Reception coil unit and magnetic resonance imaging apparatus

Abstract

To provide a reception coil unit capable of suppressing heat transfer from a heater element arranged inside a coil cover to a subject, and releasing heat generated from the heater element or the subject from between the coil cover and the subject, and to provide a magnetic resonance imaging apparatus equipped with the reception coil unit.SOLUTION: A reception coil unit includes: a coil element for receiving a signal generated from a subject; a heater element connected to the coil element; a coil cover for covering the outside of the coil element and the heater element; and a plurality of buffer materials having a convex shape toward a subject side, which are arranged at a position overlapping a region of the heater element viewed from the subject side of the surface on a side in contact with the subject of the coil cover.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to a receiving coil unit and a magnetic resonance imaging (MRI) apparatus.

Background Art

[0002] In an MRI apparatus, a subject placed in a static magnetic field is irradiated with high-frequency electromagnetic waves to excite nuclear spins in the subject, for example, nuclear spins of hydrogen atoms. When the excited nuclear spins return to the equilibrium state, a nuclear magnetic resonance (NMR) signal generated is detected and signal-processed to image the distribution of hydrogen atomic nuclei in the living body.

[0003] A receiving coil that receives an NMR signal from a subject is preferably arranged close to the subject in order to obtain high sensitivity. Therefore, receiving coils are prepared for different applications according to the shape of the imaging target site, such as the head, abdomen, and limbs.

[0004] Patent Document 1 describes an RF coil unit for infants that can attach an abdominal coil. The RF coil unit described in Patent Document 1 is composed of a cushion material with unevenness on the surface that contacts the subject in a support part in which coil elements are housed.

[0005] Patent Document 2 describes a technique of interposing a buffer material between a subject and a receiving coil. Patent Document 3 describes a coil manufactured in the form of a flexible blanket.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The blanket-shaped abdominal receiving coil unit has a structure that is lighter and more flexible than an integrally molded coil in which internal coil elements and electrical components such as electric circuits are integrally formed with a coil cover such as resin. To achieve this, a flexible bag-shaped coil cover that covers the entire electrical component is used outside the internal electrical component. The electrical components housed inside the coil cover include elements that generate heat when irradiated with high-frequency electromagnetic wave energy. On the other hand, in the blanket-shaped receiving coil unit, due to the flexibility of the coil cover, the coil cover adheres closely to the subject, making it difficult to release the heat from the subject, and heat tends to accumulate.

[0008] The technique described in Patent Document 1 aims to release the heat generated from infants with immature thermoregulation, but Patent Document 1 does not consider the heat generated from the heating element. Also, even if the cushioning material described in Patent Document 1 is applied to the blanket-shaped receiving coil unit, the cushioning material will be continuously arranged without gaps over the entire surface between the subject and the receiving coil unit. Therefore, since the cushioning material and the subject are in continuous close contact in the surface direction, it is difficult for heat to escape.

[0009] Regarding the technique described in Patent Document 2, the heat generated from the heating element is not considered, and since a cushioning material is interposed over the entire surface between the subject and the receiving coil, there is a problem that heat is difficult to escape.

[0010] The present disclosure has been made in view of such circumstances, and an object thereof is to provide a receiving coil unit that can suppress heat transfer from a heating element disposed inside a coil cover to a subject and can release the heat generated from the heating element or the subject from between the coil cover and the subject, and a magnetic resonance imaging apparatus including the same.

Means for Solving the Problem

[0011] The receiving coil unit according to the first aspect of the present disclosure includes a coil element that receives a signal generated from a subject, a heating element connected to the coil element, a coil cover that covers the outside of the coil element and the heating element, and a plurality of buffer members that are arranged at positions overlapping the region of the heating element when viewed from the subject side on the surface of the coil cover that contacts the subject and have a convex shape toward the subject side.

