Dual-channel radio frequency coil and design method thereof

Abstract

The invention discloses a dual-channel radio frequency coil and a design method thereof, and relates to the technical field of magnetic resonance imaging, and the dual-channel radio frequency coil comprises a solenoid coil and a saddle-shaped coil located outside the solenoid coil. The solenoid coil comprises a spiral ring coil winding and a lead component; the spiral ring coil winding comprises a plurality of spiral ring coils; the saddle-shaped coil comprises a first saddle-shaped coil group, a second saddle-shaped coil group and a matching circuit; the matching circuit comprises a tuning component, a first coil assembly, a first tuning network capacitor, a first balun, a matching excitation element, a second balun, a second tuning network capacitor and a second coil assembly which are connected in sequence; and the first coil assembly is connected with the first saddle-shaped coil assembly. The signal receiving capability and the imaging uniformity can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of magnetic resonance imaging, and in particular to a dual-channel radio frequency coil and a design method thereof. Background Art

[0002] Currently, magnetic resonance imaging (MRI) technology has been widely used in the field of medical imaging. Traditional high-field and medium-field MRI systems can achieve high image resolution and signal-to-noise ratio. However, in some specific application scenarios, such as portable imaging equipment, resource-constrained environments, and occasions with higher patient safety requirements (such as avoiding the heating effect caused by high field strength), ultra-low field magnetic resonance imaging (ULF-MRI) has become an important alternative. Ultra-low field MRI has the advantages of low field strength and high safety, but it also faces some key challenges: weak signal strength: due to the low magnetic field strength of the ultra-low field, the magnetic resonance signal generated is very weak, and it is difficult to obtain sufficient signal strength, resulting in poor image quality; large noise interference: in the ultra-low field environment, the signal-to-noise ratio is usually low, and the receiving coil is easily affected by external electromagnetic interference and system noise, thereby reducing the imaging effect; matching and tuning difficulties: traditional single-channel RF coils are difficult to achieve accurate matching and tuning under low field strength conditions, resulting in low signal transmission efficiency and unsatisfactory imaging effects.

[0003] Existing single-channel or traditional coil designs have weak signal reception capabilities and imaging uniformity in low field strength environments. Summary of the invention

[0004] The purpose of this application is to provide a dual-channel radio frequency coil and a design method thereof, which can effectively improve signal receiving capability and imaging uniformity in a low field strength environment.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides a dual-channel radio frequency coil, comprising a solenoid coil and a saddle coil located outside the solenoid coil.

[0007] The solenoid coil comprises a spiral ring coil winding and a wire component; the spiral ring coil winding comprises a plurality of spiral ring coils connected in sequence; the wire component consists of an upper horizontal wire, a lower horizontal wire, a solenoid vertical wire, a spiral coil upper capacitor element and a spiral coil middle and lower excitation element; one end of the upper horizontal wire is connected to one end of the spiral coil upper capacitor element, and the other end of the upper horizontal wire is connected to the solenoid vertical wire; the other end of the spiral coil upper capacitor element is connected to the first spiral ring coil; the lower horizontal wire end is connected to one end of the spiral coil middle and lower excitation element, and the other end of the lower horizontal wire is connected to the solenoid vertical wire; the other end of the spiral coil middle and lower excitation element is connected to the last spiral ring coil; the spiral coil upper capacitor element is used to adjust the resonant frequency of the solenoid coil;

[0008] The saddle coil comprises a first saddle coil group, a second saddle coil group and a matching circuit; the first saddle coil group and the second saddle coil group are arranged in a mirror image;

[0009] The matching circuit includes a tuning component, a first coil component, a first tuning network capacitor, a first balun, a matching excitation element, a second balun, a second tuning network capacitor and a second coil component connected in sequence; the first coil component is connected to the first saddle coil group; the tuning component includes a tuning capacitor and a matching inductor; the tuning component, the first tuning network capacitor and the second tuning network capacitor are used to adjust the resonant frequency of the saddle coil.

[0010] Optionally, the spiral ring coil winding includes a first spiral ring coil group, a second spiral ring coil group, a third spiral ring coil group, a fourth spiral ring coil group and a fifth spiral ring coil group; the first spiral ring coil group includes 3 turns of the first spiral ring coil; the second spiral ring coil group includes 2 turns of the second spiral ring coil; the third spiral ring coil group includes 18 turns of the third spiral ring coil; the fourth spiral ring coil group includes 2 turns of the fourth spiral ring coil; the fifth spiral ring coil group includes 2 turns of the fifth spiral ring coil.

