JP5550212B2 - RF coil and MRI apparatus - Google Patents

Description

  The present invention relates to an MRI (Magnetic Resonance Imaging) apparatus, and a high-frequency coil apparatus (RF coil) connected to the MRI apparatus and receiving a magnetic resonance signal generated from a subject, and more particularly to a plurality of elements (elements) The present invention relates to decoupling of a high-frequency coil device in which coils are arranged.

  Conventionally, a plurality of elements are arranged in a desired region of an object to be imaged, a magnetic resonance signal from the object is detected through the plurality of elements, and each detected magnetic resonance signal is imaged. After processing and generating a plurality of series of image data, pixel data corresponding to the same spatial position (single complex signal or one-dimensional complex signal = spectrum signal) is converted into the distribution of the high-frequency magnetic field generated by each element. It is known that a high S / N image can be obtained by creating data for each pixel by multiplying and adding a weighting function determined in advance based on the result and synthesizing one image of a desired region.

  In such a method, the magnetic resonance signals are simultaneously observed by a plurality of elements within the time required to obtain one image, so that the elements do not constantly interfere with each other, that is, one element is predetermined. It is necessary to prevent (decouple) the coils from mutual coupling so that no high-frequency current flows through other elements even when a high-frequency current having a frequency of.

  Conventionally, two elements arranged in a predetermined arrangement plane are overlapped in the arrangement plane by an area determined by the area surrounded by the coil, so that the other of the magnetic fields generated when a current flows through one element. A technique has been proposed in which decoupling is performed in such a state that the sum of the magnetic fields interlinked with these elements becomes zero (see, for example, Patent Document 1).

  On the other hand, a high-frequency coil apparatus that is connected to an MRI apparatus and receives a magnetic resonance signal generated from a subject is generally heavy. For this reason, conventionally, there has been proposed a method of dividing / connecting between two adjacent elements (for example, see Patent Document 2).

U.S. Pat. No. 4,825,162 JP 2006-14823 A

  However, in the decoupling method proposed in Patent Document 1, it is necessary to superimpose two elements in the arrangement plane at the division / connection portion of the case. Therefore, for example, the unsolved problem that the shape of the case of the part to be overlapped must be designed to be thin, and because it is necessary to overlap, the case cannot be divided on the plane orthogonal to the element alignment direction, and the case is divided / connected. There was an unsolved problem that the portion was uneven.

The present invention has been made to solve the above-described problems caused by the prior art, and an object thereof is to provide an RF coil and an MRI apparatus that can perform decoupling between two element coils that are not adjacent to each other .

In order to solve the above-described problems and achieve the object, according to the present invention, a plurality of element coils that receive magnetic resonance signals from a subject are arranged in each of the first and second units that can be connected / separated. in RF coils, a first element coils of the two element coils not adjacent may be disposed on the first unit, the first of the main loop, which is connected in series to the first main loop A second element coil of the two element coils is disposed in the second unit, and is connected in series to the second main loop and the second main loop. A second sub-loop, and a third element coil of the plurality of element coils is adjacent to each of the first and second element coils, and the first unit and the second element coil With the unit connected, Connector constitutes a third of the main loop through the first and second element coils have line decoupling between the two element coils using the first and second sub-loop, wherein The first and third element coils and the second and third element coils are decoupled between the two element coils by providing overlapping portions, respectively, and the second sub-loop is the first sub-loop. The first sub-loop and the winding direction are opposite to each other in the connecting / separating portion .

In addition, the present invention applies a static magnetic field to a subject and applies a gradient magnetic field to a subject, a first unit and a second unit that can be connected / separated, and the static magnetic field and the gradient magnetic field. And a plurality of element coils that receive magnetic resonance signals from the subject to which is applied, a first element coil of two element coils that are not adjacent to each other is disposed in the first unit, and comprises a main loop, and the first sub-loop connected in series with the first of the main loop, the second coil elements of said two element coils is disposed in the second unit, A third element having a second main loop and a second sub-loop connected in series to the second main loop and adjacent to each of the first element coil and the second element coil A coil and the first unit; In a state where the serial second unit is connected, it is connected via the electrical connector forms a loop, the first and second element coils, two with the first and second sub-loops There line decoupling between the element coils, the first and third coil elements and said second and third element coils of the performs decoupling between the two element coils by providing a superposed portion respectively The second sub-loop is opposed to the first sub-loop in the connectable / separable portion, and the winding direction of the first sub-loop is opposite to that of the first sub-loop .

