Off-line test system for magnetic resonance image enhanced metamaterial

Abstract

The invention relates to the technical field of magnetic resonance, and discloses a magnetic resonance image enhancement metamaterial off-line test system, a constant current source circuit is used for providing current for each channel coil, and a main control chip controls the constant current source circuit through a relay to carry out detuning control on each channel coil; the main control chip controls the tuning voltage circuit through the relay and performs tuning control on each channel coil; the control chip is used for controlling the ADC module in the control chip and acquiring a voltage value and a current value of the channel coil; the control chip is used for controlling the radio frequency switching circuit and selecting radio frequency receiving of the channel coil. Tuning and detuning can be selectively carried out on coil channels through the constant current source circuit module and the tuning voltage circuit module, radio frequency selective receiving is carried out on the channels through the radio frequency receiving channel switching circuit module, voltage and current values collected by the system for all the channels of the coil are uploaded to an upper computer, and the upper computer displays the values.

Description

Technical Field

[0001] The present invention relates to the field of magnetic resonance technology, and particularly to an off-line test system for magnetic resonance image enhancement metamaterials. Background Art

[0002] The application of metamaterials in nuclear magnetic resonance, especially in improving imaging quality and reducing equipment costs, has great potential. However, currently, when using metamaterials for MRI, there is a lack of standardized testing and evaluation methods, leading to a series of problems. The following are the main problems related to the lack of testing and evaluation methods and their impacts:

[0003] First, there is a lack of unified testing standards. Currently, the performance evaluation of metamaterials in magnetic resonance imaging usually relies on self-developed methods of individual research teams or companies. Due to the lack of unified industry standards, the following problems occur: Difficulty in comparing test results: Different research teams may use different test protocols, equipment, and parameters, making it difficult to directly compare the test results of the same material in different laboratories, which is not conducive to peer evaluation and technological progress. Difficulty in establishing benchmarks: Without unified standards, it is difficult to establish clear performance benchmarks, especially in terms of frequency response, magnetic field enhancement effect, imaging gain, etc. This limits the evaluation of new materials and the promotion of market applications.

[0004] Second, the complexity of performance evaluation. The performance of metamaterials in magnetic resonance imaging is affected by multiple parameters, including material structure, frequency response, dielectric properties, permeability, etc. Traditional imaging performance evaluation methods may be difficult to comprehensively reflect these complex factors: Difficulty in optimization under multiple parameter influences: When evaluating the enhancement effect of metamaterials on MRI systems, there are many influencing factors, including the electromagnetic properties of the material itself, the tuning accuracy of the resonance frequency, and the uniformity of the field strength distribution. This complexity makes it difficult for a single test method to fully capture all the key performance indicators of the material. The influence of dynamic and static magnetic fields: Since the design of metamaterials usually involves complex structures that interact with magnetic fields, their performance may be different under dynamic and static magnetic fields. Existing test methods are difficult to accurately evaluate the performance of materials under different magnetic field conditions.

[0005] Third, it is difficult to evaluate quantitatively. For the enhancement effect of metamaterials in magnetic resonance imaging, the quantitative evaluation method is not yet mature. Currently, most evaluation methods still rely on qualitative analysis or local parameter evaluation, lacking comprehensive quantitative indicators. For example: Quantification of the improvement in imaging signal-to-noise ratio (SNR): Although metamaterials can improve the SNR of MRI, there are certain difficulties in the specific quantitative evaluation of this improvement at present. Especially in clinical applications, the improvement of SNR is interfered by various factors, and it is difficult to isolate the contribution of metamaterials alone. Measurement of the resonance frequency tuning accuracy: In magnetic resonance imaging, the resonance frequency tuning of metamaterials is crucial, especially for enhancing the imaging signal of specific frequencies. However, existing methods are difficult to accurately quantify the accuracy of this tuning, which affects the optimal design of materials. Summary of the Invention

[0006] Based on this, in view of the technical problem of the poor test effect of existing metamaterials, it is necessary to propose an off-line test system for magnetic resonance image-enhancing metamaterials.