[0012] According to the first aspect, a plurality of buffer members are provided on the surface of the coil cover that contacts the subject, and the surface of the coil cover on the subject side has an uneven shape. The concave portions between the buffer members in this uneven shape function as air passages, and in a state where the receiving coil unit is attached to the subject, heat can be released from between the coil cover and the subject through the air passages of these concave portions. Further, the heat generated from the heating element disposed inside the coil cover is difficult to be transmitted to the subject due to the heat insulating effect of the air intervening between the coil cover and the subject.

[0013] The receiving coil unit according to the second aspect is the receiving coil unit according to the first aspect, and preferably, the thickness of the buffer member is 5 mm or less.

[0014] The receiving coil unit according to the third aspect is the receiving coil unit according to the first aspect or the second aspect, and the buffer member may be fixed by a structure attached to the surface of the coil cover.

[0015] The receiving coil unit according to the fourth aspect is the receiving coil unit according to any one of the first aspect to the third aspect, and the buffer member may be integrally formed with the coil cover.

[0016] The receiving coil unit according to the fifth aspect is the receiving coil unit according to any one of the first to fourth aspects, and includes a plurality of coil elements and a plurality of heating elements. A buffer material may be disposed at a position on the surface of the coil cover that overlaps each region of the plurality of heating elements when viewed from the subject side.

[0017] The receiving coil unit according to the sixth aspect is the receiving coil unit according to any one of the first to fifth aspects, and the coil cover may be a flexible bag-shaped cover that can be deformed according to the physique of the subject.

[0018] The receiving coil unit according to the seventh aspect is the receiving coil unit according to any one of the first to sixth aspects, and the buffer material may be configured to include air bubbles.

[0019] The receiving coil unit according to the eighth aspect is the receiving coil unit according to any one of the first to sixth aspects, and the buffer material may be configured to have a hollow structure.

[0020] The receiving coil unit according to the ninth aspect is the receiving coil unit according to any one of the first to eighth aspects, and the buffer material may be configured using a heat insulating material.

[0021] The receiving coil unit according to the tenth aspect is the receiving coil unit according to any one of the first to ninth aspects, and the buffer material may not be disposed at the central position of the region of the heating element on the surface of the coil cover.

[0022] The receiving coil unit according to the eleventh aspect is the receiving coil unit according to any one of the first to tenth aspects, and the buffer material may not be disposed in a region on the surface of the coil cover that is separated from the region of the heating element by a predetermined distance or more.

[0023] The receiving coil unit according to the 12th aspect is the receiving coil unit according to any one of the 1st to 11th aspects, and the signal received by the coil element may be a nuclear magnetic resonance signal.

[0024] The receiving coil unit according to the 13th aspect is the receiving coil unit according to any one of the 1st to 12th aspects, and the heating element may be configured to include at least one of an inductor, a capacitor, and a diode.

[0025] The receiving coil unit according to the 14th aspect is the receiving coil unit according to any one of the 1st to 13th aspects, and the heating element may be configured to include a resonance circuit for removing the coupling between the transmission coil that irradiates the subject with a high-frequency magnetic field and the coil element.

[0026] The magnetic resonance imaging apparatus according to the 15th aspect includes the receiving coil unit according to any one of the 1st to 14th aspects, and generates a magnetic resonance image from the nuclear magnetic resonance signal received using the receiving coil unit.

Advantages of the Invention

[0027] According to the present invention, heat transfer from the heating element disposed inside the coil cover to the subject can be suppressed, and heat generated from the heating element or the subject can be dissipated from between the coil cover and the subject.

Brief Description of the Drawings

[0028]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

[0029] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and the accompanying drawings, components having the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

[0030] [Description of MRI Apparatus] FIG. 1 is an external perspective view of an MRI apparatus 20 to which a receiving coil unit 10 according to an embodiment of the present invention is applied. The MRI apparatus 20 includes a gantry 22 which is a device main body, a bed device 30 on which a subject is placed, and a receiving coil unit 10 which receives a signal from the subject.

