Frequency detection device of radio frequency coil and magnetic resonance imaging system
Through the contactless frequency detection device, the transmitting and receiving coils are used to perform radio frequency coil frequency detection, which solves the problem of loss introduced by the frequency detection circuit and improves the signal-to-noise ratio and detection quality.
Patent Information
- Application Number
- CN202421989282.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-15
- Publication Date
- 2025-06-24
- Estimated Expiration
- 2034-08-15
AI Technical Summary
In the prior art, the frequency detection circuit of the radio frequency coil introduces losses, resulting in a decrease in the signal-to-noise ratio.
Using a contactless frequency detection device, the detection signal is sent through the transmitting coil, causing the radio frequency coil to generate an induction signal, and the receiving coil is decoupled to determine the current frequency of the radio frequency coil.
The loss of frequency detection to the radio frequency coil is reduced, the signal-to-noise ratio is improved, and the quality of frequency detection is improved.
Smart Images
Figure CN223022235U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of magnetic resonance imaging technology, and particularly to a frequency detection device for a radio frequency coil and a magnetic resonance imaging system. Background Art
[0002] A radio frequency coil is a device for receiving and transmitting radio frequency signals. The frequency of the radio frequency coil will shift due to changes in the load. In order to keep the resonant frequency of the radio frequency coil stable at the system frequency, it is necessary to tune the resonant frequency of the coil. Before tuning, it is necessary to detect the frequency shift. In the prior art, in order to detect the frequency of the radio frequency coil, a frequency detection circuit is usually connected behind the coil. The frequency detection circuit mainly includes a switch and a coupler.
[0003] However, the introduction of the frequency detection circuit often brings more losses, resulting in a decrease in the signal-to-noise ratio of the radio frequency coil. Summary of the Utility Model
[0004] In this embodiment, a frequency detection device for a radio frequency coil and a magnetic resonance imaging system are provided to solve the problem in the related art that the introduction of frequency detection brings more losses, resulting in a decrease in the signal-to-noise ratio of the radio frequency coil.
[0005] In a first aspect, in this embodiment, a frequency detection device for a radio frequency coil is provided. The device is configured to be spaced apart from the radio frequency coil to be detected by a preset distance and arranged opposite to each other during detection. The device includes: a transmitting coil and a receiving coil;
[0006] The transmitting coil is configured to send a detection signal to the radio frequency coil, so that the radio frequency coil generates an induced signal under the action of the detection signal;
[0007] The receiving coil is arranged in a decoupled manner with the transmitting coil and is configured to determine the current frequency of the radio frequency coil based on the induced signal.
[0008] In this way, the non-contact frequency detection of the radio frequency coil is performed by the decoupled detection coil, avoiding additional losses to the radio frequency coil, helping to improve the signal-to-noise ratio of the radio frequency coil, and also improving the quality of frequency detection.
[0009] In some of these embodiments, the transmitting coil includes a first coil unit; the receiving coil includes a second coil unit;
[0010] The decoupled arrangement is that the wires of the first coil unit and the second coil unit overlap each other.
[0011] In this way, by simply adjusting the relative overlapping area of the first coil unit and the second coil unit, the optimal decoupling can be achieved without the assistance of other decoupling means, simplifying the design of the frequency detection device.
[0012] In some of these embodiments, the transmitting coil further includes: a first configuration circuit;
[0013] The first configuration circuit is connected to the first coil unit and is used to control the first coil unit to transmit the detection signal.
[0014] In this way, through the first configuration circuit, the first coil unit is efficiently and accurately controlled to achieve high-quality transmission of the detection signal.
[0015] In some of these embodiments, the receiving coil further includes: a second configuration circuit;
[0016] The second coil unit is connected to the second configuration circuit and is used to receive the induction signal under the control of the second configuration circuit;
[0017] The second configuration circuit is used to determine the current frequency of the radio frequency coil based on the induction signal.
