CN217506104U

CN217506104U - Transmitting coil assembly and magnetic resonance system

Info

Publication number: CN217506104U
Application number: CN202220931229.7U
Authority: CN
Inventors: 肖康达
Original assignee: Shanghai United Imaging Healthcare Co Ltd
Current assignee: Shanghai United Imaging Healthcare Co Ltd
Priority date: 2022-04-21
Filing date: 2022-04-21
Publication date: 2022-09-27
Anticipated expiration: 2032-04-21

Abstract

The present application relates to a transmit coil assembly and a magnetic resonance system. A transmit coil assembly comprising: the supporting frame is arranged to be a cylindrical structure, and one or more grooves are formed in the inner wall surface of the cylindrical structure; the transmitting coil is arranged on the outer surface of the supporting frame to form a radio frequency transmitting field; local shim coils disposed within the slots and drivable to produce a local magnetic field. The embodiment of the application can improve the image quality of the magnetic resonance image.

Description

Transmitting coil assembly and magnetic resonance system

Technical Field

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

Background

The magnetic resonance system may utilize magnetic resonance imaging techniques for medical imaging. Because magnetic resonance imaging can obtain a clear image with high contrast inside a detected object without damage, the magnetic resonance imaging is widely applied to various fields, particularly the medical field.

In a magnetic resonance system, the magnetic field uniformity of the main magnet largely determines the quality of a magnetic resonance image, such as the signal-to-noise ratio, the spatial resolution, and the like of the magnetic resonance image.

In view of this, how to provide a uniform magnetic field environment in the magnetic resonance scanning process to improve the image quality of the magnetic resonance image is an urgent problem to be solved at present.

Disclosure of Invention

The embodiment of the application provides a transmitting coil assembly and a magnetic resonance system, which can improve the image quality of a magnetic resonance image.

In a first aspect, an embodiment of the present application provides a transmitting coil assembly, including:

the supporting frame is of a cylindrical structure, and one or more grooves are formed in the inner wall surface of the cylindrical structure;

the transmitting coil is arranged on the outer surface of the supporting frame to form a radio frequency transmitting field;

local shim coils disposed within the slots and drivable to produce a local magnetic field.

In one embodiment, the groove extends in a circumferential direction on an inner wall surface of the cylindrical structure to form an arc-shaped structure.

In one embodiment, a plurality of grooves are formed in the inner wall surface of the cylindrical structure, and the grooves are distributed side by side along the axial direction of the support frame.

In one embodiment, one or more axial communication grooves are further formed in the inner wall surface of the cylindrical structure, and each axial communication groove is communicated with a plurality of grooves.

In one embodiment, a plurality of axial communication grooves are formed in the inner wall surface of the cylindrical structure, and the axial communication grooves are distributed side by side along the circumferential direction of the support frame.

In one embodiment, the local shim coil comprises an interconnected coil body and a pulley disposed within the groove;

the pulley is used for sliding in the groove to move the coil body.

In one embodiment, the local shim coil further comprises a connecting rod, and the coil body and the pulley are respectively connected to both ends of the connecting rod.

In one embodiment, the local shim coil further comprises a controller connected to the pulley;

the controller is used for controlling the pulley to slide in the magnetic resonance scanning process.

In one embodiment, the support frame is formed by a first support frame and a second support frame which are surrounded, and the first support frame and the second support frame are both in a semi-cylindrical structure;

the one or more grooves are arranged on the surface of the inner wall of the first support frame;

or the one or more grooves are formed in the inner wall surface of the first support frame and the inner wall surface of the second support frame.

In a second aspect, an embodiment of the present application provides a magnetic resonance system, including:

a main magnet surrounding a scanning bore and capable of forming a main magnetic field within the scanning bore;

the supporting frame is arranged in the scanning cavity and forms a cylindrical structure;

the transmitting coil is arranged between the main magnet and the support frame and is used for forming a radio frequency transmitting field;

and the local shimming coil is arranged on the inner surface of the support frame and used for adjusting the uniformity of the main magnetic field.

