Transmitter coil assembly for neck magnetic resonance imaging

Abstract

This application relates to the field of magnetic resonance imaging (MRI), and more particularly to a transmitting coil assembly for neck MRI. The coil assembly includes: a housing defining a chamber for receiving signals from a subject's neck; a first opening communicating with the chamber; and two notches communicating with the chamber and continuous with the first opening. The first opening is located at the foot-side end of the chamber in the head-to-toe direction of the subject. The two notches are positioned opposite each other in the left-right direction of the subject and are recessed from the edge of the first opening towards the head-to-toe direction, for receiving signals from the subject's left and right shoulders, respectively. A radio frequency transmitting coil, supported by the housing, is used to transmit radio frequency signals to the neck.

Description

Technical Field

[0001] This application relates to the field of nuclear magnetic resonance technology, and more particularly to a transmitter coil assembly for neck magnetic resonance imaging. Background Technology

[0002] The radio frequency transmitting coil assembly mainly consists of a coil and a housing that carries the coil. It is used to transmit radio frequency signals to a target limb part of the subject, such as the neck, to excite the hydrogen nuclei in the neck to generate magnetic resonance signals, and based on this, obtain magnetic resonance images of the neck.

[0003] Traditional transmit coil assemblies for neck MRI typically employ a cylindrical housing design, with nearly flush, flat end faces at both the head and feet. However, the human neck has a relatively small diameter, while the shoulders are much larger. Furthermore, the transmit coil exhibits attenuation at its head-to-feet edges, and cervical spine diagnosis requires visualization of the vertebrae below the shoulders. Therefore, a conventional flush-end design would require the coil assembly's internal chamber to encompass the patient's shoulders, resulting in a significantly larger coil assembly and its internal chamber. Increased internal chamber size leads to a substantial decrease in RF coil efficiency, a marked increase in required transmit power, and a corresponding rise in SAR safety risks. Summary of the Invention

[0004] In view of this, this application provides an optimized transmitter coil assembly for neck magnetic resonance imaging.

[0005] This application discloses a transmitter coil assembly for neck magnetic resonance imaging, comprising:

[0006] The housing defines a cavity for receiving a subject's neck, a first opening communicating with the cavity, and two notches communicating with the cavity and continuous with the first opening. The first opening is located at the foot-side end of the cavity along the head-to-toe direction of the subject. The two notches are arranged opposite to each other in the left-right direction of the subject and are formed by recessing from the edge of the first opening toward the head-to-toe direction, for receiving the subject's left shoulder and right shoulder respectively.

[0007] A radio frequency transmitting coil, supported by the housing, is used to transmit radio frequency signals to the neck.

[0008] In some possible implementations, at least a portion of the radio frequency transmitting coil extends at a first portion of the housing, the first portion being the portion of the housing that overlaps with the notch in the circumferential direction surrounding the neck.

[0009] In some possible implementations, the first portion includes a front portion and a rear portion disposed opposite to each other in the anteroposterior direction of the subject and separated by the two notches, a portion of the radio frequency transmitting coil extending in the front portion and another portion of the radio frequency transmitting coil extending in the rear portion.

[0010] In some possible implementations, the radio frequency coil is a birdcage coil, which includes:

[0011] A first end ring and a second end ring are arranged spaced apart in the head-to-feet direction and surround the cavity respectively, wherein the first end ring extends along the edge shape of the first opening and the edge shape of the notch;

[0012] Multiple legs are connected to the first end ring and the second end ring, respectively.

[0013] In some possible implementations, the plurality of legs include a longer leg connected to a first extension of the first end ring and a shorter leg connected to a second extension of the first end ring, wherein the first extension is an extension of the first end ring corresponding to the edge of the first opening, and the second extension is an extension of the first end ring corresponding to the edge of the notch.

[0014] Each of the legs includes a capacitor connected in series with the leg, and the capacitance of the capacitor in the longer leg is less than the capacitance of the capacitor in the shorter leg.

[0015] In some possible implementations, the chamber is also used to receive the subject's head and has a nasal receiving space corresponding to the nose of the head, the nasal receiving space protruding toward the outer periphery of the chamber;

[0016] The first leg of the longer leg extends across the nasal receiving space and has a protruding extension at the nasal receiving space that protrudes toward the outer periphery of the cavity relative to the other portions of the first leg.

[0017] The capacitance of the capacitor in the first leg is configured such that the reactance of the first leg is the same as the reactance of each of the other legs.

