Sommer T, Luechinger R, Barkhausen J, Gutberlet M, Quick H H, Fischbach K
Department of Diagnostic and Interventional Radiology, German Red Cross Hospital Neuwied, Germany.
Institute for Biomedical Engineering, Swiss Federal Institute of Technology (ETH Zurich) / University of Zurich, Switzerland.
Rofo. 2015 Sep;187(9):777-87. doi: 10.1055/s-0035-1553337. Epub 2015 Aug 26.
The aim of this paper is to inform physicians, especially radiologists and cardiologists, about the technical and electrophysiological background of MR imaging of patients with implanted cardiac pacemakers (PM) and to provide dedicated clinical practice guidelines how to perform MR exams in this patient group. The presence of a conventional PM system is not any more considered an absolute contraindication for MR imaging. The prerequisites for MR imaging on pacemaker patients include the assessment of the individual risk/benefit ratio as well as to obtain full informed consent about the off label character of the procedure and all associated risks. Furthermore the use of special PM-related (e.g. re-programming of the PM) and MRI-related (e.g. limitation of whole body SAR to 2 W/kg) precautions is required and needs to be combined with adequate monitoring during MR imaging using continuous pulsoximetry. MR conditional PM devices are tested and approved for the use in the MR environment under certain conditions, including the field strength and gradient slew rate of the MR system, the maximum whole body SAR value and the presence of MR imaging exclusion zones. Safe MR imaging of patients with MR conditional PM requires the knowledge of the specific conditions of each PM system. If MR imaging within these specific conditions cannot be guaranteed in a given patient, the procedure guidelines for conventional PM should be used. The complexity of MR imaging of PM patients requires close cooperation of radiologists and cardiologists.
Conventional pacemaker systems are no longer an absolute but rather a relative contraindication for performing an MR examination. The procedural management of conventional pacemaker includes the assessment of the individual risk/benefit ratio, comprehensive patient informed consent about specific related risks and "off label" use, extensive PM- and MRI-related safety precautions as well as adequate monitoring techniques during the MR exam. Decisive for patient safety are precise understanding of, and compliance with, the terms of use for the specific MR-conditional pacemaker system. If the electrophysiological and MRI-specific conditions for use of MR-conditional pacemakers are not met or compliance with these conditions for use cannot be guaranteed, the device must be treated like a conventional pacemaker.
本文旨在让医生，尤其是放射科医生和心脏病专家了解植入心脏起搏器（PM）患者的磁共振成像（MR）的技术和电生理背景，并提供关于如何对该患者群体进行MR检查的专门临床实践指南。传统PM系统不再被视为MR成像的绝对禁忌证。对起搏器患者进行MR成像的先决条件包括评估个体风险/受益比，以及就该检查的非适应证性质和所有相关风险获得充分知情同意。此外，需要采取与PM相关的特殊预防措施（如对PM进行重新编程）和与MRI相关的预防措施（如将全身比吸收率限制在2W/kg），并需要在MR成像期间使用连续脉搏血氧饱和度监测进行充分监测。MR条件性PM设备经过测试并批准在特定条件下用于MR环境，这些条件包括MR系统的场强和梯度切换率、最大全身比吸收率值以及MR成像禁区的存在。对具有MR条件性PM的患者进行安全的MR成像需要了解每个PM系统的具体条件。如果在特定患者中无法保证在这些特定条件下进行MR成像，则应采用传统PM的检查指南。PM患者MR成像的复杂性需要放射科医生和心脏病专家密切合作。
传统起搏器系统不再是进行MR检查的绝对禁忌证，而是相对禁忌证。传统起搏器的程序管理包括评估个体风险/受益比、就特定相关风险和“非适应证”使用向患者提供全面知情同意、采取广泛的与PM和MRI相关的安全预防措施以及在MR检查期间采用充分的监测技术。对患者安全起决定性作用的是对特定MR条件性起搏器系统使用条款的精确理解和遵守。如果不满足MR条件性起搏器使用的电生理和MRI特定条件，或无法保证遵守这些使用条件，则该设备必须被视为传统起搏器进行处理。
