Overmolded resonator for RF coil

Abstract

A method for manufacturing an over-molded resonator for a radio frequency receive coil assembly (180) of a magnetic resonance imaging system (100), the method comprising providing a pair of wires (250), where each wire (250) of the pair of wires (250) has a set desired length. The method also includes holding the pair of wires (250) in a fixed spatial arrangement relative to each other. The method further includes overmolding a dielectric material (256) over the pair of wires (250) to form an overmolded wire assembly (248). The method even further includes coupling the pair of wires (250) to an electronic unit (185).

Description

Background Technology

[0001] The subject matter disclosed herein relates to medical imaging, and more specifically to overmolded resonators for radio frequency (RF) receiving coils in magnetic resonance imaging (MRI) systems.

[0002] Non-invasive imaging techniques allow for the acquisition of images of a patient's or subject's internal structures or features without the need for invasive procedures. Specifically, such non-invasive imaging techniques rely on various physical principles (such as differential transmission of X-rays through a target volume, sound wave reflection within the volume, paramagnetism of different tissues and materials within the volume, and the disintegration of the target radionuclide within the body) to acquire data and construct images or otherwise represent the observed internal features of a patient or subject.

[0003] During MRI, when material such as human tissue is subjected to a uniform magnetic field (polarization field B0), the individual magnetic moments of the spins within the tissue attempt to align with that polarization field, but precess around it in a random order at their characteristic Larmor frequencies. If the material or tissue is subjected to a magnetic field (excitation field B1) located in the xy-plane and close to the Larmor frequency, the net alignment torque, or "longitudinal magnetization," M... z It can be rotated or "tilted" into the xy plane to produce a net transverse magnetic moment M. t After the excitation signal B1 is terminated, a signal is emitted by the excited spin, and this signal can be received and processed to form an image.

[0004] When these signals are used to generate images, the magnetic field gradient (G) is employed. x G y and G z Typically, the area to be imaged is scanned in a series of measurement cycles, during which these gradient fields vary depending on the specific localization method used. The resulting set of received nuclear magnetic resonance (NMR) signals is digitized and processed to reconstruct the image using one of many well-known reconstruction techniques.

[0005] This MRI system utilizes an RF coil receiver coil. The RF receiver coil includes resonators that need to be manufactured according to specific standards. The manufacture of these resonators presents challenges. Summary of the Invention

[0006] The following provides an overview of some embodiments disclosed herein. It should be understood that these aspects are provided merely to give the reader a brief overview of these particular embodiments, and are not intended to limit the scope of this disclosure. In fact, this disclosure may cover aspects that may not be shown below.

[0007] In one embodiment, a method is provided for manufacturing an overmolded resonator for a radio frequency receiving coil assembly for a magnetic resonance imaging system. The method includes providing a pair of wires, each of the wires having a predetermined desired length. The method further includes holding the pair of wires in a spatial arrangement fixed relative to each other. The method further includes overmolding a dielectric material over the pair of wires to form an overmolded wire assembly. The method even further includes coupling the pair of wires to an electronic unit.

[0008] In another embodiment, a method is provided for manufacturing an overmolded resonator for a radio frequency receiving coil assembly for a magnetic resonance imaging system. The method includes placing each of a pair of wires into a corresponding reservoir of a forming device, wherein each of the pair of wires has a predetermined desired length, and the forming device holds the pair of wires in a parallel arrangement spaced a fixed distance from each other. The method further includes overmolding a dielectric material over the pair of wires and the forming device to form an overmolded wire assembly. The method further includes coupling the pair of wires to an electronic unit.

[0009] In a further embodiment, a radio frequency (RF) receiving coil assembly for a magnetic resonance imaging system is provided. The RF receiving coil assembly includes an RF coil. The RF coil includes a plurality of loops. Each loop includes an overmolded wire assembly having a plurality of overmolded resonators. Each overmolded wire assembly includes a pair of wires, each wire disposed in a corresponding reservoir of a forming device, each wire in the pair having a predetermined desired length, the forming device holding the pair of wires in a parallel arrangement spaced a fixed distance from each other, and overmolding a dielectric material over the pair of wires and the forming device. Attached Figure Description

[0010] These and other features, aspects, and advantages of the invention will be better understood when the following detailed description is read with reference to the accompanying drawings, in which similar symbols denote similar parts throughout the drawings, wherein:

[0011] Figure 1 An embodiment of a magnetic resonance imaging (MRI) system suitable for use with the disclosed techniques is illustrated;

[0012] Figure 2 This is a schematic diagram of an RF coil array and its topology according to various aspects of this disclosure;

[0013] Figure 3 It is a cross-section of the RF coil according to various aspects of this disclosure;

[0014] Figure 4This is a schematic diagram of another topology of RF coils within an RF coil array (e.g., a bundle of RF coil arrays) according to various aspects of this disclosure;

[0015] Figure 5 This is a flowchart of a method for manufacturing an overmolded resonator for a radio frequency receiving coil assembly for a magnetic resonance imaging system, according to various aspects of this disclosure.

[0016] Figure 6 This is a flowchart of a method for manufacturing an overmolded resonator for a radio frequency receiving coil assembly for a magnetic resonance imaging system, according to various aspects of this disclosure (e.g., using a forming device).

[0017] Figure 7 This is a flowchart of a method for manufacturing an RF receiver coil assembly having an overmolded resonator according to various aspects of this disclosure;

[0018] Figure 8 This is a schematic diagram of a wire assembly with a sheathing formed according to various aspects of this disclosure;

[0019] Figure 9 This is a schematic diagram of an overmolded wire assembly according to various aspects of this disclosure (e.g., having overmolded additional features);

[0020] Figure 10 This is a schematic diagram of an overmolded wire assembly according to various aspects of this disclosure (e.g., having overmolded additional features and twisted portions);

[0021] Figure 11 This is a schematic diagram of an overmolded wire assembly according to various aspects of this disclosure (e.g., having overmolded additional features, notches, and twists).

