阅读说明：本技术 多核射频接收线圈结构、多核射频接收装置及设备 (Multi-core radio frequency receiving coil structure, multi-core radio frequency receiving device and equipment ) 是由 郑海荣 李烨 李楠 杜凤 陈巧燕 刘新 于 2021-08-30 设计创作，主要内容包括：本申请涉及核磁共振成像,提供了一种多核射频接收线圈结构、多核射频接收装置及设备,包括：第一接收线圈,用于接收第一种类的核的MR弛豫信号；第二接收线圈,用于接收第二种类或第三种类的核的MR弛豫信号,所述第二接收线圈和所述第一接收线圈层叠设置；其中,所述交错中心位于所述第二接收线圈在所述第一接收线圈方向上的垂直投影内,以实现所述第二接收线圈产生的磁场和所述第一接收线圈产生的磁场为正交分布,使得所述第一接收线圈和所述第二接收线圈之间去耦。不受限于射频线圈的通道数和线圈的尺寸。三种核素信号的射频表面接收线圈方案不局限于～(19)F,～(23)Na,～(31)P核素的成像,可以扩展到任何感兴趣的核素。(The application relates to nuclear magnetic resonance imaging, and provides a multi-core radio frequency receiving coil structure, a multi-core radio frequency receiving device and equipment, which comprise: a first receive coil for receiving MR relaxation signals of a first kind of nuclei; a second receiving coil for receiving MR relaxation signals of nuclei of a second kind or a third kind, the second receiving coil and the first receiving coil being arranged in a stack; wherein the staggered center is located in a vertical projection of the second receiving coil in the direction of the first receiving coil to realize that the magnetic field generated by the second receiving coil and the magnetic field generated by the first receiving coil are distributed orthogonally, so that the first receiving coil and the second receiving coil are decoupled. And is not limited by the number of channels of the radio frequency coil and the size of the coil. The RF surface receiving coil scheme for three nuclear species signals is not limited to 19 F, 23 Na, 31 P-nuclide imaging, extendable toWhich nuclear species of interest.)

1. A multi-core radio frequency receive coil structure, comprising:

a first receive coil for receiving MR relaxation signals of a first species of nuclei, said first receive coil comprising an interleaved center with interleaved current direction located in the middle of said first receive coil;

a second receiving coil for receiving MR relaxation signals of nuclei of a second kind or a third kind, the second receiving coil and the first receiving coil being arranged in a stack;

wherein the staggered center is located in a vertical projection of the second receiving coil in the direction of the first receiving coil to realize that the magnetic field generated by the second receiving coil and the magnetic field generated by the first receiving coil are distributed orthogonally, so that the first receiving coil and the second receiving coil are decoupled.

2. The multi-core radio frequency receive coil structure of claim 1, wherein the first receive coil is a butterfly structure and the second receive coil is a ring structure.

3. The multi-core radio frequency receiving coil structure according to claim 1, wherein the first receiving coil includes an input side line segment in a "C" shape, an intermediate line segment in an "X" shape, and an output side line segment, the input side line segment and the output side line segment are symmetrically disposed, the intermediate line segment includes a first line segment and a second line segment that are staggered and not connected to form the staggered center, and both ends of the first line segment are connected to a first end of the input side line segment and a second end of the output side line segment, respectively, and both ends of the second line segment are connected to a second end of the input side line segment and a first end of the output side line segment, respectively.

4. The multi-nuclei radio frequency receive coil structure of any of claims 1 to 3, wherein at least one first capacitance for tuning to match MR relaxation signals of nuclei of the first kind is connected to the first receive coil.

5. The multi-nuclei radio frequency receive coil structure of claim 1 or 2, wherein at least one second capacitance for tuning MR relaxation signals matching nuclei of the second kind and at least one third capacitance for tuning MR relaxation signals matching nuclei of the third kind are connected to the second receive coil;

wherein the resonance of the second receive coil on the MR relaxation signals of the second kind of nuclei or of the third kind of nuclei is achieved by switching in or short-circuiting said third capacitance.

