Magnetic resonance coil device

Abstract

The application relates to the technical field of nuclear magnetic resonance imaging, in particular to a magnetic resonance coil device, which comprises: a base used for being detachably fixed to a magnetic resonance examination bed and configured to be height-adjustable; a shell defining an examination cavity with an opening part facing a horizontal direction and supported on the base in a manner capable of moving along the horizontal direction, wherein the examination cavity is used for receiving a subject via the opening part; a support seat detachably supported on the base and having a part thereof extended into the examination cavity via the opening part, the support seat being used for supporting the subject; and a radio frequency coil installed in a thickness space between an inner surface and an outer surface of the shell and used for emitting a radio frequency signal to the subject and / or receiving a magnetic resonance signal from the subject.

Description

Technical Field

[0001] This application relates to the field of magnetic resonance imaging technology, and more particularly to a magnetic resonance coil device. Background Technology

[0002] Magnetic resonance coil devices are an important component of magnetic resonance imaging (MRI) systems, enabling them to receive magnetic resonance signals from the subject being examined.

[0003] Magnetic resonance coil (MRC) devices vary in construction depending on the object being examined. Therefore, MRC devices are generally not integrated with the examination table at the main magnet of the MRI system, but are designed to be easily detached and replaced. Historically, MRC devices had to be manufactured to dimensions (e.g., height) that matched the examination table and main magnet to which they would be used. This ensured that, after being attached to the examination table, the examination cavity defined by the MRC device was precisely centered within the cavity of the main magnet, facilitating the acquisition of high-quality MRI images. However, such MRC devices were only compatible with specific examination tables and main magnets, exhibiting poor compatibility with other types of examination tables and main magnets. Summary of the Invention

[0004] In view of this, this application proposes a magnetic resonance coil device.

[0005] The magnetic resonance coil device proposed in this application includes:

[0006] The base is designed for detachable attachment to the MRI examination table and is configured as a height-adjustable structure.

[0007] A housing defining an inspection cavity having an opening facing a horizontal direction, and supported on a base in a manner movable along said horizontal direction, wherein the inspection cavity is used to receive an object to be inspected via said opening;

[0008] A support base is detachably supported on the base, and a portion of the support base extends into the inspection chamber through the opening; the support base is used to support the object being inspected.

[0009] A radio frequency coil is installed in the thickness space between the inner and outer surfaces of the housing for transmitting radio frequency signals to the subject and / or receiving magnetic resonance signals from the subject.

[0010] In some possible implementations, the object under inspection is completely moved out of the inspection chamber via the opening by moving the housing relative to the base in the horizontal direction.

[0011] In some possible implementations, the object to be examined is the head of a human body, and the support includes an arc-shaped plate that extends into the examination cavity and is used to support the head.

[0012] In some possible implementations, the support base includes:

[0013] The first part is detachably connected to the base outside the inspection cavity and has an upwardly extending insert with a threaded hole.

[0014] The second part is for supporting the object under inspection and has a downward-opening slot that receives the insert in a manner that allows it to move along the vertical direction;

[0015] The locking bolt engages with the threaded hole and has a locked state and a released state by being rotated. In the released state, the second part is allowed to move relative to the first part in the vertical direction. In the locked state, the second part and the first part are fixed to each other in the vertical direction.

[0016] In some possible implementations, the base is configured as a height-adjustable lifting structure.

[0017] In some possible implementations, the base includes:

[0018] The lower seat is detachably fixed to the magnetic resonance examination table;

[0019] Lifting mechanism;

[0020] An upper seat is connected to the upper side of the lower seat via the lifting mechanism, wherein the housing is connected to the upper seat, and the lifting mechanism can be operated to drive the upper seat to rise or fall relative to the lower seat.

[0021] In some possible implementations, the upper body has two opposite sides with linear guides extending along the horizontal direction, and the bottom of the housing has a slider connected to the linear guides in a manner that allows it to move along the horizontal direction.

[0022] In some possible implementations, the lifting mechanism includes:

[0023] A pair of sliding grooves are formed on the lower body and extend along the horizontal direction, and are spaced apart from each other in a horizontally spaced direction perpendicular to the horizontal direction;

[0024] A pair of upper sliding grooves are formed on the upper seat and extend along the horizontal direction, and are spaced apart from each other in the spaced direction;

[0025] A pair of first links are connected to each other in a cross manner at the middle part, in a manner that allows them to rotate about the spaced-out direction. The first end of the first link is rotatably connected to the lower seat, and the second end is slidably and rotatably connected to the first upper slide groove of the pair of upper slide grooves. The first end of the second link is slidably and rotatably connected to the first lower slide groove of the pair of lower slide grooves, and the second end is rotatably connected to the upper seat.

[0026] A pair of second links are connected to each other in a cross manner at the middle part, in a manner that allows them to rotate about the spaced-out direction. The first end of the first second link is rotatably connected to the lower seat body, and the second end is slidably and rotatably connected to the second upper slide groove in the pair of upper slide grooves. The first end of the second second link is slidably and rotatably connected to the first lower slide groove in the pair of lower slide grooves, and the first end is rotatably connected to the upper seat body.

[0027] The third link extends along the spacing direction and connects the second end of the first link and the second end of the first second link;

[0028] An adjusting screw extends along the horizontal direction and is screwed into the upper seat. One end is provided with a handwheel, and the other end is rotatably but not movable along the horizontal direction and connected to the third link. The adjusting screw is configured to drive the third link to move along the horizontal direction by manually rotating the handwheel, thereby driving the upper seat to rise and fall relative to the lower seat.

[0029] In some possible implementations, in the horizontal direction, the handwheel is positioned on the side of the inspection chamber opposite to the opening.

[0030] In some possible implementations, the opposite ends of the third link are slidably inserted into the pair of upper slots, and the second end of the first link and the second end of the first second connecting rod are rotatably connected to the third link.

[0031] In some possible implementations, the other end of the adjusting screw is connected to the third link via a connecting seat having a first hole through which the third link passes and a second hole for receiving the other end of the adjusting screw, the second end of the adjusting screw being rotatably but not movable in the horizontal direction connected to the second hole.

