Reception coil unit and medical image diagnostic system

Abstract

To provide a reception coil unit and a medical image diagnostic system capable of reducing a burden of imaging staff.SOLUTION: A reception coil unit includes: a band member; a first connection tool and a second connection tool provided in both ends of the band member, for connecting the band member to a table; a reception coil including a plurality of coil elements that receive a nuclear magnetic-resonance signal of a subject; and a hook member that is arranged in the reception coil and holds the band member in a manner that the reception coil is slidable along the band member.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a receiving coil unit and a medical image diagnostic system, and to a technique for reducing the burden on imaging staff. [Background technology]

[0002] When imaging a subject using a magnetic resonance imaging (MRI) device, the subject is placed in the imaging space of a gantry together with the table of a bed device. At this time, a receiving coil unit such as an RF (Radio Frequency) coil that receives nuclear magnetic resonance (NMR) signals is attached to the subject to obtain an image of the subject's imaging region (e.g., chest or abdomen).

[0003] Patent Document 1 discloses a technique for fixing a receiving coil unit to a subject. According to Patent Document 1, a receiving coil is attached to a region to be imaged, and then the receiving coil unit and the subject are fixed to a table by a fixing belt. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-92935 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, there has been a demand for technology to improve the workload (workflow) of imaging staff when attaching and fixing a receiving coil unit to a subject. In the technology of Patent Document 1, the receiving coil unit and the fixing belt (and further the subject and the abdominal coil) are separated, so two work processes are required: attaching the receiving coil unit and fixing it to the table with the fixing belt. This poses a problem of increasing the workload of imaging staff.

[0006] The present invention has been made in view of the above circumstances, and has an object to provide a receiving coil unit and a medical image diagnostic system that can reduce the burden on imaging staff. [Means for solving the problem]

[0007] The receiving coil unit of the first embodiment comprises a band member, a first connector and a second connector provided at both ends of the band member to connect the band member to a table, a receiving coil including a plurality of coil elements that receive nuclear magnetic resonance signals of a subject, and a hook member arranged on the receiving coil that holds the band member so that the receiving coil can slide along the band member.

[0008] The receiver coil unit of the second aspect is the same as that of the first aspect, except that the receiver coil does not have hook members on both ends, but has weight members on both ends.

[0009] The receiving coil unit of the third aspect is the receiving coil unit of the first aspect, in which the receiving coil includes a plurality of coil elements and a plurality of plate-shaped members that support the plurality of coil elements and are arranged at intervals, the plurality of plate-shaped members are configured to be foldable, and the hook member is arranged other than the plurality of plate-shaped members.

[0010] A fourth aspect of the receiver coil unit is the receiver coil unit of any one of the first to third aspects, wherein the receiver coil includes a flexible coil cover that covers the periphery of the plurality of coil elements.

[0011] The receiver coil unit of the fifth aspect is the receiver coil unit of the first aspect, wherein the receiver coil includes a plurality of coil elements and a rigid body portion that holds the plurality of coil elements.

[0012] A receiver coil unit of a sixth aspect is based on any one of the first to fifth aspects, wherein the first connector includes a length adjustment mechanism for the band member and a tightening mechanism.

[0013] The receiving coil unit of the seventh aspect is any of the first to sixth aspects, in which the first connecting device includes a length measuring sensor for measuring the length of the band member and / or a connection confirmation sensor for confirming whether the first connecting device is connected or not, and a transmission line for transmitting a detection signal from the length measuring sensor and / or connection confirmation sensor to the receiving coil.

[0014] A medical image diagnostic system of an eighth aspect includes a receiving coil unit of any one of the first to seventh aspects, a table having a movable top plate for placing a subject on it, and a magnetic resonance imaging device having a processor that processes nuclear magnetic resonance signals received by the receiving coil unit.

[0015] A ninth aspect of the medical image diagnostic system is the eighth aspect, wherein the movable top plate includes a moving rail along the longitudinal direction and to which the second connector is slidably connected.

[0016] A medical image diagnostic system according to a tenth aspect is the medical image diagnostic system according to the eighth or ninth aspect, wherein the table includes a retraction rail for retracting the receiving coil unit.

[0017] In a medical image diagnostic system according to an eleventh aspect, in any one of the eighth to tenth aspects, the receiving coil unit includes a coil connector, and the table includes a storage space for storing the coil connector.

[0018] A medical image diagnostic system of a twelfth aspect includes a receiving coil unit of any one of the first to sixth aspects, a length measuring sensor for measuring the length of a band member provided on a first connecting tool and a connection confirmation sensor for confirming whether the first connecting tool is connected or not, a transmission line for transmitting detection signals from the length measuring sensor and the connection confirmation sensor to a receiving coil, and a magnetic resonance imaging device including a processor for processing nuclear magnetic resonance signals received by the receiving coil unit and an input accepting device, wherein the processor determines a SAR limit value based on the detection signal from the length measuring sensor and displays the SAR limit value on the input accepting device, and the input accepting device accepts changes to the imaging parameters. [Effects of the Invention]

