Flexible Magnetic Resonance (MR) Coil Array Using Electrical Zipper Contacts

Abstract

The magnetic resonance (MR) coil construction system includes an MR coil sheet 20 including conductive MR coil elements or MR coil element portions 22 disposed on an electrically insulating sheet 26. The MR coil sheet includes edges having connection mechanisms 34, 48 configured to connect the MR coil sheets to construct an MR coil array 44.

Description

[Technical field]

[0001] The following relates generally to the magnetic resonance (MR) imaging, MR coil array, MR coil array assembly, MR coil construction, and related technologies. [Background technology]

[0002]

[0002] MR coil arrays consisting of multiple coil elements are becoming more and more popular because they can achieve parallel imaging data acquisition and, as a result, faster data acquisition and / or higher image resolution and / or higher SNR (signal-to-noise ratio). MR receive coil arrays with multiple coil elements employ many channels for parallel acquisition, e.g., one channel per coil element. Summary of the Invention [Problem to be solved by the invention]

[0003]

[0003] However, it is difficult to develop a "one size fits all" coil array that is suitable for use with patients of various sizes, girths, or other body-specific considerations. Therefore, MR imaging laboratories usually need to stock a set of MR coil arrays (e.g., torso coil arrays) for the specific anatomies of patients of various sizes and shapes. This is costly. Also, if an imaging technician selects a coil array that is poorly suited to a particular patient, this can degrade the quality of the acquired MR images. [Means for solving the problem]

[0004]

[0004] Several improvements are disclosed below.

[0005] In some embodiments disclosed herein, an MR coil construction system includes an MR coil sheet including conductive MR coil elements or MR coil element portions disposed on an electrically insulating sheet, the MR coil sheet including edges with connection mechanisms configured to connect the MR coil sheets to construct an MR coil array.

[0006]

[0006] In some embodiments disclosed herein, an MR coil array comprises MR coil sheets, each MR coil sheet comprising at least one conductive MR coil element or MR coil element portion disposed on an electrically insulating sheet with at least one edge including a tooth. One or more zippers secure the MR coil sheets together to form the MR coil array, each zipper formed by interlocking teeth on adjacent edges of different MR coil sheets of the MR coil array.

[0007]

[0007] In some embodiments disclosed herein, a method of constructing an MR coil array includes connecting MR coil sheets having conductive MR coil elements or MR coil element portions to each other using edge connectors to construct an MR coil array.

[0008] One advantage is the ability to provide a highly configurable MR coil array.

[0009] Another advantage is that an MR coil array can be provided that allows for improved signal-to-noise ratio (SNR) by locating the metal conductor loops closer to the patient.

[0010] Another advantage is in an MR coil array with a zipper assembly that provides a geometrically fixed spatial relationship between coil elements in adjacent sheets.

[0011] Another advantage resides in providing an MR coil array with a zipper assembly that provides a visually perceptible positive pole connection between the coil sheets that make up the constructed MR coil array.

[0012] Another advantage is that it allows detuning of the MR coil array by partially unzipping the coil sheet from the coil array.

[0013]

[0013] A given embodiment may provide none of the above-mentioned advantages, or may provide one, two, more, or all of the above-mentioned advantages, and / or may provide other advantages, as would be apparent to one of ordinary skill in the art upon reading and understanding this disclosure.

[0014]

[0014] The invention takes form in various components and arrangements of components, and in various steps and arrangements of steps. The drawings are only for purposes of illustrating preferred embodiments and are not to be construed as limiting the invention. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 illustrates a magnetic resonance (MR) imaging device with an MR coil array according to the present disclosure. [Diagram 2]

[0016] FIG. 1 illustrates components of an MR coil array according to an embodiment employing optical fibers for transferring MR signals from the MR coil array. [Diagram 3]

[0017] FIG. 2 is a diagram showing a method for constructing the coil array of FIG. 1. [Figure 4]

[0018] FIG. 2 illustrates an embodiment of the MR coil array of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016]