[0011] Optionally, the turn distances between the first spiral toroidal coils, the turn distances between the second spiral toroidal coils, the turn distances between the third spiral toroidal coils, the turn distances between the fourth spiral toroidal coils, and the turn distances between the fifth spiral toroidal coils are 1 cm or 0.5 cm.

[0012] Optionally, first radii of the first spiral loop coil, the second spiral loop coil, the third spiral loop coil, the fourth spiral loop coil and the fifth spiral loop coil are equal.

[0013] Optionally, the first radius is 0.12 m.

[0014] Optionally, the first saddle coil group includes an upper left semicircular coil, a lower left semicircular coil, a left front vertical wire and a left rear vertical wire; two endpoints of the upper left semicircular coil are respectively connected to one end of the left front vertical wire and one end of the left rear vertical wire; two endpoints of the lower left semicircular coil are respectively connected to the other end of the left front vertical wire and the other end of the left rear vertical wire;

[0015] The second saddle coil group comprises an upper right semicircular coil, a lower right semicircular coil, a right front vertical wire and a right rear vertical wire; two endpoints of the upper right semicircular coil are respectively connected to one end of the right front vertical wire and one end of the right rear vertical wire; two endpoints of the lower right semicircular coil are respectively connected to the other end of the right front vertical wire and the other end of the right rear vertical wire;

[0016] The upper left semicircular coil and the lower left semicircular coil are arranged in parallel with the upper right semicircular coil and the lower right semicircular coil.

[0017] Optionally, the second radii of the first circular ring and the second circular ring are equal; the first circular ring is composed of an upper left semicircular ring coil and a lower left semicircular ring coil; the second circular ring is composed of an upper right semicircular ring coil and a lower right semicircular ring coil.

[0018] Optionally, the second radius is 0.13 m.

[0019] Optionally, the height of the saddle-shaped coil is 0.24 m.

[0020] In a second aspect, the present application provides a design method for a dual-channel radio frequency coil, comprising:

[0021] The genetic algorithm is used to optimize the geometric parameters of the solenoid to obtain the optimal geometric parameters of the solenoid; the geometric parameters of the solenoid include the radius of the spiral ring coil, the turn distance between the spiral ring coils and the number of windings of the spiral ring coil winding; the number of windings of the spiral ring coil winding is the number of the spiral ring coils;

[0022] The dual-channel radio frequency coil described in the first aspect is prepared based on the optimal solenoid geometric parameters.

[0023] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0024] The main problems of existing single-channel or traditional coils include: 1) Poor reception uniformity: The magnetic field distribution of single-channel coils is uneven, resulting in large variations in signal strength in the image, affecting the diagnostic effect. 2) Inaccurate matching: Due to poor matching between the coil and the system, the energy transmission efficiency is low, resulting in severe signal attenuation. 3) Insufficient noise suppression: The existing coil design is sensitive to environmental noise and cannot effectively isolate and suppress external interference.

[0025] Based on the above problems, the present application provides a dual-channel radio frequency coil and a design method thereof, which realizes circular polarization field distribution through a saddle-shaped coil, so that the magnetic field is evenly covered in the horizontal and vertical directions, significantly improving the uniformity and sensitivity of signal reception, and effectively reducing the dead zone and uneven area in signal reception, which is particularly suitable for ultra-low field magnetic resonance imaging (ULF-MRI) environment; by precisely adjusting the tuning capacitor and matching inductor, the dual-channel radio frequency coil can accurately resonate at the Larmor frequency, and the adjusted matching circuit ensures the optimal impedance matching of the coil, minimizes signal reflection and energy loss, thereby improving the overall signal transmission efficiency and imaging quality. The imaging capability of the system under low field strength is improved through the synergistic effect of the above-mentioned devices, and the circular polarization design and matching circuit adjustment enable the dual-channel coil to effectively adapt to low-field magnetic resonance imaging, providing clearer and higher-resolution images than traditional single-channel coils. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A schematic diagram of the overall structure of a dual-channel radio frequency coil provided in one embodiment of the present application;

[0028] Figure 2 A schematic diagram of the structure of a solenoid coil provided in one embodiment of the present application;

[0029] Figure 3 A schematic diagram of the structure of a saddle coil provided in one embodiment of the present application;

[0030] Figure 4 A schematic diagram of a matching circuit provided in an embodiment of the present application.

