Wireless wearable coil for magnetic resonance imaging

Abstract

The invention discloses a wireless wearable coil for magnetic resonance imaging, and belongs to the technical field of magnetic resonance, the wireless wearable coil comprises a detuning adjustment module, a first matching capacitor C2 and a second matching capacitor C3, the detuning adjustment module comprises an inductor L1, a tuning capacitor C1 and a diode assembly, the diode assembly is matched with the detuning adjustment module, and the first matching capacitor C2 and the second matching capacitor C3 are matched with each other. Switching between a detuning state of the wireless wearable coil in a transmitting mode and a tuning state in a receiving mode is realized; when the wireless wearable coil is in a transmitting mode, the diode assembly is switched on, the inductor L1 in the detuning adjusting module resonates with the tuning capacitor, and the wireless wearable coil is detuned. When the wireless wearable coil is in a receiving mode, the diode assembly is cut off, the detuning adjusting module is disconnected, current flows through the tuning capacitor C1, the first matching capacitor C2 and the second matching capacitor C3, and the wireless wearable coil keeps a resonance state and is used for receiving signals. The method has the effect of optimizing the signal quality in the magnetic resonance imaging process.

Description

Technical Field

[0001] This application relates to the technical field of magnetic resonance, and particularly relates to a wireless wearable coil for magnetic resonance imaging. Background Art

[0002] Ocular magnetic resonance imaging (MRI) is essential for the detailed, non-invasive visualization of ocular structures, contributing to the diagnosis and treatment of diseases such as optic nerve lesions, ocular tumors, and retinal problems. Its superior soft tissue contrast and radiation-free characteristics make it an ideal choice for repeated imaging.

[0003] However, traditional ocular imaging MRI devices typically rely on head coils, which have certain limitations for detailed ocular imaging because the coil elements responsible for receiving signals from the eye region are large and generally lack close conformity with the eyes. Due to the distance attenuation effect of the standard head coil, the signal intensity in the ocular region is only 30 - 40% of the theoretical value; and the planar coil is mismatched with the curved surface morphology of the eyeball, resulting in signal blind spots in more than 30% of the area. Summary of the Invention

[0004] In view of the deficiencies in the prior art, this application provides a wireless wearable coil for magnetic resonance imaging, which can be compatible with a local head receiving array and uses near-field coupling to significantly improve the signal-to-noise ratio.

[0005] The technical solution for this application to solve the above technical problems is as follows: A wireless wearable coil for magnetic resonance imaging includes a detuning adjustment module, a first matching capacitor C2, and a second matching capacitor C3. The detuning adjustment module includes an inductor L1, a tuning capacitor C1, and a diode assembly. The diode assembly cooperates with the detuning adjustment module to achieve the switching between the detuned state of the wireless wearable coil in the transmission mode and the tuned state in the reception mode. When in the transmission mode, the diode assembly conducts, the inductor L1 in the detuning adjustment module resonates with the tuning capacitor C1, and the wireless wearable coil is detuned. When in the reception mode, the diode assembly is cut off, the detuning adjustment module is open-circuited, and the current flows through the tuning capacitor C1, the first matching capacitor C2, and the second matching capacitor C3, and the wireless wearable coil maintains a resonant state for receiving signals.

[0006] Further, the wireless wearable coil is an ocular wireless coil. The ocular wireless coil includes two detuning adjustment modules and two first matching capacitors C2. Among them, one detuning adjustment module and one first matching capacitor C2 correspond to one eye, and the other detuning adjustment module and the other first matching capacitor C2 correspond to the other eye.

[0007] Further, the diode assembly includes a pair of PIN diodes connected in bidirectional reverse parallel. The inductor L1 is connected in series with the diode assembly. The tuning capacitor C1 is connected in series with the first matching capacitor C2 and the second matching capacitor C3. The tuning capacitor C1 is connected in parallel with the inductor L1 and the diode assembly. Two decoupling capacitors C4 are provided between the two second matching capacitors C3. The two ends of the decoupling capacitor C4 are respectively connected to the same side of the two second matching capacitors C3. The second matching capacitor C3 and the decoupling capacitor C4 are used for capacitive decoupling between the two detuning modules. The passive detuning of the circuit is achieved by the cut-off or conduction state of the PIN diode.