6. A multi-nuclear radio frequency receiving device comprising the multi-nuclear radio frequency receiving coil structure of any one of claims 1 to 5, the multi-nuclear radio frequency receiving device further comprising:

a first driving circuit, coupled to the first receiving coil, for providing a first driving signal to the first receiving coil, so that the first receiving coil receives and outputs MR relaxation signals of a first kind of nuclei;

the first protection circuit is connected with the first receiving coil and used for controlling the first receiving coil to inhibit operation when the transmitting coil of the first receiving coil works;

a second driving circuit, coupled to the second receiving coil, for providing a second driving signal to the second receiving coil, so that the second receiving coil receives and outputs MR relaxation signals of nuclei of a second kind or a third kind;

the second protection circuit is connected with the second receiving coil and used for controlling the second receiving coil to inhibit operation when the transmitting coil of the second receiving coil works;

a tuning circuit, coupled to the second receive coil, for controlling the second receive coil to switch between receiving the MR relaxation signals of the second species of nuclei and the MR relaxation signals of the third species of nuclei.

7. The multi-core radio frequency receiving device according to claim 6, wherein the first driving circuit comprises a first driving interface for receiving the first driving signal, a first inductor, a first diode and a first tuning capacitor, an anode of the first diode is connected with an anode of the first driving interface, a cathode of the first diode is connected with a cathode of the first driving interface, the first tuning capacitor is connected with the first diode in parallel and in series with the first receiving coil, and an anode and/or a cathode of the first driving interface is connected with the first inductor in series;

the second driving circuit comprises a second driving interface used for accessing the second driving signal, a second inductor, a second diode and a second tuning capacitor, wherein the anode of the second diode is connected with the anode of the second driving interface, the cathode of the second diode is connected with the cathode of the second driving interface, the second tuning capacitor is connected with the second diode in parallel and is connected with the second receiving coil in series, and the anode and/or the cathode of the second driving interface are connected with the second inductor in series.

8. The multi-core radio frequency receiving device according to claim 6 or 7, further comprising a first output interface, a third tuning capacitor connected in series to the first receiving coil, a second output interface, and a fourth tuning capacitor connected in series to the second receiving coil, wherein a positive electrode and a negative electrode of the first output interface are respectively connected to two ends of the third tuning capacitor, and the first output interface is configured to output the MR relaxation signals of the first kind of cores; and the anode and the cathode of the second output interface are respectively connected to two ends of the fourth tuning capacitor, and the second output interface is used for outputting the MR relaxation signals of the second kind or the third kind of nuclei.

9. The multi-core radio frequency receiving device according to claim 8, wherein the first protection circuit includes a third diode, a third inductor and a first protection interface, an anode of the third diode is connected to an anode of the first output interface, a cathode of the third diode is connected to a cathode of the first output interface, the anode and/or cathode of the first protection interface is connected in series with the third inductor, and the first protection interface is configured to control the first receiving coil to access a protection signal to drive the third diode to conduct to short-circuit the first output interface when a transmitting coil of the first receiving coil is in operation;

the second protection circuit comprises a fourth diode, a fourth inductor and a second protection interface, the anode of the fourth diode is connected with the anode of the second output interface, the cathode of the fourth diode is connected with the cathode of the second output interface, the anode and/or cathode of the second protection interface are connected in series with the fourth inductor, the second protection interface is used for controlling the second receiving coil to be switched in to protect signal driving to conduct so as to short circuit the second output interface when the transmitting coil works.

10. The multi-core radio frequency receiving device according to claim 6 or 7, wherein the tuning circuit includes a tuning interface and a fifth tuning capacitor, the fifth tuning capacitor is connected in series with the second receiving coil, an anode and a cathode of the tuning interface are respectively connected to two ends of the fifth tuning capacitor, and the tuning interface is connected or not connected to a tuning signal so as to short or not short the fifth tuning capacitor, so as to control the second receiving coil to switch between receiving the MR relaxation signal of the second kind of core and the MR relaxation signal of the third kind of core.

11. A magnetic resonance imaging apparatus comprising the multi-nuclear radio frequency receiving device of any one of claims 6 to 10.

Technical Field

The application belongs to the technical field of Nuclear Magnetic Resonance Imaging (NMRI), and particularly relates to a multi-core radio frequency receiving coil structure, a multi-core radio frequency receiving device and Magnetic Resonance Imaging equipment.