[0018] In this way, through the second configuration circuit, the second coil unit is efficiently and accurately controlled to achieve high-quality transmission of the detection signal.
[0019] In some of these embodiments, the first coil unit and the second coil unit are arranged in the same plane.
[0020] In this way, two coils overlapping each other on the same plane contribute to the calculation of the overlapping area, thereby improving the signal detection accuracy.
[0021] In some of these embodiments, the shape of the first coil unit is annular.
[0022] In this way, the magnetic field in the coil is concentrated and enhanced, and by setting the number of layers and the spacing of the circular coils, the coupling effect and the magnetic field strength are balanced.
[0023] In some of these embodiments, the second coil unit has the same shape as the first coil unit.
[0024] In this way, the structure of the frequency detection device is simplified and the design efficiency is improved.
[0025] In a second aspect, a magnetic resonance imaging system is provided in this embodiment, including: a coil system;
[0026] The coil system includes: a radio frequency coil and the frequency detection device of the radio frequency coil in the first aspect above.
[0027] In this way, by means of a radio frequency coil and a frequency detection device that are not in direct contact, the current frequency of the radio frequency coil can be efficiently measured, avoiding the problem that a frequency detection circuit built into the radio frequency coil introduces large losses, thereby reducing the signal-to-noise ratio of the radio frequency coil, achieving low-loss detection of the frequency of the radio frequency coil, and improving the signal-to-noise ratio of the radio frequency coil.
[0028] In some of these embodiments, the radio frequency coil includes: a third coil unit and a tuning circuit connected to the third coil unit;
[0029] The third coil unit is configured to collect a collection signal from a measured object or to generate an induction signal under the action of a detection signal;
[0030] The tuning circuit is configured to perform tuning processing on the collection signal based on the current frequency to obtain an initial imaging signal.
[0031] In this way, the adjustment of the current frequency is achieved through the tuning circuit, so that the resonant frequency of the radio frequency coil is stabilized at the system frequency.
[0032] In some of these embodiments, the radio frequency coil further includes: a preamplifier;
[0033] The preamplifier is connected to the tuning circuit and is configured to amplify the initial imaging signal output by the tuning circuit.
[0034] In this way, the tuned collection signal is amplified for subsequent processing by other devices.
[0035] Compared with the related art, in the frequency detection device of the radio frequency coil provided in this embodiment, during detection, it is placed on the opposite side of the radio frequency coil to be detected. The device includes: a transmitting coil and a receiving coil; the transmitting coil is configured to send a detection signal to the radio frequency coil so that the radio frequency coil generates an induction signal under the action of the detection signal; the receiving coil is decoupled from the transmitting coil and is configured to determine the current frequency of the radio frequency coil based on the induction signal, solving the problem that a frequency detection circuit built into the radio frequency coil introduces large losses, achieving low-loss detection of the frequency of the radio frequency coil, and improving the signal-to-noise ratio of the radio frequency coil.
[0036] Details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more comprehensible. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments and descriptions thereof of the present application are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings:
[0038] Figure 1 Structural schematic diagram of an existing device for measuring the frequency of a radio frequency coil;
[0039] Figure 2 Block diagram of the frequency detection device of the radio frequency coil in an embodiment;
[0040] Figure 3 Structural schematic diagram of the frequency detection device of the radio frequency coil in a preferred embodiment;
[0041] Figure 4 Structural schematic diagram of the radio frequency coil in an embodiment.
[0042] Reference numerals: 100, frequency detection device of the radio frequency coil; 110, transmitting coil; 111, first coil unit; 112, first configuration circuit; 120, receiving coil; 121, second coil unit; 122, second configuration circuit; 200, radio frequency coil; 210, third coil unit; 220, tuning circuit; 230, preamplifier. Detailed implementation manners
[0043] For a clearer understanding of the purpose, technical solutions and advantages of the present application, the present application will be described and explained below with reference to the accompanying drawings and embodiments.
