CN216696639U - Trap, radio frequency coil assembly and magnetic resonance imaging system - Google Patents

Abstract

The application relates to a wave trap, a radio frequency coil assembly and a magnetic resonance imaging system. The wave trap comprises a bracket and a shielding sleeve, and an inductance element is arranged on the bracket; the shielding sleeve is sleeved on the support, at least two capacitor assemblies are arranged on the shielding sleeve, the voltage division effect is achieved, the heating points are divided into at least two positions, and the ignition risk is reduced. At the same time, the shielding sleeve is reserved, and the advantage that the wave trap has small influence on the local B1 field is reserved.

Description

Trap, radio frequency coil assembly and magnetic resonance imaging system

Technical Field

The present application relates to the field of magnetic resonance imaging technology, and in particular, to a trap, a radio frequency coil assembly, and a magnetic resonance imaging system.

Background

In magnetic resonance imaging apparatuses, in order to obtain the best possible signal-to-noise ratio, the local coil is usually positioned as close as possible to the body of the subject or patient. For further transmission of the magnetic resonance signals from the local coil to the signal processing system, shielded coaxial cables are usually employed. The local coil is connected to a first coaxial cable that is plugged into the examination table. A further coaxial cable is connected to the connector of the examination table, which leads the magnetic resonance signals out of the examination table and onward to a signal processing system.

Due to the electric field and the magnetic field formed at the transmission or reception stage of the high-frequency pulse, a high-frequency current is induced on the wire cover (metal shield layer) of the coaxial cable. Without appropriate suppression measures, image disturbances can result and in the worst case, risks to the patient.

In order to suppress the generation of high-frequency currents, wave traps integrated in the patient bed are used. The main function of the wave trap is to suppress the burning of the patient by the large current generated by the common-mode signal on the radio frequency cable. The wave trap generates a suppression signal at the working frequency point of nuclear magnetic resonance according to the principle that resonance is generated by capacitance and inductance.

However, the conventional trap is provided with a capacitor only at one end, heat generation is excessively concentrated, and ignition is easily caused.

SUMMERY OF THE UTILITY MODEL

In view of the above, it is desirable to provide a wave trap, a radio frequency coil assembly and a magnetic resonance imaging system.

A wave trap comprising a support and a shielding sleeve, wherein:

an inductance element is arranged on the bracket;

the shielding sleeve is sleeved on the support, and at least two capacitor assemblies are arranged on the shielding sleeve.

Above-mentioned wave trap be provided with two at least capacitance assembly on the shielding sleeve, play the effect of partial pressure, and will generate heat the point and divide into two at least places, reduce the risk of striking sparks.

In one embodiment, the shielding sleeve is a cylinder.

In one embodiment, the shielding sleeve is provided with two capacitor assemblies, and the two capacitor assemblies are respectively arranged on two bottom surfaces of the shielding sleeve.

In the wave trap, the two capacitor assemblies are arranged on the bottom surface of the shielding sleeve and are not directly exposed on the surface, so that the influence on the local B1 field is reduced.

In one embodiment, the inductive element is a coil, and the coil is wound on the bracket.

In one embodiment, the bracket is provided with a spiral groove for accommodating the coil.

In one embodiment, the bracket is machined from a non-metallic material.

In one embodiment, the shielding sleeve is formed from a nonmagnetic metal working.

In one embodiment, the support is a cylinder.

A radio frequency coil assembly comprises a radio frequency coil, a cable connected with the radio frequency coil and the wave trap, wherein the wave trap is connected to the cable.

A magnetic resonance imaging system comprises the radio frequency coil assembly.

The wave trap, the radio frequency coil assembly and the magnetic resonance imaging system comprise a bracket and a shielding sleeve, wherein an inductance element is arranged on the bracket; the shielding sleeve is sleeved on the support, at least two capacitor assemblies are arranged on the shielding sleeve, the voltage division effect is achieved, the heating points are divided into at least two positions, and the ignition risk is reduced.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a wave trap according to an embodiment of the present invention.

Description of reference numerals: 10. a support; 20. a shielding sleeve; 21. a first capacitor plate; 22. a second capacitive plate.

