JP2008154933A - High-frequency coil and magnetic resonance imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-frequency coil capable of highly accurately and efficiently receiving magnetic resonance signals. <P>SOLUTION: A receiving coil 10 is disposed with a plurality of loop coil units 50<SB>1</SB>-50<SB>4</SB>in a two-dimensional matrix state, and is constituted to superpose parts of the loop coil units adjoining in x-axial and y-axial directions. The adjoining loop coil units are rotatably connected at one parts by connection parts 51<SB>1</SB>-51<SB>4</SB>disposed at central points of the superposed parts. If one loop coil unit out of the connected coil units is rotated around the rotary shaft relative to the other loop coil unit to deform the receiving coil whole body, the area of the superposed parts is scarcely changed, so that a neutral state of the mutual induction generated between the adjoining coils can be retained constantly. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a high-frequency coil for receiving a high-frequency magnetic resonance signal and a magnetic resonance imaging apparatus including the high-frequency coil, and in particular, a plurality of surface coils so that a part of coil surfaces of adjacent surface coils overlap each other. And a magnetic resonance imaging apparatus including the high frequency coil.

  2. Description of the Related Art A magnetic resonance imaging apparatus (Magnetic Resonance Imaging: MRI, hereinafter abbreviated as “MRI apparatus”) includes a receiving high-frequency coil for receiving a high-frequency magnetic resonance signal generated from a subject. In order to receive a weak magnetic resonance signal with high sensitivity, it is necessary to arrange a receiving high-frequency coil in the vicinity of a diagnostic region (region of interest) to be imaged by the subject. Therefore, in the MRI apparatus, it is desirable that the shape of the receiving coil be as close as possible to the body surface shape of the imaging region of the subject. Since the body surface shape of the subject differs for each part to be diagnosed (for example, a shoulder or a head), the MRI apparatus is provided with a dedicated receiving coil having a shape suitable for the shape of the part. .

  As such a receiving high-frequency coil, a coil in which a plurality of surface coils are arranged in an array is often used (see, for example, Patent Document 1). In general, the plurality of surface coils have an overall shape that fits the body surface shape of the imaging region of the subject (that is, the coil surface of each surface coil is orthogonal to the normal direction of the body surface of the subject). Is arranged). By using such a high-frequency coil, magnetic resonance signals emitted from the same diagnostic site can be detected from multiple directions via multiple surface coils, and the detection results can be combined to reconstruct an extremely clear image. Will be able to.

  It is mutual induction between the coils that must be taken into consideration when adopting such a type of coil. This is because the current signal generated in the coil by this mutual induction becomes a noise component for the magnetic resonance signal to be detected. In the high-frequency coil disclosed in Patent Document 1, etc., the coil surfaces of adjacent surface coils are arranged so as to partially overlap in order to reduce noise components caused by mutual induction. If an overlapping portion is provided on the coil surfaces of adjacent coils, the magnetic flux generated by the mutual induction can be canceled by the magnetic flux of the adjacent coil, reducing the current generated by the mutual induction and reducing noise. This is because components can be suppressed.

JP 2006-141444 A

  In the MRI apparatus as described above, a dedicated receiving coil is provided for each diagnostic part, so that it is necessary to replace the receiving coil every time the diagnostic part is changed. Such an exchange operation is very troublesome for an operator (that is, a doctor or a technician) of the MRI apparatus, and there is a disadvantage that the use time of the apparatus is increased by the exchange operation. Further, since it is necessary to provide a large number of receiving coils, there is a disadvantage that the apparatus cost becomes expensive.

  In order to solve these disadvantages, the shape of the receiving coil is made flexible, and when changing the diagnostic part, it is only necessary to change the shape of the receiving coil, and the coil is connected between different diagnostic parts. It is desirable to be able to use it in common. However, in a receiving coil in which a plurality of surface coils are arranged, when the shape of the entire coil is changed, the positional relationship between adjacent surface coils changes relatively, and as the positional relationship changes, the overlapping portion of the coil surface changes. The area will also vary. If the area of the overlapping portion fluctuates, the state of the magnetic field around the surface coil changes, and there is a disadvantage that the above-described noise suppression effect due to magnetic flux cancellation cannot be obtained sufficiently.