[0019] In the following, a flexible coil configuration is disclosed in which a flexible coil sheet with zippered edges can be selectively connected to form a coil array of a desired size. In some examples, the zipper is composed of mostly non-conductive teeth, but includes a few conductive teeth for making galvanic electrical connections between coil elements in adjacent coil sheets. In other examples, an additional connecting link cable is required in certain clinical applications to make electrical connections between adjacent coil elements. It is contemplated that the coil sheet is made of a lightweight foam housed in a plastic jacket, the foam including recesses, for example, with gold-plated copper coil elements inside. The non-conductive teeth of the zipper can be a hard plastic, while the conductive teeth need to be a non-magnetic material, contemplated here to be a gold-plated copper alloy. Also, from a radio frequency (RF) quality standpoint, it is preferable to have a preamplifier for the RF channel built into the coil sheet, although lower image quality may be acceptable for some applications.

[0017]

[0020] In some alternative embodiments, the zipper may include a toothless continuous zipper of the type used in applications where it is desirable for a zipper to create an airtight seal (e.g., freezer bags for storing frozen foods), or the zipper may be replaced by another edge-to-edge fastener arrangement, such as a snap.

[0018]

[0021] If the number of RF channels is sufficient, more coil elements can be added by adding one or more additional coil sheets to accommodate patients with (for example) larger girths. On the other hand, if the number of RF channels is limited, larger coil sheets with larger coil elements can be used to accommodate larger girths without increasing the number of RF channels used by the coil. As another variation, the selection of coil sheets for use with a particular patient / procedure combination is based on the density of the coil elements. For example, if it is desired to perform higher resolution imaging on the right side of the body, a coil sheet with a higher density of coil elements is used on the right side of the assembled coil array rather than on the left side.

[0019]

[0022] In some examples, the zipper may include mutually parallel zippers extending along a transverse direction, allowing size adjustment in only one dimension, although the zipper may include a two-dimensional array of zippers (possibly with some conductive teeth in only one direction).

[0020]

[0023] The resulting MR coil array may be wired or wireless. In one embodiment, the coils are attached to the base via zipper edges of the outermost coil sheets of the assembled (i.e., "zipped together") coil array. Instead of the base, the connecting zippers may be built into the patient bed. These zipper terminal connections may be galvanic, but if the RF processing of the on-coil sheets includes conversion to optical signals, the zipper terminal connections may be in the form of optical couplers. In another example, the connected coils (e.g., via zippers) are local coils (e.g., anterior coils on the patient's chest) placed on the patient, and the local coils may be connected to an interface built into the patient table via zippers (rather than mechanical plugs). In the case of a wireless MR coil array, the coil sheets (or some subset thereof) preferably include radio or infrared transmitters or transceivers for transferring MR signals from the coil array. In this case, the coil array does not need to be attached to a base or the like (e.g., the coil array may be placed on the patient without wired signal connections). It is further contemplated that sensors (e.g., heart rate, temperature) may be incorporated into the coil sheets, and if so, the conductive teeth may provide galvanic electrical connections for these sensors. Although the disclosed configurable MR coil array employing coil sheets zip-connected to one another is primarily intended for MR receive coil arrays, it may also be used to construct MR transmit coil arrays or MR transceiver coil arrays. In this case, the base or other electrical connections preferably include an RF power input connection for delivering RF power to the MR coil array during the transmit phase of an MR imaging sequence.

[0021]

[0024] The design disclosed herein has significant advantages, most notably the high degree of configurability of the assembled coil. It also allows for improved signal-to-noise ratio (SNR) by placing metal conductor loops closer to the patient. Using zippers to connect coil sheets to form an MR coil array provides a geometrically fixed spatial relationship between coil elements of adjacent sheets, allowing imaging technicians to visually verify the positive pole connection between coil sheets. An additional advantage is that the coil array can be detuned by isolating specific coils, for example, by opening zippers on parts of the coil array (although this can also be done electronically, for example, by isolating diodes). Coil elements that interfere with each other can be identified during pre-test RF testing.