[0018] In some possible implementations, the radio frequency transmitting coil includes multiple coil units.

[0019] In some possible implementations, including:

[0020] A base for supporting the subject's neck, the housing being connected to the base in a manner that allows it to move along the head-to-toe direction;

[0021] The component is configured to receive the subject's neck via the first opening and the two notches respectively by moving the housing from the subject's head side to the foot side.

[0022] In some possible implementations, including:

[0023] A guide rail, extending in the head-to-feet direction, slidably connects the housing to the base;

[0024] The base supports the neck by supporting the subject's head and back shoulders.

[0025] In some possible implementations, the housing further defines a second opening in communication with the chamber and opposite to the first opening in the head-to-toe direction, the second opening being configured to allow at least a portion of the subject's head to extend out.

[0026] The transmit coil assembly for neck magnetic resonance imaging provided in the embodiments of this application helps to avoid the large size of the internal chamber and radio frequency coil, thereby providing higher transmit efficiency and lower SAR security risks. Attached Figure Description

[0027] 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.

[0028] Figure 1 This is a schematic diagram of the transmitting coil assembly provided in the embodiment of this application in the preparation state during use.

[0029] Figure 2 This is a schematic diagram of the transmitting coil assembly provided in the embodiments of this application in its usage state.

[0030] Figure 3 Is Figure 1 A schematic diagram of the transmitting coil assembly in the specified state.

[0031] Figure 4 Is Figure 2 A schematic diagram of the transmitting coil assembly in the specified state.

[0032] Figure 5 yes Figure 3 A partial diagram showing the casing when it is opened.

[0033] Figure 6 yes Figure 5 Side view.

[0034] Figure 7 yes Figure 5 The front view.

[0035] Explanation of reference numerals in the attached figures:

[0036] DR1 - Head-to-toe direction, DR2 - Circumferential direction;

[0037] 100 - Transmitting coil assembly, PP - Subject;

[0038] 1-Shell, 1a-First part, 1a1-Front part, 1a2-Lower part;

[0039] 2-Cavity, 2a-Foot side end, 2b-Head side end, 2c-Nose receiving space;

[0040] 3-RF transmitting coil;

[0041] 4-First end ring, 4a-First extension segment, 4b-Second extension segment;

[0042] 5-Second end ring;

[0043] 6 - outrigger, 6A - longer outrigger, 6B - shorter outrigger;

[0044] 7-First opening;

[0045] 8-Second opening;

[0046] 9-Gap;

[0047] 10-Base;

[0048] 11-Guide rail. Detailed Implementation

[0049] 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.

[0050] 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.

[0051] Figures 1 to 7 A transmitting coil assembly 100 (hereinafter, sometimes simply referred to as assembly 100) according to an embodiment of this application is shown, which is suitable for magnetic resonance imaging of the neck of a subject PP, and mainly includes a housing 1 and a radio frequency transmitting coil 3 supported by the housing 1.

[0052] The shell 1 is mostly made of plastic, which defines the chamber 2, the first opening 7, the second opening 8 and two notches 9.

[0053] Chamber 2 is roughly cylindrical in shape and is used to receive the neck of the subject's PP. Furthermore, chamber 2 can also receive the head and chest of the subject's PP (e.g., in the head-to-toe direction DR1, receiving the lower half of the head and the upper half of the chest) in order to better accommodate the entire neck of the subject's PP, although this is not necessary.

[0054] Both the first opening 7 and the second opening 8 communicate with the chamber 2 and are opposite each other in the head-to-toe direction DR1 of the subject's PP. More specifically, the first opening 7 is located at the foot-side end 2a of the chamber 2 in the head-to-toe direction DR1 of the subject's PP, and correspondingly, the second opening 8 is located at the head-side end 2b of the chamber 2 in the head-to-toe direction DR1 of the subject's PP. The first opening 7 is sized to allow the head of the subject's PP to extend into it, thereby allowing the neck of the subject's PP to enter the chamber 2 through the first opening 7. The second opening 8 may be sized to allow at least a portion (e.g., the top of the head) of the subject's PP to protrude, so that the chamber 2 can accommodate different subjects' PPs in the head-to-toe direction DR1. In other embodiments, the head-side end 2b of the chamber 2 is closed, i.e., it does not have a second opening 8.