[0032] The magnetic resonance coil device provided in this application includes: a base for detachably fixing to a magnetic resonance examination table and configured with a height-adjustable structure; a housing defining an examination cavity having an opening facing a horizontal direction and supported on the base in a manner movable in the horizontal direction, wherein the examination cavity is used to receive a subject through the opening; a support seat detachably supported on the base, and a portion of the support seat extends into the examination cavity through the opening, the support seat being used to support the subject; and a radio frequency coil mounted in a thickness space between the inner and outer surfaces of the housing for transmitting radio frequency signals to the subject and / or receiving magnetic resonance signals from the subject. Therefore, in implementation, the height of the housing relative to the examination table can be changed by adjusting the height of the base, thereby positioning the examination cavity and radio frequency coil, positioned by the housing, at the center position of the main magnet associated with the examination table. Furthermore, the relative positions of the examination cavity and radio frequency coil with the subject can be changed by adjusting the position of the housing in the horizontal direction. Therefore, this magnetic resonance coil device has good adaptability to different MRI systems. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this application, and are not intended to limit this application.

[0034] Figure 1 This is a schematic diagram of the structure of the magnetic resonance coil device provided in the embodiments of this application.

[0035] Figure 2 yes Figure 1 A diagram from another perspective.

[0036] Figure 3 yes Figure 1 A diagram from another perspective.

[0037] Figure 4 yes Figure 1 A schematic diagram of the radio frequency coil of the magnetic resonance coil device shown.

[0038] Figure 5 yes Figure 4 A diagram from another perspective.

[0039] Figure 6 This is a schematic diagram of the circuit structure corresponding to one coil unit in the first coil array.

[0040] Figure 7 This is a schematic diagram of the circuit structure corresponding to one coil unit in the second coil array.

[0041] Figure 8This is the isolation curve between the second node and the third node obtained by testing when the first coil unit in the magnetic resonance coil device provided in this application is working in the receiving mode. The main magnetic field, namely the B0 field, is a 7.0T ultra-high magnetic field. Under the 7.0T ultra-high magnetic field, the Larmor frequency of the hydrogen nucleus is 297.2MHz.

[0042] Figure 9 The isolation curve between the second node and the third node is obtained by removing the first capacitor, the second capacitor and the third inductor of the first radio frequency transceiver circuit in the magnetic resonance coil device provided in this application embodiment, and when the first coil unit is working in receiving mode under an ultra-high magnetic field of 7.0T.

[0043] Figure 10 This application provides a magnetic resonance imaging (MRI) image of a subject's head obtained using the first coil array in the MRI coil apparatus provided in this embodiment, based on a Turbo Spin Echo (TSE) sequence and hydrogen nuclear magnetic resonance (NMR). The image features a repetition time of 7000 ms, an echo time of 66 ms, a flip angle of 120°, and a resolution of 1 × 1 × 2 mm. 3 .

[0044] Figure 11 This document describes a magnetic resonance imaging (MRI) image of a subject's head obtained using a first coil array in the MRI coil apparatus provided in this application. The image is based on a magnetization-prepared rapid acquisition gradient echo (MPRAGE) sequence and hydrogen nuclear magnetic resonance. The parameters are: repetition time = 2270 ms, echo time = 1.87 ms, reversal time = 900 ms, flip angle = 6°, and resolution = 1 × 1 × 1 mm. 3 .

[0045] Figure 12 To obtain a magnetic resonance image of a subject's head using the first coil array in the magnetic resonance coil device provided in this application, based on fluid-attenuated inversion recovery (FLAIR) and hydrogen nuclear magnetic resonance, wherein the repetition time = 9000 ms, echo time = 76 ms, inversion time = 2600 ms, flip angle = 120°, and resolution = 1×1×2 mm. 3 .

[0046] Figure 13This document describes how to obtain magnetic resonance images of a subject's head using a second coil array in the magnetic resonance coil device provided in this application. The images are based on a density-adapted 3D radial acquisition (DA-3D-RAD) sequence and sodium nuclear magnetic resonance. The parameters are: repetition time = 120 ms, echo time = 0.35 ms, flip angle = 90°, 5000 projections, and a resolution of 3×3×3 mm. 3 .

[0047] Figure 14 This is a schematic diagram of the structure of the magnetic resonance coil device provided in the embodiments of this application.

[0048] Figure 15 This is a structural block diagram of the magnetic resonance system provided in the embodiments of this application.

[0049] Explanation of reference numerals in the attached figures:

[0050] 1000-Magnetic Resonance System;

[0051] 100 - Magnetic resonance coil equipment, 200 - Transmitter, 300 - Receiver;

[0052] DR1 - Horizontal direction, DR2 - Vertical direction, DR3 - Separated direction;

[0053] 1-Base;

[0054] 2-Shell;

[0055] 3-RF coil;

[0056] 4-Lower seat body, 4a-Sliding groove;

[0057] 5-Upper seat, 5a-Upper slide groove, 5b-Through threaded hole, 5c-Linear guide rail;

[0058] 6- Lifting mechanism;

[0059] 7-First Link;

[0060] 8-Second link;

[0061] 9-Third link;

[0062] 10 - Fourth Link;

[0063] 11-Adjusting screw, 11a-Handwheel;

[0064] 12-Connector;

[0065] 13-Head support base, 13a-Arc-shaped plate;

[0066] 14-Small animal support;

[0067] 15-Part 1, 15a-Insertion Block;

[0068] 16 - Part Two, 16a - Slot;

[0069] 17-Locking bolt;

[0070] 18 - Inspection cavity, 18a - Opening;

[0071] 19 - Outer surface of the shell;

[0072] 20 - Inner surface of the shell;

[0073] 21 - First coil array;

[0074] 22 - Second coil array;

[0075] 23 - First coil unit;

[0076] 24 - Second coil unit;

[0077] 25 - First RF power divider;

[0078] 26 - First preamplifier;

[0079] 27 - Second RF power divider;

[0080] 28 - Second preamplifier;

[0081] 29-Baron;