  Therefore, an object of the present invention is to provide a high-frequency coil for receiving a high-frequency magnetic resonance signal with high accuracy.

  In order to achieve the above object, the invention described in claim 1 is a high-frequency coil in which a plurality of surface coils are arranged so that a part of coil surfaces of adjacent surface coils overlap each other. Even if the relative positional relationship of is changed, it is a high frequency coil characterized by including the connection part which connects the adjacent surface coil so that the fluctuation | variation of the area of the overlapping part of a coil surface may be in a predetermined range.

  The invention described in claim 6 is a magnetic resonance imaging apparatus including the high-frequency coil according to the present invention.

  According to the first aspect of the present invention, even if the shape of the entire high-frequency coil is changed and the reception sensitivity region of the high-frequency coil is fitted to the diagnostic part, the variation in the area of the overlapping portion of the coil surface is within a predetermined range. Thus, the neutralization state of the mutual induction generated between the adjacent coils can be always kept constant. As a result, even if the overall shape of the high-frequency coil is changed, it is possible to receive a magnetic resonance signal while maintaining a high S / N ratio.

  According to the sixth aspect of the present invention, since the reception sensitivity area of the high frequency coil can be adjusted to a plurality of different diagnostic sites, a high frequency coil that receives magnetic resonance signals from different diagnostic sites is shared. It becomes possible to become. For this reason, the frequency of replacing the high-frequency coil can be reduced for each diagnosis site and for each patient, so that the burden on the operator of the apparatus can be reduced and the overall diagnosis time can be shortened. Become. Further, since it is not necessary to provide a large number of high frequency coils, the apparatus cost is reduced.

  An embodiment of the present invention will be described with reference to FIGS.

FIG. 1 shows an external view of a magnetic resonance signal receiving coil 10 used in a magnetic resonance imaging apparatus (hereinafter abbreviated as “MRI apparatus”) according to the present embodiment. As shown in FIG. 1, the receiving coil 10, four loop coil units 50 _1, 50 _2, 50 _3, 50 _4, and four connecting portions 51 _1, 51 _2, 51 _3, 51 _4, four a substrate case 52 _1, 52 _2, 52 _3, 52 _4, four connection cable 53 _1, 53 _2, 53 _3, and 53 _4, and is configured to include a connector 54.

Each of the loop coil units 50 ₁ to 50 ₄ is an octagonal coil unit having an xy plane as its coil surface. The sizes of the loop coil units 50 ₁ to 50 ₄ are, for example, 15 cm in the x-axis direction and 15 cm in the y-axis direction, and the thickness is about 1 cm.

FIG. 2 shows a cross-sectional view taken along line AA ′ of FIG. 1 (that is, a partial cross-sectional view of the loop coil unit 50 ₁ ). As shown in FIG. 2, the loop coil unit 50 ₁ includes a coil trace substrate 502, insulation reinforcing plates 504 ₁ and 504 ₂ , and exterior covers 506 ₁ and 506 ₂ . The loop coil units 50 ₁ to 50 ₄ are not limited to octagonal shapes, and the shape of the loop coil units 50 ₁ to 50 ₄ may be substantially circular. That is, the shape of the loop coil units 50 ₁ to 50 ₄ may be a circular shape, or may be another polygon that can be regarded as a substantially circular shape such as a nine-sided shape, a decagonal shape,.

  The thickness of the coil trace substrate 502 is, for example, about 0.2 mm. On the coil trace substrate 502, a coil pattern having an xy plane as a coil surface is formed. The coil trace substrate 502 is a flexible substrate, for example, an FPC (flexible printed circuit board). A coil trace substrate 502 including a coil pattern is configured as a so-called LC receiving circuit, and is configured to be able to receive a magnetic resonance signal from a subject.

The insulation reinforcing plates 504 ₁ and 504 ₂ are provided so as to sandwich the coil trace substrate 502 in order to protect and reinforce the coil trace substrate 502. The insulation reinforcing plates 504 ₁ and 504 ₂ have flexibility, and are formed of, for example, a PET (polyethylene terephthalate) material.

