the following description, the medical imaging diagnostic device employing the RF coil device of the embodiment will be assumed to be a magnetic resonance imaging (MRI) device (hereinafter referred to as "MRI device").

[0011] An MRI machine is a medical imaging diagnostic device that applies a strong magnetic field to a subject (e.g., the human body) and irradiates it with RF (Radio Frequency) pulses. Electromagnetic waves generated from hydrogen nuclei within the subject's body due to the nuclear magnetic resonance phenomenon are received by an RF coil. The MRI machine then reconstructs the nuclear magnetic resonance signal (hereinafter referred to as the "MR signal") based on the received electromagnetic waves to acquire a tomographic image (hereinafter referred to as the "MR image"). An MRI machine can also acquire an MR image of a subject by reconstructing the MR signal based on the electromagnetic waves received by an RF coil attached to the subject. By displaying the MR image of the subject, the person performing the MRI examination (such as a doctor or technician) can visually confirm whether or not there are lesions in the subject.

[0012] Figure 1 is a schematic diagram showing an example of the installation of a medical imaging diagnostic device (MRI device) employing an RF coil device according to an embodiment. In the example shown in Figure 1, for example, a patient bed device 20 equipped with a tabletop on which the subject P to be examined is placed, and a stand device 10 that generates a magnetic field to image the subject P, irradiates the subject P with RF pulses, and receives MR signals are installed in the imaging room PR. Furthermore, in the example shown in Figure 1, for example, a console device 40 for the person performing the MRI examination (such as a doctor or technician) to operate and give instructions during imaging of the subject P is installed in the control room OR, and devices such as a control device 30 and a mechanical device 60 that control the operation of the stand device 10 and the patient bed device 20 in response to instructions from the console device 40 are installed in the machine room MR. In Figure 1, the imaging room PR is a shielded room so that the magnetic field generated by the stand device 10 does not leak into the control room OR or the machine room MR. As a result, in the example shown in Figure 1, only the imaging room PR is an environment (magnetic field environment) where the magnetic field generated by the stand device 10 exists. The components that make up the MRI machines installed in each room are electrically connected to each other, for example, by cables.

[0013] Figure 2 shows an example of the configuration of a medical imaging diagnostic device (MRI device) employing an RF coil device according to the embodiment. The MRI device 1 includes, for example, a pedestal device 10, a patient bed device 20, a control device 30, a console device 40, and a mechanical device 60. In this embodiment, the control device 30 and the console device 40 are described as being separate from the pedestal device 10, but the pedestal device 10 may include some or all of the components of the control device 30 and the console device 40.

[0014] The rigging device 10 includes, for example, a static magnetic field magnet 12, a gradient magnetic field coil 14, and an RF coil 16. Furthermore, the rigging device 10 includes, for example, an RF coil 17 that can be attached to the subject P as a component of the RF coil 16.

[0015] The static magnetic field magnet 12 is a magnet formed in a hollow, approximately cylindrical shape. The static magnetic field magnet 12 generates a uniform static magnetic field in its internal space. The static magnetic field magnet 12 can be, for example, a permanent magnet or a superconducting magnet. If the static magnetic field magnet 12 is a superconducting magnet, it generates a static magnetic field by receiving power from a static magnetic field power source (not shown).

[0016] The gradient coil 14 is a hollow, substantially cylindrical coil. The gradient coil 14 is positioned inside the static magnetic field magnet 12. The gradient coil 14 is formed by combining three coils corresponding to the mutually orthogonal X, Y, and Z axes. Each of the three coils corresponding to the direction of each axis receives current individually from the gradient power supply 32, generating a gradient magnetic field in the imaging space (i.e., inside the bore) of the MRI device 1 into which the subject P is introduced, with the magnetic field strength changing along the X, Y, and Z axes. In this embodiment, the central axis of the rigging device 10 or the longitudinal direction of the top plate 24 of the patient device 20 is defined as the Y-axis direction, the axis horizontal to the floor of the room in which the MRI device 1 is installed is defined as the X-axis direction, the axis perpendicular to the Y-axis direction is defined as the X-axis direction, the axis perpendicular to the Y-axis direction is defined as the X-axis direction, the axis perpendicular to the floor is defined as the Y-axis direction, and the direction perpendicular to the floor is defined as the Z-axis direction. In this embodiment, the Y-axis direction is the same direction as the static magnetic field.

[0017] Here, the gradient magnetic fields generated by the gradient coil 14 along the X, Y, and Z axes correspond to, for example, a slice selection gradient magnetic field, a phase encoding gradient magnetic field, and a readout gradient magnetic field, respectively. The slice selection gradient magnetic field is used to determine an arbitrary imaging cross-section in the MRI device 1. The phase encoding gradient magnetic field is used to change the phase of the MR signal according to the spatial position in the MRI device 1. The readout gradient magnetic field is used to change the frequency of the MR signal according to the spatial position in the MRI device 1.

[0018] The RF coil 16 is a whole-body coil housed within the gantry device 10 and configured to surround the subject P within the imaging space. The RF coil 16 includes a transmission coil that receives the supply of RF pulses from the transmission circuit 33 and generates a high-frequency magnetic field, and a reception coil that receives the MR signal emitted from the subject P under the influence of the high-frequency magnetic field. When the reception coil of the RF coil 16 receives an MR signal, it outputs the received MR signal to the reception circuit 34. The RF coil 16 may be configured with different coils for the transmission coil and the reception coil, or may be configured with the same coil, that is, a coil that can be used for both transmission and reception. In this case, the RF coil 16 may be, for example, a birdcage coil.

