Tsai Leo L, Grant Aaron K, Mortele Koenraad J, Kung Justin W, Smith Martin P
From the Department of Radiology, Beth Israel Deaconess Medical Center, 330 Brookline Ave, Boston, MA 02215.
Radiographics. 2015 Oct;35(6):1722-37. doi: 10.1148/rg.2015150108.
Magnetic resonance (MR) imaging can provide critical diagnostic and anatomic information while avoiding the use of ionizing radiation, but it has a unique set of safety risks associated with its reliance on large static and changing magnetic fields, high-powered radiofrequency coil systems, and exogenous contrast agents. It is crucial for radiologists to understand these risks and how to mitigate them to protect themselves, their colleagues, and their patients from avoidable harm and to comply with safety regulations at MR imaging sites. Basic knowledge of MR imaging physics and hardware is necessary for radiologists to understand the origin of safety regulations and to avoid common misconceptions that could compromise safety. Each of the components of the MR imaging unit can be a factor in injuries to patients and personnel. Safety risks include translational force and torque, projectile injury, excessive specific absorption rate, burns, peripheral neurostimulation, interactions with active implants and devices, and acoustic injury. Standards for MR imaging device safety terminology were first issued in 2005 and are required by the U.S. Food and Drug Administration, with devices labeled as "MR safe," "MR unsafe," or "MR conditional." MR imaging contrast agent safety is also discussed. Additional technical and safety policies relate to pediatric, unconscious, incapacitated, or pregnant patients and pregnant imaging personnel. Division of the MR imaging environment into four distinct, clearly labeled zones--with progressive restriction of entry and increased supervision for higher zones--is a mandatory and key aspect in avoidance of MR imaging-related accidents. All MR imaging facilities should have a documented plan to handle emergencies within zone IV, including cardiac arrest or code, magnet quench, and fires. Policies from the authors' own practice are provided for additional reference. Online supplemental material is available for this article.
磁共振（MR）成像能够提供关键的诊断和解剖学信息，同时避免使用电离辐射，但因其依赖大型静磁场和变化磁场、高功率射频线圈系统以及外源性造影剂，所以存在一系列独特的安全风险。对于放射科医生而言，了解这些风险以及如何降低风险至关重要，这样才能保护自己、同事和患者免受可避免的伤害，并遵守磁共振成像场所的安全规定。放射科医生需要具备磁共振成像物理和硬件的基础知识，以便理解安全规定的由来，并避免可能危及安全的常见误解。磁共振成像设备的每个组件都可能成为患者和工作人员受伤的因素。安全风险包括平移力和扭矩、投射物伤害、过高的比吸收率、灼伤、外周神经刺激、与有源植入物和设备的相互作用以及声学损伤。磁共振成像设备安全术语标准于2005年首次发布，美国食品药品监督管理局要求设备标注为“MR安全”“MR不安全”或“MR条件性”。本文还讨论了磁共振成像造影剂的安全性。此外，还有针对儿科、无意识、无行为能力或怀孕患者以及怀孕的成像人员的技术和安全政策。将磁共振成像环境划分为四个不同的、有明确标识的区域——随着区域级别升高，进入限制逐渐增加且监管加强——是避免磁共振成像相关事故的一项强制性关键措施。所有磁共振成像设施都应制定一份记录在案的计划，以应对IV区内的紧急情况，包括心脏骤停或急救、磁体失超以及火灾。文中提供了作者所在机构的相关政策以供参考。本文提供在线补充材料。
