High frequency coil unit and magnetic resonance imaging device

Abstract

To improve an operator's work efficiency at the time of positioning of an imaging part with a local coil and to inhibit re-imaging from being caused by a subject's positional deviation.SOLUTION: A coil unit comprises a coil and a form. The coil is provided at a position of a housing of the coil, at which a subject is in contact and can be compressed by deaeration and be expanded by atmosphere opening.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The embodiments disclosed in the present specification and drawings relate to a radio frequency coil unit and a magnetic resonance imaging apparatus. [Background technology]

[0002] A magnetic resonance imaging (MRI) system is an imaging device that excites the nuclear spins of a subject placed in a static magnetic field with radio frequency (RF) signals at the Larmor frequency, and generates images by reconstructing the magnetic resonance (MR) signals generated from the subject as a result of the excitation. Magnetic resonance imaging systems can collect magnetic resonance signals from the subject non-invasively.

[0003] In conventional MRI systems, to fix the patient's imaging site, e.g., the head, to a head coil (a local coil), a fixture such as a flexible pad must be inserted between the patient's head and the head coil. After the patient's head is positioned in the head coil, the operator inserts the pad between the patient's head and the inner wall of the head coil's housing. This operation can result in the patient's head becoming misaligned. Furthermore, if the operator makes contact with the patient's head during the pad insertion process, headphones worn on the patient's head may become displaced. Therefore, inserting the pad is a time-consuming task for the operator. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-73294 A Summary of the Invention [Problem to be solved by the invention]

[0005] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to improve the work efficiency of the operator when aligning the imaging region with the local coil and to suppress re-imaging due to positional deviation of the subject. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described below can also be positioned as other problems. [Means for solving the problem]

[0006] A coil unit according to an embodiment includes a coil and a foam. The foam is provided at a position on the coil housing where the foam comes into contact with the subject, and is capable of being compressed by degassing and expanding by being exposed to the atmosphere. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a block diagram showing the overall configuration of an MRI apparatus equipped with a high-frequency coil unit according to an embodiment. [Figure 2] Figure 2(A) is a front view showing the compressed state of the foam provided in the high-frequency coil unit according to the embodiment, Figure 2(B) is a front view showing the compressed state of the foam of the high-frequency coil unit according to the embodiment when worn on a patient, and Figure 2(C) is a front view showing the expanded state of the foam of the high-frequency coil unit according to the embodiment when worn on a patient. [Figure 3] FIG. 3 is a block diagram showing the functions of an MRI apparatus including a high-frequency coil unit according to an embodiment. [Figure 4] FIG. 4 is a flowchart showing the operation of an MRI apparatus including a high-frequency coil unit according to the embodiment. [Figure 5] FIG. 5(A) is a front view showing a compressed state of the foam of the high-frequency coil unit according to the first modified embodiment when worn on a patient, and FIG. 5(B) is a front view showing an expanded state of the foam of the high-frequency coil unit according to the first modified embodiment when worn on a patient. [Figure 6]FIG. 6(A) is a front view showing a compressed state of the foam of the high-frequency coil unit according to the second modified embodiment when worn on a patient, and FIG. 6(B) is a front view showing an expanded state of the foam of the high-frequency coil unit according to the second modified embodiment when worn on a patient. [Figure 7] Figure 7(A) is a front view showing the compressed state of the foam of a high-frequency coil unit according to a third modified embodiment attached to a first patient, Figure 7(B) is a front view showing the expanded state of the foam of a high-frequency coil unit according to a third modified embodiment attached to a first patient, and Figure 7(C) is a front view showing the expanded state of the foam of a high-frequency coil unit according to the third modified embodiment attached to a second patient. [Figure 8] Figure 8(A) is a front view showing the compressed state of the foam provided in the high-frequency coil unit according to the fourth modified embodiment, Figure 8(B) is a front view showing the compressed state of the foam of the high-frequency coil unit according to the fourth modified embodiment when worn on a patient, and Figure 8(C) is a front view showing the expanded state of the foam of the high-frequency coil unit according to the fourth modified embodiment when worn on a patient. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of a radio frequency coil unit and a magnetic resonance imaging (MRI) apparatus will be described in detail with reference to the drawings.

[0009] FIG. 1 is a block diagram showing the overall configuration of an MRI apparatus equipped with a high-frequency coil unit according to an embodiment.

[0010] FIG. 1 shows an MRI apparatus 1 according to an embodiment. The MRI apparatus 1 includes a magnet gantry 10, a local coil unit (e.g., a head coil unit 20), a bed 30, a control cabinet 40, an image processing device (e.g., a console) 50, a degassing pump 60, and a tube 70. The degassing pump 60 may be any pump capable of degassing, such as a vacuum pump or a hand pump. The magnet gantry 10, the head coil unit 20, and the bed 30 are typically arranged in an examination room, which is a shielded room. Meanwhile, the control cabinet 40 and the vacuum pump serving as the degassing pump 60 are typically arranged in a room called a machine room, and the console 50 is typically arranged in an operation room. Therefore, although the degassing pump 60 arranged in the machine room is not an essential component of the MRI apparatus 1, the following description will be given assuming that it is a component of the MRI apparatus 1 unless otherwise specified. If the degassing pump 60 is a hand pump, the degassing pump 60 may be arranged in the examination room.

