JP2002085366A - Rf coil for mri and mri device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily attach and remove an RF coil for MRI and to make a wearer feel less compressed. SOLUTION: The RF coil 100 for MRI, with the assumption of perpendicular X, Y and Z directions, includes a first coil 1 having a curved coil surface curved in the X direction but not in the Z direction, a second coil 2 disposed at the first end of the first coil 1 along the X direction and having a planar coil surface crossing the curved coil surface of the first coil 1, and a third coil 3 disposed at the second end of the first coil 1 along the X direction and having a planar coil surface crossing the curved coil surface of the first coil 1. The first coil 1 is biased in the projecting direction of the curved coil surface beyond an imaginary XZ plane v passing through the centers of the second and third coils 2 and 3. The labor and time required to attach and remove the coils can be saved. Quadrature transmission and reception excellent in perpendicularity can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an MRI (Magnetic
Resonance Imaging) RF coil (Radio Frequenc)
y) and the MRI apparatus, more specifically, an MRI R which can be easily attached and detached and can reduce the feeling of pressure upon mounting.
The present invention relates to an F coil and an MRI apparatus using the MRI RF coil.

[0002]

2. Description of the Related Art Site-specific coils (for example, head coils, abdominal coils, neck coils, and knee coils) are known as RF coils for MRI. A wrap-around type coil is known as one type of the site-specific coil, which is mounted so as to be wound around a subject so that the surface of the subject and the coil surface are brought into close contact with each other. For example, in the case of a wrap-around type abdomen coil, it is attached so as to be wound around the abdomen.

[0003]

The conventional wrap-around coil has a problem that it takes time and effort to attach and detach the coil. In addition, there is a problem that the subject is likely to receive an uncomfortable feeling of pressure. Therefore, an object of the present invention is to provide an MRI RF coil that can be easily attached and detached and that can reduce a feeling of pressure at the time of mounting, and an MRI apparatus using the MRI RF coil.

[0004]

According to a first aspect, the present invention provides a first coil having a coil surface extending in an XZ plane direction or a surface direction close to the XZ plane direction, assuming orthogonal X, Y, and Z directions. A second coil having a coil surface provided on a first end side in the X direction of the first coil and extending in a YZ plane direction or a plane direction close thereto, and a second coil provided on a second end side in the X direction of the first coil. And a third coil having a coil surface extending in a YZ plane direction or a surface direction close to the YZ plane direction, wherein three surfaces are formed by a concave wall including the first coil, the second coil, and the third coil. Provided is an MRI RF coil, wherein a space for sandwiching a target portion is formed in a surrounded portion. In the MRI RF coil according to the first aspect, the mounting operation can be completed simply by sandwiching the target portion between the portions surrounded by the concave wall on the three surfaces, and the target portion can be photographed using each coil. It becomes possible. That is, it can be easily attached and detached in a short time. Further, even in the mounted state, since one side (usually, the upper side) is open, it is possible to reduce the subject's uncomfortable feeling of pressure.

According to a second aspect, the present invention provides an M
In the RF coil for RI, the first coil and the second
At least one of the coil and the third coil has a curved coil surface curved in any direction, thereby providing an MRI RF coil. In the MRI RF coil according to the second aspect, it is possible to increase the proximity between the coil surface and the target portion by fitting the curved coil surface to the shape of the target portion, thereby improving the RF pulse transmission efficiency and NM.
The reception sensitivity of the R signal can be improved.

According to a third aspect, the present invention provides an M
In the RF coil for RI, the first coil and the second
An MRI RF coil is provided, wherein at least one of the coil and the third coil is a ladder coil having a plurality of parallel elements. In the MRI RF coil according to the third aspect, since at least one coil is a ladder coil, an excitation magnetic field region and a sensitivity region can be uniformly formed over a wide range.

According to a fourth aspect, the present invention provides an M
The present invention provides an MRI RF coil, wherein the second coil and the third coil are arranged so as to face each other in a C-shape. In the MRI RF coil according to the fourth aspect, since the second coil and the third coil are arranged so as to open in a C shape and face each other, the second coil and the third coil, and the target site And both side surfaces of the device can be fitted better, and the transmission efficiency of the RF pulse and the reception sensitivity of the NMR signal can be improved.