According to the present invention, it is possible to perform decoupling between two element coils that are not adjacent to each other.

Further, according to the present invention, the shape of the divided / connected portion of the case of the coil device can be simplified, thereby increasing the strength of the divided / connected portion, improving the design, and further reducing the cost. Can be planned.

  Exemplary embodiments of an RF coil and an MRI apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a system configuration diagram of an MRI apparatus according to a first embodiment of the present invention. The MRI apparatus 100 includes a static magnetic field magnet 11, a gradient magnetic field coil 13, a gradient magnetic field power supply 15, a high frequency coil 17, a transmission unit 19, a helmet type head coil device 21, and a reception unit 25.

  The cylindrical static magnetic field magnet 11 generates a uniform static magnetic field in the internal space. For example, a permanent magnet or a superconducting magnet is used as the static magnetic field magnet 11. A cylindrical gradient coil 13 is disposed inside the static magnetic field magnet 11. The gradient coil 13 is configured by combining three coils corresponding to the X, Y, and Z axes orthogonal to each other. The three coils are individually supplied with electric current from the gradient magnetic field power supply 15 and generate gradient magnetic fields in which the magnetic field strength is inclined along the X, Y, and Z axes. The Z-axis direction is the same direction as the static magnetic field.

  A cylindrical high frequency coil 17 is disposed inside the gradient magnetic field coil 13. A subject P placed on the top plate 51 is inserted inside the high-frequency coil 17. The high frequency coil 17 is supplied with a high frequency pulse from the transmitter 19 and generates a high frequency magnetic field. The high frequency coil 17 receives a magnetic resonance signal radiated from the subject P due to the influence of the high frequency magnetic field.

  The transmission unit 19 includes an oscillation unit, a phase selection unit, a frequency conversion unit, an amplitude modulation unit, and a high frequency power amplification unit. The oscillation unit generates a high-frequency signal having a resonance frequency unique to the target nucleus in the static magnetic field. The phase selection unit selects the phase of the high frequency signal. The frequency modulation unit modulates the frequency of the high-frequency signal output from the phase selection unit. The amplitude modulation unit modulates the amplitude of the high-frequency signal output from the frequency modulation unit, for example, according to a sync function. The high frequency power amplification unit amplifies the high frequency signal output from the amplitude modulation unit. As a result of the operation of each of these units, the transmission unit 19 transmits a high frequency pulse corresponding to the Larmor frequency to the high frequency coil 17.

  A helmet-type head coil device (hereinafter simply referred to as a head coil device) 21 is arranged so as to cover the entire head of the subject P. The head coil device 21 incorporates eight elements (not shown) formed of loop coils. The element incorporated in the head coil device 21 receives a magnetic resonance signal radiated from the subject P.

  The receiving unit 25 includes a selector, a pre-stage amplifier, a phase detector, and an analog / digital converter. The selector selectively inputs magnetic resonance signals output from the high frequency coil 17 and the head coil device 21. The receiving unit 25 amplifies the magnetic resonance signal output from the selector. The phase detector detects the phase of the magnetic resonance signal output from the preamplifier. The analog-digital converter converts the signal output from the phase detector into a digital signal.

  The operator console unit 20 includes an interface unit 31, a data collection unit 33, a reconstruction unit 35, a storage unit 37, a display unit 39, an input unit 41, and a control unit 43.

  The interface unit 31 is connected to the gradient magnetic field power supply 15, the transmission unit 19, and the reception unit 25. The interface unit 31 inputs and outputs signals exchanged between these connected units and the operator console unit 20.

  The data collection unit 33 collects digital signals output from the reception unit 25 via the interface unit 31. The data collection unit 33 stores the collected digital signal, that is, magnetic resonance signal data in the storage unit 37. The reconstruction unit 35 performs post-processing, that is, reconstruction such as Fourier transform, on the magnetic resonance signal data stored in the storage unit 37, and obtains spectrum data or image data of the desired nuclear spin in the subject P. Ask.

