IR4M, Université Paris-Sud, UMR8081, F-91405 Orsay, France.
J Magn Reson. 2012 Nov;224:61-70. doi: 10.1016/j.jmr.2012.09.003. Epub 2012 Sep 20.
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.
结合高磁场 MRI 扫描仪，小植入线圈可实现高分辨率成像，并与外部线圈相比局部提高 SNR。开发了用于在 7T 下对大鼠大脑进行活体 MRI 的专用小型灵活植入线圈。基于多匝传输线谐振器设计，它们使用铜微成型工艺和特定的金属-聚合物粘附处理在聚四氟乙烯（Teflon）基底上制造。通过聚二甲基硅氧烷（PDMS）封装使植入线圈具有生物相容性。使用低损耗正切材料可在基底内实现低介电损耗，并使用 PDMS 层减少与周围介质的寄生耦合。在 7T MRI 系统中使用感应耦合和专用的外部接收线圈实现了植入线圈，用于信号传输。由于植入线圈，在平面分辨率为（150μm）（2）的情况下获得的大鼠大脑的体内图像显示出线圈附近的高 SNR，从而可以可视化精细的脑结构。