[0031] The gantry 22 is arranged in an electromagnetically shielded room (examination room or imaging room) of a medical facility such as a hospital. The subject is placed on the top plate 34 of the table 32 of the bed device 30 and is conveyed toward the gantry 22 by the moving operation of the table 32. The gantry 22 has a bore 24 which is an imaging space, and the table 32 moves within this bore 24.

[0032] FIG. 2 is a schematic diagram showing the internal configuration of the MRI apparatus 20. The MRI apparatus 20 includes a static magnetic field generating magnet 102, a gradient magnetic field coil 104, and a transmission coil 106.

[0033] The static magnetic field generating magnet 102 generates a uniform static magnetic field in the bore 24. The gradient magnetic field coil 104 generates a gradient magnetic field in the bore 24. The transmission coil 106 is a radio frequency (RF) coil that generates a high-frequency magnetic field for causing a nuclear magnetic resonance (NMR) signal in the atomic nuclei that make up the tissue of the subject 100 placed in the bore 24.

[0034] A receiving coil unit 10 is attached to the subject 100 placed on the top plate 34. By moving the table 32 on which the subject 100 is placed into the bore 24, the examination site (imaging target site) of the subject 100 is positioned at the center of the static magnetic field in the bore 24.

[0035] The MRI apparatus 20 further includes a sequencer 108, a high-frequency magnetic field generator 110, a gradient magnetic field power supply 112, a control unit 116, and an operation unit 118. Note that the power supply, control, and signal processing systems of the MRI apparatus 20 are arranged outside an electromagnetically shielded room (for example, a machine room and / or an operation room), and are electrically connected to the gantry 22 via cables. The sequencer 108 sends commands to the high-frequency magnetic field generator 110 and the gradient magnetic field power supply 112 according to an imaging sequence, and generates a high-frequency magnetic field and a gradient magnetic field, respectively.

[0036] The generated high-frequency magnetic field is applied to the subject 100 as a pulsed high-frequency magnetic field (RF pulse) through the transmission coil 106. The NMR signal generated from the subject 100 is received by the receiving coil unit 10, and is detected by the receiver 114.

[0037] Note that the gradient magnetic field coil 104 is composed of gradient magnetic field coils in three directions of X, Y, and Z, and generates gradient magnetic fields according to signals from the gradient magnetic field power supply 112, respectively.

[0038] The nuclear magnetic resonance frequency (detection reference frequency f0) used as the reference for detection in the receiver 114 is set by the sequencer 108. The sequencer 108 controls so that each part operates at a programmed timing and intensity. Among the programs, those that particularly describe the timing and intensity of RF pulses, gradient magnetic fields, and signal reception are called pulse sequences.

[0039] Although various pulse sequences are known according to the purpose, detailed explanations thereof are omitted here.

[0040] The control unit 116 controls the operations of each part of the MRI apparatus 20 via the sequencer 108. Further, the control unit 116 receives the signal detected by the receiver 114 and performs various signal processes such as image reconstruction. Note that the receiver 114 quadrature phase-detects the echo signal (NMR signal), which is an analog wave, with the set detection reference frequency f0, converts it into low data, and then transmits it to the control unit 116. This low data is also referred to as an echo signal or measurement data.

[0041] The control unit 116 receives various instruction inputs from the operation unit 118 and performs overall control of each part of the MRI apparatus 20. Further, the control unit 116 performs processes such as inverse Fourier transform of the echo signal in the spatial frequency domain received via the sequencer 108 to convert it into an image in the real space, and generates a magnetic resonance image (MRI image).

[0042] The control unit 116 is realized by a general-purpose computer such as a personal computer or a microcomputer. The control unit 116 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an input / output interface, etc.

[0043] In the control unit 116, various programs such as control programs stored in a ROM, a storage, etc. are expanded in a RAM, and the programs expanded in the RAM are executed by a CPU. Thereby, functions of each part of the MRI apparatus 20 are realized, and various arithmetic processes and control processes are executed via an input / output interface.

[0044] The operation unit 118 includes input devices such as a mouse and a keyboard, and functions as a part of a GUI (Graphical User Interface) that uses a display operation window of a display (not shown) to receive inputs from imaging staff.

