Design of Actively Decoupled Implant Coil System with Improved B1 Homogeneity in Rat Spinal Cord

Andrew C.H. Yung¹, Nathan Wolfe¹, Tinny Lai¹, Lynn Tsai¹, Jenny C.H. Tso¹, Jie Liu¹, Piotr Kozlowski¹

A receive-only actively-decoupled implanted coil system (in combination with birdcage coil for transmission) which requires no decoupling circuitry on the implant is described. During reception, the implant overcouples with the pickup coil and produces a split resonance that operates at the Larmor frequency. During transmission, the pickup is detuned via PIN diode, while the uncoupled implants frequency response reverts to a single peak away from the Larmor frequency. In vivo experiments on rat spinal cord compare performance between the proposed system and the pickup-implant system operating in TX/RX. Flip angle uniformity is improved while maintaining comparable SNR.