[0022]

[0025] In a further aspect, it is contemplated to provide automatic or semi-automatic assistance to the MR imaging technician in selecting coil sheets for forming the MR coil array. Some MRI scanners are equipped with a three-dimensional (3D) camera, so that the patient can be imaged with the 3D camera during patient transport. Based on the image data and other important information such as the number of available RF channels and the intended imaging procedure, an artificial intelligence (AI) program can estimate the optimal configuration of coil sheets for the patient and show this configuration to the imaging technician. In one embodiment, it is contemplated to display a graphical rendering of the proposed configured MR coil array including the coil sheets and their zipper connections, which is particularly useful for 2D zipper embodiments where there are many possible configurations. In a simpler implementation, which may be more suitable for parallel zipper-only torso or abdominal coils, measurements of the torso and / or abdomen can serve as input for the AI ​​program instead of the 3D image.

[0023]

[0026] With reference to FIG. 1, an exemplary magnetic resonance (MR) imaging device 10 comprises a magnetic resonance (MR) imaging scanner, which in an exemplary example comprises a housing or gantry 12 that includes various components not shown in FIG. 1, including, by way of non-limiting illustrative example, a superconducting or resistive magnet for generating a static (B0) magnetic field, magnetic field gradient coils for superimposing magnetic field gradients on the B0 field, a whole-body radio frequency (RF) coil for applying RF pulses to excite and / or spatially encode magnetic resonance in an imaging subject disposed in an MR bore 14 or other MR examination region, etc. A robotic patient couch 16 or other subject support allows a medical patient, subject undergoing medical screening, or other imaging subject to be transported into the MR bore 14 for imaging. As will be further described, MR imaging employs an MR coil array 44.

[0024]

[0027] With continued reference to FIG. 1, an exemplary MR coil array 44 is made up of four coil sheets 20 whose edges are connected together with a zipper. Each MR coil sheet 20 forms a portion of the MR coil array 44. Although the MR coil array 44 made up of four MR coil sheets 20 is shown in FIG. 1, any suitable number of MR coil sheets may be similarly combined with zippered edges to form a configurable MR coil array with a selected number of coil elements 22. The lower portion of FIG. 1 shows a plan view of the MR coil array 44 made up of the exemplary four coil sheets 20. Each MR coil sheet 20 includes one or more coil elements and / or portions of coil elements 22 (21 of which are shown in FIG. 1) adapted to receive MR signals, and an electronic module 24 (illustrated as a solid box) is operably connected to receive and pre-amplify, and optionally further process (e.g., digitize) the MR signals received by the coil elements 22. 1 shows the MR coil array 44 with fifteen coil elements 22 in a 3×5 array, it should be appreciated that this arrangement is merely an illustrative example and that more or less than fifteen coil elements may be used in various arrangements. For example, as some further non-limiting illustrative examples, a wireless MR coil may include a one-dimensional arrangement (i.e., a linear array) of four or more coil elements, a two-dimensional arrangement of N·M coil elements arranged in a regular N×M array (in the illustrative case of the wireless MR coil 20, N=3 and M=5, so N·M=15), or a two-dimensional arrangement of coil elements that are not arranged in a regular N×M array.

[0025]

[0028] Each coil sheet 20 includes its own insulating sheet 26 that forms structural support for the MR coil array 44 when the coil sheets are zip-connected to one another. In some examples, the electrical insulating sheet 26 includes lightweight foam encased in a plastic jacket. It should be understood that the MR coil array 44 with efficient and configurable communication connectivity as disclosed herein may be construed as having a wide variety of suitable physical layouts or configurations. In general, the MR coil array 44 may be constructed as having any suitable configuration for a selected type of imaging. For example, an exemplary MR coil may have the shape of a sheet and be placed on, in, or under a pallet (not shown) placed on the subject couch 16 to perform imaging of, for example, the spine, torso, etc. Alternatively, the wireless MR coil may be shaped to encircle the head (i.e., head coil), orbit the limbs (limb coil), etc.

[0026]

[0029] 1 also shows that the edges of the MR coil sheets 20 include connection features configured to connect with corresponding connection features 34 of other MR coil sheets 20. In one exemplary embodiment, the connection features 34 include continuous edge connectors configured to connect the MR coil sheets 20 by interlocking to define a toothless zipper.

