Coil assembly, magnetic resonance imaging system and tuning method
By setting a variable capacitor and a tuning controller in the stretchable radio frequency receiving coil element of the magnetic resonance imaging system, the capacitance value is adjusted to maintain the stability of the resonance frequency, and the problem of the resonance frequency change of the coil element in the stretched state is solved, and the stability of the coil performance is achieved.
Patent Information
- Application Number
- CN202311101304.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-29
- Publication Date
- 2025-02-28
AI Technical Summary
In magnetic resonance imaging systems, the resonant frequency of the coil element changes with the inductance of the conductor, causing fluctuations in the coil performance, especially when the stretchable coil element is in the tensile state.
By providing a variable capacitor and a tuning controller in the coil assembly, the capacitance value of the stretchable radio frequency receiving coil element is adjusted so that its resonant frequency is within a preset range.
The coil element maintains a stable resonant frequency and performance under the tensile state, and avoids performance fluctuations caused by inductance changes.
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Figure CN119535313A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of medical devices, and in particular to a coil assembly, a magnetic resonance imaging system and a tuning method. Background Art
[0002] Magnetic resonance imaging (MRI) is a technology that uses the magnetic resonance phenomenon to perform imaging. MRI equipment transmits radio frequency (RF) pulses of a specific frequency to a subject in a static magnetic field through a radio frequency coil to induce nuclear magnetic resonance of hydrogen protons in the subject's body, and obtains magnetic resonance images of the human body by receiving the human body's magnetic resonance signals.
[0003] Generally, the magnetic resonance signals generated by the human body are collected by using a receiving coil. When working, the receiving coil can be arranged close to the human body to receive the magnetic resonance signals of the corresponding parts of the object under test.
[0004] The methods described in this section are not necessarily methods that have been previously conceived or employed. Unless otherwise indicated, it should not be assumed that any method described in this section is considered to be prior art simply because it is included in this section. Similarly, unless otherwise indicated, the issues mentioned in this section should not be considered to have been recognized in any prior art. Summary of the invention
[0005] In view of this, a first aspect of the present disclosure proposes a coil assembly, comprising: at least one stretchable RF receiving coil element, each of the at least one stretchable RF receiving coil element comprising a variable capacitor, the variable capacitor being used to adjust the resonant frequency of the corresponding stretchable RF receiving coil element; and a tuning controller, the tuning controller being at least configured to adjust the capacitance value of the variable capacitor of each of the at least one stretchable RF receiving coil elements so that the resonant frequency of the at least one stretchable RF receiving coil element is within a preset range.
[0006] A second aspect of the present disclosure provides a magnetic resonance imaging system, comprising the above coil assembly.
[0007] A third aspect of the present disclosure proposes a tuning method for a magnetic resonance imaging system according to the second aspect, comprising: sending at least one first signal to at least one stretchable RF receiving coil element; receiving at least one second signal from the at least one stretchable RF receiving coil element, wherein the at least one second signal is a signal returned after the at least one first signal passes through a corresponding one of the at least one stretchable RF receiving coil elements; and adjusting the capacitance value of the variable capacitor of each of the at least one stretchable RF receiving coil elements using a tuning controller according to the second signal to adjust the resonant frequency of the at least one stretchable RF receiving coil element until the resonant frequency of the at least one stretchable RF receiving coil element is adjusted to within a preset range.
[0008] According to an embodiment of the present disclosure, by providing a variable capacitor and a tuning controller in a coil component, it is achieved to adjust a stretchable radio frequency receiving coil element to a resonant state with a simple structure.
[0009] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can better understand the above and other features and advantages of the present disclosure. In the accompanying drawings:
[0011] Figure 1 A schematic diagram showing a coil assembly of some embodiments of the present disclosure is shown;
[0012] Figure 2 Schematic diagrams showing coil assemblies of other embodiments of the present disclosure;
[0013] Figure 3 Schematic diagrams showing coil assemblies of other embodiments of the present disclosure;
[0014] Figure 4 shows a functional block diagram of a tuning controller according to an embodiment of the present disclosure;
[0015] Figure 5 A schematic flow chart showing a tuning method for a magnetic resonance imaging system according to some embodiments of the present disclosure; and
[0016] Figure 6 A schematic flow chart of a tuning method for a magnetic resonance imaging system according to other embodiments of the present disclosure is shown.