[0022] Figure 12 This is a schematic diagram of the coupling between the end of the overmolded wire assembly and the electronic unit according to various aspects of this disclosure;

[0023] Figure 13 This is a schematic diagram of the longitudinal end of the forming device according to various aspects of this disclosure;

[0024] Figure 14 This is a schematic diagram of the longitudinal ends of a shaper that holds a pair of wires according to various aspects of this disclosure;

[0025] Figure 15 This is a schematic diagram of the longitudinal end of a wire assembly that is overmolded according to various aspects of this disclosure;

[0026] Figure 16 This is a perspective view of a wire assembly with an overlay formed according to various aspects of this disclosure;

[0027] Figure 17 This is a schematic diagram of the longitudinal end of a wire assembly with a first fixed distance between the wires, according to various aspects of this disclosure;

[0028] Figure 18 This is a schematic diagram of the longitudinal end of a wire assembly with a second fixed distance between the wires, according to various aspects of this disclosure;

[0029] Figure 19 This is a perspective view of a forming apparatus according to various aspects of this disclosure; and

[0030] Figure 20 Based on the various aspects of this disclosure Figure 19 A schematic diagram of the longitudinal end of the overmolded wire assembly in the forming device. Detailed Implementation

[0031] One or more specific implementations will be described below. To provide a concise description of these implementations, not all features of an actual implementation will be described in this specification. It should be understood that in the development of any such actual implementation, as in any engineering or design project, many implementation-specific decisions must be made to achieve the developer's specific objectives, such as complying with system-related and business-related constraints that may differ from implementation to implementation. Furthermore, it should be understood that such development efforts may be complex and time-consuming, but remain routine tasks of design, fabrication, and manufacturing for those skilled in the art who benefit from this disclosure.

[0032] When describing elements of various embodiments of the subject matter of this invention, the articles “a,” “an,” “the,” and “described” are intended to indicate the presence of one or more elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that additional elements may be present in addition to the listed elements. Furthermore, any numerical examples in the following discussion are intended to be non-limiting, and therefore the additional values, ranges, and percentages are within the scope of the disclosed embodiments.

[0033] While the various aspects discussed below are presented in the context of medical imaging, it should be understood that the disclosed techniques are not limited to this medical context. In fact, the examples and explanations provided in this medical context are merely for illustrative purposes by providing real-world examples of implementation and application. However, the disclosed techniques can also be used in other contexts, such as image reconstruction for non-destructive inspection of manufactured parts or goods (i.e., quality control or quality inspection applications) and / or non-invasive inspection of packages, boxes, suitcases, etc. (i.e., security or screening applications). Generally speaking, the disclosed techniques can be used in any imaging or screening context or in image processing or photography field, where a set or class of acquired data undergoes a reconstruction process to generate an image or volume.

[0034] Manufacturing resonators for RF coils (e.g., within a loop or channel) is a difficult process. The disclosed embodiments provide techniques for manufacturing overmolded resonators for RF coils. In one embodiment, a method for manufacturing an overmolded resonator for an RF receiver coil assembly for a magnetic resonance imaging system includes providing a pair of wires, each of which has a predetermined desired length. The method further includes holding the pair of wires in a spatial arrangement fixed relative to each other. The method further includes overmolding a dielectric material (e.g., an insulator) over the pair of wires to form an overmolded wire assembly. The method even further includes coupling the pair of wires to an electronic unit.

[0035] In some embodiments, the method further includes placing each of the pair of wires into a corresponding reservoir of a forming device, wherein the forming device holds the pair of wires in a parallel arrangement spaced a fixed distance from each other. In some embodiments, the method further includes overmolding a dielectric material over the pair of wires and the forming device. In some embodiments, the forming device is made of a chemically inert and flexible material. In some embodiments, the method further includes twisting the forming device holding the pair of wires before overmolding with the dielectric material. In some embodiments, a corresponding outer edge of each reservoir of the forming device includes a feature for clamping a corresponding wire of the pair of wires. In some embodiments, the overmolded resonator has distributed capacitance. In some embodiments, the method further includes cutting at least one wire of the pair of wires while holding it before overmolding with the dielectric material. In some embodiments, overmolding includes overmolding additional features onto an overmolded member disposed above the pair of wires. In some embodiments, the additional feature includes a corresponding strain relief member located at a corresponding end of the overmolded conductor assembly, wherein the corresponding strain relief member is configured to snap into the power supply board (e.g., printed circuit board) of the electronic unit.

[0036] In one embodiment, a method for manufacturing an overmolded resonator for a radio frequency receiving coil assembly for a magnetic resonance imaging system includes placing each of a pair of wires into a corresponding reservoir of a forming device, wherein each of the pair of wires has a predetermined desired length, and the forming device holds the pair of wires in a parallel arrangement spaced a fixed distance from each other. The method further includes overmolding a dielectric material (e.g., an insulator) over the pair of wires and the forming device to form an overmolded wire assembly. The method further includes coupling the pair of wires to an electronic unit.

[0037] In some embodiments, the forming device is made of a chemically inert and flexible material. In some embodiments, the method further includes twisting the forming device holding the pair of wires before overmolding with a dielectric material. In some embodiments, the respective outer edge of each reservoir of the forming device includes a feature for clamping a respective wire of the pair of wires. In some embodiments, the overmolded resonator has distributed capacitance. In some embodiments, the method further includes cutting at least one wire of the pair of wires while it is held by the forming device before overmolding with a dielectric material. In some embodiments, overmolding includes overmolding additional features onto an overmolded member disposed above the pair of wires. In some embodiments, the additional features include a respective strain relief member located at a respective end of the overmolded wire assembly, wherein the respective strain relief member is configured to snap into a feed plate of an electronics unit.

[0038] In one embodiment, a radio frequency (RF) receiver coil assembly for a magnetic resonance imaging system is provided. The RF receiver coil assembly includes an RF coil. The RF coil includes a plurality of loops. Each loop includes an overmolded conductor assembly having a plurality of overmolded resonators. Each overmolded conductor assembly includes a pair of conductors, each conductor disposed in a respective reservoir of a forming device, each conductor in the pair having a predetermined desired length, the forming device holding the pair of conductors in a parallel arrangement spaced a fixed distance from each other, and overmolding a dielectric material over the pair of conductors and the forming device. In some embodiments, each overmolded conductor assembly includes a corresponding strain relief member overmolded at a corresponding end of the overmolded conductor assembly, wherein the corresponding strain relief member is configured to snap into a feed plate of an electronics unit.

