CN219831358U - Knee joint radio frequency coil device and magnetic resonance imaging system - Google Patents

Abstract

The utility model relates to a knee joint radio frequency coil device for a magnetic resonance imaging system, which comprises a shell with a containing space and a coil circuit arranged in the shell, wherein the coil circuit comprises three groups of unit coils: a first set of unit coils circumferentially overlying the knee joint; and each two adjacent unit coils are partially overlapped; a second set of unit coils circumferentially covering the distal end of the knee joint; the third group of unit coils are covered on the proximal end of the knee joint in a surrounding way; and each partially overlaps with a coil unit in the adjacent first group of unit coils. The utility model effectively expands the imaging space of the knee joint coil and improves the signal to noise ratio. The unit coils at the two ends of the coil are isolated from each other, so that the use of the radio frequency connector is reduced, the fault probability is reduced, the coil cost is saved, and the debugging difficulty of the coil is reduced. The utility model also comprises a magnetic resonance imaging system using the knee joint radio frequency coil device, and the knee joint imaging performance of the magnetic resonance imaging system is improved.

Description

Knee joint radio frequency coil device and magnetic resonance imaging system

Technical Field

The utility model relates to a knee joint radio frequency coil device for a magnetic resonance imaging system and the magnetic resonance imaging system.

Background

The magnetic resonance imaging system is a large medical diagnostic apparatus and is widely used in modern hospitals. Magnetic resonance imaging systems are devices that generate two-or three-dimensional images of human tissue according to the principles of magnetic resonance imaging, common magnetic resonance imaging systems generally comprise: generating a static homogeneous magnetic field B ₀ Is a main magnet of (a); the radio frequency system comprises a radio frequency coil for exciting human tissue to generate magnetic resonance and receiving resonance signals; a gradient system for generating a gradient magnetic field in an imaging space and imaging coding; and a computer imaging system for processing the magnetic resonance signals to generate visual images for viewing by a physician.

In a magnetic resonance system, both excitation and reception of the radio frequency magnetic field are accomplished by radio frequency coils. For radio frequency receiving coils, it is important to improve the signal-to-noise ratio. To cover a large imaging area, radio frequency coils often require the use of multiple coils to surround the object to be imaged. Probing and diagnosing lesions of the knee joint and surrounding tissues using magnetic resonance methods is popular with doctors and patients. The signal-to-noise ratio of the knee radio frequency coil arrangement, however, is highly desirable for imaging volumes large enough.

Disclosure of Invention

The utility model provides a knee joint radio frequency coil device for a magnetic resonance imaging system and the magnetic resonance imaging system, which aim to solve the problem that the current magnetic resonance imaging system is insufficient in the signal-to-noise ratio of the knee joint radio frequency coil device.

In order to solve the problems, the technical scheme adopted by the utility model is as follows:

a knee joint radio frequency coil device comprises a shell with a containing space and a coil circuit arranged in the shell; the coil circuit includes a ring-shaped coil unit; the coil circuit comprises three groups of unit coils, wherein coil units in the three groups of unit coils respectively form three coaxial column surfaces which are adjacent in the axial direction;

the first group of unit coils includes a first coil unit 1, a second coil unit 2, a third coil unit 3, a fourth coil unit 4, a fifth coil unit 5, a sixth coil unit 6, a seventh coil unit 7, and an eighth coil unit 8; the first coil unit 1 to the eighth coil unit 8 are connected end to end and are covered on the knee joint in a surrounding manner; and the area enclosed by each two adjacent unit coils is partially overlapped;

the second group of unit coils includes a ninth coil unit 9, a tenth coil unit 10, an eleventh coil unit 11, and a twelfth coil unit 12, which are circumferentially covered on the distal end of the knee joint; each coil unit in the second group of unit coils is respectively overlapped with a part of the coil units in the adjacent first group of unit coils in the surrounding area;

the third group of unit coils comprises a thirteenth coil unit 13, a fourteenth coil unit 14, a fifteenth coil unit 15 and a sixteenth coil unit 16 which are circumferentially covered on the proximal end of the knee joint; each coil unit in the third group of unit coils is enclosed by an area which is overlapped with a part of the coil unit in the adjacent first group of unit coils respectively.

