Radio frequency coil assembly for a magnetic resonance imaging system

Abstract

The utility model relates to a kind of radio frequency coil components for magnetic resonance imaging system, including the coil array formed by the arrangement of multiple coil units in turn.Each coil unit includes flexible conductive wire that forms loop around. Coil array includes first area and second area, the loop of adjacent coil unit in two areas is all overlapped, but the overlap range or overlap proportion of adjacent coil unit in first area is less than the overlap range or overlap proportion of adjacent coil unit in second area, the coil unit density of first area is less than the coil unit density of second area.The radio frequency coil component can be applied to the imaging of different parts, such as chest coil, lower limb coil or neck-chest integrated coil, by the differential design of different area coil unit, the quality and efficiency of magnetic resonance imaging are improved.

Description

Technical Field

[0001] This utility model relates to magnetic resonance imaging systems, and more specifically to a radio frequency coil assembly for magnetic resonance imaging systems. Background Technology

[0002] Magnetic Resonance Imaging (MRI) is a non-invasive medical imaging technique widely used in clinical diagnosis and scientific research. In an MRI system, the radio frequency (RF) receiving coil is a key component for receiving the nuclear magnetic resonance signals emitted by human tissue, and its performance directly affects image quality. RF coils can be categorized into general-purpose RF coils and special-purpose RF coils based on their application. General-purpose RF coils can be used for imaging various parts of the body, such as the head, neck, chest, abdomen, and limbs. Special-purpose RF coils are used for specific body parts, environments, or fields, such as inner ear coils for precise scanning of the inner ear structure, carotid artery coils specifically for detecting carotid artery plaques, and special coils for ultra-high field environments above 5.0T.

[0003] RF receiving coils can be broadly categorized chronologically into birdcage coils, surface coils, phased array surface coils, and integrated phased array surface coils. Birdcage coils, surface coils, and phased array surface coils all use rigid materials. Birdcage coils primarily use rigid conductors, while surface coils and phased array surface coils use copper foil instead of rigid conductors. Integrated phased array surface coils often employ a semi-flexible structure, with flexible circuit boards used internally to enhance coil flexibility. While existing RF coils have reduced weight and improved patient comfort to some extent, the inherent non-flexibility of copper coil circuits and signal attenuation caused by adjacent coil units being close together remain insurmountable challenges.

[0004] In recent years, the industry has adopted novel fiber guide rings with adaptive characteristics for coil design, giving the coils greater flexibility. However, due to limitations in coil unit decoupling and the placement of internal electronic components, the coil units composed of fiber guide rings have a uniform overlap area, which is usually small and cannot well meet the imaging requirements of different human organs. In practical operation, when the total detector area is fixed, the more RF receiving channels there are, the smaller the coil unit size becomes. However, a smaller coil size reduces the penetration depth. In other words, it is difficult to arrange large-sized coil units within a limited area.

[0005] Therefore, there is an urgent need for a new type of radio frequency coil assembly to solve the problem of mutual constraints between the number, size, and overlapping area of ​​coil units when the coverage area of ​​local coils in various parts is relatively fixed, to balance the contradiction between penetration depth and coil size, and to meet the imaging needs of different organs. Utility Model Content

[0006] To address the technical problem that existing magnetic resonance coils cannot adequately meet the imaging needs of different organs, this invention provides a radio frequency coil assembly for a magnetic resonance imaging system, achieving a balance between penetration depth and coil size.

[0007] In a first aspect, the present invention provides a radio frequency coil assembly for a magnetic resonance imaging system, comprising multiple coil units arranged sequentially to form a coil array; each coil unit includes a flexible conductive wire forming a loop; the coil array includes a first region and a second region; the loops of at least two adjacent coil units overlap in the first region; the loops of at least two adjacent coil units overlap in the second region; the overlap range of adjacent coil units in the first region is smaller than the overlap range of adjacent coil units in the second region, and the coil unit density in the first region is smaller than the coil unit density in the second region.