[0017] Description of reference numerals:
[0018] 10 Coil Assembly
[0019] 100 stretchable RF receiving coil elements
[0020] 102, 102a, 102b, 102n variable capacitors
[0021] 104, 104a, 104b, 104n directional coupler
[0022] 106, 106a, 106b, 106n first capacitor
[0023] 108, 108a, 108b, 108n second capacitor
[0024] 110, 110a, 110b, 110n low noise amplifier LNA or low noise converter LNC
[0025] 112 Stretchable Conductor
[0026] 122 First Signal
[0027] 124 Second Signal
[0028] 200 Tuning Controller
[0029] 30 Magnetic Resonance System
[0030] 40 Body Coil
[0031] 50 Measurement and reconstruction system
[0032] 310 first signal conversion module
[0033] 320 programmable logic modules
[0034] 330 Digital Integrated Module
[0035] 340 second signal conversion module
[0036] 126 Control voltage DETAILED DESCRIPTION
[0037] In order to have a clearer understanding of the technical features, purposes and effects of the present disclosure, specific embodiments of the present disclosure are now described with reference to the accompanying drawings, in which the same reference numerals represent the same parts.
[0038] In this document, “exemplary” means “serving as an example, instance or illustration”, and any diagram or implementation described in this document as “exemplary” should not be interpreted as a more preferred or more advantageous technical solution.
[0039] In the present disclosure, unless otherwise specified, the use of the terms "first", "second", etc. to describe various elements is not intended to limit the positional relationship, timing relationship, or importance relationship of these elements, and such terms are only used to distinguish one element from another element. In some examples, the first element and the second element may refer to the same instance of the element, and in some cases, based on the description of the context, they may also refer to different instances.
[0040] The terms used in the description of various examples in this disclosure are only for the purpose of describing specific examples and are not intended to be limiting. Unless the context clearly indicates otherwise, if the number of elements is not specifically limited, the element can be one or more. In addition, the term "and / or" used in this disclosure covers any one of the listed items and all possible combinations.
[0041] A magnetic resonance imaging system generally includes a cavity magnet (such as a superconducting magnet) for providing a static magnetic field, a cavity gradient coil inside the magnet, a cavity body coil inside the gradient coil, a bed on which a subject is placed, and coil elements for receiving magnetic resonance signals from the subject.
[0042] The coil element can be constructed as a local coil arranged close to the object under test, such as a spinal coil installed at the bed position of the magnetic resonance imaging device, an abdominal coil or a chest coil covering the abdomen or chest of the object under test, and various other local coils covering a certain part of the object under test, such as a knee coil, a shoulder coil, a wrist coil, a body array coil, a head and neck coil, etc., to receive the magnetic resonance signal returned from the object under test. Specifically, the coil element can be excited in a tuned state to receive the magnetic resonance signal generated by the object under test under the excitation of the high-frequency electromagnetic wave signal or other high-frequency / radio frequency electromagnetic wave signals returned by the object under test.
[0043] In addition to receiving magnetic resonance signals from the corresponding parts of the object being measured, coil elements such as abdominal coils, spine coils and chest coils can also be used to monitor some important organs with periodic physiological motion signals, such as the heart and lungs, because they are closer to the corresponding parts of the object being measured.
[0044] In recent years, research on coil elements has increased, and the stretchable flexible conductors of coil elements in wearable coil devices have gradually become the focus of research in the field of magnetic resonance imaging. Studies have found that during the stretching process, the inductance of the conductor will change greatly (for example, when testing liquid metal sealed in a silicon tube, stretching 10% will result in an increase of about 24nH). At this time, if the capacitance value in the coil element remains unchanged, the resonant frequency of the coil element will change with the change of the conductor inductance, thereby affecting the coil performance.
[0045] In view of this, the present disclosure proposes a coil assembly including a stretchable RF receiving coil element. The capacitance value in the stretchable RF receiving coil element is adjusted by setting a variable capacitor and a tuning controller in the coil assembly, thereby adjusting the resonant state of the stretchable RF receiving coil element. Regardless of whether the coil is stretched or not, the capacitance value and the resonant frequency in the coil assembly according to an embodiment of the present disclosure can be automatically tuned to the desired value, so that the coil performance remains stable.
[0046] According to a first aspect of the present disclosure, a coil assembly 10 is provided. The coil assembly 10 includes at least one stretchable RF receiving coil element 100 and a tuning controller 200. Each of the at least one stretchable RF receiving coil element 100 includes a variable capacitor 102, and the variable capacitor 102 is used to adjust the resonant frequency of the corresponding stretchable RF receiving coil element. The tuning controller 200 is at least configured to adjust the capacitance value of the variable capacitor 102 of each of the at least one stretchable RF receiving coil element 100 so that the resonant frequency of the at least one stretchable RF receiving coil element 100 is within a preset range.