The exterior covers 506 ₁ and 506 ₂ integrally cover the coil trace substrate 502 and the insulation reinforcing plates 504 ₁ and 504 ₂ to protect them from the outside. The exterior covers 506 ₁ and 506 ₂ are flexible and are, for example, thermoformed with a foam material.

Since the coil trace substrate 502 is made of, for example, FPC, the insulation reinforcing plates 504 ₁ , 504 ₂ are made of, for example, PET material, and the outer covers 506 ₁ , 506 ₂ are thermoformed, for example, of foam material, the loop coil unit 50 ₁ is a coil having flexibility as a whole. The loop coil units 50 ₂ , 50 ₃ , and 50 ₄ have the same configuration as the loop coil unit 50 ₁ . The loop coil units 50 ₁ to 50 ₄ only need to have flexibility as a whole, and the material and the like of each component are not limited to those described above.

The four connecting portions 51 _{1 to} 51 ₄ are connecting portions having a rotation axis parallel to the Z axis, and connect the loop coil unit 50 ₁ and the loop coil unit 50 ₂ so as to be rotatable in the xy plane. FIG. 3 is a cross-sectional view taken along the line BB ′ of FIG. This cross-sectional portion includes a connecting portion 51 ₁ .

The connecting portion 51 ₁ includes a resin cylinder 510 and a resin rivet 512. The loop coil unit 50 ₁ and the loop coil unit 50 ₂ are provided with through holes parallel to the z-axis direction at the same xy position. A single resin cylinder 510 is inserted through the two through holes. A resin rivet 512 is inserted into the resin cylinder 510. The resin cylinder 510 and the resin rivet 512 constitute a rotation shaft, and the loop coil unit 50 ₁ and the loop coil unit 50 ₂ can rotate in the XY plane around the rotation shaft. It has become.

Since the loop coil unit 50 ₁ and the loop coil unit 50 ₂ are connected only by the connecting portion 51 _1, by rotating the other unit with respect to one unit around these, The relative positional relationship (relative position of the center point of each unit) can be adjusted.

The most important point is that this rotation axis is provided so as to be located at the center of the overlapping portion of the loop coil unit 50 ₁ and the loop coil unit 50 ₂ .

4 to 6 schematically show how the relative position of the loop coil unit 50 ₂ changes with respect to the loop coil unit 50 ₁ . Figure 4 in Figure 6, the connecting portion 51 ₁ and the center point of the loop coil unit 50 ₁ and the line segment D connecting the center O ₃ of the rotary shaft, the loop of the coil unit 50 _second center point and the connecting portion 51 ₁ A line segment E connecting the center point is shown.

In FIG. 4, the angle formed by the line segment D and the line segment E is 180 degrees. In this embodiment, this state is used as a reference. In this state, an overlapping portion between the coil surface of the loop coil unit 50 _{1 and} the coil surface of the loop coil unit 50 ₂ is defined as an overlapping portion C, and the area of the overlapping portion C in this state is defined as C1.

FIG. 5 shows a state where the loop coil unit 50 ₁ is rotated by θ around the rotation axis O ₃ of the connecting portion 51 _{1 with} respect to the loop coil unit 50 ₂ . Here, θ is assumed to satisfy 0 ° <θ ≦ 45 ° as will be described later. The area of the overlapping part C in this state is C2. Since the rotation axis O ₃ of the connecting portion 51 ₁ is provided at the center of the overlapping portion C, the area C2 of the overlapping portion C in this state is substantially the same as the area C1 of the overlapping portion C in the state of FIG. Become.

FIG. 6 shows a state in which the loop coil unit 50 ₁ is rotated by θ around the rotation axis O ₃ of the connecting portion 51 _{1 with} respect to the loop coil unit 50 ₂ . Here, θ is assumed to be −45 ° ≦ θ <0 ° as described later. The area of the overlapping part C in this state is C3. Also in this case, since the rotation axis O ₃ of the connecting portion 51 ₁ is provided at the center of the overlapping portion C, the area C3 of the overlapping portion C in this state is the area of the overlapping portion C in the state of FIG. It is almost the same as C1.