[0019] According to the present invention, it is possible to reduce the burden on the imaging staff of attaching the receiving coil unit. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view showing the appearance of a medical image diagnostic system according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the internal configuration of an MRI apparatus. [Figure 3] FIG. 3 is an exploded perspective view schematically showing the configuration of the receiving coil of the first embodiment. [Figure 4] FIG. 4 is a top view of the receiver coil unit of the first embodiment. [Figure 5] FIG. 5 is a top view of a modified example of the receiver coil unit of the first embodiment. [Figure 6] FIG. 6 is a diagram for explaining the procedure for attaching the receiving coil unit of FIG. 5 to a subject. [Figure 7] FIG. 7 is a diagram for explaining a modified example of the receiver coil unit of the first embodiment. [Figure 8] FIG. 8 is an exploded perspective view showing a schematic configuration of the receiving coil of the second embodiment. [Figure 9] FIG. 9 is a diagram for explaining the receiving coil unit of the second embodiment. [Figure 10] FIG. 10 is a diagram for explaining a modified example of the receiver coil unit of the second embodiment. [Figure 11] FIG. 11 is a diagram for explaining the procedure for attaching the receiving coil unit of FIG. 10 to a subject. [Figure 12] FIG. 12 is a diagram for explaining a modified example of the receiver coil unit of the second embodiment. [Figure 13] FIG. 13 is a diagram for explaining the receiving coil unit of the second embodiment. [Figure 14] FIG. 14 is a diagram for explaining a state in which the receiving coil unit of the embodiment is used. [Figure 15] FIG. 15 is a diagram for explaining another use state of the receiver coil unit of the embodiment. [Figure 16] FIG. 16 is a diagram for explaining another use state of the receiver coil unit of the embodiment. [Figure 17] FIG. 17 is a diagram for explaining another use state of the receiver coil unit of the embodiment. [Figure 18] FIG. 18 is a flowchart showing the procedure for changing imaging parameters using the receiving coil unit shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following description and accompanying drawings, identical components are designated by the same reference numerals, and duplicate explanations will be omitted. In addition, when multiple components are listed in the following embodiments, it can be interpreted that at least one of the multiple components is included.

[0022] As shown in FIG. 1, a medical image diagnostic system 10 according to the embodiment is a magnetic resonance imaging apparatus (hereinafter referred to as an MRI apparatus) 20, and includes a receiving coil unit 50.

[0023] [MRI device] The MRI apparatus 20 is installed in an examination room of an imaging diagnostic facility. In the examination room, a subject is placed on a movable top plate 34 of a table 32 of a bed apparatus 30. Thereafter, the movable top plate 34 moves, thereby transporting the subject toward a static magnetic field generating magnet 102 of the MRI apparatus 20.

[0024] The MRI apparatus 20 has a static magnetic field generating magnet 102. The static magnetic field generating magnet 102 has a cylindrical shape and has an upper imaging space 24 at the center of the cylindrical shape, and a table 32 moves into this imaging space 24. Gantry monitors 26 are installed on both the left and right sides of the static magnetic field generating magnet 102. The gantry monitors 26 also function as operation panels.

[0025] The three-dimensional coordinate system shown in FIG. 1 shows an example of the definition of directions in the MRI apparatus 20. The X-axis, Y-axis, and Z-axis of the three-dimensional coordinate system are an example and are not limited to this. For ease of understanding in the following description, the X-axis, Y-axis, and Z-axis in the MRI apparatus 20 are defined in the same direction in all figures. As an example of the three-dimensional coordinate system, the Z-axis direction is the static magnetic field direction, which is the front-back direction. The Y-axis direction is the up-down direction of the subject. The X-axis direction is the left-right direction of the subject.

[0026] FIG. 2 is a schematic diagram showing the internal configuration of the MRI apparatus 20. As shown in FIG.

[0027] As shown in FIGS. 1 and 2, the MRI apparatus 20 includes a static magnetic field generating magnet 102, a gradient magnetic field coil 104, and a transmission coil .

[0028] The static magnetic field generating magnet 102 generates a uniform static magnetic field in the imaging space 24 in which the subject 100 is placed. The gradient magnetic field coil 104 generates a gradient magnetic field in the imaging space 24. The transmission coil 106 generates a high-frequency magnetic field in the imaging space 24 to generate nuclear magnetic resonance signals (NMR (Nuclear Magnetic Resonance) signals) (hereinafter referred to as NMR signals) in the nuclei of atoms constituting the tissue of the subject 100.

[0029] The subject 100 is placed on a movable top plate 34, and a receiving coil unit 50 is attached to the chest and abdomen of the subject 100. By moving the table 32 on which the subject 100 is placed into the imaging space 24, the examination region (image target region) of the subject 100 is positioned at the center of the static magnetic field of the imaging space 24. The receiving coil unit 50 is attached to the subject 100 and detects NMR signals generated from the subject 100.

[0030] The sequencer 108 sends commands to the radio frequency transmitter 110 and the gradient magnetic field power supply 112 in accordance with an imaging sequence (pulse sequence), and appropriately amplified signals are sent to the transmission coil 106 and the gradient magnetic field coil 104, respectively.

[0031] The signal sent to the transmitting coil 106 is applied to the subject 100 as a pulsed radio frequency magnetic field (RF pulse) via the transmitting coil 106. The NMR signal generated from the subject 100 is detected by the coil elements 52 of the receiving coil unit 50, and is detected by the receiver 114.

[0032] The gradient magnetic field coil 104 is composed of gradient magnetic field coils in three directions, X, Y, and Z, and generates gradient magnetic fields in response to signals from a gradient magnetic field power supply 112 .

[0033] The nuclear magnetic resonance frequency (detection reference frequency f0) used as the detection reference in the receiver 114 is set by the sequencer 108. The sequencer 108 controls each component so that it operates at pre-programmed timing and intensity. Among the programs, the one that particularly describes the timing and intensity of the RF pulse, gradient magnetic field, and signal reception is called a pulse sequence.

[0034] There are various known pulse sequences depending on the purpose, but a detailed description thereof will be omitted here.

[0035] The control unit 116 controls the operation of the MRI apparatus 20 via the sequencer 108, receives the signal detected by the receiver 114, and performs various signal processing such as image reconstruction. The receiver 114 performs quadrature phase detection on the received signal (NMR signal), which is an analog wave, using a set detection reference frequency f0, performs AD (analog-to-digital) conversion, and then transmits the data to the control unit 116. This data is also called the received signal or measurement data.

[0036] The control unit 116 receives various instruction inputs from the operation unit 118 and performs overall control of each unit of the MRI apparatus 20. The control unit 116 also performs processing such as converting the received signals in the spatial frequency domain received via the sequencer 108 into an image in real space by inverse Fourier transform, thereby generating an MRI image.

[0037] The control unit 116 is realized by a general-purpose computer such as a personal computer or a microcomputer, etc. The control unit 116 includes a processor (for example, a CPU (Central Processing Unit)), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface, etc.