Background

At present, the simultaneous acquisition of multiple nuclear species SIGNALs is of great significance for nuclear magnetic resonance quantitative imaging, and the inherent low SIGNAL-to-NOISE RATIO (SNR) of non-H (hydrogen) nuclear species imaging puts higher requirements on the development of multi-nuclear imaging technology and hardware. In the design scheme of the multi-core radio frequency coil, the multi-resonance of the coil is realized mainly by two main schemes of a single structure and a combined structure. The single structure, which is primarily a single coil unit that achieves two or more resonant frequencies, can be easily extended to a multi-channel array design by maintaining isolation between different cores, splitting the frequencies by adding a frequency trap circuit on each loop of the coil, creating a double or triple resonance. The frequency-approaching double-resonance radio frequency coil is realized by utilizing the switching function of the diode. But the quality and signal-to-noise ratio of the coil is degraded due to losses caused by the insertion of the notch element.

In schemes based on two or more independent physical coil structures to achieve multi-nuclear resonance, mainly including geometric decoupling structures and nested combinations, geometric decoupling can enable two separate coil adjustments in two different spaces to be assigned to each desired frequency, which allows for freely extending the selection of nuclei to multiple nuclei without losing the signal-to-noise ratio of any selected nuclei, since each coil is a single tuned coil. Extending this multi-structure, single-channel coil structure to a multi-channel array design is quite difficult and requires coil swapping at the time of measurement. In designs using nested coils, handling the coupling of two coil systems is a major task, with a significant impact on the quality of the signal. This coupling can be controlled by modifying the distance or arrangement between two coils and between each channel within a coil to avoid performance degradation. However, the ability to control the coupling by adjusting the distance between the inner and outer coils may be limited by the size of the body and the limited space available within the magnet bore. Most simultaneous protocols are limited to dual-core acquisition or independent imaging of nuclides with separate coils.

Disclosure of Invention

The application aims to provide a multi-core radio frequency receiving coil structure, a multi-core radio frequency receiving device and magnetic resonance imaging equipment, and aims to solve the problems of poor signal quality and large volume of an existing combined resonance structure.

A first aspect of an embodiment of the present application provides a multi-core radio frequency receiving coil structure, including:

a first receive coil for receiving MR relaxation signals of a first species of nuclei, said first receive coil comprising an interleaved center with interleaved current direction located in the middle of said first receive coil;

a second receiving coil for receiving MR relaxation signals of nuclei of a second kind or a third kind, the second receiving coil and the first receiving coil being arranged in a stack;

wherein the staggered center is located in a vertical projection of the second receiving coil in the direction of the first receiving coil to realize that the magnetic field generated by the second receiving coil and the magnetic field generated by the first receiving coil are distributed orthogonally, so that the first receiving coil and the second receiving coil are decoupled.

In one embodiment, the first receiving coil is a butterfly structure, and the second receiving coil is a ring structure.

In one embodiment, the first receiving coil includes an input side line segment in a "C" shape, an intermediate line segment in an "X" shape, and an output side line segment, the input side line segment and the output side line segment are symmetrically disposed, the intermediate line segment includes a first line segment and a second line segment that are staggered and not connected to form the staggered center, two ends of the first line segment are respectively connected to a first end of the input side line segment and a second end of the output side line segment, and two ends of the second line segment are respectively connected to a second end of the input side line segment and a first end of the output side line segment.

In one embodiment, at least one first capacitance for tuning the MR relaxation signals matching the first species of nuclei is connected to the first receiving coil.

In one embodiment, at least one second capacitance for tuning MR relaxation signals matching nuclei of the second kind and at least one third capacitance for tuning MR relaxation signals matching nuclei of the third kind are connected to the second receiving coil;

wherein the resonance of the second receive coil on the MR relaxation signals of the second kind of nuclei or of the third kind of nuclei is achieved by switching in or short-circuiting said third capacitance.

