JP2014061264A - Magnetic resonance imaging apparatus, bed device, and rf coil device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To favorably and wirelessly send digitized nuclear magnetic-resonance signals to an MRI apparatus from an RF coil device.SOLUTION: MRI apparatuses (20A, 20B) are provided with: first wireless communication parts (200A-200E); a second wireless communication part (300); an image reconstruction part (56); and a top plate (34). The first wireless communication parts acquire nuclear magnetic-resonance signals detected by an RF coil device (100) and wirelessly send digitized nuclear magnetic resonance signals by means of induction electric field. The second wireless communication part receives the nuclear magnetic resonance signals wirelessly sent from the first wireless communication parts via the induction electric field. The image reconstruction part reconstructs image data on a subject on the basis of the nuclear magnetic resonance signals received by the second wireless communication part. The top plate is provided with support parts (500A-500E) detachably supporting the first wireless communication parts to the second wireless communication part.

Description

  Embodiments described herein relate generally to a magnetic resonance imaging apparatus, a bed apparatus, and an RF coil apparatus.

  MRI is an imaging method in which a nuclear spin of a subject placed in a static magnetic field is magnetically excited with an RF pulse having a Larmor frequency, and an image is reconstructed from MR signals generated by the excitation. The MRI means magnetic resonance imaging, the RF pulse means radio frequency pulse, and the MR signal means nuclear magnetic resonance signal. .

  Here, for example, an RF coil device (Radio Frequency Coil Device) detects an generated MR signal by transmitting an RF pulse to a nuclear spin in a subject by passing an RF pulse current through the coil. Some RF coil apparatuses are built in the MRI apparatus itself, but some are recognized by the control unit of the MRI apparatus by connector connection with a connection port of the MRI apparatus, for example, a local RF coil apparatus. .

  In MRI, the acquisition system of MR signals is becoming multichannel. The channel here means each path of a plurality of MR signals that are output from each coil element in the RF coil apparatus and input to the RF receiver of the MRI apparatus. The number of channels is set to be equal to or less than the number of inputs received by the RF receiver, but many RF coil devices can be connected to the MRI apparatus.

  If the number of connection cables between the RF coil apparatus and the MRI apparatus increases due to the increase in the number of channels, the wiring becomes complicated, which is inconvenient. For this reason, it is desired to wirelessly transmit and receive signals between the RF coil device and the MRI apparatus, but wireless transmission using analog signals has not been realized. This is because there are various restrictions such as a decrease in dynamic range.

  More specifically, in the MRI apparatus, in order to suppress the influence on the reception sensitivity with respect to the weak MR signal radiated from the subject, the output of the electromagnetic wave used for wireless communication between the RF coil apparatus and the MRI apparatus is increased. I can't. When the radio output cannot be increased, the dynamic range is reduced due to signal loss when the transmission signal propagates in space. Therefore, Patent Document 1 proposes a digital wireless transmission method in which MR signals are digitized and then wirelessly transmitted.

JP 2010-29644 A

  If the MR signal is digitized and then transmitted wirelessly, the problem of dynamic range restriction can be solved, but there are the following problems. First, restrictions on radio are different for each country, and the same transmission frequency or the same transmission power is not always available in every country. Second, when an MR signal is wirelessly transmitted from the RF coil apparatus to the MRI apparatus, the transmission radio wave may be reflected around and deteriorate the transmission data of its own wireless communication.

  For this reason, in MRI, there has been a demand for a new technique for satisfactorily wirelessly transmitting a digitized MR signal from the RF coil apparatus to the MRI apparatus.

Hereinafter, several examples of the modes that the embodiments of the present invention can take will be described for each mode.
(1) An MRI apparatus according to an embodiment acquires an MR signal from an RF coil apparatus that detects an MR signal emitted from a subject, and includes a first wireless communication unit, a second wireless communication unit, An image reconstruction unit and a top plate are provided.
The first wireless communication unit acquires the MR signal detected by the RF coil device, and wirelessly transmits the digitized MR signal via the induction electric field.
The second wireless communication unit receives the MR signal wirelessly transmitted from the first wireless communication unit via the induced electric field.
The image reconstruction unit reconstructs the image data of the subject based on the MR signal received by the second wireless communication unit.
The first wireless communication unit is detachably supported with respect to the second wireless communication unit so that the interval between the first wireless communication unit and the second wireless communication unit is an interval that enables wireless transmission via an induction electric field. A supporting portion is provided on the top plate. A subject is placed on the top board.

(2) A couch device according to an embodiment includes a top plate on which a subject is placed, and receives MR signals detected by an RF coil device when magnetic resonance imaging is performed. In this bed apparatus, the top plate includes a signal acquisition unit and a support unit.
The signal acquisition unit receives the digitized MR signal wirelessly transmitted from the wireless communication unit of the RF coil device via the induction electric field via the induction electric field.
The support unit detachably supports the wireless communication unit with respect to the signal acquisition unit so that the interval between the wireless communication unit and the signal acquisition unit is an interval at which wireless transmission via an induction electric field is possible.

(3) An RF coil device according to an embodiment of the present invention includes a detection unit, an A / D conversion unit, and a wireless communication unit.
The detection unit detects an MR signal emitted from the subject.
The A / D conversion unit digitizes the MR signal.
The wireless communication unit is supported detachably with respect to the support unit of the MRI apparatus, and when supported by the support unit, the digitized MR signal is wirelessly transmitted to the MRI apparatus via an induced electric field. Send.

1 is a block diagram showing the overall configuration of an MRI apparatus in a first embodiment. The schematic diagram which shows an example of the structure of RF coil apparatus in 1st Embodiment, an example of arrangement | positioning of a control side radio | wireless communication apparatus, and the fixing method of a coil side radio | wireless communication apparatus. FIG. 3 is a schematic perspective view showing an overview of a state in which the coil side wireless communication device and the fixing mechanism are separated from each other in the first embodiment. FIG. 3 is a schematic perspective view showing an overview of a state in which the coil-side wireless communication device is fixed by a fixing mechanism in the first embodiment. In 1st Embodiment, the cross-sectional schematic diagram of the state by which the coil side radio | wireless communication apparatus was fixed by the fixing mechanism. The block diagram which shows typically the function of each part in connection with transmission of MR signal detected with the coil element of RF coil apparatus in 1st Embodiment. 6 is a flowchart illustrating an example of a flow of an imaging operation by the MRI apparatus according to the first embodiment. The typical perspective view which shows the fixing mechanism which fixes a coil side radio | wireless communication apparatus in the MRI apparatus of 2nd Embodiment. In 2nd Embodiment, the cross-sectional schematic diagram of the state which fitted each protrusion of the coil side radio | wireless communication apparatus to each fixing | fixed part of a top plate. The cross-sectional schematic diagram of the fixing mechanism in the state by which the coil side radio | wireless communication apparatus is not fixed in the MRI apparatus of 3rd Embodiment. The cross-sectional schematic diagram of the fixing mechanism in the state by which the coil side radio | wireless communication apparatus was fixed in the MRI apparatus of 3rd Embodiment. The block diagram which shows the function of each part in connection with transmission of MR signal detected with the coil element in the MRI apparatus of 4th Embodiment similarly to FIG. The typical perspective view of the fixing mechanism in the state where the coil side radio | wireless communication apparatus is not fixed in the MRI apparatus of 4th Embodiment. The cross-sectional schematic diagram of the fixing mechanism in the state by which the coil side radio | wireless communication apparatus was fixed in the MRI apparatus of 4th Embodiment. The cross-sectional schematic diagram of the fixing mechanism which concerns on the modification of 4th Embodiment. The cross-sectional schematic diagram of the fixing mechanism in the MRI apparatus of 5th Embodiment. In 5th Embodiment, the upper surface schematic diagram of a part of top plate in the state where the coil side radio | wireless communication apparatus is not fixed. FIG. 18 is a schematic top view showing a state where the coil-side wireless communication device is placed on the top plate so as to close four suction ports from the state of FIG. 17. In 5th Embodiment, the schematic diagram explaining the timing of the automatic stop of suction operation | movement with the flow of the slide movement of a top plate. As a modification of the fifth embodiment, a schematic cross-sectional view showing a state where the coil-side wireless communication device is placed on the top so as to match the guide frame when there is one suction port. The upper surface schematic diagram of the top plate of the state of FIG. The block diagram which shows the whole structure of the MRI apparatus in 6th Embodiment. The block diagram which shows typically the function of each part in connection with transmission of MR signal detected with the coil element of RF coil apparatus in 6th Embodiment.

  In the following embodiments, a first wireless communication unit and a second wireless communication unit capable of wireless communication via an induced electric field are respectively disposed on the RF coil device side and the control side of the MRI device. In this case, for example, the first wireless communication unit is fixed to the second wireless communication unit so as to be detachable within a close distance, and the digitized MR signal is transmitted from the first wireless communication unit to the second wireless communication via the induced electric field. Wirelessly transmitted to the unit. With the novel technique as described above, it is possible to achieve the above-described problem (objective) of satisfactorily wirelessly transmitting a digitized MR signal from the RF coil apparatus to the MRI apparatus.

  Here, since the MR signal transmission period becomes longer as the imaging time becomes longer, the RF coil device attached to the subject P may move due to the movement of the subject P during imaging. In that case, in the above configuration, it is desirable to eliminate the fear that the MR signal detected from the subject P cannot be wirelessly transmitted by a more reliable fixing method due to the movement of the RF coil device. .

  Therefore, in the following embodiment, it is a further problem to fix the first wireless communication unit to the second wireless communication unit with a more reliable method, and to prevent communication inhibition due to, for example, human error as described above. . The MRI apparatus of (1), the bed apparatus of (2), and the RF coil apparatus of (3) are each configured to achieve the further problem.

  Hereinafter, several examples of embodiments of an MRI apparatus, a bed apparatus, an RF coil apparatus, and an MRI method will be described with reference to the accompanying drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same element and the overlapping description is abbreviate | omitted.

<First Embodiment>
FIG. 1 is a block diagram showing the overall configuration of the MRI apparatus 20A in the first embodiment. As shown in FIG. 1, the MRI apparatus 20 </ b> A includes a gantry 21, a bed apparatus 30, and a control apparatus 40.
The MRI apparatus 20A includes, for example, a static magnetic field magnet 22, a shim coil 24, a gradient magnetic field coil 26, and a transmission RF coil 28 in a gantry 21 formed in a cylindrical shape. The gantry 21 corresponds to a portion indicated by a thick line in the drawing.

The couch device 30 includes a support table 31, a top plate drive device 32 disposed in the support table 31, and a top plate 34. Here, as an example, the bed apparatus 30 is a movable dockable type and includes a connection unit (not shown). The couch device 30 is connected to the gantry 21 via the connection portion, and receives a control signal from the control device 40 via the connection portion. The support base 31 supports the top plate 34 so as to be movable in the horizontal direction (Z-axis direction of the apparatus coordinate system). Further, since the support table 31 has, for example, four casters 35 on the bottom surface, the bed apparatus 30 can move the patient onto the top plate 34 in another room, move to the imaging room, and can be docked to the gantry 21 in the imaging room. Configured. In order to be movable, the number of casters 35 is desirably three or more.
The bed apparatus 30 is not limited to the dockable type, and may be a type in which the position of the support base 31 is fixed in the imaging chamber.

  A subject P is placed on the top plate 34. The static magnetic field magnet 22 and the shim coil 24 are, for example, cylindrical, and the shim coil 24 is arranged on the inner side of the static magnetic field magnet 22 with the same axis as the static magnetic field magnet 22.

  Here, as an example, the X-axis, Y-axis, and Z-axis that are orthogonal to each other in the apparatus coordinate system are defined as follows. First, the static magnetic field magnet 22 and the shim coil 24 are arranged so that their axial directions are orthogonal to the vertical direction, and the axial direction of the static magnetic field magnet 22 and the shim coil 24 is the Z-axis direction. Further, it is assumed that the vertical direction is the Y-axis direction, and the top plate 34 is arranged such that the normal direction of the mounting surface is the Y-axis direction. In the following description, it is assumed that the X axis, the Y axis, and the Z axis are in the apparatus coordinate system unless otherwise specified.