[0047] Figure 1 A schematic diagram of a coil assembly according to an embodiment of the present disclosure is shown.
[0048] exist Figure 1 In the illustrated embodiment, the coil assembly 10 includes a stretchable RF receiving coil element 100. The stretchable RF receiving coil element 100 includes a capacitor circuit composed of a plurality of capacitors. The capacitor circuit includes a first capacitor 106 and a second capacitor 108 connected in series. Figure 1 The first capacitor 106, which is shown as two in number, can be a fixed value capacitor, which is used to make the stretchable RF receiving coil element resonate at the desired magnetic resonance frequency. The second capacitor 108 can be a matching capacitor, which is used to adjust the matching of the stretchable RF receiving coil element 100 so that the stretchable RF receiving coil element 100 can receive the magnetic resonance signal with the maximum amplitude, thereby better realizing the signal transmission. The stretchable RF receiving coil element 100 also includes a low noise amplifier (LNA) or a low noise converter (LNC) 110, which is used to low-noise amplify the magnetic resonance signal received by the stretchable RF receiving coil element 100 and transmit the amplified signal to the magnetic resonance system 30 for analog-to-digital conversion and digital reconstruction.
[0049] like Figure 1As shown by the black double arrows in FIG. 1 , the stretchable conductor 112 connecting the capacitors in the capacitor circuit can be stretched in all directions. When the stretchable conductor 112 is in a stretched state, its inductance increases. At this time, if the capacitance value of each capacitor in the capacitor circuit remains unchanged, the resonant frequency of the stretchable RF receiving coil element 100 will change with the change of the conductor inductance, thereby affecting the performance of the coil.
[0050] To solve the above problems, the coil component 10 according to an embodiment of the present disclosure includes a variable capacitor 102 connected in series with a first capacitor 106 and a second capacitor 108, and a tuning controller 200. In some embodiments, the variable capacitor 102 may be a voltage-controlled capacitor. When the stretchable conductor 112 is in a stretched state, the tuning controller 200 is configured to adjust the capacitance value of the variable capacitor 102 of the stretchable RF receiving coil element 100, so that the capacitance value of the stretchable RF receiving coil element 100 in the stretched state is adjusted, so that the resonant frequency of the stretchable RF receiving coil element 100 can be within a preset range, thereby keeping the coil performance stable.
[0051] In some embodiments, the tuning controller 200 is further configured to transmit at least one first signal 122, wherein the at least one first signal 122 is a signal having a magnetic resonance frequency, and the at least one stretchable RF receiving coil element 100 further comprises: a directional coupler 104, wherein the directional coupler 104 is connected to the tuning controller 200, and is used to transmit the at least one first signal 122 transmitted by the tuning controller 200 to the at least one stretchable RF receiving coil element 100, and transmit at least one second signal 124 returned by the at least one stretchable RF receiving coil element 100 to the tuning controller 200, wherein the at least one second signal 124 is a signal returned after the at least one first signal 122 passes through a corresponding one of the at least one stretchable RF receiving coil elements 100.
[0052] Continue to refer Figure 1 In the illustrated embodiment, the tuning controller 200 is further configured to transmit a first signal 122. In some embodiments, the first signal 122 is, for example, a test signal. The test signal can be generated by a small signal generator disposed in the tuning controller. The signal generator can be a direct digital frequency synthesizer (DDS) or a phase-locked frequency synthesizer (PLL), or a crystal oscillator with an analog output, to provide a test signal that can operate at a magnetic resonance frequency.
[0053] The tuning controller 200 is also configured to receive the second signal 124. Figure 1In the illustrated embodiment, the second signal 124 is a signal returned by the first signal 122 after passing through the stretchable RF receiving coil element 100. By detecting the second signal 124 returned after passing through the stretchable RF receiving coil element 100, the tuning state of the stretchable RF receiving coil element 100 can be obtained.
[0054] The second signal 124 can be detected, for example, by an analog-to-digital converter (ADC) or a power detector. In some embodiments, in order to make the tuning more accurate, the transmitting component and the receiving component of the stretchable RF receiving coil element 100 can be calibrated during the manufacturing process, and the calibration data can be stored inside the tuning controller. Calibrating the parameters of the stretchable RF receiving coil element itself and storing the calibration data inside the tuning controller can circumvent its own parameters when adjusting the stretchable RF receiving coil element, thereby making the tuning of the stretchable RF receiving coil element more accurate. In some embodiments, the tuning controller 200 is also configured to be communicatively connected to the magnetic resonance system 30 via a serial peripheral interface (SPI) or an I2C protocol.