[0038] In the control unit 116, various programs such as a control program stored in the ROM are loaded into the RAM, and the programs loaded into the RAM are executed by the CPU, thereby realizing the functions of each unit of the MRI apparatus 20 and executing various arithmetic processing and control processing via the input / output interface.

[0039] The operation unit 118 includes a mouse, a keyboard, and the gantry monitor 26. The operation unit 118 functions as part of a GUI (Graphical User Interface) that accepts input from the imaging staff. The operation unit 118 is an example of an input accepting device of the present invention.

[0040] The imaging staff inputs, through the operation unit 118, the start and stop (including temporary stop) of the MRI apparatus 20, the selection of a pulse sequence, imaging conditions, processing conditions, and the like.

[0041] [Receiver coil unit of the first embodiment] A receiver coil unit 50 according to the first embodiment will be described. The receiver coil unit 50 has a blanket-like shape and is thinner, lighter, and more flexible than an integrally molded unit. This receiver coil unit 50 can be deformed to fit the physique of the subject 100, enabling imaging of various examination regions. The receiver coil unit 50 is an example of a receiver coil unit according to the present invention.

[0042] 3 is an exploded perspective view schematically showing the configuration of the receiving coil 51 that constitutes the receiving coil unit 50. As shown in FIG. 3, the receiving coil 51 includes a plurality of coil elements 52, a plurality of signal processing circuits 54 that are electrical components connected to the plurality of coil elements 52, respectively, and a coil cover 56.

[0043] The coil elements 52 function as detectors (sensors) that receive NMR signals. For example, the coil elements 52 are made of conductors and have a ring shape with a diameter of approximately 10 cm to 15 cm. The coil elements 52 are arranged two-dimensionally inside a coil cover 56. The receiving coil unit 50 of this example has 24 coil elements 52, which are arranged in an array to prevent electromagnetic interference with each other, thereby achieving multi-channel operation. The number and arrangement of the coil elements 52 are not limited to the example of FIG. 3. The coil elements 52 may be configured to be deformable to fit the physique of the subject 100. The coil cover 56 is an example of a coil cover of the present invention.

[0044] The signal processing circuit 54 is composed of an impedance matching circuit, an amplifier circuit, etc., and may be packaged, for example, as an electrical circuit including multiple circuit elements in a cubic or rectangular parallelepiped housing. The signal processing circuit 54 further includes a magnetic coupling prevention circuit for preventing intrusion of energy irradiated from the transmitting coil 106 and eliminating coupling between the coil element 52 and the transmitting coil 106. The magnetic coupling prevention circuit is composed of a capacitor, a diode, and an inductor. The inductor and diode are connected in series to form a series circuit. This series circuit is connected in parallel with the capacitor. The diode is connected to a magnetic coupling prevention circuit driver. When the diode is ON, the parallel resonant circuit composed of the capacitor, inductor, and diode can align its resonant frequency with the resonant frequency of the transmitting coil 106, which is tuned to the same frequency as the magnetic resonance frequency. This prevents magnetic coupling between the transmitting coil 106 and the receiving coil unit 50.

[0045] The coil cover 56 is a cover that constitutes a housing that covers the periphery of the multiple coil elements 52 and the signal processing circuit 54. Electrical components including the multiple coil elements 52 and multiple signal processing circuits 54 are housed inside the coil cover 56, constituting a blanket-shaped receiving coil 51. The multiple coil elements 52 and multiple signal processing circuits 54 may be housed inside the coil cover 56 in a state where they are fixed on a film (not shown). The film is a support member that fixes the positional relationship between the coil elements 52 and the signal processing circuit 54 and prevents misalignment.

[0046] The coil cover 56 is formed into a bag-like shape by sewing or gluing together the edges of a sheet-like material cut into one piece. In this example, the bag-like coil cover 56 is formed by sewing or gluing together a first sheet body 56A and a second sheet body 56B. The material of the coil cover 56 may be a urethane-based resin such as polyurethane, or a polyamide synthetic resin such as nylon. The surface of the first sheet body 56A exposed to the outside constitutes the outer surface that does not contact the subject (hereinafter also referred to as the non-contact outer surface). The surface of the second sheet body 56B exposed to the outside constitutes the outer surface that contacts the subject (hereinafter also referred to as the contact outer surface). A signal cable (not shown) is connected to the coil cover 56. This signal cable is a unit that combines multi-channel cables for obtaining signals from each of the multiple coil elements 52 and is electrically connected to multiple signal processing circuits 54.

[0047] 4 is a top view of the receiving coil unit 50 including the receiving coil 51, as viewed from the first sheet body 56A. The receiving coil unit 50 includes the receiving coil 51, a guide band 60, a band hook 62, a handle 64, a buckle 66, and a rail runner 68.

[0048] As shown in FIG. 4, the guide bands 60 are string-like members having a length that exceeds both opposing ends of the receive coil 51. In this example, each guide band 60 extends along the X-axis direction. Two guide bands 60 are arranged side by side along the Z-axis direction at a certain distance. The number of guide bands 60 is not limited to two, and may be one or more than two. The guide bands 60 may be stretchable. Having stretchability allows the receive coil 51 and the subject 100 to come into contact with each other even for subjects with different body shapes. The guide bands 60 are an example of a band member of the present invention.

[0049] A handle 64 is provided at one end of each of the two guide bands 60. One handle 64 is applied as a common member to the two guide bands 60. The handle 64 is a member that is gripped by the imaging staff when fixing the guide band 60 to the movable top plate 34. There are no particular limitations on the size, shape, and material of the handle 64, as long as it is easy for the imaging staff to grip.

[0050] Two buckles 66 are provided on the handle 64 on the side opposite to the side on which the guide band 60 is provided. The two buckles 66 are members for one-touch connecting (fixing) the guide band 60 to the movable top plate 34. The buckles 66 and the movable top plate 34 are connected, for example, by snap-fitting, as will be described later. The handle 64 and the buckles 66 are an example of a first connecting tool of the present invention.

[0051] A rail runner 68 is provided on each of the other ends of the two guide bands 60. The rail runner 68 is a member that is movably attached to the movable top plate 34, as will be described later. The rail runner 68 is an example of a second connector of the present invention.