[0007] In a first aspect, an off-line test system for magnetic resonance image-enhancing metamaterials is provided. The system includes: a control chip, a constant current source circuit, a tuning voltage circuit, and a radio frequency switching circuit. The control chip is respectively connected to one end of the constant current source circuit, one end of the tuning voltage circuit, and the radio frequency switching circuit. The other end of the constant current source circuit is connected to each channel coil. The other end of the tuning voltage circuit is connected to the channel coil. The channel coil is connected to the metamaterial.

[0008] The constant current source circuit is used to provide current for each channel coil, and the main control chip controls the constant current source circuit to perform detuning control on each channel coil through a relay.

[0009] The main control chip controls the tuning voltage circuit through a relay to perform tuning control on each channel coil.

[0010] The control chip is used to control the ADC module inside the control chip to collect the voltage value and current value of the channel coil.

[0011] The control chip is used to control the radio frequency switching circuit to select the radio frequency reception of the channel coil.

[0012] The off-line test system for magnetic resonance image enhancement metamaterials proposed by the present invention, the system includes: a control chip, a constant current source circuit, a tuning voltage circuit, a radio frequency switching circuit, the control chip is respectively connected to one end of the constant current source circuit, one end of the tuning voltage circuit, the radio frequency switching circuit, the other end of the constant current source circuit is connected to each channel coil, the other end of the tuning voltage circuit is connected to the channel coil, and the channel coil is connected to the metamaterial; the constant current source circuit is used to provide current for each channel coil, and the main control chip controls the constant current source circuit to perform detuning control on each channel coil through a relay; the main control chip controls the tuning voltage circuit through a relay to perform tuning control on each channel coil; the control chip is used to control the ADC module inside the control chip to collect the voltage value and current value of the channel coil; the control chip is used to control the radio frequency switching circuit to select the radio frequency reception of the channel coil. The present invention can perform tuning and detuning on the selectivity of the coil channels through the constant current source circuit module and the tuning voltage circuit module, and perform selective radio frequency reception on the channels through the radio frequency reception channel switching circuit module. The voltage and current values collected by the system for each coil channel are uploaded to the upper computer, and the upper computer displays these values. In addition, key parameters such as resonance frequency, quality factor, coupling degree, and matching can be determined through devices such as a network analyzer. Description of the Drawings

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0014] Among them:

[0015] Figure 1 It is a schematic structural diagram of an off-line test system for magnetic resonance image enhancement metamaterials in an embodiment;

[0016] Figure 2 It is the mechanical appearance design of an off-line test system for magnetic resonance image enhancement metamaterials in an embodiment;

[0017] Figure 3 It is a design diagram of a double-P coil test probe of a data processing device in an embodiment;

[0018] Figure 4 It is the hardware functional architecture of a computer device in an embodiment. Detailed Embodiments

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification and claims of this application or the above drawings are used to distinguish different objects and not to describe a specific order.

[0020] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0022] Please refer to Figure 1 as shown Figure 1 which is a schematic structural diagram of an off-line test system for a magnetic resonance image enhancement metamaterial provided by an embodiment of the present invention. The off-line test system for a magnetic resonance image enhancement metamaterial includes: a control chip, a constant current source circuit, a tuning voltage circuit, and a radio frequency switching circuit. The control chip is respectively connected to one end of the constant current source circuit, one end of the tuning voltage circuit, and the radio frequency switching circuit. The other end of the constant current source circuit is connected to each channel coil. The other end of the tuning voltage circuit is connected to the channel coil, and the channel coil is connected to the metamaterial;

[0023] The constant current source circuit is used to provide current for each channel coil, and the main control chip controls the constant current source circuit to perform detuning control on each channel coil through a relay; The main control chip controls the tuning voltage circuit through a relay to perform tuning control on each channel coil;

[0024] The control chip is used to control the ADC module inside the control chip to collect the voltage value and current value of the channel coil;

[0025]

[0026] The control chip is used to control the RF switching circuit and select the RF reception of the channel coil.

[0027] Reference Figure 2 , which is the mechanical appearance design of the off-line test system for magnetic resonance image enhancement metamaterials.