[0055] Continue to refer Figure 1 In the illustrated embodiment, the stretchable RF receiving coil element 100 further includes: a directional coupler 104, the directional coupler 104 being connected to the tuning controller 200 and configured to transmit a first signal 122 transmitted by the tuning controller 200 to the stretchable RF receiving coil element 100, and transmit a second signal 124 returned by the stretchable RF receiving coil element 100 to the tuning controller 200, so as to achieve signal transmission between the stretchable RF receiving coil element 100 and the tuning controller 200. The directional coupler 104 may be implemented by a printed circuit board or lumped elements such as capacitors and inductors.
[0056] In some embodiments, the tuning controller 200 is configured to determine whether to adjust the capacitance value of the at least one variable capacitor 102 according to whether the at least one second signal 124 is within a threshold range.
[0057] The received second signal 124 is compared with a preset threshold range. If the second signal 124 is not within the preset threshold range, it is determined to adjust the capacitance value of the variable capacitor 102. The tuning controller 200 is further configured to adjust the voltage applied across the variable capacitor 102 (e.g., a voltage-controlled capacitor) to adjust the capacitance value of the variable capacitor 102 until the returned second signal is determined to reach the expected value. If the second signal 124 is within the preset threshold range, it is determined not to adjust the capacitance value of the variable capacitor 102.
[0058] In some embodiments, if the resonant frequency of the stretchable RF receiving coil element 100 is not much different from a preset threshold range, a fixed capacitor may be connected in parallel to the variable capacitor 102 to achieve more precise adjustment.
[0059] In some embodiments, in order to save power resources and avoid interference with magnetic resonance images, the tuning controller 200 may be further configured to be set to a shutdown state or a sleep state after completing tuning of the at least one stretchable RF receiving coil element.
[0060] Figure 2 A schematic diagram of a coil assembly according to an embodiment of the present disclosure is shown.
[0061] exist Figure 2 In the illustrated embodiment, the coil assembly 10 includes a plurality of stretchable RF receiving coil elements 100. The plurality of stretchable RF receiving coil elements each include a corresponding variable capacitor 102a, 102b ... 102n, and the variable capacitor 102a, 102b ... 102n is used to adjust the resonant frequency of the corresponding stretchable RF receiving coil element. The tuning controller 200 is configured to adjust the capacitance value of the variable capacitor 102a, 102b ... 102n of each of the plurality of stretchable RF receiving coil elements so that the resonant frequency of each of the plurality of stretchable RF receiving coil elements is within a preset range.
[0062] Continue to refer Figure 2 The tuning controller 200 is further configured to transmit a first signal 122 to each of the plurality of stretchable RF receiving coil elements 100. The first signal 122 transmitted by the tuning controller 200 to each stretchable RF receiving coil element 100 may be a test signal having a magnetic resonance frequency, and the plurality of first signals 122 may be the same or different from each other, and no limitation is made here.
[0063] exist Figure 2 In the illustrated embodiment, each of the plurality of stretchable RF receiving coil elements 100 further includes: a directional coupler 104a, 104b ... 104n, the directional coupler 104a, 104b ... 104n is connected to the tuning controller 200, and is used to transmit a plurality of first signals transmitted by the tuning controller 200 to each corresponding stretchable RF receiving coil element in the plurality of stretchable RF receiving coil elements 100, and transmit a second signal returned by each stretchable RF receiving coil element in the plurality of stretchable RF receiving coil elements 100 to the tuning controller 200. Figure 1 Similar to the embodiment shown in , the second signal is a signal returned after the first signal passes through the corresponding stretchable RF receiving coil element 100 .
[0064] exist Figure 2 In the illustrated embodiment, the tuning controller 200 is further configured to compare each of the received multiple second signals with a preset threshold range. If the second signal is not within the preset threshold range, it is determined to adjust the capacitance value of the variable capacitor corresponding to the second signal. In this case, the tuning controller is also configured to adjust the voltage applied to the variable capacitor (e.g., voltage-controlled capacitor) corresponding to the second signal, thereby adjusting the capacitance value of the variable capacitor corresponding to the second signal. If the second signal is within the preset threshold range, it is determined not to adjust the capacitance value of the variable capacitor corresponding to the second signal.