The reason why θ is limited to a range of ± 45 ° will be described. As schematically shown in FIG. 7 (in FIG. 7, for ease of explanation, the coil shape is circular), the loop coil unit is further rotated to make θ outside this range (+ 45 ° or more or − When less than 45 °) to, become the center position O ₁ and O ₂ of the two coils is approaching, the area of the overlapping portion C is to increase rapidly. For this reason, in the present embodiment, θ is limited as described above.

Thus, if θ is −45 ° ≦ θ ≦ 45 °, even if the loop coil unit 50 ₂ is rotated with respect to the loop coil unit 50 ₁ , the variation in the area of the overlapping portion C is substantially the same. Become. As a result, the influence of the magnetic field generated by one loop coil unit on the other loop coil unit is almost insensitive to fluctuations in the positional relationship between them, and the noise component increases due to mutual induction of the coils regardless of θ. It becomes possible to prevent. The receiving coil 10 may be provided with a mechanism such as a limiter that limits θ to the rotation amount. However, in the receiving coil 10 of the present embodiment, four loop coil units are arranged in an array. Therefore, structurally, θ inevitably falls within the range of −45 ° ≦ θ ≦ 45 °.

Incidentally, since it is composed of a resin for cylinder 510 and the resin rivets 512, connecting portions 51 _1, 51 _2, 51 _3, 51 ₄ rotation axis has a slight flexibility. Furthermore, since each loop coil unit has flexibility, for example, as shown in FIG. 8, the connection part between the loop coil units is lifted by hand, and the entire receiving coil 10 is moved in the Z-axis direction. It is also possible to deform it.

  When such flexibility is given, the receiving coil 10 can be deformed into various shapes.

  For example, as shown in FIG. 9, it is possible to deform the receiving coil 10 into a semi-cylindrical side shape. FIG. 9 shows a state in which the entire receiving coil 10 is deformed so as to draw an arc as viewed from the x-axis direction. In this way, the shape of the entire receiving coil 10 can be fitted to the abdomen of the subject, for example. Since the curvature of the entire receiving coil 10 can be arbitrarily set to some extent, the curvature should be set according to the shape of the body surface regardless of whether the patient is an adult or a child. Can do.

  Further, for example, as shown in FIG. 10, from the state shown in FIG. 9, by further rotating the connecting portion connecting the coil units while slightly bending the coil units along the X-axis direction, The entire receiving coil 10 can be deformed into a cone or a pyramid shape. In this way, the shape of the entire receiving coil 10 can be fitted to, for example, the shoulder of the subject or the breast. Even in this case, the height of the cone or pyramid can be set variously, and the shape can be fitted to the body surface shape of the patient.

Returning to FIG. 1, a tuning / matching circuit that is electrically connected to the coil pattern in the coil trace board in each loop coil unit 50 ₁ is incorporated in the board protection case 52 ₁ . Magnetic resonance signal output from the coil pattern is tuned / matched by the tuning / matching circuit, via a connecting cable 53 _1, it is outputted to the connector 54. The circuit board protection cases 52 ₂ , 52 ₃ , and 52 ₄ each have a tuning / matching circuit that is electrically connected to the coil pattern in the coil trace board 502 in each of the loop coil units 50 ₂ , 50 ₃ , and 50 ₄ . Each is incorporated.

The magnetic resonance signal received by each coil pattern is tuned / matched by this tuning / matching circuit, and is output to the substrate case 52 ₁ via the connection cables 53 ₂ , 53 ₃ , 53 ₄ . The substrate case 52 ₁ relays magnetic resonance signals from the loop coil units 50 ₂ , 50 ₃ , 50 ₄ and outputs them to the connection connector 54 via the connection cable 53 ₁ .

<Magnetic resonance imaging device>
Next, a magnetic resonance imaging apparatus (hereinafter abbreviated as “MRI apparatus”) including the receiving coil 10 will be described.