The knee joint radio frequency coil device comprises a shell, a coil and a coil, wherein the shell comprises an inner shell close to an imaging part of a human body and an outer shell matched with the inner shell to form an accommodating space; the middle part of the inner shell is smaller in size, and the sizes of the inner shell in the directions towards the two ends are gradually increased.

The knee joint radio frequency coil device, wherein the first coil unit 1, the second coil unit 2, the eighth coil unit 8, the ninth coil unit 9, the twelfth coil unit 12, the thirteenth coil unit 13 and the sixteenth coil unit 16 are covered on the front side of the knee joint;

the third coil unit 3 and the seventh coil unit 7 are respectively covered on the left side and the right side of the knee joint;

the fourth coil unit 4, the fifth coil unit 5, the sixth coil unit 6, the tenth coil unit 10, the eleventh coil unit 11, the fourteenth coil unit 14 and the fifteenth coil unit 15 are covered on the posterior side of the knee joint.

The knee joint radio frequency coil device, the coil circuit is attached to the inner shell.

In one embodiment of the knee radio frequency coil device of the present utility model, the inner and outer shells of the housing comprise two separable portions.

The knee joint radio frequency coil device, the third coil unit 3 and the seventh coil unit 7 each comprise two separable parts and are respectively arranged in the two parts of the shell.

The distance between adjacent coil units in the second group of unit coils and the third group of unit coils is more than 10mm and less than 30mm.

In one embodiment of the knee joint radio frequency coil device of the present utility model, an area enclosed by the ninth coil unit 9 is partially overlapped with an area enclosed by the first coil unit 1, the second coil unit 2, and the third coil unit 3; the area enclosed by the tenth coil unit 10 is partially overlapped with the area enclosed by the third coil unit 3, the fourth coil unit 4, and the fifth coil unit 5; the area enclosed by the eleventh coil unit 11 is partially overlapped with the areas enclosed by the fifth coil unit 5, the sixth coil unit 6, and the seventh coil unit 7; and, the area enclosed by the twelfth coil unit 12 is partially overlapped with the areas enclosed by the seventh coil unit 7, the eighth coil unit 8, and the ninth coil unit 9.

In one embodiment of the knee joint radio frequency coil device of the present utility model, the area enclosed by the thirteenth coil unit 13 is partially overlapped with the area enclosed by the first, second, and third coil units 1, 2, and 3; the area enclosed by the fourteenth coil unit 14 is partially overlapped with the area enclosed by the third coil unit 3, the fourth coil unit 4, and the fifth coil unit 5; the area enclosed by the fifteenth coil unit 15 is partially overlapped with the areas enclosed by the fifth coil unit 5, the sixth coil unit 6, and the seventh coil unit 7; and, the area enclosed by the sixteenth coil unit 16 is partially overlapped with the areas enclosed by the seventh coil unit 7, the eighth coil unit 8, and the ninth coil unit 9.

A magnetic resonance imaging system comprising any one of the aforementioned knee joint radio frequency coil arrangements.

The knee joint radio frequency coil device provided by the utility model is enclosed with 8 unit rings at the middle knee part, so that the core position signal-to-noise ratio SNR is greatly improved, and the imaging quality is good. The horn mouth shape arranged at the two ends of the coil and the four unit coils distributed respectively effectively expand the imaging space of the knee joint coil, and the knee joint coil has a larger radio frequency electromagnetic field uniform area. The unit coils at the two ends of the coil are isolated from each other, so that the use of a radio frequency connector is reduced, the fault probability of the coil is reduced, and the cost of the coil is saved; meanwhile, the debugging difficulty of the coil is reduced.

The magnetic resonance imaging system using the knee joint radio frequency coil device improves the knee joint imaging performance of the magnetic resonance imaging system.