[0008] In a fifth aspect, the present invention provides an orthogonal X,
Assuming the Y and Z directions, it is curved in the X direction and Z
A first coil having a curved coil surface that does not curve in the direction;
The first coil is provided on the first end side in the X direction of the first coil.
A second coil having a plane coil surface that intersects a curved coil surface of the coil; and a second coil provided at a second end side in the X direction of the first coil and having a plane coil surface that intersects the curved coil surface of the first coil. MRI comprising three coils, wherein the first coil is closer to the convex side of the curved coil surface than an imaginary XZ plane passing through the centers of the second coil and the third coil. An RF coil is provided.
In the MRI RF coil according to the fifth aspect, an excitation magnetic field region and a sensitivity region having high uniformity are formed on the opposite side (usually upward) of the convex direction of the curved coil surface of the first coil, and the Y-direction An oscillating magnetic field can be generated or detected. Further, the second coil and the third coil form a highly uniform excitation magnetic field region and a high sensitivity region in a portion sandwiched between the two coils, and can generate or detect an oscillating magnetic field in the X direction. Therefore, quadrature transmission or quadrature reception with the gap between the second coil and the third coil as an imaging region can be efficiently performed. Therefore, the mounting operation is completed only by sandwiching the target site in the gap between the second coil and the third coil, and the mounting operation can be easily performed in a short time.
Further, even in the mounted state, since one side (usually, the upper side) is open, it is possible to reduce the subject's uncomfortable feeling of pressure.

[0009] In a sixth aspect, the present invention provides a method, comprising:
Assuming the Y and Z directions, it is curved in the X direction and Z
A first coil having a curved coil surface that does not curve in the direction;
The first coil is provided on the first end side in the X direction of the first coil.
The second direction in the X direction intersects the curved coil surface of the coil and is in the Y direction.
A second coil having a curved coil surface curved toward the concave side toward the end and not curved in the Z direction; and a curved coil surface of the first coil provided on the second end of the first coil in the X direction. A third coil having a curved coil surface that intersects and curves in the Y direction with the concave surface facing the first end side and does not curve in the Z direction, wherein the first coil is the second coil And an MRI RF coil which is closer to the convex direction side of the curved coil surface than the virtual XZ plane passing through the center of the third coil. In the MRI RF coil according to the sixth aspect, since the curved coil surfaces of the second coil and the third coil fit on both side surfaces of the target portion and function like a saddle coil, the curved coil surface and the target portion can be separated from each other. By increasing the proximity, the transmission efficiency of the RF pulse and the reception sensitivity of the NMR signal can be improved.

According to a seventh aspect, the present invention provides an M
The present invention provides an MRI RF coil, wherein the second coil and the third coil are arranged so as to face in parallel. In the MRI RF coil according to the seventh aspect, the second coil and the third coil disposed so as to face in parallel can generate or detect an oscillating magnetic field in a direction orthogonal to the oscillating magnetic field applied to the first coil. Become. Therefore, the orthogonality between the 0 ° component and the 90 ° component in quadrature transmission or quadrature reception can be improved.

According to an eighth aspect, the present invention provides an M
In the RF coil for RI, the second coil and the third coil are arranged so as to open in a C shape toward the side opposite to the side where the first coil is shifted and to face each other. And an MRI RF coil. In the MRI RF coil according to the eighth aspect, the second coil and the third coil
Since the distance between the coils increases as the distance increases, the coil can be more easily attached and detached. Further, the second coil and the third coil and both side surfaces of the target portion fit better, so that the transmission efficiency of the RF pulse and the reception sensitivity of the NMR signal can be improved.

According to a ninth aspect, the present invention provides an M
The present invention provides an MRI RF coil in which the second coil and the third coil are opened in a C-shape and the facing angle is variable. In the MRI RF coil according to the ninth aspect, the angle at which the second coil and the third coil face each other is increased, so that the MRI RF coil can be easily attached and detached. In addition, after mounting, by reducing the angle at which the second coil and the third coil face each other, it becomes possible to increase the proximity to both side surfaces of the target portion, thereby improving the transmission efficiency of the RF pulse and the reception of the NMR signal. Sensitivity can be improved.