[0027]

[0030] 1, the connection mechanism 34 comprises teeth configured to connect the MR coil sheets 20 by interlocking to define a zipper that connects the MR coil sheets 20 together to form the MR coil array 44. The teeth include non-conductive, i.e., electrically insulating teeth (illustrated in FIG. 1 as unfilled teeth) and conductive teeth 38 (illustrated in FIG. 1 as filled teeth). In one exemplary embodiment, the non-conductive teeth 36 are made of plastic and the conductive teeth 38 are made of a gold-plated copper alloy.

[0028]

[0031] The zippers 34 are used to connect multiple coil sheets 20 (four of which are shown in FIG. 1 ). When the coil sheets 20 are connected, they form an MR coil array 44. In other words, the coil sheets 20 comprise an MR coil construction system. In some examples, the connection mechanisms 34 extend parallel to each other in the transverse direction of the MR coil array 44. In other examples, the connection mechanisms 34 form an array of connection mechanisms distributed across the entire surface of the MR coil array 44 (i.e., two zippers 34 are either perpendicular to each other or parallel to each other). In other examples, when the MR coil array 44 is formed, the coil sheets 20 of the array can include zippers 34 with coil edge attachments 48 that include the edges of the MR coil sheets at the periphery of the MR coil array where the teeth 36, 38 are not interlocked with the teeth of any other MR coil sheet, allowing the array 44 to be connected to a different coil array (not shown). The MR coil sheet 20 includes conductive MR coil element portions configured to be galvanically connected to one another by conductive teeth 38. This allows the coil array 44 to include overlapping coil elements, some of which extend across the zipper 34.

[0029]

[0032] 2, in some embodiments, the electronic module 24 includes an electro-optical transducer 28 (e.g., an LED (not shown)) that converts the received MR signal into an optical signal. For example, the MR signal from the coil element 22 is received in the electronic module 24, which includes a preamplifier PRE that preamplifies the MR signal, an analog-to-digital converter ADC that digitizes the preamplified MR signal, and an optical transducer TD, such as an LED, that converts the digitized MR signal into an optical pulse. In another example, the electronic module 24 may include a suitable digital connection (e.g., LVDS, FDP 3 link, etc.) or a suitable analog connection. The electronic module 24 is connected to an optical fiber 31 that carries the optical pulse. In this case, the optical fiber 31 is for connection with a second optical fiber 32 in another coil sheet. Thus, the connecting zipper may include an optical coupling 30 formed by interlocking optical coupler teeth 38', 39' interspersed with optically inactive teeth 36 of a zipper 34 of an MR coil array 44 (see inset A in FIG. 2). As shown in FIG. 2, an optical fiber 31 connects to an optical fiber 32 through the zipper 34 by a first tooth 38' connected to the transmitting optical fiber 31, which serves to transmit the optical signal, and a second tooth 39' of a different coil sheet, which is connected to the optical fiber 32 and receives the optical signal transmitted by the tooth 38'. The teeth 38', 39' are pressed against each other by the zipping process to achieve physical adjacency and facilitate the transfer of light from tooth 38' to tooth 39'.

[0030]

[0033] 1, it is contemplated to provide a way to automatically recommend a particular coil array configuration for a particular patient. To that end, one or more sensors are provided that are configured to measure patient characteristics of the patient. In one exemplary embodiment, the sensor comprises a camera 46 (e.g., a three-dimensional (3D) camera) configured to acquire images of the patient during patient transfer into the bore 14 of the MR imaging device 12.

[0031]

[0034] In another example, the sensor may include one or more sensors 47 disposed on the coil array 44 adjacent the zipper 34 to determine if the zipper 34 is being used correctly. In some examples, each zipper 34 may include a corresponding sensor 47 (although only one sensor 47 is shown in FIG. 1 ). The zipper 34 must be fully (i.e., from start to finish) closed such that the teeth 36, 38 (or teeth 38′, 39′) are all engaged with one another. If the zipper 34 is not fully closed, the sensor 47 may generate a feedback signal (i.e., optical signal, acoustic signal, etc.) to the medical personnel assembling the coil array 44. The sensor 47 may also generate a feedback signal if the zipper 34 is accidentally opened during an imaging examination (e.g., due to movement of the patient's body on which the coil array 44 is placed, the coil array being pinched between the subject couch 16 and the patient and / or gantry 12, etc.).

