Pens, bobby pins, hairclips, etc. 0000196689 00000 n Non–MR imaging personnel must undergo safety screening every time they enter zones III and IV and must be under the direct supervision of level 2 personnel at all times in zones III and IV. All MR imaging facilities should have a documented plan to handle emergencies within zone IV, including cardiac arrest or code, magnet quench, and fires, and all MR imaging personnel should be familiar with this plan. Newer-generation systems reduce noise levels by use of additional passive noise shields and active techniques such as noise-minimizing “silent” or “quiet” pulse sequences (38). Zone 4- This zone is the actual MRI scanner. 826 75 Reports of NSF in the pediatric patient population are rare (57). 5, Magnetic Resonance in Medical Sciences, Vol. This could be a computer-based module with a test, similar in format to that for MR imaging safety training for access to the MR imaging environment, printed educational material, a video of a lecture with documentation of completing this training, or a written test. 0000109623 00000 n Although the strongest magnetic field is at the isocenter of the magnet, the strongest forces are present where the gradient is largest. A burn has even been attributed to iron oxide particles within a patient’s wrist identification bracelet. 0000003619 00000 n Photograph shows the 5-G line along the floor of one of our MR imaging systems. However, abandoned intracardiac pacer wire leads lack such protection and are currently considered a contraindication to MR imaging. (b) Photograph shows a phased-array coil similar to the one involved in the incident. 0000018314 00000 n Access to zone III must be strictly restricted by lock or passkey systems, accessible and supervised only by MR imaging personnel. The anticipated benefits include the gaining of information that cannot be acquired by means of an alternate, nonionizing imaging modality and the detection of information that affects care of the patient or fetus during the pregnancy, without the possibility of waiting until after the pregnancy to obtain that information. 33, No. All MR imaging technologists and technologist aides must be level 2 personnel. (b) Photograph shows a phased-array coil similar to the one involved in the incident. If the address matches an existing account you will receive an email with instructions to reset your password. ■ List the different MR imaging safety zones and describe their restrictions. That incident resulted in third-degree burns and compartment syndrome that necessitated surgical release (26). Other devices have specific components that make them MR conditional or MR unsafe. GBCAs are excreted in minimal amounts in breast milk; amounts are estimated to be less than 0.04% of the total dose (54,55). SAR limits have also been declared for MR-conditional devices, specifically to reduce the risk of thermal injury. Daily QC activities include visual inspection of all scanner hardware, the function of safety and communication devices, and general assessment of image quality including identification of artifacts. The ACR Manual on MR Safety addresses numerous MR safety-related topics such as: If the patient’s eGFR is less than 45 mL/min/1.73 m2, we always perform a new eGFR calculation at the time of examination. 0000003968 00000 n This guide was intended for a broad audience, including MR physicists, supervisors, and hospital safety officers, and thus provides additional detail beyond what is expected for the typical practicing radiologist. A steel oxygen tank is never permitted inside of the MRI system room. Direct contact burn. Induced electrical currents can produce painful neurostimulation in patients. ACR Guidance Document on MR Safe Practices: 2013, and IEC 60601-2-33), and MR system manufacturer documentation. If such a decrease has occurred, we perform a point-of-care serum creatinine test at the time of examination to calculate a new eGFR. It should discuss that MR imaging uses powerful magnets and radiofrequency waves, which can pose several hazards to patients and staff members, including projectile effects, burns, auditory risks, and device malfunctions; safety screening; common implanted devices of concern; common objects that should not be brought into the MR imaging suite; MR imaging zoning; and emergency protocols in case of a quench or fire. Also recommended is that caution be used in administering GBCAs to neonates and infants because of their potentially low glomerular filtration rates and renal immaturity. Although most fragments do not pose any translational or rotational hazard, proximity to nearby vital structures may preclude imaging (15–17). When a magnetic object is placed in the field of an MR imaging unit, it is subject to translational force and/or torque. These guidelines were developed on the basis of established knowledge of electromagnetism as well as experience