[0044] Unless otherwise defined, the technical terms or scientific terms involved in the present application shall have the general meanings understood by those with ordinary skills in the technical field to which the present application belongs. In the present application, words such as "a", "one", "a kind of", "the", "these" and the like do not indicate a limitation in quantity, and they can be singular or plural. The terms "including", "comprising", "having" and any variants thereof involved in the present application are intended to cover non-exclusive inclusion; for example, a process, method, system, product or device including a series of steps or modules (units) is not limited to the listed steps or modules (units), but may include unlisted steps or modules (units), or may include other steps or modules (units) inherent in these processes, methods, products or devices. The terms "connected", "coupled" and the like involved in the present application do not limit to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "plurality" involved in the present application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" may represent: A exists alone, A and B exist simultaneously, and B exists alone. Usually, the character " / " indicates that the objects before and after are in an "or" relationship. The terms "first", "second", "third" and the like involved in the present application are only used to distinguish similar objects and do not represent a specific order for the objects.
[0045] The frequency of the RF coil will shift due to changes in the load. To stabilize the resonant frequency of the RF coil at the system frequency, it is necessary to tune the coil resonant frequency. Before tuning, it is necessary to detect the frequency shift. In the prior art, to detect the frequency of the RF coil, refer to Figure 1 , it is necessary to connect a frequency detection circuit behind the coil. The frequency detection circuit usually includes a switch and a coupler. However, the introduction of the frequency detection circuit often brings more losses, resulting in a decrease in the signal-to-noise ratio of the RF coil. In the embodiments of the present application, a coupling detection method is adopted, which does not require adding a detection circuit at the rear end of the coil, reduces the losses brought by the detection circuit, and improves the signal-to-noise ratio.
[0046] In this embodiment, a frequency detection device 100 for an RF coil is provided. Figure 2 It is a structural block diagram of the frequency detection device 100 for the RF coil in this embodiment. As Figure 2 shown, when detecting, the frequency detection device 100 of the RF coil 200 (hereinafter referred to as the frequency detection device 100) is spaced apart from the RF coil 200 to be detected by a preset distance and is disposed opposite. The frequency detection device 100 includes: a transmitting coil 110 and a receiving coil 120.
[0047] The transmitting coil 110 is configured to send a detection signal to the RF coil 200, so that the RF coil 200 generates an induced signal under the action of the detection signal.
[0048] The receiving coil 120 is decoupled from the transmitting coil 110 and is configured to determine the current frequency of the RF coil 200 based on the induced signal.
[0049] Specifically, when in use, the frequency detection device 100 in this embodiment can be placed non-contact directly above the RF coil 200 through a mechanical transmission device, so that the detection signal emitted by the detection device can reach the RF coil 200, and the induced signal generated by the RF coil 200 can reach the receiving coil 120. When the receiving coil 120 detects the induced signal, the frequency point with the strongest detected signal is the center frequency of the RF coil 200, and then this strongest frequency point is determined as the current frequency.
[0050] When the transmitting coil 110 and the receiving coil 120 without decoupling setting act on the radio frequency coil 200 to be detected together, a large coupling effect will be generated, which will affect the measurement accuracy. To eliminate or reduce this coupling effect, the transmitting coil 110 and the receiving coil 120 are decoupled in this embodiment. The decoupling setting includes but is not limited to minimizing the coupling between them by designing the geometric shape and layout of the coils, reducing the coupling effect between the two by adjusting the size of the overlapping area between the transmitting coil 110 and the receiving coil 120, and reducing the noise or interference introduced by the coupling.