According to a tenth aspect, the present invention provides an MRI RF coil having the above-mentioned configuration, wherein the first coil is a ladder coil having a plurality of parallel elements. . In the MRI RF coil according to the tenth aspect, since the first coil is a ladder coil, an excitation magnetic field region and a sensitivity region can be uniformly formed over a wide range.

According to an eleventh aspect of the present invention, in the MRI RF coil having the above-mentioned structure, the second coil and the third coil are loop coils and constitute a figure-eight coil. An RF coil is provided. In the MRI RF coil according to the eleventh aspect, since the second coil and the third coil are loop coils, the configuration can be simplified. Further, by configuring the figure eight coil, it is possible to make the characteristics of both coils uniform, and it is possible to transmit RF pulses and receive NMR signals with high accuracy.

According to a twelfth aspect, the present invention provides the MRI RF coil having the above-mentioned configuration, wherein the second coil and the third coil are ladder coils having a plurality of parallel elements. Provide coils. In the MRI RF coil according to the twelfth aspect, since the second coil and the third coil are ladder coils, the excitation magnetic field region and the sensitivity region can be formed uniformly over a wide range.

According to a thirteenth aspect, the present invention provides an MRI comprising the MRI RF coil configured as described above.
Provide equipment. The MRI apparatus according to the thirteenth aspect includes the MRI RF coil having the above configuration.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. Note that the present invention is not limited by this.

FIG. 1 is a block diagram of an MRI apparatus including an MRI RF coil according to the present invention. This MRI apparatus 10
At 00, the magnet assembly 10 has a space (hole) for inserting a subject therein, and a static magnetic field coil 10p for applying a constant static magnetic field to the subject so as to surround the space. , Slice axis, lead axis,
Gradient magnetic field coil 10 for generating gradient magnetic field of phase axis
g and RF for exciting nuclear spins in the subject
MRI RF coil 100t for transmitting pulse
And a receiving MRI for detecting an NMR signal from the subject
RF coil 100r is disposed. The static magnetic field coil 10p is connected to a static magnetic field power supply 32. The gradient magnetic field coil 10g is connected to a gradient magnetic field drive circuit 23. The transmitting MRI RF coil 100
t is connected to the RF power amplifier 24. The receiving MRI RF coil 100 r is connected to a preamplifier 25. Note that a permanent magnet may be used instead of the static magnetic field coil 10p.

The sequence storage circuit 26 operates the gradient magnetic field drive circuit 23 based on the stored pulse sequence in accordance with a command from the computer 27 to generate a gradient magnetic field from the gradient magnetic field coil 10g of the magnet assembly 10 and By operating the gate modulation circuit 28, the carrier wave output signal of the RF oscillation circuit 29 is modulated into a pulse signal having a predetermined timing and a predetermined envelope shape, and the resulting signal is applied to the RF power amplifier 24 as an RF pulse. After power amplification, the M
This is applied to the RI RF coil 100t to selectively excite a desired slice area. The preamplifier 25 amplifies the NMR signal from the subject detected by the MRI RF coil 100 r of the magnet assembly 10 and inputs the amplified signal to the phase detector 30. The phase detector 30 uses the carrier output signal of the RF oscillation circuit 29 as a reference signal, and
The signal is phase-detected and supplied to an A / D converter 31. A /
The D converter 31 converts the analog signal after the phase detection into a digital signal, and inputs the digital signal to the computer 27. Computer 27
Reads data from the A / D converter 31, performs an image reconstruction operation, and generates an image of a desired slice area. This image is displayed on the display device 33. Further, the computer 27 is responsible for overall control such as receiving information input from the operation console 32. In addition,
The MRI apparatus 1000 is an interventional (in
An open MRI apparatus used for terventional MRI may be used.

