MAGNETIC RESONANCE ANTENNA WITH WIRE STRUCTURE EMBEDDED IN FOAM

Abstract

Systems for a magnetic resonance antenna, an MR local coil, a magnetic resonance device, and a method of producing a magnetic resonance antenna. The magnetic resonance antenna includes at least one wire structure. The at least one wire structure is shaped such that an electrical voltage may be induced in the at least one wire structure by a magnetic resonance signal. The magnetic resonance antenna also includes at least one accommodating body in which the at least one wire structure is embedded, for example completely.

Claims

1. A magnetic resonance antenna comprising: at least one wire structure shaped such that an electrical voltage may be induced in the at least one wire structure by a magnetic resonance signal; and at least one accommodating body in which the at least one wire structure is embedded completely.

2. The magnetic resonance antenna as claimed in claim 1, wherein the at least one accommodating body consists of at least one of a foam material, a felt material, or a knitted fabric.

3. The magnetic resonance antenna of claim 1, wherein the at least one wire structure comprises at least one of a single electrical line, a coaxial electrical line, a triaxial electrical line, or a sheathed multiple electrical line.

4. The magnetic resonance antenna of claim 1, wherein the at least one wire structure comprises at least one capacitor.

5. The magnetic resonance antenna of claim 1, wherein the magnetic resonance antenna comprises at least one component that is fixedly connected to the at least one accommodating body, for connecting an electronic component.

6. The magnetic resonance antenna of claim 1, wherein the at least one accommodating body is planar and includes two opposing surfaces, wherein the at least one wire structure is disposed centrally between the two opposing surfaces.

7. The magnetic resonance antenna of claim 1, wherein the at least one accommodating body includes regions close to the at least one wire structure that have a lower density than regions remote from the at least one wire structure.

8. The magnetic resonance antenna of claim 7, wherein the regions of the at least one accommodating body remote from the at least one wire structure include at least one aperture.

9. A local coil comprising: at least one magnetic resonance antenna comprising: at least one wire structure shaped such that an electrical voltage may be induced in the at least one wire structure by a magnetic resonance signal; and at least one accommodating body in which the at least one wire structure is embedded completely.

10. The local coil of claim 9, further comprising: an outer skin, wherein the at least one accommodating body including the at least one wire structure embedded therein is enclosed by the outer skin.

11. The local coil of claim 9, wherein the at least one wire structure is flexible, the at least one accommodating body is flexible, or the at least one wire structure and the at least one accommodating body is flexible.

12. The local coil of claim 9, wherein the at least one wire structure comprises a shortening capacitor.

13. A method for producing a magnetic resonance antenna, the method comprising: providing a sheet of foam material; making at least one slit in the sheet; placing at least one wire structure in the at least one slit; and applying pressure, temperature, or pressure and temperature to the sheet so that the at least one slit is sealed.

14. The method of claim 13, wherein the sheet provided includes a thickness of between 5 and 15 mm

15. The method of claim 13, wherein the at least one slit is made on a surface of the sheet; and wherein, after placing, a liner of foam material, is applied to the surface.

16. The method of claim 15, wherein the liner includes a thickness of between 1 and 3 mm.

17. The method of claim 15, further comprising: bonding the liner and the sheet to form a homogeneous material composite.

18. The method of claim 13, wherein the slit is made using a blade, a punch, a laser, or a milling machine.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0052] FIG. 1 depicts a magnetic resonance device with a local coil.

[0053] FIGS. 2, 3, and 4 depict various representations of possible magnetic resonance antennas according to embodiments.

[0054] FIG. 5 depicts cross-sectional representations of possible wire structures of a magnetic resonance antenna according to an embodiment.

[0055] FIG. 6 depicts a possible structure of a local coil with a magnetic resonance antenna according to an embodiment.

[0056] FIG. 7 depicts a flowchart of a method for producing a magnetic resonance antenna according to an embodiment.

[0057] FIG. 8 depicts different stages in the production of a magnetic resonance antenna according to an embodiment.

DETAILED DESCRIPTION

[0058] FIG. 1 schematically illustrates a magnetic resonance device 10. The magnetic resonance device 10 includes a magnet unit 11 including a main magnet 12 for generating a powerful and, for example, time-constant main magnetic field 13. In addition, the magnetic resonance device 10 includes a patient receiving region 14 for accommodating a patient 15. The patient receiving region 14 in this embodiment is cylindrical in shape and is cylindrically enclosed in a circumferential direction by the magnet unit 11. However, any configuration of the patient receiving region 14 differing therefrom is possible. The patient 15 may be slid into the patient receiving region 14 by a patient positioning device 16 of the magnetic resonance device 10. The patient positioning device 16 includes a patient table 17 that is configured to be movable within the patient receiving region 14.

[0059] The magnet unit 11 also includes a gradient coil unit 18 for generating magnetic field gradients that are used for spatial encoding during imaging. The gradient coil unit 18 is controlled by a gradient control unit 19 of the magnetic resonance device 10. The magnet unit 11 additionally includes a radiofrequency antenna unit 20 that in this embodiment is implemented as a body coil fixedly incorporated in the magnetic resonance device 10. The radiofrequency antenna unit 20 is controlled by a radiofrequency antenna control unit 21 of the magnetic resonance device 10, and radiates radiofrequency magnetic resonance sequences into an examination space that may be constituted by a patient receiving region 14 of the magnetic resonance device 10. This causes excitation of atomic nuclei to be imparted to the main magnetic field 13 generated by the main magnet 12. Relaxation of the excited atomic nuclei causes magnetic resonance signals to be generated. The radiofrequency antenna unit 20 is configured to receive the magnetic resonance signals.

[0060] The magnetic resonance device 10 includes a system control unit 22 for controlling the main magnet 12, gradient control unit 19, and for controlling the radiofrequency antenna control unit 21. The system control unit 22 centrally controls the magnetic resonance device 10, e.g., executing a predetermined imaging gradient echo sequence. The system control unit 22 additionally includes an evaluation unit (not shown in more detail) for evaluating the magnetic resonance signals acquired during the magnetic resonance examination. The magnetic resonance device 10 also includes a user interface 23 connected to the system control unit 22. Control information, such as imaging parameters, as well as reconstructed magnetic resonance images may be displayed for medical personnel on a display unit 24, e.g., on at least one monitor, of the user interface 23. In addition, the user interface 23 includes an input unit 25 by which information and/or parameters may be entered by medical personnel during a scanning process.

[0061] The magnetic resonance device 10 further includes a local coil 200 disposed directly on the patient 15. The local coil 200 incorporates a magnetic resonance antenna for use in conjunction with the magnetic resonance device 10, as shown by way of example in the following figures. The magnetic resonance antenna may be configured to receive magnetic resonance signals and/or transmit radiofrequency signals.

[0062] FIG. 2 depicts a magnetic resonance antenna 100 including a plurality of wire structures 101 shaped such that an electrical voltage may be induced in each of them by a magnetic resonance signal. The wire structures 101 are completely embedded in an accommodating body 102 made of a foam material. The wire structures 101 include a diameter D.sub.D. The accommodating body 102 keeps the wire structures in their shape and/or serves to provide a defined safe distance from the patient 15.

[0063] The wire structure 101 shown on the upper left includes a shortening capacitor 103 that is disposed on a circuit board 104. However, no circuit board may be used, but that the wire structure 101 is merely broken and the break point is electrically and mechanically protected by a heat shrink tube.

[0064] In addition, an electronic component 105 is disposed on the magnetic resonance antenna 100. This may be connected, for example, via a unit that is fixedly connected to the accommodating body 102.

[0065] The accommodating body 102 extends planarly in an x-y plane if the magnetic resonance antenna 100 is laid out flat. The accommodating body 102 includes two opposing surfaces, with the wire structures 101 disposed centrally between the opposing surfaces.

[0066] In the immediate vicinity of the wire structure, the magnetic resonance antenna is made thicker than in regions 107 remote from the wire structures 101 along the x-y plane, i.e., regions of the accommodating body 102 farther away from the wire structures 101. In the regions 107, the magnetic resonance antenna 100, for example the accommodating body 102, is made comparatively thin. The regions 107 may therefore also be referred to as membrane regions, since the regions 107 include a large planar extent, in this case in the x-y plane, in relation to their thickness.

[0067] The regions of the accommodating body 102 around the wire structures 101 may have a lower density than the regions 107 remote from the wire structures. For example, the regions 107 may be made of a more compressed foam material than the regions around the wire structures 101. The regions 107 are used to maintain the shape of the magnetic resonance antenna 100.

[0068] As may also be seen in FIG. 3, the regions of the accommodating body remote from the wire structures include a plurality of apertures 108, for example cutouts and/or holes. The smaller apertures 108 may be useful for fixing the magnetic resonance antenna 100 to other parts, for example other layers, of the local coil 200, for example using snap fasteners or Velcro areas, etc.

[0069] In addition, smaller apertures 108 are useful for routing cables within the local coil 200; cables may be threaded through the small apertures from one side of the accommodating body 102 to the other side of the accommodating body 102 such that such a cable may be disposed partially on one side and partially on the other side of the accommodating body 102.

[0070] In addition, the apertures 108 are configured to increase the flexibility of the magnetic resonance antenna 100. The larger apertures 108 may be suitable for providing openings to an outer skin of the local coil 200.

[0071] The magnetic resonance antenna also includes an antenna terminal 109 for connecting the magnetic resonance antenna 100 to an interface, for example a signal transmission cable, of the local coil 200.

[0072] The wire structures 101 fixed in the accommodating body 102 may be formed into a wide variety of shapes. FIG. 4 depicts possible shapes and the associated overlap regions 110, 111, 112 of the wire structures 101a, 101b, 101c, 101d. For example, the overlap region 110 of the wire structures 101a and 101b, the overlap region 112 of the wire structures 101c, 101b and 101d, and the overlap region 111 of the wire structures 101a, 101b, 101c and 101d are shown.

[0073] FIG. 5 depicts cross-sections of various types of electrical lines that may be used in the wire structures 101. The line type 121 is a single electrical conductor made of an electrically conductive material 121a surrounded by an insulating material 121b as a cable sheath. The line type 122 is a coaxial electrical line, i.e., a line including two coaxially arranged conductive materials 122da, 122b between which a dielectric 122c is disposed, and another insulating material 122d as a cable sheath. The line type 123 is a triaxial electrical line including three coaxially arranged conductive materials 123a, 123b, 123e, between each of which a dielectric 123c, 123d is disposed, and a further insulating material 123f as a cable sheath. The conductor type 124 is a sheathed multiple electrical line including two electrically conductive materials 123a, 123b disposed side by side, each sheathed by an insulating material 123c, 123d so as to be electrically insulated from one another; these are in turn surrounded by another electrically conductive material 123e and another insulating material 124f as a cable sheath.

[0074] By using such types of lines in the wire structures 101, very good values may be achieved for the magnetic resonance antenna 100 in terms of dielectric strength and mechanical resilience. They are available by the meter and do not require photochemical processing, but may be embedded in a foam in which, for example, a slit having the desired shape of the wire structure 101 has previously been made.

[0075] FIG. 6 depicts a typical structure of a local coil 200. It includes a magnetic resonance antenna 100 including an accommodating body 102 made of foam material and a wire structure 101 embedded therein. Here it also includes an electronic component 105 such as e.g., a preamplifier for amplifying the magnetic resonance signals received by the wire structure 101. For example, the electronic component 105 may include a rigid housing.

[0076] The local coil 200 also includes internal wiring 171 that may be threaded through the accommodating body 102, for example through apertures 108 in the accommodating body 102 at some locations. In this example, the internal wiring establishes a connection to a sheath current choke 170. The local coil 200 also includes a spacer layer 160 that provides height leveling of the electronic component 105. Other components 180 of the local coil 102 may be embedded in the accommodating body 102.