[0045] That is, the operation unit 118 functions as a GUI for imaging staff to input activation, stop (including temporary stop), selection of a pulse sequence, imaging conditions, processing conditions, etc. of the MRI apparatus 20. Note that the operation unit 118 may include a voice input device.

[0046] 〔Description of the reception coil unit 10〕 The reception coil unit 10 is a blanket-shaped reception coil for the abdomen, has flexibility (flexibility) as a whole so as to be deformable according to the physique of the subject 100, and is configured to be thin and lightweight.

[0047] FIG. 3 is an exploded perspective view schematically showing the configuration of the reception coil unit 10 according to the embodiment. The reception coil unit 10 is an array coil configured for multi-channel, and includes a plurality of coil elements 52, a plurality of heating elements 54 which are electrical components connected to the respective coil elements 52, and a bag-shaped coil cover 56. The coil element 52 is a sub-coil of the array coil.

[0048] Each of the plurality of coil elements 52 functions as an antenna that receives an NMR signal generated from the biological tissue of the subject 100. Each coil element 52 is adjusted to resonate at a specific frequency. The specific frequency is determined by the atomic nucleus (usually the hydrogen atomic nucleus) of the biological tissue to be observed and the magnetic field strength. The coil element 52 is, for example, in a ring shape with a diameter of about 10 cm to 15 cm, or a square shape with a side length of about 10 cm to 15 cm, and is two-dimensionally arranged inside the coil cover 56.

[0049] In FIG. 3, an example in which 24 coil elements 52 are two-dimensionally arranged is shown, but the size, number, and arrangement form of the coil elements 52 are not limited to the example shown in FIG. 3. The number of coil elements 52 in the abdominal receiving coil may be, for example, in the range of 16 to 128.

[0050] A heating element 54 is connected to each of the plurality of coil elements 52. The heating element 54 is an element that generates heat by receiving the energy of the high-frequency magnetic field irradiated from the transmission coil 106. The heating element 54 may be an electric circuit module in which an electric circuit including a plurality of circuit elements is packaged. The heating element 54 may be, for example, a molded product having a generally rectangular parallelepiped outer shape. As an example, the heating element 54 may have a three-dimensional shape in which one side of the square on the bottom surface is about 2 cm to 3 cm and the height (thickness) is about 2 cm. The shape and size of the heating element 54 are not limited to this example and can be in various forms. The heating element 54 is two-dimensionally arranged inside the coil cover 56 corresponding to the arrangement of the coil elements 52.

[0051] The coil cover 56 is a cover that constitutes an exterior body covering the outside of the plurality of coil elements 52 and the plurality of heating elements 54. An electrical component including the plurality of coil elements 52 and the plurality of heating elements 54 is housed inside the coil cover 56 and configured as a blanket-shaped receiving coil unit 10. Note that the plurality of coil elements 52 and the plurality of heating elements 54 may be housed inside the coil cover 56 in a state of being fixed on a film (not shown). The film is a support member that fixes the positional relationship between the coil element 52 and the heating element 54 and suppresses displacement.

[0052] A cable unit (not shown) is connected to the coil cover 56. This cable unit is a unit in which multi-channel cables for obtaining signals from each of the plurality of coil elements 52 are bundled.

[0053] Note that the form of the two-dimensional array of the plurality of heating elements 54 corresponding to each coil element 52 is not limited to the example of the array shown in FIG. 3 and may be appropriately designed.

[0054] FIG. 4 is a plan view schematically showing another example of the arrangement form of the heating element 54. Instead of the arrangement form of the heating element 54 shown in FIG. 3, for example, as shown in FIG. 4, similar to the arrangement pattern of the coil elements 52, the plurality of heating elements 54 may be arranged regularly (periodically) at regular intervals. The arrangement form of the heating element 54 is not limited to an arrangement pattern having spatial periodicity and may be an arrangement pattern having no periodicity.