from adverse events. Many manufacturers also publish MR imaging safety information and guidelines for their devices on their Web sites. However, an informed decision should be made by the mother, including the option to temporarily suspend breast-feeding for 12–24 hours after GBCA administration (40). My predictions for 2019 are: 1. One of the level 2 personnel at each MR imaging site is the MR imaging medical director, whose job includes ensuring that MR imaging safe policies and procedures are established, updated, and followed by all staff members, as well as overseeing MR imaging safety issues that arise during the operation of the MR imaging site. 0000009489 00000 n 25, No. 4, Practical Radiation Oncology, Vol. Patients at the highest risk for a reaction to GBCAs are those with a history of reactions to the same agent and those who have experienced multiple other allergic reactions. Guidelines on appropriate monitoring and management in these cases are provided by the American Academy of Pediatrics and the American Academy of Pediatric Dentistry (56). Once the main magnetic field is established, it is left on and can remain stable at several hundred amperes for years, as long as the liquid helium level in the cryostat is sufficient to maintain the coil in a superconducting state. This causes a sudden increase in temperature throughout the entire main coil, leading to a rapid increase in electric resistance. Large transmit coils (eg, the body coil built into the bore) are capable of transmitting tens of kilowatts of radiofrequency power in short bursts. To achieve such currents in a conventional electromagnet would require a massive amount of continuous power. The possible risks, although not conclusively documented to be present, include but are not limited to the following: possible bioeffects of the static magnetic field of the MR imaging system, risks associated with exposure to the gradient magnetic fields, potential adverse effects of the radiofrequency energy, possible adverse effects related to the combination of these three magnetic fields, and possible effects of acoustic noise in the MR imaging environment on the fetus. Hence it is crucial to secure the magnet area after a quench to ensure that first responders enter the area safely and only if they are needed. The coil cable showed no indication of a burn. 0000018497 00000 n It is important to consult with the magnet vendor and the designer of the magnet suite to determine best practices in the event of a quench. The training for level 2 personnel includes the same material as for level 1 personnel, with the addition of more in-depth material on the safety screening process, the portable objects that can be brought into zone IV and the U.S. FDA labeling criteria for these, and the safety response and emergency procedures in the MR imaging environment. Electronic devices can interact in several ways with the main or gradient magnetic fields and the radiofrequency fields, potentially leading to adverse events. The FDA has classified GBCAs as pregnancy category C drugs, meaning that their safety in humans has not been proven but that they may be used in cases where the potential benefits outweigh the risks (61). 0000017811 00000 n Retained wires that are short and have no potential to form loops may be safe for MR imaging. 0000002576 00000 n However, the transmit radiofrequency coils, which, as discussed previously, can deposit very high power, can induce huge currents through the receive coil because both operate at the same resonant frequency. These incidents typically involve objects external to the patient—not infrequently, medical support equipment. 47, No. It is also vital for operators to understand the difference between the quench button and the emergency power shutoff or shutdown button, which shuts off many of the electrical systems surrounding the magnet without initiating a quench. Moreover, in our institution, all pregnant patients must sign an “MRI in Pregnant Patient” consent form provided by a physician (either from the radiology department or from the ordering service) before they undergo any MR imaging examination. Regulatory and professional society MR imaging safety guidelines have standardized many aspects of MR imaging site design, patient safety, and personnel workflow. %%EOF Temporary hearing loss has been documented in patients who underwent routine MR imaging examinations without protective devices (37). Perspiration resulted in greater contact between the skin surface and the compressed cable, which further increased conductivity (Fig 2). For example, programmable ventriculoperitoneal shunts may contain metallic or even magnetic parts that are used to adjust valve pressure settings in vivo, resulting in MR-conditional requirements. Newer magnets, such as this 1.5-T unit, use active shielding to bring the 5-G line as close as possible to the bore. 35, No. As field strengths increase, techniques for estimating and managing the SAR will become more critical for patient safety. Examples include surgical sutures, vascular and biliary stents, clips, plates, and screws. Engineering advancements and improvements in image processing continue to reduce operating costs and barriers to entry, which has increased the widespread use of MR imaging. In this space, individuals change from undifferentiated to candidates for the MRI exam. h. MR Zones. These rapid fluctuations in current result in microscopic movements of the coils, which lie within an audible frequency range; this is the source of the knocking and buzzing noises generated by an MR imaging unit during an examination. 