Quadrature rf coil for vertical field mri systems

Abstract

A quadrature RF coil assembly ( ) is employed for quadrature excitation and/or reception in an open or vertical field magnetic resonance apparatus. The quadrature RF coil ( ) includes a plurality of parallel rung elements ( ). A pair of electrical conductive end segments ( ) connect the plurality of rung elements. Capacitive elements (C , C ) interrupt a central rung element and the end segments. Preferably, the capacitive elements (C , C ) are arranged in a high-pass configuration such that the two highest resonant modes, an odd mode ( ) and an even mode ( ), are tuned to have peak responsivity to a common imaging frequency. The odd mode ( ) is responsive to magnetic fields which are normal to the coil ( ), while the even mode is responsive to magnetic fields which are parallel to the coil ( ) and perpendicular to the main magnetic field. In one embodiment, the quadrature coil ( ) is curved such that it is partially wrapped around a portion of a subject ( ) with the rung elements of the coil ( ) parallel to the main magnetic field B . The quadrature coil ( ) provides improved B field uniformity and greater tuning stability due to reduced localized electric field effects. The coil ( ) provides greater accessibility for interventional procedures conducted in a vertical field or open magnetic resonance imaging system.