[0055] FIG. 5 is a circuit diagram showing an example of the heating element 54. In FIG. 5, for convenience of explanation, an example of an extremely simplified circuit is shown. The heating element 54 includes, for example, a resonance circuit, so-called a decoupling circuit, for removing the coupling between the coil element 52 and the transmission coil 106 (irradiation coil). As shown in FIG. 5, each of the diode, inductor, and capacitor used in the resonance circuit corresponds to a circuit element that generates heat upon receiving RF irradiation energy.

[0056] FIG. 6 is a schematic cross-sectional view of the receiving coil unit 10. In FIG. 6, a cross-sectional view of the receiving coil unit 10 in a state of being attached to the abdomen of the subject 100 for MRI imaging is shown. The receiving coil unit 10 is located at a position where the heating element 54 is disposed inside the surface of the coil cover 56 that contacts the subject 100 (hereinafter referred to as the subject contact side surface 57), that is, at a position overlapping the region of the internal heating element 54 as viewed from the subject 100 side. In other words, when viewed from the heating element 54 side, the cushioning material 58 is disposed at a position overlapping the region of the heating element 54 in plan view under the heating element 54.

[0057] For each region of the plurality of heating elements 54 disposed inside the coil cover 56, it is preferable that the cushioning material 58 is always disposed at a position overlapping that region. For one region of the heating element 54, one or more, more preferably a plurality of, cushioning materials 58 are disposed at a position overlapping this region. The cushioning material 58 may be disposed only in the vicinity of the region of the heating element 54, and the cushioning material 58 may not be disposed in a region separated from the region of the heating element 54 by a predetermined distance or more.

[0058] The cushioning material 58 may be distributed and disposed at a position overlapping the assumed region in anticipation of the range of displacement of the heating element 54 within the coil cover 56 so that the cushioning material 58 exists at a position overlapping the region of the heating element 54 even if the position of the heating element 54 inside the coil cover 56 deviates slightly from the reference position. The displacement (position error) of the position of the heating element 54 with respect to the reference position may be, for example, within 2 cm.

[0059] The cushioning material 58 has a convex shape facing the subject 100, and the convex shape of the cushioning material 58 and the arrangement pattern of the plurality of cushioning materials 58 make the subject contact side surface 57 of the coil cover 56 have an uneven shape. That is, a concave portion is formed between the cushioning materials 58 that are convex portions, and in a state where the receiving coil unit 10 is attached to the subject 100, this concave portion serves as a passage for air (ventilation path).

[0060] The recesses between adjacent buffer materials 58 of the plurality of buffer materials 58 disposed at positions overlapping the region of the same heating element 54, and the recesses in the buffer material non-disposed region that is separated from the region of the heating element 54 by a certain distance or more each function as a ventilation path, and heat can be released by the air flowing through these recesses.

[0061] The thickness of the buffer material 58 can be designed as appropriate. However, if the coil element 52 is too far from the subject 100 when the receiving coil unit 10 is attached to the subject 100, the sensitivity of signal detection will decrease. Therefore, it is desirable not to make the buffer material 58 into a structure that is larger than necessary. From this perspective, the thickness of the buffer material 58 is preferably 5 mm or less. Note that the thickness of the buffer material 58 may be the maximum height of the convex portions in the uneven shape of the surface 57 of the coil cover 56 on the side contacting the subject. If the buffer material 58 has a thickness of approximately 5 mm, it is possible to form a ventilation path for releasing heat while ensuring the required signal detection sensitivity.

[0062] [Examples of the material and arrangement form of the buffer material] The buffer material 58 is preferably made of a material and / or structure that makes it difficult to transfer the heat of the heating element 54 to the subject 100. The buffer material 58 is preferably configured using a material that is difficult to deteriorate and deform at the temperature of the heat generated from the heating element 54.

[0063] FIG. 7 is a perspective view showing an example of the buffer material 58. The buffer material 58 may be, for example, a foamed buffer material with granular air bubbles encapsulated inside, such as an air cap. In this case, the buffer material 58 may be configured using a material containing, for example, polyethylene.