46, No. Discover (and save!) 0000005816 00000 n Facebook; Twitter; Linked In; Contact details. Since the static magnetic field extends in three dimensions, some zones may extend into other areas or floors of Reducing the read bandwidth or increasing the repetition time can reduce dB/dt. Although patients and MR imaging personnel are the focus of many safety policies, greater hazards may be associated with individuals who are not patients and who do not regularly work in the MR imaging environment, as they may be more likely to unknowingly bring ferromagnetic materials into the MR imaging environment or accidentally bypass screening checkpoints (5). Hardbound MRI Textbook. Magnet rooms are generally equipped with a quench pipe that is intended to vent this boil-off safely out of the building. There have been several reported instances where cylinders filled with anesthetic gas or oxygen became projectiles, with one case resulting in death from a collision against the patient inside the magnet (18,19). This zone should be clearly marked (with a red light and a sign stating that the magnet is always on) as potentially hazardous because of the strong magnetic field (Fig 3). 3, Korean Circulation Journal, Vol. Policies in the United States are used throughout this article as an example. The FDA sets a maximum of 140 dB for an MR imaging system and a maximum of 99 dB for a patient with hearing protection (35). 0000009926 00000 n No adverse outcomes to fetuses have been reported after a review of studies in pregnant patients who received GBCAs, although the sample sizes of these studies were small (60). All MR imaging systems have a specific button that initiates this process. Thermal injury from MR imaging is uncommon, with 419 reported cases between 2000 and 2010 in the United States (23). 1, 3 March 2016 | Abdominal Radiology, Vol. For this reason, the coil of the main magnet is placed inside a well-insulated canister and is immersed in liquid helium. Careful screening is required to identify these at-risk patients. However, other devices require more caution. Practical guidance from experienced practitioners of MR imaging is included to help familiarize the reader with safety issues that commonly arise in MR imaging. Gradient coils are fixed in place relative to the main magnetic field coils and are typically installed within the magnet bore. If the patient’s eGFR is 30–45 mL/min/1.73 m2 and has decreased by 10 mL/min/1.73 m2 or is 15–29 mL/min/1.73 m2 and remains stable, we administer a Group III GBCA. At our institution, we incorporate the Choyke questionnaire, which enables screening for all of the risk factors listed above (except age >60 years), as well as for a history of proteinuria and a history of gout (51,52). 0000199458 00000 n Many of these devices are composed of nonferromagnetic materials that do not pose a risk of force-related injury. �j�_k�k8ۘ�t����Тk58�����Ej�S���4����R�]�?`����#V�n�0fO�&�S�H�V,+ŕ�>�����f��A*�$9|@��(IYL�(�RK��4�ϕ�K�V��)�pL�FCL�@�e�+����b ��ް0\�5D���!��!�"��!.���ԮZ�{��v�w/p�����&.�'n��t�e�&k���|�m�,qK����,?�e�whq�=�u�1�c���=k/�ߠgZ:q��4,�~QTH����yl���#,L����9��L�������l���y�뱪�z�n�D�cӃ3C��s#�����������婕HgCWcwSOs���j�H.H���j� Other emergency equipment within the MR imaging room, such as fire extinguishers, also needs to be MR safe or MR conditional. A recently published retrospective case-control study (59) on the safety of MR imaging at 1.5 T in 751 human fetuses showed no adverse effects of MR imaging exposure in utero on neonatal hearing function or birth weight percentiles. Sensitivity to peripheral neurostimulation varies widely among individuals, and it is possible that an imaging examination that is well tolerated by one patient will be uncomfortable for another. For example, some transdermal medicinal patches containing trace aluminum have caused superficial burns (24). However, there are now several MR-conditional pacemakers, made possible by decreasing the ferromagnetic components, using solid-state switches that are resistant to errant activation, and incorporating radiofrequency filters and lead designs to prevent resonant circuit burns (33). This requires use of strong magnetic fields and