Wireless resonant ring, magnetic resonance carotid artery array coil, and imaging method

Abstract

The present invention relates to a magnetic resonance imaging technique for the carotid artery, and in particular to a wireless resonant ring, a magnetic resonance carotid artery array coil comprising the wireless resonant ring, and an imaging method. The wireless resonant ring uses a loop structure, can not only be used in conjunction with various commercial magnetic resonance carotid artery coils, but also combined with a carotid artery array coil to form a magnetic resonance carotid artery array coil having better imaging performance. Such a wireless resonant ring can enhance the distribution of B1- field near the wireless resonant ring, and hardly changes the distribution of B1+ field of the surrounding coil, thereby effectively improving the signal-to-noise ratio of imaging. In addition, compared with use of a carotid artery coil, addition of the wireless resonant ring is more conducive to imaging at a deeper subcutaneous position, thereby acquiring an image having higher resolution, higher signal-to-noise ratio and higher quality at the carotid artery position.

Description

A wireless resonant ring, magnetic resonance carotid artery array coil and imaging method Technical Field

[0001] The present invention relates to the field of magnetic resonance imaging technology, and is particularly suitable for performing magnetic resonance imaging on specific areas such as the carotid artery. In particular, the present invention relates to a specially designed wireless resonant ring, a magnetic resonance array coil having the wireless resonant ring, and a corresponding magnetic resonance carotid artery imaging method. Background Art

[0002] In China, approximately 2.5 million new stroke cases occur each year, and approximately 1.5 million people die from stroke each year, making it the leading cause of death among all major diseases. Among stroke diseases, carotid atherosclerosis accounts for the highest proportion.

[0003] In recent years, carotid magnetic resonance angiography (MRA) has been increasingly used in the clinical diagnosis of stroke. This is because the technology takes advantage of the high blood flow in the neck vessels and the lack of interference from motion artifacts such as breathing, thereby being able to obtain high-quality images and angiography from the origin to the siphon of the carotid artery. At the same time, the image can be rotated in three dimensions for multi-angle observation to eliminate the influence of overlapping blood vessels and make the lesions appear more clearly. With the development of technology, MRA can also use special pre-saturation methods to remove the influence of the carotid artery and only display the jugular vein. This can also understand the situation of tumor invasion and compression of the vein, further expanding the application scenarios of this technology.

[0004] In magnetic resonance imaging (MRI), due to hemodynamic reasons, the primary observation area is concentrated within 10 mm above and below the carotid bifurcation. This is typically at the level of the common carotid artery bifurcation at the C3-C5 vertebrae, or between the hyoid bone and the upper edge of the thyroid cartilage, generally located 2-4 cm subcutaneously. Imaging techniques for this area, particularly those for imaging the carotid artery and its vessel wall, are highly dependent on the image signal-to-noise ratio (SNR). From a hardware perspective, achieving a sufficient SNR places extremely high demands on the structural design and engineering implementation of the receiving coil.

[0005] There are two main types of neck coils currently used in the market. One type of neck coil is a strip-shaped coil that can be wrapped around the neck. Although this type of coil can improve the uniformity of overall imaging, it is not optimized for imaging in the area near the carotid bifurcation. This will result in insufficient image resolution and cannot be effectively used for medical imaging diagnosis. The other type is a two-sided separated array coil, which can be placed in line with the carotid artery and is specifically used for carotid artery imaging. However, the structural units that make up the array coil are small, so the signal-to-noise ratio is higher on the surface. As the imaging depth increases, the signal-to-noise ratio will gradually decrease, which makes the signal-to-noise ratio for the subcutaneous area of ​​interest significantly insufficient. In particular, it is difficult to provide a better imaging signal-to-noise ratio for some people whose carotid arteries are located deep below the skin.

[0006] Although existing technologies can further optimize the matching relationship between the central area of ​​coil imaging and the carotid bifurcation area of ​​clinical concern, and find more compatible solutions between TOF time-of-flight technology vascular imaging mode and PC phase contrast technology vascular imaging mode to utilize the respective advantages of different imaging modes, there is still an urgent need to significantly improve the imaging signal-to-noise ratio near the carotid artery, especially the imaging signal-to-noise ratio of specific areas at a certain depth under the skin.