A second aspect of the embodiments of the present application provides a multi-core radio frequency receiving device, including the above multi-core radio frequency receiving coil structure, where the multi-core radio frequency receiving device further includes:

a first driving circuit, coupled to the first receiving coil, for providing a first driving signal to the first receiving coil, so that the first receiving coil receives and outputs MR relaxation signals of a first kind of nuclei;

the first protection circuit is connected with the first receiving coil and used for controlling the first receiving coil to inhibit operation when the transmitting coil of the first receiving coil works;

a second driving circuit, coupled to the second receiving coil, for providing a second driving signal to the second receiving coil, so that the second receiving coil receives and outputs MR relaxation signals of nuclei of a second kind or a third kind;

the second protection circuit is connected with the second receiving coil and used for controlling the second receiving coil to inhibit operation when the transmitting coil of the second receiving coil works;

a tuning circuit, coupled to the second receive coil, for controlling the second receive coil to switch between receiving the MR relaxation signals of the second species of nuclei and the MR relaxation signals of the third species of nuclei.

In one embodiment, the first driving circuit comprises a first driving interface for receiving the first driving signal, a first inductor, a first diode and a first tuning capacitor, wherein an anode of the first diode is connected with an anode of the first driving interface, a cathode of the first diode is connected with a cathode of the first driving interface, the first tuning capacitor is connected with the first diode in parallel and is connected with the first receiving coil in series, and the anode and/or the cathode of the first driving interface is connected with the first inductor in series;

the second driving circuit comprises a second driving interface used for accessing the second driving signal, a second inductor, a second diode and a second tuning capacitor, wherein the anode of the second diode is connected with the anode of the second driving interface, the cathode of the second diode is connected with the cathode of the second driving interface, the second tuning capacitor is connected with the second diode in parallel and is connected with the second receiving coil in series, and the anode and/or the cathode of the second driving interface are connected with the second inductor in series.

In one embodiment, the MR relaxation signal generating device further comprises a first output interface, a third tuning capacitor connected in series to the first receiving coil, a second output interface, and a fourth tuning capacitor connected in series to the second receiving coil, wherein a positive electrode and a negative electrode of the first output interface are respectively connected to two ends of the third tuning capacitor, and the first output interface is configured to output an MR relaxation signal of the first kind of nuclei; and the anode and the cathode of the second output interface are respectively connected to two ends of the fourth tuning capacitor, and the second output interface is used for outputting the MR relaxation signals of the second kind or the third kind of nuclei.

In one embodiment, the first protection circuit includes a third diode, a third inductor and a first protection interface, an anode of the third diode is connected with an anode of the first output interface, a cathode of the third diode is connected with a cathode of the first output interface, the anode and/or cathode of the first protection interface is connected in series with the third inductor, and the first protection interface is configured to control the first receiving coil to access a protection signal to drive the third diode to conduct to short-circuit the first output interface when the transmitting coil of the first receiving coil operates;

the second protection circuit comprises a fourth diode, a fourth inductor and a second protection interface, the anode of the fourth diode is connected with the anode of the second output interface, the cathode of the fourth diode is connected with the cathode of the second output interface, the anode and/or cathode of the second protection interface are connected in series with the fourth inductor, the second protection interface is used for controlling the second receiving coil to be switched in to protect signal driving to conduct so as to short circuit the second output interface when the transmitting coil works.

In one embodiment, the tuning circuit includes a tuning interface and a fifth tuning capacitor, the fifth tuning capacitor is connected in series to the second receiving coil, a positive electrode and a negative electrode of the tuning interface are respectively connected to two ends of the fifth tuning capacitor, and the tuning interface is connected or not connected to a tuning signal so as to short or not short the fifth tuning capacitor, so as to control the second receiving coil to switch between receiving the MR relaxation signals of the second kind of nuclei and the MR relaxation signals of the third kind of nuclei.

A third aspect of the embodiments of the present application provides a resonance imaging apparatus, including the above multi-nuclear radio frequency receiving device.

Compared with the existing double-tuning radio frequency array coil structure and the three-ring independent three-resonance structure, the multi-core radio frequency receiving coil structure, the multi-core radio frequency receiving device and the magnetic resonance imaging equipment have the advantages that the radio frequency receiving coil structure supporting three-nuclide imaging is provided, the free switching of the working frequencies of the three nuclides is realized on the basis of the combination of the two independent coil structures, the three-nuclide nuclear magnetic resonance imaging is realized, the size is small, and the miniaturization of products is facilitated; in addition, in a structure with orthogonal magnetic fields, decoupling between different coils is realized, the signal quality is good, and the method can be extended to any nuclear species of interest.