[0011] 1 illustrates a case where the MRI apparatus 1 employs a method (head first) in which a subject, for example, a patient U, is inserted into the magnet gantry 10 from the head side, but the present invention is not limited to this case. For example, the MRI apparatus 1 may employ a method (foot first or feet first) in which the patient U is inserted into the magnet gantry 10 from the feet side.

[0012] The magnetic gantry 10 includes a static magnetic field magnet 11, a gradient magnetic field coil 12, a WB (Whole Body) coil 13, etc. The static magnetic field magnet 11 of the magnetic gantry 10 is broadly classified into a tunnel type in which the magnet has a cylindrical magnetic structure, and an open type in which a pair of magnets are arranged above and below with an imaging space between them. Here, a case in which the static magnetic field magnet 11 is of the tunnel type will be described, but the present invention is not limited to this case.

[0013] The static magnetic field magnet 11 has a roughly cylindrical shape and generates a static magnetic field within a bore into which the patient U is transported. The bore is the space inside the cylinder of the magnet gantry 10. The static magnetic field magnet 11 is composed of, for example, a housing for holding liquid helium, a refrigerator for cooling the liquid helium to an extremely low temperature, and a superconducting coil inside the housing. Note that the static magnetic field magnet 11 may also be composed of a permanent magnet. Below, a case where the static magnetic field magnet 11 has a superconducting coil will be described.

[0014] The static magnetic field magnet 11 has a built-in superconducting coil, which is cooled to an extremely low temperature by liquid helium. In the excitation mode, the static magnetic field magnet 11 generates a static magnetic field by applying a current supplied from a static magnetic field power supply to the superconducting coil. After that, when the mode shifts to the persistent current mode, the static magnetic field power supply is disconnected. Once in the persistent current mode, the static magnetic field magnet 11 continues to generate a static magnetic field for a long period of time, for example, for more than one year.

[0015] The gradient magnetic field coil 12 has a roughly cylindrical shape similar to the static magnetic field magnet 11, and is placed inside the static magnetic field magnet 11. The gradient magnetic field coil 12 generates a gradient magnetic field using current (power) supplied from a gradient magnetic field power supply 41, which will be described later, and applies the gradient magnetic field to the patient U. The gradient magnetic field coil 12 includes an Xch coil that generates a gradient magnetic field in the X-axis direction, a Ych coil that generates a gradient magnetic field in the Y-axis direction, and a Zch coil that generates a gradient magnetic field in the Z-axis direction. Here, the Z-axis direction is the direction along the static magnetic field, the Y-axis direction is the vertical direction, and the X-axis direction is the direction perpendicular to both the Z-axis and the Y-axis.

[0016] Here, since eddy magnetic fields generated by eddy currents generated in association with the generation of gradient magnetic fields interfere with imaging, for example, an ASGC (Actively Shielded Gradient Coil) intended to reduce eddy currents may be used as the gradient magnetic field coil 12. The ASGC is a gradient magnetic field coil in which shield coils for suppressing leakage magnetic fields are provided outside main coils for forming the gradient magnetic fields in the X-axis, Y-axis, and Z-axis directions, respectively.

[0017] The WB coil 13, also called a whole-body coil, is installed inside the gradient magnetic field coil 12 in a roughly cylindrical shape so as to surround the patient U. The WB coil 13 functions as a transmitting coil. That is, the WB coil 13 transmits RF pulses to the patient U in accordance with RF pulse signals transmitted from an RF transmitter 42, which will be described later. Meanwhile, the WB coil 13 may also function as a receiving coil in addition to functioning as a transmitting coil that transmits RF pulses. In that case, the WB coil 13 serves as a receiving coil to receive MR signals emitted from the patient U due to excitation of atomic nuclei. The WB coil 13 is an example of an RF coil.

[0018] The head coil unit 20 includes a head coil (coil body) 21 and a form 22. The head coil 21 is placed close to the body surface of the head of the patient U. The head coil 21 may include multiple coil elements. A coil in which multiple coil elements are arranged in an array is sometimes called a PAC (Phased Array Coil). Note that, in this embodiment, a case where the local coil is a head coil will be described, but the present invention is not limited to this case. The local coil may be any coil that is used by fixing the patient's imaging region. Other examples of local coils include flex coils for the ankle or wrist.

[0019] The head coil 21 functions as a receive coil. That is, the head coil 21 receives the above-mentioned MR signals. However, the head coil 21 may be a transmit / receive coil that functions as a transmit coil that transmits RF pulses in addition to the function as a receive coil that receives MR signals. For example, some head coils 21 are transmit / receive coils. That is, the head coil 21 may be a transmit-only coil, a receive-only coil, or a dual-purpose coil. Note that a head coil 21 that functions at least as a transmit coil is an example of an RF coil.

[0020] In this embodiment, the head coil 21 of the head coil unit 20 is described as one of the components of the MRI apparatus 1, but there may be cases where the head coil 21 is not included in the configuration of the MRI apparatus 1. In this case, although the head coil 21 is not included in the configuration of the MRI apparatus 1, the head coil 21 and the MRI apparatus 1 are configured to be connectable to each other. More specifically, the head coil 21 and the bed top 32 of the MRI apparatus 1 are configured to be connectable to each other.