[0028] Among them, as an example, the test platform uses STMicroelectronics STM32F47ZGT6 as the control chip. This control chip is used to run embedded software, control the tuning and detuning of the 24-channel coil, collect the voltage value, current value of the 24-channel coil, the total current value of the entire platform, and the temperature value through its own ADC module function. The RF channel of the platform can be switched through the IO port. Its serial communication can perform human-computer interaction communication with the PC-side host computer.

[0029] As an example, for the constant current source circuit, to ensure that each channel of the platform has a stable 150 mA current when the tuning diode is turned on, the constant current source circuit uses ADI's LT 3092. This chip is a multi-functional IC that can be used as a two-terminal programmable current source, and only two external resistors are added to set the output current between 0.5 mA and 200 mA. It can provide a stable 150 mA current for each channel coil. No external bypass capacitor is required to maintain stability. The main control chip can control the detuning of the diodes of each channel coil through a relay.

[0030] As an example, for the tuning voltage circuit, the tuning voltage circuit uses the MC34063 DC-DC power chip. This chip contains a temperature-compensated reference voltage source, a comparator, an oscillator that can effectively limit the current and control the duty cycle, a driver, and a high-current output switch, etc. With a small number of external components, it can form a boost, buck, and voltage-inverting DC-DC converter. This module is designed to output a voltage of -30V. The main control chip can control the tuning voltage circuit through a relay to tune the diodes of each channel coil.

[0031] As an example, the RF switching circuit uses Qorvo's QPC6064. This chip is a silicon-on-insulator (SOI) single-pole six-throw (SP6T) switch, designed for cellular, 3G, LTE, and other high-performance communication systems. It provides a high-isolation symmetric topology with excellent linearity and power handling capabilities. No blocking capacitor is required on the RF port. This design is non-reflective, so the RFX port is terminated with 50 ohms in the off state. QPC6064 is compatible with +1.8V logic and uses a single pin to disable the internal negative voltage generator (NVG) and provide negative voltage from outside the chip when necessary. This module is used to switch and select the RF reception of each channel.

[0032] In one embodiment, the off-line test system for magnetic resonance image enhancement metamaterials further includes a temperature detection circuit. The control chip is connected to the temperature detection circuit, and the temperature detection circuit is used to monitor the system temperature. As an example, the temperature detection circuit uses the LM75A, which is a temperature-to-digital converter that employs an on-chip bandgap temperature sensor and AD conversion technology. This device is also a thermal detector that provides an over-temperature detection output. The LM75A includes multiple data registers: the configuration register (Conf) is used to store device settings. The device also includes an open-drain output (OS) that is activated when the temperature exceeds the programmed limit. This module is used to monitor the platform temperature and protect the entire system function.

[0033] In one embodiment, the off-line test system for magnetic resonance image enhancement metamaterials further includes a host computer. The host computer is used to receive the voltage value and current value of the channel coil transmitted by the control chip. As an example, the host computer is a PC. The test platform and the PC use the RS232 communication method, and its communication IC uses the YouTai semiconductor SP3232EEN. This IC has two receivers and two drivers, as well as a dual charge pump circuit. This device meets the TIA / EIA-232-F requirements and provides an electrical interface between the asynchronous communication controller and the serial port connector. The data signal rate of this device is up to 250 Kbit / s, and the driver output rate is up to 35 V / μs. This module mainly cooperates with the host computer of the PC for human-computer interaction operations.

[0034] In one embodiment, the off-line test system for magnetic resonance image enhancement metamaterials further includes a current detection circuit. The control chip is connected to the current detection circuit, and the current detection circuit is used to collect the current values of the diodes of each channel coil and monitor the current flowing through the diodes. As an example, the current detection circuit uses the ADI (Analog Devices) LTC6101 current sensing amplifier. This chip is a multi-functional, high-voltage, high-side current detection amplifier. The LTC6101 operates on a power supply of 4V to 60V. The LTC6101 monitors the current through the voltage of an external sense resistor. The internal circuit converts the input voltage into an output current, allowing a small detection signal on a high common-mode voltage to be converted into a ground-referenced signal. The low DC bias allows the use of a small shunt resistor and a large gain setting resistor. Therefore, the power loss of the shunt is reduced. This module is used to collect the current values of the diodes of each channel coil and monitor the current flowing through the diodes.