Drawings

Fig. 1 is a schematic structural diagram of a multi-core radio frequency receiving coil structure provided in an embodiment of the present application;

FIG. 2 is a schematic diagram of an example circuit of a first receiving coil in a multi-core radio frequency receiving device according to an embodiment of the present disclosure;

FIG. 3 is an exemplary circuit schematic diagram of a second receiving coil in a multi-core radio frequency receiving device according to an embodiment of the present application;

fig. 4 is a timing chart of driving voltages of a multi-core rf receiving device according to an embodiment of the present disclosure;

fig. 5(a) illustrates a multi-core rf receiving apparatus according to an embodiment of the present application¹⁹F、²³S11 parameter waveform for Na channel operation;

fig. 5(b) illustrates a multi-core rf receiving apparatus according to an embodiment of the present application³¹S11 parameter waveform for P channel operation.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, refer to an orientation or positional relationship illustrated in the drawings for convenience in describing the present application and to simplify description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more, and "several" means one or more unless specifically limited otherwise.

Fig. 1 shows a schematic structural diagram of a multi-core radio frequency receiving coil structure provided in an embodiment of the present application, and for convenience of description, only parts related to the embodiment are shown, which are detailed as follows:

a multi-core radio frequency receive coil structure includes a first receive coil 100 and a second receive coil 200. The first receiving coil 100 is used for receiving a Magnetic Resonance (MR) relaxation signal of a first kind of nuclei, the first receiving coil 100 includes a staggered center 101 with a staggered current direction, which is located in the middle of the first receiving coil 100; a second receiving coil 200 for receiving MR relaxation signals of the second kind or the third kind of nuclei, the second receiving coil 200 and the first receiving coil 100 being arranged in a stack; wherein, the interleaving center 101 is located in the vertical projection of the second receiving coil 200 in the direction of the first receiving coil 100 to realize that the magnetic field generated by the second receiving coil 200 and the magnetic field generated by the first receiving coil 100 are distributed orthogonally, so that the first receiving coil 100 and the second receiving coil 200 are decoupled.

The directions of the two independent receiving coils 100 and 200 connected to the driving signals TD1/TD2 are different, and are in an approximately orthogonal relationship, so that the currents passing through most of the conductive paths on the two coils are in an orthogonal relationship, and therefore, the magnetic fields generated by the first receiving coil 100 and the second receiving coil 200 are also in an orthogonal distribution, thereby realizing electromagnetic decoupling, improving the signal-to-noise ratio, and improving the quality of magnetic resonance imaging. The first receiving coil 100 and the second receiving coil 200 are stacked, and radio frequency receiving of three nuclear species imaging can be realized, compared with a three-turn independent three-resonance structure, the volume is much smaller, and miniaturization of a product is facilitated. The first kind of nucleus may be²³Na, the second type of core may be¹⁹F, the firstThe three kinds of nuclei may be³¹P, of course, may be¹H、¹⁴N、¹³C、³⁹K、¹⁷O or¹²⁹X, the user can adjust the length of the two coils or add other tuning devices depending on the resonant frequency to which the different species are matched.

In one embodiment, the first receiving coil 100 has a butterfly structure and the second receiving coil 200 has a ring structure. As shown in fig. 1, the first receiving coil 100 receives the driving signal TD2 from the left side, and the second receiving coil 200 receives the driving signal TD1 from the upper side, so that the current directions of the two coils are approximately orthogonal to each other at the same time. In general, capacitors may be provided on both coils to tune and match the resonance frequency of the MR relaxation signal of the corresponding nuclear species. Alternatively, the second receiving coil 200 has a rectangular structure or a circular structure.