[0051] For the layout planning of the coils, the coil parts in the transmitting coil 110 and the receiving coil 120 can be overlapped, and the optimal decoupling effect can be achieved by adjusting the overlapping area between the two; or multiple coils in the transmitting coil 110 and the receiving coil 120 can be staggered, so that the magnetic fields between them cancel each other out; or by increasing the distance between the transmitting coil 110 and the receiving coil 120, reducing the magnetic field overlap between the two, and reducing the coupling effect. Among them, the geometric shape of the coil can consider using a square coil, a circular coil or a butterfly coil, etc. Due to its right-angled edge, the square coil can achieve a more compact single-layer laying, and its effective detection range is mainly concentrated in the inner area of the coil, improving the detection efficiency. In the multi-layer coil structure, the magnetic field distribution inside the circular coil is more concentrated and the magnetic induction intensity is stronger. By setting the number of layers and the distance of the circular coil, the coupling effect and the magnetic field strength are balanced; the structure of the butterfly coil is in the shape of an 8, and its two loops have opposite current flows, generating a magnetic field parallel to the coil plane. When the coils of this structure are overlapped and placed parallel to the circular coil, the magnetic fields generated by the two coils are perpendicular to each other, which is called orthogonality. At this time, the coupling between the two coils is very small and can be ignored. In this embodiment, the specific implementation structure of the decoupling setting is not limited.
[0052] In the above embodiment, the frequency detection device 100 of the radio frequency coil is placed on the opposite side of the radio frequency coil 200 to be detected. The frequency detection device 100 includes: a transmitting coil 110 and a receiving coil 120; the transmitting coil 110 is used to send a detection signal to the radio frequency coil 200 so that the radio frequency coil 200 generates an induced signal under the action of the detection signal; the receiving coil 120 is decoupled from the transmitting coil 110 and is used to determine the current frequency of the radio frequency coil 200 based on the induced signal, solving the problem that the frequency detection circuit built in the corresponding circuit of the radio frequency coil 200 will introduce large losses, realizing non-contact frequency detection, and helping to improve the signal-to-noise ratio of the radio frequency coil 200.
[0053] In some of these embodiments, see Figure 3, the transmitting coil 110 includes a first coil unit 111; the receiving coil 120 includes a second coil unit 121; the decoupling is set such that the wires of the first coil unit 111 and the second coil unit 121 overlap each other.
[0054] Specifically, when manufacturing the detection coil, by adjusting the overlapping area between the two coil wires to achieve an ideal decoupling effect. For example, taking the gain / loss parameter S21 as the design reference, when the S21 value is less than 75 dB, an ideal decoupling effect is achieved, and at this time, the interference between the transmitting coil 110 and the receiving coil 120 is minimized.
[0055] Among them, the first coil unit 111 and the second coil unit 121 can be a single-turn coil, a multi-turn coil or a multi-turn coil structure, and can be a planar coil or a three-dimensional coil. The specific structure of the corresponding coil is not limited in this embodiment.
[0056] In this embodiment, by simply adjusting the relative overlapping area of the first coil unit 111 and the second coil unit 121, the best decoupling can be achieved without the assistance of other decoupling means, simplifying the design of the frequency detection device 100.
[0057] In some of the embodiments, refer to Figure 3 , the first coil unit 111 and the second coil unit 121 are arranged on the same plane.
[0058] Specifically, the first coil unit 111 and the second coil unit 121 can adopt planar coils and overlap with each other on the same plane, which helps to calculate the overlapping area and thus improve the signal detection accuracy.
[0059] In some of the embodiments, refer to Figure 3 , the shape of the first coil unit 111 is annular.
[0060] Specifically, the first coil unit 111 is an annular coil wound by a single-turn coil or a multi-turn coil. The annular coil has good stability and reliability. Due to its compact structure, it has strong resistance to external interference. In addition, the manufacturing process of the annular coil is relatively simple and the cost is low.
[0061] In some of the embodiments, refer to Figure 3 , the second coil unit 121 has the same shape as the first coil unit 111.
[0062] Specifically, when the first coil unit 111 is a single-turn annular coil, the second coil unit 121 also adopts a single-turn annular coil structure, and their materials, dimensions and shapes are exactly the same, thus simplifying the structure of the frequency detection device 100 and improving the design efficiency.