[0052] A band hook 62 is attached to the coil cover 56. The band hook 62 is a member through which the guide band 60 is inserted and held. In this example, the band hook 62 is composed of multiple strip-shaped members extending in the Z-axis direction. The multiple strip-shaped members are arranged at intervals along the X-axis direction. The guide band 60 is slidably inserted through the band hook 62. The receiving coil 51, the guide band 60, and the band hook 62 are integrated to form the receiving coil unit 50. The receiving coil 51 can move (slide) in the X-axis direction along the guide band 60 thanks to the band hook 62. Note that because the band hook 62 is composed of a strip-shaped member, the guide band 60 has a configuration in which portions covered by the strip-shaped members and portions exposed to the outside alternate, as shown in FIG. 4 . The band hook 62 is preferably made of a flexible material, similar to the coil cover 56. Although an example has been shown in which the band hook 62 is configured from a plurality of strip-shaped members, the configuration of the band hook 62 is not particularly limited as long as the guide band 60 can be inserted therethrough and the receiving coil 51 can be moved along the guide band 60. The band hook 62 may be tubular (or cylindrical) in shape with openings formed at both ends and a space communicating with the openings. If the band hook 62 has a tubular (or cylindrical) shape, the guide band 60 can be slidably inserted therethrough. The band hook 62 is an example of a hook member of the present invention.

[0053] Fig. 5 is a top view of a receiver coil unit 50A which is a modified example of the receiver coil unit 50. In Fig. 5, parts common to the above-described embodiment are given the same reference numerals, and description thereof will be omitted.

[0054] 5 is provided with a stringing rod 70 between the receiving coil 51 and the rail runner 68. The rail runner 68 is attached to the stringing rod 70.

[0055] The stringing rod 70 has a hollow structure with an internal space 70A and two openings 70B for passing the guide band 60 through. In this example, one guide band 60 is arranged so that it passes through the space 70A from the two openings 70B of the stringing rod 70. The guide bands 60 are arranged in an overall U-shaped pattern. The size, shape, and material of the stringing rod 70 are not particularly limited as long as they can pass through the guide band 60. The stringing rod 70 is preferably made of a rigid member. By passing one guide band 60 through the stringing rod 70, the stringing rod 70 can determine the position of the guide band 60 on the side of the rail runner 68. The stringing rod 70 can function as a handle that can be held by the imaging staff. By holding the stringing rod 70, the imaging staff can easily fit the rail runner 68 into the moving rail of the movable top plate 34.

[0056] 6 is a diagram illustrating the procedure for attaching the receiving coil unit 50A to the subject 100, as viewed from the rear to the front along the Z-axis direction. 6-1 in FIG. 6 is a diagram illustrating the state before the receiving coil unit 50A is fixed to the movable top plate 34 with the buckles 66, and 6-2 in FIG. 6 is a diagram illustrating the state after the receiving coil unit 50A has been attached to the subject 100 and fixed to the movable top plate 34 with the buckles 66.

[0057] As shown in FIG. 6A, the subject 100 is placed on the movable top 34. The back coil 35 is disposed on the side of the movable top 34 on which the subject 100 is placed. As shown in the enlarged view, the rail runner 68 is fitted into the movable rail 36 of the movable top 34 and connected to the movable rail 36. The rail runner 68 is composed of a head 68A and a neck 68B. The head 68A is wider in the X-axis direction than the neck 68B. The movable rail 36 is composed of a substantially rectangular frame-shaped member 36A with a groove 36B formed on its upper side. The width of the head 68A is smaller than that of the frame-shaped member 36A but larger than that of the groove 36B. The width of the neck 68B is smaller than that of the groove 36B. This configuration allows the rail runner 68 to move back and forth along the Z-axis direction. On the other hand, the rail runner 68 has a so-called slip-out prevention structure, in which upward movement in the Y-axis direction is restricted by the movable rail 36. There are no particular limitations on the size, shape, and material of the rail runner 68, as long as it can move along the moving rail 36. The moving rail 36 is an example of the moving rail of the present invention.

[0058] The imaging staff holds the handle 64, winds the receiving coil 51 around the subject 100, and brings the receiving coil 51 into close contact with the observation region of the subject 100. At this time, in the receiving coil unit 50A of this example, the receiving coil 51 can be moved along the guide band 60 in the direction indicated by arrow A. The imaging staff can easily move the receiving coil 51 to the observation region of the subject 100.

[0059] Next, as shown in FIG. 6-2, the imaging staff member holds the handle 64 and inserts the buckle 66 into the fixed rail 38 provided on the movable top panel 34. This connects (fixes) the buckle 66 to the fixed rail 38. The buckle 66 is composed of a claw portion (protrusion) 66A and an elastic member 66B. The elastic force of the elastic member 66B allows the distance between the two claw portions 66A to be freely changed. The fixed rail 38 is composed of a substantially rectangular frame-shaped member 38A with a groove 38B formed on its upper side. When connecting (fixing) the buckle 66 to the fixed rail 38, applying force to the elastic member 66B reduces the distance between the two claw portions 66A. The claw portion 66A can pass downward through the groove 38B. Once the claw portion 66A passes through the groove 38B, the elastic force of the elastic member 66B returns the claw portion 66A to its initial position. As shown in FIG. 6-2, the two claws 66A engage with the frame-shaped member 38A, connecting (fixing) the buckle 66 to the fixed rail 38. To release the fixation, a force is applied to the elastic member 66B, thereby reducing the distance between the two claws 66A. The claws 66A can pass upward through the groove 38B, thereby releasing the fixation. The buckle 66 can be easily fixed to and released from the fixed rail 38. The size, shape, and material of the buckle 66 are not particularly limited as long as they can be fixed to and released from the fixed rail of the movable top plate 34.

[0060] 6, the operating staff can attach the receiving coil 51 to the imaging region of the subject 100 and fix the receiving coil unit 50A and the subject 100 to the table 32 in one operation, and the coil and the subject can be fixed in one operation.