In one embodiment, the first receiving coil 100 includes an input side line segment 102 in a "C" shape, an intermediate line segment 103 in an "X" shape, and an output side line segment 104, the input side line segment 102 is disposed symmetrically with the output side line segment 104, the intermediate line segment 103 includes a first line segment 103a and a second line segment 103b forming a staggered center 101, which are staggered and not connected, and two ends of the first line segment 103a are respectively connected with a first end of the input side line segment 102 and a second end of the output side line segment 104, and two ends of the second line segment 103b are respectively connected with a second end of the input side line segment 102 and a first end of the output side line segment 104. The corners of the input side line segment 102 in the "C" shape and the output side line segment 104 symmetrically arranged with the input side line segment 102 may be right angles or rounded corners, which is not limited specifically.

Optionally, at least one first capacitance for tuning the MR relaxation signals matching the first type of nuclei is connected to the first receiving coil 100. In this example, four first capacitors C1, C2, C3 and C4 are connected in series to the first receiving coil 100, wherein the capacitors C1 and C3 are connected in series to the input-side segment 102 and located on opposite sides of the input port of the input-side segment 102, and the capacitors C2 and C4 are respectively disposed on the input port and the output port of the input-side segment 102 and located between the input port and the positive and negative poles of the output port. Optionally, at least one of the capacitances C1, C2, C3, C4 is an adjustable capacitance to adjust the resonant frequency of the first receiving coil 100.

In one embodiment, at least one second capacitance for tuning the MR relaxation signals matching the second kind of nuclei and at least one third capacitance for tuning the MR relaxation signals matching the third kind of nuclei are connected to the second receiving coil 200. In this example, four second capacitors, C5, C6, C7 and C9, are connected in series to the second receiving coil 200, wherein the capacitors C6 and C9 are connected in series to opposite sides of the input port of the second receiving coil 200, and the capacitors C5 and C7 are respectively disposed between the input port and the output port of the second receiving coil 200 and between the positive and negative poles of the input port and the output port. The third capacitance C8 for tuning the MR relaxation signal matching the third kind of nuclei is used, in particular, by switching in or short-circuiting the third capacitance C8 to achieve that the second receiving coil 200 resonates at the MR relaxation signal of the second kind of nuclei or the MR relaxation signal of the third kind of nuclei. Optionally, at least one of the capacitances C5, C6, C7, C9 is an adjustable capacitance to adjust the resonance frequency of the second receiving coil 200.

A second aspect of the embodiments of the present application provides a multi-core radio frequency receiving device, which includes the above-mentioned multi-core radio frequency receiving coil structure, and further includes a first driving circuit 11, a first protection circuit 12, a second driving circuit 13, a second protection circuit 14, and a tuning circuit 15.

A first driving circuit 11 and a first receiving coil 100, for providing a first driving signal TD2 to the first receiving coil 100, so that the first receiving coil 100 receives and outputs MR relaxation signals of the first kind of nuclei; a first protection circuit 12 and a first receiving coil 100 for controlling the first receiving coil 100 to inhibit operation when the transmitting coil thereof is operated; a second driving circuit 13 and a second receiving coil 200 for providing a second driving signal TD1 to the second receiving coil 200 so that the second receiving coil 200 receives and outputs MR relaxation signals of the second kind or the third kind of nuclei; a second protection circuit 14 and a second receiving coil 200 for controlling the second receiving coil 200 to inhibit operation when the transmitting coil thereof is operated; a tuning circuit 15 and a second receiving coil 200 for controlling the second receiving coil 200 to switch between receiving the MR relaxation signals of the second kind of nuclei and the MR relaxation signals of the third kind of nuclei.

It can be understood that the driving signal TD1/TD2 is switched on when the transmitting coil stops working, so as to avoid damage caused by simultaneous working of the receiving coil and the transmitting coil; and when the transmitting coil works, the output of the receiving coil is closed, specifically, the anode and the cathode of the output port are directly short-circuited.