[0065] It should be understood that Figure 2 In the illustrated embodiment, the tuning controller 200 can be adjusted for each of the multiple stretchable RF receiving coil elements 100. The tuning controller 200 can control the voltage value across the variable capacitor in any stretchable RF receiving coil element without being affected by other stretchable RF receiving coil elements. By using the tuning controller 200 to control at least one stretchable RF receiving coil element 100, the coil assembly according to the present disclosure can maximize the utilization of the tuning components and avoid redundancy.
[0066] In addition, the coil assembly according to the present disclosure can simplify the tuning process during the production process. Conventional coil assemblies usually require tuning of each coil when the product leaves the factory, while the stretchable RF receiving coil element in the coil assembly according to the present disclosure can be tuned by simply adjusting the voltage of the variable capacitor when in use, simplifying the factory tuning steps. Compared with the traditional tuning process that needs to be performed on the coil element, the stretchable RF receiving coil element in the coil assembly according to the present disclosure can also achieve remote tuning.
[0067] Figure 3 A schematic diagram of a coil assembly according to another embodiment of the present disclosure is shown.
[0068] and Figure 1 Similar to the illustrated embodiment, the coil assembly 10 includes a stretchable RF receiving coil element 100 . The stretchable RF receiving coil element 100 includes a capacitor circuit composed of a plurality of capacitors and a low noise amplifier (LNA) or a low noise converter (LNC) 110 .
[0069] and Figure 1 The embodiment shown differs in that Figure 3In the illustrated embodiment, the first signal 122 (e.g., a test signal) is not transmitted to the stretchable RF receiving coil element 100 by the tunable controller 200, but is transmitted to the stretchable RF receiving coil element 100 by other devices of the magnetic resonance imaging system. The second signal 124 returned after passing through the stretchable RF receiving coil element 100 may also be received by other devices of the magnetic resonance imaging system instead of being received by the tunable controller 200. Figure 3 In the illustrated embodiment, the directional coupler 104 may not be included in the coil assembly 10 .
[0070] In the magnetic resonance imaging system, a body coil 40 and a measurement and reconstruction system 50 are included. The body coil is usually a radio frequency coil arranged inside the gradient coil, and is used to generate a high-frequency magnetic field and apply the high-frequency magnetic field to the object under test in a static magnetic field. Since the body coil has a large FOV (field of view) when the transmission signal is uniform, once the local coil of the stretchable radio frequency receiving coil element 100 is within the FOV of the body coil, the local coil can be coupled with the body coil. Based on this, in Figure 3 In the illustrated embodiment, the body coil 40 is used to provide a first signal, which may be, for example, a test signal. In addition, a measurement reconstruction system 50 in a magnetic resonance imaging system may be used to receive a second signal from the stretchable RF receiving coil element. The amplitude of the first signal may be set to be lower than a signal amplitude capable of activating the passive detuning of the stretchable RF receiving coil 100. Thus, when the body coil transmits a first signal, such as a radio frequency, the passive detuning function of the stretchable RF receiving coil is not activated and is placed in a detuned state. In this case, the stretchable RF receiving coil element may be tuned after each stretchable RF receiving coil element 100 in the local coil is set to a receiving state.
[0071] In some embodiments, the tuning controller 200 is in communication with the measurement reconstruction system 50. In some embodiments, the measurement reconstruction system 50 may send the second signal to the tuning controller 200 and the tuning controller 200 may determine whether to adjust the capacitance value of the variable capacitor 102 based on whether the second signal is within a threshold range. In some embodiments, the measurement reconstruction system 50 may also determine whether to adjust the capacitance value of the variable capacitor 102 based on whether the second signal is within a threshold range, and send a corresponding instruction (e.g., a control signal) to the tuning controller 200. If the second signal is not within a preset threshold range, the tuning controller is further configured to adjust the voltage applied across the variable capacitor 102 (e.g., a voltage-controlled capacitor) to adjust the capacitance value of the variable capacitor 102 until the returned second signal is determined to reach an expected value. If the second signal 124 is within a preset threshold range, it is determined that the capacitance value of the variable capacitor 102 is not adjusted.