[0007] Summary of the Invention

[0008] In response to the problems existing in the above-mentioned prior art, the present invention proposes a wireless resonant ring that can be used in conjunction with a general magnetic resonance carotid coil. This wireless resonant ring uses a loop structure, and provides a magnetic resonance carotid array coil with this wireless resonant ring, so as to image the deep-level positions of the carotid artery, especially the carotid bifurcation point and the common carotid artery position, increase the size of the coil unit structure unit, and improve the imaging depth. Without affecting the original carotid coil structure function, it can optimize the imaging of the signal-to-noise ratio at the subcutaneous carotid bifurcation, thereby improving the image quality, meeting the high-resolution imaging of the carotid artery and facilitating disease diagnosis.

[0009] Specifically, the present invention provides the following technical solutions:

[0010] In a first aspect, the present invention provides a wireless resonant ring for a carotid magnetic resonance imaging system. The resonant ring can be used with various commercially available carotid magnetic resonance coils and includes at least one conductive loop forming a closed loop structure, a resonant circuit consisting of at least one capacitor and at least one inductor, and at least two diodes to form a detuning mechanism. The conductive loop, resonant circuit, and diodes are optimized to resonate at a specific radio frequency, thereby enhancing signal reception at frequencies compatible with the magnetic resonance system.

[0011] Preferably, the wireless resonant ring further includes an adjustment capacitor connected to the conductive loop for adjusting the impedance of the resonant circuit to accommodate different MRI system parameters. The wireless resonant ring may further include one or more additional electronic components to fine-tune and match the resonant circuit, thereby achieving selective enhancement of specific frequency signals.

[0012] Preferably, the conductive loop of the wireless resonant ring is rectangular or square in shape to optimize signal capture in specific anatomical regions, such as the carotid bifurcation. Furthermore, to adapt to the skin surface of specific anatomical regions, the conductive loop can be constructed of a flexible material, thereby facilitating conformance to the surface of different patient anatomies.

[0013] Preferably, the type of the diode is selected from a PIN diode, a Schottky diode or any diode suitable for fast switching and detuned operation, thereby ensuring high imaging quality.

[0014] A second aspect of the present invention provides a carotid magnetic resonance array coil with a wireless resonant ring, comprising a carotid array coil and the aforementioned wireless resonant ring. The carotid array coil has a loop structure. With the wireless resonant ring, this carotid magnetic resonance array coil can achieve a higher signal-to-noise ratio and is more conducive to imaging areas at a certain depth below the skin.

[0015] Preferably, the carotid artery array coil is a multi-channel array coil, comprising at least one capacitor, at least one inductor, and at least two diodes that form a resonant and detuned mechanism. The coil switches between resonant and detuned modes to improve imaging quality. Furthermore, the multiple channels are configured in an overlapping and decoupled manner to reduce mutual interference between the channels.

[0016] Preferably, it further comprises a resonance module cooperating with the carotid artery array coil and the wireless resonant ring, the main function of which is to tune and match multiple channels to the required Larmor frequency.

[0017] Preferably, the device further comprises a trap circuit connected via the cable, for example, by forming an LC loop that resonates at a specific frequency of the unwanted signal to generate high impedance at the frequency, thereby suppressing the common mode current in the loop.

[0018] Preferably, the signal passes through the phase shifter after passing through the trap circuit. In order to reduce the insertion loss after the module is cascaded, the phase shifter can adopt a π-type phase shifter or a T-type phase shifter. In this way, the phase of the signal received from the coil is changed to the phase set by the magnetic resonance system through the phase shifter.

[0019] A third aspect of the present invention provides a method for magnetic resonance carotid array imaging using a wireless resonant ring, specifically comprising the following steps: S1. Positioning the wireless resonant ring in the patient's neck region; locating the wireless resonant ring and the carotid array coil; S2. Adjusting the wireless resonant ring to resonate at the Larmor frequency set by the magnetic resonance imaging system; S3. Performing a magnetic resonance imaging scan to capture the signal enhanced by the resonant ring; and processing the captured signal to generate an image of the carotid artery region. By adding the wireless resonant ring to the conventional carotid array coil, the method improves the signal-to-noise ratio and is more suitable for imaging deep locations.