In one embodiment, the first driving circuit 11 includes a first driving interface 112 for receiving the first driving signal TD2, a first inductor L1, a first diode D1, and a first tuning capacitor C2, an anode of the first diode D1 is connected to an anode of the first driving interface 112, a cathode of the first diode D1 is connected to a cathode of the first driving interface 112, the first tuning capacitor C2 is connected in parallel to the first diode D1 and is connected in series to the first receiving coil 100, and the anode and/or the cathode of the first driving interface 112 is connected in series to the first inductor L1;

the second driving circuit 13 includes a second driving interface 131 for receiving a second driving signal TD1, a second inductor L2, a second diode D3, and a second tuning capacitor C5, an anode of the second diode D3 is connected to an anode of the second driving interface 131, a cathode of the second diode D3 is connected to a cathode of the second driving interface 131, the second tuning capacitor C5 is connected to the second diode D3 in parallel and in series with the second receiving coil 200, and the anode and/or the cathode of the second driving interface 131 is connected to the second inductor L2 in series. Optionally, the first inductor L1 and the second inductor L2 may be one or two inductors, and if one inductor is connected in series with the positive pole or the negative pole of the driving interface, and if two inductors are connected in series with the positive pole and the negative pole of the driving interface at the same time, so as to function as an anti-interference input. Optionally, the first driving interface 112 and the second driving interface 131 are coaxial line interfaces, and the inner conductor and the outer conductor of the coaxial line are respectively the anode and the cathode of the driving interface, and the coaxial line is used to transmit the driving signal, which is beneficial to improving the anti-interference capability and improving the signal quality.

In one embodiment, the MR relaxation signal generating device further includes a first output interface Na _ Rx, a third tuning capacitor C4 connected in series to the first receiving coil 100, a second output interface F _ Rx, and a fourth tuning capacitor C7 connected in series to the second receiving coil 200, wherein a positive electrode and a negative electrode of the first output interface Na _ Rx are respectively connected to two ends of the third tuning capacitor C4, and the first output interface Na _ Rx is configured to output an MR relaxation signal of a first kind of core; the positive pole and the negative pole of the second output interface F _ Rx are respectively connected to two ends of the fourth tuning capacitor C7, and the second output interface F _ Rx is used for outputting the MR relaxation signals of the second kind or the third kind of nuclei. First output interface Na _ Rx and second output interface F _ Rx are coaxial line interfaces, and the inner conductor and the outer conductor of coaxial line are output interface's positive pole and negative pole respectively, utilize the coaxial line to transmit drive signal, are favorable to improving the interference killing feature, promote signal quality.

In one embodiment, the first protection circuit 12 includes a third diode D2, a third inductor L3, and a first protection interface 121, an anode of the third diode D2 is connected to an anode of the first output interface Na _ Rx, a cathode of the third diode D2 is connected to a cathode of the first output interface Na _ Rx, an anode and/or a cathode of the first protection interface 121 is connected in series with the third inductor L3, and the first protection interface 121 is configured to control the first receiving coil 100 to access the first protection signal TR2 to drive the third diode D2 to be turned on when the transmitting coil of the first receiving coil 100 operates, so as to short-circuit the first output interface Na _ Rx and turn off the first receiving coil 100, so as to protect itself and the subsequent circuits;

the second protection circuit 14 includes a fourth diode D4, a fourth inductor L4 and a second protection interface 141, an anode of the fourth diode D4 is connected to an anode of the second output interface F _ Rx, a cathode of the fourth diode D4 is connected to a cathode of the second output interface F _ Rx, an anode and/or a cathode of the second protection interface 141 is connected in series to the fourth inductor L4, and the second protection interface 141 is configured to control the second receiving coil 200 to access the first protection signal TR1 to drive the fourth diode D4 to be turned on when the transmitting coil of the second receiving coil 200 works, so as to short-circuit the second output interface F _ Rx and turn off the output of the second receiving coil 200, thereby protecting the second receiving coil and the subsequent circuits.

Optionally, the third inductor L3 and the fourth inductor L4 may be one or two inductors, and if one inductor is connected in series to the positive pole or the negative pole of the output interface, and if two inductors are connected in series to the positive pole and the negative pole of the output interface at the same time, so as to function as an anti-interference input. Optionally, the first protection interface 121 and the second protection interface 141 are coaxial line interfaces, the inner conductor and the outer conductor of the coaxial line are respectively the anode and the cathode of the protection interface, and the coaxial line is used for transmitting the driving signal, so that the anti-interference capability is improved, and the signal quality is improved.

