Keck School of Medicine, University of Southern California and Institute for Magnetic Resonance Safety, Education, and Research, Los Angeles, CA 90045, USA.
Washington University in St. Louis, St. Louis, MO 63105, USA.
Magn Reson Imaging. 2014 Feb;32(2):163-7. doi: 10.1016/j.mri.2013.10.009. Epub 2013 Oct 18.
Coronary artery stents are made from metallic mesh and, therefore, to ensure patient safety, these implants must be evaluated to determine risks associated with MRI. Recently, bioabsorbable scaffolds, which have metallic markers, have been developed for use in the coronary arteries. Because of the metallic materials, these implants may present issues for patients undergoing MRI. Therefore, the objective of this investigation was to assess MRI issues (i.e., magnetic field interactions, MRI-related heating, and artifacts at 3 T) for a new bioabsorbable, coronary artery scaffold with metallic markers.
A bioabsorbable, coronary artery scaffold (Mirage Microfiber Scaffold) underwent assessments for magnetic field interactions, MRI-related heating, and artifacts at 3-Tesla using standard techniques. MRI-related heating was evaluated with the scaffold placed in a gelled-saline-filled phantom and MRI was performed at an MR system reported, whole body averaged SAR of 2.9W/kg for 15 minutes. Artifacts were characterized using T1-weighted spin echo and gradient echo, pulse sequences.
There were no magnetic field interactions. The highest temperature rise was 1.6°C (highest background temperature rise, 1.6°C). Artifacts were relatively small in relation to the size and shape of this coronary artery scaffold. Notably, the lumen of the scaffold could be visualized on the GRE pulse sequence.
The results demonstrated that the coronary artery scaffold is acceptable (or "MR conditional," using current MRI labeling terminology) for a patient undergoing an MRI procedure at 3 T or less. To our knowledge, this is the first bioabsorbable, coronary artery scaffold that has been evaluated for MRI issues.
冠状动脉支架由金属网制成，因此，为确保患者安全，必须对这些植入物进行评估，以确定与 MRI 相关的风险。最近，开发了带有金属标记的可生物吸收支架，用于冠状动脉。由于这些植入物的金属材料，它们可能会给接受 MRI 的患者带来问题。因此，本研究的目的是评估具有金属标记的新型可生物吸收冠状动脉支架的 MRI 问题（即磁场相互作用、与 MRI 相关的加热和 3T 处的伪影）。
使用标准技术对可生物吸收的冠状动脉支架（Mirage Microfiber 支架）进行磁场相互作用、与 MRI 相关的加热和 3T 处的伪影评估。将支架放置在凝胶盐水填充的体模中评估与 MRI 相关的加热，并在报告的 MR 系统上进行 MRI，全身平均 SAR 为 2.9W/kg，持续 15 分钟。使用 T1 加权自旋回波和梯度回波脉冲序列对伪影进行特征描述。
没有磁场相互作用。最高温升为 1.6°C（最高背景温升为 1.6°C）。与这种冠状动脉支架的大小和形状相比，伪影相对较小。值得注意的是，支架的管腔可以在 GRE 脉冲序列上可视化。
结果表明，该冠状动脉支架可接受（或使用当前 MRI 标记术语为“MR 条件”）在 3T 或更低的 MRI 程序中接受检查的患者。据我们所知，这是第一个评估与 MRI 相关问题的可生物吸收冠状动脉支架。