[0039] The disclosed embodiments enable the creation of assemblies (e.g., overmolded wire assemblies) with dielectric material overmolded parts to desired lengths and features. The disclosed embodiments provide a more static method or process for more precisely positioning wires (i.e., controlling wire spacing) within the dielectric material. The disclosed embodiments enable the overmolding of advanced features (e.g., strain relief elements), providing a robust and simple interface connection to the feedboard of the electronic unit. The disclosed embodiments enable the inclusion of slow, linear torsion (e.g., approximately 90 or 180 degrees per 5 centimeters) in the assembly for better bending along both axes. The disclosed embodiments provide a more reliable method for manufacturing resonators (and rings) for RF coils.

[0040] Considering the above, Figure 1 The magnetic resonance imaging (MRI) system 100 is schematically illustrated as including a scanner 102, a scanner control circuitry system 104, and a system control circuitry system 106. According to the embodiments described herein, the magnetic resonance imaging system 100 is generally configured to perform MR imaging.

[0041] System 100 also includes: a remote access and storage system or device, such as a Picture Archiving and Communication System (PACS) 108; or other devices, such as remote radiology equipment, enabling on-site or remote access to data acquired by system 100. In this way, MR data can be acquired and then processed and evaluated on-site or remotely. While the magnetic resonance imaging system 100 may include any suitable scanner or detector, in the illustrated embodiment, system 100 includes a whole-body scanner 102 with a housing 120 through which an aperture 122 is formed. A diagnostic table 124 can be moved into the aperture 122 to allow a patient 126 to be positioned therein for imaging of selected anatomical structures within the patient's body.

[0042] Scanner 102 includes a series of associated coils for generating a controlled magnetic field used to excite gyromagnetic material within the anatomical structures of the subject being imaged. Specifically, a primary magnetic coil 128 is provided to generate a primary magnetic field B0 generally aligned with an aperture 122. A series of gradient coils 130, 132, and 134 allow the generation of a controlled gradient magnetic field during the examination sequence for positional encoding of certain gyromagnetic nuclei within the patient 126. A radio frequency (RF) coil 136 (e.g., an RF transmission coil) is configured to generate RF pulses for exciting certain gyromagnetic nuclei within the patient. In addition to the coils that may be located locally on scanner 102, system 100 also includes a set of receiving coils or RF receiving coils 138 (e.g., an array of coils) configured to be placed proximal to (e.g., against) the patient 126. As an example, receiving coils 138 may include a main coil, such as a cervical / thoracic / lumbar (CTL) coil, a head coil, a single-sided spinal coil, etc. Generally, the receiving coil 138 is placed near or above the patient 126 in order to receive weak radio frequency signals generated by certain magnetic nuclei in the patient's body when the patient 126 returns to its relaxed state (weak in relation to the transmission pulses generated by the scanner coil).

[0043] The various coils of system 100 are controlled by an external circuit system to generate desired fields and pulses and to read out emissions from the gyromagnetic material in a controlled manner. In an illustrated embodiment, a main power supply 140 powers the primary field coil 128 to generate the main magnetic field B0. Power inputs (e.g., power from a utility or grid), a power distribution unit (PDU), a power supply (PS), and drive circuitry 150 may together provide power to cause the gradient field coils 130, 132, and 134 to generate pulses. Drive circuitry 150 may include an amplification and control circuit system for supplying current to the coils according to a sequence of digitized pulses output by scanner control circuitry 104.

[0044] Another control circuit 152 is provided for regulating the operation of the radio frequency coil 136. Circuit 152 includes a switching device for alternating between an active operating mode and a passive operating mode, wherein the radio frequency coil 136 transmits a signal and does not transmit a signal, respectively. Circuit 152 also includes an amplification circuit system configured to generate radio frequency pulses. Similarly, a receiving coil 138 is connected to a switch 154 capable of switching the receiving coil 138 between a receiving mode and a non-receiving mode. Thus, in receiving mode, the receiving coils 138 resonate with the radio frequency signal generated by the release of the vortex nucleus within the patient 126, and in non-receiving mode, they do not resonate with the radio frequency energy from the transmitting coil (i.e., coil 136) to prevent undesirable operation. Additionally, the receiving circuit 156 is configured to receive data detected by the receiving coil 138 and may include one or more multiplexing and / or amplification circuits.

[0045] It should be noted that although the scanner 102 and the control / amplifier circuit system described above are illustrated as being coupled by a single wire, in practice, many such wires may exist. For example, separate wires may be used for control, data communication, power transmission, etc. Furthermore, appropriate hardware may be provided along each type of wire for proper processing of data and current / voltage. In practice, various filters, digitizers, and processors may be provided between the scanner and either or both of the scanner control circuit system 104 and system control circuit system 106.

[0046] As illustrated, the scanner control circuitry 104 includes an interface circuit 158 ​​that outputs signals for driving the gradient field coil and the radio frequency coil, and for receiving data representing magnetic resonance signals generated in the examination sequence. The interface circuit 158 ​​is coupled to a control and analysis circuitry 160. Based on a defined scheme selected via system control circuitry 106, the control and analysis circuitry 160 executes commands for driving circuitry 150 and circuitry 152.

[0047] The control and analysis circuit 160 is also used to receive magnetic resonance signals and perform subsequent processing before sending the data to the system control circuit 106. The scanner control circuit 104 also includes one or more memory circuits 162 that store configuration parameters, pulse sequence descriptions, inspection results, etc. during operation.