[0064] FIG. 8 is an enlarged cross-sectional view of the receiving coil unit 10. FIG. 9 is a view (view A arrow view) showing an example of the arrangement of the buffer material 58 as viewed from the direction of arrow A in FIG. 8. In FIG. 9, the illustration of the coil cover 56 and the coil element 52 is omitted in order to clearly show the positional relationship between the buffer material 58 and the heating element 54. The same applies to FIGS. 10 and 11. FIG. 8 shows a cross-section along line 8-8 in FIG. 9.

[0065] As shown in FIG. 8, inside the coil cover 56, an antenna pattern in which coil elements 52 are arranged and a heating element 54 are disposed. A cushioning material 58 is disposed on the surface 57 of the coil cover 56 on the subject contact side between the heating element 54 and the subject 100. FIG. 8 shows an example of the cushioning material 58 in which air bubbles 59 are enclosed.

[0066] The cushioning material 58 has both a heat insulation function of suppressing heat transfer between the heating element 54 and the subject 100 and a function as a member forming a ventilation path for releasing heat. By providing the cushioning material 58 on the surface 57 on the subject contact side, heat generated from the heating element 54 is difficult to be transmitted to the subject 100, and heat can be released from the ventilation path formed between the coil cover 56 and the subject 100.

[0067] The cushioning material 58 may have a structure in which each convex shape is isolated (separated), or a structure in which a plurality of cushioning materials 58 having convex shapes are fixed on a base material in an appropriate arrangement pattern. The cushioning material 58 may be fixed to the coil cover 56 by a structure attached to the surface 57 of the coil cover 56 on the subject contact side. As a structure for attaching the cushioning material 58, for example, a configuration using double-sided tape, an adhesive, or a hook-and-loop fastener may be adopted. The cushioning material 58 that contacts the subject 100 may be consumed with long-term use. By adopting a structure in which the cushioning material 58 is detachably attached to the coil cover 56, the consumed cushioning material 58 can be separated from the coil cover 56 and replaced with a new cushioning material 58.

[0068] Alternatively, the cushioning material 58 on the surface 57 on the subject contact side may have a structure integrated with the coil cover 56. That is, it is configured as a structure in which the coil cover 56 and the cushioning material 58 are integrally formed inseparably or with difficulty in separation, and when the cushioning material 58 is consumed, the entire coil cover 56 integrated with the cushioning material 58 may be replaced with a new coil cover.

[0069] The buffer material 58 is arranged, for example, at a position overlapping with the region of the heating element 54 as viewed from the subject 100 side as shown in FIG. 9. When the region of the heating element 54 is a rectangular region as shown in FIG. 9, the buffer materials 58 may be arranged, for example, one each at the four corners and the center (center) of the rectangular region. In FIG. 9, an example is shown in which five buffer materials 58 are arranged separately from each other with respect to the region of one heating element 54, but the number and arrangement form of the buffer materials 58 arranged at a position overlapping with the region of one heating element 54 are not limited to the example of FIG. 9. One or more, preferably a plurality of buffer materials 58 are arranged at a position overlapping with the region of one heating element 54 in a plan view. The distance between the buffer materials 58 may be close to the extent that the buffer materials 58 come into contact with each other. Further, the buffer materials 58 may be arranged so as to be continuously lined up along the sides of the rectangular region of the heating element 54.

[0070] [Other morphological examples of the buffer material] In FIGS. 7 and 8, the buffer material 58 with air bubbles is exemplified, but the configuration of the buffer material 58 is not limited to this example. The buffer material 58 may be configured using a material with a low thermal conductivity, for example, a resin material such as a heat insulating material, in order to make it difficult to transfer the heat of the heating element 54 to the subject 100. As a resin material suitable for the heat insulating material, for example, foamed materials such as expanded polystyrene and expanded urethane can be applied. The buffer material 58 may be a porous body having appropriate hardness and heat insulation properties.

