KR20210068998A - Apparatus for magnetic resonance imaging having elliptical birdcage shape for improvement of magnetic field uniformity and efficiency in whole-body rf coil - Google Patents

Abstract

According to an embodiment of the present invention, in a magnetic resonance image acquisition device in a shape of an elliptical column which is perpendicular to an ellipse corresponding to upper and lower surfaces of a virtual elliptical column and is provided to be parallel to each other along a side of the virtual elliptical column, the magnetic resonance image acquisition device includes: a plurality of high-frequency coils for transmitting and receiving a high-frequency magnetic field through the high-frequency coil including a leg coil having any one of a linear shape and a shape separated from a central region; a tuning capacitor for adjusting surface current distribution of the high-frequency coil; and an operation port for applying a voltage to the high-frequency coil.

Description

A magnetic resonance image acquisition device having an oval cage body shape for improving the magnetic field uniformity and efficiency of a high-frequency body coil

The present invention improves the overall performance of a high-frequency coil in a magnetic resonance imaging system and selects a coil structure having an elliptical column shape to make a body coil of the maximum size that can wrap a human body in a cylindrical space, and the structure and It's about how it works.

Magnetic resonance imaging (MRI) is a high-frequency radiofrequency (RF) technique for the magnetization vector of nuclides (hydrogen, phosphorus, sodium, carbon, etc.) existing in the human body within a uniform main magnetic field. ) It is a technology that resonates a specific nuclide (hydrogen, etc.) by applying a pulse, receives a magnetic resonance signal generated by realigning the magnetization vectors in a vertical plane, and then reconstructs the image through a computer.

)의 곱에 비례하는, 라모어 주파수(Larmor Frequency)로도 알려진 각 주파수(

)로 세차운동을 한다(

). 피험체로부터 고주파 신호를 여기시키고 감지하기 위해서는 스핀에서 자화의 방향이 회전 자계(B₁ 필드)에 의해 교란되어야 하며, 회전 자계는 자화의 방향에 수직이며 송신 및 수신 고주파 코일에 의해 라모어 주파수로 진동한다. 고주파 코일은 인체의 생물학적 조직에 존재하는 수소 혹은 타핵종 원자를 여기시키는데 사용된다.A magnetic resonance image acquisition system generally acquires a magnetic resonance image of a subject by applying a high-frequency magnetic field to a subject, such as a human body, under a constant and uniform main magnetic field (B _{0 field).} The spins of protons and neutrons in tissues in the human body have nuclear magnetic moments, which _{are aligned in the B 0} field direction to create net magnetization (M). This spin depends on _{the strength of the B 0} field and the rate of magnetic rotation (

), which is proportional to the product of each frequency (

) to precess (

). In order to excite and sense a high-frequency signal from a subject, the direction of magnetization in the spin _{must be perturbed by a rotating magnetic field (B 1} field), which is perpendicular to the direction of magnetization and is brought to Lamore frequency by the transmitting and receiving high-frequency coils. vibrate High-frequency coils are used to excite hydrogen or other nuclides present in biological tissues of the human body.

The magnetic resonance imaging system is mainly used for diagnosis in hospitals, and a superconducting magnet is used to obtain a strong magnetic field. This superconducting magnet is installed inside. In this case, a high-pass cage coil is mainly used as the body high-frequency coil. The cage high-frequency coil generally has a cylindrical structure, with two circular short-circuit rings and a certain number of parallel and uniformly spaced conductor legs interconnecting the short-circuit rings. In general, the cage high-frequency coil is designed to have a circular short circuit and the legs are arranged at 360° at regular intervals. And this creates a uniform circularly polarized high-frequency magnetic field (B _{1 ) inside the high-frequency coil.}

In the oval body cage high frequency coil, the symmetry is broken compared with the cylindrical coil, and the performance of the high frequency coil deteriorates due to the change in the distance between the legs and the distance between the legs and the object to be photographed. In addition, the distance between the cage high-frequency coil and the high-frequency shield installed outside the cage changes depending on the angle, which may cause difficulties in tuning and matching the coil.