  The storage unit 37 stores magnetic resonance signal data and spectrum data or image data for each subject P. The display unit 39 displays various information such as spectrum data or image data under the control of the control unit 43. As the display unit 39, a display device such as a liquid crystal display can be used. The input unit 41 receives various commands and information input from an engineer. The control unit 43 controls these parts collectively to control the imaging operation of the MRI apparatus main body.

  In the MRI apparatus 100 having such a configuration, the receiving unit 25 receives the magnetic resonance signals output from the high-frequency coil 17 and the head coil apparatus 21 and generates magnetic resonance signal data. And the control part 43 images the whole subject P based on the magnetic resonance signal data by the high frequency coil 17, for example. Further, the control unit 43 performs local imaging of the head of the subject P based on the magnetic resonance signal data from the head coil device 21.

  FIG. 2 is an enlarged side view showing the head coil device 21 of FIG. FIG. 3 is a side view showing a state in which the head coil device 21 is opened. The head coil device 21 can be divided into an upper coil device 21 </ b> A and a lower coil device 21 </ b> B in order to facilitate attachment and detachment with respect to the subject P.

  FIG. 4 is a side view showing the arrangement of the eight elements built in the head coil device 21. FIG. 5 is a front view of the same. The head coil device 21 has eight elements E1 to E8 provided in the case. The eight elements E1 to E8 are arranged in alignment along the head surface of the subject P so as to go around the head. That is, the eight elements E1 to E8 are arranged in a line in the alignment direction on the curved surface (array plane) surrounding the head of the subject P over the entire circumference.

  Of the eight elements E1 to E8, five elements E1 to E5 are arranged in the upper coil device 21A. The remaining three elements E6 to E8 are disposed in the lower coil device 21B. That is, the head coil device 21 is divided between the adjacent elements E1 and E8 and between the adjacent elements E5 and E6. The case of the head coil device 21 is divided at a position between the elements E1 and E8 and between the elements E5 and E6 by a plane orthogonal to the alignment direction.

  FIG. 6 is a perspective view showing the details of two elements adjacent to each other at the division / connection portion of the case. In FIG. 6, the elements E1 and E5 are described as the first element 1, and the elements E8 and E6 are described as the second element 2. For convenience of explanation, it is assumed that the first element 1 and the second element 2 are formed as circuit patterns on a flat rectangular parallelepiped substrate 60 and a substrate 61, respectively.

  The first element 1 is composed of a single circuit pattern that forms a loop on the substrate 60 (only the end on the connection / division side is shown in the figure). The first element 1 is formed on the main surface (upper surface, large area surface) 60a of the substrate 60 and extends to the end portion of the substrate 60, and the end surface 60b of the substrate 60 extends from the main loop portion 1a. And a sub-loop portion 1c (first counter electromotive force induction portion) formed so as to be bent. The main loop portion 1a is formed as two parallel patterns. The sub-loop portion 1c is formed as a substantially U-shaped pattern that connects both ends to the two patterns.

  The second element 2 is composed of one circuit pattern that forms a loop on the substrate 61 (only the end on the connection / division side is shown in the figure). The second element 2 includes a main loop portion 2a formed on the main surface 61a of the substrate 61, an intersecting portion 2b formed at a portion closest to the end on the main surface 61a of the substrate 61, and the intersecting portion 2b. To the sub-loop portion 2c (second counter electromotive force induction portion) formed so as to be bent along the end surface 61b of the substrate 61. The main loop portion 2a is formed as two parallel patterns provided on the main surface 61a. The intersecting portion 2b is formed as a substantially X-shaped pattern extending from the two parallel patterns by bending in the center direction and extending to the vicinity of the opposite pattern after intersecting at the center portion. The sub-loop portion 2c is formed as a substantially U-shaped pattern that connects both ends to the intersecting portion 2b.

  In the intersecting portion 2b, an insulator is sandwiched at the time of manufacture, and the two patterns are insulated and exposed. The first element 1 and the second element 2 configured as described above are arranged so that the sub-loop portion 1c and the sub-loop portion 2c face each other such that the U-shaped portions overlap each other. And the case accommodated with the 1st element 1 and the 2nd element 2 is divided | segmented in the surface orthogonal to an alignment direction between the subloop part 1c and the subloop part 2c.