[0031] Reference numerals:

[0032] Saddle coil—1, solenoid coil—2, first spiral ring coil group—3, second spiral ring coil group—4, third spiral ring coil group—5, fourth spiral ring coil group—6, fifth spiral ring coil group—7, matching circuit—8, upper horizontal wire—9, lower horizontal wire—10, solenoid vertical wire—11, upper capacitor element of spiral coil—12, lower middle excitation element of spiral coil—13, upper left half ring coil—1 4, upper right semicircular ring coil - 15, matching excitation element - 16, lower left semicircular ring coil - 17, lower right semicircular ring coil - 18, left front vertical wire - 19, right front vertical wire - 20, left rear vertical wire - 21, right rear vertical wire - 22, first coil assembly - 23, second coil assembly - 24, first balun - 25, second balun - 26, first tuning network capacitor - 27, tuning component - 28, second tuning network capacitor - 29. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0034] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0035] In an exemplary embodiment, Figure 1 As shown, a dual-channel radio frequency coil is provided, comprising a solenoid coil 2 and a saddle coil 1 located outside the solenoid coil 2 .

[0036] like Figure 2As shown, the solenoid coil 2 includes a spiral ring coil winding and a wire component; the spiral ring coil winding includes a plurality of spiral ring coils connected in sequence; the wire component is composed of an upper horizontal wire 9, a lower horizontal wire 10, a solenoid vertical wire 11, a spiral coil upper capacitor element 12 and a spiral coil middle and lower excitation element 13; one end of the upper horizontal wire 9 is connected to one end of the spiral coil upper capacitor element 12, and the other end of the upper horizontal wire 9 is connected to the solenoid vertical wire 11; the other end of the spiral coil upper capacitor element 12 is connected to the first spiral ring coil; the end of the lower horizontal wire 10 is connected to one end of the spiral coil middle and lower excitation element 13, and the other end of the lower horizontal wire 10 is connected to the solenoid vertical wire 11; the other end of the spiral coil middle and lower excitation element 13 is connected to the last spiral ring coil; the spiral coil upper capacitor element 12 is used to adjust the resonant frequency of the solenoid coil 2.

[0037] The lower excitation element 13 in the solenoid coil is an excitation current source device, and an S-parameter discrete edge port can be used during simulation.

[0038] The spiral ring coil winding includes a first spiral ring coil group 3, a second spiral ring coil group 4, a third spiral ring coil group 5, a fourth spiral ring coil group 6 and a fifth spiral ring coil group 7; the first spiral ring coil group 3, the second spiral ring coil group 4, the third spiral ring coil group 5, the fourth spiral ring coil group 6 and the fifth spiral ring coil group 7 are connected in sequence from top to bottom. The first spiral ring coil group 3 includes 3 turns of the first spiral ring coil; the second spiral ring coil group 4 includes 2 turns of the second spiral ring coil; the third spiral ring coil group 5 includes 18 turns of the third spiral ring coil; the fourth spiral ring coil group 6 includes 2 turns of the fourth spiral ring coil; the fifth spiral ring coil group 7 includes 2 turns of the fifth spiral ring coil.

[0039] The first spiral ring coil group 3 and the fifth spiral ring coil group 7 are respectively connected to the upper capacitor element 12 of the spiral coil and the lower excitation element 13 in the middle of the spiral coil. The outside of the upper capacitor element 12 of the spiral coil and the lower excitation element 13 in the middle of the spiral coil are respectively connected to one end of the upper horizontal wire 9 and one end of the lower horizontal wire 10.

[0040] The turns between the first spiral toroidal coils, the turns between the second spiral toroidal coils, the turns between the third spiral toroidal coils, the turns between the fourth spiral toroidal coils, and the turns between the fifth spiral toroidal coils are 1 cm or 0.5 cm. In a specific embodiment, the turns between the first spiral toroidal coils may be 1 cm, the turns between the second spiral toroidal coils may be 0.5 cm, the turns between the third spiral toroidal coils may be 1 cm, the turns between the fourth spiral toroidal coils may be 0.5 cm, and the turns between the fifth spiral toroidal coils may be 1 cm.