[0082] 30-Slider;

[0083] 31-First RF transceiver circuit;

[0084] 32-Second RF transceiver circuit;

[0085] C0, C t - Tuning capacitor of the coil unit, C m - Matching capacitors for the coil unit;

[0086] n1 - First node, n2 - Second node, n3 - Third node, n4 - Bias voltage input node;

[0087] C1 - First capacitor, C2 - Second capacitor, C3 - Third capacitor, C4 - Fourth capacitor, C5 - Fifth capacitor, C6 - Sixth capacitor, C7 - Seventh capacitor;

[0088] D1 - First diode, D2 - Second diode, D3 - Third diode;

[0089] L1 - First inductor, L2 - Second inductor, L3 - Third inductor, L4 - Fourth inductor, L5 - Fifth inductor;

[0090] GND - Ground potential. Detailed Implementation

[0091] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the described embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. It is understood that, without conflict, some technical means of the various embodiments described herein can be substituted for or combined with each other.

[0092] In the description of this application, the terms "first," "second," etc., are used only to distinguish the described objects and have no sequential or technical meaning. Therefore, objects specified with "first," "second," etc., may explicitly or implicitly include one or more of those objects, and, for example, the term "first element" itself does not imply the existence of a "second element," nor does the term "second element" itself imply the existence of a "first element." Furthermore, words such as "a" or "one" do not indicate a quantity limitation, but rather indicate the presence of at least one, while "multiple" indicates not less than two.

[0093] In the description of this application, the terms "comprising" or "having" indicate the presence of the said features, numbers, operations, elements, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, numbers, operations, elements, and / or combinations thereof.

[0094] In the description of this application, if there are terms such as “configured as” or “constructed as”, they are generally interchangeable with “having the ability to”, “designed to”, “used for” or “capable”, depending on the context.

[0095] In the description of this application, references to "one embodiment" or "some embodiments" mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized.

[0096] Figures 1 to 3A magnetic resonance coil device 100 provided in an embodiment of this application is shown. The device 100 includes a base 1, a housing 2 supported by the base 1, and a radio frequency coil 3 installed in the housing 2.

[0097] The base 1 is configured as a height-adjustable lifting structure, comprising a lower base 4 detachably fixed to the MRI examination table, and an upper base 5 connected to the upper side of the lower base 4 via a lifting mechanism 6, wherein the lifting mechanism 6 can be operated to drive the upper base 5 to rise or fall relative to the lower base 4, i.e., relative to the MRI examination table. Furthermore, the upper base 5 has two opposite sides with linear guide rails 5c extending in the horizontal direction DR1.

[0098] The housing 2 is formed as a generally cylindrical shape, open at one end and closed at the other, thereby defining an examination cavity 18 inside for receiving the subject. The examination cavity 18 has an opening 18a facing the horizontal direction DR1. In this embodiment, the subject is the head of a human body. The housing 2 is connected to the linear guide rail 5c of the upper body 5 via a slider 30 provided at its bottom, which allows it to move along the horizontal direction DR1. A portion of the housing 2 extends into the gap between the arc plate 13a and the upper body 5, thus the arc plate 13a is received within the examination cavity 18 defined by the housing 2. As a result, the relative position of the housing 2 with respect to the arc plate 13a and, further, the subject's head can be adjusted by the sliding engagement of the slider 30 with the linear guide rail 5c. In addition, the slider 30 can be fixed to multiple positions on the linear guide rail 5c by means of fastening bolts (not shown), thereby stably maintaining the relative position of the radio frequency coil 3 inside the housing 2 with respect to the subject during imaging examination.

[0099] Please see Figure 4 and Figure 5 The radio frequency coil 3 includes a first coil array 21 and a second coil array 22, both of which are mounted inside the housing 2, specifically within the thickness space between the inner surface 2020 and the outer surface 19 of the housing. The inner surface 20 defines the boundary of the inspection cavity 18. The housing 2 can be opened to expose the first coil array 21 and the second coil array 22, facilitating maintenance. In practice, the first coil array 21 and the second coil array 22 can be installed into the inner housing with the housing 2 open, and then the housing 2 can be closed to conceal and protect them. The first coil array 21 and the second coil array 22 can also be referred to as a first magnetic resonance coil array and a second magnetic resonance coil array.

[0100] The first coil array 21 includes eight first coil units 23 arranged around the inspection cavity 18 and also around the aforementioned horizontal direction DR1. The second coil array 22 includes eight second coil units 24 arranged around the inspection cavity 18 and also around the aforementioned horizontal direction DR1. The first coil units 23 have a first resonant frequency corresponding to a hydrogen nucleus, and the second coil units 24 have a second resonant frequency corresponding to a sodium nucleus. That is, the resonant frequency of the first coil units 23 is the Larmor frequency of the hydrogen nucleus, and the resonant frequency of the second coil units 24 is the Larmor frequency of the sodium nucleus. At an ultra-high field strength of 7.0T, the Larmor frequency of the hydrogen nucleus is 297.2MHz. Therefore, it can be determined by... Figure 6 The tuning capacitor C of the first coil unit 23 t The capacitor is adjusted so that the resonance of the first coil unit 23 is at 297.2MHz, thereby enabling the device 100 to be applied to a 7.0T ultra-high field strength MRI system.

[0101] In this embodiment, eight first coil units 23 are arranged in a closed loop structure that surrounds the inspection cavity 18 on the entire circumference, and eight second coil units 24 are also arranged in a closed loop structure that surrounds the inspection cavity 18 on the entire circumference. The eight first coil units 23 are located on the outer periphery of the eight second coil units 24, and any two adjacent first coil units 23 partially overlap to decouple, and any two adjacent second coil units 24 partially overlap to decouple.