  FIG. 7 is a perspective view for explaining that the first element 1 and the second element 2 are decoupled. The sub-loop portion 1c of the first element 1 and the sub-loop portion 2c of the second element 2 are arranged such that the magnetic flux interlinking from one sub-loop portion into the other sub-loop portion is directed in the alignment direction. In addition, an induced electromotive force generated by the magnetic flux in the other sub-loop portion and an induced electromotive force generated in the other main loop portion by the magnetic flux interlinking from the one main loop portion into the other main loop portion. Are provided in opposite directions and the same size.

That is, for example, when a current A ₁ flows through the first element 1, the magnetic flux B ₂ interlinking from the plane surrounded by the sub-loop portion 1 c to the plane surrounded by the sub-loop portion 2 c is the element. The direction is aligned. The magnetic flux B ₂ is caused to flow by the induced electromotive force generated in the sub-loop portion 2c by the current A ₂₂ and the magnetic flux B ₁ linked from the main loop portion 1a to the main loop portion 2a. The current A ₂₁ that is about to flow to the main loop portion 2a by the induced electromotive force generated in the loop portion 2a is provided so as to have the same magnitude in opposite directions. Since the magnitude of the magnetic flux B ₂ is determined by the area surrounded by the sub-loop portion 1c and the area surrounded by the sub-loop portion 2c, it is possible to easily achieve such a relationship by adjusting both areas. .

  Note that the sub-loop portion 1c and the sub-loop portion 2c do not have to be strictly in the above-described relationship, that is, the sub-loop portion 1c and the sub-loop portion 2c need only have the above-described relationship. However, it is only necessary to adjust so that the total sum of the magnetic fields interlinked with the other coil among the magnetic fields generated when a current flows through one coil is zero in the entire coil.

  According to the MRI apparatus of the present embodiment, the first main loop portion 1a parallel to the arrangement plane and the second main element 2 side of the first main loop portion 1a are provided so as to be substantially orthogonal to the arrangement plane. A first element 1 having a first sub-loop portion 1c (first counter electromotive force inducing portion), a second main loop portion 2a parallel to the arrangement plane, and a first of the second main loop portion 2a The second sub-loop portion 2c (second counter electromotive force inducing portion) provided to face the first sub loop portion 1c (first counter electromotive force inducing portion) on the element 1 side of Since the second element 2 is provided, the first element 1 and the second element 2 can be decoupled without overlapping in the arrangement plane. Therefore, by dividing between these two coils, the shape of the divided / connected portion of the coil device can be simplified. In addition, this can increase the strength of the divided / connected portions, improve the design, and further reduce the cost.

  In addition, according to the present embodiment, the counter electromotive force induction unit that induces an electromotive force that cancels so that the sum of the magnetic fields interlinked with the other coil becomes 0 is the sub-loop part 1c, Since it is comprised by 2c, the area of a cancellation | release counter electromotive force induction part can be ensured effectively, and the magnitude | size of a division | segmentation / connection part is not enlarged unnecessarily. In addition, by forming the U-shape, the area can be easily calculated and adjusted.

  The first element 1 and the second element 2 of the present embodiment are applied to a divided portion of the helmet-type head coil device 21, but a plurality of elements are arranged in a predetermined position. Other coil devices (lower limb coil device, foot coil, etc.) can also be applied as long as the coil device is divided and connected at.

  In the present embodiment, the first element 1 and the second element 2 have been described as being formed in circuit patterns on the flat rectangular parallelepiped substrate 60 and the substrate 61, respectively, for convenience of explanation. However, the present invention is not limited to this, and the first element 1 and the second element 2 may be formed by winding a conductor such as a copper wire around a bobbin. The plate to be formed may be formed by being affixed to the substrate, or may be formed in any way.

  In addition, although the intersection part 2b of a present Example is provided in the outermost end part of the main surface 61a of the board | substrate 61, you may provide in the uppermost part (side nearest to the main surface) of the end surface 61b.