[0041] The first radii of the first spiral loop coil, the second spiral loop coil, the third spiral loop coil, the fourth spiral loop coil and the fifth spiral loop coil are equal. Preferably, the first radius is 0.12 m.

[0042] like Figure 3 As shown, the saddle coil 1 includes a first saddle coil group 1, a second saddle coil group 1 and a matching circuit 8; the first saddle coil group 1 and the second saddle coil group 1 are arranged in a mirror image.

[0043] The first saddle coil group 1 includes an upper left semicircular coil 14, a lower left semicircular coil 17, a left front vertical wire 19 and a left rear vertical wire 21; the two endpoints of the upper left semicircular coil 14 are respectively connected to one end of the left front vertical wire 19 and one end of the left rear vertical wire 21; the two endpoints of the lower left semicircular coil 17 are respectively connected to the other end of the left front vertical wire 19 and the other end of the left rear vertical wire 21.

[0044] The second saddle coil group 1 includes an upper right semicircular coil 15, a lower right semicircular coil 18, a right front vertical wire 20 and a right rear vertical wire 22; the two ends of the upper right semicircular coil 15 are respectively connected to one end of the right front vertical wire 20 and one end of the right rear vertical wire 22; the two ends of the lower right semicircular coil 18 are respectively connected to the other end of the right front vertical wire 20 and the other end of the right rear vertical wire 22. The upper left semicircular coil 14 and the lower left semicircular coil 17 are arranged in parallel with the upper right semicircular coil 15 and the lower right semicircular coil 18.

[0045] The second radius of the first and second rings is equal; the first ring is composed of an upper left semicircular ring coil 14 and a lower left semicircular ring coil 17; the second ring is composed of an upper right semicircular ring coil 15 and a lower right semicircular ring coil 18. Preferably, the second radius is 0.13m, and the height of the saddle coil 1 is 0.24m.

[0046] like Figure 4As shown, the matching circuit 8 includes a tuning component 28, a first coil component 23, a first tuning network capacitor 27, a first balun 25, a matching excitation element 16, a second balun 26, a second tuning network capacitor 29 and a second coil component 24 connected in sequence; the first coil component 23 is connected to the first saddle coil group 1; the tuning component 28 includes a tuning capacitor Ct and a matching inductor Lm; the tuning component 28, the first tuning network capacitor 27 and the second tuning network capacitor 29 are used to adjust the resonant frequency of the saddle coil 1.

[0047] It should be noted that the matching excitation element 16 is an excitation current source device, and an S-parameter discrete edge port can be used during simulation.

[0048] The lower end of the left front vertical wire 19 is connected to the first coil assembly 23, the first tuning network capacitor 27, the first balun 25, the matching excitation element 16, the second balun 26, the second tuning network capacitor 29 and the second coil assembly 24 in sequence to achieve precise tuning and impedance matching of the dual-channel RF coil, ensuring the optimal working state of the system at the target Larmor frequency.

[0049] In an exemplary embodiment, the present application provides a dual-channel radio frequency coil design method, characterized in that the dual-channel radio frequency coil design method includes the following steps 1 to 3:

[0050] Step 1: Using a genetic algorithm, the geometric parameters of the solenoid are optimized to obtain the optimal geometric parameters of the solenoid; the geometric parameters of the solenoid include the radius of the spiral ring coil, the turn spacing between the spiral ring coils and the number of windings of the spiral ring coil winding; the number of windings of the spiral ring coil winding is the number of spiral ring coils; based on the optimal solenoid geometric parameters, the above-mentioned dual-channel RF coil is prepared. The turn spacing between the spiral ring coils refers to the distance between adjacent spiral ring coil groups.

[0051] The computer software Pycharm is used to optimize the geometric parameters of the solenoid. The geometric parameters of the solenoid are optimized according to the objective function (such as maximizing signal strength and improving uniformity). This step uses the genetic algorithm (GA) to automatically adjust the radius, coil spacing and number of windings of the solenoid to obtain the best magnetic field distribution.

[0052] The fitness in the genetic algorithm is the above objective function, and the individuals in the population are the radius, coil spacing and number of windings of the solenoid. The magnetic field strength B1 is obtained by Biot-Savart theorem based on the radius, number of coil turns and number of windings of the solenoid, thereby obtaining the signal strength and uniformity. The objective function and the main parameters involved are as follows:

[0053] Main parameters:

[0054] Radius r: The radius of the helical toroidal coil, which affects the concentration of the magnetic field.