  The control device 40 of the MRI apparatus 20A includes a static magnetic field power supply 41, a shim coil power supply 42, a gradient magnetic field power supply 44, an RF transmitter 46, an RF receiver 48, a system control unit 52, a system bus 54, an image The reconstruction unit 56, the image database 58, the image processing unit 60, the input device 62, the display device 64, and the storage device 66 are included.

  The static magnetic field magnet 22 forms a static magnetic field in the imaging space by the current supplied from the static magnetic field power supply 41. The imaging space means, for example, a space in the gantry 21 where the subject P is placed and a static magnetic field is applied.

  The static magnetic field magnet 22 is often composed of a superconducting coil, and is connected to the static magnetic field power source 41 and supplied with current during excitation, but after being excited, it is disconnected. It is common. In addition, you may comprise the static magnetic field magnet 22 with a permanent magnet, without providing the static magnetic field power supply 41. FIG.

  The shim coil 24 is connected to the shim coil power source 42 and equalizes the static magnetic field by the current supplied from the shim coil power source 42.

  For example, the gradient magnetic field coil 26 is formed in a cylindrical shape inside the static magnetic field magnet 22. The gradient coil 26 forms a gradient magnetic field Gx in the X-axis direction, a gradient magnetic field Gy in the Y-axis direction, and a gradient magnetic field Gz in the Z-axis direction in the imaging region by current supplied from the gradient magnetic field power supply 44. That is, the gradient magnetic fields Gx, Gy, and Gz in the three-axis direction of the apparatus coordinate system are synthesized, and the slice selection direction gradient magnetic field Gss, the phase encode direction gradient magnetic field Gpe, and the readout direction (frequency encode direction) gradient magnetic field as logical axes. Each direction of Gro can be set arbitrarily.

  Note that the imaging region refers to a region set as a part of the imaging space, for example, an MR signal collection range used to generate one image or one set of images. “One set of images” refers to “multiple images” when MR signals of a plurality of images are collected in one pulse sequence, such as multi-slice imaging. The imaging area is defined three-dimensionally in the apparatus coordinate system, for example.

  The RF transmitter 46 generates an RF pulse (RF current pulse) with a Larmor frequency for causing nuclear magnetic resonance based on the control information input from the system control unit 52 and transmits this to the RF coil 28 for transmission. To do. The transmission RF coil 28 receives an RF pulse from the RF transmitter 46 and transmits the RF pulse to the subject P. The transmission RF coil 28 includes a whole body coil (not shown) that is built in the gantry 21 and also transmits and receives RF pulses.

  A receiving RF coil 29 is disposed inside the top plate 34. The reception RF coil 29 detects an MR signal generated when the nuclear spin in the subject P is excited by an RF pulse, and transmits the detected MR signal to the RF receiver 48.

  The RF coil device 100 is, for example, a wearable local coil for receiving MR signals. Here, the RF coil device 100 is shown as being mounted on the chest of the subject P and receiving MR signals from the chest, but this is only an example. In the MRI apparatus 20A, in addition to the RF coil apparatus 100, various wearing type RF coil apparatuses such as a shoulder RF coil apparatus and a waist RF coil apparatus can be used for receiving MR signals.

  These receiving RF coil devices (100) are part of the MRI apparatus 20A as an example here, but may be regarded as separate from the MRI apparatus 20A. The RF coil device 100 includes a cable 102 and a coil-side wireless communication device 200A connected to the tip of the cable 102.

  A plurality of control-side wireless communication devices 300 are arranged inside the top plate 34. The above-described digitized MR signal wireless communication is performed between one coil-side wireless communication device 200A and any one control-side wireless communication device 300.

  However, this is not the case, for example, when a plurality of RF coil devices are attached to the subject P. In this case, digitalization was performed between the plurality of coil-side wireless communication devices 200A corresponding to the plurality of RF coil devices and the plurality of control-side wireless communication devices 300 respectively corresponding to the plurality of coil-side wireless communication devices 200A. Wireless communication of MR signals is performed. The wireless communication operation will be described later.

  In FIG. 1, only two control-side wireless communication devices 300 are illustrated because of complexity, but the number of control-side wireless communication devices 300 may be three or more, or only one. However, it is more preferable that a large number of control-side wireless communication devices 300 are arranged in a discrete manner than in the case of a single arrangement. This is because there is more room for selection when the coil-side radio communication device 200 </ b> A is fixed in proximity to the control-side radio communication device 300.

  In other words, it is because the coil-side radio communication device 200 </ b> A can be fixed in proximity to the control-side radio communication device 300 closest to the RF coil device 100 when there is more room for selection of fixed locations. By doing so, the cable 102 connecting the RF coil device 100 and the coil-side wireless communication device 200A can be shortened. The above-mentioned “proximity fixation” means, for example, fixing so as not to move physically within a range (closeness) electromagnetically coupled to each other to such an extent that wireless communication via an induction electric field is possible. It is.

  In this embodiment, as an example, transmission of an RF pulse to the transmission RF coil 28 in the MRI apparatus 20A and transmission of an MR signal detected from the subject P are performed by the coil-side radio communication apparatus 200A-control-side radio communication. This is performed by wire except between the devices 300.

  The RF receiver 48 performs predetermined signal processing on the detected MR signal to generate digitized MR signal complex data (hereinafter referred to as MR signal raw data). The RF receiver 48 inputs the generated raw data of the MR signal to the image reconstruction unit 56.

  The system control unit 52 performs system control of the entire MRI apparatus 20A via wiring such as the system bus 54 in the imaging operation and image display after imaging.

  Therefore, the system control unit 52 stores control information necessary for driving the gradient magnetic field power supply 44, the RF transmitter 46, and the RF receiver 48. The control information here is, for example, sequence information describing operation control information such as the intensity, application time, and application timing of the pulse current applied to the gradient magnetic field power supply 44.

  The system control unit 52 drives the gradient magnetic field power supply 44, the RF transmitter 46, and the RF receiver 48 according to the stored predetermined sequence to generate gradient magnetic fields Gx, Gy, Gz, and RF pulses.

  In addition, the system control unit 52 controls the top plate driving device 32 to move the top plate 34 in the Z-axis direction so that the top plate 34 is taken in and out of the imaging space inside the gantry 21. Further, the system control unit 52 can raise and lower the top plate 34 in the Y-axis direction by controlling the top plate driving device 32 and changing the height of the support base 31. The system control unit 52 controls the position of the top plate 34 in this way, thereby positioning the imaging region of the subject P on the top plate 34 at the magnetic field center in the imaging space.

The system control unit 52 also functions as an imaging condition setting unit. That is, the system control unit 52 sets the imaging conditions for the main scan based on the information about the subject P input by the operator to the input device 62 and some imaging conditions. For this purpose, the system control unit 52 causes the display device 64 to display imaging condition setting screen information.
The input device 62 provides the operator with a function for setting imaging conditions and image processing conditions.

  The imaging condition means, for example, what kind of pulse sequence is used, what kind of condition is used to transmit an RF pulse or the like, and under what kind of condition the MR signal is collected from the subject P. Examples of imaging conditions include an imaging area as positional information in the imaging space, an imaging site, the type of pulse sequence such as parallel imaging, the type of RF coil device to be used, the number of slices, the interval between slices, etc. It is done.

  The imaging part means, for example, which part of the subject P such as the head, chest, and abdomen is imaged as an imaging region.

  The “main scan” is a scan for capturing a target diagnostic image such as a proton density weighted image, and does not include a scan for acquiring MR signals for positioning images and a scan for calibration. A scan refers to an MR signal acquisition operation and does not include image reconstruction. For example, the calibration scan refers to a scan that is performed separately from the main scan in order to determine uncertain imaging conditions of the main scan or conditions and data used for image reconstruction after the main scan. . The pre-scan described later refers to a calibration scan that is performed before the main scan.

  The image reconstruction unit 56 converts the raw data of the MR signal input from the RF receiver 48 into, for example, matrix data based on the number of phase encoding steps and the number of frequency encoding steps, and stores this as k-space data. The k space means a frequency space (Fourier space). The image reconstruction unit 56 generates image data of the subject P by performing image reconstruction processing including two-dimensional Fourier transform on the k-space data. The image reconstruction unit 56 stores the generated image data in the image database 58.

  The image processing unit 60 takes image data from the image database 58, performs predetermined image processing on the image data, and stores the image data after the image processing in the storage device 66 as display image data.

The storage device 66 stores the above-described display image data, with the imaging conditions used to generate the display image data, information on the subject P (patient information), and the like attached thereto as incidental information.
Under the control of the system control unit 52, the display device 64 displays a screen for setting imaging conditions for the main scan, an image indicated by image data generated by imaging, and the like.
In the above description, the components of the MRI apparatus 20A are classified into the gantry 21, the bed apparatus 30, and the control apparatus 40. However, this is only an example of interpretation. For example, the top plate moving mechanism 32 may be regarded as a part of the control device 40.

  FIG. 2 is a schematic diagram illustrating the configuration of the RF coil device 100, an example of the arrangement of the control-side wireless communication device 300, and an example of a fixing method of the coil-side wireless communication device 200A.

  As shown in FIG. 2, the RF coil device 100 includes a cable 102, a cover member 104, and the above-described coil-side wireless communication device 200A. The cover member 104 is formed such that it can be bent and deformed by a flexible material. As the deformable material, for example, a flexible printed circuit (FPC) described in JP 2007-229004 A can be used.

  In the cover member 104, a plurality of coil elements (surface coils) 106 that function as antennas for detecting MR signals from the subject P are arranged. Here, as an example, six coil elements 106 are illustrated, but the number and shape of the coil elements 106 are not limited to those illustrated.

  A control circuit 108 that controls the operation of the RF coil device 100 is provided in the cover member 104. Although there are other components such as an A / D converter 212 (analog to digital converter) in the cover member 104, details thereof will be described later with reference to FIG.

  Here, as an example, the coil side wireless communication device 200A is a part of the RF coil device 100, but this is only an example of interpretation. The RF coil device 100 and the coil-side wireless communication device 200A may be configured as separate components.

  One end of the cable 102 is connected to the coil-side radio communication device 200 </ b> A of the MRI apparatus 20 </ b> A, and the other end is connected to the control circuit 108 in the cover member 104.

  Further, in the cover member 104 of the RF coil device 100, a preamplifier PMP (see FIG. 6 described later) for amplifying the MR signal detected by the coil element 106, a band-pass filter for filtering, and the like are provided. Also good.

  Here, as an example, eight control-side wireless communication apparatuses 300 are embedded immediately below the surface of the top plate 34 on which the subject P is placed (hereinafter referred to as the top surface of the top plate 34). For example, the subject P is placed in the center in the width direction of the top plate 34 (X-axis direction in FIG. 1). Therefore, in this example, the control-side wireless communication devices 300 are arranged in a discrete manner in rows along the longitudinal direction (Z-axis direction) of the top plate 34 on both ends in the width direction of the top plate 34. ing.

  The number and arrangement location of the control-side wireless communication devices 300 are not limited to the mode of FIG. 2 (inside the top plate 34). For example, the control-side wireless communication device 300 may be disposed so as to be exposed on the top board 34 or the gantry 21, disposed inside the gantry 21, or disposed on the support base 31. . However, in each of the following embodiments, as an example, a fixing mechanism 500A to 500E for fixing the coil side wireless communication devices (200A to 200E) will be described. It is assumed that it is arranged in the top plate 34.

  In the first embodiment, the top plate 34 has eight fixing mechanisms 500A fixed on the upper surface thereof. The eight fixing mechanisms 500A (each support member 502a: see FIG. 3) are fixed at positions facing the eight control-side wireless communication devices 300 in the thickness direction of the top plate 34, respectively. About a fixing method, what is necessary is just to form integrally with adhesion or the material of the upper surface of the top plate 34, for example.

  FIG. 3 is a schematic perspective view showing an overview of a state where the coil side wireless communication device 200A and the fixing mechanism 500A are separated from each other. As shown in FIG. 3, the fixing mechanism 500A includes a support member 502a and an elastic member 510 that covers an insertion port 506 formed in the support member 502a.

  The coil side wireless communication device 200A includes a housing 202a and a columnar protrusion 240a. Here, as an example, the protrusion 240a is arranged at the center of the surface of the housing 202a opposite to the surface to which the cable 102 is connected. This is because the coil side wireless communication device 200 </ b> A is slid on the top surface of the top plate 34 so that the protrusion 240 a can be easily fitted into the insertion port 506.