[0020] Compared with existing technologies, the present invention offers the following advantages: First, for locations requiring specialized imaging of the carotid artery and its vessel wall, the carotid coil size is optimized, increasing the coil side length to ensure imaging depth of the common carotid artery. Second, a wireless resonant ring is added to enhance the signal-to-noise ratio near the subcutaneous region, with a significant improvement in the signal-to-noise ratio at the carotid bifurcation. The wireless resonant ring is also very convenient to use, being directly attached to the carotid coil and compatible with commercial carotid magnetic resonance coils. Imaging using a carotid magnetic resonance array coil with a wireless resonant ring can improve the signal-to-noise ratio of the neck vessels and vessel walls. In an embodiment, the signal-to-noise ratio of surface signals within 2 cm of the subcutaneous layer is more than doubled, and at the desired carotid artery imaging location, the signal-to-noise ratio is increased by approximately 50%. This improvement in the signal-to-noise ratio and image quality enhances the imaging of the vessels and their walls, facilitating subsequent diagnosis by physicians. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG1 is a circuit diagram of a unilateral carotid artery four-channel coil in one embodiment;

[0022] FIG2 is a schematic diagram of a single-channel coil radio frequency module in one embodiment;

[0023] FIG3 is a structural diagram of a magnetic resonance carotid artery array coil with a wireless resonant ring in one embodiment;

[0024] FIG4 is a schematic diagram of a wireless resonant ring in an embodiment;

[0025] FIG5 is a circuit diagram of a single-sided wireless resonant ring in an embodiment;

[0026] FIG6 is a schematic diagram of the B1+ field when a wireless resonant ring is used or not and when wireless resonant rings of different sizes are used;

[0027] FIG7 is a schematic diagram of received signals when a wireless resonant ring is used and when wireless resonant rings of different sizes are used;

[0028] FIG8 is a comparison of signal reception and signal-to-noise ratio curves when using only the carotid coil and when using it in conjunction with a 5 cm wireless resonant ring.

[0029] FIG9 is a structural distribution diagram of a magnetic resonance carotid artery array coil having a wireless resonant ring on one side in an embodiment. DETAILED DESCRIPTION

[0030] The technical solution of this patent will be further described in detail below in conjunction with specific embodiments. It should be noted that the following detailed description is exemplary and is intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this application belongs.

[0031] Carotid magnetic resonance angiography (MRA) requires the use of specially designed radiofrequency coils to obtain high-resolution vascular images. These coils must accurately capture signals in the carotid artery region and adapt to the complex human anatomy. This embodiment uses a two-sided, separate array coil as an example. However, it should be understood that based on the operating principles of this embodiment, those skilled in the art will readily extrapolate the concepts of this invention to various types of MRA array coils.

[0032] In the bilaterally separated array coil, the structure of an exemplary unilateral carotid coil is shown in Figure 1. The coil in the figure adopts a four-channel coil structure. The single-channel coil adopts a loop structure with four independent conductive paths, each corresponding to a channel, which are configured to capture signals from the neck area. The multiple pads in the figure are used to connect signal processing components to adjust and optimize the signals. The central connection area can integrate the signals of each channel and transmit them to the main processing unit of the MRA system through the circuit structure. The typical circuit structure includes a detuning circuit, a trap circuit, a tuning circuit, a preamplifier motherboard, and a preamplifier. Among them, the detuning circuit can temporarily detune the coil from the main magnetic field of the MRA system, thereby avoiding damage to the coil or affecting image quality during the RF stage; the trap circuit can block signals of specific frequencies to protect the coil or electronic equipment from interference at these frequencies; the tuning circuit makes the coil resonate at the specific frequency used by the system, which can maximize the signal strength received or transmitted at that frequency; the preamplifier motherboard is a supporting platform for the preamplifier, providing the necessary connections and power supply, as well as possible signal processing circuits; the preamplifier is used to amplify the weak signal received by the coil for subsequent processing and imaging. It should be understood that the above circuit structure is only an example, and those skilled in the art will know how to optimize the circuit structure according to their needs. To further reduce electromagnetic interaction between adjacent loops, multiple channels are arranged in an overlapping decoupling manner. That is, by physically partially overlapping the loops, mutual inductance is generated in the overlapping area to offset the coupling between the loops, reducing or eliminating interference between the loops, thereby improving the performance of the overall system.

[0033] Figure 2 shows the schematic diagram of the single-channel coil RF module in the example coil. The circuit includes capacitors, inductors, and diodes, which together form a resonant and detuning mechanism to enhance the signal or protect the RF coil when needed. Capacitor C1 and inductor L1 form the primary resonant circuit, tuning the coil to a specific Larmor frequency. Capacitors C4 and C5, along with inductor L2, can be used to further refine the resonant frequency or provide additional filtering. PIN diodes D1 and D2 (UM9989) act as fast-switching diodes, switching the coil between receive and transmit modes. Diode D3 (DH80055) can be activated during RF transmission, altering the circuit's resonant state and temporarily detuning the coil from the system's main magnetic field. This helps protect the receive coil from the intense magnetic field during RF transmission. By precisely tuning the coil to the system's operating resonant frequency, the highly selective resonance of the circuit structure shown in Figure 2 helps maximize received signal strength, prioritizing signals matching its resonant frequency to improve the signal-to-noise ratio. The detuning mechanism prevents the coil from capturing unnecessary energy when not receiving a signal, thereby reducing noise. In summary, such a single-channel design protects the coil in RF transmit mode and improves imaging quality by providing a clearer signal.