[0102] In this embodiment, both the first coil unit 23 and the second coil unit 24 are integrated transceiver coils. Therefore, in application, on one hand, the first coil array 21 can transmit a radio frequency signal at a first resonant frequency to the subject's head to generate a B1 field, thereby exciting the hydrogen nuclei within the subject's head to generate a magnetic resonance signal (or magnetic resonance radio frequency signal) at the first resonant frequency. The first coil unit 23 then receives the magnetic resonance signal from the hydrogen nuclei to obtain a magnetic resonance image of the subject's head based on the magnetic resonance effect of the hydrogen nuclei. On the other hand, the second coil array 22 can also transmit a radio frequency signal at a second resonant frequency to the subject's head to generate a B1 field, thereby exciting the sodium nuclei within the subject's head to generate a magnetic resonance signal at the second resonant frequency. The second coil unit 24 then receives the magnetic resonance signal from the sodium nuclei to obtain a magnetic resonance image of the subject's head based on the magnetic resonance effect of the sodium nuclei. Furthermore, in some embodiments, the magnetic resonance image based on hydrogen nuclei can be fused with the magnetic resonance image based on sodium nuclei to obtain a fused magnetic resonance image based on both hydrogen and sodium nuclei.

[0103] The lifting mechanism 6 of the base 1 includes a pair of lower sliding grooves 4a, a pair of upper sliding grooves 5a, a pair of first connecting rods 7, a pair of second connecting rods 8, a third connecting rod 9, a fourth connecting rod 10, and an adjusting screw 11.

[0104] A pair of sliding grooves 4a are formed on the lower body 4 and extend along the horizontal direction DR1, and the pair of sliding grooves 4a are spaced apart from each other in the horizontal separation direction DR3, which is perpendicular to the horizontal direction DR1.

[0105] A pair of upper slide grooves 5a are formed on the upper seat 5 and extend parallel to each other along the horizontal direction DR1, and the pair of upper slide grooves 5a are also spaced apart from each other in the spaced direction DR3.

[0106] A pair of first connecting rods 7 are cross-connected at their midpoint in a manner that allows them to rotate about a spaced-apart direction DR3. The first end of the first connecting rod is rotatably connected to the lower seat 4, and the second end is slidably and rotatably connected to the first upper slide groove 5a of a pair of upper slide grooves 5a. The first end of the second connecting rod 7 is slidably and rotatably connected to the first lower slide groove 4a of a pair of lower slide grooves 4a, and the second end is rotatably connected to the upper seat 5.

[0107] A pair of second connecting rods 8 are intersected at their midpoints in a manner that allows them to rotate about a spaced-apart direction DR3. The first end of the first second connecting rod is rotatably connected to the lower seat 4, and the second end is slidably and rotatably connected to the second upper slide groove 5a of a pair of upper slide grooves 5a. The first end of the second second connecting rod 8 is slidably and rotatably connected to the second lower slide groove 4a of a pair of lower slide grooves 4a, and the second end is rotatably connected to the upper seat 5. In this embodiment, each first connecting rod 7 and each second connecting rod 8 has the same length, and each lower slide groove 4a and each upper slide groove 5a has the same length.

[0108] The third link 9 extends along the separation direction DR3 and connects the second end of the first link 7 and the second end of the first connecting rod. Specifically, the opposite ends of the third link 9 are slidably inserted into a pair of upper sliding grooves 5a, and the second ends of the first link 7 and the second ends of the first connecting rod are rotatably but not movable along the separation direction DR3 connected to the opposite ends of the third link 9. In other words, the second ends of the first link 7 and the second ends of the first connecting rod are slidably and rotatably connected to a pair of upper sliding grooves 5a via the third link 9.

[0109] The fourth link 10 extends along the spaced direction DR3 and connects the first end of the second first link 7 and the first end of the second second connecting rod. Specifically, the opposite ends of the fourth link 10 are slidably inserted into a pair of sliding grooves 4a, and the first ends of the second first link 7 and the second second connecting rod are rotatably but not movable along the spaced direction DR3 connected to the opposite ends of the fourth link 10. In other words, the first ends of the second first link 7 and the second second connecting rod are slidably and rotatably connected to the pair of sliding grooves 4a via the fourth link 10.

[0110] The adjusting screw 11 extends horizontally along DR1 and engages with the through threaded hole 5b of the upper body 5. One end of the adjusting screw 11 is provided with a handwheel 11a, and the other end is rotatably connected to the third link 9, but not movable along the horizontal direction DR1. The adjusting screw 11 is configured to drive the third link 9 to move horizontally along DR1 by manually rotating the handwheel 11a, thereby driving the upper body 5 to rise and fall relative to the lower body 4.

[0111] In the horizontal direction DR1, the handwheel 11a is positioned on the side of the examination chamber 18 opposite to the opening 18a, which helps to spatially avoid the subject's body by adjusting the screw 11 and the handwheel 11a of the adjusting screw 11.

[0112] In this embodiment, the other end of the adjusting screw 11 is connected to the third link 9 via a connecting seat 12. The connecting seat 12 has a first hole through which the third link 9 passes and a second hole for receiving the other end of the adjusting screw 11. The other end of the adjusting screw 11 is rotatably engaged with the second hole but cannot move in the horizontal direction DR1. Specifically, the second hole has an annular groove recessed from its hole wall, and the other end of the adjusting screw 11 has a flange protruding outwardly peripherally, which is rotatably embedded in the annular groove of the second hole. Thus, the second hole allows the adjusting screw 11 to rotate but prevents the adjusting screw 11 from moving in the horizontal direction DR1.

[0113] In some embodiments, to facilitate assembly of the adjusting screw 11 and the connecting seat 12, the connecting seat 12 is configured to be formed by two separate sub-parts connected to each other, and the two radially oriented portions of the second hole are respectively defined by these two sub-parts.

[0114] A head support 13 for supporting the subject's head is detachably connected to the upper body 5 of the base 1. A portion of the head support 13 is formed as an arcuate plate 13a that conforms to the contour of the human head (more specifically, the posterior contour of the head). The arcuate plate 13a and the upper body 5 are spaced apart in the vertical direction DR2, and in use, the arcuate plate 13a extends into the examination chamber 18 through the opening 18a.