[0055] Coil spacing d: The distance between adjacent spiral ring coil groups, which affects the uniformity of the coil.

[0056] Number of windings n: The total number of turns of the coil, that is, the number of windings of the spiral toroidal coil winding, affects the magnetic field strength.

[0057] Known quantities: initial geometric parameter settings, optimization objectives.

[0058] Unknown quantity: optimal geometric parameter configuration.

[0059] Fitness: Minimize the fitness value to solve the optimal solenoid geometric parameters.

[0060] The objective function is calculated as follows:

[0061] fitness=ξ sim -ppm

[0062]

[0063] Where, fitness is the fitness; ξ sim is the signal strength, which is used to describe the simulation results of a certain signal; ppm is the uniformity (parts per million, parts per million difference), which is used to measure the change of the maximum and minimum values ​​of the magnetic field strength relative to the average value, and is usually used to express unevenness or error; ω0 is the resonant frequency, which is related to the signal resonant frequency; Z0 is the characteristic impedance, which is related to the electromagnetic wave propagation characteristics; Q is the quality factor, which is used to measure the energy loss of the system; L is the inductance, which is the inductance, which is related to the radius and number of turns of the spiral ring coil; B 1x is the component of the magnetic field intensity in the x-axis direction obtained by Biot-Savart; M xy is the transverse component of the magnetization vector in the xy plane, i represents the current, j represents the imaginary unit, ν represents the unit volume, and B max is the maximum magnetic field strength, B min is the minimum magnetic field strength, B mean is the average value of magnetic field strength.

[0064] Step 2: Engineers used electromagnetic simulation software CST to design the radius R and height H of the saddle coil 1, as well as the shape and path of the wire in the saddle coil 1 to achieve circular polarization.

[0065] The saddle coil is designed to achieve circular polarization, improving the uniformity and sensitivity of the imaging signal. The geometry of the saddle coil enables the coil to generate magnetic fields in both horizontal and vertical directions, forming a circularly polarized field distribution. This design effectively enhances signal reception capabilities, especially under low field strength conditions.

[0066] Main parameters:

[0067] The radius R and height H of the saddle coil 1 determine the coverage of the magnetic field.

[0068] Wire shape and routing: Ensure symmetric current distribution to achieve ideal polarization.

[0069] Known quantities: Basic design shape and size requirements of the coil.

[0070] Unknown quantities: Specific geometric parameters to achieve optimal circular polarization.

[0071] Step 3: The circuit engineer uses the circuit simulation software CST Design Studio to adjust the matching circuit 8 for optimal design so that the coil operates at the Larmor frequency and optimizes performance.

[0072] Adjust the matching circuit 8 of the dual-channel RF coil so that each coil can operate at the target Larmor frequency to ensure the best signal transmission and reception effect. By optimizing the parameters of the tuning capacitor and matching inductor, the precise resonance and impedance matching of the coil can be achieved to improve the signal strength and signal-to-noise ratio.

[0073] Main parameters:

[0074] Tuning capacitor Ct: used to fine-tune the resonant frequency of the coil to the Larmor frequency to ensure that the coil works efficiently at the target frequency.

[0075] Matching inductor Lm: Adjust the inductance value to achieve impedance matching, reduce signal reflection, and improve signal coupling efficiency.

[0076] Frequency adjustment range: The tuning capacitor and matching inductor in the matching circuit 8 are designed to accurately cover the required Larmor frequency (3.02 MHz at 70.9 mT).

[0077] Known Quantity: The design target frequency of the coil is the Larmor frequency.

[0078] Unknown quantities: Optimal matching circuit 8 parameter configuration, including the exact values ​​of tuning capacitors and matching inductors.

[0079] The geometric parameters of the solenoid are optimized based on a genetic algorithm and combined with a specific saddle-shaped structure to achieve the best magnetic field distribution and signal receiving efficiency, significantly improving the uniformity and sensitivity of imaging.