An embodiment of the present invention improves the uniformity and efficiency of a magnetic field by providing a high frequency coil having a branched shape in the central region of the coil and a plurality of operation ports capable of applying voltages having different magnitudes and phases to the high frequency coil An object of the present invention is to provide a magnetic resonance image acquisition device that can

On the other hand, the technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned are clearly to those of ordinary skill in the art to which the present invention belongs from the description below. can be understood

In the magnetic resonance image acquisition apparatus of the elliptical column shape provided to be perpendicular to the ellipses corresponding to the upper and lower surfaces of the virtual elliptical column and to be parallel to each other along the side of the virtual elliptical column according to an embodiment of the present invention, a plurality of high-frequency coils for transmitting and receiving a high-frequency magnetic field through a high-frequency coil including a leg coil having any one of a linear shape and a shape separated from the central region; a tuning capacitor for adjusting the surface current distribution of the high-frequency coil; and an operation port for applying a voltage to the high-frequency coil.

The high-frequency coil includes: a pair of end coils provided along the circumferential direction of the ellipse; and a leg coil connecting the pair of end coils. may include

The high frequency coil includes: a first high frequency coil including a pair of first end coils and a first leg coil having a linear shape; and a second high-frequency coil including a pair of second end coils and a second leg coil having a shape separated by a predetermined number in the central region.

The second leg coil may include: a region adjacent to the pair of second end coils has a linear shape; After being separated in an area separated by a preset distance from one end coil of the pair of second end coils, a preset number of integrated in an area separated by a preset distance from the other end coil of the pair of second end coils Branch leg coils may be included.

The preset number of branch leg coils includes a first branch leg coil and a second branch leg coil, and a distance between the first leg coil and the first branch leg coil and a distance between the first branch leg coil and the second branch leg coil and a distance between the second branch leg coil and the next first leg coil may be equal to each other.

The first high-frequency coil is provided in a first region, the second high-frequency coil is provided in a second region, the first region is a region between the minor axis of the ellipse and a region dividing line, and the second region is the a region between the long axis of the ellipse and the region dividing line, wherein the region dividing line passes through any one of a center of the ellipse and an edge of the ellipse; at a first angle with the minor axis of the ellipse; A second angle may be formed with the long axis of the ellipse.

A ratio of the first angle to the second angle may be 3 to 1 to 4 to 1.

The tuning capacitor may be provided between each end coil.

The operation port may include: a first operation port provided to be connected to two end coils adjacent to one side of a minor axis of the ellipse; a second operation port provided to be connected to two end coils adjacent to one side of the long axis of the ellipse; a third operation port provided to be connected to two end coils adjacent to the other side of the short axis of the ellipse; and a fourth operation port provided to be connected to two end coils adjacent to the other side of the long axis of the ellipse.

A voltage three times the voltage applied to the first operation port and the third operation port may be applied to the second operation port and the fourth operation port.

The voltage applied to the first operation port and the third operation port has a phase difference of 180°, the voltage applied to the second operation port and the fourth operation port has a phase difference of 180°, and the first operation port and the second operation port The voltage applied to the port may have a phase difference of 60°, and the voltage applied to the third operation port and the fourth operation port may have a phase difference of 60°.

The magnetic resonance image acquisition apparatus according to an embodiment of the present invention provides a high-frequency coil having a branched shape in a central region of the coil and a plurality of operation ports capable of applying voltages having different magnitudes and phases to the high-frequency coil. It is possible to improve the uniformity and efficiency of the magnetic field.