[0019] The RF coil 17 is a local coil attached to the subject P. There are various shapes of the RF coil 17 for each imaging target site (hereinafter referred to as "imaging site") of the subject P. FIG. 1 shows an example of the RF coil 17 attached to the torso of the subject P. The RF coil 17 receives the MR signal emitted from the subject P under the influence of the high-frequency magnetic field generated by the RF coil 16. As a reception coil for receiving the MR signal, for example, a plurality of coil elements are arranged planar within the range of the corresponding imaging site. The RF coil 17 may be, for example, a coil array composed of a plurality of coil elements. When the RF coil 17 receives an MR signal, it outputs the received MR signal to the reception circuit 34. The RF coil 17 may be a wired type that outputs the received MR signal to the reception circuit 34 by wire, or a wireless type that outputs (transmits) the received MR signal to the reception circuit 34 wirelessly. FIG. 1 shows an example of a wired RF coil 17 that outputs the MR signal received via the coil cable 17c connected to the coil port 26 arranged on the top plate 24 to the reception circuit 34.

[0020] The RF coil 17 includes a mechanism (hereinafter referred to as the "holding mechanism") for holding (fixing) the subject P (more specifically, the imaging region) in a suitable position when mounted, and for adjusting the degree of adhesion of the coil element to the subject P (increasing or decreasing the degree of adhesion). Here, the coil element being in close contact with the subject P (increasing the degree of adhesion) means that the distance between the coil element and the subject P becomes shorter. The holding mechanism, for example, holds the imaging region or brings the coil element into close contact with the subject P by flowing a fluid into or out of a bag body to change the volume of the space (region where the fluid is contained) inside the bag body. That is, the holding mechanism changes the holding force (which can also be said to be the fixing force for fixing the imaging region) for holding the imaging region by the inflation or contraction of the bag body by the fluid, and changes the degree of adhesion of the coil element to the subject P. The fluid is, for example, a gas or a liquid made of a material with low conductivity (less affected by a magnetic field), that is, a non-conductive material. The fluid path for flowing the fluid into and out of the bag body of the holding mechanism includes, for example, a flexible pipe. The fluid path (hereinafter referred to as the "fluid pipe") may be connected to the coil port 26 together with the coil cable 17c, or may be connected to a port (not shown) different from the coil port 26. FIG. 1 shows an example of flowing the fluid into and out of the holding mechanism (bag body) from the fluid inlet / outlet 61 via the fluid pipe 17p connected to the coil port 26 together with the coil cable 17c. Details of the configuration of the RF coil 17 will be described later.

[0021] The RF coil 17 is an example of an "RF coil device".

[0022] The bed device 20 is a device for introducing the subject P on which the imaging target is placed into the inside of the gantry device 10, that is, into the bore of the gantry device 10, by moving the top plate 24 on which the subject P is placed. In other words, the bed device 20 is a device for moving the top plate 24 so that the imaging region of the subject P is in a position suitable for imaging in the magnetic field generated inside the cavities of the static magnetic field magnet 12, the gradient magnetic field coil 14, and the RF coil 16, that is, inside the imaging aperture. The bed device 20 includes, for example, a base 22 and a top plate 24.

[0023] The base 22 moves the tabletop 24 on which the subject P is placed horizontally (in the X-axis and Y-axis directions) or vertically (in the Z-axis direction) by the operation of a table drive device (not shown) which operates in response to a control signal output by the table control circuit 35. The base 22 includes a housing that movably supports the tabletop 24. The table drive device (not shown) includes, for example, a motor or actuator. The table drive device (not shown) may move not only the tabletop 24 but also the base 22 itself in the longitudinal direction (Y-axis direction) of the tabletop 24. If the support device 10 is configured to move in the Y-axis direction, the table drive device (not shown) may also operate to move the support device 10 so that the subject P is introduced into the support device 10. If the bed drive device (not shown) is configured such that both the frame device 10 and the top plate 24 and base 22 are movable, it may operate by moving the frame device 10, the top plate 24, and the base 22 respectively so that the subject P is introduced into the frame device 10.

[0024] The top plate 24 is a plate-shaped member on which the subject P is placed. The top plate 24 is made of a non-conductive material, such as glass fiber. Coil ports 26 are arranged on the top plate 24 to which the coil cable 17c and fluid pipe 17p of the RF coil 17 attached to the subject P are connected. For example, coil ports 26 are arranged on the top plate 24 at the four corners.

[0025] The control device 30 controls the operation of the frame device 10 and the bed device 20 in response to control from the console device 40. The control device 30 includes, for example, a sequence control circuit 31, a gradient magnetic field power supply 32, a transmitting circuit 33, a receiving circuit 34, and a bed control circuit 35. Figure 1 shows the control device 30 located in the machine room MR, but some or all of the components of the control device 30 may be located in the frame device 10 or in the console device 40.