[0021] Here, in the MRI apparatus, in order to fix the head of the patient U to the head coil 21, it is conceivable to fix the patient's head to the head coil by inserting a fixing device such as a flexible pad between the head of the patient U and the head coil 21. After the position of the head of the patient U in the head coil 21 has been determined, the pad is inserted by the operator between the head of the patient U and the inner wall surface of the housing of the head coil 21, and therefore, during this operation, the position of the head of the patient U may become misaligned. Furthermore, if the operator comes into contact with the patient U during the pad insertion operation, the headphones worn on the head of the patient U may become misaligned, so the pad insertion operation is a time-consuming task for the operator.

[0022] Therefore, the MRI apparatus 1 includes a head coil unit 20 and a tube 70 connected to a degassing pump 60. The head coil unit 20 includes the head coil 21 described above as well as foam 22. The foam 22 is provided on the housing of the head coil 21 at a position that contacts the head of the patient U. The foam 22 is compressed by degassing and expands due to the repulsive force of foam such as urethane. The foam 22 is connected to the degassing pump 60 via the tube 70. The degassing pump 60 is provided outside the magnet gantry 10. The degassing pump 60 includes a degassing pump main body, a vacuum valve having one end connected to the tube 70, an open valve having one end open to the atmosphere, and a line that joins the other end of the vacuum valve and the other end of the open valve and connects to the degassing pump main body. The tube 70 is routed from the front side to the back side of the top surface of the bed top 32, extended along the longitudinal direction (z-axis direction) of the bed top 32, and connected to the degassing pump 60. When the bed top 32 moves in the z-axis direction, the distance between the form 22 of the head coil unit 20 arranged on the bed top 32 and the degassing pump 60 changes, so the tube 70 connecting the form 22 and the degassing pump 60 is installed with some leeway in length.

[0023] The foam 22 is compressed by degassing using the degassing pump 60. In other words, by opening the vacuum valve of the degassing pump 60, closing the release valve, and operating the degassing pump main body, the air inside the foam 22 is sucked into the degassing pump main body via the tube 70 and the vacuum valve, thereby compressing the foam 22. The foam 22 is also expanded by being released to the atmosphere by the degassing pump 60. In other words, by opening the vacuum valve and release valve of the degassing pump 60, the air flowing in from the release valve is sucked into the foam 22 via the vacuum valve and tube 70, thereby expanding the foam 22.

[0024] If the MRI apparatus 1 is provided with a degassing pump (not shown) for vacuum sealing the gradient magnetic field coil 12 that generates sound, the foam 22 may be connected to the degassing pump so that it also serves as a degassing pump. In this case, the MRI apparatus 1 does not need the degassing pump 60.

[0025] Fig. 2(A) is a front view showing a compressed state of the form 22 provided in the head coil unit 20. Fig. 2(B) is a front view showing a compressed state of the form 22 of the head coil unit 20 attached to the patient U. Fig. 2(C) is a front view showing an expanded state of the form 22 of the head coil unit 20 attached to the patient U.

[0026] 2(A), in order to prevent the head of the patient U from shifting in the left-right direction, the head coil unit 20 is provided with two foam pieces 22 on the left and right inner wall surfaces of the housing of the head coil 21, which are surfaces that come into contact with the head of the patient U. For example, the two foam pieces 22 on the left and right are provided at positions that allow them to come into contact with the left and right ears of the patient U wearing the head coil unit 20. Note that foams may also be provided on the upper and lower inner wall surfaces of the housing of the head coil 21.

[0027] An opening H is provided in the form 22. A tube 70 for degassing and venting to the atmosphere is connected to the opening H of the form 22. The form 22 is compressed as shown in FIG. 2(A) by degassing the inside of the form 22 through the tube 70 using the degassing pump 60. With the form 22 in the compressed state, the head coil unit 20 is attached to the head of the patient U placed on the table top 32 (shown in FIG. 1) (shown in FIG. 2(B)). Then, once the position of the patient U's head relative to the head coil 21 is determined, the inside of the form 22 is vented to the atmosphere through the tube 70, causing the form 22 to expand (shown in FIG. 2(C)). In other words, the form 22 is expanded using the return force of the compression of the form 22 rather than by intake of air from the pump. The expansion of the form 22 allows the head of the patient U to be fixed to the head coil 21. Imaging of the head of the patient U is performed with the form 22 in the expanded state.

[0028] After imaging is completed, the foam 22 is returned from the expanded state shown in Fig. 2(C) to the compressed state by degassing the foam 22 through the tube 70 using the degassing pump 60 (shown in Fig. 2(B)). With the foam 22 in the compressed state, the head coil unit 20 can be removed from the head of the patient U.

[0029] Returning to the explanation of Figure 1, the bed 30 comprises a bed body 31 and a bed top 32. The bed body 31 can move the bed top 32 in the vertical and horizontal directions, and moves the subject placed on the bed top 32 to a predetermined height before imaging. Thereafter, during imaging, the bed top 32 is moved horizontally to move the subject into the bore.