[0008] Further, the resonance frequency of the coil is determined by the detuning adjustment module composed of an inductor and a capacitor. By utilizing the conduction and cut-off characteristics of the diode assembly, the equivalent capacitance or inductance value of the detuning adjustment module can be dynamically changed, and the resonance frequency can be actively or passively adjusted.

[0009] Further, when in the transmission mode, the diode is conducting. The inductor L1 and the tuning capacitor C1 in the detuning module form a parallel resonance circuit, and its impedance expression is: , where, Z ω represents the impedance at an angular frequency of ω, reflecting the characteristics of the circuit's obstruction to alternating current and phase influence. j is the imaginary unit, and ω represents the angular frequency; At this time, the inductor L1 and the tuning capacitor C1 are in resonance, , , tends to infinity, and the circuit behaves as a high-impedance open circuit; When in the receiving mode, the diode is cut off. The distributed inductance L inherent in the coil, the tuning capacitor C1, the first matching capacitor C2, and the second matching capacitor C3 form a series resonance circuit, and its impedance expression is: , At this time, the inductor L, the tuning capacitor C1, the first matching capacitor C2, and the second matching capacitor C3 are in resonance, , tends to 0, Z ω tends to 0, and the circuit behaves as a low impedance; At this time, the resonance frequency of the coil is: .

[0010] Further, the structure of the coil is adapted to the contour of the human eye and is prepared from a flexible material.

[0011] Further, the amplitude of the induced voltage in the transmission stage is: ; where, represents the emission field strength, ; A represents the coil area; the amplitude of the induced voltage is higher than the conduction threshold of the PIN diode to ensure reliable triggering.

[0012] In summary, compared with the prior art, the beneficial effects of the above technical solutions are: A wireless wearable coil for magnetic resonance imaging according to the present application can, through the cooperation of the diode assembly and the detuning adjustment module, achieve that the frequency of the detuning adjustment module deviates from the Larmor frequency in the transmission mode to suppress radio frequency energy absorption, reduce heat loss and interference, and restore the resonant matching state in the reception mode to ensure signal reception sensitivity. Combining the wireless wearable design improves patient comfort and device compatibility, effectively optimizes the signal quality and safety in the magnetic resonance imaging process, and has both the high efficiency of dynamic tuning and the flexibility of clinical application. Description of the Drawings

[0013] Figure 1 is a schematic diagram of a glasses-shaped wireless coil for eye imaging; Figure 2 is a schematic structural diagram of a glasses-shaped wireless coil designed for eye imaging; Figure 3 is a schematic structural diagram of a headset-shaped wireless coil designed for ear imaging; Figure 4 is the B1 + field distribution diagram in a human head model under the condition that the Nova 32-channel receiving array does not load the wireless goggle coil; Figure 5 is the B1 + field distribution diagram in a human head model under the condition that the Nova 32-channel receiving array loads the wireless goggle coil; Figure 6 is the measured SNR distribution diagram of the central axis plane of the eye in a human head model. Among them, (A) is the axial SNR comparison diagram of the Nova 32-channel receiving array with / without the wireless goggle coil, and (B) is the one-dimensional SNR curve diagram extracted along the Figure 6 dashed line direction in (A); Figure 7 is the measured SNR distribution diagram of the central axis plane of the ear in a human head model. Among them, (A) is the axial SNR comparison diagram of the Nova 32-channel receiving array with / without the headset coil, and (B) is the one-dimensional SNR curve diagram extracted along the Figure 7 dashed line direction in (A).

[0014] Description of the reference numerals: 1. Detuning adjustment module; 2. Frame; 3. Temple; 4. Nose pad; 5. Cover. Detailed Embodiments

[0015] The principles and features of the present application will be described below in conjunction with the accompanying drawings. The examples given are only for explaining the present application and are not intended to limit the scope of the present application.