[0071] From the viewpoint of heat transfer suppression, heat insulation by air is ideal, and from the viewpoint of releasing heat, convection can be promoted by creating a passage for air between the subject 100 and the coil cover 56. Therefore, for example, a form in which the buffer material 58 has a hollow structure (see FIG. 10), or a form in which a convex buffer material 58 is formed using a hard resin or the like and a passage for air is created by increasing the interval between the arrangements of the buffer materials 58 (thinning out) (see FIG. 11) may be adopted, and the same effect can be obtained.

[0072] FIG. 10 is an explanatory diagram showing an example of the buffer material 58A with a hollow structure. FIG. 10, similar to FIG. 9, is a diagram showing an example of the arrangement of the buffer material 58A viewed from the direction of arrow A in FIG. 8. Instead of the buffer material 58 shown in FIGS. 7 and 8, a form may be adopted in which a buffer material 58A with a hollow structure having a tunnel-shaped ventilation passage 70 as shown in FIG. 10 is provided.

[0073] The ventilation passage 70, which is a hollow space penetrating the buffer material 58A, serves as a passage for air together with the recesses around the buffer material 58A. Also, since the ventilation passage 70 contains air, the buffer material 58A has a heat insulation effect by the air.

[0074] In the example of FIG. 10, the ventilation passage 70 penetrating the buffer material 58A is a through hole with both longitudinal ends open in FIG. 10. However, for the ventilation passages 70 penetrating each of the plurality of buffer materials 58A, as shown in FIG. 10, the two ends of each ventilation passage 70 may be configured to open in the same direction (the longitudinal direction in FIG. 10), or a configuration in which ventilation passages 70 opening in different directions are mixed may also be possible. Note that, as in FIG. 10, by aligning the directions of the ventilation passages 70, the flow of air in that direction is promoted.

[0075] The buffer material 58A with a hollow structure may be configured using a resin material such as a heat insulating material, or may be configured using a material not classified as a heat insulating material.

[0076] FIG. 11 is an explanatory diagram showing an example of the buffer material 58B in which a heat insulation effect by air and a convection effect of air can be obtained. FIG. 11, similar to FIG. 9, is a diagram showing an example of the arrangement of the buffer material 58B viewed from the direction of arrow A in FIG. 8. Instead of the buffer material 58 shown in FIGS. 7 and 8, a form of the buffer material 58B as shown in FIG. 11 may be adopted.

[0077] The arrangement of the buffer material 58B shown in FIG. 11 is such that, compared with the arrangement of the buffer material 58 shown in FIG. 9, the buffer material 58B is not arranged at the center position of the rectangular region of the heating element 54, and one buffer material 58B is arranged at each of the four corners of the rectangular region. The buffer material 58B may be composed of a resin material such as a heat insulating material, or may be composed of a material not classified as a heat insulating material. The buffer material 58B may be composed of a hard resin or the like.

[0078] Compared with the arrangements of the buffer materials 58 and 58A shown in FIGS. 9 and 10, the arrangement of the buffer material 58B shown in FIG. 11 has the number of buffer materials 58B overlapping the region of the heating element 54 thinned out, and the region of the recess where the buffer material 58B is not arranged in the region of the heating element 54 is large, that is, the ventilation path serving as the passage for air is large. Thus, due to the heat insulating effect of the air contained in the space of this recess, the transfer of heat from the heating element 54 to the subject 100 can be suppressed, and convection can be promoted by the large ventilation path, allowing the heat to escape.

[0079] 〔Other Modifications〕 Each of the plurality of buffer materials 58 is not limited to the same shape, and those with different shapes may be mixed, and those with different heights (thicknesses) of the convex portions may be included.

[0080] 〔Effects According to the Embodiment〕 According to the receiving coil unit 10 according to the embodiment, the following effects can be obtained.