[0115] Please see also Figures 4 to 7 To provide radio frequency excitation signals to the first coil unit 23 and to acquire magnetic resonance signals from the first coil unit 23, the first coil array 21 further includes eight first radio frequency transceiver circuits 31 respectively connected to the eight first coil units 23, a first radio frequency power divider 25 connected to the radio frequency input terminals (corresponding to the second node n2 described later) of the eight first radio frequency transceiver circuits 31 and capable of providing a first radio frequency signal with a first resonant frequency, and eight first preamplifiers 26 respectively connected to the magnetic resonance signal output terminals (corresponding to the third node n3 described later) of the eight first radio frequency transceiver circuits 31 and capable of amplifying the magnetic resonance signals. Similarly, to provide radio frequency excitation signals to the second coil unit 24 and to acquire magnetic resonance signals from the second coil unit 24, the second coil array 22 further includes eight second radio frequency transceiver circuits 32 respectively connected to the eight second coil units 24, a second radio frequency power divider 27 connected to the radio frequency input terminals of the eight second radio frequency transceiver circuits 32 and capable of providing a second radio frequency signal with a second resonant frequency, and eight second preamplifiers 28 respectively connected to the magnetic resonance signal output terminals of the eight second radio frequency transceiver circuits 32 and capable of amplifying the magnetic resonance signals. For simplicity, Figure 6 Only one of the eight first radio frequency transceiver circuits 31 is shown. Figure 7 Only one of the eight second RF transceiver circuits 32 is shown.

[0116] like Figure 6 As shown, the first radio frequency transceiver circuit 31 includes a first node n1, a second node n2, a third node n3, a radio frequency transmitting branch connected between the second node n2 and the first node n1, and a radio frequency receiving branch connected between the third node n3 and the first node n1. The first node n1 is the radio frequency signal output terminal and the magnetic resonance signal receiving terminal of the first radio frequency transceiver circuit 31, and it is connected to a first coil unit 23 having a first resonant frequency (e.g., 297.2 MHz) via a seventh capacitor C7 and a balun 29. The second node n2 is the radio frequency signal receiving terminal of the first radio frequency transceiver circuit 31, and it is connected to a power output terminal of a first radio frequency power divider 25 via a fifth capacitor C5. The third node n3 is the magnetic resonance signal output terminal of the first radio frequency transceiver circuit 31, and it is connected to the input terminal of a preamplifier via a sixth capacitor C6.

[0117] The first radio frequency power divider 25 has one power input terminal and eight power output terminals. By supplying a radio frequency power signal to its power input terminal, its eight power output terminals can output the same first radio frequency signal with a first resonant frequency. In practice, the aforementioned radio frequency power signal can be provided to the power input terminal of the first radio frequency power divider 25 using the transmitter of the MRI system. When the first coil array 21 is operating in the transmitting state, each power output terminal of the first radio frequency power divider 25 provides a first radio frequency signal with the first resonant frequency to the second node n2 of each first radio frequency transceiver circuit 31, and the first radio frequency signal is then provided to the first coil unit 23 via the radio frequency transmitting branch and the first node n1. The first coil unit 23, resonating at the first resonant frequency, transmits the first radio frequency signal to the examination cavity 18, especially the subject (such as the subject's head) within the examination cavity 18, thereby generating a B1 field at the examination cavity 18.

[0118] The first preamplifier 26 can obtain the first magnetic resonance signal at the first resonant frequency from the first coil unit 23 from the third node n3 of the first RF transceiver circuit 31, and after amplifying the first magnetic resonance signal, supply it to the receiver 300 of the magnetic resonance system 1000. When the first coil array 21 is operating in the receiving state, the first magnetic resonance signal at the first resonant frequency received by the first coil unit 23 is supplied to the third node n3 via the first node n1 and the RF receiving branch, and then provided to the input terminal of the first preamplifier 26 via the third node n3.

[0119] The first node n1 is connected to ground potential GND via the first inductor L1, wherein the self-resonant frequency of the first inductor L1 is the same as the first resonant frequency. Therefore, the first radio frequency signal / first magnetic resonance signal transmitted to the first node n1 does not flow to the ground terminal.

[0120] The radio frequency (RF) transmission branch includes a first diode D1, a bias voltage input node n4, a first capacitor C1, a second capacitor C2, and a third inductor L3. The anode of the first diode D1 is connected to the second node n2, and the cathode is connected to the first node n1. The bias voltage input node n4 is configured to selectively receive a bias voltage supplied by an external circuit (bias voltage generator), and is connected to the anode of the first diode D1 via the second inductor L2 and the second node n2 in sequence. The self-resonant frequency of the second inductor L2 is the same as the first resonant frequency. The first capacitor C1 is connected in parallel with the first diode D1. The second capacitor C2 and the third inductor L3 are connected in series and then in parallel across the first capacitor C1, and therefore also in parallel across the first diode D1. The first diode D1 (with junction capacitance), the first capacitor C1, the second capacitor C2, and the third inductor L3 in the off-state form a resonant blocking circuit at the first resonant frequency.

[0121] With this design, when the bias voltage input node n4 receives a bias voltage higher than the ground potential GND, the first diode D1 is in a conducting state. The first radio frequency signal introduced from the second node n2 can be supplied to the first coil unit 23 through the conducting first diode D1 and the first node n1, enabling the first coil unit 23 to operate in transmit mode. Since the first inductor L1 connected between the first node n1 and the ground potential GND resonates at the first resonant frequency, the first radio frequency signal will not be transmitted to the ground terminal through the first inductor L1, causing power loss, thereby ensuring the transmission efficiency of the first coil array 21. In addition, when the bias voltage input node n4 receives a bias voltage, the second capacitor C2, which has a DC blocking function, can prevent DC current from flowing in the third inductor L3.

[0122] When the first coil unit 23 operates in receiving mode, the bias voltage input node n4 does not receive a bias voltage. Thus, the first diode D1 is in a cutoff state due to the absence of a bias voltage. Since the resonant blocking circuit formed by the cutoff first diode D1, the first capacitor C1, the second capacitor C2, and the third inductor L3 has a resonant frequency of the first resonant frequency, even though the first RF power divider 25 still provides the first RF signal to the second node n2, this first RF signal cannot be transmitted to the first node n1 and the first coil unit 23, thus affecting the reception of the first magnetic resonance signal by the first coil unit 23. More importantly, the first magnetic resonance signal from the first coil unit 23 cannot be transmitted to the second node n2 side through the aforementioned resonant blocking circuit. Therefore, in receiving mode, there is excellent isolation between the receiving and transmitting ends of the first coil unit 23.

