High-Tc Superconducting Surface Coil for 2 Tesla Magnetic Resonance Imaging of Small Animals

T h e p e r f o r m a n c e o f s m a I I v o I u m e Magnetic Resonance Imaging ( M R I ) d e p e n d s on t h e s y s t e m n o i s e determined by noise of a probe and/or of a preamplifier (not by the body noise). Several demonstrations confirmed that, for selected applications, high-TC superconductor MRI receiver coils have superior properties to those of comparable copper coils. W e report on the outstanding performance of modified twin horseshoe Y B C O r f surface probes in a 2 Tes la s c a n n e r 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 YBaZCu30, films deposited on sapphire r-cut substrates. W e c o m p a r e t h e p e r f o r m a n c e o f t h e 2 T e s l a high critical temperature superconductor (HTS) probe with that made of a copper coil. Designing and cryo-packaging of HTS MRI probes is discussed.