First Embodiment FIG. 2 shows an MRI RF according to a first embodiment of the present invention.
FIG. 2 is a perspective view schematically showing a main part of the coil 100. The MRI RF coil 100 has a first coil 1 having a curved coil surface that is curved in the X direction but not curved in the Z direction, assuming orthogonal X, Y, and Z directions.
A second coil 2 provided on the first end side of the coil 1 in the X direction and having a plane coil surface intersecting the curved coil surface of the first coil 1; and a second coil 2 on the second end side of the first coil 1 in the X direction. And a third coil 3 having a plane coil surface that intersects the curved coil surface of the first coil 1. The first coil 1 is closer to the convex direction side of the curved coil surface than an imaginary XZ plane v passing through the centers of the second coil 2 and the third coil 3. Bo is a static magnetic field formed in the Z direction. By is the oscillating magnetic field in the y direction transmitted or received by the first coil 1. Bx is an oscillating magnetic field in the x direction transmitted or received by the second coil 3 and the third coil 3. The first coil 1 is a ladder coil having a plurality of parallel elements E. The second coil 3 and the third coil 3 are rectangular loop coils facing in parallel. In the case of performing quadrupole transmission, that is, quadrature transmission, the feeder 12 of the first coil 1
The 0 ° component of the RF pulse is applied from the F power amplifier 24 (refer to FIG. 1), and the 90 ° component of the RF pulse is applied to the power supply unit 13 of the second coil 3 and the third coil 3. The power ratio between the 0 ° component and the 90 ° component is:
It is preferable to adjust the rotating magnetic field generated by the oscillating magnetic fields By and Bx so that the circularity is as high as possible. When quadrupole reception, that is, quadrature reception, is performed, the 0 ° component of the NMR signal extracted from the power supply section 12 of the first coil 1 and the NMR signal extracted from the power supply section 13 of the second coil 2 and the third coil 3 are used. 90 ° of NMR signal
The components are sent to a preamplifier 25 (see FIG. 1). The amplification ratio between the 0 ° component and the 90 ° component is preferably adjusted so that the SNR (Signal to Noise Ratio) of the combined signal after the phase control is as high as possible. When performing quadrupole transmission / reception, the MRI RF coil 100 includes:
It also functions as 100t (transmitting coil) and 100r (receiving coil) in FIG.

FIG. 3 shows the MRI RF coil 100 of FIG.
FIG. 2 is a development view showing a first coil 1 of FIG. The first coil 1
, A series circuit of capacitors Ca and Cb is provided between one connection point of the element E and a capacitor C1 is provided between the other connection points. The capacitor C
The core wire and the external conductor of the coaxial cable A1 derived from the power supply unit 12 are connected to both ends of the terminal a.
As a result, at the time of transmitting an RF pulse or receiving an NMR signal, a high-frequency current flows in the direction of arrow i1 (solid line or dotted line). The reason for using a coaxial cable is that
This is to suppress the occurrence of unnecessary electrical interference between the coil 2 and the third coil 3 and the like.

FIG. 4 shows a magnetic flux distribution F1 applied to the first coil 1. As shown in FIG. The first coil 1 generates and receives an oscillating magnetic field By in a Y direction orthogonal to a magnetic flux distribution line in the X direction. Since the first coil 1 is a ladder coil and the elements E in the Y direction are stretched at a plurality of locations, a large number of magnetic fluxes parallel to the X direction over a wider area than the one-turn coil having the same outer diameter. A distribution line is obtained, and an excitation magnetic field region and a sensitivity region with excellent uniformity can be formed.