[0008] In one embodiment, the radio frequency coil assembly is a chest coil, the second region covers the heart, the first region is the peripheral region of the coil array, and the second region is the central region of the coil array.

[0009] In one embodiment, the RF coil assembly further includes coupling electronics, which include at least a preamplifier; at least one coil unit is connected to a transmission line that extends beyond the first region or the coil array to enable connection between the coil unit and the coupling electronics.

[0010] In one embodiment, the coil array extends along both the X and Y directions; the coil units in the first region and the coil units in the second region are aligned only along the X direction; or,

[0011] The coil units in the first region and the coil units in the second region are aligned along the X and Y directions.

[0012] Secondly, the present invention provides a radio frequency coil assembly for a magnetic resonance imaging system, comprising: a plurality of coil units arranged sequentially to form a coil array; each coil unit includes a flexible conductive wire forming a loop; the coil array includes a first region and a second region; the loops of at least two adjacent coil units overlap in the first region; the loops of at least two adjacent coil units overlap in the second region; the overlap ratio of adjacent coil units in the first region is less than the overlap ratio of adjacent coil units in the second region, and the coil unit density in the first region is less than the coil unit density in the second region.

[0013] In one embodiment, the radio frequency coil assembly is a lower limb coil, with a first region covering the thigh region and a second region covering the calf region; the coil unit loop size of the first region is larger than the coil unit loop size of the second region.

[0014] In one embodiment, the radio frequency coil assembly is a cervicothoracic integrated coil, with a first region covering the clavicle region and the armpit region, and a second region covering the neck region;

[0015] Alternatively, the first region corresponds to the spinal region, and the second region covers the cervical region.

[0016] In one embodiment, the RF coil assembly further includes coupling electronics, which include at least a preamplifier; at least one coil unit is connected to a transmission line that extends outside the coil array to enable connection between the coil unit and the coupling electronics.

[0017] In one embodiment, the radio frequency coil assembly is a chest coil, with a first region corresponding to the lung region and a second region covering the heart.

[0018] In one embodiment, the coil unit loop sizes of the first region and the second region are the same.

[0019] In one embodiment, the radio frequency coil assembly further includes a flexible carrier that carries the coil array; the flexible carrier can be wound to wrap around the area to be detected.

[0020] In one embodiment, the RF coil assembly further includes coupling electronics, which include at least a preamplifier; at least one coil unit is connected to a transmission line that extends beyond the first region or the coil array to enable connection between the coil unit and the coupling electronics.

[0021] The beneficial effects of this invention are as follows: the coil unit includes flexible conductive wires that form loops, allowing the coil array in the coil assembly to maintain its thin and flexible characteristics; the loops of at least two adjacent coil units overlap in the first region and at least two adjacent coil units overlap in the second region, and the overlap range of adjacent coil units in the first region is smaller than that in the second region, and the coil unit density in the first region is smaller than that in the second region. That is, by changing the overlap range of adjacent coil units, the coil array can locally form a high density, so that the high-density area with more coil units corresponds to the organ of greater clinical interest, effectively improving the image quality of the area; increasing the overlap range of adjacent coil units in the high-density area ensures the penetration depth of the coil, while improving the acceleration capability of the coil and shortening the scanning time; the high-density area can be allocated to different positions as needed according to organ type and imaging requirements, maximizing the utilization of all coil units. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the coil array distribution of radio frequency receiving coils in the prior art;

[0023] Figure 2 This is a schematic diagram of the coil array distribution of a radio frequency coil assembly for a magnetic resonance imaging system according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the coil array distribution of a radio frequency coil assembly for a magnetic resonance imaging system according to another embodiment of the present invention;

[0025] Figure 4 This is a partial perspective view of the radio frequency coil assembly with integrated coupling electronic devices according to this utility model;

[0026] Figure 5 This is a partial perspective view of the radio frequency coil assembly separated from the coupled electronic device of this utility model;

[0027] Figure 6 A perspective view of the radio frequency coil assembly of this utility model applied to a chest scan;

[0028] Figure 7 This is a schematic diagram of the coil array distribution of a radio frequency coil assembly for a magnetic resonance imaging system according to another embodiment of the present invention;

[0029] Figure 8 This is a schematic diagram of the unfolded structure of the radio frequency coil assembly of this utility model applied to abdominal scanning;

[0030] Figure 9 This is a schematic diagram of the wound structure of the radio frequency coil assembly used in abdominal scanning according to the present invention.