In one embodiment, the tuning circuit 15 includes a tuning interface 151 and a fifth tuning capacitor C8, the fifth tuning capacitor C8 is connected in series with the second receiving coil 200, the positive pole and the negative pole of the tuning interface 151 are respectively connected to two ends of the fifth tuning capacitor C8, and the tuning interface 151 is connected or not connected to the tuning signal to short or not short the fifth tuning capacitor C8, so as to control the second receiving coil 200 to switch between receiving the MR relaxation signal of the second kind of core and the MR relaxation signal of the third kind of core. Optionally, the tuning interface 151 is a coaxial line interface, and the tuning signal P _ Rx is a voltage signal, which is equivalent to short-circuiting or not short-circuiting the fifth tuning capacitor C8 when the coaxial line interface is connected or not connected with a voltage; in another embodiment, the tuning interface 151 may be a switching element, such as a relay or the like.

As shown in fig. 2 and 3 in conjunction with fig. 4, in fig. 4, Tx represents the power supply of each control circuit in the transmitting state; rx indicates the input voltage of each circuit when the coil is in the receiving state.

The first driving signal TD2 and the second driving signal TD1 have the same operation timing, and when the first type of nuclear MR transmitting coil operates, in order to protect the first receiving coil 100, the first protection signal TR2 needs to be 5V, and the third diode D2 is turned on, so that the first output interface Na _ Rx is short-circuited. In order to ensure that the first receiving coil 100 resonates at the frequency of the MR relaxation signals of the first type of nuclei, the first drive signal TD2 is-30V and the first guard signal TR2 is-30V in the receiving state. At this time, the first diode D1 and the third diode D2 are not conducted, and tuning and matching are realized through capacitors C1, C2, C3 and C4.

Similar to the operating principle of the first receiving coil 100, when the second kind of nuclear MR transmitting coil operates, in order to protect the second receiving coil 200, the first protection signal TR1 needs to be equal to 5V, the fourth diode D4 is turned on, and the second output interface F _ Rx is short-circuited to achieve the protection effect. When the second receiving coil 200 is operated, the first protection signal TR1 is-30V, the fourth diode D4 is non-conductive, the second drive signal TD1 is-30V, the second diode D3 is non-conductive, and the capacitors C5, C6, C7, C8, and C9 participate in MR relaxation signal resonance of the second kind of nuclei. When the second driving signal TD1 and the first driving signal TD2 are equal to 5V, the capacitor C2 is short-circuited, and only the residual capacitors C1, C3 and C4 in the first receiving coil 100 participate in resonance; therefore, the resonance frequency of the first receiving coil 100 has shifted at this time. When the second drive signal TD1 is 5V and the tuning signal P _ Rx is-30V, the capacitor C8 is short-circuited in the second receiving coil 200, the capacitors C5, C6, C7, and C9 participate in the resonance of the MR relaxation signal of the third type of nuclei, and the MR relaxation signal of the third type of nuclei resonates when the capacitors are not at the MR relaxation signal resonance point of the first and second types of nuclei.

A third aspect of the embodiments of the present application provides a resonance imaging apparatus, including the above multi-nuclear radio frequency receiving device.

The array coil structure provided by the application is subjected to experimental test, and the test result shows that¹⁹F、²³Na、³¹Each channel of P realizes better tuning and matching¹⁹F、²³When Na works simultaneously, the matching of each channel is less than-15 dB, as shown by curves S11 and S44 in FIG. 5 (a); when in use³¹When the P channel works, as shown by a curve S33 in fig. 5(b), matching is nearly-20 dB, and experimental results prove that the three-core radio frequency receiving coil scheme provided by the application is feasible, and the realization of the three-core radio frequency receiving coil scheme is realized¹⁹F、²³Na、³¹P resonates.

Compared with the existing double-tuning radio frequency array coil structure and the three-ring independent three-resonance structure, the multi-core radio frequency receiving coil structure, the multi-core radio frequency receiving device and the magnetic resonance imaging equipment have the advantages that the radio frequency receiving coil structure supporting three-nuclide imaging is provided, the free switching of the working frequencies of the three nuclides is realized on the basis of the combination of the two independent coil structures, the three-nuclide nuclear magnetic resonance imaging is realized, the size is small, and the miniaturization of products is facilitated; in addition, in a structure with orthogonal magnetic fields, decoupling between different coils is realized, the signal quality is good, and the method can be extended to any nuclear species of interest.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.