[0063] In some of the embodiments, refer toFigure 3 , the transmitting coil 110 further includes: a first configuration circuit 112; the first configuration circuit 112 is connected to the first coil unit 111 and is used to control the first coil unit 111 to transmit a detection signal.
[0064] Specifically, the first configuration circuit 112 includes an excitation signal source for generating a detection signal for the first coil unit to transmit. The first configuration circuit 112 further includes a receiver for receiving the induction signal obtained by the first coil unit 111. At this time, the transmitting coil can be used as a receiving coil. The first configuration circuit 112 further includes a data processing unit and a display unit. The data processing unit is used to further process the detection signal or the induction signal and display the processing result on the display unit.
[0065] In some embodiments, refer to Figure 3 , the receiving coil 120 further includes: a second configuration circuit 122; the second coil unit 121 is connected to the second configuration circuit 122 and is used to receive the induction signal under the control of the second configuration circuit 122; the second configuration circuit 122 is used to determine the current frequency of the radio frequency coil 200 based on the induction signal.
[0066] Specifically, the second configuration circuit 122 includes a receiver for receiving the induction signal obtained by the second coil unit 121. The second configuration circuit 122 further includes an excitation signal source for generating a detection signal for the second coil unit to transmit. At this time, the receiving coil can be used as a transmitting coil. The second configuration circuit 122 further includes a data processing unit and a display unit. The data processing unit is used to further process the detection signal or the induction signal and display the processing result on the display unit.
[0067] In this embodiment, a magnetic resonance imaging system is provided. The magnetic resonance imaging system includes: a coil system. The coil system includes: a radio frequency coil 200 and a frequency detection device 100 for the radio frequency coil in any of the above embodiments.
[0068] Specifically, before using this magnetic resonance imaging system to perform magnetic resonance scanning on the object to be measured, the frequency detection device 100 is placed above the radio frequency coil 200. First, the radio frequency coil 200 is detected by the frequency detection device 100. The detection process mainly involves the transmitting coil 110 of the frequency detection device 100 transmitting a detection signal. The radio frequency coil 200 generates an induced signal under the action of the detection signal. The receiving coil 120 of the frequency detection device 100 receives the induced signal and determines the current frequency of the radio frequency coil 200 based on the induced signal, thereby completing the frequency detection of the radio frequency coil 200. If the detected current frequency does not meet the operating frequency of the magnetic resonance imaging system, the staff can manually activate the tuning circuit 220 of the radio frequency coil 200 to perform tuning processing on the radio frequency coil 200 so that the current frequency of the radio frequency coil 200 reaches the operating frequency. After the frequency adjustment is completed, the radio frequency coil 200 is placed above the object to be measured, and the object to be measured is scanned through the radio frequency coil 200 to obtain accurate magnetic resonance imaging data.
[0069] In this embodiment, by the method of not directly contacting the radio frequency coil 200 and the frequency detection device 100, the current frequency of the radio frequency coil 200 can be efficiently measured, avoiding the problem that the frequency detection circuit built into the radio frequency coil 200 will introduce large losses, realizing low-loss detection of the frequency of the radio frequency coil 200, and improving the signal-to-noise ratio of the radio frequency coil 200.
[0070] In some of these embodiments, refer to Figure 4 , the radio frequency coil 200 includes: a third coil unit 210 and a tuning circuit 220 connected to the third coil unit 210.
[0071] The third coil unit 210 is used to collect a collection signal from the object to be measured. Among them, the third coil unit 210 is placed on one side of the object to be measured to collect information emitted by the object to be measured; or is used to generate an induced signal under the action of the detection signal.
[0072] The tuning circuit 220 is used to receive the collection signal of the third coil unit 210 and perform tuning processing on the collection signal based on the current frequency to obtain an initial imaging signal.