[0031] In the attached image:

[0032] 10 - First coil unit; 20 - Second coil unit; 30 - Coupled electronic device; 40 - Transmission line; 50 - Accessory; 60 - Polyester fiber fabric. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0034] Existing RF receiver coil designs often revolve around several key parameters: the number of coil units (channels), the size of the coil units, and the overlap area of ​​the coil units. These parameters often determine the final performance of the coil and thus affect image quality. This is especially true for flexible coil designs, where the coil units are typically arranged in an array. For example... Figure 1 The diagram shows a schematic of the coil array distribution of a prior art radio frequency (RF) receiving coil, with a uniform overlap area between the coil units. Due to limitations in coil unit decoupling and internal component placement, the overlap area of ​​the coil units cannot be too large. Under the premise that the coverage area of ​​the RF receiving coil at each detection location is relatively fixed, the number, size, and overlap area of ​​the coil units will restrict each other: if you want to increase the number of channels to improve acceleration and reduce scanning time, with a fixed coverage area, the more channels the RF receiving coil has, the smaller the size of the coil unit will be, but this will reduce the penetration depth of the coil unit. That is, under the premise of limited area, it is difficult to accommodate taller, larger units.

[0035] This invention relates to a radio frequency (RF) coil assembly for a magnetic resonance imaging (MRI) system. Used as a receiving coil, it can increase the density of local coil units and the number of channels in the RF coil assembly according to the imaging requirements of different body parts, thereby improving the image quality or accelerating the detection of the corresponding local area. The RF coil assembly comprises multiple coil units, each serving as a receiving channel, arranged sequentially to form a coil array. Each coil unit includes a flexible conductive wire forming a loop. The coil array can be divided into different regions, based on the overlap range or overlap ratio of adjacent coil units, resulting in high-density and low-density regions within the same array. The coil array is divided into a region of interest (ROI) and its periphery based on whether the overlap range of adjacent coil units exceeds a set coverage area. The overlap range of adjacent coil units is the area covered by the loop of the flexible conductive wire in the overlapping region. The overlap ratio of adjacent coil units is the ratio of the area covered by the loop of the flexible conductive wire in the overlapping region to the area covered by the current loop of the flexible conductive wire. The overlap ratio of adjacent coil units can be any value between 0.1 and 0.8, such as 1 / 5, 1 / 3, 1 / 2, 3 / 5, 2 / 3, etc.

[0036] like Figure 2The diagram shown is a schematic representation of the coil array distribution of a radio frequency coil assembly for a magnetic resonance imaging system according to an embodiment of the present invention. The radio frequency coil assembly includes multiple coil units arranged sequentially to form a coil array with varying densities. The coil array extends along the X and Y directions. Each coil unit includes a flexible conductive wire that forms a loop. The shape of a single coil unit can be triangular, square, pentagonal, hexagonal, octagonal, dodecagonal, annular, saddle-shaped, butterfly-shaped, etc. Loops of adjacent coil units overlap in the first region, and similarly in the second region. The overlap angle of adjacent coil unit loops in the first and second regions is 45 degrees, 60 degrees, 75 degrees, or 90 degrees.

[0037] In this embodiment, the loop shape of the coil unit is circular. Based on the density of the coil units, the coil units of the coil array can be classified into a first coil unit 10 and a second coil unit 20. The first coil unit 10 and the second coil unit 20 have the same size. The first coil unit 10 is distributed in the first region, and the second coil unit 20 is distributed in the second region. The coil units in the first region and the coil units in the second region can be aligned only along the X direction. Correspondingly, the loop overlap angle of adjacent coil units in the first region and the second region is not 90 degrees. Alternatively, the coil units in the first region and the coil units in the second region can be aligned along both the X and Y directions. Correspondingly, the loop overlap angle of adjacent coil units in the first region and the second region is 90 degrees.