  FIG. 8 is a perspective view for explaining the shape of the division / connection portion of the coil device according to the second embodiment of the present invention. In FIG. 8, the first element 3 is composed of one circuit pattern forming a loop, a main loop portion 3a formed as two parallel patterns, and a second element 4 of the main loop portion 3a. A sub-loop part 3c (first counter electromotive force induction part) formed so as to be bent from the main loop part 3a is formed on the side. The sub-loop portion 3c is formed as a substantially arc-shaped pattern that connects both ends to the two patterns of the main loop portion 3a.

  The second element 4 is composed of one circuit pattern that forms a loop, and is formed on the main loop portion 4a formed as two parallel patterns and on the first element 4 side of the main loop portion 4a. The crossing portion 4b and the sub-loop portion 4c (second counter electromotive force induction portion) formed so as to be bent from the crossing portion 4b are configured. The sub-loop portion 4c is formed as a substantially arc-shaped pattern that connects both ends to the intersecting portion 2b.

  The 1st element 3 and the 2nd element 4 are arrange | positioned so that the subloop part 3c and the subloop part 4c may be opposed so that a mutual arc-shaped part may overlap. And the 1st element 3 and the 2nd element 4 are made so that the sum total of the magnetic field linked to the other coil among the magnetic fields generated when current flows through one coil becomes zero. .

  In the first element 3 and the second element 4 of the present embodiment, the same operation as that of the first embodiment can be performed to obtain substantially the same effect.

  FIG. 9 is a perspective view for explaining the shape of the division / connection portion of the coil device according to the third embodiment of the present invention. In FIG. 9, the first element 5 is composed of one circuit pattern forming a loop, a main loop portion 5a formed as two parallel patterns, and a second element 6 of the main loop portion 5a. A winding part 5b (first counter electromotive force induction part) formed by being wound a plurality of times in the shape of a solenoid coil in the central side is configured.

  The winding portion 5b is formed on the arrangement plane after a pattern folded from one end of the main loop portion 5a (on the front side in FIG. 9) to the center side extends to the opposite side beyond the center portion. Folded so as to be orthogonal to the second element 6, and then extended in the direction of the second element 6 while spirally turning in a counterclockwise direction toward the second element 6, and then returned to the arrangement plane, and again passed through the center portion to the other element It is formed so as to be connected to the main loop portion 5a.

  The second element 6 is composed of one circuit pattern that forms a loop. The main loop portion 6a formed as two parallel patterns, and the central portion of the main loop portion 6a on the first element 5 side. A winding portion 6b (second counter electromotive force induction portion) formed by being wound a plurality of times in a solenoid coil shape is configured.

  The winding part 6b is folded so that the pattern folded from one end of the main loop part 6a (on the front side in FIG. 9) formed on the arrangement plane to the center side does not cross the center part and is orthogonal to the arrangement plane. Then, it extends in the direction of the first element 5 while spirally turning counterclockwise toward the first element 5, and then returns to the arrangement plane, and then connects to the other main loop portion 6a. Is formed.

The first element 5 and the second element 6 are disposed so as to face each other so that the solenoid coil-shaped portions of the mutual winding portions 5b and 6b coincide with the central axis. For example, when the current A ₁ flows through the first element 5, the magnetic flux B ₂ interlinking from the winding part 5 b into the winding part 6 b is made to face the coil alignment direction. The current A ₂₂ that is about to flow to the winding portion 6b by the induced electromotive force generated by B ₂ in the winding portion 6b, and the magnetic flux B _{1 that} is linked from the main loop portion 5a to the main loop portion 6a are supplied to the main loop portion 6a. The current A ₂₁ that is about to flow to the main loop portion 6 a by the induced electromotive force to be generated is provided in the opposite direction to have the same magnitude. Since the magnitude of the magnetic flux B ₂ is determined by the area surrounded by the winding portions 5b and 6b and the number of turns, the relationship can be easily obtained by adjusting the number of turns.

  As described in the first embodiment, the winding portion 5b and the winding portion 6b do not have to be strictly in the above relationship, and the first element 5 and the second element 6 are the entire coil. In this case, it is only necessary that the sum of the magnetic fields interlinked with the other coil among the magnetic fields generated when a current flows through one coil is zero.