[0016] An embodiment of the present application discloses a wireless wearable coil for magnetic resonance imaging.

[0017] Referring to Figure 1 , a wireless wearable coil for magnetic resonance imaging includes: a detuning adjustment module 1, a first matching capacitor C2, and a second matching capacitor C3. The detuning adjustment module 1 includes an inductor L1, a tuning capacitor C1, and a diode assembly. The diode assembly cooperates with the detuning adjustment module 1 to realize the switching between the detuned state of the wireless wearable coil in the transmission mode and the tuned state in the reception mode. When in the transmission mode, the diode assembly conducts, the inductor L1 in the detuning adjustment module resonates with the tuning capacitor C1, and the wireless wearable coil is detuned. When in the reception mode, the diode assembly is cut off, the detuning adjustment module is open-circuited, and the current flows through the tuning capacitor C1, the first matching capacitor C2, and the second matching capacitor C3, and the wireless wearable coil maintains a resonant state for receiving signals.

[0018] The detuning adjustment module 1 realizes the precise coupling of the resonant frequency and the Larmor frequency in the reception mode through the matching of the inductor and the tuning capacitor C1, significantly enhancing the image signal-to-noise ratio. The diode assembly conducts in the transmission mode to form a low-impedance path, triggering the detuning adjustment module 1 to connect the first matching capacitor C2 or short-circuit part of the inductor, so that the resonant frequency deviates from the Larmor frequency, effectively suppressing the absorption of radio frequency energy, reducing heat loss and interference, and at the same time ensuring that the circuit maintains a high-impedance resonant state when the reception mode is cut off. The detuning adjustment module 1 dynamically changes the capacitance or inductance value to make the resonant frequency far away from the resonance region during the transmission stage, and cooperates with the diode assembly to achieve efficient switching between the two modes, which not only ensures the imaging safety but also improves the signal acquisition efficiency. The three work together to make the coil have the dual advantages of high-sensitivity imaging and low radio frequency risk, and can effectively improve the SNR in the eye region and achieve the bionic fitting of the eyeball curved surface shape (spacing ≤ 3 mm).

[0019] The wireless wearable coil is an eye wireless coil. The eye wireless coil includes two detuning adjustment modules 1, two first matching capacitors C2, and two second matching capacitors C3. Among them, one detuning adjustment module 1 and a group of first matching capacitors C2 and second matching capacitors C3 correspond to one eye, and the other detuning adjustment module 1 and another group of first matching capacitors C2 and second matching capacitors C3 correspond to the other eye. The present invention is a special goggle-type wireless coil designed for the optic nerve in the magnetic resonance field; similar circuit designs can also be used for the design of special wireless coils for parts such as the thyroid and oral cavity.

[0020] In the described eye wireless coil, two detuning adjustment modules 1 correspond to the binocular region, respectively. Independent inductors and tuning capacitors C1 are used to match the Larmor frequency of ocular tissue. This improves the local signal-to-noise ratio (SNR) of both eyes in receive mode, allowing for accurate capture of magnetic resonance signals from fine structures such as the optic nerve and retina. Two diode components are connected in series with the inductors. Leveraging their rapid on / off characteristics, they simultaneously conduct in transmit mode, triggering the detuning adjustment module 1 to connect in parallel with the first matching capacitor C2 or short-circuit part of the inductor, causing the resonant frequency to synchronously deviate from the Larmor frequency. This effectively suppresses the absorption of radio frequency energy by ocular tissue, reduces local SAR values, and minimizes electromagnetic crosstalk between the bilateral coils. This modular design, through unified control of the detuning adjustment module 1, not only achieves high-resolution imaging of the binocular region but also rapidly adapts to the curved contours of areas such as the thyroid gland and oral cavity by adjusting LC parameters and structural morphology. This demonstrates the flexibility and efficiency of cross-regional applications while maintaining an improved SNR and radio frequency safety.

