초록 ▼

The subject invention pertains to a technique and device that can isolate and separate resultant electromagnetic fields of volume coils at high frequency. In an embodiment, an RF shield can be used to isolate and separate resultant electromagnetic fields. In an embodiment, the shield can have a cyli

The subject invention pertains to a technique and device that can isolate and separate resultant electromagnetic fields of volume coils at high frequency. In an embodiment, an RF shield can be used to isolate and separate resultant electromagnetic fields. In an embodiment, the shield can have a cylindrical shape that can form a partially closed volume in which an object to be imaged, or sample, can be inserted. In an embodiment, the RF shield can be part of a RF coil. In a specific embodiment, some parts of a volume coil can be inside a shield, and the other parts of a volume coil can be outside the shield. The shielding of some of the parts of a volume coil can create conductor patterns corresponding to the specific parts inside the shield and the specific parts outside the shield. In an embodiment, two or more conductor patterns can be placed in proximity to the same shield and either be driven independently, driven together, or act as receiving elements, combined or uncombined. This embodiment is advantageous because the combination of conductor patterns can be optimized by the flexibility of separating the fields of end-rings from the fields of leg currents.

대표청구항 ▼

The invention claimed is: 1. A magnetic resonance imaging RF shielded coil array, comprising: a plurality of conducting members, wherein the plurality of conducting members are electrically connected and form an RF coil array; and an RF shield, wherein the RF shield forms a partially closed volume;