  According to the present embodiment, the effect substantially similar to that of the first embodiment can be obtained, and the counter electromotive force inducing section for inducing the counter electromotive force is configured by the solenoid coil-shaped winding sections 5b and 6b. Since the size of the electromotive force can be ensured by the number of turns, the size of the case of the division / connection portion can be further reduced. Moreover, it can adjust easily by changing the number of turns.

  FIG. 10 is a perspective view for explaining the shape of the dividing / connecting portion of the coil device according to the fourth embodiment of the present invention. In FIG. 10, the first element 7 has two main loop portions 7 a formed as parallel patterns and a winding formed by being wound in a solenoid coil shape, as in the third embodiment. Although the part 7b (first counter electromotive force inducing part) is included, the winding part 7b is formed with one turn.

  Similarly to the third embodiment, the second element 8 also has two main loop portions 8a formed as parallel patterns, and a winding portion 8b (a first winding portion formed by winding in a solenoid coil shape). 2), the winding portion 8b is formed with one winding.

  The first element 7 and the second element 8 of the present embodiment can perform substantially the same operation as that of the third embodiment, and can obtain substantially the same effect.

  By the way, in the said Examples 1-4, although the decoupling of two adjacent elements was demonstrated, when using many coils, it is necessary to decouple also about two elements which are not adjacent. In the fifth embodiment, therefore, decoupling of elements that are not adjacent to each other will be described.

  FIG. 11A is a side view of a head coil device different from the head coil device shown in the first embodiment. The head coil device 71 can be divided into an upper coil device 71A and a lower coil device 71B. The element 72 is adjacent to the element 73, and both are decoupled by providing an overlapping portion. The element 73 is also adjacent to the element 74, and both are decoupled by providing an overlapping portion. The element 73 forms a loop by connecting the upper portion 73A and the lower portion 73B at two locations by the electrical connector 75 when the head coil device 71 is closed.

  The element 72 has a decoupling main loop portion 72a and a decoupling sub loop portion 72b, and the element 74 has a decoupling main loop portion 74a and a decoupling sub loop portion 74b. As shown in FIG. 11B, the decoupling sub-loop portion 72b is provided so as to intersect with the decoupling main loop portion 72a, and is provided to face the decoupling sub-loop portion 74b. Thus, the decoupling of the non-adjacent element 72 and element 74 can be performed by making the decoupling sub-loop part 72b and the decoupling sub-loop part 74b face each other.

  However, the decoupling sub-loop portion 72b and the decoupling sub-loop portion 74b must face each other so as not to shift. Therefore, here, the guide pin 76 is provided in the upper coil device 71A, and the guide pin 76 is inserted into the hole 77 provided in the lower coil device 71B so that the decoupling sub-loop portion 72b and the decoupling sub-loop portion 74b The opposing positional relationship is maintained.

  As a means for maintaining the opposing positional relationship between the decoupling sub-loop portion 72b and the decoupling sub-loop portion 74b, a lock mechanism as shown in FIG. 11C is used as an upper coil device 71A and a lower coil device 71B. It can also be provided between. Here, the decoupling of the non-adjacent element 72 and the element 74 is performed by making the decoupling sub-loop part 72b and the decoupling sub-loop part 74b face each other, but the decoupling sub-loop part 72b Further, the decoupling can also be performed by superimposing a part of the decoupling main loop portion 72a and a part of the decoupling main loop portion 74a without providing the decoupling sub loop portion 74b.

  FIG. 12 is a diagram showing a part of a whole body coil device composed of a plurality of units. Each unit has a plurality of elements, and decoupling is performed by overlapping a part between adjacent elements 82 and 83 of the unit 81A. Further, decoupling is performed by overlapping a part between the element 83 of the unit 81A and the element 84 of the unit 81B. In the case of the whole body coil device, the unit 81A and the unit 81B are not always connected and used depending on the imaging location of the patient. Therefore, an element in which a loop is formed by the connection of the unit 81A and the unit 81B is not used. Absent.

  In addition, the element 82 of the unit 81A includes a decoupling loop portion 82A, and the decoupling loop portion 82A is partially overlapped with the element 84 of the unit 81B, thereby decoupling between the non-adjacent element 82 and the element 84. Is done. Here, the decoupling loop portion 82A is partially overlapped with the element 84 of the unit 81B. However, as shown in FIG. 11, a decoupling main loop portion and sub-loop portion are provided for each element. Decoupling can also be performed by providing one sub-loop portion so as to intersect with the main loop portion and arranging the sub-loop portion to face each other.