[0073] Specifically, in use, the radio frequency coil 200 and the frequency detection device 100 in the coil system can be directly placed above the object to be measured. During the magnetic resonance scanning process, the current frequency of the third coil unit 210 is first measured by the frequency detection device 100. If the detected current frequency does not meet the operating frequency of the magnetic resonance imaging system, the staff can manually activate the tuning circuit 220 of the radio frequency coil 200, or after the tuning circuit 220 judges the current frequency, automatically select whether to perform tuning.
[0074] In some of these embodiments, referring to Figure 4 , the radio frequency coil 200 further includes: a preamplifier 230; the preamplifier 230 is connected to the tuning circuit 220 and is configured to amplify the initial imaging signal output by the tuning circuit 220.
[0075] Obviously, the accompanying drawings are only some examples or embodiments of the present application. For those of ordinary skill in the art, the present application can also be applied to other similar situations based on these drawings without creative efforts. Additionally, it can be understood that although the work done during this development process may be complex and time-consuming, for those of ordinary skill in the art, certain design, manufacturing, or production changes based on the technical content disclosed in the present application are only conventional technical means and should not be regarded as insufficient disclosure of the present application.
[0076] The term "embodiment" in this application means that the specific features, structures, or characteristics described in connection with the embodiment may be included in at least one embodiment of the present application. The phrase appears in various positions in the specification and does not necessarily mean the same embodiment, nor does it mean being independent or alternative to other embodiments and mutually exclusive. Those of ordinary skill in the art can clearly or implicitly understand that the embodiments described in the present application can be combined with other embodiments without conflict.
[0077] The above-described embodiments only represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limitations on the scope of patent protection. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.
Claims
1. A frequency detection device for a radio frequency coil, characterized in that: The device is used to be arranged relative to the radio frequency coil to be detected at a preset distance during detection, and the device includes: a transmitting coil and a receiving coil; The transmitting coil is used to send a detection signal to the radio frequency coil, so that the radio frequency coil generates an induction signal under the action of the detection signal; The receiving coil is decoupled from the transmitting coil and is used to determine the current frequency of the radio frequency coil based on the induction signal.
2. The frequency detection device of the radio frequency coil according to claim 1, characterized in that: The transmitting coil includes a first coil unit; the receiving coil includes a second coil unit; The decoupling is configured such that the conductive lines of the first coil unit and the second coil unit overlap each other.
3. The frequency detection device of the radio frequency coil according to claim 2, characterized in that: The transmitting coil further includes: a first configuration circuit; The first configuration circuit is connected to the first coil unit and is used to control the first coil unit to transmit the detection signal.
4. The frequency detection device of the radio frequency coil according to claim 2, characterized in that: The receiving coil further includes: a second configuration circuit; The second coil unit is connected to the second configuration circuit, and is used to receive the induction signal under the control of the second configuration circuit; The second configuration circuit is configured to determine a current frequency of the radio frequency coil based on the induction signal.
5. The frequency detection device of the radio frequency coil according to claim 2, characterized in that: The first coil unit and the second coil unit are arranged on the same plane.
6. The frequency detection device of the radio frequency coil according to claim 2, characterized in that: The first coil unit is in a ring shape.
7. The frequency detection device of the radio frequency coil according to claim 2, characterized in that: The second coil unit has the same shape as the first coil unit.
8. A magnetic resonance imaging system, characterized in that: include: Coil system; The coil system comprises: a radio frequency coil and a frequency detection device of the radio frequency coil according to any one of claims 1-7.
9. The magnetic resonance imaging system according to claim 8, characterized in that: The radio frequency coil comprises: a third coil unit and a tuning circuit connected to the third coil unit; The third coil unit is used to collect a collection signal from the object to be measured, or to generate an induction signal under the action of a detection signal; The tuning circuit is used to perform tuning processing on the acquisition signal based on the current frequency to obtain an initial imaging signal.
10. The magnetic resonance imaging system according to claim 9, characterized in that: The radio frequency coil further comprises: a preamplifier; The preamplifier is connected to the tuning circuit and is used to amplify the initial imaging signal output by the tuning circuit.