[0048] Interface circuitry 164 is coupled to control and analysis circuitry 160 for exchanging data between scanner control circuitry system 104 and system control circuitry system 106. In some embodiments, control and analysis circuitry 160, while exemplified as a single unit, may include one or more hardware devices. System control circuitry 106 includes interface circuitry 166 that receives data from scanner control circuitry system 104 and transmits data and commands back to scanner control circuitry system 104. Control and analysis circuitry 168 may include a CPU in a general-purpose or special-purpose computer or workstation. Control and analysis circuitry 168 is coupled to memory circuitry 170 to store programming code for operating the magnetic resonance imaging system 100, and to store processed image data for subsequent reconstruction, display, and transmission. The programming code may execute one or more algorithms configured to perform reconstruction of the acquired data when executed by a processor.

[0049] Additional interface circuitry 172 may be provided for exchanging image data, configuration parameters, etc., with external system components, such as remote access and storage device 108. Finally, system control and analysis circuitry 168 may be communicatively coupled to various peripheral devices to facilitate the operator interface and the generation of hard copies of reconstructed images. In the illustrated embodiment, these peripheral devices include a printer 174, a monitor 176, and a user interface 178, which includes devices such as a keyboard, mouse, and touchscreen (e.g., integrated with monitor 176).

[0050] Figure 2 This is a schematic diagram of an RF coil assembly 180 (e.g., an RF receiver coil assembly) having coil elements (overmolded resonators or rings). The RF coil assembly 180 can be used in magnetic resonance imaging systems (e.g., Figure 1In a magnetic resonance imaging (MRI) system 100, an RF coil assembly 180 includes an RF coil 184 having multiple coil elements 186 (e.g., loops, channels, or overmolded resonators). Each element 186 is coupled to an electronics unit 185, which is coupled to a coil interface cable 187. The coil interface cable 187 for each coil element 186 is coupled to an electrical connector interface or interface circuitry system 188 (e.g., a balun, such as an integrated balun cable harness, which can act as an RF notch filter). The electrical connector interface 188 (via cable 190) is coupled to a P-connector 192 (e.g., a port connector) that enables the RF coil assembly 180 to be coupled (e.g., via a wired connection) to an interface of the MRI system that couples the imaging components to processing components. In some embodiments, the RF coil assembly 180 may be without a wired connection and may be configured to be used wirelessly with the MRI system during an MRI scan (e.g., for coupling the imaging components to wireless components).

[0051] Each element (or ring) 186 may consist of an overmolded resonator coil element coupled to a printed circuit board module (e.g., electronic unit 185). Each element 186 (and associated resonator coil element) includes a distributed capacitance configuration. The resonator with distributed capacitance enables asymmetric drive of the transmission line structure. Each electronic unit 185 may include various components (e.g., decoupling circuitry, impedance inverter circuitry, and preamplifier). The RF coil 184 may utilize AIR from General Electric Healthcare. TM The design utilizes coil technology. This allows the RF coil 184 to be lightweight and flexible. In some embodiments, each element 186 is stretchable (e.g., due to the use of a zigzag or zigzag structure). Furthermore, the coil elements 186 of the RF coil 184 are transparent, thus contributing to the signal-to-noise ratio.

[0052] A radio frequency (RF) coil 184 is disposed within a flexible housing 194 (e.g., a blanket). As depicted, the flexible housing 194 has a rectangular shape. In some embodiments, the flexible housing 194 may have a square shape or other shapes. In some embodiments, the flexible housing 194 includes holes or openings to increase the flexibility of the RF coil assembly 180 (and the flexible housing 194). Each hole or opening may be radially located within the element 186. In some embodiments, the flexible housing 194 may contain a deformable material therein. The deformable material may include foam, memory foam, expandable foam, polyurethane foam, gels such as hydrogels, water balloons, or other suitable deformable materials. When a subject lies on the RF coil assembly 180, the subject will sink into the deformable material, and the RF coil 184 can conform to the unique shape of the subject and thus rest precisely against the patient's body. As depicted, an interface circuitry system 188 is disposed within the flexible housing 194. In some embodiments, the interface circuitry system 188 may be disposed outside the flexible housing 194.

[0053] As described above, each flexible coil element 186 can be constructed using wires (e.g., silver-plated copper wire). In some embodiments, each wire can be a bundle containing multiple conductive fibers.

[0054] Figure 3 This is a schematic cross-section of the conductive fiber 200, which can be used to form a coil element. The entire conductive fiber 200 is conductive. In some embodiments, the conductive fiber may be copper (e.g., silver-plated copper). As depicted, the conductive fiber 200 is exposed. No covering (dielectric material or shielding layer) is provided around the conductive fiber 200 itself.

[0055] Figure 4 It is a conductive fiber 210 that can be used to form coil elements (e.g., Figure 3 A schematic cross-section of a bundle 208 (e.g., a bare bundle) of conductive fibers 200. Bundle 208 includes multiple conductive fibers 210. The number of conductive fibers 210 in bundle 208 can be varied. No covering (e.g., dielectric material or shielding layer) is provided around bundle 208 itself.

[0056] Figure 5 This is a flowchart of method 212 for manufacturing an overmolded resonator for a radio frequency receiving coil assembly used in a magnetic resonance imaging system. Method 212 includes providing a pair of wires, wherein each of the pair of wires has a set desired (e.g., expected) length (box 214). In some embodiments, each wire may be made of copper (e.g., silver-plated copper). In some embodiments, each wire may be a bundle of conductive fibers. In some embodiments, the pair of wires may have different lengths. In some embodiments, the pair of wires may have the same length.

[0057] Method 212 further includes holding the pair of wires in a spatial arrangement fixed relative to each other (box 216). In some embodiments, the pair of wires can be held in a parallel arrangement at a fixed distance from each other using a forming device (e.g., made via micro-extrusion). The fixed distance can vary based on the desired characteristics of the coil elements. In some embodiments, the forming device can be made of a highly flexible, non-corrosive, inert, heat-resistant (e.g., up to 260 degrees Celsius) material with high dielectric strength. In some embodiments, the forming device is made of fluorinated ethylene propylene copolymer (FEP) or polytetrafluoroethylene (PTFE). In some embodiments, a clamping mechanism can be used to hold the pair of wires in a fixed spatial arrangement. In some embodiments, one or both ends of the respective wires can be axially offset from one or both ends of the other wire in the pair.