[0061] Fig. 7 is a diagram for explaining a receiving coil unit 50B, which is a modified example of the receiving coil unit 50A. In Fig. 7, parts common to the receiving coil unit 50A described above are given the same reference numerals, and their description will be omitted. Fig. 7-1 is a top view of the receiving coil unit 50B, and Fig. 7-2 is a diagram showing the receiving coil unit 50B attached to the subject 100 and fixed to the movable top plate 34.

[0062] The receiving coil unit 50B shown in 7-1 of FIG. 7 differs from the receiving coil unit 50A in that it has weights 71 on both ends of the receiving coil 51 (the sides where the handle 64 and rail runner 68 are provided). The receiving coil unit 50B does not have band hooks 62 at the positions where the weights 71 are arranged. The band hooks 62 extend from the center of the receiving coil 51 toward both ends of the receiving coil 51, but do not reach both ends. The band hooks 62 in this example are tubular, and the guide band 60 is slidably inserted into the band hooks 62. The receiving coil 51 can move along the guide band 60.

[0063] As shown in 7-2 of FIG. 7, the receiving coil unit 50B is attached and fixed to the subject 100. The receiving coil 51 does not have band hooks 62 at either end. Compared to 6-2 of FIG. 6, both ends of the receiving coil 51 can be moved away from the guide band 60. Furthermore, the weight 71 exerts a force in the direction of gravity on both ends of the receiving coil 51. This allows the receiving coil 51 to approach the side (flank) of the subject 100, improving the image quality of the image acquired based on the signal from the receiving coil 51. The weight 71 is an example of a weight member of the present invention. The weight may be the coil element 52 or the signal processing circuit 54. It is sufficient that the area of the weight 71 in the figure is more susceptible to the force of gravity than other parts, causing it to hang down. The receiving coil units 50A and 50B are examples of receiving coil units of the present invention.

[0064] [Receiving coil unit of second embodiment] Next, a foldable receiver coil unit 50C will be described. FIG. 8 shows a receiver coil 51A that is applied to the receiver coil unit 50C. The configuration of the receiver coil 51A is different from that of the receiver coil 51 of the first embodiment. As shown in FIG. 8, the receiver coil 51A includes a plurality of coil elements 52 and a plurality of plate-shaped members 55 that are spaced apart. One coil element 52 is supported by two plate-shaped members 55. In this example, there are six plate-shaped members 55, and five coil elements 52 are supported by these six plate-shaped members 55. The plurality of coil elements 52 and the plurality of plate-shaped members 55 are housed in a coil cover 56. Each coil element 52 is deformable. The spacing between adjacent plate-shaped members 55 can be changed as the coil elements 52 are deformed.

[0065] FIG. 9 is a diagram for explaining the receiver coil unit of the second embodiment. 9-1 in FIG. 9 is a top view of the receiver coil unit 50C, and 9-2 in FIG. 9 is a diagram of the receiver coil unit 50C before it is attached to the subject 100, viewed from the rear side to the front side along the Z-axis direction. As shown in 9-1 in FIG. 9, band hooks 62 are provided on the receiver coil 51A. In this example, the band hooks 62 are provided in areas other than the plate-like members 55, i.e., in areas where no plate-like members 55 are provided (no-arrangement areas). However, the band hooks 62 are provided in three of the five no-arrangement areas. The guide band 60 is slidably inserted through the three band hooks 62.

[0066] As shown in 9-2 of FIG. 9, the receiving coil 51A includes a plurality of spaced apart plate-like members 55, and is configured to be foldable by changing the spacing between them. The guide band 60 has three band hooks 62 inserted therethrough. This configuration allows the receiving coil 51A to move along the guide band 60. In this example, the guide band 60 passes through the inside of the coil cover 56 at a position where it is inserted through the band hooks 62. The guide band 60 is exposed from the coil cover 56 at a position where it is not inserted through the band hooks 62.

[0067] The imaging staff can easily align the receiving coil 51 with the observation region of the subject 100 by moving the receiving coil 51A before connecting the buckle 66 to the movable top plate 34. By connecting (fixing) the buckle 66 to the movable top plate 34, the receiving coil unit 50A and the subject 100 can be fixed to the movable top plate 34 (table 32). In other words, the coil and the subject can be fixed in one operation.

[0068] Fig. 10 is a diagram for explaining a modified example of a foldable receiver coil unit 50C. In Fig. 10, parts common to the receiver coil unit 50C described above are given the same reference numerals, and description thereof will be omitted.

[0069] A receiver coil unit 50D shown in FIG. 10 differs from the receiver coil unit 50C in that a handle 72 is provided with an automatic winding reel 73, a stop lever 74, and a ratchet 75.

[0070] The handle 72 is composed of a first handle 72A to which the guide band 60 is connected and a second handle 72B to which the buckle 66 is attached. The first handle 72A has a hollow structure with an internal space and two automatic winding reels 73 are disposed. One end of the guide band 60 is connected to each of the two automatic winding reels 73. The automatic winding reels 73 may be, for example, a spring-type structure using a leaf spring. The guide band 60 is preferably made of a non-stretchable, flexible material. Therefore, it is preferable that the length of the guide band 60 itself does not change during normal use. Furthermore, in the initial state, the guide band 60 is wound around the automatic winding reel 73 by the force of the leaf spring, so the length of the guide band 60 is short. In this example, two automatic winding reels 73 are disposed, but only one automatic winding reel 73 may be disposed. However, providing two automatic winding reels 73 can prevent the guide band 60 from sliding on the subject 100. Friction between the guide band 60 and the subject 100 can be avoided.

[0071] A stop lever 74 is disposed between the two automatic winding reels 73. The stop lever 74 is a member that regulates the force of the automatic winding reel 73 in the winding direction. When the stop lever 74 is operated, the winding of the automatic winding reel 73 is regulated, and the length of the guide band 60 is determined. The imaging staff can use the automatic winding reel 73 and the stop lever 74 to adjust the length of the guide band 60 (the length of the guide band 60 exposed from the handle 72) to suit the physique of the subject 100, etc. The automatic winding reel 73 and the stop lever 74 are an example of a length adjustment mechanism of the present invention. Note that the receive coil 51A in FIG. 10 does not have a coil cover 56.