FIG. 5 shows the MRI RF coil 100 shown in FIG.
FIG. 5 is a development view showing a second coil 2 and a third coil 3 of FIG. The core of one end of the coaxial cable A2 and an external conductor are connected to the center of one side of the second coil 2, and a capacitor C2 is provided on the other side. The core of one end of the coaxial cable A3 and an external conductor are connected to the center of one side of the third coil 3, and a capacitor C3 is provided on the other side. Generally, the capacitances of the capacitors C2 and C3 are equal. The core wire at the other end of the coaxial cable A2 and the outer conductor at the other end of the coaxial cable A3 are
3 are connected to both ends of a series circuit of capacitors Cα and Cβ provided between the terminals. The coaxial cable A
The outer conductor at the other end of the cable 2 is connected to the core wire at the other end of the coaxial cable A3. As a result, when transmitting an RF pulse or receiving an NMR signal, a high-frequency current flows through the second coil 2 in the direction of the arrow i2 (solid line or dotted line), and the high-frequency current flows through the third coil 3 in the direction of the arrow i3. Electric current flows. That is, the second coil 2 and the third coil 2
The coil 3 forms a figure eight coil. Note that the second coil 2 and the third coil 3 may be connected in parallel without using the figure-eight coil.

FIG. 6 shows a magnetic flux distribution F2 applied to the second coil 3 and the third coil 3. As shown in FIG. The second coil 2 and the third coil 3 generate and receive an oscillating magnetic field Bx in the X direction orthogonal to the magnetic flux distribution line in the vertical direction.

As shown by a solid line in FIG. 7, for example, when the abdomen is photographed, the mounting state of the MRI RF coil 100 is as follows.
In this state, the back of the subject P in the lying posture is placed on the first coil 1, and the abdomen is sandwiched in the gap between the second coil 2 and the third coil 3. As shown by the broken line in FIG. 7, the subject P ′ in the posture in which the upper body is raised is changed to the sleeping posture,
Alternatively, the MRI RF coil 100 can be attached and detached only by changing from a lying posture to a posture in which the upper body is raised.

The MRI R according to the first embodiment described above
According to the F coil 100, the second coil is located above the first coil 1.
By sandwiching the target portion of the subject P in the gap between the coil and the third coil, quadrature transmission and reception can be performed efficiently without giving the subject an uncomfortable feeling of pressure. For example, an abdomen and a spine can be imaged with an RF transmission power of about 3 kW in a 3T static magnetic field.

Second Embodiment FIG. 8 shows an RF for MRI according to a second embodiment of the present invention.
FIG. 2 is a perspective view schematically showing a main part of a coil 200. In this MRI RF coil 200, the second coil 22 is provided on the −X direction side (outside) of the −X direction end of the first coil 1, and on the + X direction side (outside) of the first coil 1 on the + X direction end.
Is provided with a third coil 23. According to the MRI RF coil 200 according to the second embodiment, the second
Since the distance between the coil 22 and the third coil 23 is increased,
A wider subject can be photographed. In addition, by adjusting the distance between the second coil 22 and the third coil 23 in a wide direction, the power ratio between the 0 ° component and the 90 ° component can be optimized for quadrature transmission and reception.

Third Embodiment FIG. 9 shows an RF for MRI according to a third embodiment of the present invention.
It is a perspective view which shows the principal part of the coil 300 typically. In this MRI RF coil 300, the second coil 32 is provided on the + X direction side (inside) of the first coil 1 in the −X direction end, and on the −X direction side (inside) of the + X direction end of the first coil 1.
Is provided with a third coil 33. According to the MRI RF coil 300 according to the third embodiment, the second
Since the distance between the coil 32 and the third coil 33 is reduced,
The transmission efficiency of the RF pulse and the reception sensitivity of the NMR signal can be improved. In addition, by adjusting the distance between the second coil 32 and the third coil 33 in the narrow direction, the power ratio between the 0 ° component and the 90 ° component can be optimized for quadrature transmission and reception.

Fourth Embodiment FIG. 10 shows an MRI R according to a fourth embodiment of the present invention.
It is a perspective view which shows the principal part of F coil 400 typically. In the MRI RF coil 400, the first coil 41
Is a loop coil having a curved coil surface that is curved in the X direction and not curved in the Z direction. According to the MRI RF coil 400 according to the fourth embodiment, since the first coil 41 is a loop coil, the configuration can be simplified.