[0058] In some embodiments, method 212 includes (before overmolding) cutting at least one of the at least one wires while retaining it (box 218). In some embodiments, only one wire is cut (or slotted) once or more. In some embodiments, each wire is cut (or slotted) once or more. The spatial arrangement of cuts or notches relative to each other on the same wire and / or on another wire can vary based on the desired characteristics of the coil element.

[0059] Method 212 further includes overmolding a dielectric material over the pair of conductors (e.g., forming an overmolded conductor assembly) (box 220). The dielectric material may be rubber, plastic, or some other dielectric material (e.g., FEP or PTFE). In embodiments where one or more of the conductors in the pair include notches or cuts (e.g., forming wire segments), the dielectric material fills the corresponding spaces created by the cuts or notches. The overmolded wires and / or spaced-apart wire segments form an overmolded resonator. In some embodiments, overmolding includes overmolding additional features onto an overmolded member disposed over the pair of conductors. In some embodiments, overmolding of the additional features may be a separate overmolding performed after box 220. In some embodiments, the additional features may include corresponding strain relief members located at corresponding ends of the overmolded conductor assembly, wherein the corresponding strain relief members are configured to snap into a feed plate of an electronics unit. The additional features may include other shapes disposed at one or more locations along the length of the overmolded conductor assembly.

[0060] In some embodiments, method 212 further includes performing additional processing on the overmolded wire assembly (block 222). In some embodiments, this additional processing includes heat shrinking. In some embodiments, the additional processing includes trimming the length of the exposed ends of the wires extending from the overmolded wire assembly. Method 212 further includes coupling the pair of wires to an electronic unit (block 224).

[0061] Figure 6 This is a flowchart of method 226 for (e.g., using a forming device) overmolding a resonator for a radio frequency receiving coil assembly for a magnetic resonance imaging system. Method 226 includes placing each of a pair of wires into a corresponding reservoir of the forming device (box 228). Each of the pair of wires has a predetermined desired length. The forming device holds the pair of wires in a parallel arrangement, spaced a fixed distance from each other. The fixed distance may vary based on desired characteristics of the coil elements. In some embodiments, each wire may be made of copper (e.g., silver-plated copper). In some embodiments, each wire may be a bundle of conductive fibers. In some embodiments, the pair of wires may have different lengths. In some embodiments, the pair of wires may have the same length. In some embodiments, the forming device is prepared by micro-extrusion. In some embodiments, the forming device may be made of a highly flexible, resistant to most corrosive substances, inert, heat-resistant (e.g., up to 260 degrees Celsius), and high dielectric strength material. In some embodiments, the forming device is made of FEP or PTFE. In some implementations, one or both ends of the respective conductors may be axially offset from one or both ends of the other conductor in the pair.

[0062] In some embodiments, method 226 includes (before overmolding) cutting at least one of the at least one wires while retaining it (box 230). In some embodiments, only one wire is cut (or slotted) once or more. In some embodiments, each wire is cut (or slotted) once or more. The spatial arrangement of cuts or notches relative to each other on the same wire and / or on another wire can vary based on the desired characteristics of the coil element.

[0063] Method 226 further includes a shaper (box 232) that torsionally holds the pair of wires. In some embodiments, a slow linear torsion (e.g., approximately 90 or 180 degrees every 5 centimeters) is applied to better bend along both axes.

[0064] Method 226 further includes overmolding a dielectric material over the pair of conductors (e.g., forming an overmolded conductor assembly) (box 234). The dielectric material may be rubber, plastic, or some other dielectric material (e.g., FEP or PTFE). In embodiments where one or more of the conductors in the pair include notches or cuts (e.g., forming wire segments), the dielectric material fills the corresponding spaces created by the cuts or notches. The overmolded wires and / or spaced-apart wire segments form an overmolded resonator. In some embodiments, overmolding includes overmolding additional features onto an overmolded member disposed over the pair of conductors. In some embodiments, overmolding of the additional features may be a separate overmolding performed after box 234. In some embodiments, the additional features may include corresponding strain relief members located at corresponding ends of the overmolded conductor assembly, wherein the corresponding strain relief members are configured to snap into a feed plate of an electronics unit. The additional features may include other shapes disposed at one or more locations along the length of the overmolded conductor assembly.

[0065] In some embodiments, method 226 further includes performing additional processing on the overmolded wire assembly (block 236). In some embodiments, this additional processing includes heat shrinking. In some embodiments, the additional processing includes trimming the length of the exposed ends of the wires extending from the overmolded wire assembly. Method 226 further includes coupling the pair of wires to an electronic unit (block 238).

[0066] Figure 7 This is a flowchart of method 240 for manufacturing an RF receiver coil assembly with an overmolded resonator. Method 240 includes manufacturing a coil element or ring with an overmolded resonator, such as... Figure 5 Method 212 or Figure 6 Method 240 is described in method 226 (box 242). Method 240 also includes coupling the corresponding electronic units of the coil element to the electrical connector interface or interface circuit system 188 (e.g., a balun, such as an integrated balun cable harness that can act as an RF notch filter) via a corresponding coil interface connection cable (box 244). Method 240 further includes housing the coil element within a flexible housing (box 246).

[0067] Figure 8 This is a schematic diagram of the overmolded wire assembly 248. The overmolded wire assembly 248 utilizes... Figure 5 Method 212 or Figure 6The method 226 described above is used to manufacture the conductor assembly 248. The overmolded conductor assembly 248 includes a pair of conductors 250. Each conductor 250 in the pair has a correspondingly set desired (e.g., desired) length 252, 254. In some embodiments, each conductor 250 may be made of copper (e.g., silver-plated copper). In some embodiments, each conductor 250 may be a bundle of conductive fibers. As depicted, the pair of conductors 250 may have different lengths 252, 254. In some embodiments, the pair of conductors 250 may have the same lengths 252, 254. The pair of conductors 250 is overmolded with a dielectric material 256 (e.g., an insulator). The dielectric material 256 may be rubber, plastic, or some other dielectric material (e.g., FEP or PTFE). The pair of conductors 250 are arranged in a spatially fixed arrangement relative to each other at a fixed distance 258 from each other. In some embodiments, the pair of conductors 250 may be held in a parallel arrangement at a fixed distance 258 from each other using a forming device (e.g., manufactured via micro-extrusion). The fixed distance 258 can vary based on the desired characteristics of the coil elements. The formwork can also be overmolded with dielectric material 256. As depicted, one or both ends 260 of the respective wires 250 can be axially offset (in the axial direction 262) from one or both ends 260 of the other wire 250 in the pair of wires 250. As depicted, the ends 260 of the wires 250 extend beyond the overmolded dielectric material 256 of the overmolded wire assembly 248.