[0038] The first region is the outer perimeter of the coil array, specifically the four edges, while the second region is the central or inner region of the coil array. The density of the first coil unit 10 in the first region is less than the density of the second coil unit 20 in the second region. This design allows the RF coil assembly to provide different signal receiving sensitivities in different regions, thereby adapting to the imaging needs of different body parts. It should be noted that the different lines in this embodiment are only for better distinguishing the first coil unit 10 and the second coil unit 20, and the thickness of the lines is not directly related to the diameter of the flexible conductive wires of the first coil unit 10 and the second coil unit 20.

[0039] The coil units in the first region and the coil units in the second region can be aligned only along the X direction. In this embodiment, the first coil unit 10 and the second coil unit 20 form a coil array along the X and C directions, where the C direction is located between the X and Y directions (X is perpendicular to Y), and the angle between the C and X directions is 60 degrees, meaning the overlap angle of the loops of adjacent coil units is 60 degrees. Both the first coil unit 10 and the second coil unit 20 in the coil array overlap with adjacent coil units. Along the X direction, adjacent first coil units 10 overlap within a range of S1; adjacent second coil units 20 overlap within a range of S3, where S3 > S1. Along the C direction, adjacent loops of adjacent first coil units 10 overlap within a range of S2 in the first region; adjacent loops of adjacent second coil units 20 overlap within a range of S4, where S4 > S2. In the boundary region between the first and second regions, the first coil unit 10 and the second coil unit 20 also overlap. Along direction C, the loop overlap range of the first coil unit 10 and the second coil unit 20 is S6, which can be set to be equal to or greater than S4. Along other directions (at a 90-degree angle to direction C), the loop overlap range of the first coil unit 10 and the second coil unit 20 is S5, and S5 < S2. Of course, the loop overlap range of the first coil unit 10 and the second coil unit 20 can also be set to other values, depending on the degree of coupling between the two.

[0040] This invention does not limit the size of the first coil unit 10 and the second coil unit 20. In other embodiments, the size of the first coil unit 10 may be larger than the size of the second coil unit 20. That is, a larger size first coil unit 10 is provided in the surrounding edge area, and a relatively smaller size second coil unit 20 is provided in the central or inner area, which is beneficial to forming ultra-high receiving sensitivity in the central area.

[0041] like Figure 3 The diagram shown is a schematic representation of the coil array distribution of a radio frequency coil assembly for a magnetic resonance imaging system according to another embodiment of the present invention. The loop shape of the coil unit is circular. Based on the different density distributions of the coil units, the coil units of the coil array can be classified into a first coil unit 10 and a second coil unit 20. The first coil unit 10 and the second coil unit 20 have the same size. Specifically, the first coil unit 10 is distributed in a first region; the second coil unit 20 is distributed in a second region, and the distribution density of the first coil unit 10 is less than that of the second coil unit 20. The first region is the outer periphery of the coil array, specifically the four edges, and the second region is the central or inner region of the coil array. The central or inner region typically corresponds to the organ or tissue of interest, while the four edges represent the outer periphery of the organ of interest.

[0042] The coil units in the first region and the coil units in the second region are aligned along the X and Y directions. The first coil unit 10 and the second coil unit 20 form a coil array along the X and Y directions, meaning the overlap angle of adjacent coil unit loops is 90 degrees. The first coil unit 10 and the second coil unit 20 in the coil array overlap with adjacent coil units. Along the X direction, adjacent first coil units 10 overlap within a range of S1; adjacent second coil units 20 overlap within a range of S3, where S3 > S1. Along the Y direction, adjacent loops of the first coil units 10 overlap within a range of S2 in the first region; adjacent loops of the second coil units 20 overlap within a range of S4, where S4 > S2. In the boundary region between the first and second regions, the first coil unit 10 and the second coil unit 20 also overlap. The loop overlap range of the first coil unit 10 and the second coil unit 20 along the Y direction is S6, which can be set to be equal to S4. Along the diagonal direction (the direction between X and Y), the loop overlap range of the first coil unit 10 and the second coil unit 20 is S5. S5 is set according to the degree of coupling between the two; in this embodiment, based on the degree of coupling between two diagonally adjacent coil units, S5 is set to be less than S2.

