Politecnico di Torino, I-10129, Torino, Italy.
Istituto Nazionale di Ricerca Metrologica, I-10135, Torino, Italy.
Sci Rep. 2017 Mar 23;7(1):326. doi: 10.1038/s41598-017-00215-7.
The number of people submitted to total hip or knee arthroplasty increased in the last years and it is likely to grow further. Hence, the importance of a proper investigation tool that allows to determine and recognize the potential presence of perioperative and/or postoperative diseases becomes clear. Although the Magnetic Resonance Imaging (MRI) technique demonstrated several advantages over the other common tomography tools, it suffers from the arise of image artefacts if it is performed in presence of metallic prostheses. In particular, the so-called RF-artefacts are caused by the inhomogeneity in the radiofrequency magnetic field of MRI, due to the electric currents induced on the metal surface by the field itself. In this work, a near-zero permittivity dielectric coat is simulated to reduce those currents and, therefore, the RF-artefacts onset in the final image. Numerical results confirm that the dielectric coat strongly reduces the magnetic field inhomogeneity, suggesting a possible solution to a well-known problem in the MRI field.
近年来，接受全髋关节或全膝关节置换术的人数有所增加，而且这一数字可能还会进一步增长。因此，需要一种合适的检查工具来确定和识别围手术期和/或术后疾病变得尤为重要。尽管磁共振成像（MRI）技术在其他常见的断层扫描工具中显示出了许多优势，但如果在存在金属假体的情况下进行 MRI 检查，它会产生图像伪影。具体来说，所谓的射频伪影是由 MRI 中射频磁场的不均匀性引起的，这是由于磁场本身在金属表面上感应出电流所致。在这项工作中，模拟了一种介电常数接近零的电介质涂层，以减少这些电流，从而减少最终图像中的射频伪影的出现。数值结果证实，电介质涂层强烈地降低了磁场的不均匀性，这为 MRI 领域的一个已知问题提供了一种可能的解决方案。