  FIG. 13 is a diagram showing another example of decoupling between non-adjacent elements in a whole body coil device composed of a plurality of units. Also in this example, decoupling is performed by overlapping a part between adjacent elements. On the other hand, between non-adjacent elements, each element is provided with a decoupling loop portion, and decoupling is performed by overlapping the decoupling loop portions. For example, the element 91 has a decoupling loop portion 91 a, and the decoupling between the element 91 and the element 93 is performed by partially overlapping the decoupling loop portion 93 a of the element 93. Here, the decoupling loop portions are partially overlapped with each other. However, as shown in FIG. 11, each element has a decoupling main loop portion and a sub-loop portion as one sub-loop portion. Decoupling can also be performed by providing it so as to cross the main loop portion and arranging the sub-loop portion so as to face each other.

  FIG. 14 is a diagram showing a part of another coil device composed of a plurality of elements. Also in this example, decoupling is performed by overlapping a part between adjacent elements. For example, the decoupling between the adjacent element 96 and the element 97 and the decoupling between the adjacent element 97 and the element 98 are performed by overlapping a part. On the other hand, between non-adjacent elements, each element is provided with a decoupling loop portion, and decoupling is performed by overlapping the decoupling loop portions. For example, the elements 96 and 98 have decoupling loop portions 96a and 98a, respectively, and decoupling between the element 96 and the element 98 is performed by overlapping a part of the decoupling loop portions 96a and 98a. . Here, the decoupling loop portions are partially overlapped with each other. However, as shown in FIG. 11, each element has a decoupling main loop portion and a sub-loop portion as one sub-loop portion. Decoupling can also be performed by providing it so as to cross the main loop portion and arranging the sub-loop portion so as to face each other.

  Further effects and modifications can be easily derived by those skilled in the art. Accordingly, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

  The present invention is suitable for application to a high-frequency coil device in which a plurality of elements are arranged, and in particular, division / connection is performed between two adjacent elements, and decoupling is required between both elements. It is optimal to be applied to a high-frequency coil device and a high-frequency coil device that requires decoupling between two non-adjacent elements.

1 is a system configuration diagram of an MRI apparatus according to a first embodiment of the present invention. It is a side view which expands and shows the head coil apparatus of FIG. It is a side view which shows a mode that the head coil apparatus was opened. It is a side view which shows arrangement | positioning of eight elements incorporated in the head coil apparatus. It is a front view which shows arrangement | positioning of eight elements incorporated in the head coil apparatus. It is a perspective view which shows the detail of two elements which adjoin by a division part. It is a perspective view for demonstrating that a 1st element and a 2nd element are decoupled. It is a perspective view for demonstrating the shape of the division | segmentation / connection part of the coil apparatus of Example 2 of this invention. It is a perspective view for demonstrating the shape of the division | segmentation / connection part of the coil apparatus of Example 3 of this invention. It is a perspective view for demonstrating the shape of the division | segmentation / connection part of the coil apparatus of Example 4 of this invention. It is a figure which shows another head coil apparatus. It is a figure which shows a part of whole body coil apparatus comprised from a some unit. It is a figure which shows the other example of decoupling between the elements which are not adjacent in the whole body coil apparatus comprised from a some unit. It is a figure which shows a part of other coil apparatus comprised from a some element.