[0026] The sequence control circuit 31 is a sequencer that performs imaging of the subject P by driving the gradient power supply 32, the transmitting circuit 33, and the receiving circuit 34 based on sequence information set by the console device 40. The sequence control circuit 31 may be a processing circuit having a processor such as a CPU (Central Processing Unit). The sequence information is information that defines the procedure for performing imaging processing to image the subject P in the MRI device 1. The sequence information is defined in advance for each imaging process performed in the MRI device 1. For example, the sequence information shows the operation and timing of the operation of the gradient power supply 32, the transmitting circuit 33, and the receiving circuit 34 when imaging the subject P in chronological order (hereinafter referred to as "events"). More specifically, the sequence information indicates events such as the magnitude and timing of the current supplied to the gradient coil 14 by the gradient power supply 32, the strength and timing of the RF pulses transmitted (supplied) to the RF coil 16 by the transmitting circuit 33, and the timing of the RF pulse supply to the receiving circuit 34 to receive (detect) the MR signals output by the RF coil 16 and RF coil 17. The sequence control circuit 31 drives the gradient power supply 32, the transmitting circuit 33, and the receiving circuit 34 by sequentially executing the events indicated in the sequence information at timings based on a predetermined clock signal. When the receiving circuit 34 receives the MR signal, it transfers the received MR signal to the console device 40. The clock signal is generated, for example, by a clock generation circuit (not shown) including a clock oscillator, and represents the timing used as a reference for the operation of imaging the subject P in the MRI device 1. The clock signal is supplied to each component of the control device 30. The sequence control circuit 31 executes events in sequence based on the timing of the clock signal, causing the gradient power supply 32, the transmitting circuit 33, and the receiving circuit 34 to operate in synchronous manner.

[0027] The gradient power supply 32 supplies current individually to each of the three coils in the gradient coil 14, corresponding to the direction of each axis.

[0028] The transmitting circuit 33 supplies RF pulses to the RF coil 16. The RF pulses supplied by the transmitting circuit 33 to the RF coil 16 are pulses corresponding to the Larmor frequency, which is determined by the type of atomic nucleus being targeted and the strength of the magnetic field.

[0029] The receiving circuit 34 detects the MR signal output by the RF coil 16 and RF coil 17 and generates data representing the detected MR signal (hereinafter referred to as "MR data"). The receiving circuit 34 generates the MR data by, for example, converting the MR signal into digital data of digital values. The receiving circuit 34 outputs the generated MR data to the sequence control circuit 31. The sequence control circuit 31 transfers the MR data output by the receiving circuit 34 to the console device 40.

[0030] The bed control circuit 35 outputs a control signal to a bed drive device (not shown) provided in the bed device 20 that moves the base 22 and the top plate 24 on which the subject P is placed, in response to control from the console device 40. The bed control circuit 35 may be provided in the pedestal device 10 or in the bed device 20. In this case, the bed control circuit 35 outputs a control signal to a bed drive device (not shown) provided in the bed device 20 that corresponds to an input signal input from an input interface (not shown) provided in the device in which the bed control circuit 35 is provided, when the operator of the MRI device 1, such as a doctor or technician, or the person performing the MRI examination (hereinafter referred to as "the person performing the MRI examination") operates the input interface (not shown) provided in the device in which the bed control circuit 35 is provided, in response to an input signal input from the input interface (not shown).

[0031] The console device 40 controls the entire MRI device 1 and collects MR data. The console device 40 includes, for example, a memory 41, a display 42, an input interface 43, and a processing circuit 50.

[0032] Memory 41 can be implemented using semiconductor memory elements such as ROM (Read Only Memory), RAM (Random Access Memory), or flash memory, or by a hard disk drive (HDD), optical disc, etc. Memory 41 stores data such as MR data output by the sequence control circuit 31 and reconstructed images (MR images) generated based on the MR data. This data may be stored in an external memory that the MRI device 1 can communicate with, rather than in memory 41 (or in addition to memory 41). The external memory may be a NAS (Network Attached Storage) or a cloud server that manages the external memory and accepts read / write requests, and is controlled by the cloud server. The external memory can be implemented using a system called PACS (Picture Archiving and Communication Systems). PACS is a medical image management system that systematically stores medical images acquired by various medical imaging diagnostic devices.

[0033] The display 42 displays various types of information. For example, the display 42 displays medical images generated by the processing circuit 50, or GUI (Graphical User Interface) images that accept various operations from the person performing the MRI examination. The display 42 may be, for example, a liquid crystal display (LCD), a CRT (Cathode Ray Tube) display, or an organic EL (Electroluminescence) display. The display 42 may be mounted on the stand device 10. The display 42 may be a desktop type, or it may be a display device (for example, a tablet terminal) that can communicate wirelessly with the main unit of the console device 40.

[0034] The input interface 43 receives various input operations from the MRI examiner and outputs an electrical signal indicating the content of the received input operation to the processing circuit 50. For example, the input interface 43 receives input operations such as the acquisition conditions when acquiring MR data, the generation conditions when generating MR data, the reconstruction conditions when reconstructing reconstructed images, the image processing conditions when generating post-processed images from reconstructed images, and the operation of flowing fluid into and out of the bag of the holding mechanism of the RF coil 17. The input interface 43 can be implemented by, for example, a mouse, keyboard, touch panel, trackball, switch, button, joystick, camera, infrared sensor, microphone, etc. If the input interface 43 is a touch panel, the display 42 may be formed integrally with the input interface 43. The input interface 43 may be provided on the rigging device 10. The input interface 43 may be implemented by a display device (e.g., a tablet terminal) that can communicate wirelessly with the main body of the console device 40. In this specification, the input interface 43 is not limited to those equipped with physical operating components such as the mouse and keyboard described above. For example, an electrical signal processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the console device 40 and outputs this electrical signal to the processing circuit 50 is also an example of an input interface 43.