[0072] and Figure 2 Similar to the embodiment shown in Figure 3 The coil assembly 10 of the embodiment may also include a plurality of stretchable RF receiving coil elements 100. Figure 2 The difference from the embodiment shown in is that each of the plurality of stretchable RF receiving coil elements 100 receives a first signal from the body coil 40. The measurement reconstruction system 50 may receive a returned second signal from each corresponding stretchable RF receiving coil element. The measurement reconstruction system 50 may send the second signal to the tuning controller 200, and the tuning controller 200 may determine whether to adjust the capacitance value of the corresponding variable capacitor 102 according to whether the second signal is within a threshold range. The measurement reconstruction system 50 may also determine whether to adjust the capacitance value of the corresponding variable capacitor 102 according to whether the second signal is within a threshold range, and send a corresponding instruction to the tuning controller 200.
[0073] Figure 4 2 shows a functional block diagram of a tuning controller 200, which can be applied to Figures 1 to 3 In the embodiment shown.
[0074] According to some embodiments of the present disclosure, the tuning controller 200 may include a second signal conversion module 310 , a control module (eg, a programmable logic module) 320 , a test signal generation module (digital synthesis module) 330 , and a control voltage signal generation module 340 .
[0075] The second signal conversion module 310 is configured to convert the received second signal 124 into a signal that can be transmitted by a digital line. The second signal conversion module 310 can be, for example, an analog-to-digital converter (ADC) or a power detector, which is used to convert the received analog signal so that the converted signal can be transmitted through a digital line.
[0076] The control module (e.g., programmable logic module) 320 is configured to generate various control instructions, such as an instruction on whether to generate a test signal, an instruction on whether to adjust the capacitance of a variable capacitor, etc. The control module 320 may be, for example, a field programmable gate array (FPGA) or a CPLD, which may be communicatively connected to the system to calculate a digital signal or a DC signal and generate corresponding instructions.
[0077] The test signal generating module 330 is configured to generate a first signal. The test signal generating module 330 may be, for example, a DDS signal generator or a phase-locked frequency synthesizer (PLL) for generating a radio frequency signal as a test signal for measuring the resonant frequency of the coil assembly based on an instruction.
[0078] The control voltage signal generating module 340 is configured to generate a signal for controlling the voltage of the variable capacitor. The control voltage signal generating module 340 may be, for example, a digital analog converter (DAC) for providing a controllable DC voltage for the variable capacitor.
[0079] In some embodiments, after the second signal 124 is transmitted to the tuning controller 200, the second signal 124, such as a high-frequency signal, can be converted into a DC signal for characterization via the second signal conversion module 310. Afterwards, the converted second signal 124 is calculated in the programmable logic module 320, and based on the comparison between the calculation result and the preset threshold range, it is determined whether to issue an instruction to adjust the voltage of the variable capacitor. The control module 320 can also be connected to the magnetic resonance imaging system via a communication interface such as I2C or SPI.
[0080] In some embodiments, for example Figure 1 or Figure 2 In the illustrated embodiment, the control module 320 in the tuning controller 200 may be configured to send an instruction to the test signal generation module 330, and the test signal generation module 330 generates the first signal 122 according to the instruction. In some embodiments, for example Figure 4 As indicated by the dashed arrow in Figure 3 In the illustrated embodiment, the first signal 122 may also be directly generated by the magnetic resonance imaging system, for example, generated by a body coil and sent to the stretchable RF receiving coil element. Figure 3 In the illustrated embodiment, the test signal generating module 330 is optional.
[0081] In some embodiments, the control module 320 in the tuning controller 200 may also be configured to send instructions to the control voltage signal generation module 340 to generate the control voltage 126 for controlling the voltage across the variable capacitor 102 .
[0082] According to a second aspect of the present disclosure, a magnetic resonance imaging system is provided, comprising a coil assembly according to any one of the above embodiments.
[0083] It should be understood that the features and advantages described above for the coil assembly are also applicable to the magnetic resonance imaging system. For the sake of brevity, some features and advantages are not described in detail here.
[0084] According to a third aspect of the present disclosure, a tuning method 500 for a magnetic resonance imaging system according to the second aspect is provided. The method 500 comprises:
[0085] Step S510, sending at least one first signal to at least one stretchable radio frequency receiving coil element;
[0086] Step S520: receiving at least one second signal from the at least one stretchable RF receiving coil element, wherein the at least one second signal is a signal returned after the at least one first signal passes through a corresponding one of the at least one stretchable RF receiving coil element; and
[0087] Step S530: Use a tuning controller to adjust the capacitance value of the variable capacitor of at least one stretchable RF receiving coil element according to the second signal to adjust the resonant frequency of the at least one stretchable RF receiving coil element until the resonant frequency of the at least one stretchable RF receiving coil element is adjusted to within a preset range.