[0043] like Figure 4 As shown, this utility model is as follows Figure 3 The partial perspective view of the RF coil assembly shown indicates that the RF coil assembly also includes a coupling electronics 30, which is disposed within the loop formed by the second coil units 20, i.e., the coupling electronics 30 is integrated with the coil array of the second coil units 20. The coupling electronics 30 may include one or more combinations of decoupling circuits, impedance inverter circuits, preamplifiers, and filters, and is disposed on a printed circuit board (PCB). Each second coil unit 20 is distributed in a one-to-one correspondence with the coupling electronics 30, avoiding the formation of large protrusions in the detection area of ​​the coil array.

[0044] like Figure 5 As shown, this utility model is as follows Figure 3Another partial perspective view of the RF coil assembly shown illustrates that the RF coil assembly also includes coupling electronics 30 disposed outside the loop formed by the second coil unit 20, for example, disposed within the loop of the first coil unit 10 or completely outside the entire coil array. The second coil unit 20 is connected to a transmission line 40, which extends to the first region or outside the coil array to achieve the connection between the coil unit and the coupling electronics 30. In this embodiment, the flexible conductive wire constituting the second coil unit 20 is composed of a coaxial line, which includes an inner core layer and a shielding layer disposed outside the inner core layer. The inner core layer is continuously and uninterruptedly wound, while the shielding layer has discontinuities. The discontinuities in the shielding layer act as a tuning capacitor, and a dielectric material can be filled between the inner core layer and the shielding layer to achieve resonance of the flexible conductive wire. One end of the transmission line 40 is connected to the flexible conductive wire, and the other end of the transmission line 40 extends out of the second region. The shielding layer is grounded at the port of the flexible conductive wire, and the inner core layer at the port of the flexible conductive wire is directly connected to the core wire of the coaxial transmission line of the transmission line 40.

[0045] The transmission line 40 extends outward from the other end of the second region and is externally coupled to the electronic device 30. In this embodiment, the electronic device 30 is a preamplifier that does not require a matching circuit. The amplifier is located outside the coil array of the RF coil assembly, that is, the amplifier 603 is located outside the flexible carrier, further saving space on the flexible carrier and improving the flexibility of the RF coil assembly. This design can reduce signal loss between the coil unit and the preamplifier, improving the overall signal reception quality. Specifically, the transmission line 40 can transmit the magnetic resonance signal received by the second coil unit 20 to the electronic device 30. Furthermore, the transmission line 40 achieves impedance matching between the second coil unit 20 and the preamplifier to improve the signal-to-noise ratio of the magnetic resonance signal.

[0046] In some embodiments, impedance matching can be achieved by designing the physical characteristics of transmission line 40 so that transmission line 120 has a characteristic impedance. The impedance of the second coil unit 20 serves as the input impedance, and the load serves as the output impedance. If both the input and output impedances are complex numbers, impedance matching between the second coil unit 20 and the load can be achieved when the real parts of the input and output impedances are equal and their imaginary parts are opposite. In some embodiments, impedance matching between the second coil unit 20 and the preamplifier can be achieved when the real part of the input impedance of the second coil unit 20 is equal to the real part of the output impedance of the preamplifier and their imaginary parts are opposite.

[0047] In some embodiments, the length of the transmission line 40 can be varied according to the wavelength of the magnetic resonance signal received by the second coil unit 20, enabling impedance matching of the transmission line 40. The length of the transmission line 40 can be a weighted sum of wavelength length coefficients used by the transmission line 40 for signal transmission. For example, in some embodiments, the length of the transmission line 40 can be an odd multiple of a quarter wavelength, where the wavelength can be the wavelength of the magnetic resonance signal transmitted in the transmission line 40.