[0123] Figure 8 The isolation between the second node n2 and the third node n3, measured when the first coil unit 23 is operating in receiving mode (7.0T ultra-high field), is shown. For comparison, Figure 9 This shows the result after removing the first capacitor C1, the second capacitor C2, and the third inductor L3 from the first RF transceiver circuit 31 (thus connecting with...). Figure 7The structure of the second RF transceiver circuit 32 shown is basically the same. When the first coil unit 23 is working in receive mode (7.0T ultra-high field), the isolation between the second node n2 and the third node n3 is tested. It can be seen that without the first capacitor C1, the second capacitor C2 and the third inductor L3, the isolation between the transmitting end (second node n2) and the receiving end (third node n3) of the first coil unit 23 is -16dB; while after configuring the first capacitor C1, the second capacitor C2 and the third inductor L3, the isolation between the transmitting end (second node n2) and the receiving end (third node n3) of the first coil unit 23 is improved to -32dB. The inventors believe that this phenomenon occurs because, without the first capacitor C1, the second capacitor C2, and the third inductor L3, although the first diode D1 is in a cutoff state because no bias voltage is applied, a portion of the first magnetic resonance signal transmitted to the first node n1 is transmitted to the second node n2 via the first diode D1 due to its junction capacitance. However, with the first capacitor C1, the second capacitor C2, and the third inductor L3 configured, the cutoff state of the first diode D1, the first capacitor C1, the second capacitor C2, and the third inductor L3 constitutes a resonant blocking circuit with a first resonant frequency. Therefore, virtually no magnetic resonance signal can be transmitted to the transmitting end of the coil, and the isolation is significantly improved. Therefore, when designing the first RF transceiver circuit 31, after determining the junction capacitance value of the first diode D1, the first capacitor C1 and the second capacitor C2 with suitable capacitance values, as well as the third inductor L3 with suitable inductance values, can be selected based on calculations and experimental tests to construct a resonant blocking circuit resonating at the first resonant frequency.

[0124] Please continue reading Figure 6 The RF transmission branch also includes a second diode D2, a third capacitor C3, and a fourth inductor L4. The second diode D2 is connected between the second inductor L2 and the second node n2, with its anode facing towards the second inductor L2. The third capacitor C3 is connected between the second inductor L2 and the anode of the first diode D1. The fourth inductor L4 is connected between the second node n2 and the anode of the first diode D1, and its self-resonant frequency is the same as the first resonant frequency.

[0125] The third capacitor C3 and the second diode D2 provide a transmission path for the first radio frequency signal from the second node n2 to the anode of the first diode D1. Furthermore, when the bias voltage is not supplied to the bias voltage input node n4, the second diode D2 reduces both the risk of the first radio frequency signal being transmitted to the first node n1 and the risk of the magnetic resonance signal being transmitted to the second node n2. Specifically, when the bias voltage is supplied to the bias voltage input node n4, compared to the case where the third capacitor C3 is replaced by a wire, the third capacitor C3 can prevent the second diode D2 from being short-circuited and cut off. Obviously, a cut-off second diode D2 cannot provide a transmission path for the first radio frequency signal from the second node n2 to the anode of the first diode D1. In addition, the fourth inductor L4 can provide a transmission path for the bias voltage from the second node n2 to the anode of the first diode D1, and based on the resonance of the fourth inductor L4 at the first resonant frequency, it can disconnect the signal at the first resonant frequency. Compared with the case where the fourth inductor L4 is replaced by a wire, when the bias voltage is not supplied to the bias voltage input node n4, it can reduce the risk of the first radio frequency signal being transmitted to the first node n1 and the risk of the magnetic resonance signal being transmitted to the second node n2.

[0126] The RF receiving branch includes a third diode D3, a fourth capacitor C4, and a fifth inductor L5. The third diode D3 is connected between the first node n1 and the first inductor L1, with its anode facing towards the first node n1. The fourth capacitor C4 is connected between the junction of the third diode D3 and the first inductor L1 (not shown in the attached diagram) and the third node n3. The fifth inductor L5 is connected in parallel with the third diode D3 and the fourth capacitor C4 between the first node n1 and the third node n3. Together with the fourth capacitor C4 and the conducting third diode D3, it forms another resonant blocking circuit with the same resonant frequency as the first resonant frequency. The self-resonant frequency of the fifth inductor L5 is different from the first resonant frequency.

[0127] Because the resonant blocking circuit formed by the fifth inductor L5, the conducting third diode D3, and the fourth capacitor C4 resonates at the first resonant frequency, the signal at the first resonant frequency is blocked. Therefore, in the transmit mode, the first radio frequency signal used to generate the B1 field will not be transmitted to the third node n3, i.e., the receiving end of the coil. Furthermore, because the self-resonant frequency of the fifth inductor L5 is different from the first resonant frequency, in the receive mode (when the third diode D3 is in the off state), the first magnetic resonance signal from the first coil unit 23 can be transmitted to the third node n3 via the fifth inductor L5 and supplied to the first preamplifier 26.

[0128] Additionally, the fifth capacitor C5 is connected between the power output terminal of the first RF power divider 25 and the second node n2, thereby preventing the aforementioned bias voltage from being transmitted to the first RF power divider 25. Furthermore, the sixth capacitor C6 is connected between the input terminal of the first preamplifier 26 and the third node n3, thereby preventing the aforementioned bias voltage from being transmitted to the first preamplifier 26 via the fifth inductor L5.

[0129] The sixth capacitor, C6, is the matching capacitor for the preamplifier and is an adjustable capacitor with an adjustable capacitance value.