[0068] Figure 9 This is a schematic diagram of an overmolded wire assembly 264 (e.g., having overmolded additional features). The overmolded wire assembly 264 utilizes... Figure 5 Method 212 or Figure 6 Method 226 is used to manufacture the in-situ wire assembly. The overmolded wire assembly 264 is as follows: Figure 8 As described in [the text]. Furthermore, the overmolded wire assembly 264 includes additional features 266 overmolded thereon. For example, the overmolded wire assembly 264 includes corresponding strain relief members 268 located at corresponding ends 270, 272 of the overmolded wire assembly 264, wherein the corresponding strain relief members 268 are configured to snap onto an electronic unit (e.g., [the electronic unit]). Figure 2 The additional feature 266 may include other shapes disposed at one or more locations along the length of the overmolded wire assembly 264. As depicted, the additional feature 274 is centrally located on the overmolded wire assembly 264.

[0069] Figure 10This is a schematic diagram of an overmolded wire assembly 276 (e.g., having overmolded additional features and a torsion portion). The overmolded wire assembly 276 utilizes... Figure 5 Method 212 or Figure 6 Method 226 is used to manufacture the in-situ wire assembly. The overmolded wire assembly 276 is as follows: Figure 9 As described herein. Additionally, the pair of conductors are twisted in the axial direction 262. In some embodiments, the overmolded conductor assembly 276 has a former that is also twisted in the circumferential direction along the axial direction 262. The twisting can be a slow, linear twist in the overmolded conductor assembly 276 (e.g., approximately 90 or 180 degrees per 5 cm) to better bend along both axes. The amount and rate of twisting can vary based on the desired characteristics of the coil elements.

[0070] Figure 11 This is a schematic diagram of an overmolded wire assembly 278 (e.g., having overmolded additional features, notches, and twists). The overmolded wire assembly 278 utilizes... Figure 5 Method 212 or Figure 6 Method 226 is used to manufacture the in-situ wire assembly. The overmolded wire assembly 276 is as follows: Figure 10 As described herein. Additionally, at least one of the conductors includes a cut or notch 280. An additional feature 274 is located around the cut or notch. An overmolded portion of dielectric material 256 fills the cut or notch 280.

[0071] Figure 12 It is an overmolded wire assembly 278 (e.g., such as Figure 11 A schematic diagram of the coupling between end 270 (as described in the diagram) and electronic unit 185. Electronic unit 185 includes a feed board 282 (e.g., a printed circuit board). As depicted, electronic unit 185 includes a reservoir 284 to receive end 270 (and) of the overmolded wire assembly 278. Figure 11 End 272 of the wire 250 is coupled to a reservoir 284 on a feed plate 282. A strain relief element 268 is configured to snap into the reservoir 284 on the feed plate 282 to couple the end 270 of the overmolded wire assembly 278 to the electronics unit 185. The corresponding ends 260 of the wires 250 are then brazed to corresponding conductive pads 286 on the feed plate 282 adjacent to the reservoir 284. The overmolded wire assembly 278 is coupled to the electronics unit 185 to form a coil element (e.g., a loop).

[0072] Figure 13This is a schematic diagram of the longitudinal end 288 of the former 290. The former 290 includes a reservoir 292 for receiving a pair of wires. When placed in the reservoir 292, the former 290 holds the pair of wires in a parallel arrangement at a fixed distance from each other. The fixed distance can vary based on the desired characteristics of the coil elements. The former 290 can be manufactured via micro-extrusion. The shape and size of the former 290 can vary. In some embodiments, the former 290 can be made of a highly flexible, non-corrosive, inert, heat-resistant (e.g., up to 260 degrees Celsius) material with high dielectric strength. In some embodiments, the former 290 is made of fluorinated ethylene propylene copolymer (FEP) or polytetrafluoroethylene (PTFE). In an exemplary embodiment, the former 290 is made of PTFE. The respective edges 294 of the reservoir 292 include features 296 configured to hold a respective wire of the pair of wires. Feature 296 extends in the circumferential direction 298 (opposite to the radial direction) relative to the longitudinal axis 300 of the forming device 290.

[0073] Figure 14 It is to maintain a pair of wires at 250. Figure 13 A schematic diagram of the longitudinal end 288 of the forming device 290. As depicted, each wire 250 includes a bundle 302 of conductive fibers 304.

[0074] Figure 15 This is a schematic diagram of the longitudinal end 288 of the overmolded conductor assembly 306. As depicted, a dielectric material 308 is overmolded over the pair of conductors 250 and the formwork 290. As depicted, the dielectric material 308 extends into the reservoir 292 and is disposed around the conductors 250 in the reservoir 292. The dielectric material 308 may be rubber, plastic, or some other dielectric material (e.g., FEP or PTFE). In an exemplary embodiment, the dielectric material 308 is FEP.

[0075] Figure 16 This is a perspective view of the overmolded lead assembly 310. The overmolded lead assembly 310 includes a pair of leads disposed with a formor 290 and overmolded with a dielectric material 308, as described above. As depicted, the formor 290 is twisted along the axial direction 262 relative to the longitudinal axis 300 of the formor 290 in the circumferential direction 298. The twisting can be a slow linear twist in the overmolded lead assembly 310 (e.g., approximately 90 degrees every 5 cm) to better bend along both axes. The amount and rate of twisting can vary based on the desired characteristics of the coil elements.