[0034] The specific component configuration and size of the design will determine its precise function and effect. In this embodiment, in order to meet the requirements of deep-level imaging of the carotid artery, the side length of the carotid coil structure unit is increased, thereby providing a deeper imaging depth. During the experiment, it was shown that after increasing the side length of the carotid coil, the imaging depth of the neck was significantly improved. Although increasing the side length of the carotid coil structure unit can ensure higher imaging quality during deep-level imaging, the surface signal-to-noise ratio will be reduced while increasing the imaging depth.

[0035] The present invention creatively proposes a wireless resonant ring unit structure that can further improve overall imaging quality. Specifically, as shown in Figure 3, the wireless resonant ring 101 also has a loop structure, primarily comprising a resonant circuit and a detuning circuit. During use, it is placed on the skin surface of the neck imaging area. The illustration uses a two-sided separate array coil as an example, requiring two wireless resonant rings, one for each of the two multi-channel carotid coils 102. Taking a four-channel carotid coil as an example, the integrated eight-channel carotid coil circuit structure includes a radio frequency coil, a detuning circuit, a tuning circuit, a preamplifier motherboard, a preamplifier, a trap circuit, and more. The wireless resonant ring 101 and the multi-channel carotid coil 102, as two unit modules, can together form a single unit, a magnetic resonance carotid array coil with a wireless resonant ring. However, this is not necessary; the wireless resonant ring 101 can also be used independently with other commercially available carotid coils that do not have a wireless resonant ring. Regardless of the form, the wireless resonant ring design enables high signal-to-noise ratio imaging of the carotid artery.

[0036] The principle circuit diagram of a wireless resonant ring is shown in Figure 4. It comprises capacitors, inductors, and diodes. Capacitors C1 and C2 store charge, providing local energy storage within the circuit or influencing the circuit's frequency response. Inductor L1 dampens current variations and, together with capacitor C1, forms a resonant circuit. Diodes D1 and D2 are used for rectification, signal modulation, and circuit protection against reverse current. During MRA imaging, the diodes switch circuit states during RF transmission, detuning the wireless resonant ring from the system's main magnetic field to prevent coil damage or image quality degradation. In signal reception mode, the diodes are turned off, allowing the wireless resonant ring to resonate at the correct frequency and maximize signal reception. To ensure optimal imaging, the diodes can be PIN diodes, Schottky diodes, or any other diode suitable for fast switching and detuning. By configuring the electronic component parameters, the resonant frequency of each wireless resonant ring is set to the desired resonant frequency. Specifically, tuning is achieved by adjusting capacitor C2 in the loop, while the frequency of the detuned loop is adjusted by adjusting capacitors C1 and L1. Of course, one or more additional electronic components can be further included to further fine-tune and match the resonant circuit, thereby achieving selective enhancement of specific frequency signals. Figure 5 is a circuit diagram of a single-sided wireless resonant ring in one embodiment, which is mainly composed of a conductive loop to form a closed loop to capture radio frequency signals. By adjusting the parameter settings of the circuit components, the wireless resonant ring is matched to the specific Larmor frequency used in the MRA system. This wireless resonant ring design is simple and efficient, and can provide high signal-to-noise ratio imaging for key areas such as the MRA carotid artery without the need for direct connection to the MRA system, thereby significantly improving imaging quality and diagnostic accuracy.

[0037] See Figure 6 of the specification for a schematic diagram of the B1+ field when a wireless resonant ring is used or when wireless resonant rings of different sizes are used. The five vertical columns from left to right correspond to the cases of not using a wireless resonant ring and using a wireless resonant ring of 3cm-6cm in size. The first row is a cross-sectional field diagram, and the second row is a coronal field diagram. As can be seen from the figure, the size of the B1+ field hardly changes after adding the wireless resonant ring. In other words, the wireless resonant ring can enhance the intensity of the signal field B1- field received by the radio frequency coil without affecting the excitation field B1+ field emitted by the radio frequency coil. Preferably, the wireless resonant ring can be placed directly in the center of the carotid coil when in use to obtain the above-mentioned effect.