[0035] The processing circuit 50 controls the overall operation of the MRI device 1. The processing circuit 50 sets sequence information in the sequence control circuit 31. For example, when acquiring an MR image of a subject P in the MRI device 1, the processing circuit 50 sets sequence information corresponding to the MR image acquisition process in the sequence control circuit 31. The processing circuit 50 performs functions such as acquisition function 51, reconstruction processing function 52, image processing function 53, output control function 54, and fluid control function 55. The processing circuit 50 realizes these functions, for example, by having a hardware processor provided in a computer device execute a program (software) stored in a memory 41, which is a memory device (storage circuit).

[0036] A hardware processor refers to circuits such as CPUs, GPUs (Graphics Processing Units), LSIs (Large Scale Integration), SOCs (System on Chips), Application Specific Integrated Circuits (ASICs), and programmable logic devices (e.g., Simple Programmable Logic Devices (SPLDs), Complex Programmable Logic Devices (CPLDs), Field Programmable Gate Arrays (FPGAs)). Instead of storing the program in memory 41, the hardware processor may be configured to directly embed the program within its circuitry. In this case, the hardware processor performs its functions by reading and executing the program embedded within the circuitry. A hardware processor is not limited to being configured as a single circuit; it may also be configured as a single hardware processor by combining multiple independent circuits to implement each function. Multiple components may be integrated into a single hardware processor to implement each function. Multiple components may be incorporated into a single dedicated LSI to implement each function. Here, the program (software) may be stored in advance in a storage device that constitutes memory 41, such as a semiconductor memory element like ROM, RAM, or flash memory, or a hard disk drive (HDD) (a storage device equipped with a non-transient storage medium), or it may be stored in a removable storage medium (non-transient storage medium) such as a DVD or CD-ROM, and installed in the storage device of the console device 40 when the storage medium is inserted into a drive device provided in the console device 40. The program (software) may also be downloaded in advance from another computer device via a network (not shown) and installed in the storage device of the console device 40.

[0037] Each component of the console device 40 or the processing circuit 50 may be distributed and implemented by multiple hardware components. The processing circuit 50 may not be implemented in the configuration of the console device 40, but rather by a processing unit that can communicate with the console device 40. The processing unit may be, for example, a workstation connected to one MRI device, or a device connected to multiple MRI devices that performs processing equivalent to that of the processing circuit 50 described below (e.g., a cloud server). In other words, the configuration of this embodiment can also be implemented as an MRI examination system (medical diagnostic system) in which the MRI device and other processing units are connected via a network not shown.

[0038] The acquisition function 51 acquires the MR data transferred by the sequence control circuit 31. The MR data is obtained by converting the MR signal into digital data by the receiving circuit 34. The acquisition function 51 stores the acquired MR data in the memory 41.

[0039] The reconstruction processing function 52 performs a predetermined reconstruction process on the MR data acquired by the acquisition function 51 (which may also be MR data stored in memory 41) to generate a reconstructed image. For example, the reconstruction processing function 52 arranges the MR data in two or three dimensions corresponding to the gradient magnetic field for slice selection, the gradient magnetic field for phase encoding, and the gradient magnetic field for readout, and then performs a reconstruction process using Fourier transform or the like to generate a reconstructed image. The reconstruction processing function 52 stores the generated reconstructed image in memory 41.

[0040] The image processing function 53 generates an MR image for presentation to the MRI examiner by applying predetermined image processing to the reconstructed image stored in the memory 41 based on the input operation received by the input interface 43. The predetermined image processing is, for example, a process of converting the reconstructed image into a three-dimensional image or cross-sectional image data of an arbitrary cross-section using a known method. The image processing function 53 stores the generated MR image in the memory 41.

[0041] The output control function 54 controls, for example, the display mode on the display 42. The output control function 54 outputs and displays the MR image generated by the image processing function 53 and stored in the memory 41 on the display 42. This allows the MRI examiner to visually confirm the MR image displayed on the display 42 and perform diagnoses and examinations such as confirming the attachment status of the RF coil 17 to the subject P and whether or not there is a lesion in the subject P. Confirming the attachment status of the RF coil 17 to the subject P is done, for example, by determining whether the RF coil 17 is attached in a suitable position and whether or not the coil element is in close contact with the imaging site so that a suitable MR image can be acquired (whether or not the level of electromagnetic waves received by the RF coil 17 has reached a level that can reconstruct a suitable MR image), based on the MR image obtained from imaging performed prior to (in advance of) the MRI examination of the subject P. The output control function 54 may also transmit the MR image to, for example, a tablet terminal connected to the main body of the console device 40 via a network (not shown) and display it on the display device. The output control function 54 may display GUI images or the like to accept various operations from the person performing the MRI examination.

[0042] The fluid control function 55 controls the amount of fluid that the fluid inlet / outlet device 61 allows to flow into and out of the holding mechanism (bag) of the RF coil 17, in response to an input operation received by the input interface 43 that causes fluid to flow into and out of the holding mechanism (bag) of the RF coil 17. The fluid control function 55 outputs a control signal (hereinafter referred to as the "fluid inlet / outlet control signal") for controlling the inlet and outlet of fluid to the fluid inlet / outlet device 61.