  The support member 502a of the fixing mechanism 500A has a contour obtained by bending a flat plate formed of a non-magnetic material that does not deform, and has a L-shaped cross section. Note that, by forming the fixing mechanism 500A using a non-magnetic material, it is possible to avoid an influence on wireless communication via an induction electric field. The insertion port 506 is formed on a surface of the support member 502a parallel to the thickness direction of the top plate 34. The insertion opening 506 has a circular opening, and its diameter and depth are dimensions for fitting the protrusion 240a. The periphery of the insertion port 506 is formed of an elastic member 510 having elasticity such as rubber. Here, the elastic member 510 has a cylindrical shape as an example, and can be formed of, for example, silicone rubber, polyethylene, synthetic resin, or the like.

  FIG. 4 is a schematic perspective view showing an overview of a state where the coil-side wireless communication device 200A is fixed by the fixing mechanism 500A. The coil-side wireless communication device 200A can be fitted to the fixing mechanism 500A by sliding the coil-side wireless communication device 200A from the state of being placed on the top surface of the top plate 34. That is, as shown in FIG. 4, both are coupled so that the projection 240 a is fitted into the insertion opening 506, and the coil-side wireless communication device 200 </ b> A is securely fixed on the top plate 34 by the frictional force of the elastic member 510. Is done.

  FIG. 5 is a schematic cross-sectional view of the coil-side radio communication device 200A fixed by the fixing mechanism 500A. As illustrated in FIG. 5, the coil side wireless communication device 200 </ b> A includes antennas 206 a, 206 b, 206 c, and 206 d in the housing 202. The antennas 206a to 206d are arranged on the bottom surface side that is the top plate 34 side when fixed by the fixing mechanism 500A in the housing 202a. A control circuit (not shown) in the housing 202 a is connected to the control circuit 108 in the cover member 104 of the RF coil device 100 and the like via the cable 102.

  The control-side wireless communication apparatus 300 includes a housing 302 and antennas 306a, 306b, 306c, and 306d. There are other components such as a reference signal transmission unit in the housing 302, and details thereof will be described later with reference to FIG. The antennas 306 a to 306 d are arranged on the upper surface side (the upper surface side of the top plate 34) in the housing 302.

  The antennas 306a to 306d are paired with the antennas 206a to 206d (four pairs in total). Among these, at least the antennas 206a to 306a are, for example, inductive electric field coupling couplers described later.

  In this example, the control-side wireless communication device 300 is fixedly disposed in the top board 34 and therefore does not move. Since the fixing mechanism 500A is also fixed to the upper surface of the top plate 34, it does not move. Therefore, the coil-side radio communication device 200A is detachably fixed at a position facing the control-side radio communication device 300 by the fixing mechanism 500A provided on the top plate 34.

  The antennas 206a to 206d are arranged at positions facing the antennas 306a to 306d, respectively, when the coil side wireless communication device 200A is fixed to the control side wireless communication device 300 by the fixing mechanism 500A.

  Here, the control-side wireless communication devices 300 are discretely arranged at a plurality of locations on the top plate 34. Therefore, no matter what part of the subject P the RF coil device is attached to, the coil-side radio communication device 200A may be fixed in proximity to the nearest control-side radio communication device 300. Although the first embodiment is an example of the RF coil device 100 for the chest, this point can also be said in the case of a combination of the RF coil device for another region and the coil-side radio communication device 200A. For this reason, the length of the cable 102 can be shortened.

  Proximity wireless communication via an induction electric field is executed between the coil-side wireless communication device 200A and the control-side wireless communication device 300. An induced electric field is an electric field generated by a change in magnetic flux density over time. As the close proximity wireless communication via the induction electric field, for example, a transfer jet (TransferJet: registered trademark) using an induction electric field coupling type coupler as an antenna may be used (see, for example, Japanese Patent Application Laid-Open No. 2010-147922).

  More specifically, the induction electric field coupling type coupler has a coupling electrode, a resonant stub, a ground, and the like (not shown). When an electrical signal is input to the resonant stub on the transmission side of the inductive field coupled coupler, charges are accumulated in the coupling electrode, and virtual charges equivalent to the charges are generated on the ground. These electric charges form a minute electric dipole, and this minute electric dipole functions as a transmitting antenna. That is, data is transferred to the receiving side by a longitudinal wave induced electric field generated by a minute electric dipole. Longitudinal waves that oscillate parallel to the traveling direction do not depend on the direction of the antenna, so that stable data transfer can be realized.

  However, if the transmitting side and the receiving side are separated too much, the two cannot be electromagnetically coupled, and data transmission cannot be performed. This is because the induction electric field formed by the induction electric field coupling type coupler is abruptly attenuated when separated.

In FIG. 5, in order to distinguish each component, the antennas 206a to 206d are arranged apart from each other and the antennas 306a to 306d are arranged apart from each other. Interference between wireless communication paths can be avoided.
Specifically, the radio frequency may be separated between the antennas 206a and 306a, between the antennas 206b and 306b, between the antennas 206c and 306c, and between the antennas 206d and 306d (the frequency value may be greatly separated). At this time, in each wireless communication path, it is desirable to avoid a frequency that is an integral fraction of the center frequency of the RF pulse transmitted to the subject P.

  It is desirable that the installation location of the control-side wireless communication device 300 is not too deep from the top surface of the top plate 34. If the positions of the antennas 306a to 306d of the control-side wireless communication apparatus 300 are too deep, the distance D between the antennas 206a to 206d and 306a to 306d on the transmission side and the reception side is electromagnetically coupled to each other (FIG. 5). Cannot be brought close together. In that case, wireless communication via an induced electric field becomes difficult. That is, it is desirable that the control-side wireless communication device 300 is disposed at a position where the control-side wireless communication device 300 can be fixed in proximity to the coil-side wireless communication device 200A to the extent that it is electromagnetically coupled.

  As long as the electric dipole itself (antenna) on the coil-side radio communication apparatus 200A side and the electric dipole itself (antenna) on the control-side radio communication apparatus 300 side are not in direct contact, the antenna on the coil-side radio communication apparatus 200A side is used. And a housing that covers the antenna on the control-side wireless communication apparatus 300 side may be brought into contact with each other. This is because it is only necessary to secure a gap D in which an induced electric field is generated between the transmitting antenna and the receiving antenna. Therefore, the control-side wireless communication device 300 may be exposed so that the antenna-side surface is aligned with the top surface of the top plate 34.

  FIG. 6 is a block diagram schematically showing the function of each part related to the transmission of the MR signal detected by the coil element 106 of the RF coil device 100. As shown in FIG. 6, in the cover member 104 (of the RF coil device 100), the control circuit 108, the plurality of coil elements 106, and a plurality of preamplifiers respectively corresponding to the plurality of coil elements 106 are provided. A PMP and a plurality of A / D converters 212, a P / S converter (Parallel / Serial Converter) 214, and a rechargeable battery BA are arranged.

  In addition to the antennas 206a to 206d described above, the coil-side wireless communication device 200A includes a data transmission unit 216, a reference signal reception unit 218, an ID transmission unit (Identification Information Transmitting Unit) 222, a gate signal reception unit 224, It further has a coil L2.

In FIG. 6, the wiring between the gate signal receiving unit 224 and the control circuit 108, the wiring between the coil L2 and the rechargeable battery BA, the wiring between the reference signal receiving unit 218 and each A / D converter 212, and the P / S conversion. The wiring between the device 214 and the data transmission unit 216 is accommodated in the cable 102 (see FIG. 2). In FIG. 6, the cable 102 is not shown because it is complicated.
The coil L2 in the coil-side wireless communication device 200A and the rechargeable battery BA in the cover member 104 constitute the power receiving unit 220.

  In addition to the antennas 306a to 306d, the control-side wireless communication apparatus 300 includes a data reception unit 316, a reference signal transmission unit 318, a power supply unit 320, an ID reception unit (Identification Information Receiving Unit) 322, a gate And a signal transmission unit 324. The power supply unit 320 includes a coil L1.

  The control device 40 of the MRI apparatus 20A further includes a frequency up-conversion unit 402, a pulse waveform generation unit 404, a fixed frequency generation unit 406, and a variable frequency generation unit 408 in addition to the components shown in FIG. Further, the RF receiver 48 includes a frequency down-conversion unit 410 and a signal processing unit 412.

  In the first embodiment, as an example, a region where a charging induction magnetic field is generated and four wireless communication paths exist between the coil-side wireless communication device 200A and the control-side wireless communication device 300. Hereinafter, these will be described in order.

  When the coil L2 is in a range close enough to be electromagnetically coupled to the coil L1, that is, when the coil-side wireless communication device 200A is fixed in proximity to the control-side wireless communication device 300 by the fixing mechanism 500A. think of. In this case, an electromotive force is generated in the coil L2 by an induced magnetic field generated when the power supply unit 320 causes the primary current to flow through the coil L1. Due to this electromotive force, a secondary current flows through the coil L2, and the rechargeable battery BA is charged.

  The power receiving unit 220 supplies the power charged as described above to each unit in the coil-side wireless communication device 200A and each unit in the cover member 104 via a wiring (not shown). Here, it is desirable to separate the frequency of the primary current flowing through the coil L1 from the communication frequencies of the four wireless communication paths. This is to avoid interference between signals on the four wireless communication paths between the antennas 206a to 206d and 306a to 306d and the primary side current and the secondary side current.

  As a method of securing the power of the RF coil device 100, the rechargeable battery BA may be charged during the unused period of the RF coil device 100, instead of the power receiving unit 220 and the power supply unit 320. Alternatively, another rechargeable battery that is charged during an unused period of the RF coil device 100 and the power supply by the power receiving unit 220 and the power supply unit 320 may be used in combination.

  Next, the four wireless communication paths will be described. The wireless communication via the induction electric field is performed at least between the antennas 206a and 306a, but may be performed between the antennas 206b and 306b or between the antennas 206d and 306d.

  First, between the antennas 206c and 306c, the identification information of the RF coil device 100 is wirelessly transmitted from the coil side wireless communication device 200A to the control side wireless communication device 300.

Specifically, the identification information is stored in the ID transmission unit 222 in advance. However, the identification information of the RF coil device 100 may be input from the control circuit 108 to the ID transmitter 222 of the coil-side wireless communication device 200A via the cable 102.
When the antenna 306 c of the ID receiving unit 322 approaches the antenna 206 c of the ID transmitting unit 222, the ID transmitting unit 222 operates based on the power supplied wirelessly from the ID receiving unit 322. That is, the ID transmission unit 222 automatically wirelessly transmits the identification information as a digital signal from the antenna 206c to the antenna 306c. The wireless communication of the identification information may be the same means as RFID (Radio Frequency Identification) represented by an IC tag (Integrated Circuit Tag), for example.

  The ID receiving unit 322 inputs the identification information of the RF coil device 100 received by the antenna 306 c to the system control unit 52. Thereby, the system control unit 52 recognizes information such as which of various RF coil devices such as a chest RF coil device and a shoulder RF coil device is currently connected.

  Second, between the antennas 306d to 206d, the gate signal is continuously wirelessly captured from the gate signal transmission unit 324 of the control-side wireless communication device 300 to the gate signal reception unit 224 of the coil-side wireless communication device 200A during imaging. Sent.

  More specifically, for example, a trap circuit including a PIN diode (p-intrinsic-n Diode) is used as a switch for switching on and off each coil element 106 in the RF coil device 100. The gate signal is a control signal for the switch. The gate signal transmission unit 324 may transmit a trigger signal to the gate signal reception unit 224, and the gate signal may be generated based on the trigger signal in the gate signal reception unit 224.

  During the period in which the RF pulse is transmitted to the subject P, the gate signal input to the RF coil device 100 via the gate signal transmission unit 324, the antennas 306d and 206d, and the gate signal reception unit 224 is normally set to the on level. The During the period when the gate signal is on level, the switch is in the off state, and each coil element 106 is in a state where the loop is interrupted, and the MR signal cannot be detected.

  In the period excluding the period during which the RF pulse is transmitted to the subject P, the off-level gate signal is wirelessly transmitted. During the period in which the gate signal is at the off level, the switch is turned on, and each coil element 106 can detect the MR signal. By such on / off switching of the coil element 106, coupling between the transmission RF coil 28 that transmits the RF pulse to the subject P and the coil element 106 that receives the MR signal from the subject P is prevented. Is done.

  Third, between the antennas 306b and 206b, a digital reference signal is continuously captured from the reference signal transmitting unit 318 of the control-side wireless communication device 300 to the reference signal receiving unit 218 of the coil-side wireless communication device 200A during imaging. Is transmitted wirelessly.

  Specifically, the reference signal is a signal for synchronizing the coil-side radio communication device 200 </ b> A that is the MR signal transmission side and the reference frequency of the system based on the fixed frequency generation unit 406. The reference signal transmission unit 318 generates a reference signal by performing processing such as modulation, frequency conversion, amplification, and filtering on the reference clock signal input from the fixed frequency generation unit 406.

  The fixed frequency generation unit 406 generates a reference clock signal having a constant frequency. The fixed frequency generation unit 406 includes, for example, a highly stable crystal oscillator in order to generate a reference clock signal. The fixed frequency generation unit 406 inputs the reference clock signal to the reference signal transmission unit 318 and the variable frequency generation unit 408. In addition, the fixed frequency generation unit 406 also inputs a reference clock signal to a place where clock synchronization is performed in the MRI apparatus 20A such as the image reconstruction unit 56 and the pulse waveform generation unit 404.

  The variable frequency generation unit 408 includes a PLL (Phase-Locked Loop), a DDS (Direct Digital Synthesizer), a mixer, and the like. The variable frequency generation unit 408 operates based on the reference clock signal. The variable frequency generation unit 408 generates a variable frequency local signal (clock signal) that matches the set value input from the system control unit 52 as the center frequency of the RF pulse.

  For this purpose, the system control unit 52 inputs an initial value of the center frequency of the RF pulse to the variable frequency generation unit 408 before the pre-scan. Further, the system control unit 52 inputs the correction value of the center frequency of the RF pulse to the variable frequency generation unit 408 after the prescan.

  The variable frequency generation unit 408 inputs the variable frequency local signal to the frequency down conversion unit 410 and the frequency up conversion unit 402.

  Further, a trigger signal (A / D conversion start signal) for determining the sampling timing in the A / D converter 212 in the cover member 104 is input from the system control unit 52 to the reference signal transmission unit 318. Sampling here refers to, for example, taking the strength of an analog signal at regular intervals and making it digitally recordable. Here, as an example, the reference signal transmission unit 318 wirelessly transmits both the reference signal and the trigger signal to the reference signal reception unit 218 by superimposing the trigger signal on the reference signal.

  Fourth, between the antennas 206a and 306a, a digital MR signal is wirelessly transmitted from the data transmission unit 216 of the coil-side wireless communication device 200A to the data reception unit 316 of the control-side wireless communication device 300 via an induced electric field. Is done.

  Specifically, in the cover member 104 of the RF coil device 100, a plurality of preamplifiers PMP respectively corresponding to the respective coil elements 106 are arranged in front of each A / D converter 212. The MR signal detected by each coil element 106 of the RF coil device 100 is amplified by each preamplifier PMP, then input to each A / D converter 212 as an analog signal, and converted into a digital signal. At this time, a reference signal and a trigger signal are input from each reference signal receiving unit 218 to each A / D converter 212. Accordingly, each A / D converter 212 starts sampling and quantization based on the reference signal (sampling clock signal) in synchronization with the timing at which the trigger signal is transmitted.

  Each A / D converter 212 inputs a digital MR signal to the P / S converter 214. There are a plurality of MR signals detected by the plurality of coil elements 106 and A / D converted respectively. Therefore, the P / S converter 214 converts the plurality of MR signals from a parallel signal to a serial signal for wireless transmission, and converts the serial signal to the data transmission unit 216 of the coil-side wireless communication device 200A via the cable 102. input. This is because in the example of this embodiment, there is only one antenna 206a for transmitting MR signals.

  However, the present embodiment is not limited to the aspect of wireless transmission as a serial signal. For example, a configuration may be adopted in which the number of antennas for transmitting and receiving MR signals is increased and wireless transmission is performed with parallel signals.

  The data transmission unit 216 performs processing such as error correction coding, interleaving, modulation, frequency conversion, amplification, filtering, etc. on the input serial MR signal, thereby performing wireless transmission (which is a serial signal and a digital signal). A trusted MR signal is generated. The data transmission unit 216 wirelessly transmits an MR signal for wireless transmission from the antenna 206a to the antenna 306a.

  The data receiving unit 316 performs processing such as amplification, frequency conversion, demodulation, deinterleaving, and error correction decoding on the MR signal received by the antenna 306a. As a result, the data receiving unit 316 extracts the original digital MR signal from the MR signal for radio transmission, and inputs the extracted MR signal to the frequency down-conversion unit 410 of the RF receiver 48.

  The frequency down-conversion unit 410 multiplies the local signal input from the variable frequency generation unit 408 by the MR signal input from the data reception unit 316, and further passes only a desired signal band by filtering. As a result, the frequency down-conversion unit 410 frequency-converts (down-converts) the MR signal and inputs the MR signal whose frequency is lowered to the signal processing unit 412.

  The signal processing unit 412 performs raw signal processing to generate raw data of MR signals. The raw data of the MR signal is input to the image reconstruction unit 56, and is converted into k-space data and stored in the image reconstruction unit 56 as described above.

  In the above configuration, the RF receiver 48 and the control-side wireless communication apparatus 300 are described as separate components, but this is only an example. For example, the RF receiver 48 may be a part of the control-side wireless communication device 300.

Further, the gate signal may be superimposed on the reference signal in the same manner as the trigger signal. In this case, since the number of wireless communication paths can be reduced by one by omitting the configurations of the antennas 206d and 306d, the configurations of the coil side wireless communication device 200A and the control side wireless communication device 300 can be simplified.
The above is the description regarding the four wireless communication paths.

  In FIG. 6, the system control unit 52, based on the imaging conditions input by the operator via the input device 62, the repetition time (RF pulse period) in the pulse sequence, the type of RF pulse, the center frequency of the RF pulse, and Imaging conditions such as the bandwidth of the RF pulse are determined. The system control unit 52 inputs the imaging conditions determined as described above to the pulse waveform generation unit 404.

  The pulse waveform generation unit 404 generates a baseband pulse waveform signal using the reference clock signal input from the fixed frequency generation unit 406 in accordance with the imaging conditions input from the system control unit 52 as described above. The pulse waveform generation unit 404 inputs a baseband pulse waveform signal to the frequency up-conversion unit 402.

  The frequency up-conversion unit 402 multiplies the baseband pulse waveform signal by the local signal input from the variable frequency generation unit 408, and further passes only a desired signal band by filtering, thereby performing frequency conversion (up-conversion). Conversion). The frequency up-conversion unit 402 inputs the baseband pulse waveform signal whose frequency is thus increased to the RF transmitter 46. The RF transmitter 46 generates an RF pulse based on the input pulse waveform signal.

  FIG. 7 is a flowchart illustrating an example of a flow of an imaging operation by the MRI apparatus 20A according to the first embodiment. The operation of the MRI apparatus 20A will be described below according to the step numbers shown in FIG.

  In addition, although the example using the said RF coil apparatus 100 is demonstrated here as an example, also when using other RF coil apparatuses, such as those for shoulders and heads, by providing the same configuration as the coil radio communication apparatus 200A. The same effect as in the first embodiment can be obtained.

  [Step S1] With the top plate 34 outside the gantry 21, the RF coil device 100 is mounted on the subject P on the top plate 34. For example, the coil side wireless communication with the control side wireless communication device 300 at the closest position is performed. Communication device 200A is detachably fixed. That is, for example, the coil-side wireless communication device 200A is fitted to the fixing mechanism 500A by sliding the coil-side wireless communication device 200A on the top surface of the top plate 34, or the like. As a result, the coil-side wireless communication device 200A is detachably fixed to any one of the control-side wireless communication devices 300 (see FIGS. 2 to 5).

  When the coil-side wireless communication device 200A and the control-side wireless communication device 300 are within the communicable range due to the proximity fixing, the above-described power supply and wireless communication are started between them.

  Specifically, the ID transmission unit 222 wirelessly transmits the identification information of the RF coil device 100 to the ID reception unit 322 by operating based on the power supplied wirelessly from the ID reception unit 322. Here, for example, the antenna 306 c of each control-side wireless communication device 300 constantly outputs electromagnetic waves at regular time intervals during a period when the top plate 34 is not inserted into the gantry 21. For this reason, when the coil-side wireless communication device 200A is fixed within the communicable range, wireless transmission of the identification information is immediately started.

  The system control unit 52 acquires this identification information and recognizes that the RF coil device 100 is currently connected. As a result, the system control unit 52 permits further communication between the coil-side wireless communication device 200A and the control-side wireless communication device 300, and causes the power supply unit 320 to supply power to the power reception unit 220. For this reason, the power supply unit 320 and the power reception unit 220 start supplying power to each unit of the coil-side wireless communication device 200A and each unit in the cover member 104 via the induction magnetic field as described above.

  In addition, the reference signal transmission unit 318 inputs a digital reference signal to the reference signal reception unit 218 through, for example, a wireless communication path via the induction electric field between the antennas 306b and 206b in accordance with the communication permission by the system control unit 52. (The reference signal is continuously transmitted by radio). Note that a trigger signal for determining sampling timing is also superimposed (added) on the transmitted reference signal.

  Thereafter, the top board driving device 32 (see FIG. 1) slides the top board 34 into the gantry 21 according to the control of the system control unit 52. Thereafter, the process proceeds to step S2.

  [Step S2] The system control unit 52 captures the imaging conditions input to the MRI apparatus 20A via the input device 62 and information on the coil used in step S1 (in this example, the RF coil device 100 is used). Based on the above, a part of the imaging conditions for the main scan is set. Thereafter, the process proceeds to step S3.

  [Step S3] The system control unit 52 controls each unit of the MRI apparatus 20A to execute a pre-scan. In the prescan, for example, a correction value of the center frequency of the RF pulse is calculated, and a sensitivity distribution map of each coil element 106 in the RF coil device 100 is generated. Thereafter, the process proceeds to step S4.

[Step S4] The system control unit 52 sets the remaining imaging conditions for the main scan based on the execution result of the pre-scan. The imaging conditions include information on which coil element 106 is used for reception in the main scan.
Therefore, the system control unit 52 inputs, for example, information on the coil element used for reception in the main scan to the control circuit 108 of the RF coil device 100 through any wireless communication path. Information on the coil element 106 used for reception is, for example, wirelessly transmitted from the gate signal transmission unit 324 to the gate signal reception unit 224 and then input from the gate signal reception unit 224 to the control circuit 108. Thereafter, the process proceeds to step S5.

  [Step S5] The system control unit 52 controls each unit of the MRI apparatus 20A to execute the main scan. Specifically, a static magnetic field is formed in the imaging space by the static magnetic field magnet 22 excited by the static magnetic field power supply 41. Further, a current is supplied from the shim coil power source 42 to the shim coil 24, and the static magnetic field formed in the imaging space is made uniform. Note that during execution of the main scan, the above-described gate signal is continuously wirelessly transmitted from the gate signal transmission unit 324 to the gate signal reception unit 224 between the antennas 306d and 206d.

  Thereafter, when an imaging start instruction is input from the input device 62 to the system control unit 52, MR signals from the subject P are collected by sequentially repeating the following processes <1> to <4>. .

  <1> The system control unit 52 drives the gradient magnetic field power supply 44, the RF transmitter 46, and the RF receiver 48 according to the pulse sequence, thereby forming a gradient magnetic field in the imaging region including the imaging region of the subject P. The RF pulse is transmitted from the transmission RF coil 28 to the subject P. Only during the period in which the RF pulse is transmitted to the subject P, the gate signal is turned on, for example, and the coil elements 106 of the RF coil device 100 are turned off, preventing the above-described coupling.

  <2> After the RF pulse is transmitted, the gate signal is switched to, for example, an off level, and each coil element 106 detects an MR signal generated by nuclear magnetic resonance in the subject P. The detected analog MR signal is input from each coil element 106 to each preamplifier PMP, amplified, and then input to each A / D converter 212 (see FIG. 6).