[0048] The flexible carrier supporting the second coil unit 20 can be wound to wrap the area to be tested. It consists of three layers: the outer layer is generally made of PU leather, which has the advantages of being lightweight, aging-resistant, wear-resistant, dense, and non-image-forming; the inner filling is generally made of felt, which provides fire resistance, heat insulation, and improved comfort; the middle layer is made of a softer non-woven fabric, suitable for parts that need to be bent and deformed. Of course, a stiffer lining cloth can also be used for the middle layer, which can be used for parts that need to be shaped.

[0049] Similarly, a coupling electronic device 30 can also be connected to the first coil unit 10, and the coupling electronic device 30 is connected via a method similar to that described above. Figure 4 Connect the first coil unit 10 in the same manner, or in a manner similar to that described above. Figure 5 The first coil unit 10 is connected in the same manner. When the corresponding coupling electronics 30 is connected to the first coil unit 10 via the transmission line 40, the other end of the transmission line 40 extending beyond the entire coil array (extending beyond the first region) is externally coupled to the coupling electronics 30. The amplifier 603 is disposed outside the flexible carrier, further saving space on the flexible carrier and improving the flexibility of the RF coil assembly. This design can reduce signal loss between the coil unit and the preamplifier, improving the overall signal reception quality.

[0050] like Figure 6 The image shows a perspective view of the radio frequency coil assembly applied in a chest scan. The radio frequency coil assembly is a chest coil, with the second region covering the heart. Both the first coil unit 10 and the second coil unit 20 have a diameter of 5 cm. Since the heart is a key area of ​​focus in chest imaging and requires higher image quality, increasing the overlap and density of the coil units in the second region improves signal reception sensitivity and signal-to-noise ratio, resulting in a clearer image of the heart. The first region covers the area from the scapula to the clavicle, the axilla, the upper chest boundary, and the rib edges; the second region covers the heart, liver, and both lungs, centered on the heart. Along the left-right direction (corresponding to the X-axis), the overlap of adjacent first coil units 10 in the first region is approximately 3.9 cm. 2 In the second region, the overlap range of adjacent second coil units 20 is approximately 6.5 cm. 2Similarly, along the patient's longitudinal direction (corresponding to the Y direction), in the first region, the overlap range of adjacent first coil units 10 is approximately 3.9 cm. 2 In the second region, the overlap range of adjacent second coil units 20 is approximately 6.5 cm. 2 This differentiated overlapping design allows the RF coil assembly to provide higher signal reception capabilities for the cardiac region while maintaining overall sensitivity.

[0051] Please refer to the attached document. Figure 6 The overall size of the radio frequency coil assembly is suitable for covering an adult chest, with a length of approximately 40 cm and a width of approximately 35 cm. The coil array contains a total of 32 coil units, forming a 32-channel chest coil. The first region contains 16 first coil units 10, and the second region contains 16 second coil units 20 in a 4×4 array. The center-to-center spacing of the first coil units 10 in the first region is greater than that of the second coil units 20 in the second region, meaning the distribution of the second coil units 20 is denser. Compared to a 25-channel chest coil formed by arranging the first coil units 10 in regular rows and columns, this 32-channel chest coil has more receiving channels. In practical applications, the radio frequency coil assembly is placed on the patient's chest, with the second region aligned with the heart. When the magnetic resonance imaging system is operating, the coil units receive radio frequency signals from the patient's body and transmit them to a preamplifier for amplification via transmission lines. Due to the larger coil unit overlap and higher coil unit density in the second region, higher signal reception sensitivity is provided, resulting in clearer cardiac images.

[0052] like Figure 7 The diagram shows a schematic representation of the coil array distribution of a radio frequency coil assembly for a magnetic resonance imaging system according to another embodiment of the present invention. The radio frequency coil assembly includes multiple coil units arranged sequentially to form a coil array. Each coil unit includes a flexible conductive wire that forms a loop. The coil array includes a first region and a second region. In the first region, the loops of at least two adjacent coil units overlap, and in the second region, the loops of at least two adjacent coil units also overlap. The overlap ratio of adjacent coil units in the first region is smaller than that in the second region.