[0130] exist Figure 6 In the first node n1, the first node n1 is connected to the first coil unit 23 via the seventh capacitor C7 and the balun 29. The balun 29 is used to suppress the common-mode current on the coaxial shield layer, which can reduce the heat generation and common-mode interference on the coaxial line. The seventh capacitor C7 can prevent the bias voltage from being transmitted to the first coil unit 23.

[0131] Although the resonant blocking circuit consisting of the first diode D1, the first capacitor C1, the second capacitor C2, and the third inductor L3 in the cutoff state provides excellent signal isolation for the first resonant frequency, its construction requires extensive debugging work and is detrimental to reducing hardware costs. The Larmor frequency (second resonant frequency) of the sodium nucleus is significantly lower than that of the hydrogen atom (first resonant frequency). We found that even without omitting the first capacitor C1, the second capacitor C2, and the third inductor L3, at the lower Larmor frequency of the sodium nucleus, the first diode D1 alone is sufficient to achieve adequate isolation between the transmitter and receiver. Therefore, considering the simplicity of debugging and cost-effectiveness, [the circuit is designed to be more efficient]. Figure 6 The first radio frequency transceiver circuit 31 shown refers to the first coil unit 23. Figure 7 The second RF transceiver circuit 32 shown for the second coil unit 24 omits the first capacitor C1, the second capacitor C2, and the third inductor L3, but retains all the remaining electrical components of the first RF transceiver circuit 31. Based on the above description of the first RF transceiver circuit 31, those skilled in the art will understand... Figure 7 The working principle of the second radio frequency transceiver circuit 32 is not described in detail here.

[0132] In the first coil array 21, the eight bias voltage input nodes n4 of the eight RF transceiver circuits can be connected to the same bias voltage generator.

[0133] The number of the first coil unit 23 and the number of the second coil unit 24 are not necessarily eight, and their numbers can be the same or different. However, in order to ensure the quality of magnetic resonance imaging, the number of the first coil unit 23 and the second coil unit 24 should generally not be less than four.

[0134] Please review Figure 4 and Figure 5 The eight first coil units 23 constituting the first coil array 21 are arranged on the outer periphery of the eight second coil units 24 constituting the second coil array 22, and the two are arranged at a certain distance in the radial direction. In this embodiment, the second coil units 24 located on the inner periphery are designed as square coil units, while the first coil units 23 located on the outer periphery are designed as circular coil units.

[0135] Understandably, constructing the second coil unit 24 as a square, compared to the circular first coil unit 23, helps to increase the signal coverage of the second coil array 22, thereby obtaining a wide range of magnetic resonance images of the subject. Although constructing the first coil unit 23 as a square can increase the signal coverage of the first coil array 21, the area of ​​a single square coil unit is larger than that of a single circular coil unit for the same length and width, exhibiting relatively poor transmission efficiency and receiving sensitivity. Moreover, the first coil unit 23 is relatively far from the examination cavity 18 and the subject, and performs magnetic resonance imaging based on hydrogen nuclei with high Larmor frequencies. Therefore, when the first coil unit 23 is constructed as a square, the image quality of hydrogen nuclear magnetic resonance imaging is significantly reduced. Unlike the aforementioned cases, the second coil unit 24 on the inner periphery is constructed in a square shape. Although the transmission efficiency and receiving sensitivity of the second coil unit 24 itself are reduced, it is still possible to obtain high-quality magnetic resonance images that meet the application requirements because the second coil unit 24 is very close to the examination cavity 18 and the object under examination, and the second coil unit 24 is based on sodium nuclei with low Larmor frequency for magnetic resonance imaging.

[0136] Figure 10 This image shows a magnetic resonance imaging (MRI) image of a subject's head obtained using a first coil array 21 based on a Turbo Spin Echo (TSE) sequence and hydrogen nuclear magnetic resonance (NMR), wherein the repetition time is 7000 ms, the echo time is 66 ms, the flip angle is 120°, and the resolution is 1 × 1 × 2 mm. 3 .

[0137] Figure 11The image shows a magnetic resonance imaging (MRI) image of a subject's head obtained using a magnetization-prepared rapid acquisition gradient echo (MPRAGE) sequence based on a first coil array 21 and hydrogen nuclear magnetic resonance (NMR). The repetition time is 2270 ms, the echo time is 1.87 ms, the reversal time is 900 ms, the flip angle is 6°, and the resolution is 1 × 1 × 1 mm. 3 .

[0138] Figure 12 The image shows a magnetic resonance imaging (MRI) image of a subject's head obtained using a first coil array 21 based on a fluid-attenuated inversion recovery (FLAIR) sequence and hydrogen nuclear magnetic resonance (NMR), wherein the repetition time is 9000 ms, the echo time is 76 ms, the inversion time is 2600 ms, the flip angle is 120°, and the resolution is 1×1×2 mm. 3 .

[0139] Figure 13 The image shows magnetic resonance imaging of a subject's head obtained using a second coil array 22 based on a density-adapted 3D radial acquisition (DA-3D-RAD) sequence and sodium nuclear magnetic resonance, with repetition time = 120 ms, echo time = 0.35 ms, flip angle = 90°, 5000 projections, and a resolution of 3×3×3 mm. 3 .

[0140] from Figures 10 to 13 It can be seen that the device 100 can perform 1 mm isotropic hydrogen structure imaging and 3 mm isotropic sodium imaging within a clinically acceptable scan time (20-30 minutes). Furthermore, the hydrogen and sodium images can be well aligned, which facilitates image post-processing.

[0141] As previously described, the base 1 is constructed as a height-adjustable lifting structure. Therefore, when the device 100 is installed on a magnetic resonance examination table of different configurations, the height of the housing 2 can be changed by adjusting the height of the upper body 5 of the base 1, so as to position the examination cavity 18 and the radio frequency coil 3 at the center of the main magnet of the magnetic resonance examination table.

[0142] As previously described, the head support 13 is detachably supported on the base 1. Therefore, the head support 13 can be replaced with a support suitable for supporting other objects being inspected. For example, in... Figure 14In the illustrated embodiment, the head support 13 is detached and replaced with an animal support capable of supporting small animals such as mice or rats, which is detachably supported on the upper body 5 of the base 1. By replacing the head support 13 with an animal support, the device 100 is able to perform magnetic resonance imaging on small animals for scientific research.