Fifth Embodiment FIG. 11 shows an MRI R according to a fifth embodiment of the present invention.
It is a perspective view which shows the principal part of F coil 500 typically. In this MRI RF coil 500, the second coil 52
Is a ladder coil having a plurality of parallel elements E2. The third coil 53 is a ladder coil having a plurality of parallel elements E3. According to the MRI RF coil 500 according to the fifth embodiment described above, since the second coil 52 and the second coil 53 are ladder coils, the uniformity of the excitation magnetic field region and the sensitivity region can be improved.

Sixth Embodiment FIG. 12 shows an MRI R according to a sixth embodiment of the present invention.
It is a perspective view which shows the principal part of F coil 600 typically. In this MRI RF coil 600, the second coil 62 and the third coil 63 having a plane coil surface are formed in a C-shape toward the side opposite to the side where the first coil 1 having the curved coil surface is shifted. They are arranged to open and face each other.
The illustrated first coil 1 is a ladder coil. The dimensions are, for example, a width of 386 mm in the X direction, a height of 102 mm in the Y direction, a depth of 200 mm in the Z direction, and a lower half of an elliptical birdcage coil.
It is shaped like a part. The first coil 1
May be a loop coil. The illustrated second coil 62 and third coil 63 are loop coils. The dimensions are, for example, a width in the X direction of 47 mm, a height in the Y direction of 174 mm, and a depth in the Z direction of 240 mm.
The second coil 62 and the third coil 63 may be ladder coils. The interval between the lower elements of the second coil 62 and the third coil 63 is, for example, 28
0 mm. Further, the second coil 62 and the third coil
The coils 63 may be disposed at both ends in the X direction of the first coil 1, may be disposed outside the both ends, or may be disposed inside the both ends.

FIG. 13 shows the second coil 62 and the first coil 1 when the relative coordinate x2 in the −X direction of the lower element of the second coil 62 is changed with reference to the coordinates of each coil having the above dimensions. (Solid line) and the characteristic of the mutual inductance M3 between the third coil 63 and the first coil 1 when the relative coordinate x3 in the + X direction of the lower element of the third coil 63 is changed (solid line). The simulation result (broken line) is shown. The angle θ at which the second coil 62 and the third coil 63 open and face each other in a C shape is 30 °. In this case, the second
The absolute coordinate in the X direction of the lower element of the coil 62 is represented by “−
140 ", the absolute coordinate of the relative coordinate x2 is" -x2
−140 ”. When the absolute coordinate of the lower side element of the third coil 63 in the X direction is represented by “+140”,
The absolute coordinate of the relative coordinate x3 is “+ x3 + 140”.
The mutual inductance M2 between the second coil 62 and the first coil 1 and the mutual inductance M3 between the third coil 63 and the first coil 1 have the same value with opposite signs at relative coordinates x2 = x3. That is, by arranging the second coil 62 and the third coil 63 in mirror symmetry with respect to the center axis of the imaging region, the effects of the mutual inductances M2 and M3 can be canceled out, and 0 in quadrature transmission / reception.
The orthogonality between the ° component and the 90 ° component can be increased.

The MRI R according to the sixth embodiment described above.
According to the F coil 600, since the interval between the second coil 62 and the third coil 63 increases as it goes upward, it becomes easier to attach and detach. Further, at the time of mounting, the plane coil surfaces of the second coil 62 and the third coil 63 and both side surfaces of the subject fit better, so that the transmission efficiency of the RF pulse and the reception sensitivity of the NMR signal are reduced. Can be improved.

-Seventh Embodiment- FIG. 14 shows an MRI R according to a seventh embodiment of the present invention.
It is a perspective view which shows the principal part of F coil 700 typically. In the MRI RF coil 700, the hinge 70
The angle △ θ at which the second coil 72 and the third coil 73 are opened in the shape of the letter “C” is variable. According to the MRI RF coil 700 according to the seventh embodiment described above, the attachment / detachment can be further facilitated by increasing the angle △ θ so that the subject can easily change the posture at the time of attachment / detachment. In addition, by adjusting the angle △ θ so as to fit both sides of the subject at the time of mounting, the transmission efficiency of the RF pulse and the reception sensitivity of the NMR signal can be further improved.

