Radio frequency coil, magnetic resonance probe and unilateral magnetic resonance imaging system

Abstract

The invention belongs to the technical field of magnetic resonance imaging, and aims to provide a radio frequency coil, a magnetic resonance probe and a unilateral magnetic resonance imaging system. The invention discloses a radio frequency coil used for unilateral magnetic resonance imaging, the radio frequency coil comprises a radio frequency coil body and a radio frequency coil support, the radio frequency coil body is arranged on the radio frequency coil support, the shape of the radio frequency coil body is a polygon, and any interior angle of the polygon is not 90 degrees; the magnetic resonance probe comprises the radio frequency coil. The unilateral magnetic resonance imaging system comprises the magnetic resonance probe. According to the invention, the accuracy of unilateral magnetic resonance detection can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic resonance imaging, and in particular relates to a radio frequency coil, a magnetic resonance probe and a unilateral magnetic resonance imaging system. Background Art

[0002] Magnetic resonance imaging technology has the advantages of being non-invasive, radiation-free, and capable of multi-parameter measurement. From the perspective of safety, accuracy, and stability, MRI detection technology is currently the best non-invasive detection technology for fatty liver. In order to reduce the size of MRI equipment and realize the mobile function of MRI equipment so that MRI equipment can complete bedside detection, during the MRI examination of fatty liver, a unilateral MRI system based on a unilateral magnet (non-uniform field magnet) can be used to achieve MRI.

[0003] However, in the process of using the prior art, the inventors found that the prior art has at least the following problems: Unilateral magnets are often accompanied by unsatisfactory excitation areas of unilateral MRI systems, resulting in low accuracy in liver testing using unilateral MRI systems. Specifically, in the process of using a unilateral MRI system for liver testing, a radio frequency magnetic field (referred to as the "B1 field") is generated in the target area (human liver) through a radio frequency coil. The B1 field is used to excite the nuclei in the target area, and the closer the direction of the B1 field is to 90 degrees from the B0 field (i.e., the main magnetic field), the greater the intensity of the excitation. However, since the uniform area of ​​the B0 field generated by the unilateral magnet used for liver testing is very small, and the equipotential lines of the magnetic field strength are distributed over a large range, the B1 field cannot select the target liver area for excitation, and a large amount of tissue outside the liver will also be excited, resulting in a decrease in the quality of magnetic resonance imaging and inaccurate liver test results. Summary of the invention

[0004] The present invention aims to solve the above technical problems at least to a certain extent. The present invention provides a radio frequency coil, a magnetic resonance probe and a unilateral magnetic resonance imaging system.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a radio frequency coil for unilateral magnetic resonance imaging, wherein the radio frequency coil comprises a radio frequency coil body and a radio frequency coil support, wherein the radio frequency coil body is arranged on the radio frequency coil support, and wherein the shape of the radio frequency coil body is a polygon, and any internal angle of the polygon is not 90 degrees.

[0006] In a possible design, the RF coil body is in a diamond shape.

[0007] In a possible design, the RF coil body is in a hexagonal shape.

[0008] In a possible design, the radio frequency coil body is wound with a flexible Litz wire and is fixedly disposed on the radio frequency coil support.

[0009] In a possible design, the RF coil body further includes a first capacitor, a second capacitor and a third capacitor, one end of the first capacitor serves as an input and output common end of the RF coil body, the other end of the first capacitor is electrically connected to one end of the third capacitor, the other end of the third capacitor serves as a ground end of the RF coil body, one end of the second capacitor is connected to the other end of the first capacitor, and the other end of the second capacitor is connected to one end of the third capacitor. In a possible design, the RF coil support is an arc-shaped plate, the RF coil body is laid on the concave side of the RF coil support, and the longest diagonal line of the RF coil body is arranged parallel to the central axis of the RF coil support.

[0010] In a second aspect, the present invention discloses a magnetic resonance probe, comprising a radio frequency coil as described in any one of the above.

[0011] In a possible design, the magnetic resonance probe further includes a unilateral magnet, and the radio frequency coil support is laid in the middle of one side of the unilateral magnet.

[0012] In a third aspect, the present invention discloses a unilateral magnetic resonance imaging system, comprising a magnetic resonance probe as described in any one of the above.