The transmitting coil assembly comprises a support frame, a transmitting coil and a local shimming coil, wherein the support frame is of a cylindrical structure, and one or more grooves are formed in the inner wall surface of the cylindrical structure; the transmitting coil is arranged on the outer surface of the support frame to form a radio frequency transmitting field; local shim coils are arranged in the grooves and can be driven to generate a local magnetic field; in this way, the local shimming coils are disposed in the grooves on the inner wall surface of the cylindrical structure and can be driven to generate a local magnetic field, so that in the magnetic resonance scanning process, under the condition that the magnetic field at the scanning part is not uniform, the local shimming coils can be moved to the scanning part to generate the local magnetic field, shimming of the main magnetic field corresponding to the scanning part is realized, a uniform magnetic field environment is provided in the magnetic resonance scanning process, and the image quality of the magnetic resonance image is improved.

Drawings

FIG. 1 is a schematic diagram of an exemplary transmit coil assembly in one embodiment;

FIG. 2 is a schematic diagram of an exemplary transmit coil assembly in another embodiment;

FIG. 3 is a schematic diagram of an exemplary transmit coil assembly in another embodiment;

FIG. 4 is a schematic diagram of an exemplary local shim coil configuration in another embodiment;

FIG. 5 is a schematic diagram of an exemplary transmit coil assembly in another embodiment;

FIG. 6 is a schematic diagram of a field map obtained by shimming simulation of a human brain by using main shimming coils in another embodiment;

fig. 7 is a field diagram schematically illustrating shimming simulation of a human brain by using the main shim coil in combination with the local shim coil according to the embodiment of the present application in another embodiment.

Description of reference numerals:

a main shim coil: 90, respectively; a support frame: 100, respectively; groove: 110; axial communicating groove: 120 of a solvent; a transmitting coil: 200 of a carrier; local shim coils: 300, respectively; a coil body: 310; pulley: 320, a first step of mixing; connecting rods: 330.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application more clearly understood, the embodiments of the present application are described in further detail below with reference to the accompanying drawings and the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the embodiments of the application and are not intended to limit the embodiments of the application.

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 the embodiments of the present application belong. The terminology used in the description of the embodiments of the present application in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the embodiments of the present application.

It is to be understood that the terms "first," "second," and the like, as used in the embodiments of the present application, may be used in the embodiments of the present application to describe various elements, but the elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, a first resistance may be referred to as a second resistance, and similarly, a second resistance may be referred to as a first resistance, without departing from the scope of embodiments herein. The first resistance and the second resistance are both resistances, but they are not the same resistance.

It is to be understood that "connection" in the following embodiments is to be understood as "electrical connection", "communication connection", and the like if the connected circuits, modules, units, and the like have communication of electrical signals or data with each other.

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," etc., 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.

To facilitate an understanding of the embodiments of the present application, the embodiments of the present application will be described more fully below with reference to the accompanying drawings. Examples of the embodiments of the present application are given in the accompanying drawings. The embodiments of the present 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.

Referring to fig. 1, embodiments of the present application provide a transmit coil assembly including a support frame 100, a transmit coil 200, and local shim coils 300.

The transmit coil assembly may be used in a magnetic resonance system to form a radio frequency transmit field and to generate a local magnetic field. Illustratively, the transmit coil assembly may be disposed within a scan bore formed around a main magnet of the magnetic resonance system.

In the embodiment of the present application, the supporting frame 100 is provided as a cylindrical structure.

Wherein the cylindrical structure may be adapted to the shape of the main magnet of the magnetic resonance system, such that the support 100 may be arranged in the scanning bore formed around the main magnet. Illustratively, the support frame 100 is disposed in a scanning bore formed around the main magnet, and the main magnet and the support frame 100 are disposed in concentric tubes.