Drawings

Fig. 1 is a schematic perspective view of a coil circuit of a knee joint radio frequency coil device of the present utility model.

Fig. 2 is an outer contour view of the knee joint radio frequency coil device of the present utility model.

Fig. 3-18 are schematic illustrations of the shape of the element coils of the knee joint radio frequency coil device of the present utility model.

Detailed Description

The utility model is described in further detail below with reference to the accompanying drawings. The implementation of the utility model is not limited to the embodiments described below, but can be implemented in many different forms. The following examples are provided to facilitate a more thorough understanding of the present disclosure.

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 utility model belongs, the terms used herein are used to describe specific embodiments only and are not intended to limit the utility model.

The knee joint radio frequency coil device of the magnetic resonance imaging system is a high-precision radio frequency antenna, the inherent resonance frequency of the high-precision radio frequency antenna is equal to the magnetic resonance frequency of the magnetic resonance system, the knee joint radio frequency coil device is in a detuned state or enters a resonance state according to an input imaging sequence in a working state, the knee joint and surrounding tissues thereof are positioned in a radio frequency electromagnetic field of the high-precision radio frequency antenna, the larger the strength of the radio frequency electromagnetic field is, the more uniform the radio frequency electromagnetic field is, the more the imaging range is full and distortion is avoided; the stronger the signal collected from the knee joint and surrounding tissue, the higher the signal to noise ratio and the more clear the image.

The electrical structure of the knee joint radio frequency coil device mainly comprises a coil body made of conductive materials and an electronic element connected in the coil body. In the working state, the output impedance is matched with the back-end data collection equipment, so that clear and noiseless image signals are derived.

The coil with excellent signal-to-noise ratio and uniformity also needs to be designed to have a coil structure that can be easily debugged, which requires that the parts of a specific coil of a corresponding structure that can realize the coil function have small influence on each other, so that the distribution of the units in the coil is a difficulty in designing the coil, and the shapes and distribution of the different units determine the performances that can be finally achieved by the coil.

Fig. 1 is a schematic perspective view of a coil circuit of a knee joint radio frequency coil device of the present utility model. The knee joint radio frequency coil device comprises 16 unit coils, wherein each unit coil is annular in an end-to-end mode, different in specific shape and size and capable of resonating at a magnetic resonance frequency. The method specifically comprises the following steps: the first coil unit 1, the second coil unit 2, the third coil unit 3, the fourth coil unit 4, the fifth coil unit 5, the sixth coil unit 6, the seventh coil unit 7, the eighth coil unit 8, the ninth coil unit 9, the tenth coil unit 10, the eleventh coil unit 11, the twelfth coil unit 12, the thirteenth coil unit 13, the fourteenth coil unit 14, the fifteenth coil unit 15, and the sixteenth coil unit 16.

As shown in fig. 1, the 16 unit coils may be divided into 3 groups: the sum of the areas covered by the first group of unit coils, the second group of unit coils and the third group of unit coils forms the surface of one column body. The 3 sets of unit coils constitute 3 coaxial, axially adjacent cylindrical surfaces.

The first group of unit coils includes a first coil unit 1, a second coil unit 2, a third coil unit 3, a fourth coil unit 4, a fifth coil unit 5, a sixth coil unit 6, a seventh coil unit 7, and an eighth coil unit 8; the first coil unit 1 to the eighth coil unit 8 are connected end to form a ring, and the enclosed areas of every two adjacent unit coils are partially overlapped and jointly enclosed and cover the surface of the knee joint.

The second group of unit coils comprises a ninth coil unit 9, a tenth coil unit 10, an eleventh coil unit 11 and a twelfth coil unit 12, which are enclosed at the position of the far end of the knee joint; each unit coil in the second group of unit coils is enclosed by an area which is partially overlapped with the unit in the adjacent first group of unit coils. But there is no overlap between adjacent element coils in the second set of element coils.