On the other hand, the effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description. will be able

1 is a view showing a state in which the magnetic resonance image acquisition system 10 is viewed from one side.
FIG. 2 is a perspective view schematically illustrating a state viewed from a direction adjacent to a long axis after the magnetic resonance image acquisition apparatus of FIG. 1 is erected.
3 is a diagram schematically illustrating a state in which the magnetic resonance image acquisition device having an elliptical columnar shape is viewed from the upper surface of the elliptical column according to an embodiment of the present invention.
FIG. 4 is a diagram schematically illustrating a state in which a region of interest, which is an inner region of the high-frequency coil of FIG. 3, is divided through a minor axis, a major axis, and a region dividing line of an ellipse.
5 is an exploded view of an apparatus for acquiring magnetic resonance images according to an embodiment of the present invention.
6 is an equivalent circuit diagram of passive elements (Lumped-element) showing the current flow of the magnetic resonance image acquisition device.
7 is a diagram schematically illustrating a ground breaker, a coaxial cable, an impedance matching circuit, and a transmission/reception switching circuit included in the magnetic resonance image acquisition device.

Other advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only this embodiment serves to complete the disclosure of the present invention, and to obtain common knowledge in the technical field to which the present invention pertains. It is provided to fully inform the possessor of the scope of the invention, and the invention is only defined by the scope of the claims.

Even if not defined, all terms (including technical or scientific terms) used herein have the same meaning as commonly accepted by common technology in the prior art to which this invention belongs. Terms defined by general dictionaries may be interpreted as having the same meaning as in the related description and/or in the text of the present application, and shall not be interpreted conceptually or excessively formally, even if the expression is not explicitly defined herein. won't

The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. As used herein, the singular also includes the plural unless specifically stated otherwise in the phrase. As used in the specification, 'comprise' and/or various conjugations of the verb, eg, 'comprising', 'comprising', 'comprising', 'comprising', etc., refer to the referenced composition, ingredient, component, A step, operation and/or element does not exclude the presence or addition of one or more other compositions, components, components, steps, operations and/or elements. As used herein, the term 'and/or' refers to each of the listed components or various combinations thereof.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings of the present specification.

1 is a view showing a state in which the magnetic resonance image acquisition system 10 is viewed from one side.

Referring to FIG. 1 , the magnetic resonance image acquisition system 10 includes _{a magnetic resonance image acquisition device 100 capable of transmitting and receiving a high-frequency magnetic field (B 1} magnetic field) for acquiring a magnetic resonance image, and a constant and uniform main magnetic field B ₀ field), the gradient magnetic field coil 300, which grasps the position of the subject by applying a gradient magnetic field to the main magnetic field to have a magnetic field of different strength depending on the position, and the main magnetic field magnet ( 200 ) and the gradient magnetic field coil 300 may include a high-frequency shield 400 that prevents coupling, and an additional high-frequency coil 500 that may be additionally provided adjacent to an area to acquire a magnetic resonance image. In this case, the main magnetic field magnet 200 , the gradient magnetic field coil 300 , and the high frequency shield 400 may be provided in a cylindrical shape.

In general, at 3.0 Tesla or lower magnetic field strength, the magnetic resonance image acquisition system 10 consists of a body transmission high-frequency coil that transmits high-frequency pulses to create a _{uniform B 1 field in the target volume.} Such a high-frequency coil _{should have high transmission efficiency along with high B 1} field uniformity, and the SAR should be lower than the SAR guidelines set by the FDA (or KFDA).

The magnetic resonance image acquisition apparatus 100 according to an embodiment of the present invention includes a high-frequency coil 1000 and acquires a magnetic resonance image in a region of interest, which is an inner region of the high-frequency coil 1000 .

The magnetic resonance image acquisition apparatus 100 is provided in the high frequency shield 400 and may be provided in the shape of an elliptical column, and it will be apparent that when viewed from one side, it is illustrated as shown in FIG. 1 . The user acquires the magnetic resonance image after positioning the object for which the magnetic resonance image is to be acquired in the inner region of the magnetic resonance image acquisition apparatus 100 .