[0030] Next, we will explain the control cabinet 40. The control cabinet 40 includes gradient magnetic field power supplies 41 (for the X axis 41x, for the Y axis 41y, and for the Z axis 41z), an RF transmitter , an RF receiver 43, and a sequence controller .

[0031] The gradient magnetic field power supply 41 includes gradient magnetic field power supplies 41x, 41y, and 41z for each channel that drive coils that generate gradient magnetic fields in the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively. The gradient magnetic field power supplies 41x, 41y, and 41z output the required current independently for each channel in response to commands from a sequence controller 44. This enables the gradient magnetic field coil 12 to apply gradient magnetic fields (also called "gradient magnetic fields") in the X-axis direction, the Y-axis direction, and the Z-axis direction to the patient U.

[0032] The RF transmitter 42 generates an RF pulse signal based on an instruction from the sequence controller 44. The RF transmitter 42 transmits the generated RF pulse signal to the RF coil (the WB coil 13 or the head coil 21).

[0033] The MR signals received by the WB coil 13 and the head coil 21, more specifically, the MR signals received by each coil element in the head coil 21, are transmitted to the RF receiver 43. The output lines of each coil element and the output line of the WB coil 13 are called channels. For this reason, the MR signals output from each coil element and the WB coil 13 are sometimes called channel signals. The channel signals received by the WB coil 13 are also transmitted to the RF receiver 43.

[0034] The RF receiver 43 converts the channel signals from the WB coil 13 and the head coil 21, i.e., the MR signals, into analog to digital (AD) signals and outputs them to a sequence controller 44. The digitally converted MR signals are sometimes called raw data.

[0035] The sequence controller 44 performs imaging of the patient U by driving the gradient magnetic field power supply 41, the RF transmitter 42, and the RF receiver 43 under the control of the console 50. When raw data is received from the RF receiver 43 by imaging, the sequence controller 44 transmits the raw data to the console 50.

[0036] The sequence controller 44 includes a processing circuit (not shown). This processing circuit is configured with hardware such as a processor that executes a predetermined program, an FPGA (Field Programmable Gate Array), and an ASIC (Application Specific Integrated Circuit).

[0037] Next, we will explain the console 50. The console 50 includes a processing circuit 51, a memory 52, an input interface 53, and a display .

[0038] The processing circuit 51 refers to a processor such as a dedicated or general-purpose CPU (Central Processing Unit) or MPU (Microprocessor Unit), as well as an application-specific integrated circuit (ASIC) and a programmable logic device. Examples of programmable logic devices include a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA). The processing circuit 51 reads and executes a program stored in the memory 52 or directly embedded in the processing circuit 51, thereby controlling the operation of the sequence controller 44 and performing imaging according to a pulse sequence to generate an MR image. The processing circuit 51 is an example of a processing unit.

[0039] Furthermore, the processing circuit 51 may be configured by a single processing circuit or may be configured by a combination of multiple independent processing circuit elements. In the latter case, multiple memories 52 may store programs corresponding to the functions of the multiple processing circuit elements, respectively, or one memory 52 may store programs corresponding to the functions of the multiple processing circuit elements.

[0040] The memory 52 includes semiconductor memory elements such as RAM (Random Access Memory) and flash memory, a hard disk, an optical disk, etc. The memory 52 may also include portable media such as a USB (Universal Serial Bus) memory and a DVD (Digital Video Disk). The memory 52 stores various processing programs (including application programs and an OS (Operating System)) used in the processing circuit 51, data required for executing the programs, and medical images. The OS may also include a GUI (Graphical User Interface) that makes extensive use of graphics to display information to the operator on the display 54 and enables basic operations to be performed via the input interface 53. The memory 52 is an example of a storage unit.

[0041] The input interface 53 includes an input device that can be operated by an operator and an input circuit that inputs signals from the input device. The input device can be realized by a trackball, a switch, a mouse, a keyboard, a touchpad that performs input operations by touching the operation surface, a touchscreen that combines a display screen and a touchpad, a non-contact input device that uses an optical sensor, a voice input device, etc. When the operator operates the input device, the input circuit generates a signal corresponding to the operation and outputs it to the processing circuit 51. The input interface 53 is an example of an input unit.

[0042] The display 54 is configured by a general display output device such as a liquid crystal display or an OLED (Organic Light Emitting Diode) display. The display 54 displays various information under the control of the processing circuit 51. The display 54 is an example of a display unit.

[0043] Under the control of the processing circuitry 51, the console 50 arranges the raw data transmitted from the sequence controller 44 in k-space and stores it in the memory 52. ​​Under the control of the processing circuitry 51, the console 50 performs reconstruction processing such as an inverse Fourier transform on the k-space data stored in the memory 52 to generate desired MR images of the inside of the patient U. Then, under the control of the processing circuitry 51, the console 50 stores the generated various MR images in the memory 52.

[0044] Next, the function of the MRI apparatus 1 will be described with reference to FIG.

[0045] FIG. 3 is a block diagram showing the functions of the MRI apparatus 1. As shown in FIG.