The supporting frame 100 may be made of a non-metal material, so that the supporting frame 100 may avoid interfering with the rf transmitting field formed by the transmitting coil 200. The inner cavity of the support 100 is a space for magnetic field scanning of the magnetic resonance system, and the lying position of the scanned object is arranged in the space when the scanned object is diagnosed.

In the present embodiment, one or more grooves 110 (fig. 1 shows only one exemplary groove 110) are formed on the inner wall surface of the cylindrical structure.

Hereinafter, an embodiment in which the inner wall surface of the cylindrical structure is provided with one groove 110 will be described as an example. It should be noted that the grooves 110 shown in fig. 1 do not limit the shape, number and distribution of the grooves 110 on the inner wall surface of the cylindrical structure according to the embodiment of the present application.

In the case where the inner wall surface of the cylindrical structure is provided with one groove 110, for example, the groove 110 may extend in the circumferential direction on the inner wall surface of the cylindrical structure to form an arc-shaped structure, for example, the groove 110 may be a semicircular structure provided in a region of the inner wall surface of the cylindrical structure corresponding to a region above the scanned object lying when the scanned object is diagnosed; illustratively, the groove 110 may extend in a circumferential direction on an inner wall surface of the cylindrical structure to form a circular structure; the grooves 110 may also be helical, for example, and the grooves 110 may be spirally distributed along the axial direction on the inner wall surface of the cylindrical structure; the groove 110 may also, for example, extend in the axial direction on the inner wall surface of the cylindrical structure, etc.

As for the embodiment in which the inner wall surface of the cylindrical structure is provided with a plurality of grooves 110, it will be described in the following examples.

And the transmitting coil 200 is arranged on the outer surface of the support frame 100 to form a radio frequency transmitting field. The transmitting coil 200 is a radio frequency coil, in this embodiment, the transmitting coil 200 may be a body transmitting coil, and the transmitting coil 200 may be attached to the outer surface of the supporting frame 100 in a surrounding manner.

Local shim coils 300, disposed within the slots 110, can be driven to produce a local magnetic field.

The local shim coil 300 may be an annular coil, and the local shim coil 300 may be slidably disposed in the groove 110, so that the local shim coil 300 may be slid to any position in the groove 110, and after the local shim coil 300 is slid to any position, the local shim coil 300 is energized with a current, so that a local magnetic field may be generated to shim a main magnetic field at the any position.

Hereinafter, a principle of generating a local magnetic field by the local shim coil 300 according to the embodiment of the present invention to shim a main magnetic field corresponding to a scanning region of a scanning target will be described.

In the case of the transmit coil assembly being used in a magnetic resonance system, the subject being scanned lies in a lying position, the magnetic resonance system may calculate the magnetic field inhomogeneity position of the main magnetic field, for example, the magnetic resonance system may perform a dual-echo sequence scan on the subject being scanned to obtain field map information, shim the subject using the main shim coil 90, then calculate the magnetic field inhomogeneity position based on the residual field map information, then control the local shim coil 300 to slide to the magnetic field inhomogeneity position, and apply a current to the local shim coil 300, where the current may be of a magnitude that the magnetic resonance system uses the field map information to calculate a current required by the local shim coil 300 to shim, so that the local shim coil 300 applies the current to generate a local magnetic field that may shim the main magnetic field at the magnetic field inhomogeneity position. After the local magnetic field generated by the local shimming coil 300 is shimmed, a uniform magnetic field environment can be obtained at the position of the magnetic field nonuniformity, so that the image quality of the magnetic resonance image can be improved.

In the embodiment of the present application, the number of the local shim coils 300 may be one or more, and when the number of the local shim coils 300 is more than one, the local shim coils 300 may shim at different magnetic field inhomogeneity positions simultaneously, so as to improve the shimming effect.