[0021] The diode assembly comprises a pair of bidirectional, anti-parallel PIN diodes. The inductor L1 is connected in series with the diode assembly, and the tuning capacitor C1 is connected in series with the first matching capacitor C2 and the second matching capacitor C3. The tuning capacitor C1 is connected in parallel with the inductor L1 and the diode assembly. Two decoupling capacitors C4 are located between the two second matching capacitors C3. The two ends of the decoupling capacitors C4 are connected to the same side of the two second matching capacitors C3, forming a "mouth"-shaped structure. The second matching capacitors C3 and the decoupling capacitors C4 serve to decouple the capacitance between the two detuning adjustment modules 1. Passive detuning of the circuit is achieved by switching the PIN diodes between the cutoff and on states. The coil has an overall diameter of 15 cm, covering the entire eye area. The two symmetrical coils have a diameter of 6.3 cm and act on the optic nerve. Four capacitors at the nose pad 4 serve to match the circuit and decouple the two channels. The PIN diodes feature fast switching, low on-resistance to ensure a deep detuning depth, and high breakdown voltage to withstand high-voltage pulses during the transmission phase. The coil inductor L needs to use a high permeability, low-loss magnetic core (such as ferrite) to avoid magnetic saturation during the transmission phase.

[0022] In the eye wireless coil, the diode assembly uses a pair of PIN diodes connected in bidirectional reverse parallel (such as MA4P7446F). Utilizing its fast switching characteristics, it presents a high-impedance cut-off state in the receiving mode, enabling the tuning capacitor C1, the first matching capacitor C2, and the inductor to form a precise resonant circuit (the resonant frequency matches the Larmor frequency of eye tissues), and can distinguish nerve fiber lesions at the 0.08 mm level; in the transmitting mode, the diode conducts and presents a low impedance, triggering the second matching capacitor C3 and the decoupling capacitor C4 to be connected to the circuit. Through the series connection of the second matching capacitor C3 with the tuning capacitor C1 and the first matching capacitor C2 and the decoupling capacitor C4 bridging the two channels, the total capacitance is increased to 1.8 times the original tuning capacitor C1, the resonant frequency deviates from the Larmor frequency by 15%, the electromagnetic coupling between the bilateral coils is synchronously reduced, and with the <10Ω on-resistance and >100V breakdown voltage of the PIN diode, the detuning depth and the high-voltage pulse tolerance are ensured; Refer to Figure 2 , the eye wireless coil is integrated in the spectacle frame 2. The second matching capacitor C3 and the decoupling capacitor C4 are located at the nose pad 4 position, and the detuning adjustment module 1 and the diode assembly are located at the connection position of the spectacle frame 2 and the temple 3; the four matching capacitors at the nose pad 4 position further eliminate the mutual inductance interference between the two channels, increasing the isolation between the left and right eye coils to more than 30 dB. Cooperating with the symmetrically distributed 6.3 cm diameter optic nerve targeting coils, high-resolution independent imaging of the bilateral optic nerves is achieved. At the same time, through the anti-magnetic saturation design of the ferrite core, the inductance loss during the transmitting stage is reduced to less than 0.5%, with both the precise diagnosis and the safe and efficient dual performance. Refer to Figure 3 , the detuning adjustment module 1 can be integrated in the housing 5 of the earcup. In addition, this modular design can also be directly reused for curved parts such as the thyroid and oral cavity, and can quickly adapt to the imaging requirements of different tissues by adjusting the capacitance parameters and the core shape.

[0023] The resonant frequency of the coil is determined by the detuning adjustment module 1 composed of an inductor and a capacitor. Utilizing the on and off characteristics of the diode assembly, the equivalent capacitance or inductance value of the detuning adjustment module 1 is dynamically changed, and the resonant frequency can be actively or passively adjusted.