  FIG. 11 schematically shows the overall configuration of the magnetic resonance imaging apparatus 100. As shown in FIG. 11, the MRI apparatus 100 includes a static magnetic field magnet 1, a gradient magnetic field coil 2, a gradient magnetic field power supply 3, a high frequency coil 4, a transmission unit 5, a bed 6, a reception unit 8, The bed control unit 9, the reception coil 10 described above, and a computer system 30 are provided.

  The static magnetic field magnet 1 has a hollow cylindrical shape, and generates a uniform static magnetic field in a space inside the cylindrical shape. As the static magnetic field magnet 1, for example, a permanent magnet, a superconducting magnet or the like is used.

  The gradient magnetic field coil 2 has a hollow cylindrical shape and is disposed inside the static magnetic field magnet 1. The gradient coil 2 is composed of three coils corresponding to the X, Y, and Z axes orthogonal to each other. The gradient magnetic field coil 2 generates a gradient magnetic field in which the above three coils are individually supplied with electric current from the gradient magnetic field power supply 3 and the magnetic field strength is inclined along the X, Y, and Z axes. In FIG. 1, the Z-axis direction is the same direction as the static magnetic field. The gradient magnetic fields of the X, Y, and Z axes correspond to the slice selection gradient magnetic field Gs, the phase encoding gradient magnetic field Ge, and the readout gradient magnetic field Gr, respectively. The slice selection gradient magnetic field Gs is used to arbitrarily determine an imaging section. The phase encoding gradient magnetic field Ge is used to encode the phase of the magnetic resonance signal in accordance with the spatial position. The readout gradient magnetic field Gr is used to encode the frequency of the magnetic resonance signal in accordance with the spatial position.

  The high frequency coil 4 has a hollow cylindrical shape and is disposed inside the gradient magnetic field coil 2. A subject P placed on the bed 6 is inserted inside the high-frequency coil 4. The high frequency coil 4 is supplied with a high frequency pulse from the transmission unit 5 and generates a high frequency magnetic field. The high frequency coil 4 receives a magnetic resonance signal radiated from the subject P due to the influence of the high frequency magnetic field. The high-frequency coil 4 has an inner diameter that allows the subject P to easily pass through, and thus functions as a whole-body RF probe.

  The transmission unit 5 includes an oscillation unit, a phase selection unit, a frequency conversion unit, an amplitude modulation unit, and a high frequency power amplification unit (all not shown). 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 5 transmits a high frequency pulse corresponding to the Larmor frequency to the high frequency coil 4.

  The receiving coil 10 is disposed inside the high-frequency coil 4. In FIG. 11, the receiving coil 10 is disposed on the abdomen of the subject P. In this case, the receiving coil 10 is deformed into a semi-cylindrical shape so as to follow the body surface shape of the abdomen of the subject P. The receiving coil 10 receives a magnetic resonance signal radiated from the subject P. The receiving coil 10 is connected to the receiving unit 8 via the connection connector 54 and transmits a magnetic resonance signal to the receiving unit 8.

  The receiving unit 8 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 4 and the receiving coil 10. The receiving unit 8 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 receiving unit 8 includes a decoupling circuit. This circuit is configured to be able to remove the coupling caused by the minute fluctuations of the fluctuations C1, C2, and C3 of the overlapping portion C caused by the deformation of the receiving coil 10 shown in FIGS. 4 to 6, for example. . In other words, the allowable range of variation in the area of the overlapping portion of the loop coil unit in the reception coil 10 is determined according to the coupling removal capability of the decoupling circuit.

  The bed control unit 9 includes a movement mechanism unit and a movement control unit (both not shown). The moving mechanism unit reciprocates the bed 6 in the axial direction of the high-frequency coil 4, that is, in the left-right direction in FIG. 1. The movement control unit controls the movement mechanism unit so as to perform forward movement and backward movement described later.

  The computer system 30 includes an interface unit 30a, a data collection unit 30b, a reconstruction unit 30c, a storage unit 30d, a display unit 30e, an input unit 30f, and a control unit 30g.