The additional high-frequency coil 500 may be provided adjacent to a region to acquire a magnetic resonance image. For example, a magnetic resonance image may be acquired by transmitting a high-frequency magnetic field through a high-frequency coil included in the magnetic resonance image acquisition apparatus 100 and receiving it through an additional high-frequency coil 500 .

FIG. 2 is a perspective view schematically illustrating a state viewed from a direction adjacent to a long axis after the magnetic resonance image acquisition apparatus 100 according to an embodiment of the present invention is erected.

Referring to FIG. 2 , the magnetic resonance image acquisition apparatus 100 includes a high-frequency coil 1000 , a tuning capacitor 2000 , and an operation port 3000 .

The high-frequency coil 1000 is used to transmit, receive, or transmit/receive a high-frequency magnetic field. When the high-frequency coil 1000 transmits the high-frequency magnetic field, it is called a transmission mode, when it receives the high-frequency magnetic field is called a reception mode, and when it is transmitted/received is called a transmission/reception mode, and it is possible to change between each mode by a switching circuit to be started later.

The high frequency coil 1000 is provided to be perpendicular to the upper surface 31 and the bottom surface 32 of the virtual elliptical column 30 and parallel to each other along the side surface 33 of the virtual elliptical column. Each high frequency coil 1000 includes end coils 1110 and 1210 and leg coils 1120 and 1220 . The end coils 1110 and 1210 are provided as a pair at both ends of the high frequency coil 1000 along the circumferential direction of the upper surface 31 and the lower surface 32 of the virtual elliptical column 30 . The leg coils 1120 and 1220 are provided to connect the pair of end coils 1110 and 1210 to each other.

The high frequency coil 1000 includes a first high frequency coil 1100 and a second high frequency coil 1200 . The first high frequency coil 1100 includes a first end coil 1110 and a first leg coil 1120 , and the second high frequency coil 1200 includes a second end coil 1210 and a second leg coil 1220 . includes

The first end coil 1110 and the second end coil 1210 are provided along the circumferential direction of the ellipse forming the upper surface 31 and the lower surface 32 of the virtual elliptical column 30 . However, as shown, the circumferential length of each ellipse of the second end coil 1210 may be longer than the circumferential length of each ellipse of the first end coil 1110 .

The first leg coil 1120 is provided in a linear shape connecting the pair of first end coils 1110 to each other.

The second leg coils 1220 are provided in a shape separated by a preset number in the central region of the leg coil. Looking more closely at the shape of the second leg coil 1220 , the second leg coil 1220 has a linear shape in a region adjacent to each second end coil 1210 , whereas a preset shape in the central region of the leg coil 1220 . It has a shape separated by number. That is, after being separated in an area separated by a preset distance from one end coil of the pair of second end coils 1210 by a preset distance from the other end coil of the pair of second end coils 1210, in an area and a predetermined number of branch leg coils to be integrated.

For example, the predetermined number of branch leg coils in the second leg coil 1220 may be provided as two branch leg coils including the first branch leg coil 1221 and the second branch leg coil 1222 . have. That is, although the second leg coil 1220 of FIG. 2 is illustrated to include two branch leg coils 1221 and 1222 , the number of branch leg coils is provided as three or more according to the user's selection. It is possible.

In summary, the first high-frequency coil 1100 and the second high-frequency coil 1200 can be divided according to the shape of the leg coil, and the high-frequency coil including the first leg coil 1120 having a linear shape is used as the first high-frequency coil ( 1100), and a high frequency coil including a second leg coil 1220 having a plurality of branched leg coils is referred to as a second high frequency coil 1200 .

A tuning capacitor 2000 is provided between each end coil 1110 , 1210 . Through this, it can be operated as a high-pass coil. In addition, the shape of the magnetic resonance image acquisition device 100 can be used as a low-pass coil while maintaining the same shape. The capacitance value of the tuning capacitor 2000 is adjusted to have an optimal surface current distribution on the surface of the high frequency coil 1000 .

3 is a view schematically illustrating a state in which the magnetic resonance image acquisition apparatus 100 having an elliptical column shape is viewed from the direction of the upper surface 31 of the elliptical column according to an embodiment of the present invention.