[0032]

[0035] 1 also illustrates an electronic processing device 48, which may include a tablet, laptop computer, workstation computer, or more generally, a computer. The electronic processing device 48 includes typical components such as an electronic processor 50 (e.g., a microprocessor), at least one user input device 52 (e.g., a mouse, keyboard, trackball, touch screen, etc.), and at least one display device 54 (e.g., an LCD display, a plasma display, a cathode ray tube display, etc.). The electronic processor 50 is operatively connected to one or more non-transitory storage media 56. The non-transitory storage media 56 may include, for example, as non-limiting illustrative examples, one or more of a magnetic disk, RAID, or other magnetic storage medium, a solid state drive, a flash drive, an electronically erasable read-only memory (EEROM) or other electronic memory, an optical disk or other optical storage, or various combinations thereof, and may be, for example, network storage, an internal hard drive of the electronic processing device 48, or various combinations thereof, and the like. It should be understood that any reference herein to one or more non-transitory media 56 should be broadly interpreted as encompassing a single medium or multiple media of the same or different types. Similarly, the electronic processor 50 may be embodied as a single electronic processor or as two or more electronic processors. The non-transitory storage medium 56 stores instructions executable by the at least one electronic processor 50. The instructions include instructions for generating a graphical user interface (GUI) 58 for display on a display device 54 of the operating device. The electronic processor 50 also employs an artificial intelligence (AI) component 60 configured to output a recommended configuration of the MR coil array 40 by estimating a recommended configuration of the MR coil array 44 for a patient based on measured patient characteristics (e.g., measured by the camera 46).

[0033]

[0036] 3, an exemplary operation of constructing the MR coil array 44 is illustrated as a flow chart. In an operation 102, the camera 46 is configured to acquire a 3D image of a patient being transferred into the bore 14 of the MR imaging device 12. In an operation 104, performed by the electronic processing device 48, the electronic processor 50 is configured to process the 3D image of the patient and determine one or more patient characteristics (e.g., height, weight, waist circumference, etc.) by image processing performed on the 3D image. In an operation 106, performed by the electronic processing device 48, the determined characteristics are input to the AI ​​component 60, which outputs a proposed MR coil array configuration based on the determined characteristics. This configuration includes a grid of MR coil sheets 20. The proposed MR coil array configuration can be displayed in the GUI 58 of the display device 54.

[0034]

[0037] In a manual operation 108 (i.e., not performed by the electronic processing device 48), the MR coil sheet 20 comprising conductive MR coil elements or MR coil element portions 22 are connected using an edge connection mechanism 48 to construct the MR coil array 44 according to a configuration output by the AI ​​component 60 and displayed on the display device 54. The edge connection mechanism 48 comprises non-conductive interdigital teeth 36 and conductive interdigital teeth 38. The MR coil sheet 20 comprises conductive MR coil element portions configured to be galvanically connected to each other by the conductive interdigital teeth.

[0035]

[0038] In another, more manual embodiment, operation 102 is omitted, operation 104 includes manual acquisition of patient characteristics, such as manual measurement of torso and / or waist circumference using a tape measure, and operation 106 determines a recommended coil array configuration based on the measurements acquired in operation 104. Here, operation 106 may be performed by electronic processing device 48, for example, after receiving typed input of the torso and / or waist measurements, or may be performed manually using a printed table listing recommended coil array configurations for various waist and / or torso measurements.

[0036]

[0039] A typical coil element comprises a first and a second part. The first part contains electronics such as preamplifiers and detuning electronics. This first part may be connected to the MR system via a cable (e.g., optical, galvanic, or both) or the connection may be wireless. This coil part is standalone and is connected to a second part of the coil element. The second part of the coil element contains only radio frequency (RF) coil elements. The second part of the coil may be discarded or replaceable if it fails. The second part is relatively inexpensive and requires service or replacement after a certain number of uses. The first part is much more expensive and may be connected to various coil parts. The first part may identify the second part via a circuit connected through a shipper.