[0038] See Figure 7 of the specification for a schematic diagram of received signals when a wireless resonant ring is used and when wireless resonant rings of different sizes are used. The five vertical columns, from left to right, correspond to the cases of not using a wireless resonant ring and using a wireless resonant ring of 3cm-6cm in size. The first and second rows correspond to received signals in the transverse and coronal planes, respectively. Comparing the data for using only the carotid coil and using a wireless resonant ring of 3cm-6cm in size reveals that using a wireless resonant ring can increase signal strength, with the 5cm wireless resonant ring being the most effective. Furthermore, Figure 8 provides a detailed comparison of signal reception using only the carotid coil and using a 5cm wireless resonant ring, also comparing transverse and coronal planes. Based on this comparison, a signal-to-noise ratio curve is plotted on the right side of the figure. The dashed lines in the figure show a comparison of signal-to-noise ratios. It can be seen that the signal-to-noise ratio more than doubles within 2cm of the surface and increases by approximately 50% within 2-4cm of the carotid artery, approximately below the skin. The above experimental data show that the wireless resonant ring can fully enhance the signal-to-noise ratio by increasing the size of B1- without changing the size of the transmitting field B1+, and the depth of signal enhancement and image quality are significantly improved.

[0039] In a preferred embodiment, the wireless resonant ring and the multi-channel array coil together constitute a magnetic resonance carotid array coil. As shown in FIG9 , this is a structural distribution diagram of a magnetic resonance carotid array coil with a wireless resonant ring on one side in an embodiment. Each channel in the multi-channel carotid coil 201 on one side is a loop structure. In order to further reduce the electromagnetic interaction between adjacent loops, the four channels in the figure are arranged in an overlapping decoupling manner. Furthermore, the wireless resonant ring 202 of the loop structure is placed close to the carotid coil. The wireless resonant ring 202 and the multi-channel carotid coil 201 together constitute a magnetic resonance carotid array coil. Of course, those skilled in the art will understand that in some cases, the wireless resonant ring can be used alone in conjunction with other coils.

[0040] Preferably, in this embodiment, the magnetic resonance carotid array coil also includes a resonance module 203, whose main function is to tune and match the four channels to the required Larmor frequency. Through the control of a centralized resonance module, the parameters of multiple channels can be uniformly tuned, which can ensure that the operating frequencies of all channel coils are consistent, increasing the consistency and accuracy of imaging. At the same time, this also improves the efficiency and reliability of the tuning process. By ensuring that all coils operate under optimal resonance conditions, the resonance module helps maximize the signal reception strength and reduce signal loss caused by improper tuning. Furthermore, in the presence of the wireless resonant ring 202, the resonance module 203 can cooperate with the wireless resonant ring 202. The resonance module 203 can further amplify the tuning effect based on the wireless resonant module 202's contribution to obtaining specific frequency signals, ensuring precise matching of the operating parameters of each channel, thereby providing the highest signal-to-noise ratio. The resonance module 203 is composed of electronic components, such as adjustable capacitors or inductors, microcontrollers, matching networks, radio frequency switches, etc., and these electronic components and related circuits and control systems can be electronically adjusted to automate the tuning process.

[0041] Coaxial cable 204 is used to transmit signals. Notch circuit 205 is responsible for suppressing common-mode currents in the loop. This is achieved, for example, by forming an LC circuit that resonates at a specific frequency of the undesired signal, thereby generating high impedance at that frequency and preventing the signal at that frequency from passing. Preamplifier module 206 is responsible for amplifying the signal and may include, for example, a preamplifier motherboard and a preamplifier.

[0042] The operation of a carotid magnetic resonance array coil with a wireless resonant ring is as follows: When the carotid magnetic resonance array coil is operating in the transmitting phase, the detuning circuit in the wireless resonant ring and the PIN diodes in the channel array coil's RF circuit are turned on, detuning the entire loop and preventing the RF signal from breaking down the circuit. When the carotid magnetic resonance array coil is operating in the receiving phase, the detuning circuit in the wireless resonant ring and the PIN diodes in the channel array coil's RF circuit are turned off, allowing the signal to pass. To prevent the generation of common-mode current in the loop, the coaxial cable of each coil has a trap circuit that resonates at the same Larmor frequency to reduce common-mode current.