Referring to FIG. 3 , the ellipse forming the upper surface 31 and the lower surface 32 of the elliptical column may be divided into four quadrants through a minor axis 23 and a major axis 24 . At this time, since each quadrant is symmetrical with respect to the minor axis 23 and the major axis 24 , hereinafter, the first quadrant among the four quadrants will be described as a reference.

As described above, the high frequency coil 1000 includes a first high frequency coil 1100 having a first leg coil 1120 and a second high frequency coil 1200 having a second leg coil 1220 .

The magnetic resonance image acquisition apparatus 100 includes a preset number of first high frequency coils 1100 and a preset number of second high frequency coils 1200 . For example, as shown in FIG. 3 , a total of 12 first high-frequency coils 1100 may be provided, three in each quadrant, and a total of four second high-frequency coils 1200, one in each quadrant. can However, it is obvious that the number of the first high frequency coil 1100 and the second high frequency coil 1200 can be adjusted according to the user's selection.

The first high frequency coil 1100 is provided adjacent to the minor axis 23 of the ellipse, and the second high frequency coil 1200 is provided adjacent to the major axis 24 of the ellipse. For example, when three first high-frequency coils 1100 and one second high-frequency coil 1200 are provided in each quadrant, all three first high-frequency coils 1100 are provided to be adjacent to the single axis 23 . and one second high frequency coil 1200 may be provided to be adjacent to the long axis 24 .

The second high frequency coil 1200 provided to be adjacent to the long axis 24 of the ellipse eliminates the non-uniformity _{of the B 1 magnetic field in the region adjacent to the long axis 24 .} In the case of the high frequency coil 1000 provided in the short axis 23 direction of the ellipse, the distance from the high frequency shield 400 is guaranteed, but in the case of the high frequency coil 1000 provided in the long axis 24 direction of the ellipse, the high frequency shield 400 A non-uniform magnetic field may be generated due to the close distance to . In the case of the second high frequency coil 1200 including a plurality of branch leg coils, the non-uniformity of the magnetic field may be reduced by generating a _{B 1 magnetic field in each branch leg coil.}

The operation port 3000 applies a voltage to the high-frequency coil. In this case, the operation port 3000 may be provided with a total of four operation ports along the circumference of the ellipse.

There are several problems when designing the high-frequency coil 1000 of the magnetic resonance image acquisition system 10 . The first is that when the high-frequency coil 1000 is located close to each other, a capacitance error due to the tuning capacitor 2000 occurs, making it very difficult to tune and match the high-frequency coil, thereby reducing the performance of the high-frequency coil 1000. . Second, for quadrature mode, when two ports with the same amplitude but a phase difference of 90° are operated, symmetry is broken and a distorted magnetic field is generated. The magnetic resonance image acquisition apparatus 100 according to an embodiment of the present invention provides four operation ports 3000 of the first operation port 3100 to the fourth operation port 3400 in order to solve this problem.

The first operation port 3100 is provided to be connected to the two first end coils 1110 closest to the upper end of the minor axis 23 of the ellipse in a region where the circumference of the ellipse and the upper end of the minor axis 23 of the ellipse contact each other. can The second operation port 3200 is connected to the two second end coils 1210 closest to the right end of the long axis 24 of the ellipse in a region where the circumference of the ellipse and the right end of the long axis 24 of the ellipse contact each other. may be provided. The third operation port 3300 is provided to be connected to the two first end coils 1110 closest to the lower end of the minor axis 23 of the ellipse in a region where the circumference of the ellipse and the lower end of the minor axis 23 of the ellipse contact each other. can The fourth operation port 3400 is connected to the two second end coils 1210 closest to the left end of the long axis 24 of the ellipse in a region where the circumference of the ellipse and the left end of the long axis 24 of the ellipse contact each other. can be provided.