[0024] In the coil, the detuning adjustment module 1 forms a fixed resonance frequency through the series combination of an inductor and a tuning capacitor C1 when the diode is cut off, precisely matching the Larmor frequency of the eye tissue; when the diode assembly conducts in the transmission mode, it triggers the detuning adjustment module 1 to parallelly connect a first matching capacitor C2 or short-circuit a part of the inductor, and the resonance frequency decreases according to the formula, moving away from the resonance interval to suppress the absorption of radio frequency energy. At the same time, with a conduction resistance of < 10Ω, it ensures the detuning depth, and a breakdown voltage of > 100V can withstand the high-voltage pulse during transmission; the nose pad matching capacitor further eliminates the coupling between the two channels, enabling the isolation degree between the left and right coils to reach 35dB. In combination with the symmetric 6.3 cm diameter targeted coil, it realizes independent high-resolution imaging of the bilateral optic nerves. Moreover, the anti-magnetic saturation design of the ferrite core controls the transmission loss within 0.3%. This dynamic tuning mechanism switches the capacitance / inductor parameters in real time, ensuring both the signal accuracy during reception and the safe detuning during transmission, providing a dedicated imaging solution with both high efficiency and safety for parts such as the eyes and thyroid glands.

[0025] Furthermore, when in the transmission mode, the diode conducts, and the inductor L1 and the tuning capacitor C1 in the detuning module form a parallel resonance circuit, and its impedance expression is: , where, Z ω represents the impedance (complex impedance) at an angular frequency of ω, reflecting the characteristics of the circuit's obstruction to alternating current and phase influence. j is the imaginary unit, and ω represents the angular frequency, describing the speed of change of sinusoidal alternating current; At this time, the inductor L1 and the tuning capacitor C1 resonate, , , tends to infinity, and the circuit behaves as a high-impedance open circuit; When in the reception mode, the diode is cut off, and the inherent distributed inductor L in the coil, the tuning capacitor C1, the first matching capacitor C2, and the second matching capacitor C3 form a series resonance circuit, and its impedance expression is: , At this time, the inductor L, the tuning capacitor C1, the first matching capacitor C2, and the second matching capacitor C3 resonate, , tends to 0, and Z ω tends to 0, and the circuit behaves as a low impedance; At this time, the resonance frequency of the coil is: .

[0026] The self-triggering mechanism of the diode is as follows: Reception mode (low field strength): The induced voltage of the coil is relatively low (usually < 0.7V), and the PIN diode is in the reverse-biased cut-off state, and the circuit maintains the tuned state ( ).

[0027] Transmission mode (high field strength): Coil induced voltage Significantly increased (up to dozens of volts), the PIN diode is forward-biased and conducts, forming a low-impedance path, connecting the first matching capacitor C2 to the circuit to achieve detuning.

[0028] The structure of the coil adapts to the contour of the human eye, is prepared with a flexible material, specifically using 3D printed medical-grade polycarbonate material. The inner surface curvature radius of the coil is 7.8 mm (matching the average corneal curvature), and a nose pad pressure buffer layer (0.5 mm thick silicone) is integrated.

[0029] Through structural and material innovations, the eye wireless coil deeply integrates functional modules with ergonomics, making the gap between the coil and the eye skin < 0.3 mm, improving the signal coupling efficiency by 40%, effectively reducing the magnetic field attenuation caused by the air layer, and further enhancing the signal-to-noise ratio of eye tissues in the receiving mode. The biocompatibility and metal-free allergy characteristics of the flexible material enable it to directly contact the sensitive skin around the eyes. Combined with the lightweight design, it significantly improves the examination tolerance of pediatric and critically ill patients. This structural design not only provides a stable magnetic field coupling environment for the detuning adjustment module 1, but also through human-machine engineering optimization, improves the clinical operation success rate from 75% of traditional rigid coils to 98%, becoming the key hardware support for accurate eye MRI diagnosis.

[0030] The amplitude of the induced voltage in the transmission stage is: ; where represents the transmission field strength, , A represents the coil area; the amplitude of the induced voltage is higher than the conduction threshold of the PIN diode to ensure reliable triggering.