In summary, the transmitting coil assembly of the above embodiment includes a support frame 100, a transmitting coil 200, and a local shim coil 300, wherein the support frame 100 is configured as a cylindrical structure, and one or more grooves 110 are formed on an inner wall surface of the cylindrical structure; the transmitting coil 200 is arranged on the outer surface of the support frame 100 to form a radio frequency transmitting field; local shim coils 300 disposed within the slots 110 can be driven to produce a local magnetic field; in this way, by arranging the local shim coils 300 in the grooves 110 on the inner wall surface of the cylindrical structure, and driving the local shim coils 300 to generate a local magnetic field, the local shim coils 300 can be moved to the scanning portion to generate a local magnetic field during the magnetic resonance scanning process, so that the shimming of the main magnetic field corresponding to the scanning portion is realized, a uniform magnetic field environment is provided during the magnetic resonance scanning process, and the image quality of the magnetic resonance image is improved.

In one embodiment, based on the embodiment shown in fig. 1, referring to fig. 2, in the present embodiment, a plurality of grooves 110 are formed on an inner wall surface of the cylindrical structure, and the plurality of grooves 110 are distributed side by side along an axial direction of the support frame 100.

As shown in fig. 2, in the case that the inner wall surface of the cylindrical structure is provided with a plurality of grooves 110, for example, the plurality of grooves 110 are distributed side by side along the axial direction of the supporting frame 100, and each of the plurality of grooves 110 may extend along the circumferential direction on the inner wall surface of the cylindrical structure to form an arc-shaped structure, for example, each of the grooves 110 may be a semicircular structure and is disposed in a region corresponding to the inner wall surface of the cylindrical structure above the lying position of the scanned object in diagnosis.

It is to be understood that the plurality of grooves 110 shown in fig. 2 do not constitute a limitation on the shape, number, and distribution pattern of the plurality of grooves 110 on the inner wall surface of the cylindrical structure in the embodiment of the present application, for example, each of the plurality of grooves 110 may extend in the circumferential direction on the inner wall surface of the cylindrical structure to form a circular structure, and the like.

In the embodiment of the present application, in the case that the number of the grooves 110 is multiple, the number of the local shim coils 300 may be one or multiple, and each local shim coil 300 may slide in each groove 110 to shim the main magnetic field at the magnetic field inhomogeneity position.

In the above embodiment, the plurality of grooves 110 are formed on the inner wall surface of the cylindrical structure, so that the movable range of the local shim coil 300 is increased, the shim range is expanded, and the shim effect and the image quality of the magnetic resonance image are further improved.

In one embodiment, based on the embodiment shown in fig. 2, the present embodiment further opens one or more axial communication grooves 120 on the inner wall surface of the cylindrical structure, and each axial communication groove 120 is communicated with the plurality of grooves 110.

Referring to fig. 3, in the case where a plurality of axial communication grooves 120 are opened on the inner wall surface of the cylindrical structure, the plurality of axial communication grooves 120 are distributed side by side in the circumferential direction of the support frame 100.

In this embodiment, the grooves 110 extend in the circumferential direction on the inner wall surface of the cylindrical structure, and therefore, the grooves 110 may serve as a slide rail for the local shim coils 300 to move in the circumferential direction of the inner wall surface; the axial communication slots 120 extend in the axial direction of the inner wall surface, and therefore, the axial communication slots 120 may serve as slide rails for the local shim coil 300 to move in the axial direction of the inner wall surface; the axial communication grooves 120 are communicated with the plurality of grooves 110, so that the local shim coils 300 can slide into the axial communication grooves 120 or the grooves 110 without moving out of the grooves 110 or the axial communication grooves 120, and can freely move on the inner wall surface of the cylindrical structure along the circumferential direction and the axial direction, thereby improving the movement flexibility of the local shim coils 300 and being beneficial to improving the shimming effect.

In one embodiment, based on the embodiment shown in fig. 1, referring to fig. 4, the local shim coil 300 of the present embodiment includes a coil body 310 and a pulley 320 connected to each other, the pulley 320 being disposed within the groove 110; the pulley 320 is adapted to slide within the groove 110 to move the coil body 310.

The local shim coil 300 further includes a connecting rod 330, and the coil body 310 and the pulley 320 are respectively connected to both ends of the connecting rod 330.