[0080] After the above steps, the design parameters of the solenoid coil 2 are: the first radius r is 0.12m, the coil spacing d is 0.01m and 0.005m, which can effectively improve the magnetic field uniformity of the coil; the total number of coil windings n is 27 turns, which helps to enhance the magnetic field strength. Specifically, the spiral ring coil windings include, from top to bottom, a spiral ring coil with a 3-turn pitch of 1cm, a spiral ring coil with a 2-turn pitch of 0.5cm, a spiral ring coil with 18 turns of 1cm, a spiral ring coil with a 2-turn pitch of 0.5cm, and a spiral ring coil with a 2-turn pitch of 1cm.

[0081] The dimensions of the saddle-shaped coil 1 are as follows: the second radius R is 0.13 m and the height H is 0.24 m. Such a structure can expand the coverage of the magnetic field to the greatest extent.

[0082] The capacitance parameters of the matching circuit 8 are set as follows: the upper capacitance element 12 of the solenoid coil is 100pF, which is used for tuning the solenoid coil 2; the first tuning network capacitance 27 is 220pF, and the second tuning network capacitance 29 is 150pF, which is used for signal balance-unbalance conversion, impedance matching and noise suppression to ensure efficient and stable signal transmission of the RF coil; the tuning capacitance of the tuning component 28 is 180pF, which is used for the tuning network of the saddle coil 1. Based on the above, through the coordinated optimization of the solenoid coil 2 and the saddle coil 1, it can operate at the same Larmor frequency of 3.02MHz, thereby improving the signal transmission efficiency and imaging quality.

[0083] Compared with the prior art, the dual-channel RF coil design method of the present application has the following significant advantages:

[0084] 1. Improve signal reception uniformity and sensitivity

[0085] 2. Optimize matching performance and achieve precise resonance by adjusting matching circuit 8

[0086] 3. Reduce noise and improve signal-to-noise ratio: The geometric optimization of the solenoid and the circular polarization design of the saddle coil work together to effectively suppress the interference of background noise. The solenoid geometric parameters optimized by genetic algorithm make the magnetic field more concentrated and stable, while the circular polarization design further homogenizes the signal reception, thereby significantly improving the signal-to-noise ratio.

[0087] 4. Enhanced imaging effect and adaptation to low field strength conditions: The above steps work together to improve the imaging capability of the system under low field strength. The circular polarization design and matching circuit 8 adjustment enable the dual-channel coil to effectively adapt to low field strength magnetic resonance imaging and provide clearer and higher resolution images than traditional single-channel coils.

[0088] Circular polarization effect: Through the saddle coil design, the magnetic field can act on the sample in multiple directions at the same time, enhancing the signal uniformity.

[0089] Matching circuit 8 optimization: Fine adjustment of matching circuit 8 ensures efficient transmission of energy and minimal reflection, reducing energy loss.

[0090] Improved signal-to-noise ratio: The optimized coil and circuit design make the received signal stronger and the noise lower, ultimately enhancing the accuracy and effect of imaging.

[0091] Based on the above, the performance of the dual-channel RF coil provided in the present application in ultra-low field magnetic resonance imaging applications is significantly improved, providing reliable technical support for the acquisition of high-quality images and opening up new avenues for the widespread application of magnetic resonance technology.

[0092] Description: Utilizes a conventional solenoid coil 2 and optimizes signal reception by reducing external noise interference through improved shielding materials and design.

[0093] Advantages and disadvantages: This solution has improved shielding effect and noise suppression, but the magnetic field uniformity and circular polarization effect of the solenoid are still not as good as those of the saddle coil, and the overall imaging effect is not ideal.

[0094] Compared with the existing technical solutions, the dual-channel RF coil design in this application combines the circular polarization advantages of the saddle coil and the optimized matching circuit 8 design, providing better signal uniformity, noise suppression and matching effects. Therefore, the solution of this application has unique advantages and wider applicability in ultra-low field magnetic resonance imaging applications.