The invention claimed is: 1. A magnetic resonance imaging RF shielded coil array, comprising: a plurality of conducting members, wherein the plurality of conducting members are electrically connected and form an RF coil array; and an RF shield, wherein the RF shield forms a partially closed volume; wherein at least one of the plurality of conducting members is located outside of the partially closed volume such that RF field produced by the at least one of the plurality of conducting members is shielded from the inside of the partially closed volume, wherein at least one of the remaining plurality of conducting members is located inside of the partially closed volume. 2. The RF shielded coil array according to claim 1, wherein the RF shield forms a partially closed cylindrical volume. 3. The RF shielded coil array according to claim 1, wherein the plurality of conducting members comprise a plurality of subgroups of conducting members, wherein at least one of the plurality of subgroups of conducting members forms a resonant circuit. 4. The RF shielded coil array according to claim 1, wherein the RF coil array has associated with it at least one mode selected from the following group: a waveguide mode and a dielectric resonator mode. 5. The RF shielded coil array according to claim 1, wherein the RF coil array has associated with it a coil resonant mode. 6. The RF shielded coil array according to claim 5, further comprising a means for controlling the RF field within the partially closed volume, wherein the means for controlling the RF field controls the excitation phase and amplitude of the coil resonant mode, the wave guide mode and/or dielectric resonator mode. 7. The RF shielded coil array according to claim 4, further comprising a means for controlling the RF field within the partially closed volume, wherein the means for controlling the RF field controls the excitation phase and amplitude of the wave guide mode and/or dielectric resonator mode. 8. The RF shielded coil array according to claim 2, wherein the partially closed cylindrical volume is a partially closed circular cylindrical volume. 9. The RF shielded coil array according to claim 1, wherein at least two of the plurality of conducting members are electrically connected by a connecting conductor, wherein the connecting conductor passes through the RF shield. 10. The RF shielded coil array according to claim 1, wherein the RF shield comprises capacitors that reduce or prevent low frequency currents. 11. The RF shielded coil array according to claim 6, wherein the means for controlling the RF field within the partially closed volume comprises: a drive system for driving one or more of the plurality of conducting members, wherein the drive system drives the one or more of the plurality of conducting members from particular locations such that the means for controlling the RF field includes or excludes known modes. 12. The RF shielded coil array according to claim 1, wherein the RF shield comprises complete, partial, or a combination of complete and partial conducting layers. 13. The RF shielded coil array according to claim 1, further comprising: one or more additional RF shields, wherein each of the one or more additional shields comprise complete, partial, or a combination of complete and partial conducting layers. 14. The RF shielded coil array according to claim 13, wherein each of the one or more additional shields comprise complete, partial, or a combination of complete and partial conducting layers. 15. The RF shielded coil array according to claim 13, further comprising: additional plurality of conducting members, wherein the one or more additional shields and the additional plurality of conducting members adjusts the frequency or frequencies of a mode. 16. The RF shielded coil array according to claim 13, wherein the partially closed volume is a partially closed cylindrical volume, wherein the one or more additional shields are each located at a different radius about the partially closed cylindrical volume. 17. The RF shielded coil array according to claim 15, wherein one or more of the additional plurality of conducting members are located between the RF shield and one of the one or more additional RF shields. 18. The RF shielded coil array according to claim 17, wherein one or more of the remaining conducting members of the additional plurality of conducting members are located outside of the one or more of the additional shields. 19. The RF shielded coil array according to claim 6, wherein the means for controlling the RF field within the partially closed volume comprises: particular conductive patterns on the RF shield for allowing or preventing current associated with a mode on the RF shield. 20. The RF shielded coil array according to claim 1, wherein the RF coil array is a volume coil, wherein parts of the volume coil are located inside the partially closed volume and other parts of the volume coil are located outside the partially closed volume. 21. The RF shielded coil array according to claim 20, wherein the volume coil is a birdcage coil, wherein the birdcage coil comprises a plurality of leg conductors, a first end-ring, and a second end-ring. 22. The RF shielded coil array according to claim 21, wherein the plurality of leg conductors are located inside the partially closed volume and the first end-ring and second end-ring are located outside the partially closed volume. 23. The RF shielded coil array according to claim 21, wherein one or more of the plurality of leg conductors are located outside the partially closed volume and the first end-ring and second end-ring are located inside the partially closed volume. 24. The RF shielded coil array according to claim 21, wherein the plurality of leg conductors and the second end-ring are located inside the partially closed volume and the first end-ring is located outside the partially closed volume. 25. The RF shielded coil array according to claim 21, wherein one or more of the plurality of leg conductors and the second end-ring are located outside the partially closed volume and the first end-ring is located inside the partially closed volume. 26. The RF shielded coil array according to claim 1, further comprising a second plurality of conducting members, wherein the second plurality of conducting members are electrically connected and form a second RF coil array, wherein at least one of the second plurality of conducting members is located outside of the partially closed volume and at least one of the remaining second plurality of conducting members is located inside of the partially closed volume. 27. The RF shielded coil array according to claim 20, wherein the RF coil array and the second RF coil array are driven independently, driven together, or act as combined or uncombined receiving elements. 28. The RF shielded coil array according to claim 27, further comprising a means for precision tuning and isolation adjustments for the two or more conductor patterns. 29. The RF shielded coil array according to claim 27, wherein the means for precision tuning and isolation adjustments comprises capacitors. 30. The RF shielded coil array according to claim 1, wherein the RF shield allows gradient fields to pass through. 31. The RF shielded coil array according to claim 1, wherein the RF shield comprises a plurality of shielding structures. 32. The RF shielded coil array according to claim 1, wherein the RF shield comprises a conducting layer. 33. The RF shielded coil array according to claim 1, wherein the RF shield is non-resonant and low impedance. 34. A method for detecting magnetic fields in a magnetic resonance imaging system comprising: positioning a plurality of conducting members in a region of interest, wherein the plurality of conducting members are electrically connected and form an RF coil array; positioning an RF shield in the region of interest, wherein the RF shield forms a partially closed volume; wherein at least one of the plurality of conducting members is located outside of the partially closed volume such that RF field produced by the at least one of the plurality of conducting members is shielded from the inside of the partially closed volume, wherein at least one of the remaining plurality of conducting members is located inside of the partially closed volume; and detecting magnetic fields with the plurality of conducting members.