Specifically, the area enclosed by the ninth coil unit 9 overlaps with the areas enclosed by the first coil unit 1, the second coil unit 2, and the third coil unit 3; the area enclosed by the tenth coil unit 10 overlaps with the area enclosed by the third coil unit 3, the fourth coil unit 4, and the fifth coil unit 5; the area enclosed by the eleventh coil unit 11 overlaps with the areas enclosed by the fifth coil unit 5, the sixth coil unit 6, and the seventh coil unit 7; and, an area surrounded by the twelfth coil unit 12 overlaps with an area surrounded by the seventh coil unit 7, the eighth coil unit 8, and the ninth coil unit 9.

The third group of unit coils includes a thirteenth coil unit 13, a fourteenth coil unit 14, a fifteenth coil unit 15, and a sixteenth coil unit 16, which are wound around the proximal portion of the knee joint. Each unit coil in the third group of unit coils is enclosed by an area which is partially overlapped with the unit coil in the adjacent first group of unit coils. But there is no overlap between adjacent element coils in the third set of element coils.

Specifically, the area enclosed by the thirteenth coil unit 13 overlaps with the areas enclosed by the first coil unit 1, the second coil unit 2, and the third coil unit 3; the area enclosed by the fourteenth coil unit 14 is partially overlapped with the area enclosed by the third coil unit 3, the fourth coil unit 4, and the fifth coil unit 5; the area enclosed by the fifteenth coil unit 15 is partially overlapped with the areas enclosed by the fifth coil unit 5, the sixth coil unit 6, and the seventh coil unit 7; and, the area enclosed by the sixteenth coil unit 16 overlaps with the area enclosed by the seventh coil unit 7, the eighth coil unit 8, and the ninth coil unit 9.

As shown in fig. 2, which is a perspective view of an outer case of the knee joint radio frequency coil device of the present utility model, the knee joint radio frequency coil device of the present utility model further includes a case including an inner case and an outer case, and the coil electric parts shown in fig. 1 are distributed and fixed to the inner case (not shown in the drawings). The outer case and the inner case are fixed to each other to form a space accommodating the coil circuit.

In one embodiment, the knee joint radio frequency coil device of the present utility model comprises two separable parts, the two parts being electrically connected by a connector. When the two parts of the knee joint radio frequency coil device are opened, the knee joint of a patient is conveniently placed in the knee joint radio frequency coil device; and then the two parts of the knee joint radio frequency coil device are folded and locked and are electrically connected, and the magnetic resonance system can be started to scan and image after being placed in the center of the magnet.

In one embodiment, the inner and outer shells each comprise two parts, the upper and lower knee parts being separable. The inner shell in the shell is designed into an hourglass shape, the diameter of the middle part is the smallest, the inner shell is matched with the scanning part of the knee of a human body, the diameters of the inner shell and the scanning part are gradually increased to form a horn-shaped opening, the part, close to the lower leg, of the far end of the knee joint is a small horn mouth, and the part, close to the thigh, of the near end of the knee joint is a large horn mouth, so that the inner shell is in accordance with the ergonomics, the inner shell can provide larger adaptability and can be suitable for more extensive crowds.

Referring to fig. 1, the ninth coil unit 9 and the twelfth coil unit 12 are used for collecting signals of the knee joint distal end approaching the lower leg, so that they cover and are fixed at the small bell mouth position of the knee upper part of the inner shell; in addition, the thirteenth coil unit 13 and the sixteenth coil unit 16 are used to collect signals of the proximal end of the knee joint near the thigh, so that they are covered and fixed at the upper knee large bell mouth position of the inner shell. Similarly, the tenth coil unit 10 and the eleventh coil unit 11 are used for acquiring signals of the knee joint approaching the lower leg, so that they are covered and fixed at the small bell mouth position of the knee lower part of the inner shell; in addition, the fourteenth coil unit 14 and the fifteenth coil unit 15 are used to acquire signals of the knee joint approaching the thigh, so they are covered and fixed at the knee-lower large bell mouth position of the inner shell.

