Boutin R D, Briggs J E, Williamson M R
Department of Radiology, University of New Mexico, School of Medicine, Albuquerque 87131-5336.
AJR Am J Roentgenol. 1994 Jan;162(1):189-94. doi: 10.2214/ajr.162.1.8273663.
The purpose of this study was to survey the methods used by academic institutions for identifying patients who might have metallic foreign bodies or other contraindications to MR imaging. We also sought to determine the types of MR-related injuries and any subsequent legal action that might have occurred at these institutions.
A survey on these issues was mailed to 207 academic institutions listed in the American Medical Association's Directory of Graduate Medical Education Programs. Institutions that did not respond by mail were contacted by phone. The survey requested information on the use of questionnaires, plain radiography, CT, and metal detectors for screening potential MR imaging subjects, as well as on any MR-related injuries and subsequent legal action. Responses were entered into a data base and response percentages were calculated for each question.
The overall response rate for the survey was 99% (206/207). These 206 institutions have a total of 368 MR imaging units, with a mean number of 1.8 MR units per department (range, none to nine). Data from a total of 205 different sites revealed that all patients are screened before MR imaging with a written questionnaire at 93% of all institutions (190/205). For selected indications, 85% of departments (174/205) screen with plain film radiography of the orbits. For selected indications, 41% of facilities (83/205) screen with CT of the orbits. Patients are sometimes screened with a metal detector or magnetometer in 12% of the departments (24/205). Ten departments reported serious injuries relating to MR imaging. The most serious injury occurred when an oxygen tank near the magnet became a missile and struck a patient's face. Most injuries (nine of 14) were burns. Two institutions also reported adverse reactions to gadopentetate dimeglumine. Injuries prompted legal action against four of the 10 institutions. No injuries were related to intraorbital foreign bodies, vascular clips, or pacemakers in patients.
These data demonstrate the lack of consensus on screening protocols before MR imaging. Accidents are uncommon, but most accidents that do occur are potentially severe and easily preventable. We recommend that all patients be screened by a written questionnaire followed by oral questioning before imaging to determine those who are at risk. Specific questions should investigate the possibility that patients have ferromagnetic foreign bodies or implants anywhere in the body that are electrically, magnetically, or mechanically activated. All facilities must maintain a high state of vigilance in an effort to prevent iatrogenic burns and injuries from ferromagnetic missiles.
本研究旨在调查学术机构用于识别可能有金属异物或其他磁共振成像（MR）禁忌证患者的方法。我们还试图确定这些机构发生的与MR相关的损伤类型以及任何后续法律诉讼情况。
就这些问题向美国医学协会研究生医学教育项目名录中列出的207家学术机构邮寄了调查问卷。未通过邮件回复的机构通过电话进行了联系。该调查要求提供有关使用问卷、X线平片、CT和金属探测器对潜在MR成像对象进行筛查的信息，以及任何与MR相关的损伤和后续法律诉讼情况。将回复录入数据库，并计算每个问题的回复百分比。
调查的总体回复率为99%（206/207）。这206家机构共有368个MR成像单元，每个科室的MR单元平均数为1.8个（范围为0至9个）。来自总共205个不同地点的数据显示，93%的机构（190/205）在进行MR成像前通过书面问卷对所有患者进行筛查。对于特定指征，85%的科室（174/205）通过眼眶X线平片进行筛查。对于特定指征，41%的机构（83/205）通过眼眶CT进行筛查。12%的科室（24/205）有时会用金属探测器或磁力计对患者进行筛查。10个科室报告了与MR成像相关的严重损伤。最严重的损伤发生在磁体附近的一个氧气罐变成导弹并击中患者面部时。大多数损伤（14例中的9例）为烧伤。两家机构还报告了对钆喷酸葡胺的不良反应。损伤导致对10家机构中的4家提起了法律诉讼。患者中没有损伤与眶内异物、血管夹或起搏器有关。
这些数据表明在MR成像前的筛查方案上缺乏共识。事故并不常见，但大多数发生的事故可能很严重且易于预防。我们建议在成像前通过书面问卷然后进行口头询问对所有患者进行筛查，以确定有风险的患者。具体问题应调查患者体内任何部位是否存在铁磁性异物或可被电、磁或机械激活的植入物的可能性。所有机构必须保持高度警惕，努力预防医源性烧伤和铁磁性导弹造成的损伤。
