Biplanar rf coil for magnetic resonance imaging systems

Abstract

A superconducting magnet (10) generates a uniform, static magnetic field through a central bore (12) along its longitudinal or z-axis. A biplanar gradient coil assembly (44) is inserted into the bore to create gradients across the static magnetic field along orthogonal x, y, and z-axes. A biplanar radio frequency coil assembly (50, 80) is inserted into the bore for transmitting radio frequency signals into a subject and receiving magnetic resonance signals from the subject. The radio frequency coil includes a first biplanar coil assembly (50) for generating RF signals in an x-direction and a second biplanar coil assembly (80) for generating RF signals in a y-direction. The two biplanar coil assemblies each include a plurality of conductors (52, 82) along a first plane and a second plurality of conductors (54, 84) along a parallel second plane. The conductors extend parallel to the z-direction. Capacitors (56, 58, 94) are connected in series with each of the conductors in order to control the current flow such that the current flow in each plane is uniform across the plane. The ends of the electrical conductors are connected together (66, 88) such that the current flows are equal and opposite in the two planes. A radio frequency transmitter (136) transmits RF signals to the quadrature biplanar coil assembly. A digital receiver (140) receives and demodulates radio frequency signals from the quadrature coil assembly. The demodulated signals are reconstructed (144) into an image representation for display on a video monitor (146).