The second coil 72 and the third coil 7
3, and if those cover members are made of a flexible material,
Without using the hinge 70, the angle △ θ becomes substantially variable. In this case, by mounting the cover member so as to be in contact with the subject, it becomes possible to deform each coil following body movement due to breathing or the like, and the proximity between the coil surface and the target portion of the subject is improved. Can be further enhanced.

-Eighth Embodiment- FIG. 15 shows an MRI R according to an eighth embodiment of the present invention.
It is a perspective view which shows the principal part of F coil 800 typically. The MRI RF coil 800 includes a first coil 1 having a curved coil surface that is curved in the X direction but not curved in the Z direction, assuming orthogonal X, Y, and Z directions. 1 is provided at the first end side in the X direction, intersects with the curved coil surface of the first coil 1, is curved in the Y direction with a concave surface toward the second end side in the X direction, and is not curved in the Z direction. A second coil having a coil surface, and a concave surface provided on the second end side of the first coil 1 in the X direction and intersecting with the curved coil surface of the first coil 1 and having a concave surface on the first end side in the Y direction. And a third coil 83 having a curved coil surface that is curved toward the outside and not curved in the Z direction. The first coil 1 includes the second coil 82 and the third coil 8.
3 is closer to the convex direction of the curved coil surface than the virtual XZ plane v passing through the center of the curve 3. The first coil 1 is a ladder coil having a plurality of parallel elements E. The second coils 82 and 83 function as saddle coils whose curved surfaces face each other.

The MRI RF according to the eighth embodiment described above.
According to the coil 800, since the curved coil surfaces of the second coils 82 and 83 fit well with both side surfaces of the subject,
The transmission efficiency of the RF pulse and the reception sensitivity of the NMR signal can be further improved.

-Other Embodiments- (1) The MRI RF coil according to the present invention is not limited to the abdominal coil, but is also used as a coil for each part to be attached to, for example, the cervical vertebra, occipital region, shoulder, elbow, arm, and leg. it can. (2) A part other than the back of the subject may be located on the first coil of the MRI RF coil. For example, the abdomen of the subject may be positioned. (3) The coil surface of the first coil of the MRI RF coil is
It may be a plane coil plane along the XZ plane.

[0039]

The RF coil and MR for MRI of the present invention
According to the I device, one side of the coil surface of the first coil is
Since it can be mounted simply by sandwiching the target part of the subject in the imaging region formed in the gap between the coil and the third coil, the time and effort for attachment and detachment can be saved. Also, quadrature transmission and reception with excellent orthogonality can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram of an MRI apparatus including an MRI RF coil of the present invention.

FIG. 2 is a perspective view schematically showing a main part of the MRI RF coil according to the first embodiment.

FIG. 3 is a developed view showing a first coil of the MRI RF coil of FIG. 2;

FIG. 4 is an explanatory diagram showing a magnetic flux distribution applied to a first coil of the MRI RF coil of FIG. 2;

FIG. 5 is a developed view showing a second coil and a third coil of the MRI RF coil of FIG. 2;

FIG. 6 is an explanatory diagram showing a magnetic flux distribution applied to a second coil and a third coil of the MRI RF coil of FIG. 2;

7 is an explanatory diagram showing a posture of a subject in a mounted state and a detached state of the MRI RF coil of FIG. 2;

FIG. 8 is a perspective view schematically showing a main part of an MRI RF coil according to a second embodiment.

FIG. 9 is a perspective view schematically showing a main part of an MRI RF coil according to a third embodiment.

FIG. 10 is a perspective view schematically showing a main part of an MRI RF coil according to a fourth embodiment.

FIG. 11 is a perspective view schematically showing a main part of an MRI RF coil according to a fifth embodiment.

FIG. 12 is a perspective view schematically showing a main part of an MRI RF coil according to a sixth embodiment.

FIG. 13 is a graph showing mutual inductance characteristics of the MRI RF coil of FIG.

FIG. 14 is a perspective view schematically showing a main part of an MRI RF coil according to a seventh embodiment.

FIG. 15 is a perspective view schematically showing a main part of an MRI RF coil according to an eighth embodiment.