  However, here, as an example, the control circuit 108 of the RF coil device 100 operates only each preamplifier PMP and each A / D converter 212 corresponding to each coil element 106 selected for reception in step S4. That is, each preamplifier PMP and each A / D converter 212 corresponding to the non-selected coil element 106 does not operate. Thereby, only the MR signal detected by the coil element 106 selected for receiving the MR signal is wirelessly transmitted to the control side of the MRI apparatus 20A. For this reason, since MR signals that are not used for image reconstruction are not transmitted wirelessly, the data transmission amount of MR signals can be kept to a minimum, so that the data transmission time is not unnecessarily prolonged.

  However, MR signals detected by all the coil elements 106 in the RF coil apparatus 100 are wirelessly transmitted to the control side of the MRI apparatus 20A, and only the necessary MR signals are extracted by the RF receiver 48 or the image reconstruction unit 56. It may be configured. In this case, in step S4, the process of inputting information on the coil elements used for reception in the main scan from the system control unit 52 to the control circuit 108 of the RF coil device 100 is not necessary.

  <3> Each A / D converter 212 corresponding to each coil element 106 selected for reception samples and quantizes the MR signal based on the reference signal in synchronization with the timing at which the trigger signal is wirelessly transmitted. To start. Each A / D converter 212 inputs a digital MR signal to the P / S converter 214.

  The P / S converter 214 converts the plurality of input MR signals into serial signals and inputs them to the data transmission unit 216. The data transmission unit 216 performs a predetermined process on the serial MR signal to generate an MR signal for wireless transmission, and wirelessly transmits the MR signal from the antenna 206a to the antenna 306a via an induction electric field.

  <4> The data receiving unit 316 extracts the original digital MR signal by performing predetermined processing on the MR signal for radio transmission received by the antenna 306a, and inputs the extracted MR signal to the frequency down-conversion unit 410. To do. The frequency down-conversion unit 410 performs frequency down-conversion of the input MR signal, and inputs the MR signal whose frequency is reduced to the signal processing unit 412. The signal processing unit 412 performs raw signal processing to generate raw data of MR signals. The raw data of the MR signal is input to the image reconstruction unit 56, converted into k-space data by the image reconstruction unit 56, and stored.

  By repeating the processes <1> to <4>, the process proceeds to step S6 after the acquisition of the MR signals is completed.

  [Step S6] The image reconstruction unit 56 reconstructs image data by performing image reconstruction processing including Fourier transform on k-space data, and the obtained image data is stored in the image database 58 (see FIG. 1). save. Thereafter, the process proceeds to step S7.

  [Step S <b> 7] The image processing unit 60 takes in image data from the image database 58, performs predetermined image processing on the image data, generates display image data, and stores the display image data in the storage device 66. The system control unit 52 transfers the display image data to the display device 64 and causes the display device 64 to display the image indicated by the display image data.

  After the imaging is finished, the coil-side wireless communication device 200A is pulled away from the fixing mechanism 500A by sliding the projection 240a on the top surface of the top plate 34 in the direction in which the protrusion 240a is extracted from the insertion port 506. As a result, when the coil-side wireless communication device 200A is detached from the control-side wireless communication device 300 and both of them are out of the communicable range, the communication and power supply between the two ends.

In FIG. 7, as an example, the input of the reference signal is started in step S1, but this is only an example. For example, the input of the reference signal may be started immediately before the pre-scan in step S3 (that is, after the imaging condition is set in step S2).
The above is the description of the operation of the MRI apparatus 20A of the first embodiment.

  As described above, in the first embodiment, the transmission side and the reception side are fixed in proximity to each other during wireless communication, and wireless communication is performed via an induced electric field. For this reason, since the wireless output can be kept lower than conventional digital wireless communication, it is easy to comply with the laws and regulations of various countries.

  In addition to the proximity of the transmission side and the reception side, the wireless output can be lowered. For this reason, there is no problem that the transmission radio waves are reflected around and the transmission data is deteriorated. Therefore, a digital MR signal can be satisfactorily transmitted wirelessly from the RF coil apparatus 100 side to the main body side (RF receiver 48 side) of the MRI apparatus 20A.

  The plurality of MR signals detected by the plurality of coil elements 106 are converted into serial signals and transmitted wirelessly. Therefore, one set of antennas (radio communication paths) for transmitting MR signals can be used, and it is not necessary to perform frequency separation for preventing interference between MR signals.

  On the other hand, in the conventional digital wireless communication, since the receiving side exists in the far field on the transmitting side, interference occurs such as crosstalk when a plurality of coil elements for receiving MR signals are connected simultaneously. Frequency separation and time division communication are performed. In short-distance wireless communication as in the present embodiment, time division is not necessary.

  Further, the control-side wireless communication device 300 may be provided at a plurality of locations, and the coil-side wireless communication device 200A may be fixed to any one of the control-side wireless communication devices 300. Accordingly, regardless of the position of the RF coil device mounted on the subject P, that is, the position of the RF coil device 100 on the top plate 34, the coil-side wireless communication device 200A and the control-side wireless The communication apparatus 300 can be fixed in proximity and MR signals can be transmitted wirelessly satisfactorily.

  Further, since the fixing mechanism 500A serves as a mark, it is easy to position the coil-side wireless communication device 200A at a position where wireless communication with any one of the control-side wireless communication devices 300 is possible. Furthermore, since the coil-side wireless communication device 200A can be detachably and reliably fixed to the control-side wireless communication device 300 by the fixing mechanism 500A, communication obstruction due to human error can be reliably prevented.

  Since power supply to the RF coil device 100, transmission of the gate signal, and transmission of the trigger signal are also performed wirelessly, the configuration of the MRI apparatus can be simplified. As a result, the manufacturing cost of the MRI apparatus can be reduced.

  According to the embodiments described above, in MRI, digitized MR signals can be satisfactorily transmitted wirelessly from the RF coil apparatus to the MRI apparatus. Further, since the coil-side wireless communication device can be fixed to the control-side wireless communication device by a more reliable method, communication hindrance due to human error can be prevented.

  Hereinafter, supplementary items of the first embodiment will be described. The example in which the insertion port 506 of the fixing mechanism 500A and the protrusion 240a of the coil-side wireless communication device 200A are one each has been described. The embodiment of the present invention is not limited to such an aspect. There may be a plurality of insertion holes 506 and protrusions 240a.

  The example in which the protrusion 240a has a cylindrical shape and the insertion port 506 has a shape in which the protrusion 240a is fitted is described. The embodiment of the present invention is not limited to such an aspect. The protrusion 240a may have a rectangular parallelepiped shape, for example, or may be tapered to facilitate insertion. As long as the protrusion 240a can be detachably fixed, the outer shape of the insertion port 506 does not need to match the contour of the protrusion 240a. For example, the protrusion 240a may have a rectangular parallelepiped shape, and the insertion port 506 may have a shape opened in a circular shape. In addition, the inner surface of the insertion port 506 is not smooth and may have irregularities for ensuring with frictional force.

  An example has been described in which the support member 502a of the fixing mechanism 500A is L-shaped, and only one of the four side surfaces of the coil-side wireless communication device 200A is in close contact with the support member 502a when fixed. The embodiment of the present invention is not limited to such an aspect. The support member 502a may have a shape opened only on the side surface into which the coil-side wireless communication device 200A is inserted, for example, as in a fixing mechanism 500D of a fourth embodiment described later. When the coil-side wireless communication device 200A is slid toward the fixing mechanism 500A, the L-shaped approach is easier to approach from many directions.

  Moreover, the structure which provided the processus | protrusion in the supporting member 502a side of 500 A of fixing mechanisms, and the insertion port which fits this processus | protrusion was formed in the housing of coil side radio | wireless communication apparatus 200A may be sufficient.

<Second Embodiment>
Next, the MRI apparatus 20A of the second embodiment will be described. The MRI apparatus 20A of the second to fifth embodiments is different from the first embodiment only in the fixing mechanism for fixing the coil side wireless communication apparatus, and only the differences will be described.

  FIG. 8 is a schematic perspective view showing a fixing mechanism 500B for fixing the coil-side radio communication device 200B in the MRI apparatus 20A of the second embodiment. As shown in FIG. 8, in the coil side wireless communication device 200B, the casing 202b has, for example, a rectangular parallelepiped shape, and the protrusions 240b are fixed to the four corners of the bottom surface. The fixing method may be, for example, adhesion or may be formed integrally with the housing 202b. Each protrusion 240b is formed, for example, in a cylindrical shape from a non-magnetic material that does not deform.

  The top plate 34 is provided with four fixing mechanisms 500B. Each fixing mechanism 500B is located slightly outside the four corners of the control-side wireless communication device 300 embedded in the top plate 34 as in the first embodiment. Each fixing mechanism 500B is formed in a cylindrical shape by a material having elasticity such as silicone rubber, polyethylene, or synthetic resin. In other words, a circular opening is formed in the center of each fixing mechanism 500B. These insertion openings 514 are contours for fitting the protrusions 240b.

  FIG. 9 is a schematic cross-sectional view of a state in which each protrusion 240b of the coil-side wireless communication device 200B is fitted to each fixing mechanism 500B of the top plate 34. As illustrated in FIG. 9, the coil-side wireless communication device 200 </ b> B is detachably fixed at a position facing the control-side wireless communication device 300 only by inserting each protrusion 240 b through each fixing mechanism 500 </ b> B. The antennas 206a to 206d of the coil-side radio communication device 200B are arranged so as to be opposed to the antennas 306a to 306d of the control-side radio communication device 300 in this fixed state.

Further, since each protrusion 240b is inserted into each fixing mechanism 500B provided outside the control-side wireless communication apparatus 300, the area of the bottom surface (surface on the antenna side) of the housing 202b is the upper surface (the surface of the control-side wireless communication apparatus 300). It is larger than the area of the antenna side surface).
When the imaging is completed, the coil-side wireless communication device 200B may be lifted in the direction away from the top board 34. Other configurations of the MRI apparatus 20A of the second embodiment are the same as those of the first embodiment.

  As described above, also in the second embodiment, the coil-side wireless communication device 200B can be detachably and securely fixed at a position where wireless communication with the control-side wireless communication device 300 via the induction electric field is possible. Therefore, also in the second embodiment, the same effect as in the first embodiment can be obtained. Furthermore, in the second embodiment, since it is the fixing mechanism 500B in which the insertion port 514 is formed in the top plate 34, there is no protruding portion on the top plate 34. Therefore, the second embodiment is advantageous when it is desired to make the upper surface of the top plate 34 more planar.

<Third Embodiment>
Next, an MRI apparatus according to a third embodiment will be described.
FIG. 10 is a schematic cross-sectional view of a fixing mechanism 500C in a state where the coil-side radio communication device 200C is not fixed in the MRI apparatus 20A of the third embodiment.
FIG. 11 is a schematic cross-sectional view of a fixing mechanism 500C in a state where the coil-side radio communication device 200C is fixed in the MRI apparatus 20A of the third embodiment.
From the state shown in FIG. 10, the coil-side wireless communication device 200 </ b> C is slid to the back side of the fixing mechanism 500 </ b> C on the upper surface of the top plate 34 to be in the fixed state shown in FIG.

  As shown in FIG. 11, in the coil-side wireless communication device 200C, the side surface of the casing 202c opposite to the exposed surface of the cable 102 is inclined toward the upper surface (the surface opposite to the antennas 206a to 206d). It is chamfered. As shown in FIG. 10, the coil side wireless communication device 200C is easily inserted into the fixing mechanism 500C. Moreover, the hollow part 250 is formed in the upper surface of the housing 202c.

  The fixing mechanism 500 </ b> C provided on the top plate 34 includes a support member 502 c, a protrusion 524, a spring 526, a fitting sensor 528, and a notification unit 530.

  Similar to the support member 502a of the first embodiment, the support member 502c has a substantially L-shaped cross section made of a non-deformable material and is fixed to the top surface of the top plate 34. . The protrusion 524 has a front end protruding from the support member 502c and a rear end embedded in the support member 502c. The protrusion 524 has, for example, a shape in which only the front end side of the cylinder is chamfered into a spherical shape. The tip side of the protrusion 524 has a shape that fits into the recess 250.

The spring 526 is attached to the rear end side of the protrusion 524 and presses the protrusion 524 toward the top plate 34 side. That is, in the state of FIG. 10 in which the coil-side wireless communication device 200C is not fixed to the fixing mechanism 500C, the spring 526 is in the most extended state, and thus the protrusion 524 is in the state of most protruding from the support member 502c.
On the contrary, in the state of FIG. 11 in which the coil-side wireless communication device 200C is fixed to the fixing mechanism 500C, the tip of the protrusion 524 is fitted into the recess 250, and the support member 502c is more than in the state of FIG. Enter inside.