[0072] The handle 72 is provided with a ratchet 75. The ratchet 75 is composed of two pawls 75A and two gears 75B. The two pawls 75A are located at positions connecting the first handle 72A and the second handle 72B. The two pawls 75A are fixed by a pin (not shown) connecting their centers. The two pawls 75A can open and close using the pin as a fulcrum. The second handle 72B has a hollow structure with an internal space and is equipped with two linear rack-shaped gears 75B. The two gears 75B are arranged opposite each other. The two pawls 75A engage with the two gears 75B to determine the distance between the first handle 72A and the second handle 72B. In other words, the ratchet 75 can adjust the distance between the first handle 72A and the second handle 72B. The ratchet 75 is an example of a tightening mechanism of the present invention.

[0073] 11 is a diagram illustrating the procedure for attaching the receiving coil unit 50D to the subject 100, as viewed from the rear to the front along the Z-axis direction. 11-1 in FIG. 11 is a diagram illustrating the state before the receiving coil unit 50D is fixed to the movable top plate 34 with the buckles 66, and 11-2 in FIG. 11 is a diagram illustrating the state after the receiving coil unit 50D has been attached to the subject 100 and fixed to the movable top plate 34 with the buckles 66.

[0074] As shown in 11-1 of FIG. 11, the subject 100 is placed on the movable top plate 34. The rail runner 68 (not shown) of the receiving coil unit 50D is fitted into the movable rail 36 (not shown) of the movable top plate 34 and connected to the movable rail 36. The receiving coil unit 50D is prepared on the movable top plate 34. In this state, the length of the guide band 60 of the receiving coil unit 50D is at its shortest because it has been wound up by the automatic winding reel 73 (not shown).

[0075] As shown in 11-2 of FIG. 11, the imaging staff unwinds the guide band 60 from the automatic reel 73 according to the physique of the subject 100. The imaging staff operates the stop lever 74 to determine the length of the guide band 60. The imaging staff holds the handle 72 and moves the receiving coil 51A along the guide band 60 while winding it around the subject 100. The imaging staff brings the receiving coil 51A into close contact with the observation site of the subject 100. The imaging staff holds the handle 72 and inserts the buckle 66 into the fixing rail 38 provided on the movable top plate 34. This connects (fixes) the buckle 66 to the fixing rail 38. Furthermore, the imaging staff operates the ratchet 75 of the handle 72 to shorten the distance between the first handle 72A and the second handle 72B. This allows the guide band 60 to be further tightened, thereby achieving optimal fixation strength for fixing the coil and the subject. The handle 72 is equipped with an automatic reel 73, a stop lever 74, and a ratchet 75, so that it is possible to achieve optimal fixation strength for subjects 100 of any physique. Furthermore, the receiving coil 51A is equipped with plate-like members 55 on both ends, which function as weights. This allows the receiving coil 51A to approach the sides (flanks) of the subject 100, improving the image quality.

[0076] Fig. 12 is a diagram for explaining a modified example of the receiving coil unit 50D. In Fig. 12, parts common to the receiving coil unit 50D described above are assigned the same reference numerals, and their description will be omitted. Fig. 12 12-1 is a diagram showing the receiving coil unit 50E in a state before it is fixed to the movable top plate 34 with the buckles 66, and Fig. 12 12-2 is a diagram showing the receiving coil unit 50E attached to the subject 100 and fixed to the movable top plate 34 with the buckles 66.

[0077] A receiving coil unit 50E shown in FIG. 12 differs from the receiving coil unit 50D in that a handle 72 is provided with an attachment sensor 76, a length sensor 77, and a transmission line 78.

[0078] The attachment sensor 76 is a sensor that outputs a detection signal such as ON or High when the buckle 66 is inserted into the fixed rail 38, and outputs a detection signal such as OFF or Low when the buckle 66 is not inserted into the fixed rail 38. The attachment sensor 76 is not limited to a particular type as long as it can output a binary detection signal that can be distinguished depending on whether the buckle 66 is inserted into the fixed rail 38. The attachment sensor 76 is an example of a connection confirmation sensor of the present invention.

[0079] The length sensor 77 outputs a detection signal corresponding to, for example, the length of the guide band 60 unwound from the automatic winding reel 73. An example of the length sensor 77 is one that detects the rotation of the automatic winding reel 73 using an encoder or the like and converts this rotation into a payout length and outputs the result as a detection signal. The type of the length sensor 77 is not limited as long as it can output a detection signal corresponding to the length of the guide band 60. The length sensor 77 is an example of a length measuring sensor of the present invention.

[0080] Furthermore, a transmission line 78 is provided which is connected to the attachment sensor 76 and the length sensor 77. The transmission line 78 transmits detection signals from the attachment sensor 76 and the length sensor 77 to the receiving coil 51A. The transmission line 78 is an example of the transmission line of the present invention.

[0081] As shown in 12-1 of FIG. 12, the imaging staff pays out the guide band 60 from the automatic winding reel 73 according to the physique of the subject 100. The imaging staff operates the stop lever 74 to determine the length of the guide band 60. The length sensor 77 outputs a detection signal corresponding to the length of the paid-out guide band 60. The detection signal is stored in, for example, a memory.

[0082] As shown in 12-2 of FIG. 12, the imaging staff holds the handle 72 and moves the receiving coil 51A along the guide band 60 while winding it around the subject 100. The imaging staff brings the receiving coil 51A into close contact with the observation area of the subject 100. The imaging staff holds the handle 72 and inserts the buckle 66 into the fixed rail 38 provided on the movable top panel 34. When the buckle 66 is inserted into the fixed rail 38, the attachment sensor 76 outputs an ON detection signal.

[0083] For example, when the wearing sensor 76 outputs an ON detection signal, the detection signal from the wearing sensor 76 and the detection signal from the length sensor 77 are transmitted to the receiving coil 51A via the transmission line 78. This allows the detection signals (length information of the guide band 60 and fixation information of the buckle 66) to be transmitted to the MRI apparatus 20 via the receiving coil 51A.