According to an example using only two operation ports, any one of the first operation port 3100 and the third operation port 3300 and the second operation port 3200 and the fourth operation port 3400 Voltages having different magnitudes and phases may be applied to the high frequency coil 1000 through a total of two operation ports.

In addition, according to an example in which the four operation ports are used in mode, the voltage applied to the first operation port 3100 and the third operation port 3300 is applied to the second operation port 3200 and the fourth operation port 3400 . A voltage that is three times the magnitude of can be applied. In addition, the voltage applied to the first operation port 3100 and the third operation port 3300 has a phase difference of 180°, and the voltage applied to the second operation port 3200 and the fourth operation port 3400 is 180 Having a phase difference of °, the voltage applied to the first operation port 3100 and the second operation port 3200 has a phase difference of 60 °, and is applied to the third operation port 3300 and the fourth operation port 3400 The resulting voltage may be applied to have a phase difference of 60°.

For example, a voltage having a magnitude of V[V] and a phase of α[°] is applied to the first operation port 3100 , and a magnitude of 3V[V] and α+60 to the second operation port 3200 . A voltage having a phase of [°] is applied, and a voltage having a magnitude of V [V] and a phase of α + 180 [°] is applied to the third operation port 3300 , and the fourth operation port 3400 is A voltage having a magnitude of 3V[V] and a phase of α+240[°] may be applied.

However, the magnitude of the voltage at each operation port 3000 and the phase difference therebetween can be adjusted during actual magnetic resonance imaging, and can be electrically implemented with a high-frequency attenuator and a phase adjuster.

_{That is, a uniform B 1} magnetic field field is generated in the elliptical high-frequency coil 1000 through the four operation ports 3000 .

4 is a diagram schematically illustrating a state in which the region of interest 20, which is the inner region of the high-frequency coil 1000 of FIG. 3, is divided through the short axis 23, the long axis 24, and the region dividing line 25 of the ellipse. .

Referring to FIG. 4 , the region of interest 20 , which is an inner region of the high-frequency coil 1000 , may be divided into four quadrants through a minor axis 23 and a major axis 24 of the ellipse. Among them, the first quadrant includes a first region 21 and a second region 22 divided through a region dividing line 25 . In other words, the first region 21 refers to a region surrounded by the perimeter, the minor axis 23 and the region dividing line 25 of the ellipse, and the second region 22 is the perimeter, the long axis 24 and the region dividing line of the ellipse. (25) refers to the area surrounded by

The first high frequency coil 1100 provided to be adjacent to the single axis 23 is provided in the first area 21 , and the second high frequency coil 1200 provided to be adjacent to the single axis 24 is provided to the second area 22 . provided within.

In the first region 21 , the angle between the minor axis 23 and the region dividing line 25 is referred to as a first angle 26 , and in the second region 22 , the long axis 24 and the region dividing line 25 . ) is called the second angle 27 .

According to one embodiment, the ratio between the first angle 26 and the second angle 27 is 3 to 1 to 4 to 1, preferably a ratio of 3.5 to 1. However, at this time, the ratio can be adjusted to improve the performance of the high-frequency coil 1000 .

In addition, the first region 21 may be provided with three first high-frequency coils 1100 as shown, in this case, the angle between the minor axis 23 and the first high-frequency coil 1100, each of the first high-frequency coils An angle between 1100 and an angle between the first high-frequency coil 1100 and the region dividing line 25 may be provided as equal angles. However, according to the user's selection, it is also possible that the angles between them are provided at different angles instead of equal angles.

Information on the ratio between the first region 21 and the second region 22 in the first quadrant shown in FIG. 4 and the number of the first high frequency coil 1100 and the second high frequency coil 1200 included therein can be commonly applied to the second, third, and fourth quadrants by forming symmetry with respect to the minor axis 23 and the major axis 24 .

5 is an exploded view of the magnetic resonance image acquisition apparatus 100 according to an embodiment of the present invention.