[0095] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0096] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A dual-channel radio frequency coil, characterized in that: The dual-channel radio frequency coil includes a solenoid coil and a saddle coil located outside the solenoid coil; The solenoid coil comprises a spiral ring coil winding and a wire component; the spiral ring coil winding comprises a plurality of spiral ring coils connected in sequence; the wire component consists of an upper horizontal wire, a lower horizontal wire, a solenoid vertical wire, a spiral coil upper capacitor element and a spiral coil middle and lower excitation element; one end of the upper horizontal wire is connected to one end of the spiral coil upper capacitor element, and the other end of the upper horizontal wire is connected to the solenoid vertical wire; the other end of the spiral coil upper capacitor element is connected to the first spiral ring coil; the lower horizontal wire end is connected to one end of the spiral coil middle and lower excitation element, and the other end of the lower horizontal wire is connected to the solenoid vertical wire; the other end of the spiral coil middle and lower excitation element is connected to the last spiral ring coil; the spiral coil upper capacitor element is used to adjust the resonant frequency of the solenoid coil; The saddle coil comprises a first saddle coil group, a second saddle coil group and a matching circuit; the first saddle coil group and the second saddle coil group are arranged in a mirror image; The matching circuit includes a tuning component, a first coil component, a first tuning network capacitor, a first balun, a matching excitation element, a second balun, a second tuning network capacitor and a second coil component connected in sequence; the first coil component is connected to the first saddle coil group; the tuning component includes a tuning capacitor and a matching inductor; the tuning component, the first tuning network capacitor and the second tuning network capacitor are used to adjust the resonant frequency of the saddle coil.

2. The dual-channel radio frequency coil according to claim 1, characterized in that: The spiral ring coil winding includes a first spiral ring coil group, a second spiral ring coil group, a third spiral ring coil group, a fourth spiral ring coil group and a fifth spiral ring coil group; the first spiral ring coil group includes 3 turns of the first spiral ring coil; the second spiral ring coil group includes 2 turns of the second spiral ring coil; the third spiral ring coil group includes 18 turns of the third spiral ring coil; the fourth spiral ring coil group includes 2 turns of the fourth spiral ring coil; the fifth spiral ring coil group includes 2 turns of the fifth spiral ring coil.

3. The dual-channel radio frequency coil according to claim 2, characterized in that: The turn distances between the first spiral toroidal coils, the turn distances between the second spiral toroidal coils, the turn distances between the third spiral toroidal coils, the turn distances between the fourth spiral toroidal coils, and the turn distances between the fifth spiral toroidal coils are 1 cm or 0.5 cm.

4. The dual-channel radio frequency coil according to claim 2, characterized in that: The first radii of the first spiral toroidal coil, the second spiral toroidal coil, the third spiral toroidal coil, the fourth spiral toroidal coil, and the fifth spiral toroidal coil are equal.

5. The dual-channel radio frequency coil according to claim 1, characterized in that: The first radius is 0.12 m.

6. The dual-channel radio frequency coil according to claim 1, characterized in that: The first saddle coil group comprises an upper left semicircular coil, a lower left semicircular coil, a left front vertical wire and a left rear vertical wire; two endpoints of the upper left semicircular coil are respectively connected to one end of the left front vertical wire and one end of the left rear vertical wire; two endpoints of the lower left semicircular coil are respectively connected to the other end of the left front vertical wire and the other end of the left rear vertical wire; The second saddle coil group comprises an upper right semicircular coil, a lower right semicircular coil, a right front vertical wire and a right rear vertical wire; two endpoints of the upper right semicircular coil are respectively connected to one end of the right front vertical wire and one end of the right rear vertical wire; two endpoints of the lower right semicircular coil are respectively connected to the other end of the right front vertical wire and the other end of the right rear vertical wire; The upper left semicircular coil and the lower left semicircular coil are arranged in parallel with the upper right semicircular coil and the lower right semicircular coil.

7. The dual-channel radio frequency coil according to claim 6, characterized in that: The second radii of the first circular ring and the second circular ring are equal; the first circular ring is composed of an upper left semicircular ring coil and a lower left semicircular ring coil; the second circular ring is composed of an upper right semicircular ring coil and a lower right semicircular ring coil.

8. The dual-channel radio frequency coil according to claim 7, characterized in that: The second radius is 0.13 m.

9. The dual-channel radio frequency coil according to claim 1, characterized in that: The height of the saddle coil is 0.24 m.

10. A design method for a dual-channel radio frequency coil, characterized in that: The design method of the dual-channel radio frequency coil includes: The genetic algorithm is used to optimize the geometric parameters of the solenoid to obtain the optimal geometric parameters of the solenoid; the geometric parameters of the solenoid include the radius of the spiral ring coil, the turn distance between the spiral ring coils and the number of windings of the spiral ring coil winding; the number of windings of the spiral ring coil winding is the number of the spiral ring coils; The dual-channel radio frequency coil of claim 1 is prepared based on the optimal solenoid geometric parameters.

Images