[0084] In this embodiment, one coil element 52 is supported by two plate-like members 55, but this is not limiting. A structure in which two coil elements are arranged in an array and supported by two plate-like members 55 is also possible. This allows the number of coil elements 52 to be increased also in the axial direction of the plate-like member 55, thereby increasing sensitivity.

[0085] [Receiving coil unit of the third embodiment] Next, a description will be given of a receiver coil unit 50F having a certain radius of curvature according to the physique of the subject 100. Fig. 13 shows a receiver coil 51B applied to the receiver coil unit 50F. The configuration of the receiver coil 51B is different from that of the receiver coil 51 of the first embodiment and the receiver coil 51A of the second embodiment.

[0086] The receive coil 51B includes a main body 57 having a curved surface that is bent so as to fit the body shape of the subject 100, and a coil element 52 provided inside the main body 57. The main body 57 has enough rigidity to maintain its shape under normal use. The main body 57 is configured with a cutout hole 58 provided in a portion where the coil element 52 is not present. Providing this cutout hole 58 makes it possible to reduce the weight of the entire receive coil 51B. The main body 57 has a gently curved surface that is convex upward toward the subject 100, and therefore can be attached to the subject 100 (not shown) with good adhesion.

[0087] Three band hooks 62 are provided side by side in the X-axis direction on the upper surface side of the main body 57 of the receiving coil 51B. The guide band 60 is slidably inserted into the band hooks 62. This allows the receiving coil 51B to move along the guide band 60 in the X-axis direction.

[0088] A rail runner 68 is provided at one end of the guide band 60. A handle 64 and a buckle 66 are provided at the other end of the guide band 60.

[0089] The imaging staff fits the rail runner 68 into the moving rail 36 (not shown). The imaging staff moves the receive coil 51B along the guide band 60 to bring it into close contact with the subject 100, and then holds the handle 64 and connects the buckle 66 to the fixed rail 38 (not shown). This allows the imaging staff to fix the coil and the subject in a single operation.

[0090] [Usage state of the receiving coil unit of the embodiment] Next, a usage state of the receiving coil unit of the embodiment will be described.

[0091] 14 is a diagram for explaining the case where the receiving coil unit 50A is used, and is a top view of the subject 100 placed on the movable top board 34. The receiving coil unit 50A is attached to the abdomen of the subject 100 shown in FIG.

[0092] 14, a movable rail 36 is provided along the longitudinal direction (Z-axis direction) of the movable top plate 34. A rail runner 68 (not shown) is movably fitted into the movable rail 36. With this configuration, the receive coil unit 50A can move in the front-to-back direction (Z-axis direction) as shown by the arrow, that is, from the lower abdomen to the upper abdomen.

[0093] Fig. 15 is a diagram for explaining the case where the receive coil unit 50C is used. 15-1 in Fig. 15 is a top view of the subject 100 placed on the movable top plate 34. 15-2 in Fig. 15 is a view of the subject 100 placed on the movable top plate 34 as seen from the back side to the front side along the Z-axis direction.

[0094] As shown in 15-1 of FIG. 15, the subject 100 is placed on the movable top plate 34. The receiving coil unit 50D is placed on the movable top plate 34. One end of a receiving cable 59 is connected to the receiving coil 51A. A coil connector 61 is connected to the other end of the receiving cable 59. The coil connector 61 is connected to a connector 40 arranged on the movable top plate 34. The receiving coil unit 50D has a guide band 60 in a shortened state due to an automatic winding reel 73. A coil retraction rail 39 is provided on the table 32. The coil retraction rail 39 is a member for retracting the coil when the receiving coil unit 50C is not in use. The coil retraction rail 39 is an example of a retraction rail of the present invention.

[0095] 15-2, the receiving coil unit 50D is guided by the coil retraction rails 39 and can be moved to the rear side of the table 32. As a result, the receiving coil unit 50D is no longer on the movable top plate 34, and the imaging staff can perform other tasks without being hindered by the receiving coil unit 50D. The imaging staff can perform various tasks without any burden.

[0096] Fig. 16 is a diagram for explaining a case where the receiving coil unit 50D is used. The table 32 in Fig. 16 is different from the table 32 of 15-2 in Fig. 15. As shown in Fig. 16, the table 32 is provided with a space 41. The space 41 can accommodate the coil connector 61 when not in use. The table 32 can also serve as a storage space for the coil connector 61. The coil connector 61 is an example of a coil connector of the present invention. The space 41 is an example of an accommodation space of the present invention.

[0097] In the MRI apparatus 20, an RF signal is irradiated onto a subject wearing a receiving coil, and therefore heat may be generated in a part of the circuit of the receiving coil that is irradiated. To prevent damage to the receiving coil, it is preferable to be able to control the irradiated RF signal as needed and control the heat generation in the circuit. In this embodiment, one of the means for achieving this is a function (SAR management function) provided in the MRI apparatus 20 that suppresses the SAR (Specific Absorption Ratio), which is the absorption rate (specific absorption rate) of RF signals in the human body, to a predetermined threshold or less.

[0098] Fig. 17 is a diagram for explaining a case where SAR management is performed by using the receiving coil unit 50E. Fig. 18 is a flowchart showing the procedure for changing imaging parameters.

[0099] One of the causes of heat generation in the receive coil 51A is when the receive coil 51A approaches the inner wall 25 of the imaging space 24 of the MRI device 20. A transmit coil 106 that outputs high-power radio waves is arranged around the inner wall 25. If the receive coil 51A is located close to the inner wall 25, there is a concern that the receive coil 51A will receive high power and generate heat. To avoid this, it is effective to suppress the output of the transmit coil 106. However, it has been difficult to know how far the receive coil 51A is located from the inner wall 25.

[0100] In this example, SAR management is performed by the following receive coil unit 50E and the following procedure: As described above, the receive coil unit 50E includes, in the handle 72, the length sensor 77 that measures the length of the guide band 60 and the transmission line 78.