  10 and 11, the thickness of the space between the support member 502c and the top plate 34 is equal to the thickness of the housing 202c.

  The fitting sensor 528 detects that the coil-side wireless communication device 200C is fixed by the fixing mechanism 500C by detecting a state in which the protrusion 524 enters the inside of the support member 502c as shown in FIG. When it is detected that the coil-side wireless communication device 200C is fixed to the fixing mechanism 500C, the fitting sensor 528 inputs a signal indicating that the coil-side wireless communication device 200C is fixed to the notification unit 530.

  In addition, the antennas 206a to 206d of the coil-side wireless communication device 200C are disposed so as to face the antennas 306a to 306d of the control-side wireless communication device 300 in the fixed state of FIG. Therefore, when the coil side wireless communication device 200C is fixed as described above, the identification information of the RF coil device 100 is transmitted from the coil side wireless communication device 200C to the control side wireless communication device 300 between the antennas 206c and 306c as described above. To the system control unit 52.

  When the system control unit 52 accurately recognizes the identification information and issues a communication permission between the coil-side wireless communication device 200C and the control-side wireless communication device 300, the system control unit 52 also transmits a signal indicating the communication permission to the notification unit 530. input. The fact that the identification information has been received correctly has ensured that the wireless communication strength is such that wireless communication via the induction electric field is possible between the coil-side wireless communication device 200C and the control-side wireless communication device 300. Because it means.

The notification unit 530 includes a light emitting diode 532. When the following two conditions are satisfied, the notification unit 530 notifies information indicating that wireless communication via an induction electric field between the coil-side wireless communication device 200C and the control-side wireless communication device 300 is possible. .
The first condition is that a signal indicating that the coil-side wireless communication device 200 </ b> C is fixed is input from the fitting sensor 528 to the notification unit 530.
The second condition is that a signal indicating the communication permission is input from the system control unit 52 to the notification unit 530.

  The notification of the information indicating that wireless communication is possible is visually performed here by causing the light emitting diode 532 to emit light, but this is only an example. The notification of information indicating that wireless communication has become possible may be performed audibly, for example. Specifically, the notification unit 530 may automatically output a voice indicating that wireless communication is possible. Alternatively, the notification unit 530 may output a beep sound.

  Further, the present embodiment is not limited to the form of notifying the information that wireless communication is possible when the above two conditions are satisfied. For example, the notification unit 530 may notify the information that the wireless communication is possible when the fitting sensor 528 is omitted and the second condition is satisfied.

  When imaging is completed, the coil-side wireless communication device 200C may be slid on the top plate 34 in a direction away from the fixing mechanism 500C. Other configurations of the MRI apparatus 20A of the third embodiment are the same as those of the first embodiment.

  As described above, also in the third embodiment, the coil-side radio communication device 200C can be detachably and reliably fixed at a position where radio communication with the control-side radio communication device 300 via the induction electric field is possible. Therefore, also in the third embodiment, the same effect as in the first embodiment can be obtained. Furthermore, in the third embodiment, when wireless communication via the induction electric field between the coil-side wireless communication device 200C and the control-side wireless communication device 300 becomes possible, this is visually indicated to the user. Be notified. Therefore, in the third embodiment, user convenience is further improved.

<Fourth Embodiment>
Next, an MRI apparatus 20A of the fourth embodiment will be described. The fourth embodiment is different from the first embodiment in the installation location of the rechargeable battery BA and the fixing method of the coil-side radio communication device 200D.

  FIG. 12 is a block diagram showing the functions of the respective units related to the transmission of the MR signal detected by the coil element 106 in the MRI apparatus 20A of the fourth embodiment, as in FIG. As shown in FIG. 12, in the fourth embodiment, the rechargeable battery BA is disposed not in the cover member 104 'of the RF coil device but in the coil-side wireless communication device 200D. Therefore, all the components of the power receiving unit 220 'are arranged in the coil side wireless communication device 200D.

  The stored power of the rechargeable battery BA is supplied to each element in the coil-side radio communication device 200D and is also supplied to each component in the cover member 104 'via a cable 102 (not shown). Other configurations in the cover member 104 'are the same as those in the first embodiment.

  FIG. 13 is a schematic perspective view of a fixing mechanism 500D in a state where the coil-side radio communication device 200D is not fixed in the MRI apparatus 20A of the fourth embodiment. FIG. 14 is a schematic cross-sectional view of a fixing mechanism 500D in a state where the coil-side radio communication device 200D is fixed in the MRI apparatus 20A of the fourth embodiment.

  As shown in FIG. 13, the fixing mechanism 500 </ b> D provided on the top plate 34 includes a housing 538 and an anti-slip sheet (anti-slip member) 540. The casing 538 has a square bracket shape in cross section. The housing 538 is fixed to the upper surface of the top plate 34 with the recessed side thereof being the top plate 34 side. This fixing method is the same as in the first embodiment. Only one end side of the gap 542 formed between the casing 538 and the top plate 34 is opened, and the other end side is not opened (see FIG. 14). The housing 538 is formed of a non-magnetic material that does not deform.

  The casing 202d of the coil side wireless communication device 200D has a substantially rectangular parallelepiped shape, and the cable 102 protrudes from one side surface thereof. The casing 202d has a shape in which both ends of the side surface opposite to the exposed surface of the cable 102 are chamfered like a cylindrical side surface. This is because the width of the casing 202d (WIDTH indicated by a one-dot chain line in FIG. 13) is equal to the width of the gap 542, so that the casing 202d can be easily inserted into the gap. Therefore, the coil-side wireless communication device 200D is inserted into the fixing mechanism 500D with the chamfered side facing the back of the gap 542.

  The anti-slip sheet 540 is fixed on the top surface of the top plate 34 in a gap 542 between the housing 538 and the top plate 34. The anti-slip sheet 540 is formed by providing irregularities on the surface of a material such as silicone rubber. As shown in FIG. 14, a control-side wireless communication device 300 is embedded immediately below the anti-slip sheet 540 on the top plate 34.

  Further, the fixing mechanism 500D is configured such that the width of the gap 542 is equal to the width (WIDTH) of the casing 202d of the coil-side wireless communication device 200D, and the depth of the gap 542 is equal to the depth (DEPTH) of the casing 202d. The housing 538 is formed (see the one-dot chain line in FIG. 13). Accordingly, the coil-side radio communication device 200D is supported by placing the coil-side radio communication device 200D on the non-slip sheet 540 after inserting the coil-side radio communication device 200D to the innermost part of the gap 542.

  Specifically, since the casing 538 is formed in the above-described dimensions, even if the cable 102 is moved by the movement of the subject P during imaging, the coil-side wireless communication in the width direction is performed. The device 200D does not move. Further, since the back side of the gap 542 is not open, the coil-side wireless communication device 200D does not move toward the back side of the gap 542.

  Further, since the coil-side wireless communication device 200D is placed on the non-slip sheet 540, the coil-side wireless communication device 200D is prevented from moving to the entrance side of the gap 542 due to the frictional force between them. In particular, in 4th Embodiment, since the rechargeable battery BA is arrange | positioned in the coil side radio | wireless communication apparatus 200D, the weight of the coil side radio | wireless communication apparatus 200D is increasing. Therefore, the above-described frictional force is strengthened by adding the own weight of the coil-side wireless communication device 200D to the vertical drag.

  Further, the coil-side wireless communication device 200D is prevented from moving upward in the vertical direction (in a direction away from the non-slip sheet 540) by the weight of the coil-side wireless communication device 200D. In the fourth embodiment, the rechargeable battery BA is incorporated in the coil-side wireless communication device 200D in order to increase the above effectiveness.

  The antennas 206a to 206d of the coil-side radio communication device 200D are arranged so as to be opposed to the antennas 306a to 306d of the control-side radio communication device 300 in the fixed state of FIG.

  Here, as an example, the housing 538 is formed so that the thickness of the gap 542 is about two human fingers thicker than the thickness of the coil-side wireless communication device 200D (the one-dot chain line in FIG. 13). THICKNESS). This is because it is difficult to slide the coil-side wireless communication device 200D on the top plate 34 and insert the coil-side wireless communication device 200D into the gap 542 due to the frictional force of the non-slip sheet 540, so the coil-side wireless communication device 200D is inserted into the gap 542. This is to make it easier.

  Even when the coil-side wireless communication device 200D is fixed in the fixing mechanism 500D, the coil-side wireless communication device 200D can be easily taken out by preventing a part of the gap 542 from being filled.

  As described above, also in the fourth embodiment, the coil-side radio communication device 200D can be detachably held at a position where radio communication with the control-side radio communication device 300 via the induction electric field is possible. Therefore, also in the fourth embodiment, the same effect as in the first embodiment can be obtained. In FIG. 13, as an example, a part of the casing 202d of the coil side wireless communication device 200D is smoothly chamfered, but this is not essential. That is, in the fourth embodiment, there is a merit that processing on the casing 202d of the coil-side wireless communication device 200D is unnecessary.

  Note that, when the following two conditions are satisfied, the fixing mechanism 500D may be configured with only the anti-slip sheet 540 without the casing 538. The first condition is that the frictional force between the casing 202d of the coil-side radio communication apparatus 200D and the anti-slip sheet 540 is sufficient, and there is no possibility that the casing 202d moves in parallel with the upper surface of the top plate 34. The second condition is that the weight of the casing 202d of the coil side wireless communication device 200D is sufficient, and there is no possibility that the casing 202d moves upward in the vertical direction.

  Alternatively, in order to completely eliminate the possibility of the casing 202d moving upward in the vertical direction, the following modifications may be configured.

  FIG. 15 is a schematic cross-sectional view of a fixing mechanism 500D ′ according to a modification of the fourth embodiment. FIG. 15 shows a state where the flat plate 544 is inserted into a portion where the gap 542 is not buried after the coil-side radio communication device 200D is inserted and fixed to the innermost part of the gap 542 as shown in FIG.

  The width of the flat plate 544 is, for example, equal to the width of the gap 542 or slightly smaller than the width of the gap 542. The depth of the flat plate 544 is longer than the depth of the gap 542. This is because the flat plate 544 can be easily taken out.

  Further, one end side of the flat plate 544 is chamfered like a side surface of a cylinder so that it can be easily inserted into the gap 542. The thickness of the flat plate 544 is equal to the difference between the thickness of the gap and the thickness of the casing 202d of the coil-side wireless communication device 200D. Therefore, by inserting the flat plate 544 above the coil-side radio communication device 200D in the gap 542, the possibility that the coil-side radio communication device 200D moves upward in the vertical direction is completely eliminated.

<Fifth Embodiment>
Next, an MRI apparatus 20A of the fifth embodiment will be described. The fifth embodiment is different from the first to fourth embodiments in that the coil side wireless communication device 200E is fixed by suction.

  FIG. 16 is a schematic cross-sectional view of a fixing mechanism 500E in the MRI apparatus 20A of the fifth embodiment. The fixing mechanism 500E includes a suction unit 550, a plurality of suction pipes 552, and a plurality of suction ports 554. For example, the number of suction tubes 552 is the same as the number of control-side wireless communication devices 300 in the top plate 34. That is, the suction pipe 552 is provided in the top plate 34 corresponding to each control-side wireless communication device 300. Here, as an example, the number of suction ports 554 is four times the number of suction tubes 552. That is, four suction ports 554 are formed on the top surface of the top plate 34 corresponding to each control-side wireless communication device 300 (FIG. 16 is a cross-section, so only two suction ports 554 are provided for each suction tube 552. Is shown).

  In FIG. 16, the suction part 550 is provided in the support base 31, but this is only an example. For example, when the top plate 34 has a sufficient thickness, the fixing mechanism 500E may be provided on the top plate 34 by embedding the suction portion 550 in the top plate 34.

  FIG. 17 is a schematic top view of a portion of the top board 34 in a state where the coil-side radio communication device 200E is not fixed. As shown in FIG. 17, four suction ports 554 are formed slightly outside the four corners of the control-side wireless communication device 300 embedded in the top plate 34. These four suction ports 554 are connected to one suction pipe 552. Further, a guide frame 556 for positioning when placing the coil-side wireless communication device 200E is shown on the top plate 34 by painting or the like (a two-dot chain line frame in the figure). The size and shape of the guide frame 556 match the contour of the bottom surface of the casing of the coil-side wireless communication device 200E.