  A gradient magnetic field power source 3, a transmission unit 5, a reception unit 8, and a bed control unit 9 are connected to the interface unit 30a. The interface unit 30 a inputs and outputs signals exchanged between these connected units and the computer system 30.

  The data collecting unit 30b collects digital signals of a plurality of channels obtained for each loop coil unit output from the receiving unit 8 via the interface unit 30a. The data collection unit 30b stores the collected digital signal, that is, magnetic resonance signal data, in the storage unit 30d.

  The reconstruction unit 30c performs post-processing, that is, reconstruction such as Fourier transform, on the plurality of channels of magnetic resonance signals stored in the storage unit 30d, and performs spectrum data or images of desired nuclear spins in the subject P. Create data. As described above, the receiving coil 10 is deformed so as to conform to the body surface shape of the subject P, and the magnetic resonance signals of each channel are received with high sensitivity, so that a high-quality image can be obtained. .

  The storage unit 30d stores magnetic resonance signal data and spectrum data or image data for each patient and each diagnostic site.

  The display unit 30e displays various information such as spectrum data or image data under the control of the control unit 30g. A display device such as a liquid crystal display is used as the display unit 30e.

  The input unit 30f receives various commands and operation inputs from the operator. As the input unit 30f, a pointing device such as a mouse or a trackball, a selection device such as a mode switch, or an input device such as a keyboard is used as appropriate.

  The control unit 30g includes a CPU, a memory, and the like, and comprehensively controls the above-described units.

As described above in detail, according to the present embodiment, in the receiving coil 10, the plurality of loop coil units 50 ₁ to 50 ₄ are arranged in a two-dimensional matrix. Further, the receiving coil 10 is configured such that a part of the loop coil units adjacent in the x-axis and y-axis directions overlap each other. Its adjacent loop coil units, due in part coupling 51 _{1-51 4} disposed at the center point of which overlap, are rotatably connected in one place. In this way, even if one of the connected loop coil units is rotated around the rotation axis with respect to the other loop coil unit, and the entire receiving coil is deformed, Since the area of the overlapping portion hardly changes, the neutralization state of mutual induction generated between adjacent coils can always be made constant. For this reason, even if the shape of the receiving coil 10 is changed, it is possible to receive a magnetic resonance signal while always maintaining a high S / N ratio.

The rotation according to the present embodiment, the connecting portion 51 _{1-51 4,} perpendicular to the coil plane of the loop coil unit 50 ₁ to 50 ₄ adjacent and provided at the center of the overlapping portion of the coil surface It has an axis O ₃ . Further, the other loop coil unit is rotatably connected to one loop coil unit via the rotation axis O ₃ . By having this rotating shaft O ₃ , the connecting portions 51 _{1 to} 51 ₄ can connect adjacent loop coil units to each other so as to be rotatable.

  In addition, the connection part of a loop coil unit is not restricted to a thing like this embodiment. In short, even if the relative positional relationship of the loop coil units changes, it is sufficient if the fluctuations in the area of the overlapping portions of the coil surfaces of the loop coil units can be connected so that they are within a predetermined range. .

Further, according to the present embodiment, the rotation amount of the rotating shaft O ₃ is such that the center points O ₁ and O _{2 of} the adjacent loop coil units and the rotating shaft O _{3 of the} connecting portion are aligned in a straight line. As a reference, it is limited to within ± 45 degrees. Thereby, the area of the overlapping part of the adjacent loop coil units is kept substantially constant.

Further, according to the present embodiment, each loop coil units 50 ₁ to 50 ₄ is flexible. In this way, in addition to the rotational movement by the connecting portion 51 _{1-51 4,} by further flexing the respective loop coil units, it is possible to three-dimensionally deforming the entire unit.

The flexible loop coil units 50 ₁ to 50 ₄ are formed on an FPC covered with foam-molded outer covers 506 ₁ and 506 ₂ . If it does in this way, it will become possible to give flexibility to the whole loop coil unit. The present invention is not limited to this structure, and any material may be used as long as the loop coil unit has flexibility.

  Further, the MRI apparatus 100 according to the present embodiment includes a receiving coil 10.