With continued reference to fig. 1, the first coil unit 1, the second coil unit 2 and the eighth coil unit 8 are used for acquiring a knee center position signal, covering the upper middle position of the knee of the inner shell. Similarly, the fourth coil unit 4, the fifth coil unit 5 and the sixth coil unit 6 are used for acquiring a knee center position signal, and cover the knee middle position of the inner shell; in addition, the third coil unit 3 and the seventh coil unit 7 are used for collecting signals on two sides of the whole knee, and cover the middle positions of the left side and the right side of the inner shell, one half of each coil unit is arranged on the upper part of the knee of the inner shell, the other half of each coil unit is arranged on the lower part of the knee of the inner shell, and in an operating state, the third coil unit 3 and the seventh coil unit 7 form a complete coil unit through radio frequency connectors.

As described above, the first coil unit 1, the second coil unit 2, the eighth coil unit 8, the ninth coil unit 9, the twelfth coil unit 12, the thirteenth coil unit 13, and the sixteenth coil unit 16 are for acquiring the upper signal of the entire knee, and are built in the knee upper case. The fourth coil unit 4, the fifth coil unit 5, the sixth coil unit 6, the tenth coil unit 10, the eleventh coil unit 11, the fourteenth coil unit 14, and the fifteenth coil unit 15 are for acquiring the lower signal of the entire knee, and are built in the below-knee housing.

The coil units are made of copper strips or circuit boards, and further comprise electronic components such as inductors, capacitors, detuning circuits and the like connected in the coils of the units. When the knee joint radio frequency coil device is positioned in a magnetic resonance electromagnetic field in a working state, each coil unit enters a resonance state and outputs a magnetic resonance signal to a diode amplifier through a preamplifier arranged in the coil.

Each unit coil in the knee radio frequency coil arrangement is capable of resonating at a magnetic resonance frequency. Due to the mutual coupling between adjacent unit coils, the debugging of the coil circuit is very difficult. The different arrangement modes of the plurality of unit coils and the shapes of the unit coils have great influence on the performance of the radio frequency coil, so the shapes of the unit coils and how the arrangement is in the radio frequency coil determine the performance of the radio frequency coil.

According to the knee joint radio frequency coil device, only two unit coils are respectively arranged at the left side and the right side of the knee joint, and only two pairs of radio frequency connectors are needed for conductors of the unit coils, so that the coil cost is reduced, the failure rate of a finished coil is reduced, and the reliability of the coil is improved.

In engineering practice, the high probability of failure of the radio frequency coil is caused by the damage of the radio frequency connector, and the radio frequency connector generally has 0.1-0.3 dB insertion loss, so that the number of the radio frequency connector is reduced, namely the link loss is reduced.

In the magnetic resonance imaging process, the knee joint radio frequency coil device provided by the utility model is encircled at the knee joint part of a human body, so that the knee joint of the human body can be scanned and imaged. The coil device has enough area, can completely cover the whole knee of the human body, and also has larger uniform area, higher signal-to-noise ratio and better imaging quality.

The shapes of the 16 unit coils (first coil unit 1 to sixteenth coil unit 16) are illustrated as in fig. 3 to 18, respectively. Wherein:

fig. 3 is a shape of the first coil unit 1;

fig. 4 is a shape of the second coil unit 2;

fig. 5 is a shape of the third coil unit 3;

fig. 6 is a shape of the fourth coil unit 4;

fig. 7 is a shape of the fifth coil unit 5;

fig. 8 is a shape of the sixth coil unit 6;

fig. 9 is a shape of the seventh coil unit 7;

fig. 10 is a shape of the eighth coil unit 8;

fig. 11 is a shape of the ninth coil unit 9;

fig. 12 is a shape of the tenth coil unit 10;

fig. 13 is a shape of the eleventh coil unit 11;

fig. 14 is a shape of the twelfth coil unit 12;

15 is the shape of the thirteenth coil unit 13;

fig. 16 is a shape of the fourteenth coil unit 14;

fig. 17 is a shape of the fifteenth coil unit 15; and

fig. 18 shows a sixteenth coil unit 16 as a unit coil.