[0013] In one possible design, the unilateral magnetic resonance imaging system also includes a spectrometer, a first RF power amplifier, a transceiver converter, and a second RF power amplifier, wherein the input end of the first RF power amplifier and the output end of the second RF power amplifier are both electrically connected to the spectrometer, the output end of the first RF power amplifier is electrically connected to the first input end of the transceiver converter, the first output end of the transceiver converter is electrically connected to the RF input end of the RF coil body, the second input end of the transceiver converter is electrically connected to the RF output end of the RF coil body, and the second output end of the transceiver converter is electrically connected to the input end of the second RF power amplifier. The beneficial effects of the present invention are: The present invention discloses a radio frequency coil, a magnetic resonance probe and a unilateral magnetic resonance imaging system, which are beneficial to improving the accuracy of unilateral magnetic resonance detection. Specifically, in the present invention, since the shape of the radio frequency coil body is a polygon, and any internal angle of the polygon is not 90 degrees, the radio frequency coil of the present invention can solve the problem that the signal amount outside the liver area accounts for a large proportion when the existing square coil magnetic resonance system performs human liver magnetic resonance testing, thereby effectively improving the accuracy of liver magnetic resonance system detection, and can achieve higher accuracy of unilateral magnetic resonance detection without losing signal-to-noise ratio.

[0014] Other beneficial effects of the present invention will be further described in the specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a structural schematic diagram of an implementation method of a radio frequency coil body; Figure 2 is a structural schematic diagram of another embodiment of a radio frequency coil body; Figure 3 is a schematic diagram of the structure of a magnetic resonance probe; Figure 4 It is a schematic diagram of the magnetic field distribution of the radio frequency coil body and the unilateral magnet; Figure 5 It is a block diagram of a unilateral magnetic resonance imaging system. DETAILED DESCRIPTION

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be briefly introduced below in combination with the drawings and the description of the embodiments or the prior art. Obviously, the following description of the structure of the drawings is only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0017] Embodiment 1: like Figures 1 to 4 As shown, this embodiment discloses a radio frequency coil for unilateral magnetic resonance imaging, wherein the radio frequency coil comprises a radio frequency coil body 1 and a radio frequency coil support 2, wherein the radio frequency coil body 1 is disposed on the radio frequency coil support 2, wherein the radio frequency coil body 1 is in the shape of a polygon, and any internal angle of the polygon is not 90 degrees. In this embodiment, the radio frequency coil support 2 is used to fix the radio frequency coil body 1.

[0018] It should be noted that the RF coil body 1 is used to transmit and receive RF signals to the measured tissues such as the liver of the human body. In the implementation process, the RF pulses emitted by the RF coil body 1 are used to excite the nuclear spins in the measured human tissues, and then receive the echo signals returned by the nuclear spins.

[0019] In this embodiment, by adjusting the shape of the RF coil body 1, the shape of the RF coil body 1 is a polygon, and any internal angle of the polygon is not 90 degrees, so that the angle between the B1 field generated by the RF coil body 1 and the B0 field outside the target area becomes smaller, and only a lower component of the B1 field is orthogonal to the B0 field, and the excitation intensity of the nucleus is greatly reduced; at the same time, it can be ensured that the B0 field and the B1 field in the target area are orthogonal, and the B1 field intensity is not reduced. In this case, the proportion of the signal in the target test area in the total signal can be greatly increased, thereby improving the accuracy of the detection results when performing magnetic resonance imaging detection on the human body tissue under test.

[0020] Specifically, refer to Figure 4 ,according to Figure 4 In Figure (a), the half height a of the RF coil body 1 is set to 22.5 cm, and the half width b is 56.25 cm. At this time, the angle between the B0 field and the B1 field is 22°, and the B1 field component B1'=Sin(22°)*B1≈0.374*B1, which is orthogonal to the B0 field; according to Figure 4 In the figure (b), the half height a of the RF coil body 1 is set to 25 cm, and the half width b is 50.63 cm. At this time, the angle between the B0 field and the B1 field is 26°, and the B1 field component B1'=Sin(26°)*B1≈0.438*B1, which is orthogonal to the B0 field. Based on the above case, it can be seen that based on the shape setting of the RF coil body 1 in this embodiment, only the lower component of the B1 field is orthogonal to the B0 field.

[0021] During implementation, the ratio of the width to the height of the RF coil body 1 can be controlled to reduce the angle between the direction of the coil magnetic field B1 and the direction of the unilateral magnet magnetic field B0, thereby reducing the excitation intensity of the RF coil in the non-target area.

[0022] Specifically, in one embodiment, Figure 1 As shown, the shape of the radio frequency coil body 1 is a rhombus.

[0023] In another embodiment, if Figure 2 As shown, the shape of the radio frequency coil body 1 is hexagonal.