[0046] 3, the processing circuit 51 realizes an opening control function F1, an imaging function F2, and a degassing control function F3 by reading and executing a computer program stored in the memory 52 or directly incorporated in the processing circuit 51. The following description will be given taking as an example a case where the functions F1 to F3 function as software by executing a computer program, but all or part of the functions F1 to F3 may be realized by a circuit such as an ASIC.

[0047] The release control function F1 includes a function for controlling the operation of the degassing pump 60 so as to open the inside of the form 22 to the atmosphere based on an input signal from the input interface 53. Specifically, the release control function F1 opens the vacuum valve of the degassing pump 60 based on an input signal from the input interface 53, and opens the release valve of the degassing pump 60, thereby causing air flowing in from the release valve to be sucked into the form 22 via the vacuum valve and the tube 70, thereby expanding the form 22. The release control function F1 is an example of an release control unit.

[0048] The imaging function F2 includes a function to perform imaging of the head of the patient U by controlling the magnet gantry 10, the head coil unit 20, the bed 30, etc., and a function to generate a desired MR image of the inside of the patient U based on the MR signal from the head coil 21. Here, imaging means positioning imaging (or pre-scan) and imaging according to one or more pulse sequences, and may also include the movement of the bed top 32 (insertion into / retraction from the bore). The imaging function F2 is an example of an imaging section.

[0049] The degassing control function F3 includes a function for controlling the operation of the degassing pump 60 so that degassing of the form 22 is linked to the end of imaging. Specifically, the degassing control function F3 opens the vacuum valve of the degassing pump 60, closes the release valve of the degassing pump 60, and operates the degassing pump main body of the degassing pump 60 so that degassing of the form 22 is linked to the end of imaging, thereby causing the air in the form 22 to be sucked into the degassing pump main body via the tube 70 and the vacuum valve, thereby compressing the form 22. The degassing control function F3 is an example of a degassing control unit.

[0050] Next, the operation of the MRI apparatus 1 will be described with reference to FIG.

[0051] Fig. 4 is a flowchart showing the operation of the MRI apparatus 1. In Fig. 4, the reference numerals "ST" followed by numbers indicate the steps of the flowchart.

[0052] First, in step ST1, the degassing control function F3 controls the operation of the degassing pump 60 to degas the inside of the form 22 via the tube 70, thereby compressing the form 22 (shown in FIG. 2(A)). Although the form 22 is compressed in step ST8 when imaging a patient prior to patient U, there is a possibility that the form 22 is not sufficiently compressed in step ST8, or that air has flowed into the form 22 from the compressed state of the form 22 in step ST8 until the imaging of patient U, resulting in an insufficient compression state of the form 22.

[0053] Next, in step ST2, the patient U is placed on the bed top 32 of the bed 30. In step ST2, the patient U is placed in a supine position on the bed top 32 in the lowered position, and the bed top 32 on which the patient U is placed is raised to adjust the height of the bed top 32.

[0054] Next, in step ST3, a local coil unit, for example, the head coil unit 20, with the form 22 in a compressed state is attached to the patient U placed on the bed top 32. In step ST3, the head coil unit 20 with the form 22 in a compressed state is attached to the head of the patient U (shown in FIG. 2(B)), and the cable of the head coil 21 is connected to the coil port.

[0055] Subsequently, in step ST4, the head of the patient U placed on the bed top 32 is aligned with the head coil 21.

[0056] When the alignment of the patient U with respect to the head coil 21 is completed, the release control function F1 inflates the foam 22 in step ST5 by controlling the operation of the degassing pump 60 based on an input signal from the input interface 53 to open the interior of the foam 22 to the atmosphere (shown in FIG. 2(C)). In step ST5, the foam 22 is inflated to fit the shape of the patient U's head, thereby fixing the head to the head coil 21. In this way, the compressed foam 22 can be inflated to fix the patient U's head to the head coil 21, eliminating the need to insert a pad after positioning the patient U's head. Furthermore, the patient U can obtain cushioning and a feel equivalent to that of a typical pad from the inflated foam 22.

[0057] In step ST6, the imaging function F2 inserts the bed top 32 on which the patient U is placed into the bore of the magnet gantry 10. Then, in step ST7, the imaging function F2 performs imaging of the head of the patient U to generate an MR image.

[0058] The degassing control function F3 controls the operation of the degassing pump 60 so that the degassing of the foam 22 is synchronized with the end of imaging, and compresses the foam 22 by degassing the foam 22 via the tube 70 (shown in FIG. 2(B)). For example, the degassing control function F3 controls the operation of the degassing pump 60 so that the foam 22 is degassed immediately after the end of imaging, thereby degassing the foam 22. In step ST7, the head of the patient U is released from the head coil 21.

[0059] In step ST8, the imaging function F2 retracts the bed top 32 on which the patient U is placed from the bore of the magnet gantry 10. The order of steps ST8 and ST9 does not matter, and they may be performed simultaneously in parallel. In step ST10, the cable of the head coil 21 is removed from the coil port, and the head coil unit 20, with the form 22 in a compressed state, is removed from the head of the patient U.