[0143] To obtain high-quality magnetic resonance imaging (MRI) images, the small animal being examined can be positioned at the center of the examination cavity 18. However, different animals have different body sizes, and even for the same animal, its position on the support may differ significantly between two MRI examinations. Therefore, this embodiment of the application constructs the animal support as a liftable structure that can be raised and lowered relative to the examination cavity 18, thereby enabling the small animal being examined to be positioned at the center of the examination cavity 18 by adjusting the height of the animal support.

[0144] Specifically, the animal support includes a first part 15, a second part 16, and a locking bolt 17. The first part 15 is detachably connected to the upper body 5 of the base 1 via a screw (not shown) outside the examination cavity 18, and has an upwardly extending insert 15a with a threaded hole extending in the horizontal direction DR1 (not shown). The second part 16 supports the small animal being examined and has a downwardly opening slot 16a that receives the insert 15a in a manner that allows it to move in the vertical direction DR2. The locking bolt 17 engages with the threaded hole of the insert 15a and has a locked state and a released state by rotation. In the released state, the locking bolt 17 allows the second part 16 to move relative to the first part 15 in the vertical direction DR2. In the locked state, the head of the locking bolt 17 presses against the second part 16, thereby fixing the second part 16 and the first part 15 to each other in the vertical direction DR2.

[0145] like Figure 15 As shown in the illustration, this application also proposes a magnetic resonance system 1000, which includes the aforementioned magnetic resonance coil device 100, transmitter 200, and receiver 300. Transmitter 200 is connected to the input terminals of radio frequency power dividers 25 and 27 to generate radio frequency signals supplied to the input terminals of the power dividers. Receiver 300 is connected to the output terminals of preamplifiers 26 and 28 to receive magnetic resonance signals from the tested object from the output terminals of the preamplifiers.

Claims

1. A magnetic resonance coil device, characterized in that, include: The base is designed for detachable attachment to the MRI examination table and is configured as a height-adjustable structure. A housing defining an inspection cavity having an opening facing a horizontal direction, and supported on a base in a manner movable along said horizontal direction, wherein the inspection cavity is used to receive an object to be inspected via said opening; A support base is detachably supported on the base, and a portion of the support base extends into the inspection chamber through the opening; the support base is used to support the object being inspected. A radio frequency coil is installed in the thickness space between the inner and outer surfaces of the housing for transmitting radio frequency signals to the object under test and / or receiving magnetic resonance signals from the object under test. The support base includes: The first part is detachably connected to the base outside the inspection cavity and has an upwardly extending insert with a threaded hole. The second part is for supporting the object under inspection and has a downward-opening slot that receives the insert in a manner that allows it to move in a vertical direction; A locking bolt engages with the threaded hole and has a locked state and a released state by being rotated. In the released state, the second part is allowed to move relative to the first part in the vertical direction. In the locked state, the second part and the first part are fixed to each other in the vertical direction. The base includes: The lower seat is detachably fixed to the magnetic resonance examination table; Lifting mechanism; An upper seat is connected to the upper side of the lower seat via the lifting mechanism, wherein the housing is connected to the upper seat, and the lifting mechanism can be operated to drive the upper seat to rise or fall relative to the lower seat. The lifting mechanism includes: A pair of sliding grooves are formed on the lower body and extend along the horizontal direction, and are spaced apart from each other in a horizontally spaced direction perpendicular to the horizontal direction; A pair of upper sliding grooves are formed on the upper seat and extend along the horizontal direction, and are spaced apart from each other in the spaced direction; A pair of first links are connected to each other in a cross manner at the middle part, in a way that allows them to rotate about the spaced-out direction. The first end of the first link is rotatably connected to the lower seat body, and the second end is slidably and rotatably connected to the first upper slide groove of the pair of upper slide grooves. The first end of the second link is slidably and rotatably connected to the first lower slide groove of the pair of lower slide grooves, and the second end is rotatably connected to the upper seat body. A pair of second links are connected to each other in a cross manner at the middle part, in a way that allows them to rotate about the spaced-out direction. The first end of the first second link is rotatably connected to the lower seat body, and the second end is slidably and rotatably connected to the second upper slide groove of the pair of upper slide grooves. The first end of the second second link is slidably and rotatably connected to the first lower slide groove of the pair of lower slide grooves, and the first end is rotatably connected to the upper seat body. The third link extends along the spacing direction and connects the second end of the first link and the second end of the first link; An adjusting screw extends along the horizontal direction and is screwed into the upper seat. One end is provided with a handwheel, and the other end is rotatably but not movable along the horizontal direction and connected to the third link. The adjusting screw is configured to drive the third link to move along the horizontal direction by manually rotating the handwheel, thereby driving the upper seat to rise and fall relative to the lower seat.

2. The magnetic resonance coil device according to claim 1, characterized in that, By moving the housing relative to the base in the horizontal direction, the object under inspection is completely moved out of the inspection chamber through the opening.

3. The device according to claim 1 or 2, characterized in that, The object being examined is the head of a human body, and the support includes an arc-shaped plate that extends into the examination cavity and is used to support the head.

4. The device according to claim 1, characterized in that, The upper body has two opposite sides with linear guide rails extending along the horizontal direction, and the bottom of the housing has a slider connected to the linear guide rails in a manner that allows it to move along the horizontal direction.

5. The device according to claim 1, characterized in that, The opposite ends of the third link are slidably inserted into the pair of upper slots, and the second ends of the first link and the second ends of the first second link are rotatably connected to the third link.

6. The device according to claim 5, characterized in that, In the horizontal direction, the handwheel is positioned on the side of the inspection chamber opposite to the opening.

7. The device according to claim 5, characterized in that, The other end of the adjusting screw is connected to the third link via a connecting seat, the connecting seat having a first hole through which the third link passes and a second hole for receiving the other end of the adjusting screw, the second end of the adjusting screw being rotatably but not movable in the horizontal direction connected to the second hole.

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