[0043] The mechanical device 60 controls, at least, the inflow and outflow of fluid into the holding mechanism (bag) of the RF coil 17 in response to control from the console device 40. The mechanical device 60 includes, for example, a fluid inflow / outflow device 61.

[0044] The fluid inlet / outlet device 61 causes fluid to flow into and out of the fluid pipe 17p, in accordance with the fluid inlet / outlet control signal output by the fluid control function 55 executed in the processing circuit 50 within the console device 40, thereby causing fluid to flow into and out of the bag-shaped body of the RF coil 17. In other words, the fluid inlet / outlet device 61 causes fluid to flow into and out of the bag-shaped body of the holding mechanism, moves the fluid within the bag-shaped body of the holding mechanism, circulates the fluid within the bag-shaped body of the holding mechanism, and discharges (outflows) the fluid from the bag-shaped body of the holding mechanism by causing fluid to flow into and out of the fluid pipe 17p.

[0045] MRI device 1 is an example of a "medical imaging diagnostic device." The configuration combining the fluid control function 55 and the mechanical device 60 (more specifically, the fluid inlet / outlet device 61) is an example of a "control unit."

[0046] [An example of the configuration of an RF coil device (local coil)] Next, an example of the configuration of the RF coil 17 (local coil) used in the MRI device 1 will be described. Figure 3 is a schematic diagram showing the configuration of the RF coil device (RF coil 17) according to the embodiment, and an example of the RF coil device (RF coil 17) being attached to the subject P. Figure 3(a) shows an example of a cross-section at an arbitrary position of the basic configuration of the RF coil 17, and Figure 3(b) shows an example of a cross-section at an arbitrary position when the RF coil 17 is attached to the subject P.

[0047] First, an example of the basic configuration of the RF coil 17 will be explained using Figure 3(a). The RF coil 17 has multiple coil elements Ce connected to a coil cable 17c and a bag body 17b through which fluid flows in and out via a fluid pipe 17p, all housed in the RF coil housing 17o (so-called housing). Inside the RF coil housing 17o, each coil element Ce is positioned between the imaging area of ​​the subject P and the bag body 17b; that is, each coil element Ce is positioned on the side that contacts the imaging area of ​​the subject P. A coil cable connection mechanism 17cm for connecting to a coil port 26 is provided at the end of the coil cable 17c opposite to the coil element Ce. A fluid pipe connection mechanism 17pm for connecting to a coil port 26 is provided at the end of the fluid pipe 17p opposite to the bag body 17b. With this configuration, the RF coil 17 allows fluid to flow from the fluid inlet / outlet 61 into the bag body 17b via the coil port 26 and the fluid pipe 17p. As a result, in the RF coil 17, the bag 17b expands due to the inflowing fluid, increasing the degree of contact between the coil element Ce and the imaging area of ​​the subject P. Moreover, the expansion of the bag 17b in the RF coil 17 increases the holding force of the imaging area of ​​the subject P, that is, the imaging area becomes more fixed.

[0048] Next, an example of attaching the RF coil 17 to the subject P will be explained using Figure 3(b). The example of attaching the RF coil 17 shown in Figure 3(b) is an example of attaching the RF coil 17 to the torso (trunk) of the subject P, as shown in Figure 1. In the example of attachment shown in Figure 3(b), the illustration of the coil cable 17c, coil cable connection mechanism 17cm, fluid pipe 17p, and fluid pipe connection mechanism 17pm of the RF coil 17 is omitted for the sake of simplicity of explanation. In the example of attachment shown in Figure 3(b), the RF coil housing 17o of the RF coil 17 is attached to the subject P using the subject fixing part 24f provided on the top plate 24 for restraining (fixing) the subject P to the top plate 24. More specifically, in the mounting example shown in Figure 3(b), the RF coil housing 17o of the RF coil 17 is placed on the torso (imaging area) of the subject P, and the subject fixing parts 24f surrounding the subject P from the left and right are fixed with the attachment / detachment parts 24v. In other words, the RF coil housing 17o of the RF coil 17 is fixed together with the subject P, thereby mounting the RF coil housing 17o of the RF coil 17 to the subject P. At this time, the RF coil housing 17o of the RF coil 17 may be placed on the torso (imaging area) of the subject P while it is in a cover, such as a bag into which the RF coil housing 17o is inserted. The subject fixing parts 24f are guides for fixing the RF coil housing 17o and the subject P. The subject fixing parts 24f are, for example, fixing bands with a certain width. The attachment / detachment parts 24v are, for example, hook-and-loop fasteners that facilitate the attachment and detachment of the left and right subject fixing parts 24f (fixing bands) at predetermined positions (predetermined surfaces). As a result, in the RF coil 17, when the bag 17b expands due to the fluid, the side of the bag 17b opposite to the subject P is held down by the respective subject fixing parts 24f, causing it to expand more toward the subject P, thereby increasing the degree of contact between the coil element Ce and the imaging area of ​​the subject P (including increasing the holding force of the subject P).

[0049] The coil element Ce is an example of an "RF coil element," the bag 17b is an example of a "holding mechanism," and the RF coil housing 17o is an example of an "outer casing." The fluid pipe 17p (which may include the fluid pipe connection mechanism 17pm) is an example of a "fluid path." The coil cable 17c (which may include the coil cable connection mechanism 17cm) is an example of a "signal output cable."

[0050] [Another example of an RF coil device (local coil)] By the way, as mentioned above, the RF coil 17 (local coil) comes in various shapes depending on the imaging area of ​​the subject P. Here, we will describe an example of a different shape of the RF coil 17. Figure 4 is a schematic diagram showing other configurations of the RF coil device (RF coil 17) according to the embodiment, and an example of when the RF coil device (RF coil 17) is attached to the subject P. Figure 4(a) shows the configuration of the head RF coil 17 attached to the head of the subject P, and an example of a cross-section at an arbitrary position when this head RF coil 17 (hereinafter referred to as "head RF coil 17h") is attached to the subject P. Figures 4(b) and 4(c) show the configuration of the limb RF coil 17 attached to the limbs of the subject P, and an example of a cross-section at an arbitrary position when this limb RF coil 17 (hereinafter referred to as "limb RF coil 17e") is attached to the subject P. Figure 4(b) shows an example of a limb RF coil 17 (hereinafter referred to as "wrist RF coil 17w") that is attached, for example, to the wrist (radiocarpal joint) of subject P, and Figure 4(c) shows an example of a limb RF coil 17 (hereinafter referred to as "thigh RF coil 17t") that is attached, for example, to the thigh of subject P.

[0051] The head RF coil 17h shown in Figure 4(a) has a configuration in which the RF coil housings 17o of two RF coils 17 are housed in a housing (which is also a so-called housing) formed to surround the head of the subject P, and the coil cables 17c and fluid pipes 17p of each RF coil 17 are routed out from holes provided in the housing. The housing is a guide that realizes the function of fixing the subject P (more specifically, the head of the subject P) to the RF coil housing 17o of the RF coil 17, as shown in the subject fixing part 24f shown in Figure 3(b). In the following description, the housing of the head RF coil 17h will be referred to as the "fixing guide 17g". In Figure 4(a), the RF coils 17 housed in the fixing guide 17g are distinguished, with the RF coil 17 on the face side being shown as "RF coil 17-1" and the RF coil 17 on the back of the head side being shown as "RF coil 17-2". Furthermore, in Figure 4(a), to distinguish the components of each RF coil 17, a hyphen "-" followed by a number is added after each symbol. In the head RF coil 17h, the RF coil housing 17o-1 is provided with holes 17a for allowing air, light, and sound to pass through, in order to prevent the eyes, nose, mouth, and ears (not shown) of the subject P from being blocked by the RF coil housing 17o-1. With this configuration, even with the head RF coil 17h, when one or both of the bag bodies 17b (bag body 17b-1 and / or bag body 17b-2) of the RF coil housing 17o-1 and RF coil housing 17o-2 expand due to the fluid flowing in from the fluid inlet / outlet 61, the surface of the bag body 17b opposite to the subject P is held down by the fixing guide 17g, thereby increasing the degree of contact between the coil element Ce (coil element Ce-1 and / or coil element Ce-2) and the subject P's head (imaging area) (including increasing the holding force of the subject P's head).

[0052] In the head RF coil 17h shown in Figure 4(a), two RF coils 17, RF coil 17-1 and RF coil 17-2, are housed within the fixing guide 17g. However, the number of RF coils 17 housed within the fixing guide 17g in the head RF coil 17h is not limited to two. For example, the head RF coil 17h may have a configuration in which a single RF coil 17 is housed within the fixing guide 17g.

[0053] The wrist RF coil 17w shown in Figure 4(b) has a configuration in which an RF coil housing 17o of one RF coil 17 is housed within a fixing guide 17g and fixing guide band 17gb (which are also known as a housing) formed to surround a part of the subject P's wrist. In the wrist RF coil 17w shown in Figure 4(b), the illustration of the RF coil cable 17c, coil cable connection mechanism 17cm, fluid pipe 17p, and fluid pipe connection mechanism 17pm of the RF coil 17 has been omitted for the sake of simplicity of explanation. In the wrist RF coil 17w, the fixing guide 17g and fixing guide band 17gb are fixed by a detachable part 17v. The detachable part 17v is a fastener, such as hook-and-loop fastener, that allows for easy attachment and detachment of the fixing guide 17g and fixing guide band 17gb. With this configuration, even with the wrist RF coil 17w, when the bag 17b of the RF coil housing 17o expands due to the fluid flowing in from the fluid inlet / outlet 61, the surface of the bag 17b opposite to the subject P is held down by the fixing guide 17g, which increases the degree of contact between the coil element Ce and the subject P's wrist (imaging area) (including increasing the holding force of the subject P's wrist).

[0054] The RF coil 17t for the thigh shown in Figure 4(c) consists of a fixing guide 17g formed to surround a part of the thigh of the subject P and an RF coil housing 17o. The RF coil 17t for the thigh is configured to form a housing by fixing the fixing guide 17g and the RF coil housing 17o together with a detachable part 17v. For this reason, in the RF coil 17t for the thigh, it is preferable that the side of the RF coil housing 17o opposite to the subject P is made of a harder material than the side facing the subject P. The detachable part 17v is a fastener, such as a hook-and-loop fastener, that facilitates the attachment and detachment of the fixing guide 17g and the RF coil housing 17o. In the RF coil 17t for the thigh shown in Figure 4(c), the illustration of the coil cable 17c, coil cable connection mechanism 17cm, fluid pipe 17p, and fluid pipe connection mechanism 17pm of the RF coil 17 is omitted for the sake of simplicity of explanation. With this configuration, even with the RF coil 17t for the thigh, when the bag 17b of the RF coil housing 17o expands due to the fluid flowing in from the fluid inlet / outlet 61, the surface of the bag 17b opposite to the subject P is pressed against the surface of the RF coil housing 17o, thereby increasing the degree of contact between the coil element Ce and the thigh (imaging area) of the subject P (including increasing the holding force of the thigh of the subject P).

[0055] A fixing guide 17g, or a configuration combining the fixing guide 17g and the RF coil housing 17o (RF coil housing 17o-1 and / or RF coil housing 17o-2) (which may include the detachable part 17v), is an example of an "exterior part".

[0056] As described above, in the RF coil device of the embodiment, the coil element Ce is positioned within the RF coil housing 17o on the side that contacts the imaging area of ​​the subject P, and the bag body 17b is positioned on the side of the coil element Ce opposite to the side that contacts the imaging area of ​​the subject P as a holding mechanism. In the RF coil device of the embodiment, the degree of contact between the coil element Ce and the subject P is adjusted (increased or decreased) by allowing fluid (a gas or liquid made of a non-conductive material that is less affected by magnetic fields) to flow in and out of the bag body 17b. As a result, in the medical imaging diagnostic device of the embodiment that employs the RF coil device of the embodiment, the degree of contact between the coil element Ce and the subject P can be adjusted even when the subject P is placed on the top plate 24 and the RF coil device of the embodiment is attached to the subject P. In other words, conventionally, it was not possible to adjust the degree of contact of the RF coil device after the top plate 24 on which the subject P was placed was moved into the bore of the stand device 10, so it was necessary to move the top plate 24 again and pull the subject P out of the bore to make the adjustment. In contrast, in the medical imaging diagnostic apparatus of the embodiment employing the RF coil device of the embodiment, the degree of contact of the RF coil device (more specifically, the coil element Ce) can be adjusted even when the subject P is moved (introduced) into the bore, that is, in an environment where a magnetic field generated by the stand device 10 exists (magnetic field environment). Moreover, in the RF coil device of the embodiment, the holding force of the imaging area of ​​the subject P can be increased by the expansion of the bag body 17b into which the fluid is introduced. As a result, the medical imaging diagnostic apparatus of the embodiment employing the RF coil device of the embodiment can acquire more suitable tomographic images (MR images) of the subject P. Furthermore, the person performing the MRI examination using the medical imaging diagnostic apparatus of the embodiment employing the RF coil device of the embodiment can visually confirm the suitable MR image and perform diagnoses and examinations, such as whether or not there is a lesion in the subject P, more favorably.

[0057] In the above-described embodiment, the configuration of the RF coil 17 in which the coil cable 17c and the fluid pipe 17p are separate, that is, the coil cable connection mechanism 17cm and the fluid pipe connection mechanism 17pm are different connection mechanisms, was described. However, the configuration of the coil cable 17c and the fluid pipe 17p is not limited to the configuration shown in the embodiment. For example, the coil cable 17c and the fluid pipe 17p may be formed as a single unit, that is, the coil cable connection mechanism 17cm and the fluid pipe connection mechanism 17pm may be formed as the same connection mechanism. In this case, the configuration of the RF coil 17 and the function of each component can be easily considered based on the configuration of the RF coil 17 and the function of each component in the above-described embodiment. Therefore, a detailed explanation of the configuration of the RF coil 17 in which the coil cable 17c and the fluid pipe 17p are formed as a single unit, and the function of each component, will be omitted.

[0058] In the embodiment described above, a configuration was described in which there is one fluid path (fluid pipe 17p) for inflowing and outflowing fluid into the bag 17b within the RF coil housing 17o of the RF coil 17. However, the configuration of the fluid pipe 17p for inflowing and outflowing fluid into the bag 17b is not limited to the configuration shown in the embodiment. For example, the fluid path for inflowing and outflowing fluid into the bag 17b may be divided into two: a fluid inflow path for inflowing fluid and a fluid outflow path for outflowing fluid. In this case, the configuration of the RF coil 17 and the functions of each component can be easily considered based on the configuration of the RF coil 17 and the functions of each component in the embodiment described above. Therefore, a detailed explanation of the configuration of the RF coil 17 equipped with a bag 17b with a configuration in which the fluid path for inflowing and outflowing fluid is divided into two, and the functions of each component, will be omitted.

[0059] In the above-described embodiment, the structure of the bag 17b within the RF coil housing 17o of the RF coil 17 was described in which there is only one space for fluid inflow and outflow (a region where fluid is contained). However, the structure of the bag 17b is not limited to the structure shown in the embodiment. For example, the space for fluid inflow and outflow in the bag 17b may be divided into multiple regions (blocks). Here, an example of a structure in which the space for fluid inflow and outflow in the bag 17b is divided into multiple blocks will be described. Figure 5 is a schematic diagram showing an example of another structure of the holding mechanism (bag 17b) provided in the RF coil device (RF coil 17) according to the embodiment. Figure 5(a) shows an example of a cross-section at an arbitrary position of a bag 17b (hereinafter referred to as "bag 17b-a") when the fluid-containing area is divided into multiple blocks by fixing a local (arbitrary) part of a single space with a fixing part 17f, and Figure 5(b) shows an example of a cross-section at an arbitrary position of a bag 17b (hereinafter referred to as "bag 17b-b") when the fluid-containing area is divided into multiple blocks by arranging multiple different bags. In bag 17b-b, each of the arranged bags may be provided with a fluid pipe 17p similar to that of bag 17b in the embodiment described above. This makes it possible to change the amount of fluid flowing in and out of each bag in bag 17b. In other words, in bag 17b-b, the degree of contact between the coil element Ce and the subject P on the imaging site can be changed (including changing the holding force of the subject P) according to the shape of the imaging site. Even with a bag body 17b (bag body 17b-a or bag body 17b-b) of this structure, the configuration of the RF coil 17 and the function of each component can be easily considered based on the configuration of the RF coil 17 and the function of each component in the above-described embodiment. Therefore, a detailed explanation of the configuration of the RF coil 17 and the function of each component in a bag body 17b having a structure in which the area containing the fluid is divided into multiple blocks will be omitted.

[0060] According to at least one embodiment described above, an RF coil device (17) that receives electromagnetic waves emitted from a subject (P) in response to an RF pulse irradiated onto the subject (P) under the influence of a magnetic field, comprises a plurality of RF coil elements (Ce) arranged in a planar manner, a holding mechanism (17b) through which a non-conductive fluid flows in or out from a fluid path (17p), and an outer casing (17o) housing the plurality of RF coil elements and the holding mechanism, wherein each of the RF coil elements is positioned on the inner surface of the outer casing on the side of the outer casing that contacts the subject, and the holding mechanism is positioned on the inner surface of the outer casing on the side opposite to the side of the outer casing that contacts the subject, thereby enabling adjustment of the position of the subject while it is moved inside the mounting device in an RF coil device that can be attached to a subject used in an environment with a magnetic field.

[0061] While several embodiments have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0062] 1··MRI device, 10··Stand device, 12··Static magnetic field magnet, 14··Gradient magnetic field coil, 16··RF coil, 17,17h,17e,17w,17t··RF coil, 17a··Hole, 17b,17b-a,17b-b··Bag, 17c··Coil cable, 17cm··Coil cable connection mechanism, 17f··Fixing part, 17g··Fixing guide, 17gb··Fixing guide band, 17o··RF coil housing, 17p··Fluid pipe, 17pm··Fluid pipe connection mechanism, 17v··Detachable part, 20··Table device, 22··Base, 24· ··Top plate, 24f··Subject fixing section, 24v··Detachable section, 26··Coil port, 30··Control device, 31··Sequence control circuit, 32··Gradient field power supply, 33··Transmitting circuit, 34··Receiver circuit, 35··Bed control circuit, 40··Console device, 41··Memory, 42··Display, 43··Input interface, 50··Processing circuit, 51··Acquisition function, 52··Reconstruction processing function, 53··Image processing function, 54··Output control function, 55··Fluid control function, 60··Mechanical device, 61··Fluid inlet / outlet, Ce··Coil element

Claims

1. An RF coil device that receives electromagnetic waves emitted from a subject in response to an RF pulse irradiated onto the subject under the influence of a magnetic field, Multiple RF coil elements arranged in a planar manner, A holding mechanism through which a non-conductive fluid flows in or out of a fluid path, An outer casing housing the plurality of RF coil elements and the holding mechanism, Equipped with, Each of the RF coil elements is arranged on the inner surface of the outer casing on the side of the outer casing that contacts the subject, The holding mechanism is positioned on the inner surface of the outer casing opposite to the side of the outer casing that contacts the object to be examined. RF coil device.

2. The aforementioned holding mechanism is The fluid expands upon inflow, increasing the degree of contact between the subject and the plurality of RF coil elements. The fluid is released, causing it to contract and reducing the degree of adhesion. The outer casing, when the holding mechanism expands, presses down on the side of the holding mechanism opposite to the side that contacts the object being held. The RF coil device according to claim 1.

3. The fluid path is formed separately from the signal output cable that outputs the nuclear magnetic resonance signal based on the electromagnetic wave received by each of the RF coil elements to the outside. The RF coil device according to claim 2.

4. The fluid path is formed integrally with a signal output cable that outputs a nuclear magnetic resonance signal based on the electromagnetic waves received by each of the RF coil elements to the outside. The RF coil device according to claim 2.

5. The fluid path is formed integrally with a fluid inflow path for introducing the fluid into the holding mechanism and a fluid outflow path for introducing the fluid from the holding mechanism. The RF coil device according to claim 2.

6. The fluid path is formed by separating a fluid inflow path for introducing the fluid into the holding mechanism and a fluid outflow path for introducing the fluid from the holding mechanism. The RF coil device according to claim 2.

7. The holding mechanism is configured such that the space through which the fluid flows in or out is divided into multiple sections. The RF coil device according to any one of claims 2 to 6.

8. An RF coil device for receiving electromagnetic waves emitted from a subject in response to an RF pulse irradiated onto the subject under the influence of a magnetic field, comprising: a plurality of RF coil elements arranged in a planar manner; a holding mechanism through which a non-conductive fluid flows in or out from a fluid path; and an outer casing housing the plurality of RF coil elements and the holding mechanism, wherein each of the RF coil elements is positioned on the inner surface of the outer casing on the side of the outer casing that contacts the subject, and the holding mechanism is positioned on the inner surface of the outer casing opposite to the side of the outer casing that contacts the subject, and a medical imaging diagnostic device for capturing a medical image of the subject using such an RF coil device, A control unit that allows the fluid to flow into or out of the holding mechanism, A medical imaging diagnostic device equipped with [a specific feature].

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