Immel Erwin, Melzer Andreas
BIOPHAN Europe GmbH, Castrop Rauxel, Germany.
Minim Invasive Ther Allied Technol. 2006;15(2):85-92. doi: 10.1080/13645700600641004.
Vascular implants can cause significant MR image artifacts due to the material (susceptibility artifact) or the electromagnetic characteristics (RF artifact). These artifacts are caused by the distortion of the magnetic field and interferences with the radio frequency (RF) waves of the MR imaging process. Void or complete vanishing of signals occurs in close proximity or inside implants. The artifacts can be minimized by using a material with low magnetic susceptibility and a design of the implant which avoids electrical conductive loops. But not all designs can be made loop-free and non conductive. A resonant circuit tuned to the Larmor frequency of the MR tomography overcomes the RF artifact and thus improves the visualization of the implant lumen. The paper reviews the state-of-the-art technology of the MR-signal improvement in implants lumen, with particular regard to the use of resonant circuits such as stents or Vena Cava Filter (VCF), with resonators in 1.0 Tesla and 1.5Tesla MRT.
血管植入物可能会因材料（磁敏感伪影）或电磁特性（射频伪影）而导致显著的磁共振图像伪影。这些伪影是由磁场畸变以及对磁共振成像过程中射频波的干扰引起的。在植入物附近或内部会出现信号缺失或完全消失的情况。通过使用具有低磁敏感性的材料以及避免导电回路的植入物设计，可以将伪影最小化。但并非所有设计都能做到无回路且不导电。一个调谐到磁共振断层扫描拉莫尔频率的谐振电路可以克服射频伪影，从而改善植入物管腔的可视化。本文综述了植入物管腔磁共振信号改善的最新技术，特别关注了诸如支架或腔静脉滤器（VCF）等带有谐振器的谐振电路在1.0特斯拉和1.5特斯拉磁共振成像中的应用。
