Loyola Marymount University, Los Angeles, CA 90045, USA.
Magn Reson Imaging. 2013 Jan;31(1):145-9. doi: 10.1016/j.mri.2012.06.015. Epub 2012 Aug 14.
Fine-mesh braided, stent-like structures (flow diverters) have been proposed for treatment of brain aneurysms. To date, the safety of performing magnetic resonance imaging (MRI) in patients with these implants is unknown. Therefore, the purpose of this study was to evaluate MRI issues at 3-T for a new flow-diverting implant used to treat brain aneurysms.
The Surpass NeuroEndoGraft (Surpass Medical, Ltd., Tel Aviv, Israel) underwent evaluation for magnetic field interactions, MRI-related heating and artifacts using standardized techniques. Magnetic field interactions were assessed for this implant with regard to translational attraction (i.e., using the deflection angle technique) and torque (qualitative assessment method). MRI-related heating was evaluated by placing the implant in a gelled-saline-filled, head/torso phantom and performing MRI using a transmit/receive radiofrequency body coil at a whole-body-averaged specific absorption rate of 2.9 W/kg for 15 min. Artifacts were characterized using T1-weighted, spin echo (SE) and gradient echo (GRE) pulse sequences.
The Surpass NeuroEndoGraft exhibited minor magnetic field interactions (21° deflection angle and no torque), which were acceptable from a safety consideration. Heating was not substantial, with the highest temperature change being 2.3°C (background temperature rise without the implant was 1.5°C). Artifacts may create issues if the area of interest is in the same area or close to this implant.
The findings demonstrated that it would be acceptable for patients with this next-generation, flow-diverting implant to undergo MRI at 3-T or less.
编织的精细网眼状、支架样结构（血流导向装置）已被提议用于治疗脑动脉瘤。迄今为止，尚不清楚这些植入物的患者进行磁共振成像（MRI）的安全性。因此，本研究的目的是评估用于治疗脑动脉瘤的新型血流导向装置在 3-T 下的 MRI 问题。
使用标准化技术对 Surpass NeuroEndoGraft（Surpass Medical，Ltd.，Tel Aviv，Israel）进行磁场相互作用、与 MRI 相关的加热和伪影评估。使用偏转角技术评估了该植入物的磁场相互作用的平移吸引力，以及扭矩（定性评估方法）。通过将植入物置于凝胶盐水填充的头部/躯干体模中，并在全身平均比吸收率为 2.9 W/kg 的情况下使用发射/接收射频体线圈进行 15 分钟的 MRI 来评估与 MRI 相关的加热。使用 T1 加权、自旋回波（SE）和梯度回波（GRE）脉冲序列来描述伪影。
Surpass NeuroEndoGraft 表现出较小的磁场相互作用（21°偏转角和无扭矩），从安全性角度考虑是可以接受的。加热不明显，最高温度变化为 2.3°C（无植入物时的背景温度升高为 1.5°C）。如果感兴趣区域在同一区域或靠近该植入物，则可能会产生伪影问题。
研究结果表明，对于接受这种新一代血流导向装置的患者，在 3-T 或更低场强下进行 MRI 是可以接受的。