Detailed Description

To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Embodiments of the present application are set forth in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

It will be understood that, as used herein, the terms "first," "second," and the like may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another.

Spatial relational terms, such as "under," "below," "under," "over," and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements or features described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary terms "under" and "under" can encompass both an orientation of above and below. In addition, the device may comprise additional orientations (e.g., rotated 90 degrees or other orientations) and the spatial descriptors used herein interpreted accordingly.

It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or be connected to the other element through intervening elements. Further, "connection" in the following embodiments is understood to mean "electrical connection", "communication connection", or the like, if there is a transfer of electrical signals or data between the connected objects.

As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises/comprising," "includes" or "including," or "having," and the like, specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, as used in this specification, the term "and/or" includes any and all combinations of the associated listed items.

Magnetic Resonance Imaging (MRI) is a technique for Imaging using a Magnetic Resonance phenomenon. The principles of magnetic resonance phenomena mainly include: the method comprises the following steps that (1) atomic nuclei containing odd protons, such as hydrogen atomic nuclei widely existing in a human body, protons of the atomic nuclei have spinning motion just like a small magnet, the spin axes of the small magnets do not have a certain rule, and if an external magnetic field is applied, the small magnets are rearranged according to the magnetic lines of the external magnetic field, specifically, the small magnets are arranged in two directions parallel or antiparallel to the magnetic lines of the external magnetic field, the direction parallel to the magnetic lines of the external magnetic field is called as a positive longitudinal axis, and the direction antiparallel to the magnetic lines of the external magnetic field is called as a negative longitudinal axis; the nuclei have only a longitudinal magnetization component, which has both a direction and an amplitude. The magnetic resonance phenomenon is a phenomenon in which nuclei in an external magnetic field are excited by a Radio Frequency (RF) pulse of a specific Frequency such that the spin axes of the nuclei deviate from the positive longitudinal axis or the negative longitudinal axis to generate resonance. After the spin axes of the excited nuclei are shifted from the positive or negative longitudinal axes, the nuclei have a transverse magnetization component. After the emission of the radio frequency pulse is stopped, the excited atomic nucleus emits an echo signal, absorbed energy is gradually released in the form of electromagnetic waves, the phase and the energy level of the electromagnetic waves are restored to the state before the excitation, and the image can be reconstructed by further processing the echo signal emitted by the atomic nucleus through space coding and the like.

In magnetic resonance imaging, HF coils (local coils) are used to receive alternating magnetic fields. In order to achieve a good signal-to-noise ratio, the geometry and the reception profile of the HF coil need to be optimized for different body parts. At the same time, in order to ensure a signal-to-noise ratio as high as possible, the local coil is usually positioned as close as possible to the body of the subject or patient. For further transmission of the magnetic resonance signals from the local coil to the signal processing system, shielded coaxial cables are usually employed. The local coil is connected to a first coaxial cable that is plugged into the examination table. A further coaxial cable is connected to the connector of the examination table, which leads the magnetic resonance signals out of the examination table and onward to a signal processing system.

Due to the electric field and the magnetic field formed at the transmission or reception stage of the high-frequency pulse, a high-frequency current is induced on the wire cover (metal shield layer) of the coaxial cable. Without appropriate suppression measures, image disturbances can result and in the worst case, risks to the patient.

In order to suppress the generation of high-frequency currents, wave traps integrated in the patient bed are used. The wave trap is mainly used for inhibiting common-mode signals on the radio frequency cable from generating large current and preventing a patient from being burnt. The wave trap generates a suppression signal at the working frequency point of nuclear magnetic resonance according to the principle that resonance is generated by capacitance and inductance.

A trap is essentially a resonant circuit, or an inductor of an automatic switch, used in an electrical circuit to filter out signals of unwanted frequencies, such as a trap added at the edge of the passband of a bandpass filter, usually connected in series with a parallel resonant tank or in parallel with a series tank, whose resonant frequency is the frequency to be filtered out.

A trap is a special band-stop filter, the stop band of which ideally has only one frequency point and is therefore also referred to as a point-stop filter. Such filters are mainly used to eliminate interference at a certain frequency.