[0088] In some embodiments, for example, in an embodiment where the tuning controller includes a test signal generation module 330 and a second signal conversion module 310, at least one first signal may be sent by the tuning controller and at least one second signal may be received by the tuning controller from at least one stretchable RF receiving coil element. Figure 6 Step S510, sending at least one first signal to at least one stretchable radio frequency receiving coil element, comprising:
[0089] Step S611, placing the at least one stretchable radio frequency receiving coil element on the object to be measured and placing the object to be measured in a scanning position; and
[0090] Step S612: Use the tuning controller to send at least one first signal to the at least one stretchable RF receiving coil element.
[0091] In some embodiments, in step S611, after the subject to be tested is placed on the bed, the at least one stretchable RF receiving coil element according to the embodiment of the present disclosure is placed at the part to be scanned of the subject to be tested. After the stretchable RF receiving coil element at the part to be scanned of the subject to be tested has been fixed in place and the subject to be tested reaches the scanning position, the step proceeds to S612, using the tuning controller to send at least one first signal to the at least one stretchable RF receiving coil element.
[0092] In some embodiments, the step continues to step S620, using the tuning controller to receive the at least one second signal from the at least one stretchable RF receiving coil element, wherein the at least one second signal is a signal returned after the at least one first signal passes through a corresponding one of the at least one stretchable RF receiving coil elements.
[0093] In some embodiments, the steps proceed to S530, wherein step S530, adjusting the capacitance value of the variable capacitor of each of the at least one stretchable RF receiving coil element using the tuning controller according to the second signal to adjust the resonant frequency of the at least one stretchable RF receiving coil element until the resonant frequency of the at least one stretchable RF receiving coil element is adjusted to within a preset range, comprises:
[0094] Step S631: Use the tuning controller to determine whether to adjust the capacitance value of the variable capacitor of each of the at least one stretchable RF receiving coil elements according to the at least one second signal.
[0095] After receiving the second signal, the tuning controller may compare the obtained second signal with a preset threshold range.
[0096] If the second signal is within the preset threshold range, the process proceeds to step S640 and the tuning process ends.
[0097] If the second signal is not within the preset threshold range, the process proceeds to step S632, and the capacitance value of the variable capacitor of each of the at least one stretchable RF receiving coil element is adjusted using the tuning controller to adjust the resonant frequency of the at least one stretchable RF receiving coil element. After the at least one stretchable RF receiving coil element completes the adjustment of the resonant frequency, the process returns to step S612, and the at least one first signal is sent to the at least one stretchable RF receiving coil element using the tuning controller. The tuning process ends until the resonant frequency of the at least one stretchable RF receiving coil element is adjusted to within the preset range, that is, when the returned second signal is within the preset threshold range.
[0098] At this time, the tuning controller 200 may be set to an off state or a sleep state.
[0099] In other embodiments, for example, in an embodiment where the tuning controller does not include the test signal generation module 330 and the second signal conversion module 310, the first signal may be transmitted by the body coil of the magnetic resonance imaging system, and the measurement and reconstruction system may receive the second signal returned through the stretchable RF receiving coil element, process the second signal when necessary, and issue an instruction on whether to adjust the variable capacitance of the stretchable RF receiving coil element based on the second signal. In this case, the method 500 may include: using the tuning controller to receive the second signal from the measurement and reconstruction system or the control instruction issued by the measurement and reconstruction system indicating whether to adjust the variable capacitance of the stretchable RF receiving coil element, and adjusting the capacitance value of the variable capacitor of the at least one stretchable RF receiving coil element according to the received second signal or the control instruction until the resonant frequency of the at least one stretchable RF receiving coil element is adjusted to a preset range.
[0100] Although the embodiments or examples of the present disclosure have been described with reference to the accompanying drawings, it should be understood that the above-mentioned methods, systems and devices are merely exemplary embodiments or examples, and the scope of the present invention is not limited by these embodiments or examples, but only by the claims after authorization and their equivalent scope. Various elements in the embodiments or examples can be omitted or replaced by their equivalent elements. In addition, each step can be performed in an order different from that described in the present disclosure. Further, the various elements in the embodiments or examples can be combined in various ways. It is important that with the evolution of technology, many elements described herein can be replaced by equivalent elements that appear after the present disclosure.
Claims
1. A coil assembly, comprising: at least one stretchable RF receive coil element, each of the at least one stretchable RF receive coil element comprising a variable capacitor, the variable capacitor being used to adjust a resonant frequency of the corresponding stretchable RF receive coil element; as well as A tuning controller is configured to adjust the capacitance value of the variable capacitor of each of the at least one stretchable RF receiving coil element so that the resonant frequency of the at least one stretchable RF receiving coil element is within a preset range.