[0043] Furthermore, the phase set by the MRA system is based on the specific phase required for optimal image reconstruction. An incorrect phase may cause artifacts or distortion in the image. To avoid this, a phase shifter is preferably used so that the signal received from the coil can be consistent with the phase set by the system, which will help to construct a correct image. In some embodiments, the signal passes through the phase shifter after passing through the trap circuit. In order to reduce the insertion loss after the module cascade, the phase shifter can use a π-type phase shifter or a T-type phase shifter. In this way, the phase of the signal received from the coil is changed to the phase set by the magnetic resonance system through the phase shifter. Preferably, the signal can also pass through an amplifier to amplify the weak magnetic resonance voltage signal received from the coil, and transmit it to the computer through the bed for signal post-processing to complete the subsequent reconstruction of the image.

[0044] In some embodiments, the optimal placement of the wireless resonant ring is axially symmetrical with the carotid array coil. This configuration minimizes the effects of coupling between the two. The wireless resonant ring can effectively enhance the signal-to-noise ratio by increasing the size of B1- without changing the size of the transmit field B1+. The signal enhancement depth can cover the carotid bifurcation, thereby improving the image signal-to-noise ratio and image quality.

[0045] In general, the present invention does not need to limit the position, size, number of channels and dimensions of the carotid coil, nor does it need to limit the position, size, number of channels and dimensions of the wireless resonant ring. Those skilled in the art will understand that the above parameters of the carotid coil and the wireless resonant ring can be flexibly configured according to the requirements of the imaging scene. As long as they comply with the working principles described in the above embodiments, a good imaging signal-to-noise ratio and imaging images of a certain depth can be obtained. The placement of the carotid coil and the wireless resonant ring can be directly placed close to each other or at a certain distance, all of which are included in the inventive concept of the present invention.

[0046] In summary, the present invention can ensure that higher imaging quality can be provided at a sufficient imaging depth by increasing the side length of the carotid coil structural unit. However, while increasing the imaging depth, the surface signal-to-noise ratio will be reduced. At this time, a wireless resonant ring is used on the carotid coil. The wireless resonant ring can enhance the imaging depth to meet not only the carotid bifurcation position, but also the common carotid artery imaging. After using the wireless resonant ring, the carotid artery imaging effect can be significantly improved, making it easier for doctors to diagnose.

[0047] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A wireless resonant loop for a magnetic resonance carotid artery imaging system, characterized in that, Comprising: At least one conductive loop, forming a closed-loop structure; A resonant circuit composed of at least one capacitor and at least one inductor; And at least two diodes to form a detuning mechanism.

2. The wireless resonance loop according to claim 1, wherein It further includes a tuning capacitor connected to the conductive loop.

3. The wireless resonant loop according to claim 1 or 2, characterized in that, The type of the diode is selected from PIN diodes or Schottky diodes.

4. A magnetic resonance carotid artery array coil, comprising a carotid artery array coil and a wireless resonant loop according to any one of claims 1-3; The carotid artery array coil is a loop structure.

5. The magnetic resonance carotid artery array coil according to claim 4, wherein The carotid artery array coil is a multi-channel array coil and includes at least one capacitor, at least one inductor, and at least two diodes that constitute a resonance and detuning mechanism.

6. The magnetic resonance carotid artery array coil according to claim 5, characterized in that, It further includes a resonance module that cooperates with the carotid artery array coil and the wireless resonant loop and is used to tune and match the loops of multiple channels to the required Larmor frequency.

7. The magnetic resonance carotid artery array coil according to claim 6, characterized in that, The multiple channels of the multi-channel array coil are arranged in an overlapping and decoupled manner.

8. The magnetic resonance carotid artery array coil according to any one of claims 4-7, wherein It further includes a notch circuit connected by a cable and is used to suppress the common-mode current in the loop.

9. The magnetic resonance carotid artery array coil according to claim 8, wherein, A phase shifter is connected after the notch circuit, and the phase shifter adopts a π-type phase shifter or a T-type phase shifter.

10. A magnetic resonance imaging method using the wireless resonant loop according to any one of claims 1-3, comprising the following steps: S1. Position the wireless resonant loop in the patient's neck area; position the wireless resonant loop and the carotid artery array coil; S2. Adjust the wireless resonant loop to resonate at the Larmor frequency set by the magnetic resonance imaging system; S3. Perform a magnetic resonance imaging scan, capture the signal enhanced by the wireless resonant loop; process the captured signal to generate an image of the carotid artery area.

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