[0076] Figure 17 This is a schematic diagram of the longitudinal end 312 of a wire assembly 314 with a first fixed distance 316 between the wires 250. Figure 18 This is a schematic diagram of the longitudinal end 318 of an overmolded wire assembly 320 having a second fixed distance 322 between the wires 250. The overmolded wire assembly 314 is as described above. Specifically, for each overmolded wire assembly 314, 320, a pair of wires 250 is provided with a corresponding reservoir 292 of a forming device 290. Dielectric material 308 is overmolded over the pair of wires 250 and the forming device 290. The wires 250 have a diameter 324 (e.g., 0.40 mm). As depicted, the diameter 324 of each wire 250 in the pair of wires 250 is the same. As depicted, the diameter 324 of the wires 250 in different overmolded wire assemblies 314, 320 is the same. In some embodiments, the diameter 324 of the wires 250 in different overmolded wire assemblies 314, 320 may vary based on the desired characteristics of the coil element. As depicted, the second fixed distance 322 (e.g., 0.489 mm) is greater than the first fixed distance 316 (e.g., 0.108 mm). The fixed distances can vary based on the desired characteristics of the coil elements. The forming element 290 in the overmolded conductor assembly 314 has a diameter 326. The forming element 290 in the overmolded conductor assembly 320 has a diameter 328. The overmolded conductor assembly 314 has a diameter 330. The overmolded conductor assembly 320 has a diameter 332. Because the second fixed distance 322 is greater than the first fixed distance 316, diameters 328 and 332 are greater than diameters 326 and 330, respectively. The overmolded conductor assembly 314 has a pitch 334 (e.g., the distance between the centers of the pair of conductors 250). The overmolded conductor assembly 320 has a pitch 336 (e.g., the distance between the centers of the pair of conductors 250). The pitch 336 (e.g., 0.889 mm) is greater than the pitch 334 (e.g., 0.508 mm). In some embodiments, the fixed distance between a pair of conductors in the overmolded conductor assembly can vary between 0.108 mm and 0.489 mm. The pitch can be 0.40 mm larger than the fixed distance of the overmolded conductor assembly. Therefore, in some embodiments, the pitch of the overmolded conductor assembly can vary between 0.508 mm and 0.889 mm.

[0077] Figure 19 This is a perspective view of a portion of the forming device 338. The forming device 338 is similar to... Figure 13 The forming device 290 is depicted in the figure. However, the corresponding edge 294 of the reservoir 292 of the forming device 338 extends in the radial direction 340 relative to the longitudinal axis 300 of the forming device 338. Figure 19As depicted, each reservoir 292 includes an inner surface 342. Each reservoir 292 includes a distance 344 (e.g., 0.40 mm) between the inner surfaces 342 of its edges 294. Each reservoir 292 also includes a distance or pitch 346 (e.g., 0.265 mm) from the portion of the reservoir 292 closest to the longitudinal axis 300 to the outermost portion of the edge 294 in the radial direction 340.

[0078] Figure 20 It has Figure 19 A schematic diagram of the longitudinal end 348 of the overmolded conductor assembly 350 in the forming device 338. A pair of conductors 250 (e.g., each conductor having multiple conductive fibers) are disposed within a reservoir 292 of the forming device 338. Dielectric material 352 is overmolded over the conductors 250 and the forming device 338. The conductors 250 have a diameter 354 (e.g., 0.4 mm). The pitch 356 between the centers of the conductors 250 is 0.665 mm. The overmolded conductor assembly 350 may include additional insulation 358, thereby giving the overmolded conductor assembly 350 a height 360 of 1.105 mm and a width 362 of 2.019 mm.

[0079] The technical effects of the disclosed embodiments include enabling the creation of assemblies (e.g., overmolded conductor assemblies) with desired lengths and dielectric overmolding features. The technical effects of the disclosed embodiments also include providing a more static method or process for more precisely setting lines in the dielectric material (i.e., controlling line spacing). The technical effects of the disclosed embodiments further include enabling advanced features (e.g., strain relief elements) to be overmolded thereon, providing a robust and simple interface connection to the feedboard of the electronic unit. The technical effects of the disclosed embodiments even further include providing slow linear torsion (e.g., approximately 90 or 180 degrees per 5 centimeters) in the assembly for better bending along both axes. The technical effects of the disclosed embodiments still further include providing a more reliable method for manufacturing resonators for RF coils.

[0080] Referring to the technology presented herein and protected by the claims, and applying it to physical objects and concrete examples of practical nature, which explicitly improves the present art, and therefore is not abstract, intangible, or purely theoretical. Furthermore, if any claim appended to the end of this specification contains one or more elements designated as “means for [performing]…” or “steps for [performing]…”, such elements are intended to be interpreted according to 35U.SC112(f). However, for any claim containing elements designated in any other way, such elements are not intended to be interpreted according to 35U.SC112(f).

[0081] This disclosure also provides support for a method of overmolding a resonator for manufacturing a radio frequency receiving coil assembly for a magnetic resonance imaging system, the method comprising: providing a pair of wires, wherein each of the pair of wires has a predetermined desired length; holding the pair of wires in a spatial arrangement fixed relative to each other; overmolding a dielectric material over the pair of wires to form an overmolded wire assembly; and coupling the pair of wires to an electronic unit. In a first example of the method, the method further comprises placing each of the pair of wires into a corresponding reservoir of a forming device, wherein the forming device holds the pair of wires in a parallel arrangement spaced a fixed distance from each other. In a second example of the method, optionally including the first example, the method further comprises overmolding the dielectric material over the pair of wires and the forming device. In a third example of the method, optionally including one or both of the first and second examples, the method further comprises: wherein the forming device is made of a chemically inert and flexible material. In a fourth example of the method, optionally including one or more of the first to third examples, the method further comprises: twisting the forming device holding the pair of wires before overmolding with the dielectric material. In a fifth example, which optionally includes one or more of the methods from the first to the fourth examples, the corresponding outer edge of each reservoir of the molding device includes a feature for clamping a corresponding wire in the pair of wires. In a sixth example, which optionally includes one or more of the methods from the first to the fifth examples, the overmolded resonator has distributed capacitance. In a seventh example, which optionally includes one or more of the methods from the first to the sixth examples, the method further includes cutting at least one wire in the pair of wires while holding it in place before overmolding with the dielectric material. In an eighth example, which optionally includes one or more of the methods from the first to the seventh examples, the overmolding includes overmolding an additional feature onto an overmolded member disposed above the pair of wires. In a ninth example, which optionally includes one or more of the methods from the first to the eighth examples, the additional feature includes a corresponding strain relief member located at a corresponding end of the overmolded wire assembly, wherein the corresponding strain relief member is configured to snap into the feed plate of the electronic unit.