[0081] [1] Due to the buffer materials 58, 58A, or 58B provided on the surface 57 of the coil cover 56 on the subject contact side, the surface 57 on the subject contact side becomes uneven, and the space between the buffer materials 58 (recess) functions as a passage for air. Therefore, due to the heat insulating effect of the air, it is difficult for the heat of the heating element 54 to be transmitted to the subject 100, and the heat generated from the heating element 54 and / or the heat generated from the subject 100 can be escaped from the passage for air between the surface 57 on the subject contact side and the subject 100. Thereby, the heat sensation of the subject 100 during MRI imaging can be suppressed.

[0082] [2] By arranging the buffer materials 58, 58A, or 58B only in the region near the heating element 54 on the subject contact side surface 57, the contact area with the subject 100 becomes smaller compared to the form in which the buffer material is arranged on one surface of the subject contact side surface 57, and it is possible to greatly secure the passage of air, which is a space formed in the non-contact region.

[0083] [3] The buffer materials 58, 58A, or 58B are structured to be attached to the subject contact side surface 57 of the coil cover 56, so that they can be replaced when the buffer materials 58, 58A, or 58B are consumed.

[0084] 〔Others〕 The present invention is not limited to the scope described in the above embodiments and modified examples. The configurations and the like in the embodiments and modified examples can be changed without departing from the gist of the present invention, and can be appropriately combined between the embodiments and modified examples.

Explanation of Reference Numerals

[0085] 10 Receiver Coil Unit 20 MRI Apparatus 22 Gantry 24 Bore 30 Bed Apparatus 32 Table 34 Top Plate 52 Coil Element 54 Heating Element 56 Coil Cover 57 Subject Contact Side Surface 58, 58A, 58B Buffer Material 59 Air Bubble 70 Ventilation Path 100 Subject 102 Static Magnetic Field Generating Magnet 104 Gradient Magnetic Field Coil 106 Transmission Coil 108 Sequencer 110 High Frequency Magnetic Field Generator 112 Gradient Magnetic Field Power Supply 114 Receiver 116 Control Unit 118 Operation Unit

Claims

1. A coil element that receives a signal generated from a subject, a heating element connected to the coil element, a coil cover that covers the outside of the coil element and the heating element, a plurality of buffer materials that are arranged at positions overlapping the region of the heating element when viewed from the subject side on the surface of the coil cover that contacts the subject, and have a convex shape toward the subject side, A receiving coil unit comprising:

2. The thickness of the buffer material is 5 mm or less, The receiving coil unit according to claim 1.

3. The buffer material is fixed by a structure that adheres to the surface of the coil cover, The receiving coil unit according to claim 1.

4. The buffer material is integrally formed with the coil cover, The receiving coil unit according to claim 1.

5. Including a plurality of the coil elements and a plurality of the heating elements, The buffer material is arranged at a position overlapping each region of the plurality of heating elements when viewed from the subject side on the surface of the coil cover, The receiving coil unit according to claim 1.

6. The coil cover is a flexible bag-shaped cover that can be deformed according to the physique of the subject, The receiving coil unit according to claim 1.

7. The buffer material contains air bubbles, The receiving coil unit according to claim 1.

8. The buffer material has a hollow structure, The receiving coil unit according to claim 1.

9. The buffer material is configured using a heat insulating material, The receiving coil unit according to claim 1.

10. The buffer material is not arranged at the center position of the region of the heating element on the surface of the coil cover, The receiving coil unit according to claim 1.

11. The buffer material is not arranged in a region that is a predetermined distance or more away from the region of the heating element on the surface of the coil cover, The receiving coil unit according to claim 1.

12. The signal received by the coil element is a nuclear magnetic resonance signal, The receiving coil unit according to claim 1.

13. The heating element includes at least one of an inductor, a capacitor, and a diode. The receiving coil unit according to claim 1.

14. The heating element includes a resonance circuit for removing the coupling between a transmission coil that irradiates the subject with a high-frequency magnetic field and the coil element, The receiving coil unit according to claim 1.

15. A nuclear magnetic resonance imaging apparatus comprising the receiving coil unit according to any one of claims 1 to 14, and generating a magnetic resonance image from a nuclear magnetic resonance signal received using the receiving coil unit.

Images