Abstract: Systems and methods for the selection of and application of RF power to a plurality of transmit and/or transmit/receive coil elements to decrease patient SAR and to limit the potential for artifact problems. Without any change to the hardware or software of an MR scanner, the present local coil system provides system logic and coil design flexibility such that only transmit coil elements that are required for a particular portion of an MR scan will be utilized at that time. The local coil system may include any combination of transmit-only, receive-only and transmit/receive coil elements as part of the coil system (array of coil elements). The logic controller of the local coil system gathers input data from the MR scanner, from the attached coil elements and optionally from one or more sensors attached to the coil system itself.

Abstract: A birdcage coil for use with a magnetic resonance (MR) system comprises a first ring at one thereof, a second ring at the other end thereof, and a plurality of rods electrically interconnecting the first and second rings. The first ring is electrically conductive and has a first diameter. The second ring is electrically conductive and has a second diameter. The rods and first and second rings are configured to form about the birdcage coil a plurality of partially-overlapped primary resonant substructures. Each primary resonant substructure includes two of the rods and the corresponding sections of the first and second rings interconnecting them.

Abstract: An NMR magnetic coil system (10) is disclosed wherein the isolation between the coils (16, 18) can be adjusted to decrease or virtually eliminate the coupling between quadrature magnetic resonance imaging coils (16, 18). At least one of the coils (16) is separated into parallel segments (20, 22), located in a critically overlapped area. The capacitance of the segments is adjusted by a differential capacitor (76) to vary the ratio of the RF current flowing through the parallel segments. Appropriate adjustment of the capacitance of these paths (20, 22) causes a sharing of the appropriate amount of the out of phase flux to cancel the balance of the shared flux and therefore results in a net mutual inductance of zero.