[0055] Each of the two notches 9 communicates with and is continuous with the chamber 2 and the first opening 7. The two notches 9 are positioned opposite each other in the left-right direction of the subject's PP and are formed by recesses from the edges (left and right edges) of the first opening 7 toward the head-to-toe direction DR1. With this design, during use, the two notches 9 can be used to receive the left and right shoulders of the subject's PP respectively, thus allowing as much of the subject's neck as possible to be accommodated within the chamber 2 without having to design a relatively large circumferential DR2 size of the chamber 2, thereby improving the accuracy of magnetic resonance imaging.

[0056] The radio frequency transmitting coil 3 is installed in the interlayer space inside the wall of the housing 1 and is supported and positioned by the housing 1. It is used to transmit radio frequency signals to the neck to excite the hydrogen nuclei in the neck of the subject PP to generate magnetic resonance signals.

[0057] Furthermore, at least a portion of the radio frequency transmitting coil 3 extends at a first portion 1a of the housing 1, which is the portion of the housing 1 that overlaps with the notch 9 on the circumferential DR2 surrounding the neck. Therefore, the radio frequency transmitting coil 3 covers the neck of the subject PP at least at the first portion 1a of the housing 1 and transmits radio frequency signals to it efficiently.

[0058] More specifically, the first part 1a includes a front part 1a1 and a rear part disposed opposite to each other in the front-back direction of the subject PP and separated by two notches 9, and both the front part 1a1 and the rear part are provided with radio frequency coils, that is, a part of the radio frequency transmitting coil 3 extends in the front part 1a1 and another part of the radio frequency transmitting coil 3 extends in the rear part.

[0059] like Figure 5 and Figure 6 As shown, the radio frequency transmitting coil 3 is a birdcage coil, comprising a first end ring 4 and a second end ring 5 spaced apart in the head-to-toe direction DR1, and a plurality of legs 6 connecting the first end ring 4 and the second end ring 5 respectively. The first end ring 4 and the second end ring 5 respectively surround the chamber 2, wherein the second end ring 5 is a relatively standard circular ring, while the first end ring 4 extends into an irregular ring shape following the edge shape of the first opening 7 and the edge shape of the notch 9. Therefore, the two ring segments of the first end ring 4 in the front-to-back direction of the subject PP (i.e., the first extension segment 4a mentioned later) extend at the front portion 1a1 and the rear portion respectively. In addition, each leg 6 includes a capacitor (not shown) connected in series with the leg 6.

[0060] Because the first end ring 4 is constructed in the aforementioned irregular ring shape, the legs 6 of the birdcage coil have different lengths. Specifically, the multiple legs 6 include a longer leg 6A connected to a first extension 4a of the first end ring 4 and a shorter leg 6B connected to a second extension 4b of the first end ring 4. The first extension 4a is the extension of the first end ring 4 corresponding to the edge of the first opening 7, and the second extension 4b is the extension of the first end ring 4 corresponding to the edge of the notch 9. Furthermore, the capacitance of the capacitor in the longer leg 6A is less than the capacitance of the capacitor in the shorter leg 6B, so that the reactance of the longer leg 6A is the same as that of the shorter leg 6B, thereby improving the uniformity of the radio frequency signal emitted by the radio frequency transmitting coil 3.

[0061] As mentioned above, in this embodiment, chamber 2 is also used to receive the head of the subject PP. More specifically, chamber 2 has a nasal receiving space 2c corresponding to the nose of the subject PP. The nasal receiving space 2c protrudes towards the outer periphery of chamber 2 to provide separate accommodating space for the nose of the head when chamber 2 receives the head of the subject PP, so that it is not necessary to increase the overall circumferential DR2 dimension of chamber 2 at the nose position.

[0062] Furthermore, in some embodiments, one of the longer legs 6A (referred to as the first leg 6 for ease of description) extends across the aforementioned nasal receiving space 2c and has a protruding extension at the nasal receiving space 2c that protrudes towards the outer periphery of the cavity 2 relative to the other portions of the first leg 6. Since the other legs 6 do not have such a protruding extension, this causes a variation in the reactance value of the legs 6. To address this, the capacitance value of the capacitor of the first leg 6 can be configured such that the reactance value of the first leg 6 is the same as the reactance value of each of the other legs 6.

[0063] In other embodiments, the radio frequency transmitting coil 3 is an array coil consisting of a plurality of coil units, and at least one coil unit extends at the upper portion of the first part 1a of the housing 1, and at least another coil unit extends at the lower portion 1a2 of the first part 1a of the housing 1.