Referring to FIG. 5 , according to an embodiment, the distance between the first leg coil 1120 and the first branch leg coil 1221 , the distance between the first branch leg coil 1221 and the second branch leg coil 1222 , and The distance between the second branch leg coil 1222 and the next first leg coil may be provided equal to each other. However, according to the user's selection, it is also possible that the distances between them are provided as different distances instead of the same distance.

A tuning capacitor 2000 is provided between each end coil. In this case, the end coil includes a first end coil 1110 and a second end coil 1210 . The tuning capacitor 2000 is provided to enable adjustment of capacitance in order to obtain resonance of the high-frequency coil 1000 at a desired frequency. That is, the capacitance value of the tuning capacitor 2000 is provided to have an optimal surface current distribution in each high frequency coil 1000 .

6 is an equivalent circuit diagram of passive elements (Lumped-element) showing the current flow of the magnetic resonance image acquisition apparatus 100 .

Referring to FIG. 6 , each current component may be expressed as the following equation.

은 타원의 장축(24)으로부터의 각도를 말한다. 즉, 각각의 고주파 코일(1000)에 흐르는 전류 성분은 고주파 코일(1000)의 배치 각도에 영향을 받는다. 도 4에서 상술한 바와 같이 제1 각도(26)와 제2 각도(27) 간의 비율은 3 대 1 내지 4 대 1을 갖으며, 바람직하게는 3.5 대 1의 비율을 갖는데,

은 이러한 조건에 맞춰 사용자의 선택에 따라 적절히 조절될 수 있다.At this time,

is the angle from the major axis 24 of the ellipse. That is, the current component flowing through each high-frequency coil 1000 is affected by the arrangement angle of the high-frequency coil 1000 . 4, the ratio between the first angle 26 and the second angle 27 is 3 to 1 to 4 to 1, preferably 3.5 to 1,

may be appropriately adjusted according to the user's selection in accordance with these conditions.

7 is a diagram schematically illustrating a ground breaker 4000 , a coaxial cable 5000 , an impedance matching circuit 6000 , and a transmission/reception switching circuit 7000 included in the magnetic resonance image acquisition apparatus 100 .

Referring to FIG. 7 , each operation port 3000 is connected to a coaxial cable 5000 through a ground breaker 4000 . The coaxial cable 5000 is connected to a transmission port or a reception port through an impedance matching circuit 6000 and a transmission/reception switching circuit 7000 .

The magnetic resonance image acquisition apparatus 1000 of the present invention can be operated by dividing it into high-frequency transmission and reception operations through the transmission/reception switching circuit 7000 . The configuration and effects of the ground breaker 4000, the coaxial cable 5000, and the impedance matching circuit 6000 correspond to known components in the technical field of the present invention, and thus a detailed description thereof will be omitted.

The magnetic resonance image acquisition apparatus 100 according to an embodiment of the present invention widens the region of interest 20 that can accommodate the portion to be acquired for the magnetic resonance image as much as possible, and increases the signal to noise ratio of the magnetic resonance image. , SNR) and to provide a high-frequency coil having an elliptical cage body shape for improving the uniformity of the magnetic field. To this end, input voltages having different magnitudes and phases are provided through the structure and arrangement of each high-frequency coil 1000 , capacitance control through the tuning capacitor 2000 , and each operation port 3000 .

Although the present invention has been described by way of examples above, the above examples are merely for explaining the spirit of the present invention and are not limited thereto. Those skilled in the art will understand that various modifications may be made to the above-described embodiments. The scope of the present invention is determined only through interpretation of the appended claims.