  18 is a schematic top view showing a state where the coil side wireless communication device 200E is placed on the top board 34 so as to block the four suction ports 554 from the state of FIG. That is, by placing the coil side wireless communication device 200E on the top plate 34 so that the contour of the coil side wireless communication device 200E matches the guide frame 556, the suction operation is started as follows.

  Specifically, the antennas 206a to 206d in the coil-side wireless communication device 200E are mutually connected to the antennas 306a to 306d of the control-side wireless communication device 300 when the coil-side wireless communication device 200E is placed as described above. It is arranged at the opposite position. Therefore, when the coil-side wireless communication device 200E is placed at the above position, the identification information of the RF coil device 100 is wirelessly transmitted from the coil-side wireless communication device 200E to the control-side wireless communication device 300 as described above. Input to the controller 52. At this time, the system control unit 52 also determines and stores information indicating which control-side wireless communication device 300 is the transfer source of the identification information.

  When the system control unit 52 accurately recognizes the identification information and issues a communication permission between the coil-side wireless communication device 200E and the control-side wireless communication device 300 that is the transfer source of the identification information, the communication permission is granted. Is also input to the suction unit 550. Thereby, a shutter (not shown) between the suction pipe 552 connected to the four suction ports 554 closed by the coil-side wireless communication device 200E and the inside of the suction unit 550 is opened. The shutter between the other suction pipe 552 and the inside of the suction part 550 remains closed.

  Next, the suction unit 550 exhausts air in the suction unit 550 toward the outside of the suction unit 550 by rotating a fan (blade) at a high speed by a motor (not shown). As a result, the pressure in the suction unit 550 becomes lower than the outside, and air is sucked from the suction port 554 directly below the coil-side wireless communication device 200E through the suction pipe 552 opened by the shutter. The coil-side wireless communication device 200E is fixed by such suction.

  Here, the fact that the control-side wireless communication device 300 (and the system control unit 52) has correctly received (recognized) the identification information indicates that the wireless communication between the coil-side wireless communication device 200E and the control-side wireless communication device 300 is performed. This means that the communication strength has reached a predetermined value or more. This is because the identification information cannot be received correctly unless the wireless communication strength is less than the predetermined value. Therefore, it can be said that the suction operation by the fixing mechanism 500E is automatically started when the wireless communication strength between the coil-side wireless communication device 200E and the control-side wireless communication device 300 becomes a predetermined value or more.

  Next, a method for stopping the suction operation will be described. As for the stopping method, for example, a suction stop button may be provided near each guide frame 556 on the top surface of the top plate 34, and the suction may be stopped when the button is pressed. In the present embodiment, as an example, the suction unit 550 automatically stops the suction at the timing when the top plate 34 returns to a predetermined position on the support base 31.

FIG. 19 is a schematic diagram for explaining the timing of automatic stop of the suction operation together with the flow of movement of the top board 34. In FIG. 19, as an example, the flow of movement of the top plate 34 is shown in four stages in order from the top.
The top row in FIG. 19 is before the start of pre-scanning, and is a state where the height of the support base 31 is lowered. For example, in this state, the subject P is placed on the top plate 34 of the bed apparatus 30 and the RF coil device 100 is mounted on the subject P. Thereafter, the coil-side wireless communication device 200E at the tip of the cable 102 of the RF coil device 100 is placed so as to match the guide frame 556 of FIG. Thereby, the above-described suction operation is started.

  Next, the top plate driving device 32 raises the height of the support base 31 so that the height of the top plate 34 matches the height of the rail 470 in the gantry 21 according to the control of the system control unit 52. The second from the top in FIG. 19 shows this state. Note that the mounting of the RF coil device 100 on the subject P and the operation of placing the coil-side wireless communication device 200E at a predetermined position may be performed in a state where the height of the support base 31 is thus raised.

  Next, the top board driving device 32 slides the top board 34 on which the subject P is placed in the gantry 21 along the rail 470 in the horizontal direction under the control of the system control unit 52. At this time, the horizontal position of the couchtop 34 is controlled so that the imaging region of the subject P is positioned at the center of the magnetic field in the gantry 21. Here, the horizontal direction is the Z-axis direction of the above-described apparatus coordinate system. The third from the top in FIG. 19 shows this state. In this state, the pre-scan and the main scan are executed as described in the first embodiment.

  Next, when the main scan is finished, the top board driving device 32 slides the top board 34 on which the subject P is placed in the horizontal direction along the rail 470 according to the control of the system control unit 52, and the support base 31. Return to the side. The lowermost stage in FIG. 19 shows a state in which one end side of the top plate 34 has returned to a predetermined position. The predetermined position here is, for example, a position where the top plate 34 is farthest from the gantry 21, and in the example of FIG. 19, is the rear end (BACK END) of the support base 31 indicated by a one-dot chain line.

  In the present embodiment, as an example, when the one end side of the top plate 34 returns to the predetermined position, the top plate driving device 32 inputs a signal indicating that to the suction unit 550. For this reason, the suction part 550 automatically stops the suction operation in synchronization with the timing when the one end side of the top plate 34 returns to the predetermined position (the rear end of the support base 31).

  Note that the above is merely an example, and the suction unit 550 may automatically stop the suction operation in synchronization with the timing at which the top 34 is completely removed from the gantry 21 and the movement of the top 34 is stopped. “The state in which the top plate 34 has completely come out of the gantry 21 and the movement of the top plate 34 has stopped” means a state in which the height of the support 31 can be changed, that is, a state in which the top plate 34 can be moved up and down. is there.

  The above is the description of the suction operation, but the suction mechanism is not limited to the above form. The suction unit 550 may be, for example, a hydraulic suction pump.

  As described above, also in the fifth embodiment, the coil-side wireless communication device 200E can be detachably and reliably fixed at a position where wireless communication via the induction electric field with the control-side wireless communication device 300 is possible. Therefore, also in the fifth embodiment, the same effect as in the first embodiment can be obtained.

  Further, in the fifth embodiment, since the coil-side wireless communication device 200E is fixed by suction, similarly to the fourth embodiment, there is an advantage that processing on the casing of the coil-side wireless communication device 200E is unnecessary.

  Further, in the fifth embodiment, the suction operation is automatically stopped in synchronization with the timing when the main scan is completed and the top plate 34 returns to a predetermined position on the support base 31. Therefore, it is possible to simplify the trouble of releasing the connection after imaging.

  In the fifth embodiment, the example in which the coil side wireless communication device 200E is fixed by the four suction ports 554 is described, but this is only an example. The coil-side wireless communication device 200E may be fixed by one, two, three, or five or more suction ports. Further, although the example in which the suction port 554 is formed outside the control-side wireless communication device 300 has been described, this is merely an example.

FIG. 20 shows the modification of the fifth embodiment as a fixing mechanism 500E ′ in which the coil-side radio communication device 200E is attached to the top plate 34 so as to match the guide frame 556 when there is only one suction port 554 ′. It is a cross-sectional schematic diagram which shows the state put on the upper surface.
FIG. 21 is a schematic top view of the top plate 34 in the state of FIG.

  In this modification, as shown in FIG. 21, an insertion port 330 is formed at the center of the control-side wireless communication device 300 '. Other configurations of the control-side wireless communication device 300 ′ are the same as those of the control-side wireless communication device 300 of the first embodiment. The suction tube 552 ′ passes through the insertion port 330 and is connected to a suction port 554 ′ formed on the upper surface of the top plate 34. Even in such a configuration, the same effects as those of the embodiment described with reference to FIGS.

<Sixth Embodiment>
Next, an MRI apparatus 20B according to a sixth embodiment will be described. The MRI apparatus 20B of the sixth embodiment includes any one of the fixing mechanisms 500A to 500E of the first to fifth embodiments (which may be any) and the corresponding coil-side wireless communication apparatuses (200A to 200E). Any). Thereby, the coil side radio | wireless communication apparatus (any of 200A-200E) is fixed (supported) detachably on the top plate 34. FIG. Therefore, the same effect as the first to fifth embodiments can be obtained.

  One of the features of the MRI apparatus 20B of the sixth embodiment is a mechanism in which a plurality of digitized MR signals are combined into one and then input to the RF receiver 48. Hereinafter, a specific configuration for realizing this mechanism and its advantages will be described.

  FIG. 22 is a block diagram showing the overall configuration of the MRI apparatus 20B in the sixth embodiment. Differences from the first embodiment are the following two points, and the other parts of FIG. 22 are the same as those of the MRI apparatus 20A of the first embodiment.

  First, the RF receiver 48 is located in the gantry 21 rather than in the controller 40 '. The transmission of the raw data of the (digital) MR signal from the RF receiver 48 to the image reconstruction unit 56, that is, the output to the outside of the gantry 21, is transmitted as an optical digital signal using, for example, an optical communication cable. May be. In this case, the influence of external noise is reduced.

  Secondly, a signal combining unit 580 that combines a plurality of digitized MR signals into one is arranged in the support table 31 ′ of the dockable bed apparatus 30 ′. Therefore, the digital MR signal wirelessly transmitted to the control-side wireless communication apparatus 300 is input to the signal combining unit 580. The function of the signal synthesis unit 580 will be described with reference to FIG.

  In addition, in order to make the advantage of this embodiment easy to understand, it is assumed that a plurality of RF coil devices are attached to the subject P. In the example of FIG. 22, for example, the cover member 104 ′ of the RF coil device 100 ′ for the lumbar region is attached to the subject P in addition to the cover member 104 of the RF coil device 100 for the chest described above.

  The coil-side wireless communication device (200A to 200E, which is complicated but is omitted from the following because it is complicated) at the tip of the cable 102 of the RF coil device 100 is one control-side wireless communication device in the top board 34. Proximity to 300 is fixed. Further, the coil-side wireless communication device at the tip of the cable of the RF coil device 100 ′ is fixed in proximity to another control-side wireless communication device 300 in the top plate 34.

  FIG. 23 is a block diagram schematically illustrating functions of respective units related to transmission of MR signals detected by the coil elements 106 and 106 ′ of the RF coil devices 100 and 100 ′ according to the sixth embodiment.

  In FIG. 23, the cover member 104 'belongs to the RF coil device 100'. In the cover member 104 ′, a plurality of coil elements 106 ′ and a plurality of preamplifiers PMP and A / D converters respectively corresponding to the plurality of coil elements 106 ′ are provided in the same manner as the cover member 104 of the RF coil device 100 described above. 212, a P / S converter 214, and the like are arranged.

  In FIG. 23, the control circuit (108) and the like in each cover member 104, 104 'is omitted because it is complicated, but in reality, it is arranged in the same manner as in the first embodiment. For the same reason, the power reception unit 220, the ID transmission unit 222, the gate signal reception unit 224, and the antennas 206c and 206d of the coil-side wireless communication device are omitted, but actually, the arrangement is the same as in the first embodiment. Is done. For the same reason, the power supply unit 320, the ID reception unit 322, the gate signal transmission unit 324, and the antennas 306c and 306d of the control-side wireless communication apparatus 300 are omitted, but actually, as in the first embodiment. Be placed.

  Hereinafter, the flow of processing of the MR signal detected in the main scan will be described. Here, for simplification of explanation, it is assumed that only two coil elements 106, 106 'shown in the figure are selected for receiving MR signals in each RF coil device 100, 100'.

  MR signals emitted from the chest of the subject P are detected by the coil elements 106 in the cover member 104 of the RF coil device 100, amplified by the preamplifier PMP, input to the A / D converter 212, As in the first embodiment, the P / S converter 214 converts the signal into a serial signal. This serial signal is a digital signal and includes two MR signals detected by the two coil elements 106.

  The MR signal emitted from the waist of the subject P is detected by each coil element 106 ′ in the cover member 104 ′ of the RF coil device 100 ′, then amplified by the preamplifier PMP, and input to the A / D converter 212. After that, it is converted into a serial signal in the P / S converter 214 as in the first embodiment. This serial signal is a digital signal and includes two MR signals respectively detected by the two coil elements 106 '.

  Thereafter, the serial signal on the RF coil device 100 side is wirelessly transmitted from the coil-side wireless communication device on the right side of FIG. 23 to the control-side wireless communication device 300 as in the first embodiment. Thereafter, the data receiving unit 316 of the control-side radio communication apparatus 300 on the right side of FIG. 23 extracts the original digital MR signal from the received MR signal for radio transmission, and sends the extracted MR signal to the signal synthesis unit 580. input.