[Explanation of symbols]

100, 200, 300, 400 MRI RF coil 500, 600, 700, 800 MRI RF coil 1, 41 First coil 2, 22, 32, 52, 62, 72, 82, Second coil 3, 23, 33 , 53, 63, 73, 83 Third coil 70 Hinge v Virtual XZ plane

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Mitsuru Tamura 4-7-7 Asahigaoka, Hino-shi, Tokyo Inside GE Yokogawa Medical Systems Co., Ltd. (72) Inventor Akira Nabeya 4-chome, Asahigaoka, Hino-shi, Tokyo Address 127 127 GE Yokogawa Medical System Co., Ltd. F-term (reference) 4C096 AB37 AB47 CC07 CC08 CC12 CC14

Claims (13)

[Claims] 1. A first coil having a coil surface extending in an XZ plane direction or a surface direction close to the XZ plane direction, assuming orthogonal X, Y, and Z directions, and a first end side of the first coil in the X direction. A second coil having a coil surface extending in a YZ plane direction or a surface direction close thereto, and a coil surface provided on the second end side in the X direction of the first coil and extending in a YZ plane direction or a surface direction close thereto. A third coil having a concave portion formed by the first coil, the second coil, and the third coil. An MRI RF coil, comprising: 2. The MRI RF coil according to claim 1, wherein at least one of the first coil, the second coil, and the third coil has a curved coil surface curved in any direction. An RF coil for MRI characterized by the following. 3. An MRI according to claim 1 or claim 2.
An RF coil for MRI, wherein at least one of the first coil, the second coil, and the third coil is a ladder coil having a plurality of parallel elements. 4. The MRI RF coil according to claim 1, wherein the second coil and the third coil are arranged so as to face each other in a C-shape. An RF coil for MRI characterized by the following. 5. Assuming orthogonal X, Y, and Z directions, a first coil having a curved coil surface that curves in the X direction but does not curve in the Z direction; A second coil provided on a first end side and having a plane coil surface crossing a curved coil surface of the first coil; and a curved coil of the first coil provided on a second end side in the X direction of the first coil. A third coil having a plane coil surface intersecting with a plane, wherein the first coil is on a convex side of the curved coil surface with respect to a virtual XZ plane passing through the centers of the second coil and the third coil. MR characterized by being close to
RF coil for I. 6. Assuming orthogonal X, Y, and Z directions, a first coil having a curved coil surface that curves in the X direction but does not curve in the Z direction; A second coil provided on the first end side and having a curved coil surface that intersects the curved coil surface of the first coil, is curved in the Y direction with a concave surface facing the second end in the X direction, and is not curved in the Z direction; A coil, which is provided on a second end side in the X direction of the first coil, intersects a curved coil surface of the first coil, curves in the Y direction with a concave surface facing the first end side, and in the Z direction. A third coil having a curved coil surface that does not bend, the first coil being closer to the convex direction side of the curved coil surface than an imaginary XZ plane passing through the centers of the second coil and the third coil. An MRI RF coil, comprising: 7. An MRI according to claim 5 or claim 6.
M coil, wherein the second coil and the third coil are arranged so as to face in parallel.
RF coil for RI. 8. An MRI according to claim 5 or claim 6.
In the RF coil for use, the second coil and the third coil are:
An RF coil for MRI, wherein the first coil is arranged so as to open in a C-shape toward the side opposite to the side on which the first coil is shifted and to face each other. 9. The MRI RF coil according to claim 8, wherein the second coil and the third coil are opened in a V-shape and the angle at which they face each other is variable.
F coil. 10. The MRI RF coil according to claim 5, wherein the first coil is a ladder coil having a plurality of parallel elements. 11. The MRI RF coil according to claim 5, wherein the second coil and the third coil are connected to each other.
An MRI RF coil, wherein the coil is a loop coil and forms a figure-eight coil. 12. The MRI RF coil according to claim 5, wherein the second coil and the third coil are connected to each other.
An RF coil for MRI, wherein the coil is a ladder coil having a plurality of parallel elements. 13. An MRI apparatus comprising the MRI RF coil according to claim 5. Description: