Magnetic resonance coil device with flexible array having multiple magnetic resonance receive coils - Patents.com
Patent Information
- Application Number
- JP2023567097
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2021-05-14
- Filing Date
- 2022-05-07
- Publication Date
- 2025-04-25
AI Technical Summary
Conventional RF receive coils in MRI systems are bulky and rigid, limiting their ability to efficiently couple with the desired anatomy and causing discomfort during imaging due to fixed positioning, necessitating multiple coils for different body parts.
A magnetic resonance coil device with an array of overlapping receiver coils sandwiched between flexible outer layers and spacers, allowing for flexible positioning and adaptation to various body shapes by sliding and overlapping, with spacers ensuring coil overlap and flexibility.
Enables flexible and comfortable MRI imaging by allowing the coil array to conform to different body contours, enhancing signal reception and reducing the need for multiple specialized coils.
Smart Images
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Abstract
Description
[Technical field]
[0001] The present invention relates to the field of magnetic resonance imaging (MRI) systems, and in particular to a magnetic resonance coil arrangement for a magnetic resonance system comprising an array having a plurality of magnetic resonance receive coils configured to receive magnetic resonance radio frequency signals. [Background technology]
[0002] Magnetic resonance CT is an imaging technique based on the principle of nuclear magnetic resonance, i.e., atomic nuclei with non-zero spin have a magnetic moment. In medical MRI, the atomic nuclei with non-zero spin are usually the nuclei of hydrogen atoms present in the human or animal body. Radio frequency (RF) waves forming a B1 excitation field are directed at the atomic nuclei in an external magnetic field, resulting in the excitation of protons and their subsequent relaxation process. The relaxation of the protons results in the emission by the atomic nuclei of RE signals, which can be detected and processed to form an image.
[0003] A typical MRI system generally comprises a magnet, e.g., a superconducting electromagnet, which generates a strong static magnetic field, gradient coils which generate linear variations in the static magnetic field, an RF transmit coil which generates a B1 excitation field, and an RF receive coil which detects the magnetic resonance RE signals emitted by relaxed atomic nuclei.
[0004] Typically, multiple RF receive coils are used in MRI systems forming a receive coil array. These RF receive coils, also called "surface coils", typically comprise several receive loops arranged in an array. The typical spatial orientation of these arrays is Cartesian or hexagonal. Conventional RF receive coils and RF receive coil arrays tend to be bulky and / or rigid and are configured to be maintained in a fixed position relative to other RF receive coils in the coil array and relative to the imaging subject, respectively. The bulkiness and lack of flexibility tend to prevent the RF receive coil from most efficiently coupling with the desired anatomical structure of the imaging subject, making the imaging process uncomfortable for the imaging subject. Thus, there are many different coils for many different imaging situations, i.e. foot coils, ankle coils, knee coils, shoulder coils, etc. for individual body parts, or heart coils or anterior coils for the torso.
[0005] US 2008 / 238424 A1 discloses a flexible RF coil array based on PCB-based coil loops joined by flexible hinges. According to this document, the radio frequency coil array includes a plurality of conductive RF loops configured to excite or receive magnetic resonance signals and a plurality of electronic modules corresponding to the plurality of conductive RF loops. The electronic modules are grouped into a compact electronic area. Each RF coil is operatively connected to a corresponding electronic module. Each electronic module includes at least a preamplifier. Summary of the Invention [Problem to be solved by the invention]
[0006] It is an object of the present invention to provide a versatile magnetic resonance coil arrangement for a magnetic resonance system having an array of multiple magnetic resonance receive coils, which can be easily adapted to the shapes of different parts of the human body. [Means for solving the problem]
[0007] According to the invention, this object is addressed by the subject matter of claim 1. Preferred embodiments of the invention are set forth in the dependent claims.
[0008] Thus, according to the present invention, there is provided a magnetic resonance coil device comprising an array having a plurality of magnetic resonance receive coils configured to receive magnetic resonance radio frequency signals, and two external layers, the magnetic resonance receive coils being arranged between the external layers such that at least some of the magnetic resonance receive coils partially overlap with at least one other adjacent magnetic resonance receive coil, respective overlap regions between two respective adjacent magnetic resonance receive coils being formed, at least one spacer being arranged in at least some of these overlap regions, and at least one of the external layers being flexible.
[0009] In this way, the magnetic resonance receiver coils sandwiched by the two outer layers can slide between the outer layers and move loosely. Their respective positions relative to each other and their overlap with one or more adjacent magnetic resonance receiver coils can be ensured by spacers. This allows the magnetic resonance coil arrangement to bend in two directions while its components remain in position, and the overlap of the respective magnetic resonance receiver coils relative to each other is maintained. In this way, bending around a cylinder or torso, i.e. bending in one direction, but also bending around structures that are convex in two dimensions, such as the head, shoulders or knees, is possible. According to a preferred embodiment of the invention, not only some of the magnetic resonance receiver coils but all of the magnetic resonance receiver coils each partially overlap with at least one other adjacent magnetic resonance receiver coil, so that a respective overlap region between two respective adjacent magnetic resonance receiver coils is formed, and in these overlap regions at least one spacer is respectively arranged.
[0010] In general, the surface of the spacer may be designed in a different way, according to a preferred embodiment of the invention, with at least some of the spacers, the surface of the spacer facing the inside of the outer layer being a flat surface. Preferably, for all of the spacers, the surface of the spacer facing the inside of the outer layer is a flat surface. Also, in a plan view of the spacer, the shape of the spacer is preferably almond-shaped and the shape of each magnetic resonance receiving coil is preferably circular. Here, the term "almond-shaped" is understood to be a shape achieved by two curved lines, preferably segments of a circle, attached to each other at the ends of these curves. This may form an oval or hair follicle shape. Other combinations of shapes for the spacer and the coils are possible, such as square, hexagonal or octagonal.
[0011] Furthermore, according to a preferred embodiment of the invention, at least some of the spacers have a rectangular shape in a cross section perpendicular to the plane. Preferably, all of the spacers have a rectangular shape in a cross section perpendicular to the plane. According to another preferred embodiment of the invention, at least some of the spacers have a rectangular shape in a cross section perpendicular to the flat surface with grooves on the transverse surfaces connecting the flat surfaces facing the inside of the outer layer to each other. Preferably, this applies to all of the spacers. In this way, the loops of the respective magnetic resonance receiving coils can slide into these grooves and therefore they can be easily held in their intended place.
[0012] According to a further preferred embodiment of the invention, at least some of the spacers are fixedly attached to the inside of the outer layer. Preferably, this applies to all of the spacers. The spacers can be fixed to the inside of the outer layer in different ways. Preferably, the spacers are glued to the inside of the outer layer.
[0013] In general, the present invention allows for magnetic resonance receiving coils to be fixed in a sandwich structure between the outer layers, while at least some of the magnetic resonance receiving coils partially overlap at least one other adjacent magnetic resonance receiving coil and are provided with a spacer in the respective overlapping region, but are not fixed to another spacer and are not fixed to any of the outer layers. Thus, according to a preferred embodiment of the present invention, the loops of the magnetic resonance receiving coils are arranged very loosely between the outer layers, for example in an air gap in the coil array. The movement of the loops is only limited by the spacer between the inner sides of the outer layers. This provides a high flexibility of the magnetic resonance coil arrangement. In this respect, preferably all of the magnetic resonance receiving coils partially overlap at least one other adjacent magnetic resonance receiving coil and are provided with a spacer in the respective overlapping region are not fixed to another spacer and are not fixed to any of the outer layers.
[0014] Generally, different types of materials can be used for the spacers. According to a preferred embodiment of the invention, at least a part of the spacer is at least partially made from a flexible material. Preferably, at least a part of the spacer is at least partially made from a flexible foam. More preferably, all of the spacer is made from a flexible foam.
[0015] According to a preferred embodiment of the invention, at least some of the spacers comprise two parts that are separate from each other or connected to each other by a hinge, preferably a film hinge. This provides additional flexibility. Preferably, all of the spacers comprise two parts that are separate from each other or connected to each other by a hinge.
[0016] Furthermore, according to a preferred embodiment of the present invention, at least some of the spacers comprise a rigid section in which at least one electrical device is arranged. In this respect, according to a preferred embodiment of the present invention, the electrical device is a low noise amplifier (LNA) for amplifying the magnetic resonance radio frequency signals received by the magnetic resonance receiving coil. Preferably, the LNA is connected to the feed point of the magnetic resonance coil device by a micro-coaxial cable.
[0017] According to a preferred embodiment of the invention, the flexible outer layer is reversibly deformable with respect to the convex surface. In this way, bending in two directions is possible, since no area-preserving material is used in the outer layer. In this respect, preferably, the flexible outer layer is made of a textile sheet. Such a textile sheet can be made of different types of fabric, for example woven or nonwoven fleece. According to a preferred embodiment of the invention, the flexible outer layer does not show flexibility along its extension direction. According to a preferred embodiment of the invention, in the case of an outer layer made of a fabric material, this means that no stretching material is used. According to the present invention, the outer layer may be completely closed, but according to a preferred embodiment of the invention, at least one of the outer layers, preferably both, comprises air holes. This allows air circulation and thus specific cooling of the body part of the patient to which the magnetic resonance coil device is applied. Preferably at least some, more preferably all, of the magnetic resonance receiving coils are arranged in a Cartesian or hexagonal spatial orientation relative to each other.
[0018] As mentioned above, the flexibility of the array is achieved by the fact that at least some of the magnetic resonance receiving coils are arranged in the gap between the spacer and at least one of the flexible outer layers. In this respect, it is preferable that both outer layers are flexible. Moreover, in this way, the magnetic resonance receiving coils can move to provide flexibility, but they are held in their intended place by the spacer. The highest flexibility is achieved when all the magnetic resonance receiving coils are arranged between the two outer layers in this way, but it may be sufficient to have only the magnetic resonance receiving coils or some of the magnetic resonance receiving coils in a certain area of the array arranged in this way. Therefore, a person skilled in the art can determine on the basis of his expertise how the magnetic resonance receiving coils should be arranged in this way to achieve the desired flexibility for different applications.
[0019] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter, but such embodiments do not necessarily represent the full scope of the invention, and therefore reference should be made to the claims and this specification for interpreting the scope of the invention. [Brief description of the drawings]
[0020] [Figure 1A] 1 illustrates a schematic of an array having multiple magnetic resonance receive coils in a Cartesian orientation relative to one another. [Figure 1B] 1 illustrates a schematic of an array having multiple magnetic resonance receive coils oriented in a hexagonal fashion relative to one another. [Diagram 2] 1 illustrates diagrammatically two adjacent magnetic resonance receive coils overlapping each other according to a preferred embodiment of the present invention; [Diagram 3] 1 shows a schematic cross-sectional view of a portion of an array having multiple magnetic resonance receive coils according to a preferred embodiment of the present invention. [Figure 4] 1 shows a schematic cross-sectional view of a portion of an array having multiple magnetic resonance receive coils according to another preferred embodiment of the present invention; [Diagram 5] 1 shows a schematic perspective view of a spacer with rigid sections for an electrical device according to a preferred embodiment of the present invention; [Figure 6] 1 shows diagrammatically two adjacent magnetic resonance receive coils overlapping each other and comprising a rigid section for an electrical device according to a preferred embodiment of the present invention. [Figure 7A] 13 shows a schematic representation of a spacer with a rigid section for an electrical device before insertion of the electrical device according to another preferred embodiment of the present invention; [Figure 7B] 13 shows a schematic representation of a spacer with a rigid section for an electrical device after the electrical device has been inserted according to another preferred embodiment of the present invention; [Figure 7C] 3 shows a schematic representation of a spacer with a rigid compartment for an electrical device after closing the compartment with a cover according to another preferred embodiment of the invention; [Figure 8] 13A illustrates, in accordance with another preferred embodiment of the present invention, a schematic representation of an array having multiple magnetic resonance receive coils disposed on a lower outer layer prior to attachment of an upper outer layer; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] The present invention allows different relative arrangements of magnetic resonance receive coils 400 configured to receive magnetic resonance radio frequency signals. In this regard, FIG. 1A shows a schematic diagram of an array 100 having a plurality of magnetic resonance receive coils 400 in a Cartesian orientation relative to one another, and FIG. 1B shows a schematic diagram of an array 100 having a plurality of magnetic resonance receive coils 400 in a hexagonal orientation relative to one another. For clarity, the figures show. In FIG. 1A and FIG. 1B, not all magnetic resonance receive coils 400 are indicated by reference numbers. In both cases, all magnetic resonance receive coils 400, except for the outermost magnetic resonance receive coil 400, overlap with four adjacent magnetic resonance receive coils 400.
[0022] From Fig. 2, two adjacent magnetic resonance receive coils 400 overlapping each other are shown in more detail. Preferably, all overlapping regions of the array 100 according to the present embodiment are designed in this way. For clarity, all other adjacent magnetic resonance receive coils 400 are omitted in Fig. 2. Looking at Fig. 2, the overlapping region between the two magnetic resonance receive coils 400 has an almond shape. In this overlapping region, a spacer 300 is arranged, which also has an almond shape.
[0023] Figure 3 is a cross-sectional view perpendicular to the view of the magnetic resonance receive coil 400 of figure 2. Here it can be seen that the magnetic resonance receive coil 400 and the spacer 300 are sandwiched between two flexible outer layers 200, 201 made of a fabric material. The surface 250 of the spacer 300 facing the inside of the outer layers 200, 201 is a flat surface, and in a cross-sectional view perpendicular to the flat surface 250, the spacer 300 has a rectangular shape, which means that the surface 315 of the spacer 300 perpendicular to the surface 250 of the spacer 300 facing the inside of the outer layers 200, 201 is a flat surface. In this way, the two magnetic resonance receive coils 400 are held in place relative to each other by the spacer 300.
[0024] According to an alternative embodiment of the invention shown in Fig. 4, the spacer 300 has a rectangular shape, in a cross section perpendicular to the planes 250, with grooves 320 in the lateral surfaces 315 connecting the inner facing planes 250 of the outer layers 200, 201 to each other. In this way, the loops of the respective magnetic resonance receive coils 400 can slide into these grooves 320 between the outer regions 310 of the spacer 300 and therefore they can be easily held in their intended place.
[0025] Although the schematics of figures 3 and 4 show some space between the spacers 300 and the external layers 200, 201, according to a preferred embodiment of the invention described herein, all spacers 300 of the array are fixedly attached to the inside of the external layers 200, 201 by adhesive. In this way, air gaps 210 are formed between the two flexible layers 200, 201, in which the magnetic resonance receiving coils 400 can be placed. Also, the magnetic resonance receiving coils 400 placed in these air gaps 210 are not fixed to the other spacers 300, and are not fixed to any of the external layers 200, 201. This provides the possibility of free movement of the magnetic resonance receiving coils 400 in the sandwich structure between the two flexible external layers 200, 201, while the magnetic resonance receiving coils 400 are held in their respective positions. In this way, a very flexible array 100 is achieved without the risk of parts of the magnetic resonance receiving coils 400 moving away from their intended respective positions.
[0026] This flexibility is further enhanced because the spacers 300 themselves are formed from a flexible material, preferably foam, and at least some of the spacers 300 of the array 100 include two parts 311, 312 that are separate from one another. This is shown diagrammatically in FIG. 8, which also shows that the outer layers 200, 201 include aeration holes 220. FIG. 8 also shows the option for the two parts 311, 312 of the spacer 300 to be connected to one another by a film hinge 313. For clarity, even in FIG. 8, not all components of the array 100 are identified by reference numbers.
[0027] FIG. 5 shows a schematic perspective view of a spacer with a rigid section 500 according to a preferred embodiment of the invention. In this rigid section 500, an electrical device 510 is arranged. This rigid section 500 may be closed at its upper side and its lower side with respective covers 330, 340. According to a preferred embodiment of the invention described herein, the electrical device 510 is a low noise amplifier (LNA) for amplifying the magnetic resonance radio frequency signals received by the magnetic resonance receiving coil 400. According to this embodiment, the electrical device 510 is connected to the power supply point of the array 100 by a micro-coaxial cable (not shown). As shown in FIGS. 5 and 6, the rigid section 500 comprises two subchambers, in each of which an electrical device 510 is arranged. These electronic devices 510 are LNAs for two adjacent magnetic resonance receiving coils 400, which means that in the array 100, the two adjacent magnetic resonance receiving coils 400 share such a spacer 300 with the rigid section 500 for its two LNAs.
[0028] As shown in more detail and diagrammatically in Fig. 7A, the spacer 300 with a rigid section 500 for an electrical device 510 is composed of the rigid section 500 itself and two spacer parts 311, 312 made of flexible foam and connected to two opposite sides of the rigid section, preferably by gluing. Then, as shown diagrammatically in Fig. 7B, the electrical device 510 is placed inside the rigid section 500, and as shown in Fig. 7C, the rigid section 500 is closed with a cover 330.
[0029] While the present invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description are to be considered as illustrative or exemplary and not restrictive, and the present invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be interpreted as limiting the scope. Moreover, for the sake of clarity, not all elements in the drawings have been labeled with reference signs. [Explanation of symbols]
[0030] Array 100 Outer layer 200 Outer layer 201 void 210 Ventilation hole 220 Spacer flat surface 250 Spacer 300 Spacer outer region 310 Spacer first portion 311 Spacer second portion 312 Film hinge 313 Lateral surface 315 groove 320 Cover 330 Cover 340 Magnetic resonance receiving coil 400 Rigid Section 500 Electrical Equipment 510
Claims
1. 1. A magnetic resonance coil arrangement for a magnetic resonance system, comprising:
1. A magnetic resonance coil device comprising: an array having a plurality of magnetic resonance receive coils configured to receive magnetic resonance radio frequency signals; and two external layers, the magnetic resonance receive coils being arranged between the external layers in such a manner that at least some of the magnetic resonance receive coils partially overlap at least one other adjacent magnetic resonance receive coil such that respective overlapping regions between two respective adjacent magnetic resonance receive coils are formed, and at least one spacer is arranged within at least some of these overlapping regions, respectively, and at least some of the spacers are fixedly attached to an inside of the external layers such that the magnetic resonance receive coils are (i) very loosely positioned between the external layers in gaps between the spacers in the coil array, and (ii) held in a predetermined position relative to each other by the spacers, and at least one of the external layers is flexible.
2. The spacers are rigidly attached to the inside of the outer layer so as to form gaps between adjacent spacers; 2. The magnetic resonance coil device of claim 1, wherein the magnetic resonance receive coil (i) is disposed within the gap, between the outer layers, and held in place by a spacer between the gaps, and (ii) is not fixed to either another spacer or to the outer layers.
3. A magnetic resonance coil device as described in claim 1 or 2, wherein for at least some of the spacers, the surface of the spacer facing the inside of the outer layer is a flat surface.
4. A magnetic resonance coil device as described in claim 3, wherein in a cross-sectional view perpendicular to the flat surface, at least some of the spacers have a rectangular shape.
5. A magnetic resonance coil device as described in claim 3, wherein at least some of the spacers, in a cross-sectional view perpendicular to the flat surfaces, have a rectangular shape with grooves in their lateral surfaces connecting the flat surfaces facing the inside of the outer layer to each other.
6. A magnetic resonance coil device as described in any one of claims 1 to 5, wherein at least some of the magnetic resonance receiving coils that partially overlap with at least one other adjacent magnetic resonance receiving coil and have spacers in each overlapping region are not fixed in another space or to any of the external layers.
7. A magnetic resonance coil device as claimed in any one of claims 1 to 6, wherein at least some of the spacers are at least partially formed from a flexible material.
8. A magnetic resonance coil device as described in any one of claims 1 to 7, wherein at least some of the spacers are separated from each other or have two parts connected to each other by a hinge, preferably a film hinge.
9. A magnetic resonance coil device as claimed in any one of claims 1 to 8, wherein at least some of the spacers have a rigid section in which at least one electrical device is arranged.
10. A magnetic resonance coil device as described in claim 9, wherein the electrical device is an LNA for amplifying a magnetic resonance radio frequency signal received by the magnetic resonance receiving coil.
11. A magnetic resonance coil device as described in any one of claims 1 to 10, wherein the one or more flexible outer layers are reversibly deformable into a convex surface.
12. The magnetic resonance coil device of claim 11, wherein the flexible outer layer or layers are made from a textile sheet.
13. A magnetic resonance coil device as described in any one of claims 1 to 12, wherein the one or more flexible outer layers do not exhibit flexibility along their extension direction.
14. A magnetic resonance coil device as claimed in any one of claims 1 to 13, wherein at least one of the external layers has an air vent.
15. A magnetic resonance coil device as claimed in any one of claims 1 to 14, wherein both outer layers are flexible.