[0024] In this embodiment, the RF coil body 1 is wound with a flexible Litz wire and fixedly arranged on the RF coil support 2. It should be noted that the flexible Litz wire is composed of multiple strands of thin wires. Winding the RF coil body 1 with the flexible Litz wire can effectively reduce the skin effect in the RF signal, help improve the efficiency of the RF coil, and reduce energy loss; in addition, the flexible Litz wire has better flexibility than the traditional single-strand wire, which is convenient for adjusting the shape of the RF coil body 1. After the RF coil body 1 is fixedly arranged on the RF coil support 2, the flexible Litz wire can reduce the damage to the structure of the RF coil body 1 due to external force or vibration, increase the durability and stability of the RF coil body 1, and thus ensure the stability of the imaging performance.

[0025] In this embodiment, the RF coil body 1 further includes a first capacitor C1, a second capacitor C2 and a third capacitor C3, one end of the first capacitor C1 serves as the input and output common end of the RF coil body 1, the other end of the first capacitor C1 is electrically connected to one end of the third capacitor C3, the other end of the third capacitor C3 serves as the ground end of the RF coil body 1, one end of the second capacitor C2 is connected to the other end of the first capacitor C1, and the other end of the second capacitor C2 is connected to one end of the third capacitor C3. It should be noted that the RF coil body 1 itself can be regarded as an inductor, which has an inductive characteristic. In this embodiment, the third capacitor C3 can form a parallel resonant circuit with the RF coil body 1, and the parallel resonant circuit can achieve resonance at a specific frequency and can amplify the electrical signal at a specific frequency. The third capacitor C3 is used to adjust the resonant frequency to meet specific circuit requirements; the first capacitor C1 and the second capacitor C2 are parallel resonant circuits for impedance matching, that is, the setting of the first capacitor C1 and the second capacitor C2 can be used to adjust the impedance in the parallel resonant circuit to ensure better transmission of electrical signals.

[0026] Furthermore, in this embodiment, the RF coil support 2 is an arc-shaped plate, the RF coil body 1 is laid on the concave side of the RF coil support 2 , and the longest diagonal line of the RF coil body 1 is arranged parallel to the central axis of the RF coil support 2 .

[0027] It should be noted that, in this embodiment, the radio frequency coil support 2 is a curved plate, which can make the radio frequency coil fit the human body better.

[0028] In addition, in this embodiment, since the shape of the RF coil body 1 is a polygon, and any internal angle of the polygon is not 90 degrees, the RF coil body 1 has a longest diagonal line with the longest length and the only number; at the same time, the RF coil support 2 adopts an arc plate, so that the RF coil support 2 has a central axis. In the implementation process, the longest diagonal line of the RF coil body 1 is arranged parallel to the central axis of the RF coil support 2, thereby further reducing the component orthogonal to the B0 field in the B1 field generated by the RF coil.

[0029] The present invention discloses a radio frequency coil for a unilateral magnetic resonance imaging system, which can improve the problem of low detection accuracy of human tissue due to non-ideal excitation area, and is conducive to improving the accuracy of unilateral magnetic resonance detection. Specifically, in this embodiment, since the shape of the radio frequency coil body 1 is a polygon, and any internal angle of the polygon is not 90 degrees, the radio frequency coil of this embodiment can solve the problem that the signal amount outside the liver area accounts for a large proportion when the existing square coil magnetic resonance system performs human liver magnetic resonance testing, thereby effectively improving the accuracy of liver magnetic resonance system detection, and can achieve higher accuracy of unilateral magnetic resonance detection without losing signal-to-noise ratio.

[0030] Embodiment 2: This embodiment discloses a magnetic resonance probe, including the radio frequency coil described in any one of the embodiments 1. Figure 3 and Figure 4 As shown, the magnetic resonance probe further includes a unilateral magnet 3 , and the radio frequency coil support 2 is laid in the middle of one side of the unilateral magnet 3 .

[0031] It should be noted that the unilateral magnet 3 is used to generate a static magnetic field to polarize the nuclear spins in the human tissue being measured, thereby generating a magnetic resonance signal.

[0032] It should also be noted that the working process, working details and technical effects of the magnetic resonance probe provided in this embodiment 2 can be found in embodiment 1 and will not be described in detail here.