[0035] As an example, for the method of using the platform, the host computer on the PC side performs interface operations and displays. It communicates and controls with the main control chip of the platform system through its serial port RS232. The platform is connected to external multi-channel coils. Through the host computer on the PC side, the coil channels can be tuned and detuned selectively through the constant current source circuit module and the tuning voltage circuit module, and 24-channel radio frequency selective reception can be performed through the radio frequency receiving channel switching circuit module. The platform system uploads the voltage and current values collected from each coil channel to the PC side through serial communication, and the host computer displays these values. The host computer on the PC side can also display the platform temperature value and the total system current value.

[0036] In one embodiment, the off-line test system for magnetic resonance image enhancement metamaterials adopts a dual-P coil test probe design. Refer to Figure 3 , the dual-P coil test probe adopts the overlapping coil method. The overlapping coil method is mainly a decoupling method, especially applied in fields such as nuclear magnetic resonance and wireless power transmission, and is used to reduce or eliminate the coupling effect between adjacent coils.

[0037] Basic principle: By overlapping the areas between adjacent coils to reduce the mutual magnetic flux between the coils. Reduce the mutual inductance between the coils, so as to achieve the purpose of decoupling between adjacent coils.

[0038] Calculation of mutual inductance: Mutual inductance can be calculated through vector potential, and the formula is as follows:

[0039] M12 = ∮A12dr2, where M12 is the mutual inductance between the coils, A12 is the vector potential induced in coil 2 by the current in coil 1, and R2 is the distance between the two coils.

[0040] Application method: Coil overlapping setting: Lift the right coil upward by a certain distance (such as 3 mm) and place it overlapping with the left coil in a staggered manner. Change the overlapping area: Change the size of the overlapping area between the two coils by changing the distance r between the two coils. Observe the coupling change: Observe the coupling change of the dual-coil system during the process of changing the overlapping area.

[0041] Relationship between mutual inductance and position change: When the coils move from complete coincidence to partial coincidence (the overlapping part is within 0.05 m), the mutual inductance between the coils is positive and the mutual inductance keeps decreasing. When the coils move from 0.05 m of coincidence to the position where the two coils are side by side, the mutual inductance between the coils is negative and the absolute value of the mutual inductance increases. When the coils move from the side-by-side position to the position where the two coils are infinitely far apart, the mutual inductance between the coils is negative and its absolute value keeps decreasing, and finally the mutual inductance value approaches 0.

[0042] Advantages of the overlapping coil method: At a specific overlapping distance (e.g., when $r = 19$ mm), the S11 parameter can reach the minimum value (e.g., -23.1 dB). At this time, the resonant peaks merge from double peaks into a single peak, effectively removing the coupling between the coils. The overlapping coil method can make the mutual inductance between the two receiving coils zero, that is, the mutual inductance electromotive force of the receiving coils is also zero, and there is no signal coupling between the two coils. In magnetic resonance imaging (MRI), it can improve the imaging quality and reduce artifacts. The overlapping coil method is an effective decoupling method. By adjusting the overlapping area and position of the coils, the coupling effect between adjacent coils can be effectively reduced or eliminated, thereby improving the system performance and efficiency.

[0043] The system platform of the present invention can conveniently test the effects of metamaterials on key parameters such as resonant frequency, quality factor, coupling degree, and matching.

[0044] 1. When testing the resonant frequency: For microwave frequencies, a network analyzer can be used to measure the S parameters (S11, S21, etc.). By analyzing the changes of these parameters at different frequencies, the resonant frequency can be found.

[0045] 2. Testing the quality factor of metamaterials is an important step in evaluating their resonant performance, especially in fields such as filters and sensors that have high requirements for resonant characteristics. The quality factor refers to the energy loss situation of the material near the resonant frequency, and the calculation formula is:

[0046]

[0047] where $f_0$ is the resonant frequency and $\Delta f$ is the bandwidth (frequency width) of the resonant peak, that is, the width at the point where the power of the peak is reduced by half (-3 dB). Using a network analyzer can not only measure the S parameters but also automatically calculate the quality factor. By performing a fine frequency scan to determine the half-power point of the resonant peak, that is, the bandwidth at the -3 dB point, and then using the above formula to calculate.