[0077] The hitherto described internal parts of the local coil 200 shown in FIG. 6 are enclosed from inside to out by three layers: a sliding layer 130, a padding layer 140, and an outer skin 150. The internal parts are not fixedly connected to the sliding layer 130 so that they may slide within it.

[0078] FIG. 7 schematically depicts a method for producing a magnetic resonance antenna, including the steps S1 to S4. In S1, a sheet of foam material is provided. FIG. 8 depicts such a provided sheet 113 that may for example have a thickness t2 of between 5 and 15 mm

[0079] In S2, at least one slit is made in the sheet. The at least one slit may be made, for example, using a scalpel, a punching knife, and/or a laser. Such a slit 112 is shown in FIG. 8. The slit 112 is made on a surface 115 of the sheet 113.

[0080] In S3, at least one wire structure 101 is placed in the at least one slit. After placement, the at least one wire structure is held in place by the foam material surrounding it. Such a placed wire structure 101 is shown in FIG. 8. The position of the wire structure 101 may be adjusted depending on the slit depth d. A liner 114 of foam material may be applied to the surface 115, as shown in the middle section of FIG. 8. For example, the liner 114 may include a thickness t1 of between 1 and 8 mm, for example between 2 and 5 mm

[0081] For example, the sheet 113 may have a thickness t2 of 8 mm, the liner may have a thickness t1 of 2 mm, and the slit may have a depth d of 4 mm. Taking into account the thickness of the wire structure of e.g., 2 mm, the wire structure may be located centrally between the upper surface of the liner 114 and the lower surface of the sheet 113.

[0082] In S4, pressure and/or temperature is applied to the sheet so that the at least one slit is sealed. The thermostamping step results in the structure shown in the lower section of FIG. 8. The liner 114 and sheet 113 have combined to form an ideally homogeneous accommodating body 102. The wire structure is centered between opposing surfaces 116a and 116b of the accommodating body 102.

[0083] The accommodating body 102 has different thicknesses depending on the distance from the wire structure 101: in an area 116 around the wire structure 101 with a diameter D.sub.S, the accommodating body 102 is thicker than in the areas 107 farther away from the wire structure 101. In step S4, the areas 107 have been more heavily compressed so that they also have a higher density.

[0084] For example, after the thermostamping step, the maximum thickness of the magnetic resonance antenna 110 in the area 116 is compressed from 10 to 8 mm and holds the wire structure 101 in the center. In the areas 107, the magnetic resonance antenna 100 is compressed from an initial thickness of 10 mm to a thickness of 1 to 4 mm, for example.

[0085] The previously applied liner 114 may reduce the risk of the slit 112 gaping open and exposing the wire structure 101 after applying pressure and/or temperature.

[0086] As may be seen in FIG. 2, this production method may also be used to create overlapping wire structures that cross at intersection points 117. Shortening capacitors 103, for example, previously incorporated into the wire structure 101 may also be encased in the foam. For any electronic components 105, a framework or an underside of an electronics housing for example may be co-impressed in the foam to create a tight bond between wire structures 101 receiving magnetic resonance signals and the electronics.

[0087] The methods described in detail above, as well as the magnetic resonance antenna, local coil and magnetic resonance device illustrated, are merely embodiments that may be modified in a variety of ways by persons skilled in the art without departing from the scope of the invention. Moreover, the use of the indefinite articles “a” or “an” does not preclude the features in question from being present more than once. Similarly, the term “unit” does not preclude the components in question from including a plurality of interacting sub-components that may also be spatially distributed.

[0088] It is to be understood that the elements and features recited in the appended claims may be combined in different ways to produce new claims that likewise fall within the scope of the present invention. Thus, whereas the dependent claims appended below depend from only a single independent or dependent claim, it is to be understood that the dependent claims may, alternatively, be made to depend in the alternative from any preceding or following claim, whether independent or dependent, and that such new combinations are to be understood as forming a part of the present specification.

[0089] While the present invention has been described above by reference to various embodiments, it may be understood that many changes and modifications may be made to the described embodiments. It is therefore intended that the foregoing description be regarded as illustrative rather than limiting, and that it be understood that all equivalents and/or combinations of embodiments are intended to be included in this description.