Thus, where the transmit coil assembly is used in a magnetic resonance system in which the subject to be scanned lies, the magnetic resonance system may calculate the magnetic field inhomogeneity location of the main magnetic field, and then the magnetic resonance system controls the pulley 320 to be slidably positioned to the magnetic field inhomogeneity location, thereby driving the local shim coils 300 to be slidably positioned to the magnetic field inhomogeneity location.

As an embodiment, the local shim coil 300 further includes a controller coupled to the pulley 320 for controlling the pulley 320 to slide during the magnetic resonance scan. The controller may be, for example, a linear actuator.

For example, the magnetic resonance system may acquire a magnetic field analog signal of the main magnetic field, perform analog-to-digital conversion, position calculation, and the like to obtain a magnetic field non-uniform position, perform digital-to-analog conversion to obtain a digitized indication signal, and send the indication signal to the controller, which controls the pulley 320 to move to the magnetic field non-uniform position.

Further, after the magnetic resonance system acquires the magnetic field analog signal of the main magnetic field, shimming calculation and other processing may be performed to obtain shim currents, the shim currents are amplified by the power amplifier and then applied to the local shim coil 300, and a local magnetic field may be generated after the local shim coil 300 is supplied with current, and the local magnetic field may shim the main magnetic field at a position where the magnetic field is not uniform. After the local magnetic field generated by the local shimming coil 300 is shimmed, a uniform magnetic field environment can be obtained at the position of the magnetic field nonuniformity, so that the image quality of the magnetic resonance image can be improved.

In one embodiment, based on the embodiment described in any of fig. 1 to 3, in this embodiment, the supporting frame 100 is formed by surrounding a first supporting frame and a second supporting frame, and both the first supporting frame and the second supporting frame are semi-cylindrical structures.

For example, assuming that the lying position of the scanned object is used as a dividing reference in diagnosis, the support 100 above the lying position is a first support, and the support 100 below the lying position is a second support.

In one possible embodiment, one or more grooves 110 are provided on the inner wall surface of the first support frame, for example, the grooves 110 are distributed as shown in fig. 1, 2 or 3.

In another possible embodiment, one or more recesses 110 are provided in the inner wall surface of the first support bracket and the inner wall surface of the second support bracket. Illustratively, referring to fig. 5, a plurality of grooves 110 are provided on the inner wall surface of the first support bracket and the inner wall surface of the second support bracket, i.e., each groove 110 extends in the circumferential direction on the inner wall surface of the cylindrical structure to form a circular structure. Thus, the movable range of the local shimming coil 300 is further increased, so that the shimming range is expanded, and the shimming effect and the image quality of the magnetic resonance image are further improved.

In the related art, in order to provide a uniform magnetic field environment, shimming is realized by using a plurality of groups of shim coils (such as A10, B11, A11, A20, A21, B21, A22 and B22) in the active shimming process. For some parts of a patient with severe magnetic field changes (such as the head and the neck), and parts close to the edge of the magnet (such as the chest and the abdomen), higher-order shimming coils are generally needed in the active shimming process, but when the high-order shimming coils are used, the structural design of the coils is more complicated and the cost is increased, and the efficiency and the power consumption of the coils are increased sharply. Meanwhile, the eddy current and mutual inductance of each coil affect the final imaging effect. In the embodiment of the application, shimming can be realized through the local shimming coil, the coil structure is simple, cost control is facilitated, and the shimming effect can be better improved, so that the imaging effect is improved.

Referring to fig. 6 and 7, fig. 6 is a schematic diagram of a field map obtained by performing shimming simulation calculation on the human brain by using main shim coils (including a10, B11, a11, a20, a21, B21, a22 and B22) exemplarily; fig. 7 is a schematic view of a field pattern obtained by performing shimming simulation calculation on the human brain by exemplarily using the main shimming coil and combining the local shimming coil according to the embodiment of the present application.