[0060] As described above, with the head coil unit 20 (and the MRI apparatus 1 including the same), the head of the patient U can be fixed to the head coil 21 simply by expanding the foam 22 attached in a compressed state, thereby improving the efficiency of the operator's work when aligning the head of the patient U with the head coil 21. Furthermore, with the head coil unit 20 and the MRI apparatus 1, there is no need to insert a fixture between the head of the patient U and the inner wall surface of the housing of the head coil 21, and the head is fixed along the shape of the head, so there is no misalignment of the head during the insertion work, and re-imaging due to misalignment of the head can be suppressed. Furthermore, with the head coil unit 20 and the MRI apparatus 1, there is no need to insert a fixture between the head of the patient U and the inner wall surface of the housing of the head coil 21, and the head is fixed along the shape of the head, so the burden on the patient U during alignment can be reduced.

[0061] (First Modification) In the head coil unit 20A according to the first modification, in order to compress the form 22 described above evenly over the surface, a contact-side member 23 made of a hard material is provided between the form 22 and the head coil 21. In other words, the surface of the form 22 facing the head of the patient U is made of a softer material than the opposite surface (the side in contact with the housing of the head coil 21).

[0062] Fig. 5(A) is a front view showing the compressed state of the foam 22 of the head coil unit 20A worn by a patient, and Fig. 5(B) is a front view showing the expanded state of the foam 22 of the head coil unit 20A worn by a patient.

[0063] As shown in Figures 5(A) and (B), the head coil unit 20A includes a head coil 21, a form 22 with an opening H, and a contact-side member 23. Similar to the head coil unit 20 (shown in Figure 2), the head coil unit 20A is provided with two forms 22 on the left and right to prevent the head of the patient U from shifting left and right. In addition, a tube 70 for degassing and venting to the atmosphere is connected to the opening H of the form 22. In Figures 5(A) and (B), the same members as those in Figures 2(A) to (C) are designated by the same reference numerals, and their description will be omitted.

[0064] The contact side member 23 is made of a hard material of the head coil 21 of the foam 22 in order to compress the foam 22 evenly over its surface.

[0065] The foam 22 is compressed by evacuating the foam 22 through the tube 70 using the degassing pump 60. The hard contact side member 23 on the outside of the foam 22 allows the foam 22 to be compressed evenly across its surface. With the foam 22 in a compressed state, the head coil unit 20A is attached to the head of the patient U placed on the bed top 32 (shown in FIG. 5(A)). Then, once the position of the patient U's head relative to the head coil 21 has been determined, the foam 22 is opened to the atmosphere through the tube 70, causing the foam 22 to expand (shown in FIG. 5(B)). The foam 22 is expanded using the force of the foam 22 returning to its compressed state, rather than by drawing air from the pump. The expansion of the foam 22 allows the head of the patient U to be fixed to the head coil 21. Imaging of the patient U's head is performed with the foam 22 in an expanded state.

[0066] After imaging is completed, the foam 22 is returned from the expanded state shown in Fig. 5(B) to the compressed state by degassing the foam 22 through the tube 70 using the degassing pump 60 (shown in Fig. 5(A)). With the foam 22 in the compressed state, the head coil unit 20A can be removed from the head of the patient U.

[0067] As described above, according to the head coil unit 20A (and the MRI apparatus 1 including it), in addition to the above-mentioned effects, the hard contact side member 23 on the outside of the form 22 can compress the form 22 evenly over its surface.

[0068] (Second Modification) The head coil unit 20B according to the second modification includes a form 22B with a plurality of openings to uniformly compress the form 22 described above. Tubes 70B are connected to the respective openings of the form 22B. The openings are preferably arranged at a plurality of positions evenly distributed on the contact surface of the form 22B with the head coil 21.

[0069] Fig. 6(A) is a front view showing the compressed state of the foam 22 of the head coil unit 20B worn by the patient, and Fig. 6(B) is a front view showing the expanded state of the foam 22 of the head coil unit 20B worn by the patient.

[0070] As shown in Figures 6(A) and (B), the head coil unit 20B includes a head coil 21 and a form 22B with a plurality of openings HBn (for example, two HB1 and HB2). Similar to the head coil unit 20 (shown in Figure 2), the head coil unit 20B is provided with two forms 22B on the left and right to prevent the head of the patient U from shifting left and right. Furthermore, a tube 70B for degassing and venting to the atmosphere is connected to each of the openings HB1 and HB2 of the form 22B. In Figures 6(A) and (B), the same members as those in Figures 2(A) to (C) are designated by the same reference numerals, and their description will be omitted.

[0071] The foam 22B is compressed by evacuating the interior of the foam 22B via the tube 70B using the degassing pump 60. By evacuating the interior of the foam 22B through the openings HB1 and HB2, the foam 22B can be compressed evenly across its surface. With the foam 22B in a compressed state, the head coil unit 20B is attached to the head of the patient U placed on the table top 32 (shown in FIG. 1) (shown in FIG. 6A). Once the position of the patient U's head relative to the head coil 21 is determined, the interior of the foam 22B is opened to the atmosphere via the tube 70B, causing the foam 22B to expand (shown in FIG. 6B). The foam 22B is expanded not by the intake of air from the pump, but by the return force of the compressed foam 22B. The expansion of the foam 22B allows the head of the patient U to be fixed to the head coil 21. With the foam 22B in an expanded state, imaging of the patient U's head is performed.