[0048] 3. Testing the coupling degree of metamaterials is an important aspect for understanding their resonant performance and energy transmission characteristics, especially when designing devices such as filters, waveguides, and sensors. The coupling degree represents the energy transfer efficiency between two resonant structures and affects the splitting degree and bandwidth width of the resonant frequency. By measuring the transmission (S21) and reflection (S11) coefficients of the metamaterial system, relevant information about the coupling strength can be obtained. The specific steps are as follows:

[0049] 3.1 Set the frequency scan range: Near the estimated resonant frequency of the coupling structure, use a network analyzer to perform a detailed frequency scan on the transmission and reflection parameters.

[0050] 3.2 Analysis of Resonant Frequency Splitting: When the coupling between two structures is strong, their resonant frequencies will split. By analyzing the split frequency interval in the transmission spectrum, the degree of coupling can be indirectly estimated.

[0051] 3.3 Determine the bandwidth: By observing the bandwidth width of the transmission peak or reflection valley, the strength of the coupling can be further judged. The higher the coupling degree, the wider the bandwidth is generally.

[0052] 4. Testing the matching degree of metamaterials is crucial for optimizing their performance in different applications. The goal of matching testing is to determine the degree of compatibility between metamaterials and specific electromagnetic waves (such as microwaves, radio frequency, or light waves) at different frequencies. Good matching can reduce reflection losses and improve energy transmission efficiency, so it is particularly critical in applications such as filters, antennas, and stealth materials. The following are the main methods for testing the matching of metamaterials:

[0053] 4.1 Return loss measurement (S11 parameter)

[0054] Reflection loss (or S11 parameter) is an important indicator for evaluating matching performance. By measuring the amount of reflection of the incident wave on the material surface, the degree of material matching can be determined.

[0055] Network analyzer: A network analyzer can measure the reflection coefficient (S11) and plot the S11 curve by sweeping the frequency. At frequencies with good matching, the S11 value typically has a significant dip (e.g., below -10dB), indicating low reflection loss and good matching.

[0056] VSWR: The degree of matching can be further quantified by measuring the Voltage Standing Wave Ratio (VSWR). An ideal match has a VSWR close to 1:1.

[0057] 4.2 Absorption rate measurement

[0058] For absorbing materials or stealth materials, absorptivity is also an important indicator to measure the degree of matching. Transmission and reflection coefficient: By measuring the transmission coefficient (S21) and reflection coefficient (S11) respectively, the absorptivity can be calculated:

[0059] A=1-|S11| 2 -|S21| 2

[0060] An absorptivity close to 1 indicates that the materials are well matched and most of the energy is absorbed.

[0061] 4.3 Impedance Measurement

[0062] In some applications, especially at microwave frequencies, the matching performance can be evaluated by measuring the equivalent impedance of the material.

[0063] Impedance Analyzer: Use an impedance analyzer to measure the complex impedance (real and imaginary parts of the impedance) of a material, and then compare it with the free space impedance (usually 377 ohms). Materials with a high degree of matching should have an impedance close to the free space impedance.

[0064] Standing Wave Mode: When testing a sample in a waveguide, the change in the standing wave mode can be analyzed to determine the degree of matching. The fewer the standing wave modes, the better the matching.

[0065] In an achievable way, in this platform, its hardware functional architecture (as Figure 4 shown) mainly consists of a power supply module, a control chip module, a radio frequency channel control module, a tuning-detuning low-noise amplifier power supply module, etc. Among them, the control chip module is used to connect to the upper control host and provide control for the entire system; the radio frequency channel control module is used for switching the debugging switches of the radio frequency coil channels. Each coil socket contains 12 radio frequency channels, and the entire system has a total of 24 radio frequency coil channels. Its working process is that the RF signal from the signal source is transmitted to the coil under test through the radio frequency front end. When the coil is not matched to 50 ohms, a reflected signal will always be generated. Therefore, the matching status of the coil can be seen in real time. When the corresponding tuning voltage changes, the matching status of the coil changes simultaneously, and the reflected signal also changes simultaneously. When the reflected signal reaches the required smaller value, it can be considered that the coil has been tuned and matched.