[0101] 18 , in guide band length detection (step S1), the length of the guide band 60 is detected from a detection signal from the length sensor 77. Specifically, the detection signal detected by the length sensor 77 (a detection signal corresponding to the length of the guide band 60) is transmitted from the transmission line 78 to the receiving coil 51A, and then transmitted from the receiving coil 51A to the control unit 116 of the MRI apparatus 20. The control unit 116 detects (acquires) the length of the guide band 60 from the detection signal detected by the length sensor 77.

[0102] Next, in determining the maximum SAR (step S2), the control unit 116 determines the maximum SAR from the length of the guide band 60.

[0103] There is a certain relationship between the length of the guide band 60 and the physique of the subject 100. When the guide band 60 is long, the size of the subject 100 is large, and when the guide band 60 is short, the size of the subject 100 is small. From the length of the guide band 60, the distance between the subject 100 and the inner wall 25 can be estimated. When the guide band 60 is long, it can be estimated that the distance between the subject 100 and the inner wall 25 is short, and when the guide band 60 is short, it can be estimated that the distance between the subject 100 and the inner wall 25 is long.

[0104] The control unit 116 stores in advance a data table shown in Table 1. Here, the data table associates the length of the guide band 60 with the SAR limit value. As shown in Table 1, when the length of the guide band 60 is 10-80 cm, the SAR limit value is 2.0 W / kg, when the length is 81-100 cm, the SAR limit value is 1.5 W / kg, and when the length is 101-130 cm, the SAR limit value is 1.0 W / kg. From these relationships between the length of the guide band 60 and the SAR limit value, it can be understood that the longer the guide band 60, the smaller the SAR limit value. As described above, the longer the guide band 60, the closer the subject 100 is to the inner wall 25, so the SAR limit value is set small for safety reasons. Note that the data table shown in Table 1 is an example of a combination of the length of the guide band 60 and the SAR limit value, and is not limited to this.

[0105] [Table 1]

[0106] The control unit 116 determines the SAR limit value based on the data table from the detected length of the guide band 60. For example, if the control unit 116 detects that the length of the guide band 60 is 90 cm, it determines the SAR limit value to be 1.5 W / kg based on the data table.

[0107] Next, in changing the imaging parameters (step S3), the control unit 116 causes the operation unit 118 to display the detected length of the guide band 60 and the determined SAR limit value. The imaging staff checks the content displayed on the operation unit 118, decides on the imaging parameters, and inputs instructions to the operation unit 118. Based on the instructions from the operation unit 118, the control unit 116 changes the imaging parameters so as to achieve the SAR limit value, and performs imaging of the subject 100. This makes it possible to prevent damage to the receive coil 51A.

[0108] Furthermore, it goes without saying that the present invention is not limited to the above-described embodiment, and various modifications are possible. [Explanation of symbols]

[0109] 10 Medical imaging diagnostic systems 20 MRI machine 32 tables 34 Movable top plate 36 Moving Rail 41 spaces 50, 50A, 50B, 50C, 50D, 50E, 50F receiving coil unit 51, 51A, 51B receiving coils 52 Coil element 55 Plate-shaped members 56 Coil cover 57 Main body 60 Guide Band 61 Coil Connector 62 Band Hook 64 Handle 66 Buckle 68 Rail Runner 76 Wearable Sensor 77 Length Sensor 78 Transmission Line 100 subjects

Claims

1. A band member; a first connector and a second connector provided at both ends of the band member to connect the band member to a table; a receiving coil including a plurality of coil elements for receiving nuclear magnetic resonance signals from a subject; a hook member disposed on the receiving coil, the hook member holding the band member so that the receiving coil can slide along the band member; A receiving coil unit comprising:

2. The receive coil unit according to claim 1 , wherein the receive coil does not have the hook members at both ends, but has weight members at both ends.

3. the receiving coil includes the plurality of coil elements and a plurality of plate-like members that support the plurality of coil elements and are arranged at intervals; The plurality of plate-like members are configured to be foldable, The receiver coil unit according to claim 1 , wherein the hook member is disposed outside the plurality of plate-shaped members.

4. The receive coil unit according to claim 1 , wherein the receive coil includes a flexible coil cover that covers the periphery of the plurality of coil elements.

5. The receive coil unit according to claim 1 , wherein the receive coil includes the plurality of coil elements and a rigid body that holds the plurality of coil elements.

6. The receiver coil unit according to claim 1 , wherein the first connector comprises a length adjustment mechanism and a tightening mechanism for the band member.

7. A receiving coil unit as described in any one of claims 1 to 6, wherein the first connecting device includes a length measuring sensor for measuring the length of the band member and / or a connection confirmation sensor for confirming whether or not the first connecting device is connected, and a transmission line for transmitting a detection signal from the length measuring sensor and / or the connection confirmation sensor to the receiving coil.

8. A receiving coil unit according to any one of claims 1 to 6; a table having a movable top plate on which a subject is placed; a magnetic resonance imaging apparatus including a processor for processing the nuclear magnetic resonance signals received by the receiving coil unit; A medical imaging diagnostic system comprising:

9. The movable top plate includes a moving rail along the longitudinal direction and to which the second connector is slidably connected. The medical image diagnostic system according to claim 8 .

10. The table includes a retraction rail for retracting the receiving coil unit. The medical image diagnostic system according to claim 9 .

11. the receiving coil unit includes a coil connector; The table has a storage space for storing the coil connector. The medical image diagnostic system according to claim 10.

12. The receiving coil unit according to claim 1 ; a length measuring sensor provided on the first connector for measuring the length of the band member and a connection confirmation sensor for confirming whether the first connector is connected or not; and a transmission line for transmitting detection signals from the length measuring sensor and the connection confirmation sensor to the receiving coil. a magnetic resonance imaging device including a processor for processing the nuclear magnetic resonance signals received by the receiving coil unit and an input receiving device; the processor determines an SAR limit value based on the detection signal from the length measuring sensor, and displays the SAR limit value on the input receiving device; the input accepting device accepts changes to imaging parameters; Medical imaging diagnostic system.

Images