Supplementary Material for: The introduction of an MR-conditional prototype for cardiopulmonary bypass support – technical aspects and system requirements

Abstract Introduction: The use of cardiopulmonary bypass (CBP; also known as a heart-lung machine) in newborns with complex congenital heart defects may result in brain damage. Magnetic resonance imaging (MRI) assessments cannot be performed safely because the metal components used to construct CBP devices may elicit adverse effects on patients when they are placed in a magnetic field. Thus, this project aimed to develop a prototype MR-conditional circulatory support system that could be used to perform cerebral perfusion studies in animal models. Methods: The circulatory support device includes a roller pump with two rollers. The ferromagnetic and most of the metal components of the roller pump were modified or replaced and the drive was exchanged by an air-pressure motor. All materials used to develop the prototype device were tested in the magnetic field according to the American Society for Testing and Materials (ASTM) Standard F2503-13. The technical performance parameters, including runtime/durability as well as achievable speed and pulsation behavior, were evaluated and compared to standard requirements. The behavior of the prototype device was compared with a commercially available pump. Results: The MRI-conditional pump system produced no image artifacts and could be safely operated in the presence of the magnetic field. The system exhibited minor performance-related differences when compared to a standard CPB pump, feature testing revealed that the prototype meets the requirements (i.e., operability, controllability, and flow range) needed to proceed with the planned animal studies.

引言：针对合并复杂先天性心脏缺损的新生儿使用体外循环（cardiopulmonary bypass, CBP；又称人工心肺机）时，可能引发脑部损伤。由于体外循环装置的金属组件置于磁场中时可能对患者产生不良影响，因此无法安全开展磁共振成像（magnetic resonance imaging, MRI）评估。本项目旨在开发一款磁共振兼容型循环支持系统原型，用于在动物模型中开展脑灌注研究。
方法：本循环支持装置包含一台双滚轮滚压泵。研究人员对该滚压泵的铁磁性部件及多数金属组件进行了改造或更换，并将原驱动装置替换为气压马达。所有用于制作原型装置的材料均依据美国材料与试验协会（American Society for Testing and Materials, ASTM）标准F2503-13在磁场中完成测试。研究评估了该装置的技术性能参数，包括运行时长/耐用性、可实现转速及搏动特性，并与行业标准要求进行比对；同时将原型装置的性能与市售泵进行对比。
结果：该磁共振兼容泵系统不会产生图像伪影，可在磁场环境中安全运行。与标准体外循环泵相比，本系统仅存在轻微的性能相关差异；性能测试结果显示，原型装置满足后续计划开展动物研究所需的各项要求（即可操作性、可控性及流量范围）。