RADIO FREQUENCY (RF) BIRDCAGE COIL WITH SEPARATELY CONTROLLED RING MEMBERS AND RUNGS FOR USE IN A MAGNETIC RESONANCE (MR) IMAGING SYSTEM

• US 20150276897A1
• Filed: 10/14/2013
• Published: 10/01/2015
• Est. Priority Date: 10/25/2012
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Leussler, Christoph, Wuelbern, Jan Hendrik
• Granted Patent: US 9,983,279 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 33/34076 Birdcage coils
• CPC Class Codes: G01R 33/3614 RF power amplifiers
• CPC Class Codes: G01R 33/3628 Tuning/matching of the transmit/receive coil
• CPC Class Codes: G01R 33/365 Decoupling of multiple RF coils wherein the multiple RF coils have the same function in MR, e.g. decoupling of a receive coil from another receive coil in a receive coil array, decoupling of a transmission coil from another transmission coil in a transmission coil array
• CPC Class Codes: G01R 33/5659 caused by a distortion of the RF magnetic field, e.g. spatial inhomogeneities of the RF magnetic field G01R33/56509, G01R33/56518, G01R33/56536 take precedence
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop

Abstract

A radio frequency (RF) antenna device (40) for applying an RF field to an examination space (16) of a magnetic resonance (MR) imaging system (10), the RF antenna device (40) comprising a plurality of rungs (42, 44) arranged substantially parallel and in an azimuthally substantially equally spaced relationship along an outside of a virtual cylinder (50) with a cylinder axis (52) running parallel to main directions of extension (48); at least one transversal antenna member (54) electromagnetically coupled to at least one rung (42, 44) of the plurality of rungs (42, 44), wherein the at least one transversal antenna member (54) is arranged within a plane substantially perpendicular to the main directions of extension (48) of the plurality of rungs (42, 44); and a plurality of RF circuitries (62, 64, 66), wherein at least one RF circuitry (62, 64, 66) is provided for each rung (42, 44) of the plurality of rungs (42, 44) for mutual decoupling and for individually feeding RF power into and for the at least one transversal antenna member (54) for individually feeding RF power into.

Claims

1. A radio frequency antenna device for applying an RF field to an examination space of a magnetic resonance (MR) imaging system, the RF antenna device comprising

a plurality of rungs made from an electrically conductive material, wherein each rung of the plurality of rungs has a main direction of extension, and wherein in an operational state, the main directions of extension of the plurality of rungs are arranged substantially parallel and in an azimuthally substantially equally spaced relationship along an outside of a virtual cylinder with a cylinder axis running parallel to the main directions of extension;

at least one transversal antenna member made from an electrically conductive material that is electromagnetically coupled to at least one rung of the plurality of rungs, wherein the at least one transversal antenna member, in the operational state, is arranged within a plane that is substantially perpendicular to the main directions of extension (48) of the plurality of rungs; and

a plurality of RF circuitries, wherein at least one RF circuitry of the plurality of RF circuitries is provided for each rung of the plurality of rungs for mutual decoupling and for individually feeding RF power into and for the at least one transversal antenna member for individually feeding RF power into.

2. The radio frequency antenna device as claimed in claim 1, wherein at least one rung of the plurality of rungs is split into at least two rung elements that are aligned in series in the main direction of extension of the rung.

3. The radio frequency antenna device as claimed in claim 1, wherein the at least one transversal antenna member has a substantially circular shape.

4. The radio frequency antenna device as claimed in claim 1, comprising at least two transversal antenna members that are substantially aligned on a virtual circular line lying in the plane.

5. The radio frequency antenna device as claimed in claim 1, comprising a plurality of transversal antenna members.

6. The radio frequency antenna device as claimed in claim 5, wherein the plurality of transversal antenna members is arranged to be aligned along at least two virtual circular lines, each virtual circular line lying in a plane, wherein the planes are arranged in parallel in a spaced manner in the main direction of extension.

7. The radio frequency antenna device as claimed in claim 1, wherein the number of rungs of the plurality of rungs equals the number of transversal antenna members arranged within a plane or within one of the planes.

8. The radio frequency antenna device as claimed in claim 7, wherein each rung of the plurality of rungs is electromagnetically decoupled from one of the transversal antenna members arranged within one plane or within one of the planes, and each of the transversal antenna members is electromagnetically decoupled from one rung of the plurality of rungs.

9. The radio frequency antenna device as claimed in claim 8, wherein a decoupling location between each rung of the plurality of rungs to one of the transversal antenna members arranged within one plane or within one of the planes, and a decoupling location between each of the transversal antenna members to one rung of the plurality of rungs is provided at a center portion of the respective transversal antenna members and an end portion of the respective rung.

10. The radio frequency antenna device as claimed in claim 1, wherein each of the RF circuitries of the plurality of RF circuitries comprises at least one RF source that is provided for applying RF power to at least one out of a rung of the plurality of rungs or the at least one transversal antenna.

11. The radio frequency antenna device as claimed in claim 7, further comprising a single RF source and at least one RF power divider, wherein the single RF source is provided for individually feeding RF power to the plurality of rungs and to at least one transversal antenna member via the at least one RF power divider.

12. The radio frequency antenna device as claimed in claim 1, wherein the rungs and the transversal antenna members (54) are designed as TEM-type resonator strips.

13. A magnetic resonance imaging system, comprising:

a main magnet for generating a substantially static magnetic field;

a magnetic gradient coil system for generating gradient magnetic fields superimposed to the static magnetic field;

an examination space provided to position a subject of interest within;

at least one RF antenna device as claimed in claim 1 that is provided for applying an RF field to the examination space (16) to excite nuclei of the subject of interest.