[0064] In other words, in order to accommodate the protruding shape of the nasal cavity, the shape of the first leg 6 is different from that of each of the other legs 6. If the first leg 6 is not further modified, the signal uniformity of the birdcage coil will deteriorate due to the change in the shape of the first leg 6. The third capacitor connected in series with the first leg 6 makes the reactance value of the first leg 6 the same as that of each of the other legs 6, thus ensuring the signal uniformity of the birdcage coil.

[0065] The component 100 also includes a base 10 and a guide rail 11. The base 10 is formed in a generally horizontally extending plate shape, supporting the neck of the patient (PP) by supporting the head and back of the shoulders, wherein the patient (PP) is in a supine position for MRI examination. The guide rail 11 extends in the head-to-toe direction DR1 and slidably connects the housing 1 to the upper side of the base 10. In use, by moving the housing 1 from the head side of the patient (PP) toward the foot side, the chamber 2 receives the neck of the patient (PP) through the first opening 7, and the two notches 9 receive the left and right shoulders of the patient (PP) respectively. Based on this design, the position of the housing 1 and the chamber 2 relative to the patient (PP) in the head-to-toe direction DR1 can be adjusted to obtain the desired MRI image.

[0066] In other embodiments, the base 10 may be designed as a reclining bed configuration, thereby supporting the entire body of the subject PP in a supine position.

Claims

1. A transmit coil assembly for magnetic resonance imaging of the neck, characterized by include: The housing defines a cavity for receiving a subject's neck, a first opening communicating with the cavity, and two notches communicating with the cavity and continuous with the first opening. The first opening is located at the foot-side end of the cavity along the head-to-toe direction of the subject. The two notches are arranged opposite to each other in the left-right direction of the subject and are formed by recessing from the edge of the first opening toward the head-to-toe direction, for receiving the subject's left shoulder and right shoulder respectively. A radio frequency transmitting coil, supported by the housing, is used to transmit radio frequency signals to the neck.

2. The assembly of claim 1, wherein, At least a portion of the radio frequency transmitting coil extends at a first portion of the housing, the first portion being the portion of the housing that overlaps with the notch in the circumferential direction surrounding the neck.

3. The assembly of claim 2, wherein, The first part includes a front portion and a rear portion disposed opposite to each other in the front-rear direction of the subject and separated by the two notches, a portion of the radio frequency transmitting coil extending in the front portion and another portion of the radio frequency transmitting coil extending in the rear portion.

4. The component according to claim 1, 2, or 3, characterized in that, The radio frequency coil is a birdcage coil, which includes: A first end ring and a second end ring are arranged spaced apart in the head-to-feet direction and surround the cavity respectively, wherein the first end ring extends along the edge shape of the first opening and the edge shape of the notch; Multiple legs are connected to the first end ring and the second end ring, respectively.

5. The component according to claim 4, characterized in that, The plurality of legs include a longer leg connected to a first extension of the first end ring and a shorter leg connected to a second extension of the first end ring, wherein the first extension is an extension of the first end ring corresponding to the edge of the first opening, and the second extension is an extension of the first end ring corresponding to the edge of the notch. Each of the legs includes a capacitor connected in series with the leg, and the capacitance of the capacitor in the longer leg is less than the capacitance of the capacitor in the shorter leg.

6. The assembly of claim 5, wherein, The chamber is also used to receive the head of the subject and has a nasal receiving space corresponding to the nose of the head, the nasal receiving space protruding toward the outer periphery of the chamber; The first leg of the longer leg extends across the nasal receiving space and has a protruding extension at the nasal receiving space that protrudes toward the outer periphery of the cavity relative to the other portions of the first leg. The capacitance of the capacitor of the first leg is configured such that the reactance of the first leg is the same as the reactance of each of the other legs.

7. The component according to claim 1, characterized in that, The radio frequency transmitting coil includes multiple coil units.

8. The component according to claim 1, characterized in that, include: A base for supporting the subject's neck, the housing being connected to the base in a manner that allows it to move along the head-to-toe direction; The component is configured to receive the subject's neck via the first opening and to receive the subject's left and right shoulders via the two notches by moving the housing from the subject's head side to the foot side.

9. The component according to claim 8, characterized in that, include: A guide rail, extending in the head-to-feet direction, slidably connects the housing to the base; The base supports the neck by supporting the subject's head and back shoulders.

10. The component according to claim 8, characterized in that, The housing also defines a second opening in communication with the chamber and opposite to the first opening in the head-to-toe direction, the second opening being configured to allow at least a portion of the subject's head to extend out.

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