[0031] Through the precise matching of electromagnetic induction and circuit triggering by the coil, the full-automatic and reliable switching between the transmission / receiving modes is realized: The detuning adjustment module 1 senses the radio frequency field energy in the transmission stage, ensuring that the diode component quickly conducts forward under high field strength, triggering the detuning adjustment module 1 to connect the first matching capacitor C2 in parallel, increasing the total capacitance and reducing the resonance frequency, effectively moving away from the Larmor frequency to suppress radio frequency energy absorption, and controlling the specific absorption rate (SAR) below 0.6 W / kg; in the low field strength receiving mode, the induced voltage < 0.7 V, the diode is reverse cutoff and presents a high impedance (> 10 kΩ), and the LC circuit only contains the tuning capacitor C1 to improve the signal sensitivity through precise resonance.

[0032] This self-triggering mechanism eliminates the need for an external control circuit. It autonomously drives mode switching through electromagnetic induction energy, combines the high breakdown voltage tolerance of PIN diodes to emit high-voltage pulses, ensures no failure after tens of thousands of scans, provides stable and reliable detuning-resonance dynamic regulation for magnetic resonance imaging, is especially suitable for long-term continuous scanning, eliminates the risk of misoperation in manual switching at the hardware level while improving imaging efficiency, and becomes the core technical support for the clinical automation of wireless wearable coils.

[0033] 7T verification refers to the process of verifying the performance and testing of equipment or designs in a 7 Tesla (7T) high-field magnetic resonance imaging (MRI) environment. The coil has been verified on a 7T magnetic resonance instrument and can be used together with Nova32 (a 32-channel head transmit coil). (Radiofrequency transmit field) experiments were conducted on a 298 MHz head-shaped phantom simulating human tissue using the DREAM ( Fast magnetic resonance imaging technique for field mapping) method and SNR (signal-to-noise ratio) testing to verify the performance of the design. SNR was calculated based on gradient echo (GRE) images with the following parameters: FOV (field of view) = 250 × 250 mm2, slice thickness = 5 mm, nominal flip angle = 70 degrees, TR / TE (repetition time / echo time) = 1000 / 2 ms. SNR was determined using Kellman (a method for calculating SNR considering the statistical characteristics of noise), taking into account the noise correlation matrix.

[0034] Figure 4 and Figure 5 show the measured distribution maps of the Figure 4 field on the surface of a human head model in a 32-channel transceiver integrated head radiofrequency array without using ( Figure 5 ) and using ( ) the wireless coil. Figure 4 and Figure 5 compare the multi-slice axial maps of the Nova coil (a Philips head 7T dedicated coil), including the cases of not using and using wireless goggles. Since the wireless goggles cannot be removed casually during the magnetic resonance scanning stage, they remain "invisible" to the radiofrequency field during radiofrequency (RF) transmission, resulting in negligible changes in the

[0035] Figure 6 field. With the same input power, the difference in the average flip angle on the head-shaped phantom with and without wireless goggles is less than 5%. Figure 6(A) shows the measured axial SNR distribution maps of the Nova 32-channel receive array, including the individual Nova 32 receive array and when used in combination with wireless goggles. 6 (B) shows the one-dimensional SNR curves of the Nova 32-channel receive array, including the individual Nova 32 receive array and when used in combination with wireless goggles, with an approximately 4-fold improvement in SNR in the surface region and still a 1.5-fold SNR improvement at 2.5 cm subcutaneously, resulting in a significant improvement in image quality and clarity. This enhancement is particularly evident in more clearly showing fine eye structures such as the retina and surrounding tissues.

[0036] Figure 7 Shows the measured distribution map and one-dimensional SNR curve of the SNR on the surface of a human head model in the axial direction in a 32-channel transceiver integrated head radiofrequency array, with and without the use of a wireless coil. Figure 7 (A) shows the measured axial SNR distribution maps of the Nova 32-channel receive array, including the individual Nova 32 receive array and when used in combination with ear wireless coils. 7 (B) shows the one-dimensional SNR curves of the Nova 32-channel receive array, including the individual Nova 32 receive array and when used in combination with ear wireless coils, with an approximately 2.2-fold improvement in SNR in the surface region and still a 2-fold SNR improvement at 1.2 cm subcutaneously, resulting in a significant improvement in image quality and clarity. This enhancement is particularly evident in more clearly showing fine structures such as the ear and surrounding tissues.

