Active optical decoupling circuit for radio frequency endoluminal coil

International audienceDespite the enhanced image provided by multiple-channels array coils, an accurate exploration of bowel diseases and detailed information about the gastrointestinal wall layers are still not available. The use of endoluminal RF coil located in the region of interest could potentially allow good evaluation of tumor invasion or depth of inflammatory processes [1]. However, since metallic coaxial cables are used, patient safety is threatened due to local electric field concentration that can happen and the associated local high Specific Absorption Rate (SAR) [2]. Moreover, in this case, cable isolation and traps cannot be straightforwardly employed due to limited dimension. Signal transmission based onoptical fiber is an alternative to coaxial cables to solve definitively the electromagnetic issues. On a receiver coil, both signal transmission and decoupling have to be insured. For MR signal transmission, the electro-optical conversion has been partially validated based on electro-optic effect of some crystals [3]. In this work, an active optical decoupling circuit for endoluminal coil is presented and compared to a reference coil with regular decoupling using bias signal though coaxial cable