US20070168003A1 Medical device with an electrically conductive anti-antenna member

摘要

问题:MRI 64MHz激励场在bipolar pacing lead上诱发~±0.85A tissue电流,导致tissue接触点温升~6°C可致组织灼伤和electrode失效
方案:Lead内distal端串联RLC谐振电路(inductor并联capacitor±resistor),impedance matching至MRI激励频率形成blocking effect
效果:64MHz环境:tissue distal current从~±0.85A被大幅减少(FIG.5显示减少>80%);tissue温升从~~6°C(无circuit)降至~~0.9°C(distal-positioned circuit,3.75min);低频pacing signal(<10Hz)幅度保持不变
形态:权利要求30+条,可调维度:resonant circuit位置(proximal/distal/线圈内嵌)、频率设计(64MHz/128MHz或多频点)、L/C值(如1.5T:L=124.2nH/C=31.06pF)、series resistance、thermal dissipation材料