  At the same time, the serial signal on the RF coil device 100 ′ is similarly wirelessly transmitted from the coil side wireless communication device on the left side of FIG. 23 to the control side wireless communication device 300. Thereafter, the data receiving unit 316 of the control-side radio communication apparatus 300 on the left side in FIG. 23 extracts the original digital MR signal from the received MR signal for radio transmission, and sends the extracted MR signal to the signal synthesis unit 580. input.

  The signal synthesis unit 580 synthesizes two serial signals respectively input from the data reception units 316 of both control-side wireless communication devices 300 into one serial signal. That is, two serial signals respectively received by the two wireless communication paths on the RF coil device 100 side and the RF coil device 100 ′ side are combined into one serial signal. By combining, for example, the signal length is doubled. The synthesized serial signal includes MR signals received by the four coil elements 106 and 106 '. The signal synthesis unit 580 inputs the synthesized serial signal to the frequency down conversion unit 410 of the RF receiver 48.

  The frequency down-conversion unit 410 extracts signals corresponding to the MR signals of the four coil elements 106 and 106 'from the combined serial signal. The frequency down-conversion unit 410 performs the same frequency conversion on the MR signals received by the four coil elements 106 and 106 ′, and inputs the MR signals whose frequencies are lowered to the signal processing unit 412. . The following processing is the same as in the first embodiment.

  In the sixth embodiment having the above configuration, the following effects are obtained in addition to the same effects as those of the first to fifth embodiments. That is, the number of cables for the RF receiver 48 is reduced, and inspection, maintenance, and repair (part replacement) are facilitated. The reason will be described below.

  The MRI apparatus is usually shipped in a disassembled state for each unit, and operations such as assembly and installation adjustment are performed at the installation location. And it is often shipped as a bed apparatus (bed unit) in a state where the support table 31 and the top plate 34 are integrated. The number of connection cables between the RF coil device mounted on the subject P and the control side (RF receiver 48) of the MRI apparatus is increased due to the increase in the number of channels.

  For example, in a conventional MRI apparatus that does not wirelessly transmit MR signals via an induced electric field, eight connection ports for connecting an RF coil apparatus are provided on the top plate or a support base. Consider a case where 16 channel signal lines can be connected. In this case, at the time of assembly, for example, 16 × 8 = 128 signal lines are cable-connected between the bed apparatus side and the RF receiver side.

  However, in the configuration of the sixth embodiment, the number of signal lines on the support base 31 side can be reduced to one by the signal synthesis unit 580 as a minimum case. For this reason, the signal line connection work between the support base 31 side and the RF receiver 48 in the gantry 21 is facilitated. Accordingly, inspection, maintenance and repair (part replacement) are facilitated.

  Further, recent couch devices are provided with casters and are configured to be dockable to the gantry 21 in the imaging room. This is used for the purpose of transporting the patient to the imaging room on a top board in a separate room. If this embodiment is applied to such a dockable bed apparatus, since the number of signal lines coming out from the bed apparatus side is small, docking work immediately before imaging becomes easy, and work time can be shortened.

  In the sixth embodiment, an example in which a total of four MR signals digitized are combined into one serial signal has been described. The embodiment of the present invention is not limited to such an aspect. If the number of signal lines can be greatly reduced, the same effect as in the sixth embodiment can be obtained. When there are a large number of MR signals detected by a large number of coil elements 106 and 106 ′, all these MR signals are combined into one serial signal by the signal combining unit 580 and input to the RF receiver 48. Communication time is also required by the length of the signal length.

  Therefore, it is desirable to reduce the number of signal lines to such an extent that transmission of the MR signal to the RF receiver 48 is completed within an allowable communication time. For example, signal synthesizers 580 that synthesize a plurality of digital MR signals into one serial signal may be provided as many as the number of signal lines of MR signals connected to the RF receiver 48. Then, each signal line from the signal synthesizer 580 may be connected to the RF receiver 48.

  From the viewpoint of the communication time, as described in steps S4 and S5 of FIG. 7 of the first embodiment, only the MR signal detected by the coil element 106 selected for reception is controlled by the MRI apparatus 20B. It is desirable that the wireless transmission be performed on the side. This is because the data transmission amount of the MR signal can be minimized.

Hereinafter, the correspondence between the terms of the claims and the embodiments will be described. In addition, the correspondence shown below is one interpretation shown for reference, and does not limit the present invention.
The coil side wireless communication devices 200A to 200E are examples of the first wireless communication unit and the wireless communication unit recited in the claims.
The control-side wireless communication device 300 is an example of a second wireless communication unit and a signal acquisition unit described in the claims.

Fixing mechanism 500A-500E is an example of the support part of a claim. That is, support by a supporting unit includes the following two technical meanings.
First, as in the first to third embodiments and the fixing mechanisms 500A to 500C and 500E of the fifth embodiment, the coil-side wireless communication devices 200A to 200C and 200E are securely mounted on the top plate 34. This is the case of fixing to.
Second, as in the fixing mechanism 500D of the fourth embodiment, the position of the coil-side wireless communication device 200D is kept or maintained by frictional force.

The coil element 106 is an example of a detection unit described in the claims.
The A / D converter 212 is an example of an A / D converter according to claims.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

20A, 20B MRI apparatus 21 Gantry 22 Static magnetic field magnet 24 Shim coil 26 Gradient magnetic field coil 28 Transmitting RF coil 29 Receiving RF coil 30 Bed apparatus 34 Top panel 100 RF coil apparatus 102 Cable 104 Cover member 200A to 200E Coil side wireless communication apparatus 206a to 206d, 306a to 306d Antenna 300 Control side wireless communication device 470 Rail 500A to 500E Fixing mechanism 502a, 502c Support member 510 Elastic member 524 Protrusion 526 Spring 538 Housing 540 Non-slip sheet 550 Suction part 552 Suction tube 554 Suction port 580 Signal synthesizer P Subject

Claims (20)

A magnetic resonance imaging apparatus that acquires the nuclear magnetic resonance signal from an RF coil apparatus that detects a nuclear magnetic resonance signal emitted from a subject,
A first wireless communication unit that acquires the nuclear magnetic resonance signal detected by the RF coil device and wirelessly transmits the digitized nuclear magnetic resonance signal via an induced electric field;
A second wireless communication unit that receives the nuclear magnetic resonance signal wirelessly transmitted from the first wireless communication unit via the induced electric field;
An image reconstruction unit that reconstructs image data of the subject based on the nuclear magnetic resonance signal received by the second wireless communication unit;
The first wireless communication unit is connected to the second wireless communication unit such that an interval between the first wireless communication unit and the second wireless communication unit is an interval at which wireless transmission via the induction electric field is possible. A magnetic resonance imaging apparatus comprising: a support portion that is detachably supported, and a top plate on which the subject is placed. The magnetic resonance imaging apparatus according to claim 1.
The second wireless communication unit is embedded in the top board,
The support unit includes a support member that fits the first wireless communication unit when the first wireless communication unit slides on a surface of the top plate on which the subject is placed. Magnetic resonance imaging apparatus. The magnetic resonance imaging apparatus according to claim 2.
The wireless communication device further includes a notification unit that notifies that wireless communication is enabled when wireless communication via the induction electric field is enabled between the first wireless communication unit and the second wireless communication unit. A magnetic resonance imaging apparatus. The magnetic resonance imaging apparatus according to claim 3.
The magnetic resonance imaging apparatus, wherein the notification unit notifies by light emission that wireless communication is possible. The magnetic resonance imaging apparatus according to claim 4.
The first wireless communication unit and the second wireless communication unit have a plurality of wireless communication paths, and perform wireless transmission of the plurality of digitized nuclear magnetic resonance signals via the induction electric field. Configured to run on each route,
A magnetic resonance imaging apparatus, further comprising: a signal synthesis unit that synthesizes a plurality of the nuclear magnetic resonance signals respectively received by the second radio communication unit through the plurality of radio communication paths into one signal. The magnetic resonance imaging apparatus according to claim 1.
The support unit includes an anti-slip member that is located on a surface of the top plate on which the subject is placed and that exerts a frictional force on the housing of the first wireless communication unit,
The magnetic resonance imaging apparatus, wherein the second wireless communication unit is embedded in the top plate immediately below the anti-slip member. The magnetic resonance imaging apparatus according to claim 6.
The magnetic resonance imaging apparatus, wherein the first wireless communication unit includes a rechargeable battery that supplies power to the RF coil device. The magnetic resonance imaging apparatus according to claim 1.
The support section is fixed by sucking the first wireless communication section. A magnetic resonance imaging apparatus, wherein: The magnetic resonance imaging apparatus according to claim 8.
The support unit automatically starts suction of the first wireless communication unit when the wireless communication strength between the first wireless communication unit and the second wireless communication unit becomes a predetermined value or more. A magnetic resonance imaging apparatus. The magnetic resonance imaging apparatus according to claim 9.
A support table for supporting the top board; and a top board drive device for sliding the top board on the support board,
The magnetic resonance imaging apparatus, wherein the support unit automatically stops the suction of the first wireless communication unit when the top plate returns to a predetermined position on the support base. The magnetic resonance imaging apparatus according to claim 10.
The first wireless communication unit and the second wireless communication unit have a plurality of wireless communication paths, and perform wireless transmission of the plurality of digitized nuclear magnetic resonance signals via the induction electric field. Configured to run on each route,
A magnetic resonance imaging apparatus, further comprising: a signal synthesis unit that synthesizes a plurality of the nuclear magnetic resonance signals respectively received by the second radio communication unit through the plurality of radio communication paths into one signal. The magnetic resonance imaging apparatus according to claim 1.
The wireless communication device further includes a notification unit that notifies that wireless communication is enabled when wireless communication via the induction electric field is enabled between the first wireless communication unit and the second wireless communication unit. A magnetic resonance imaging apparatus. The magnetic resonance imaging apparatus according to claim 12,
The magnetic resonance imaging apparatus, wherein the notification unit notifies by light emission that wireless communication is possible. The magnetic resonance imaging apparatus according to claim 1.
The first wireless communication unit and the second wireless communication unit have a plurality of wireless communication paths, and perform wireless transmission of the plurality of digitized nuclear magnetic resonance signals via the induction electric field. Configured to run on each route,
A magnetic resonance imaging apparatus, further comprising: a signal synthesis unit that synthesizes a plurality of the nuclear magnetic resonance signals respectively received by the second radio communication unit through the plurality of radio communication paths into one signal. A bed apparatus that includes a top plate on which an object is placed and receives a nuclear magnetic resonance signal detected by an RF coil apparatus when performing magnetic resonance imaging;
The top plate is
A signal acquisition unit that receives the digitized nuclear magnetic resonance signal wirelessly transmitted from the wireless communication unit of the RF coil device via the induced electric field via the induced electric field;
A support unit that removably supports the wireless communication unit with respect to the signal acquisition unit such that an interval between the wireless communication unit and the signal acquisition unit is an interval that enables wireless transmission via the induction electric field. A bed apparatus comprising: and. The bed apparatus according to claim 15,
A support base for slidably supporting the top plate;
The bed apparatus further comprising: a caster provided on a bottom surface of the support table. The bed apparatus according to claim 15,
The support portion has an anti-slip member that is located on a surface of the top plate on which the subject is placed and works a frictional force with respect to a housing of the wireless communication unit,
The signal acquisition unit is embedded in the top plate directly below the anti-slip member. The bed apparatus according to claim 15,
The bed device is characterized in that the support portion is fixed by sucking the wireless communication portion. A detection unit for detecting a nuclear magnetic resonance signal emitted from the subject;
An A / D converter for digitizing the nuclear magnetic resonance signal;
When the magnetic resonance imaging apparatus is supported detachably with respect to the support part of the magnetic resonance imaging apparatus and is supported with respect to the support part, the digitized nuclear magnetic resonance signal is converted into the magnetic resonance via an induced electric field. An RF coil device comprising: a wireless communication unit that wirelessly transmits to an imaging device. The RF coil device according to claim 19, wherein
An RF coil device further comprising: a preamplifier that amplifies the nuclear magnetic resonance signal output from the detection unit and transmits the amplified signal to the A / D conversion unit.

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