10: magnetic resonance image acquisition system
20: region of interest
21: first area
22: second area
23: shorten
24: long axis
25: area dividing line
26: first angle
27: second angle
30: virtual elliptical column
31: the upper surface of the virtual elliptical column
32: the lower surface of the virtual elliptical column
33: the side of the virtual elliptical column
100: magnetic resonance image acquisition device
200: magnetic field magnet
300: gradient magnetic field coil
400: high frequency shield
500: additional high-frequency coil
1000: high frequency coil
1100: first high-frequency coil
1110: first end coil
1120: first leg coil
1200: second high-frequency coil
1210: second end coil
1220: second leg coil
1221: first branch leg coil
1222: second branch leg coil
2000: tuning capacitor
3000: operation port
3100: first operation port
3200: second operation port
3300: third operation port
3400: fourth operation port
4000: Ground Breaker
5000: coaxial cable
6000: impedance matching circuit
7000: transmit/receive switching circuit

Claims (11)

In the magnetic resonance image acquisition device of the elliptical column shape provided to be perpendicular to the ellipses corresponding to the upper and lower surfaces of the virtual elliptical column and parallel to each other along the side of the virtual elliptical column,
a plurality of high-frequency coils for transmitting and receiving a high-frequency magnetic field through a high-frequency coil including a leg coil having any one of a linear shape and a shape separated from the central region;
a tuning capacitor for adjusting the surface current distribution of the high-frequency coil; and
Magnetic resonance image acquisition apparatus including an operation port for applying a voltage to the high-frequency coil. According to claim 1,
The high-frequency coil is:
a pair of end coils provided along the circumferential direction of the ellipse; and
Magnetic resonance image acquisition device comprising a leg coil connecting the pair of end coils. 3. The method of claim 2,
The high-frequency coil is:
a first high-frequency coil including a pair of first end coils and a first leg coil having a linear shape; and
A magnetic resonance image acquisition apparatus comprising a second high-frequency coil including a pair of second end coils and a second leg coil having a shape separated by a predetermined number in a central region. 4. The method of claim 3,
The second leg coil comprises:
a region adjacent to the pair of second end coils has a linear shape;
After being separated in an area separated by a preset distance from one end coil of the pair of second end coils, a preset number of integrated in an area separated by a preset distance from the other end coil of the pair of second end coils Magnetic resonance image acquisition device comprising a branched leg coil. 5. The method of claim 4,
The preset number of branch leg coils includes a first branch leg coil and a second branch leg coil,
The distance between the first leg coil and the first branch leg coil, the distance between the first branch leg coil and the second branch leg coil, and the distance between the second branch leg coil and the next first leg coil may be equal to each other. acquisition device. 6. The method of claim 5,
The first high-frequency coil is provided in a first area,
The second high-frequency coil is provided in a second region,
the first region is a region between the minor axis of the ellipse and a region dividing line;
the second region is a region between the long axis of the ellipse and the region dividing line;
The area dividing line is:
passing through any one of the center of the ellipse and the edge of the ellipse;
at a first angle with the minor axis of the ellipse;
A magnetic resonance image acquisition device forming a second angle with the long axis of the ellipse. 7. The method of claim 6,
A ratio of the first angle to the second angle is 3 to 1 to 4 to 1. 8. The method of claim 7,
The tuning capacitor is a magnetic resonance image acquisition device provided between each end coil. 9. The method of claim 8,
The operating port is:
a first operation port provided to be connected to two end coils adjacent to one side of the short axis of the ellipse;
a second operation port provided to be connected to two end coils adjacent to one side of the long axis of the ellipse;
a third operation port provided to be connected to two end coils adjacent to the other side of the short axis of the ellipse; and
Magnetic resonance image acquisition apparatus including a fourth operation port provided to be connected to two end coils adjacent to the other side of the long axis of the ellipse. 10. The method of claim 9,
A magnetic resonance image acquisition apparatus in which a voltage three times the voltage applied to the first and third operation ports is applied to the second operation port and the fourth operation port. 11. The method of claim 10,
The voltage applied to the first operation port and the third operation port has a phase difference of 180°,
The voltage applied to the second operation port and the fourth operation port has a phase difference of 180°,
The voltage applied to the first operation port and the second operation port has a phase difference of 60°,
A voltage applied to the third operation port and the fourth operation port has a phase difference of 60°.

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