As described in the background art, two types of wave traps exist in the prior art, one type of wave trap is provided with a capacitor only at one end of a shielding sleeve, so that the heat generation is too concentrated, the ignition is easy, and the defect is particularly obvious when the size of a winding bracket is small; another type of Trap is the floating Trap, and the capacitance of this type of Trap is exposed at the surface, and has a large influence on the local B1 field, which affects the imaging.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a wave trap according to an embodiment of the utility model.

In this embodiment, the wave trap comprises a support 10 and a shielding sleeve 20, wherein: an inductance element is arranged on the bracket 10; the shielding sleeve 20 is sleeved on the support 10, and at least two capacitor assemblies are arranged on the shielding sleeve 20.

In order to suppress common mode signals generated on the radio frequency cable and to suppress the generation of large currents, integrated wave traps are used which present a high ohmic impedance Z0 for high frequency currents, the high ohmic impedance Z0 being realized by means of a parallel resonant circuit. The inductive element provided on the support 10 forms a resonant circuit with the capacitive component provided on the shielding sleeve 20.

Illustratively, the inductive element is formed by winding a shielding layer of the radio frequency cable; or the steel wire is directly formed without winding.

It can be understood that the shielding sleeve 20 is a hollow cylinder, a cavity for accommodating the support 10 is formed inside the shielding sleeve 20, the support 10 passes through two ends of the shielding sleeve 20, and the inductance elements are all located in the cavity. Illustratively, the housing functions as a mechanical carrier for the electrical components disposed thereon or therein.

The wave trap comprises a bracket 10 and a shielding sleeve 20, wherein an inductance element is arranged on the bracket 10; the shielding sleeve 20 is sleeved on the support 10, at least two capacitor assemblies are arranged on the shielding sleeve 20, the voltage division effect is achieved, heating points are dispersed in at least two positions, and the ignition risk is reduced. While retaining the shielding sleeve 20, the advantage of the trap being less influential on the local B1 field is retained.

In another embodiment, the shielding sleeve 20 is a cylinder.

The inner side of the shielding sleeve 20 forms, for example, a spatially limited cavity, the cross section of which or the shape of the cross section and the inner diameter can be set as desired. The cross-section of the cavity, or the shape of the cross-section, may be arranged to be circular or nearly circular, whereby a higher trap quality is obtained, since the magnetic losses occurring in the magnetic circuit are relatively small in this shape, but also an elliptical or other shape may be used.

It is understood that in other embodiments, the shielding sleeve 20 may be a hollow cylinder with other shapes, as long as it is ensured that a cavity for accommodating the bracket 10 is formed inside, for example, a rectangular parallelepiped, for example, a cylinder with a trapezoidal cross section, which is not limited herein.

In another embodiment, the shielding sleeve 20 is provided with two capacitive components, which are respectively arranged on two bottom surfaces of the shielding sleeve 20.

In this embodiment, the capacitive component is a capacitive plate, the shape of which matches the shape of the bottom surface of the shielding sleeve 20. Illustratively, if the shielding sleeve 20 is a cylinder, the shape of the capacitor plate is circular, and it will be understood that, in order to pass the support 10 through the shielding sleeve 20, the center of the capacitor plate may be perforated to pass the support 10. In other embodiments, the capacitor assembly may be in other forms, and only needs to match the shape of the bottom surface of the shielding sleeve 20, and is not limited herein.

Illustratively, the capacitor assembly includes a first capacitor plate 21 and a second capacitor plate 22, which are disposed at two ends of the shielding sleeve 20 as the bottom surface of the cylinder. It is understood that in other embodiments, the number of the capacitor plates may not be limited to two, and may also be disposed at other positions on the outer surface of the shielding sleeve 20, which is not limited herein.

In the above embodiment, two of the capacitor plates are disposed on the bottom surface of the shielding sleeve 20, not directly exposed to the surface, reducing the effect on the local B1 field.

In another embodiment, the inductive element is a coil wound by a shielding layer of a radio frequency cable, and the coil is wound on the bracket 10.

It can be understood that the coil in the circuit is formed by winding the shielding layer of the radio frequency cable, which means that the wires are wound one by one along the support 10, the wires are insulated from each other, the support is made of non-metal material, and the support 10 may be hollow.