[0082] This disclosure also provides support for a method of manufacturing an overmolded resonator for a radio frequency receiving coil assembly for a magnetic resonance imaging system, the method comprising: placing each of a pair of wires into a respective reservoir of a molding apparatus, wherein each of the pair of wires has a predetermined desired length, and the molding apparatus holds the pair of wires in a parallel arrangement spaced a fixed distance from each other; overmolding a dielectric material over the pair of wires and the molding apparatus to form an overmolded wire assembly; and coupling the pair of wires to an electronic unit. In a first example of the method, the molding apparatus is made of a chemically inert and flexible material. In a second example of the method, optionally including the first example, the method further comprises: twisting the molding apparatus holding the pair of wires before overmolding with the dielectric material. In a third example of the method, optionally including one or both of the first and second examples, a respective outer edge of each reservoir of the molding apparatus includes features for clamping a respective wire of the pair of wires. In a fourth example of the method, optionally including one or more of the first to third examples, the overmolded resonator has distributed capacitance. In a fifth example, which optionally includes one or more of the first to fourth examples, the method further includes cutting at least one wire while it is held by the forming device before overmolding with the dielectric material. In a sixth example, which optionally includes one or more of the first to fifth examples, the overmolding includes overmolding an additional feature onto an overmolded member disposed above the pair of wires. In a seventh example, which optionally includes one or more of the first to sixth methods, the additional feature includes a corresponding strain relief member located at a corresponding end of the overmolded wire assembly, wherein the corresponding strain relief member is configured to snap into the feed plate of the electronic unit.

[0083] This disclosure also provides support for a radio frequency (RF) receiver coil assembly for a magnetic resonance imaging system, the RF receiver coil assembly comprising: an RF coil including a plurality of loops, each loop including a covered conductor assembly having a plurality of covered resonators, each covered conductor assembly including a pair of conductors, each conductor disposed in a respective reservoir of a forming device, each conductor in the pair having a predetermined desired length, the forming device holding the pair of conductors in a parallel arrangement spaced a fixed distance from each other, and a dielectric material being covered over the pair of conductors and the forming device. In a first example of the RF receiver coil assembly, each covered conductor assembly includes a respective strain relief member covered at a respective end of the covered conductor assembly, wherein the respective strain relief member is configured to snap into a feed plate of an electronics unit.

[0084] This written description uses examples to disclose the invention, including the best mode, and also enables any person skilled in the art to practice the invention, including making and using any device or system and performing any included methods. The scope of the invention is defined by the claims and may include other examples that would occur to a person skilled in the art. Such other examples are intended to fall within the scope of the claims if they have structural elements that are not indistinguishable from the literal language of the claims, or if they include equivalent structural elements that have minor differences from the literal language of the claims.

Claims

1. A method for manufacturing an overmolded resonator for a radio frequency receiving coil assembly (180) for a magnetic resonance imaging system (100), the method comprising: A pair of wires (250) are provided, wherein each of the pair of wires (250) has a set desired length; The pair of conductors (250) are held in a spatial arrangement that is fixed relative to each other; A dielectric material (256) is overmolded over the pair of conductors (250) to form an overmolded conductor assembly (248); and The pair of wires (250) are coupled to the electronic unit (185).

2. The method according to claim 1, the method further comprising placing each of the pair of conductors (250) into a corresponding reservoir of the forming device (290), wherein the forming device (290) holds the pair of conductors (250) in a parallel arrangement at a fixed distance from each other.

3. The method according to claim 2, the method further comprising overmolding the dielectric material (256) over the pair of conductors (250) and the forming device (290).

4. The method according to claim 2, wherein the forming device (290) is made of a chemically inert and flexible material.

5. The method according to claim 2, the method further comprising twisting the forming device (290) that holds the pair of conductors (250) prior to overmolding with the dielectric material (256).

6. The method according to claim 2, wherein the respective outer edge of each reservoir of the forming device (290) includes a feature (296) for clamping the respective wire (250) of the pair of wires (250).

7. The method of claim 1, wherein the overmolded resonator has distributed capacitance.

8. The method according to claim 1, the method further comprising cutting the at least one wire (250) while retaining at least one of the pair of wires (250) before overmolding with the dielectric material (256).

9. The method of claim 1, wherein overmolding comprises overmolding additional features onto an overmolded part disposed above the pair of conductors (250).

10. The method of claim 9, wherein the additional feature includes a corresponding strain relief member (268) located at a corresponding end of the overmolded conductor assembly (248), wherein the corresponding strain relief member (268) is configured to snap into the feed plate of the electronic unit (185).

11. A method for manufacturing an overmolded resonator for a radio frequency receiving coil assembly (180) for a magnetic resonance imaging system (100), the method comprising: Each of a pair of wires (250) is placed into a corresponding reservoir of a forming device (290), wherein each of the pair of wires (250) has a set desired length, and the forming device (290) holds the pair of wires (250) in a parallel arrangement at a fixed distance from each other. A dielectric material (256) is overmolded over the pair of conductors (250) and the forming device (290) to form an overmolded conductor assembly (248); and The pair of wires (250) are coupled to the electronic unit (185).

12. The method of claim 11, wherein the forming device (290) is made of a chemically inert and flexible material.

13. The method of claim 11, the method further comprising twisting the forming device (290) that holds the pair of conductors (250) prior to overmolding with the dielectric material (256).

14. The method according to claim 11, wherein the respective outer edge of each reservoir of the forming device (290) includes a feature (296) for clamping a respective wire (250) of the pair of wires (250).

15. The method of claim 11, wherein the overmolded resonator has distributed capacitance.

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