2. The coil assembly according to claim 1, wherein: The tuning controller is further configured to transmit at least one first signal, each of which is a signal having a magnetic resonance frequency. Each of the at least one stretchable RF receiving coil element further comprises a directional coupler, which is connected to the tuning controller and is used to transmit at least one first signal transmitted by the tuning controller to the at least one stretchable RF receiving coil element, and transmit at least one second signal returned by the at least one stretchable RF receiving coil element to the tuning controller. The at least one second signal is a signal returned after the at least one first signal passes through a corresponding one of the at least one stretchable RF receiving coil elements.
3. The coil assembly according to claim 2, wherein: The tuning controller is configured to determine whether to adjust a capacitance value of the at least one variable capacitor according to whether the at least one second signal is within a threshold range.
4. The coil assembly according to claim 1, wherein: The coil assembly is used in a magnetic resonance imaging system, wherein the magnetic resonance system comprises a body coil and a measurement and reconstruction system. The body coil is configured to transmit at least one first signal to the at least one stretchable radio frequency receive coil element, The measurement reconstruction system is configured to receive at least one second signal from the at least one stretchable RF receiving coil element, wherein the at least one second signal is a signal returned after the at least one first signal passes through a corresponding one of the at least one stretchable RF receiving coil element. The tuning controller is configured to be communicatively connected with the measurement reconstruction system to receive the at least one second signal or to receive a control signal issued by the measurement reconstruction system to determine whether to adjust the capacitance value of the at least one variable capacitor.
5. The coil assembly according to claim 4, wherein: The amplitude of the at least one first signal is selected to be lower than a signal amplitude capable of activating a passive detuning of the at least one stretchable RF receive coil.
6. The coil assembly according to any one of claims 1 to 5, wherein: The variable capacitor is a voltage-controlled capacitor, and the tuning controller is configured to adjust a control voltage applied to the voltage-controlled capacitor.
7. The coil assembly according to any one of claims 1 to 5, wherein: The variable capacitor is connected in parallel with a fixed capacitor.
8. The coil assembly according to claim 1, wherein: The tuning controller includes a test signal generating module, a second signal conversion module, a control module and a control voltage signal generating module, wherein: The test signal generating module is at least configured to generate the at least one first signal; The second signal conversion module is at least configured to receive the at least one second signal; The control module is at least configured to communicate with the second signal conversion module, the test signal generation module and the control voltage signal generation module and generate a control instruction; and The control voltage signal generating module is at least configured to generate a control signal for controlling the voltage of the variable capacitor.
9. A magnetic resonance imaging system, comprising the coil assembly according to any one of claims 1-8.
10. A tuning method for a magnetic resonance imaging system according to claim 9, comprising: transmitting at least one first signal to at least one stretchable radio frequency receive coil element; receiving at least one second signal from the at least one stretchable RF receiving coil element, wherein the at least one second signal is a signal returned after the at least one first signal passes through a corresponding one of the at least one stretchable RF receiving coil element; as well as According to the second signal, a tuning controller is used to adjust the capacitance value of the variable capacitor of the at least one stretchable RF receiving coil element to adjust the resonant frequency of the at least one stretchable RF receiving coil element until the resonant frequency of the at least one stretchable RF receiving coil element is adjusted to a preset range.
11. The tuning method according to claim 10, comprising: After the at least one stretchable RF receiving coil element is placed on the object to be measured and the object to be measured is in a scanning position, using the tuning controller to send the at least one first signal to the at least one stretchable RF receiving coil element; receiving the at least one second signal from the at least one stretchable RF receive coil element using the tuning controller; as well as The tuning controller is used to determine whether to adjust a capacitance value of a variable capacitor of each of the at least one stretchable RF receive coil elements based on the at least one second signal.
12. The tuning method according to claim 10, wherein: The coil assembly is used in a magnetic resonance imaging system, the magnetic resonance system comprising a body coil and a measurement and reconstruction system, the body coil being configured to transmit the at least one first signal to the at least one stretchable radio frequency receiving coil element, the measurement and reconstruction system being configured to receive the at least one second signal from the at least one stretchable radio frequency receiving coil element, The tuning method comprises: The tuning controller is used to receive the at least one second signal from the measurement reconstruction system, or to receive a control signal issued by the measurement reconstruction system based on the at least one second signal, indicating whether to adjust the capacitance value of the at least one variable capacitor.