  The receiving coil 10 can be wound around a knee or the like, and can also be applied to a convex three-dimensional part such as a shoulder or a breast. That is, with the MRI apparatus 100 according to the present embodiment, it is not necessary to provide a receiving coil for each diagnostic part, so that it is not necessary to replace the receiving coil at the time of diagnosis. As a result, the burden on the operator is reduced and the time required for diagnosis can be shortened. Furthermore, since it is not necessary to provide a plurality of different receiving coils, it is possible to reduce the device cost. The configuration of the MRI apparatus 100 is not limited to that shown in FIG. 11 and may be any MRI apparatus to which the receiving coil 10 of the present invention can be applied.

  Further, according to the MRI apparatus 100 according to the above-described embodiment, since the entire receiving coil 10 has good flexibility, it is not necessary to reduce the coil units and increase the number thereof.

  In the above embodiment, the number of loop coil units in the receiving coil 10 is four, but the present invention is not limited to this. For example, the number of loop coil units may be two, or three or more. The number of loop coil units to be provided depends on the shape of the receiving coil. For example, when the shape of the entire receiving coil is a square, the number of loop coil units may be N × N (N is an integer) such as 2 × 2, 3 × 3,.

It is an external view of the coil for reception concerning one embodiment of the present invention. It is A-A 'sectional drawing of FIG. It is B-B 'sectional drawing of FIG. It is a schematic diagram (the 1) which shows the mode of rotation of the other loop coil unit with respect to one loop coil unit. It is a schematic diagram (the 2) which shows the mode of rotation of the other loop coil unit with respect to one loop coil unit. It is a schematic diagram (the 3) which shows the mode of rotation of the other loop coil unit with respect to one loop coil unit. It is a figure for demonstrating the limit of the rotation angle of a loop coil unit. It is a figure for demonstrating the mode of a deformation | transformation of a loop coil unit. It is a figure which shows the modification (the 1) of the shape of a receiving coil. It is a figure which shows the modification (the 2) of the shape of a receiving coil. 1 is a schematic configuration diagram of a magnetic resonance imaging apparatus according to an embodiment of the present invention.

Explanation of symbols

1 static field magnet 2 gradient coil 3 gradient power supply 4 high frequency coil 5 transmission unit 6 bed 8 the receiver 9 bed controller 10 receiving coil 30 computer system 50 _1, 50 _2, 50 _3, 50 ₄ loop coil unit 51 ₁ , 51 _2, 51 _3, 51 ₄ connecting portions 52 _1, 52 _2, 52 _3, 52 ₄ board case 53 _1, 53 _2, 53 _3, 53 ₄ connected cable 54 connector 100 magnetic resonance imaging apparatus 502 coil trace substrate 504 ₁ , 504 ₂ Insulation reinforcement plate 506 ₁ , 506 ₂ Exterior cover 510 Resin cylinder 512 Resin rivet P Subject

Claims (6)

In the high-frequency coil in which a plurality of surface coils are arranged so that part of the coil surfaces of adjacent surface coils overlap each other,
A high frequency device comprising a connecting portion for connecting adjacent surface coils so that the variation in the area of the overlapping portion of the coil surface is within a predetermined range even if the relative positional relationship between the adjacent surface coils is changed. coil. The connecting portion is
A rotating shaft provided at the center of the overlapping portion of the coil surface orthogonal to the coil surface of the surface coil to be coupled;
2. The high frequency coil according to claim 1, wherein the other surface coil is rotatably connected to the one surface coil via the rotating shaft.   3. The rotation amount of the rotation shaft is within ± 45 degrees with reference to a state in which the respective center points of adjacent surface coils and the rotation shaft are aligned in a straight line. High frequency coil.   The high frequency coil according to any one of claims 1 to 3, wherein each of the surface coils has flexibility. The flexible surface coil is formed on a flexible substrate,
The high-frequency coil according to claim 4, wherein the flexible substrate is covered with an exterior portion made of a foam material.   A magnetic resonance imaging apparatus comprising the high-frequency coil according to claim 1 as a high-frequency receiving coil.

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