[0066] The power supply module in it adopts an independent unit DC-DC, LDO current mode design. At the load end, an FPGA is used to control the PMOS transistor to control the on and off of the power supply, and then to tune and detune the coil. The type of coil, whether it is an orthogonal coil or a single-polarized coil, can be judged by detecting the TTL level. An overcurrent protection is designed at the load end. By collecting the voltage of the sampling resistor and feeding it back to the current sampling chip, when the voltage exceeds the set threshold, the power supply output will be automatically turned off to protect the circuit. Temperature sensors are placed at key parts of the board to protect the control board from overheating. The radio frequency switch controls the RF relay through the FPGA to turn the radio frequency source on and off. By collecting the voltage and current of each channel, the data is transmitted to the PC side through RS485, and the data is displayed on the PC side. The PC side can also perform human-machine operation control on the radio frequency switch and the channel control board.

[0067] To meet the high-channel radio frequency coil debugging requirements, this test box adopts a layout method of stacking multiple modules. 4 test box modules can be used, supporting ≥48-channel testing. In cooperation with a vector network analyzer, a dedicated test probe, and dedicated test control software (such as Figure 3As shown, the test platform has a dedicated test probe (isolation ≤ -45 dB) that can achieve multi-parameter testing of multi-channel RF coils, and is used to evaluate the effects of metamaterials on parameters such as the resonant frequency, coil matching, channel coupling, and quality factor of RF coils. The software has the following functions: ① Module selection, supporting a maximum expansion of 4 groups of coil test box modules, which can correspondingly support ≥ 48 receiving channels; ② Power supply control and status display of the test box, including tuning / detuning voltage and current, amplifier power supply voltage, and internal 12V power supply status; ③ Tuning / detuning control of RF channels; ④ Coil identification code display; ⑤ Realize automatic control and switching of coil channels.

[0068] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the above-mentioned division of each functional unit and module is used as an example. In actual applications, the above functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above.

[0069] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. An off-line test system for a magnetic resonance image enhancement metamaterial, characterized in that, The off-line test system for magnetic resonance image enhancement metamaterials includes: a control chip, a constant current source circuit, a tuning voltage circuit, and a radio frequency switching circuit. The control chip is respectively connected to one end of the constant current source circuit, one end of the tuning voltage circuit, and the radio frequency switching circuit. The other end of the constant current source circuit is connected to each channel coil. The other end of the tuning voltage circuit is connected to the channel coil. The channel coil is connected to the metamaterial; The constant current source circuit is used to provide current for each channel coil. The main control chip controls the constant current source circuit to perform detuning control on each channel coil through a relay; The main control chip controls the tuning voltage circuit through a relay to perform tuning control on each channel coil; The control chip is used to control the ADC module inside the control chip to collect the voltage value and current value of the channel coil; The control chip is used to control the radio frequency switching circuit to select the radio frequency reception of the channel coil.

2. The off-line test system for magnetic resonance image enhancement metamaterials according to claim 1, wherein The off-line test system for magnetic resonance image enhancement metamaterials further includes: a temperature detection circuit. The control chip is connected to the temperature detection circuit. The temperature detection circuit is used to monitor the system temperature.

3. The off-line test system for magnetic resonance image enhancing metamaterials according to claim 1, wherein The off-line test system for magnetic resonance image enhancement metamaterials further includes: a host computer. The host computer is used to receive the voltage value and current value of the channel coil transmitted by the control chip.

4. The off-line test system for magnetic resonance image-enhanced metamaterials according to claim 1, wherein The off-line test system for magnetic resonance image enhancement metamaterials further includes: a current detection circuit. The control chip is connected to the current detection circuit. The current detection circuit is used to collect the current value of the diode of each channel coil and monitor the current flowing through the diode.

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