Explanation of symbols

1, 3, 5, 7 First element 2, 4, 6, 8 Second element 1a, 2a, 3a, 4a, 5a, 6a, 8a Main loop portion 1c, 2c, 3c, 4c Sub loop portion (offset (Electromotive force induction part)
2b, 4b Intersection 5b, 6b, 7b, 8b Winding part (offset electromotive force induction part)
DESCRIPTION OF SYMBOLS 11 Static magnetic field magnet 13 Gradient magnetic field coil 15 Gradient magnetic field power supply 17 High frequency coil 19 Transmission part 20 Operator console part 21 Helmet type head coil apparatus 21A Upper coil apparatus 21B Lower coil apparatus 25 Reception part 31 Interface part 33 Data collection part 35 Reconfiguration Unit 37 Storage unit 39 Display unit 41 Input unit 43 Control unit 51 Top plate 60 Substrate 60a Substrate 60 main surface 60b Substrate 60 end surface 61 Substrate 61a Substrate 61 main surface 61b Substrate 61 end surface 71 Head coil device 71A Upper coil Device 71B Lower coil device 72, 73, 74, 82, 83, 84, 91, 92, 93, 96, 97, 98 Element 72a, 74a Decoupling main loop portion 72b, 74b Decoupling sub loop portion 73A Upper portion 73B Lower part 75 Electric co Kuta 76 the guide pin 77 holes 81A, 81B unit 82A, 91a, 93a, 96a, 98a loop portion 100 MRI apparatus E1~E8 element for decoupling

Claims (8)

In each of the RF coils in which a plurality of element coils that receive magnetic resonance signals from the subject are arranged in the first unit and the second unit that can be connected / separated,
A first element coil of two element coils that are not adjacent to each other is arranged in the first unit, and includes a first main loop and a first sub-loop connected in series to the first main loop. Have
A second element coil of the two element coils is disposed in the second unit and has a second main loop and a second sub-loop connected in series to the second main loop. And
A third element coil of the plurality of element coils is adjacent to each of the first and second element coils, and the electric connector is connected to the first unit and the second unit. Through the third main loop,
The first and second element coils perform decoupling between two element coils using the first and second sub-loops,
Wherein the first and third coil elements and said second and third element coils of the stomach line decoupling between the two element coils by providing a superposed portion, respectively,
The second sub-loop is opposed to the first sub-loop in the connectable / separable portion, and the winding direction of the first sub-loop is opposite .
RF coil. The RF coil according to claim 1 , further comprising a holding portion for holding a positional relationship in which the first and second sub loops face each other. The first sub-loop and the second sub-loop are induced so that the sum of the magnetic fields interlinked with the other element coil out of the magnetic fields generated when a current flows through the one element coil becomes zero. The RF coil according to claim 1 , wherein an electromotive force is generated. The first sub-loop and the second sub-loop include an induced electromotive force generated in one sub-loop by a magnetic flux interlinking from one sub-loop to the other sub-loop, and one main loop. magnetic flux linking the inner to the other within the main loop and the induced electromotive force to be generated in the other of the main loop, RF according to claim 1 for generating the induced electromotive force to be the same size in the opposite directions to each other coil. The first sub-loop is configured by a loop that is bent from an end of the first main loop on the second element coil side in a direction substantially orthogonal to the arrangement plane, and the second sub-loop is the first sub-loop. 2. The RF according to claim 1 , comprising: an intersecting portion provided at an end of the two main loops on the first element coil side; and a loop connected to the intersecting portion and facing the first sub-loop. coil. The RF coil according to claim 1 , wherein the first sub-loop and the second sub-loop form a U-shape. The first sub-loop is configured by a first winding portion provided on the second element coil side of the first main loop with a central axis directed in the alignment direction, and the second sub-loop is said second RF coil according to claim 1, which consists of the second winding portion provided on the extension of the first winding portion of the main loop first element coil of. An application unit that applies a gradient magnetic field while applying a static magnetic field to the subject;
A plurality of element coils disposed in the first unit and the second unit that can be connected / separated, and receiving magnetic resonance signals from the subject to which the static magnetic field and the gradient magnetic field are applied;
A first element coil of two element coils that are not adjacent to each other is arranged in the first unit, and includes a first main loop and a first sub-loop connected in series to the first main loop. Have
A second element coil of the two element coils is disposed in the second unit, and includes a second main loop and a second sub-loop connected in series to the second main loop. Have
A third element coil adjacent to each of the first element coil and the second element coil is connected via an electrical connector in a state where the first unit and the second unit are coupled. Forming a loop,
The first and second element coils perform decoupling between two element coils using the first and second sub-loops,
Wherein the first and third coil elements and said second and third element coils of the stomach line decoupling between the two element coils by providing a superposed portion, respectively,
The second sub-loop is opposed to the first sub-loop in the connectable / separable portion, and the winding direction of the first sub-loop is opposite .
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