[0072] After imaging is completed, the foam 22B returns from the expanded state shown in Fig. 6(B) to the compressed state by degassing the foam 22B through the tube 70B using the degassing pump 60 (shown in Fig. 6(A)). With the foam 22B in the compressed state, the head coil unit 20B can be removed from the head of the patient U.

[0073] As described above, in addition to the above-mentioned effects, the head coil unit 20B (and the MRI apparatus 1 equipped with it) can evacuate the foam 22B from multiple openings that are evenly spread out inside the foam 22B, thereby compressing the foam 22B evenly across its surface.

[0074] (Third Modification) A head coil unit 20C according to the third modification is provided with a form 22C having a plurality of stages of form elements in the thickness direction in order to accommodate changes in the size of the imaging region.

[0075] Fig. 7(A) is a front view showing a compressed state of the form 22C of the head coil unit 20C worn by a first patient, Fig. 7(B) is a front view showing an expanded state of the form 22C of the head coil unit 20C worn by a first patient, and Fig. 7(C) is a front view showing an expanded state of the form 22C of the head coil unit 20C worn by a second patient.

[0076] As shown in Figures 7(A) to 7(C), the head coil unit 20C includes a head coil 21 and a form 22C. Similar to the head coil unit 20 (shown in Figure 2), the head coil unit 20C is provided with two forms 22C on the left and right to prevent the head of the patient U from shifting left and right. A tube 70C for degassing and venting to the atmosphere is connected to the form 22C. In Figures 7(A) to 7(C), the same members as those in Figures 2(A) to 2(C) are designated by the same reference numerals, and their description will be omitted.

[0077] The foam 22C is composed of multiple foam elements in the thickness direction. For example, the foam 22C has two layers in the thickness direction: an inner foam 221 and an outer foam 222. The tube 70C has an inner tube 701 corresponding to the inner foam 221 and an outer tube 702 corresponding to the outer foam 222. The inner foam 221 has an opening HC1 and is connected to the inner tube 701 via this opening HC1. The outer foam 222 has an opening HC2 and is connected to the outer tube 702 via this opening HC2. Note that the multiple foam elements in the thickness direction are not limited to two layers of foam elements, and may be three or more foam elements.

[0078] The foams 221, 222 are compressed by degassing the foams 221, 222 via the tubes 701, 702 using the degassing pump 60. If the patient U is a first patient (e.g., an adult) U1 with a large head, the head coil unit 20C is attached to the head of the adult U1 placed on the bed top 32 (shown in FIG. 1) with the foams 221, 222 compressed (shown in FIG. 7(A)). Then, once the head position of the adult U1 is determined, the multiple stages of the foams 221, 222 are inflated sequentially, starting from the head side, which is the imaging region where the head coil unit 20C is attached. This is because preferentially inflating the foam element on the side that comes into contact with the head, it is possible to fix the head in accordance with the shape of the head and to reduce the load on the head.

[0079] First, the interior of the inner foam 221 is opened to the atmosphere via the inner tube 701, causing the inner foam 221 to expand (as shown in FIG. 7(B)). The inner foam 221 is expanded using the force of the inner foam 221 returning to its compressed state, rather than by drawing air from a pump. The expansion of the inner foam 221 allows the head of adult U1, who has a large head size, to be fixed to the head coil 21. Therefore, there is no need to expand the outer foam 222. Imaging of the head of adult U1 is performed with the inner foam 221 in an expanded state.

[0080] After imaging is completed, the inner foam 221 is deaerated from its expanded state shown in Fig. 7(B) via the inner tube 701 by the deaerating pump 60, so that the inner foam 221 returns to its compressed state (shown in Fig. 7(A)). With the foams 221, 222 in a compressed state, the head coil unit 20C can be removed from the head of the adult U1.

[0081] On the other hand, if the patient U is a second patient (e.g., a child) U2 with a small head, once the head position of the child U2 is determined, the multi-stage foams 221, 222 are inflated in order, starting from the head side, which is the imaging region where the head coil unit 20C is attached. First, the inner foam 221 is opened to the atmosphere via the inner tube 701, thereby inflating the inner foam 221. The inner foam 221 is inflated using the force of the inner foam 221 returning to its original state rather than by intake of air from the pump. However, at this stage, the head of the child U2, whose head size is small, cannot be fixed to the head coil 21. Therefore, the outer foam 222 is opened to the atmosphere via the outer tube 702, thereby inflating the outer foam 222 (as shown in FIG. 7(C)). The outer foam 222 is inflated using the force of the outer foam 222 returning to its original state rather than by intake of air from the pump. By expanding both foams 221, 222, the head of the child U2, whose head size is small, can be fixed to the head coil 21. Imaging of the head of the child U2 is performed with the forms 221, 222 in an inflated state.

[0082] 7(C) via the tubes 701 and 702 using the degassing pump 60, the foams 221 and 222 are degassed from the expanded state of the foams 221 and 222, and the foams 221 and 222 are returned to the compressed state. With the foams 221 and 222 in the compressed state, the head coil unit 20C can be removed from the head of the child U2.

[0083] As described above, the head coil unit 20C (and the MRI apparatus 1 including it) not only has the above-mentioned effects but also can accommodate changes in the size of the imaging region.