[0037]

[0040] Referring now to Figure 4, another example of a coil array 44 is shown. As shown in Figure 4, the coil array 44 comprises a coil element portion 22, an electronics module 24, and a plurality of transmit optical fibers 31 connected to the electronics module located in a first portion 62 of the coil array 44. A second portion 64 of the coil array 64 comprises a plurality of preamplifiers PRE (in communication with the plurality of transmit optical fibers 31), an analog-to-digital converter ADC, and a single optical fiber 32 connected to the analog-to-digital converter ADC. A zipper 34 (such as that described with reference to Figure 2) connects the first portion 62 and the second portion 64 to form an optical coupling between the first portion and the second portion.

[0038]

[0041] The present disclosure has been described with reference to the preferred embodiment. Modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiments be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims and their equivalents.

Claims

1. An MR coil sheet comprising a conductive magnetic resonance (MR) coil element or an MR coil element portion disposed on an electrical insulating sheet, wherein the MR coil sheet has an edge having a connection mechanism for connecting the MR coil sheets to construct an MR coil array, the connection mechanism comprising engagement teeth for connecting the MR coil sheets by interlocking to define a zipper for connecting the MR coil sheets, the engagement teeth including non-conductive engagement teeth and conductive engagement teeth, and the MR coil sheet including conductive MR coil element portions that are galvanically connected to each other by the conductive engagement teeth, an MR coil construction system.

2. The MR coil construction system according to claim 1, wherein the non-conductive engagement teeth are made of plastic and the conductive engagement teeth are made of a gold-plated copper alloy.

3. The MR coil construction system according to claim 1, wherein the connection mechanism comprises a continuous edge connector for connecting the MR coil sheets by interlocking to define a toothless zipper.

4. The MR coil construction system according to claim 1, wherein the electrical insulating sheet includes a lightweight foam housed in a plastic jacket.

5. One or more sensors for measuring patient characteristics of a patient, and at least one electronic processor programmed to output a recommended configuration of the MR coil array based on the measured patient characteristics The MR coil construction system according to claim 1, further comprising.

6. The one or more sensors include a camera for acquiring an image of the patient during transfer of the patient into the bore of an MR imaging device, The MR coil construction system according to claim 5, wherein the at least one electronic processor is programmed to estimate the recommended configuration of the MR coil array for the patient.

7. The engagement teeth of the MR coil sheet are optically inactive engagement teeth, and optical coupler engagement teeth, and The MR coil construction system according to claim 1, comprising at least one optical fiber connection portion including an optical coupling formed by interlocking optical coupler engagement teeth of at least one zipper of the MR coil array.

8. The MR coil construction system according to claim 1, further comprising a coil edge attachment including an edge of the MR coil sheet at a peripheral portion of the MR coil array where the duty teeth are not interlocked with the duty teeth of any other MR coil sheet.

9. The MR coil construction system according to claim 1, wherein two zippers of each of the MR coil arrays are either perpendicular to each other or parallel to each other.

10. The MR coil construction system according to claim 1, wherein the MR coil sheet further comprises a preamplifier electrically connected to the conductive MR coil element or the MR coil element portion.

11. An MR coil array constructed using the MR coil array construction system according to any one of claims 1 to 10.

12. The MR coil array according to claim 11, wherein the connection mechanism extends parallel to each other in a transverse direction of the MR coil array.

13. The MR coil array according to claim 11, wherein the connection mechanism forms an array of connection mechanisms dispersed over the entire surface of the MR coil array.

14. A method of constructing a magnetic resonance (MR) coil array, the method comprising: connecting MR coil sheets including conductive MR coil elements or MR coil element portions to each other using edge connectors to construct the MR coil array.

15. The method further comprising: acquiring an image of a patient being transferred into a bore of a medical imaging device; determining one or more characteristics of the patient from the acquired image; outputting a proposed configuration of the MR coil array including a grid of MR coil sheets; and assembling the MR coil array according to the proposed configuration. The method according to claim 14.

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