As shown in fig. 3 to 18, the 16 unit coils (first coil unit 1 to sixteenth coil unit 16) are different in shape and size, and the conductors of the coil units are distributed on a curved surface.

The utility model also provides a magnetic resonance imaging system, which has clear knee joint imaging by utilizing the knee joint radio frequency coil device.

The radio frequency coil adopts an ergonomic optimization design, the inner diameter of the knee part at the center is smaller, and the shape of a horn opening is formed from the center to the two ends, so that the radio frequency coil is compatible with wider use groups.

The knee joint coil provided by the utility model surrounds a circle of 8 unit rings at the middle knee part, so that the core position signal-to-noise ratio SNR is greatly improved. The horn mouth at the far end and the near end of the knee joint are respectively provided with 4 unit rings, and the adjacent unit rings are mutually separated without area overlapping, so that the uniformity range of the radio frequency electromagnetic field is increased, a larger imaging view is provided, the knee joint imaging mainly focuses on the knee area, the imaging view is larger, and the imaging view can be used for judging the symptoms of the big and small legs close to the knee part.

The utility model separates the 4 unit rings at the two ends of the bell mouth by a proper distance, and the distance range on the circumference is 10 mm-30 mm.

In one embodiment, the image imaging area FOV of the knee joint of the present utility model is achieved by: diameter 147mm and length 200mm.

In another embodiment, the imaging area is 319X290X298mm long, wide and high, respectively.

In another embodiment, the outlet end lumen size of the knee coil is up to 230x153x190mm.

The knee joint radio frequency coil device is provided with 8 unit rings (the first group of unit coils) at the middle part, which are connected end to end, and the conductors are densely and uniformly distributed, so that the SNR is high; and the cell rings (second and third sets of cell coils) at both ends of the bell mouth intersecting the intermediate cell ring are also decoupled with overlapping areas; the unit rings (namely the second group of unit coils and the third group of unit coils) at the two ends of the bell mouth are separated from each other by a certain distance, and the distance does not influence the uniformity of the radio-frequency electromagnetic field in the central area of the knee joint and improves the decoupling effect with the middle 8 unit rings; has unexpected technical effects.

The knee joint radio frequency coil device is applied to a 3T system, and the overall performance of the knee joint radio frequency coil device is improved by more than 60% compared with that of a traditional single knee joint coil. A set of experimental data is as follows:

the experimental conditions of the above table are:

philips 3.0T commercial system, single imaging data using standard signal-to-noise ratio sequences; thick 7mm,slices 9,Gap 15mm,FOV25cm*25cm; the comparative coil is an INVIV0 8 channel single knee coil.

In the table, tn represents the number of slices scanned in the horizontal position; sn represents the number of scan slices in the sagittal position; mean (L) is the measured signal value; noise1 is the measured Noise value; total is the value of the signal to noise ratio; the ratio is the ratio of the signal to noise ratio of the inventive coil to the comparative coil.

As can be seen from the data in the table, the signal to noise ratio of the knee joint radio frequency coil device of the present utility model is up to 2.095 times that of the comparative coil, and the lowest is also up to 1.26 times.

The above examples describe in particular and in detail several embodiments of the utility model, which are not limiting to the scope of the patent claims. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit of the utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model are within the scope of the present utility model, which is defined by the appended claims.

Claims (10)

1. A knee joint radio frequency coil device comprises a shell with a containing space and a coil circuit arranged in the shell; the coil circuit includes a ring-shaped coil unit; the coil circuit is characterized by comprising three groups of unit coils, wherein coil units in the three groups of unit coils respectively form three coaxial cylinder surfaces which are adjacent in the axial direction;

the first group of unit coils includes a first coil unit 1, a second coil unit 2, a third coil unit 3, a fourth coil unit 4, a fifth coil unit 5, a sixth coil unit 6, a seventh coil unit 7, and an eighth coil unit 8; the first coil unit 1 to the eighth coil unit 8 are connected end to end and are covered on the knee joint in a surrounding manner; and the area enclosed by each two adjacent unit coils is partially overlapped;

