PinMed, Inc., Pittsburgh, PA, USA.
Department of Internal Medicine, The University of Iowa, Iowa City, IA, USA.
J Cardiovasc Magn Reson. 2019 Aug 5;21(1):47. doi: 10.1186/s12968-019-0558-z.
Rapid application of external defibrillation, a crucial first-line therapy for ventricular fibrillation and cardiac arrest, is currently unavailable in the setting of magnetic resonance imaging (MRI), raising concerns about patient safety during MRI tests and MRI-guided procedures, particularly in patients with cardiovascular diseases. The objective of this study was to examine the feasibility and safety of defibrillation/pacing for the entire range of clinically useful shock energies inside the MRI bore and during scans, using defibrillation/pacing outside the magnet as a control.
Experiments were conducted using a commercial defibrillator (LIFEPAK 20, Physio-Control, Redmond, Washington, USA) with a custom high-voltage, twisted-pair cable with two mounted resonant floating radiofrequency traps to reduce emission from the defibrillator and the MRI scanner. A total of 18 high-energy (200-360 J) defibrillation experiments were conducted in six swine on a 1.5 T MRI scanner outside the magnet bore, inside the bore, and during scanning, using adult and pediatric defibrillation pads. Defibrillation was followed by cardiac pacing (with capture) in a subset of two animals. Monitored signals included: high-fidelity temperature (0.01 °C, 10 samples/sec) under the pads and 12-lead electrocardiogram (ECG) using an MRI-compatible ECG system.
Defibrillation/pacing was successful in all experiments. Temperature was higher during defibrillation inside the bore and during scanning compared with outside the bore, but the differences were small (ΔT: 0.5 and 0.7 °C, p = 0.01 and 0.04, respectively). During scans, temperature after defibrillation tended to be higher for pediatric vs. adult pads (p = 0.08). MR-image quality (signal-to-noise ratio) decreased by ~ 10% when the defibrillator was turned on.
Our study demonstrates the feasibility and safety of in-bore defibrillation for the full range of defibrillation energies used in clinical practice, as well as of transcutaneous cardiac pacing inside the MRI bore. Methods for Improving MR-image quality in the presence of a working defibrillator require further study.
快速应用体外除颤，这是心室颤动和心脏骤停的关键一线治疗方法，目前在磁共振成像（MRI）环境中无法实现，这引起了人们对 MRI 检查和 MRI 引导下的程序期间患者安全的担忧，特别是在心血管疾病患者中。本研究的目的是检查在整个 MRI 孔内和扫描期间，使用体外除颤/起搏为整个临床有用的冲击能量范围进行除颤/起搏的可行性和安全性，将体外除颤/起搏作为对照。
使用商业除颤器（LIFEPAK 20，Physio-Control，雷德蒙德，华盛顿，美国）和定制的高压双绞线进行实验，该双绞线带有两个安装的谐振浮动射频陷阱，以减少除颤器和 MRI 扫描仪的发射。总共在 6 头猪上进行了 18 次高能（200-360 J）除颤实验，分别在磁体孔外、孔内和扫描期间进行，使用成人和儿科除颤垫。在两个动物的亚组中，除颤后进行心脏起搏（有捕获）。监测信号包括：垫下的高保真度温度（0.01°C，每秒 10 个样本）和使用 MRI 兼容的心电图系统的 12 导联心电图（ECG）。
所有实验均成功进行除颤/起搏。与磁体孔外相比，孔内和扫描期间的除颤期间温度更高，但差异较小（ΔT：0.5 和 0.7°C，p 值分别为 0.01 和 0.04）。在扫描期间，儿科与成人垫之间的除颤后温度趋于更高（p 值为 0.08）。当除颤器打开时，MR 图像质量（信噪比）下降约 10%。
我们的研究表明，在整个临床实践中使用的除颤能量范围内，在孔内进行除颤以及在 MRI 孔内进行经皮心脏起搏是可行和安全的。在存在工作除颤器的情况下提高 MR 图像质量的方法需要进一步研究。
