High-T/sub c/ superconducting surface coil for 2 tesla magnetic resonance imaging of small animals

The performance of small-volume Magnetic Resonance Imaging (MRI) depends on the system noise determined by noise of a probe and/or of a preamplifier (not by the body noise). Several demonstrations confirmed that, for selected applications, high-T/sub c/ superconductor MRI receiver coils have superior properties to those of comparable copper coils. We report on the outstanding performance of modified twin horseshoe YBCO rf surface probes in a 2 Tesla scanner operating at 77 K. They were used for MR imaging of spinal cord injuries in rats and for imaging of brain of small animals. The probes were designed with a virtual ground plane, thus reducing the coil-to-ground dielectric losses and making its resonant frequency less sensitive to the body proximity. Each coil was fabricated using large area 500 nm thick double-sided YBa/sub 2/Cu/sub 3/O/sub x/ films deposited on sapphire r-cut substrates. We compare the performance of the 2 Tesla high critical temperature superconductor (HTS) probe with that made of a copper coil. Designing and cryo-packaging of HTS MRI probes is discussed.