In fig. 6, the human brain is shimmed only by the main shimming coil, and the standard deviation of the magnetic field after shimming is about 42 Hz; in fig. 7, the human brain is shimmed using the main shim coils in combination with the local shim coils of the embodiments of the present application, with a standard deviation of about 22Hz after shimming.

Through comparison, the main shimming coil is combined with the local shimming coil to shim the human brain, the standard deviation of the magnetic field is reduced by about 48%, and the uniformity of the magnetic field is greatly improved.

In one embodiment, there is provided a magnetic resonance system comprising: the main magnet surrounds to form a scanning cavity, and the main magnet can form a main magnetic field in the scanning cavity; the supporting frame is arranged in the scanning cavity and forms a cylindrical structure; the transmitting coil is arranged between the main magnet and the support frame and is used for forming a radio frequency transmitting field; the shimming coil is arranged on the inner surface of the support frame and used for finely adjusting the uniformity of the main magnetic field; and the main shimming coil is arranged between the main magnet and the support frame and used for generating magnetic fields of all levels to realize the rough adjustment of the uniformity of the main magnetic field.

For the implementation of the support frame, the transmitting coil, the local shimming coil, and the shimming process, reference may be made to the above-mentioned embodiments, which are not described herein again.

All possible combinations of the technical features in the above embodiments may not be described for the sake of brevity, but should be considered as being within the scope of the present disclosure as long as there is no contradiction between the combinations of the technical features.

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

Claims

1. A transmit coil assembly, comprising:

the supporting frame (100) is arranged into a cylindrical structure, and one or more grooves (110) are formed in the inner wall surface of the cylindrical structure;

a transmitting coil (200) disposed on an outer surface of the support frame (100) to form a radio frequency transmitting field;

local shim coils (300) disposed within the slots (110) are drivable to produce a local magnetic field.

2. The transmit coil assembly of claim 1 wherein the groove (110) extends in a circumferential direction at an inner wall surface of the cylindrical structure to form an arcuate structure.

3. The transmitting coil assembly according to claim 1 or 2, wherein a plurality of the grooves (110) are formed on the inner wall surface of the cylindrical structure, and the plurality of the grooves (110) are distributed side by side along the axial direction of the support frame (100).

4. The transmit coil assembly of claim 3 wherein one or more axial communication grooves (120) are further defined in the inner wall surface of the cylindrical structure, and each axial communication groove (120) is in communication with a plurality of the grooves (110).

5. The transmitting coil assembly according to claim 4, wherein a plurality of the axial communication grooves (120) are formed in the inner wall surface of the cylindrical structure, and the plurality of the axial communication grooves (120) are distributed side by side along the circumferential direction of the support frame (100).

6. The transmit coil assembly of claim 1, wherein the local shim coil (300) comprises an interconnected coil body (310) and a pulley (320), the pulley (320) disposed within the groove (110);

the pulley (320) is configured to slide within the groove (110) to move the coil body (310).

7. The transmit coil assembly of claim 6, wherein the local shim coil (300) further comprises a connecting rod (330), the coil body (310) and the pulley (320) being connected to both ends of the connecting rod (330), respectively.

8. The transmit coil assembly of claim 6, wherein the local shim coil (300) further comprises a controller connected to the pulley (320);

the controller is used for controlling the pulley (320) to slide in the magnetic resonance scanning process.

9. The transmit coil assembly of claim 1 wherein the support frame (100) is defined by a first support frame and a second support frame, the first support frame and the second support frame each being a semi-cylindrical structure;

the one or more grooves (110) are arranged on the inner wall surface of the first support frame;

alternatively, the one or more recesses (110) are provided on an inner wall surface of the first support bracket and an inner wall surface of the second support bracket.

10. A magnetic resonance system, comprising:

the supporting frame (100) is arranged in the scanning cavity and forms a cylindrical structure;

a transmitting coil (200) disposed between the main magnet and the support frame (100) for forming a radio frequency transmitting field;

local shim coils (300) arranged on the inner surface of the support frame (100) for adjusting the homogeneity of the main magnetic field.