[0037] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A wireless wearable coil for magnetic resonance imaging, characterized in that Comprising: A detuning adjustment module (1), a first matching capacitor C2, and a second matching capacitor C3. The detuning adjustment module (1) includes an inductor L1, a tuning capacitor C1, and a diode assembly. The diode assembly cooperates with the detuning adjustment module (1) to achieve the switching between the detuned state of the wireless wearable coil in the transmission mode and the tuned state in the reception mode. When in the transmission mode, the diode assembly is turned on, the inductor L1 and the tuning capacitor C1 in the detuning adjustment module resonate, and the wireless wearable coil is detuned. When in the reception mode, the diode assembly is turned off, the detuning adjustment module is open-circuited, and the current flows through the tuning capacitor C1, the first matching capacitor C2, and the second matching capacitor C3, and the wireless wearable coil remains in the resonant state for receiving signals.

2. The wireless wearable coil for magnetic resonance imaging according to claim 1, characterized in that: The wireless wearable coil is an eye wireless coil. The eye wireless coil includes two detuning adjustment modules (1), two first matching capacitors C2, and two second matching capacitors C3. Among them, one detuning adjustment module (1) and a set of first matching capacitor C2 and second matching capacitor C3 correspond to one eye, and the other detuning adjustment module (1) and the other set of first matching capacitor C2 and second matching capacitor C3 correspond to the other eye.

3. The wireless wearable coil for magnetic resonance imaging according to claim 2, wherein: The diode assembly includes a pair of PIN diodes connected in bidirectional reverse parallel. The inductor L1 is connected in series with the diode assembly. The tuning capacitor C1 is connected in series with the first matching capacitor C2 and the second matching capacitor C3. The tuning capacitor C1 is connected in parallel with the inductor L1 and the diode assembly. Two decoupling capacitors C4 are provided between the two second matching capacitors C3. The two ends of the decoupling capacitor C4 are respectively connected to the same side of the two second matching capacitors C3. The second matching capacitor C3 and the decoupling capacitor C4 are used for capacitive decoupling between the two detuning adjustment modules (1). The passive detuning of the circuit is achieved through the cut-off or conduction state of the PIN diode.

4. The wireless wearable coil for magnetic resonance imaging according to claim 1, characterized in that: The resonant frequency of the coil is determined by the detuning adjustment module (1) composed of an inductor and a capacitor. By utilizing the on and off characteristics of the diode assembly, the equivalent capacitance or inductance value of the detuning adjustment module (1) can be dynamically changed, and the resonant frequency can be actively or passively adjusted.

5. A wireless wearable coil for magnetic resonance imaging according to claim 1, wherein: When in the transmission mode, the diode is turned on, and the inductor L1 and the tuning capacitor C1 in the detuning module form a parallel resonant circuit, and its impedance expression is: ， Among them, Z ω represents the impedance at an angular frequency of ω, reflecting the characteristics of the circuit's obstruction to alternating current and phase influence. j is the imaginary unit, and ω represents the angular frequency; At this time, the inductor L1 resonates with the tuning capacitor C1, , , tends to infinity, and the circuit behaves as a high-impedance open circuit; When in the reception mode, the diode is turned off, and the inherent distributed inductor L in the coil, the tuning capacitor C1, the first matching capacitor C2, and the second matching capacitor C3 form a series resonant circuit, and its impedance expression is: ， At this time, the inductor L resonates with the tuning capacitor C1, the first matching capacitor C2 and the second matching capacitor C3. , tends to 0, Z ω tends to 0, the circuit exhibits low impedance; At this time, the coil resonant frequency is: .

6. The wireless wearable coil for magnetic resonance imaging according to claim 1, characterized in that: The structure of the coil is adapted to the contour of the human eye and is prepared from a flexible material.

7. The wireless wearable coil for magnetic resonance imaging according to claim 3, wherein: Inductive voltage amplitude during the launch phase is: ; where represents the launch field intensity ; A represents the coil area; the inductive voltage amplitude is higher than the conduction threshold of the PIN diode to ensure reliable triggering.

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