the second group of unit coils includes a ninth coil unit 9, a tenth coil unit 10, an eleventh coil unit 11, and a twelfth coil unit 12; the ninth coil unit 9 to the twelfth coil unit 12 are circumferentially covered on the distal end of the knee joint; each coil unit in the second group of unit coils is respectively overlapped with a part of the coil units in the adjacent first group of unit coils in the surrounding area;

the third group of unit coils includes a thirteenth coil unit 13, a fourteenth coil unit 14, a fifteenth coil unit 15, and a sixteenth coil unit 16, the thirteenth coil unit 13 to the sixteenth coil unit 16 being circumferentially covered on the proximal end of the knee joint; each coil unit in the third group of unit coils is enclosed by an area which is overlapped with a part of the coil unit in the adjacent first group of unit coils respectively.

2. The knee joint radio frequency coil device according to claim 1, wherein the housing comprises an inner housing adjacent to the imaging site of the human body, and an outer housing mated with the inner housing to form a receiving space; the middle part of the inner shell is smaller in size, and the sizes of the inner shell in the directions towards the two ends are gradually increased.

3. The knee joint radio frequency coil device according to claim 1, wherein:

the first coil unit 1, the second coil unit 2, the eighth coil unit 8, the ninth coil unit 9, the twelfth coil unit 12, the thirteenth coil unit 13, and the sixteenth coil unit 16 are covered on the anterior side of the knee joint;

the third coil unit 3 and the seventh coil unit 7 are respectively covered on the left side and the right side of the knee joint;

the fourth coil unit 4, the fifth coil unit 5, the sixth coil unit 6, the tenth coil unit 10, the eleventh coil unit 11, the fourteenth coil unit 14 and the fifteenth coil unit 15 are covered on the posterior side of the knee joint.

4. The knee radio frequency coil device of claim 2, wherein the coil circuit is attached to the inner housing.

5. The knee radio frequency coil device of claim 2, wherein the inner and outer shells of the housing each comprise two separable portions.

6. The knee joint radio frequency coil device according to claim 5, wherein the third coil unit 3 and the seventh coil unit 7 each comprise two separable parts and are separately disposed in the two parts of the housing.

7. The knee radio frequency coil device of claim 1, wherein a spacing between adjacent coil units in the second and third sets of unit coils is greater than 10 millimeters and less than 30 millimeters.

8. The knee joint radio frequency coil device according to claim 1, wherein an area enclosed by the ninth coil unit 9 is partially overlapped with an area enclosed by the first, second, and third coil units 1, 2, and 3; the area enclosed by the tenth coil unit 10 is partially overlapped with the area enclosed by the third coil unit 3, the fourth coil unit 4, and the fifth coil unit 5; the area enclosed by the eleventh coil unit 11 is partially overlapped with the areas enclosed by the fifth coil unit 5, the sixth coil unit 6, and the seventh coil unit 7; and, the area enclosed by the twelfth coil unit 12 is partially overlapped with the areas enclosed by the seventh coil unit 7, the eighth coil unit 8, and the ninth coil unit 9.

9. The knee joint radio frequency coil device according to claim 1, wherein an area enclosed by the thirteenth coil unit 13 is partially overlapped with an area enclosed by the first, second, and third coil units 1, 2, and 3; the area enclosed by the fourteenth coil unit 14 is partially overlapped with the area enclosed by the third coil unit 3, the fourth coil unit 4, and the fifth coil unit 5; the area enclosed by the fifteenth coil unit 15 is partially overlapped with the areas enclosed by the fifth coil unit 5, the sixth coil unit 6, and the seventh coil unit 7; and, the area enclosed by the sixteenth coil unit 16 is partially overlapped with the areas enclosed by the seventh coil unit 7, the eighth coil unit 8, and the ninth coil unit 9.

10. A magnetic resonance imaging system comprising a knee joint radio frequency coil arrangement according to any one of claims 1 to 9.