[0084] (Fourth Modification) The MRI apparatus 1 is not limited to one that degasses or releases the inside of the foam in conjunction with imaging. The MRI apparatus 1 may also be degassed or released to the atmosphere by an operator. In this case, the head coil unit 20D according to the fourth modification is provided with a foam 22D having an opening / closing part HD that can be opened and closed freely.

[0085] Fig. 8(A) is a front view showing a compressed state of the form 22D provided in the head coil unit 20D. Fig. 8(B) is a front view showing a compressed state of the form 22D of the head coil unit 20D attached to the patient U. Fig. 8(C) is a front view showing an expanded state of the form 22D of the head coil unit 20D attached to the patient U.

[0086] As shown in Figures 8(A) to 8(C), the head coil unit 20D includes a head coil 21 and a form 22D. Similar to the head coil unit 20 (shown in Figure 2), the head coil unit 20D is provided with two forms 22D on the left and right to prevent the head of the patient U from shifting left and right. In Figures 8(A) to 8(C), the same members as those in Figures 2(A) to 2(C) are designated by the same reference numerals and their description will be omitted.

[0087] The form 22D is provided with an opening / closing portion HD. An operator connects a detachable tube (not shown) for degassing and releasing to the atmosphere to the opening / closing portion HD of the form 22D. The form 22D is compressed as shown in FIG. 8(A) by degassing the interior of the form 22D through the tube using a degassing pump 60. The operator removes the tube from the form 22D and closes the opening / closing portion HD of the form 22D. With the form 22D in the compressed state, the head coil unit 20D is attached to the head of the patient U placed on the bed top 32 (shown in FIG. 1) (shown in FIG. 8(B)).

[0088] Then, once the position of the patient U's head relative to the head coil 21 has been determined, the operator opens the opening / closing portion HD of the form 22D, opening the interior of the form 22D to the atmosphere, causing the form 22D to enter an inflated state (shown in FIG. 8(C)). The form 22D is inflated not by intake of air from a pump, but by the force of the form 22D returning from compression. The expansion of the form 22D allows the head of the patient U to be fixed to the head coil 21. Imaging of the patient U's head is performed with the form 22D in an inflated state.

[0089] After imaging is completed, the operator connects a tube (not shown) to the opening / closing portion HD of the form 22D. The form 22D returns from the expanded state shown in FIG. 8(C) to a compressed state by degassing the form 22D through the tube using the degassing pump 60 (shown in FIG. 8(B)). With the form 22D in the compressed state, the head coil unit 20D can be removed from the head of the patient U.

[0090] As described above, the head coil unit 20D (and the MRI device 1 equipped with it) has the above-mentioned effects, and in addition, the form 22D can be degassed and opened to the atmosphere using a detachable tube (not shown), so there is no need to consider the routing of the tube 70 (shown in Figure 1).

[0091] According to at least one of the embodiments described above, it is possible to improve the work efficiency of the operator when aligning the imaging region with the local coil, and to suppress re-imaging due to positional deviation of the subject.

[0092] Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations of embodiments can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0093] 1...Magnetic resonance imaging (MRI) device 20, 20A, 20B, 20C, 20D...Local coil units (e.g., head coil units) 21...Local coil (e.g., head coil) 22, 22B, 22C, 22D...Form 221...Naidan Form 222...Outer Form 51...Processing circuit 60...Degassing pump 70, 70B, 70C...Tube 701...Inner tube 702...Outer tube F1...Opening control function F2...Image capture function F3…Degassing control function

Claims

1. A head coil, left and right foams provided separately at positions on the housing of the head coil that come into contact with the patient's left and right ears, respectively, each foam having a plurality of openings for connecting a plurality of tubes, the left and right foams being compressed by degassing through the plurality of openings and being expandable by being exposed to the atmosphere; Equipped with The plurality of openings provided in each foam are arranged at a plurality of positions evenly spread on the surface of each foam opposite to the patient side. High frequency coil unit for the head.

2. The surface of the foam facing the patient is made of a softer material than the opposite surface.

2. The high frequency coil unit for a head according to claim 1.

3. The high frequency coil unit for a head according to claim 1 or 2; a degassing pump for degassing the foam through the plurality of openings in the foam; A magnetic resonance imaging apparatus comprising:

4. The degassing pump is provided outside the magnet pedestal.

4. The magnetic resonance imaging apparatus according to claim 3.

5. the plurality of tubes; the plurality of tubes are connected to the plurality of openings of the foam, respectively; 5. The magnetic resonance imaging apparatus according to claim 3.

6. The foam is composed of multiple foam elements in the thickness direction.

6. A magnetic resonance imaging apparatus according to claim 3.

7. Among the foam elements in the plurality of stages, the foam elements are inflated in order from the foam element on the head side.

7. The magnetic resonance imaging apparatus according to claim 6.

8. a degassing control unit that controls the operation of the degassing pump so that degassing of the foam is synchronized with the end of imaging; 8. The magnetic resonance imaging apparatus according to claim 3, further comprising:

9. a release control unit that controls the operation of the degassing pump based on an input signal from an input unit so as to release the inside of the foam to the atmosphere; 9. The magnetic resonance imaging apparatus according to claim 3, further comprising:

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