title: Implanted, inductively-coupled, radiofrequency coils fabricated on flexible polymeric material: application to in vivo rat brain MRI at 7 T.
abstract: Combined with high-field MRI scanners, small implanted coils allow for high resolution imaging with locally improved SNR, as compared to external coils. Small flexible implantable coils dedicated to in vivo MRI of the rat brain at 7 T were developed. Based on the Multi-turn Transmission Line Resonator design, they were fabricated with a Teflon substrate using copper micromolding process and a specific metal-polymer adhesion treatment. The implanted coils were made biocompatible by PolyDimethylSiloxane (PDMS) encapsulation. The use of low loss tangent material achieves low dielectric losses within the substrate and the use of the PDMS layer reduces the parasitic coupling with the surrounding media. An implanted coil was implemented in a 7 T MRI system using inductive coupling and a dedicated external pick-up coil for signal transmission. In vivo images of the rat brain acquired with in plane resolution of (150 μm)(2) thanks to the implanted coil revealed high SNR near the coil, allowing for the visualization of fine cerebral structures.
authors.affiliation: IR4M, Université Paris-Sud, UMR8081, F-91405 Orsay, France. jean-christophe.ginefri@u-psud.fr
authors.forename: J-C
authors.initials: JC
authors.lastname: Ginefri
authors.forename: A
authors.initials: A
authors.lastname: Rubin
authors.forename: M
authors.initials: M
authors.lastname: Tatoulian
authors.forename: M
authors.initials: M
authors.lastname: Woytasik
authors.forename: F
authors.initials: F
authors.lastname: Boumezbeur
authors.forename: B
authors.initials: B
authors.lastname: Djemaï
authors.forename: M
authors.initials: M
authors.lastname: Poirier-Quinot
authors.forename: F
authors.initials: F
authors.lastname: Lethimonnier
authors.forename: L
authors.initials: L
authors.lastname: Darrasse
authors.forename: E
authors.initials: E
authors.lastname: Dufour-Gergam
mesh_terms: D000818:Animals; D001921:Brain / Q000033:anatomy & histology*; D055119:Elastic Modulus; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D008422:Materials Testing; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D011108:Polymers / Q000737:chemistry*; D019736:Prostheses and Implants; D051381:Rats; D017207:Rats, Sprague-Dawley; D013686:Telemetry / Q000295:instrumentation*
chemical_list: D011108:Polymers