[0053] In this embodiment, the radio frequency coil assembly is a lower limb coil, with a first region covering the thigh area and a second region covering the calf area. A first coil unit 10 is arranged in the first region, and a second coil unit 20 is arranged in the second region. The loop size of the first coil unit 10 is larger than the loop size of the second coil unit 20. This design takes into account the anatomical characteristics of the human lower limb; the cross-sectional area of ​​the thigh is larger than that of the calf, thus requiring a larger coil unit for coverage. Specifically, the loop diameter of the coil unit in the first region is 8 cm, and the loop diameter of the coil unit in the second region is 5 cm. The first region contains 5 first coil units 10, and the second region contains 7 second coil units. Along the left-right direction (X direction) of the patient, the overlap ratio of adjacent coil units in the first region is approximately 25% of the area enclosed by the corresponding loop, while the overlap ratio of adjacent coil units in the second region is approximately 35% of the area enclosed by the corresponding loop.

[0054] Between the first and second regions lies a third region containing six coil units, each with a loop diameter of 6.5 cm. Along the patient's left-right direction (corresponding to the X-direction), the overlap ratio of adjacent coil units in the third region is approximately 30% of the area enclosed by the corresponding loop. That is, along the patient's longitudinal direction, the radiofrequency coil assembly forms a multi-level structure: the density of the coil units decreases abruptly, the size of the coil units increases abruptly, and the overlap ratio of adjacent coil units decreases abruptly, thereby adapting to the gradual changes in the size of the patient's limb and achieving tight wrapping of the entire limb.

[0055] In practical applications, the radio frequency coil assembly is placed on the patient's lower limb, with the first region aligned with the thigh and the second region aligned with the calf. When the magnetic resonance imaging system is operating, the coil unit receives radio frequency signals from within the patient's body and transmits them to a preamplifier for amplification via a transmission line. Because the second region has a larger coil unit overlap ratio and a smaller coil unit loop size, it provides higher signal reception sensitivity, resulting in clearer lower limb images.

[0056] like Figure 8The diagram shows the unfolded structure of the radio frequency coil assembly used in abdominal scanning according to this invention. The radio frequency coil assembly includes a flexible carrier and a coil array supported by the flexible carrier. The coil array includes multiple coil units extending along the X and Y directions, each coil unit corresponding to a receiving channel. The flexible carrier can be wound to wrap around the area to be detected. Based on the density distribution of the coil units, the coil units of the coil array can be classified into first coil units 10 and second coil units 20. The first coil units 10 and second coil units 20 are of the same size. The first coil units 10 are distributed in the edge region; the second coil units 20 are distributed in the inner region (shown by dashed lines in the diagram). In the upper and lower edge regions, six first coil units 10 in each row are regularly arranged along the X direction; in the left and right edge regions, three first coil units 10 in each column are regularly arranged along the Y direction. Thus, 14 receiving channels are formed in the edge region. In the inner region, ten second coil units 20 are evenly arranged but form an irregular array. Compared to the traditional 18-channel abdominal receiving coil with a regular 6×3 arrangement, the radio frequency coil assembly used in this embodiment of the invention for abdominal scanning has a total of 24 channels, forming a high-density receiving channel in the region corresponding to the organ of interest, thereby improving the sensitivity of the receiving coil.

[0057] An accessory 50 is also provided on the flexible carrier of the RF coil assembly. The accessory 50 may have an accessory connector, which can be connected to the transmission line 40. In this embodiment, the accessory 50 is located in the adjacent area of ​​the first coil unit 10 and the second coil unit 20. The accessory connector of the accessory 50 may be a socket. The RF coil assembly has a total of 24 channels connected to their respective transmission lines 40 through the accessory, and all transmission lines 40 converge and connect to an external preamplifier.