In other embodiments, the inductance element is disposed on the bracket 10, and is not limited herein.

In another embodiment, the support 10 is provided with a helical groove for receiving the coil.

It will be appreciated that in other embodiments, the helical groove may not be provided, and the coil may be wound directly around the outer surface of the stent 10.

In the above embodiment, the coil is wound along the spiral groove by arranging the spiral groove on the bracket 10, so that the wound coil is prevented from falling off.

In another embodiment, the stent 10 is machined from a non-metallic material.

It is understood that in other embodiments, the bracket 10 may be made of other conductive metals, and is not limited herein.

In another embodiment, the shielding sleeve 20 is formed from a nonmagnetic metal working.

It will be appreciated that the shield sleeve 20 acts as a shield and therefore needs to be made of a non-magnetic metal.

In other embodiments, the shielding sleeve 20 may be partially made of plastic with corresponding features that make it useful in a magnetic field environment. In such a plastic-based shielding sleeve 20, a metal layer may be injected on or under its surface. Illustratively, the material and the manufacturing method of the shielding sleeve 20 may be adjusted according to the requirement, and only the shielding function is required, and is not particularly limited herein.

In another embodiment, the stent 10 is a cylinder.

It is understood that in other embodiments, the support 10 may have other shapes, and is not limited thereto.

In another embodiment, the inductive element may be an adjustable inductor. Specifically, the support 10 is provided with a through hole extending in the axial direction, a spiral groove is formed in the periphery of the support 10, and the coil is wound in the spiral groove. Each helical groove of the bracket 10 is provided with a notch therein, which is in communication with the through hole. By providing the cut, the stent 10 can be compressed or stretched in the axial direction, so as to correspondingly adjust the size of the inductance formed by the coil wound in the spiral groove, specifically, when the stent 10 is compressed, the corresponding inductance becomes larger, and when the stent 10 stretches, the corresponding inductance becomes smaller. Specifically, the amount of expansion of the bracket 10 can be controlled by a screw passing through the through hole and a nut assembled on the screw. The nut is located on the outside of the bracket 10.

The utility model also provides a radio frequency coil assembly, which comprises a radio frequency coil, a cable connected with the radio frequency coil and the wave trap, wherein the wave trap is connected to the cable. The wave trap comprises a bracket 10 and a shielding sleeve 20, wherein an inductance element is arranged on the bracket 10; the shielding sleeve 20 is sleeved on the support 10, and at least two capacitor assemblies are arranged on the shielding sleeve 20.

The utility model also provides a magnetic resonance imaging system which comprises the radio frequency coil assembly.

In the description herein, references to the description of "some embodiments," "other embodiments," "desired embodiments," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the utility model. In this specification, a schematic description of the above terminology may not necessarily refer to the same embodiment or example.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the utility model. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, and these are all within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. A wave trap comprising a support (10) and a shielding sleeve (20), wherein:

an inductance element is arranged on the bracket (10);

the shielding sleeve (20) is sleeved on the support (10), and at least two capacitor assemblies are arranged on the shielding sleeve (20).

2. The wave trap according to claim 1, characterized in that the shielding sleeve (20) is a cylinder.

3. The wave trap according to claim 2, characterized in that the shielding sleeve (20) is provided with two capacitive components, which are arranged at two bottom surfaces of the shielding sleeve (20), respectively.

4. The wave trap according to claim 1, characterized in that the inductive element is a coil, which is wound on the support (10).

5. The wave trap according to claim 4, characterized in that the holder (10) is provided with helical grooves for accommodating the coils.

6. The wave trap according to claim 1, characterized in that the bracket (10) is machined from a non-metallic material.

7. The wave trap according to claim 1, characterized in that the shielding sleeve (20) is formed of a nonmagnetic metal working.

8. The wave trap according to claim 1, characterized in that the support (10) is a cylinder.

9. A radio frequency coil assembly comprising a radio frequency coil, a cable connected to the radio frequency coil, and a wave trap according to any of claims 1-8, the wave trap being connected to the cable.

10. A magnetic resonance imaging system comprising a radio frequency coil assembly as claimed in claim 9.

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