[0033] Embodiment 3: Based on Embodiment 1 or 2, this embodiment discloses a unilateral magnetic resonance imaging system, including the magnetic resonance probe described in any one of Embodiment 2. Figure 5As shown, the unilateral magnetic resonance imaging system also includes a spectrometer, a first RF power amplifier, a transceiver converter and a second RF power amplifier, the input end of the first RF power amplifier and the output end of the second RF power amplifier are both electrically connected to the spectrometer, the output end of the first RF power amplifier is electrically connected to the main input end of the transceiver converter, the input and output common end of the transceiver converter is electrically connected to the input and output common end of the RF coil body 1, and the main output end of the transceiver converter is electrically connected to the input end of the second RF power amplifier.

[0034] Specifically, in this embodiment, the spectrometer can control the operation of the entire unilateral magnetic resonance imaging system. During the operation of the unilateral magnetic resonance imaging system, the spectrometer is used to generate a radio frequency pulse signal and transmit the radio frequency pulse signal to the radio frequency coil body 1 through the first radio frequency power amplifier and the transceiver converter, and is also used to receive the echo signal collected by the radio frequency coil body 1 through the second radio frequency power amplifier. In addition, the spectrometer can also realize the processing of the echo signal and image reconstruction. Among them, the first radio frequency power amplifier is used to amplify the radio frequency signal emitted by the spectrometer to ensure that there is enough power to excite the nuclear spins in the human tissue under test; the second radio frequency power amplifier is used to amplify the echo signal received from the radio frequency coil body 1; the transceiver converter is used to realize the switching between the sending and receiving of radio frequency signals. In the excitation stage, the transceiver converter allows the radio frequency signal to be transmitted to the radio frequency coil body 1, and in the receiving stage, the transceiver converter amplifies the echo signal obtained from the human tissue under test through the second radio frequency power amplifier, and finally transmits it to the spectrometer.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A radio frequency coil for unilateral magnetic resonance imaging, characterized in that: The radio frequency coil comprises a radio frequency coil body (1) and a radio frequency coil support (2); the radio frequency coil body (1) is arranged on the radio frequency coil support (2); the radio frequency coil body (1) is in the shape of a polygon, and any internal angle of the polygon is not 90 degrees.

2. The radio frequency coil according to claim 1, characterized in that: The radio frequency coil body (1) is in the shape of a rhombus.

3. The radio frequency coil according to claim 1, characterized in that: The radio frequency coil body (1) is in the shape of a hexagon.

4. The radio frequency coil according to claim 1, characterized in that: The radio frequency coil body (1) is wound with a flexible Litz wire and is fixedly arranged on the radio frequency coil support (2).

5. The radio frequency coil according to claim 1, characterized in that: The radio frequency coil body (1) further comprises a first capacitor (C1), a second capacitor (C2) and a third capacitor (C3); one end of the first capacitor (C1) serves as an input and output common end of the radio frequency coil body (1); the other end of the first capacitor (C1) is electrically connected to one end of the third capacitor (C3); the other end of the third capacitor (C3) serves as a ground end of the radio frequency coil body (1); one end of the second capacitor (C2) is connected to the other end of the first capacitor (C1); and the other end of the second capacitor (C2) is connected to one end of the third capacitor (C3).

6. The radio frequency coil according to claim 1, characterized in that: The radio frequency coil support (2) is an arc-shaped plate, the radio frequency coil body (1) is laid on the concave side of the radio frequency coil support (2), and the longest diagonal line of the radio frequency coil body (1) is arranged parallel to the central axis of the radio frequency coil support (2).

7. A magnetic resonance probe, characterized in that: Comprising a radio frequency coil as claimed in any one of claims 1 to 6.

8. The magnetic resonance probe according to claim 7, characterized in that: The magnetic resonance probe further comprises a unilateral magnet (3), and the radio frequency coil support (2) is laid in the middle of one side of the unilateral magnet (3).

9. A unilateral magnetic resonance imaging system, characterized in that: Comprising a magnetic resonance probe as claimed in any one of claims 7 to 8.

10. A unilateral magnetic resonance imaging system according to claim 9, characterized in that: The unilateral magnetic resonance imaging system further comprises a spectrometer, a first radio frequency power amplifier, a transceiver converter and a second radio frequency power amplifier, wherein the input end of the first radio frequency power amplifier and the output end of the second radio frequency power amplifier are both electrically connected to the spectrometer, the output end of the first radio frequency power amplifier is electrically connected to the first input end of the transceiver converter, the first output end of the transceiver converter is electrically connected to the radio frequency input end of the radio frequency coil body (1), the second input end of the transceiver converter is electrically connected to the radio frequency output end of the radio frequency coil body (1), and the second output end of the transceiver converter is electrically connected to the input end of the second radio frequency power amplifier.

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