[0058] The flexible carrier can be a plastic material with good flexibility and elasticity, such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), or polyurethane (PU); it can also be a rubber-based material; a woven material such as canvas, cotton fabric, or polyester fiber fabric; or a natural material such as animal fur. The flexible conductive wire can be bent arbitrarily with the flexible carrier without affecting its electrical properties. The radio frequency coil assembly can be placed on the patient's bed to receive magnetic resonance signals from the spine and neck; it can also be placed on the patient's body surface to receive magnetic resonance signals from the abdomen and chest. Figure 9 The diagram shows the structure of the radio frequency coil assembly in the coiled state of the present invention applied to abdominal scanning. The flexible carrier is selected as polyester fiber fabric 60, which can be coiled (in the direction of the arrow in the figure) to tightly wrap the patient's abdomen; and, because of the use of flexible carrier and flexible conductive wire, the patient's pressure is reduced, which can effectively alleviate the patient's tension and anxiety, and greatly improve the patient's comfort during the examination.

[0059] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0060] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A radio frequency coil assembly for a magnetic resonance imaging system, characterized in that, The radio frequency coil assembly includes: Multiple coil units are arranged sequentially to form a coil array; Each coil unit includes a flexible conductive wire that forms a loop; The coil array includes a first region and a second region; In the first region, at least two adjacent coil units have overlapping loops; In the second region, at least two adjacent coil units have overlapping loops; The overlap range of adjacent coil units in the first region is smaller than the overlap range of adjacent coil units in the second region; The coil unit density in the first region is less than that in the second region.

2. The radio frequency coil assembly according to claim 1, characterized in that, The radio frequency coil assembly is a chest coil, the second region covers the heart, the first region is the peripheral region of the coil array, and the second region is the central region of the coil array.

3. The radio frequency coil assembly according to claim 2, characterized in that, The radio frequency coil assembly also includes coupling electronics, which include at least a preamplifier; At least one of the coil units is connected to a transmission line that extends beyond the first region or the coil array to enable the connection between the coil unit and the coupled electronics.

4. The radio frequency coil assembly according to claim 2 or 3, characterized in that, The coil array extends along the X and Y directions; The coil units in the first region and the coil units in the second region are aligned only along the X direction; or, The coil units in the first region and the coil units in the second region are aligned along the X direction and the Y direction, respectively.

5. A radio frequency coil assembly for a magnetic resonance imaging system, characterized in that, The radio frequency coil assembly includes: Multiple coil units are arranged sequentially to form a coil array; Each coil unit includes a flexible conductive wire that forms a loop; The coil array includes a first region and a second region; In the first region, at least two adjacent coil units have overlapping loops; In the second region, at least two adjacent coil units have overlapping loops; The overlap ratio of adjacent coil units in the first region is smaller than that of adjacent coil units in the second region; The coil unit density in the first region is less than that in the second region.

6. The radio frequency coil assembly according to claim 5, characterized in that, The radio frequency coil assembly is a lower limb coil, with the first region covering the thigh region and the second region covering the calf region; The loop size of the coil unit in the first region is larger than that in the second region.

7. The radio frequency coil assembly according to claim 5, characterized in that, The radio frequency coil assembly is a neck-chest integrated coil, with the first region covering the clavicle region and the armpit region, and the second region covering the neck region; Alternatively, the first region corresponds to the spinal region, and the second region covers the neck region.

8. The radio frequency coil assembly according to claim 6, characterized in that, The radio frequency coil assembly is a chest coil, with the first region corresponding to the lung region and the second region covering the heart; The coil unit loop dimensions are the same in the first region and the second region.

9. The radio frequency coil assembly according to any one of claims 6-8, characterized in that, The radio frequency coil assembly also includes a flexible carrier that supports the coil array. The flexible carrier can be rolled up to wrap around the area to be tested.

10. The radio frequency coil assembly according to any one of claims 6-8, characterized in that, The radio frequency coil assembly also includes coupling electronics, which include at least a preamplifier; At least one of the coil units is connected to a transmission line that extends outside the coil array to enable the connection between the coil unit and the coupled electronics.

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