radiofrequency coils, which presents a set of safety challenges distinct from those of all other radiologic modalities. This Web site is frequently updated, and a hard-copy reference, which additionally covers the ACR, ASTM International, and FDA guidelines, is also available (11). Regulatory agencies continue to clarify existing standards to reduce or eliminate confusion when screening patients for MR imaging examinations. AUSTRALIA. hތQ�OSq�~]x/(�� Safety Guidelines for Magnetic Resonance Imaging Equipment in Clinical Use 5/85 1 Introduction 1.1 Background This is the 4th edition of the safety guidelines and aims to provide relevant safety information for users of magnetic resonance imaging (MRI) equipment in clinical use but will have some relevance in academic The main magnetic field of an MR imaging unit places unique constraints on how emergencies are handled inside an MR imaging suite, in particular within zone IV. A Closer Look at the Thresholds of Thermal Damage: Workshop Report by an ICNIRP Task Group (2016) (pdf) ACR Addresses FDA Gadolinium Safety Concerns (2016) ACR contrast media manual (2018) American College of Radiologists guidelines for contrast media; ACR Guidance Document on MR Safe Practices: 2020 (2013) 0000193990 00000 n The ACR has defined different levels of MR imaging personnel as follows (5): (a) level 1 MR imaging personnel—those who have passed minimal safety educational efforts to ensure their own safety as they work within zone III; (b) level 2 MR imaging personnel—those who have been more extensively trained and educated in the broader aspects of MR imaging safety issues; and (c) non–MR imaging personnel—all those not having successfully complied with MR imaging safety instruction. Therefore, the majority of MR imaging magnets use superconducting wire, which has essentially zero electrical resistance provided that it is maintained at a very low temperature. 0000008484 00000 n GBCAs are well tolerated by a majority of patients, and their safety profile is excellent and, by most measures, more favorable than those for iodinated contrast agents. 1, 18 July 2017 | Scientific Reports, Vol. The Joint Commission and/or the ACR require each institution to have written policies covering all of these topics. Only MR imaging personnel shall be provided free access to zone III, and non–MR imaging personnel are not to be provided with independent access until they undergo the proper education, training, and certification to become MR imaging personnel themselves. In these cases, a note from the patient’s surgeon may be required to confirm the details. All MR imaging safety principles apply to this patient population as they do for adults. More common are burns from electromagnetic induction, where generated current from changing magnetic fields produces an excessive amount of heat, analogous to an excessive local SAR. Level 1 personnel should also fill out a safety screening form that is kept on file and is confirmed to be accurate yearly. Enter your email address below and we will send you your username, If the address matches an existing account you will receive an email with instructions to retrieve your username. Nevertheless, caution should be exercised when considering MR imaging in a pregnant patient, and there should be a risk-benefit analysis of imaging alternatives before proceeding with the MR imaging examination. 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. At our institution, we have adopted a revised algorithm that uses a slightly different eGFR scale and incorporates same-day testing. Viewer, http://stats.oecd.org/index.aspx?DataSetCode=HEALTH_STAT, http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm107721.htm, http://www.fda.gov/MedicalDevices/default.htm, http://www.astm.org/Standard/standards-and-publications.html, http://www.acr.org/∼/media/ACR/Documents/PDF/QualitySafety/Resources/ContrastManual/2013_Contrast_Media.pdf, http://www.jointcommission.org/assets/1/6/HAP-CAH_DiagImag_Prepub_July2015release_20150105.pdf, MR. Implant: Rapid Evidence-Based Determination of Implant Safety Status, Diagnostic accuracy of MRI criteria in predilection of morbidly adherent placenta, A New Fire Hazard for MR Imaging Systems: Blankets—Case Report, Localization of damage in the human leg muscles induced by downhill running, Magnetic Resonance Imaging for Patients with Cardiac Implantable Electronic Devices: Reduced Concerns Regarding Safety, but Scrutiny Remains Critical, MR Labeling Information for Implants and Devices: Explanation of Terminology, MR Safety Controversies: Basic Concepts to Practical Implementation, Standardized MR Terminology and Reporting of Implants and Devices as Recommended by the American College of Radiology Subcommittee on MR Safety. Increasing overlap and matching of the safety requirements set by the Joint Commission, the ACR, and the FDA have helped to create a more cohesive set of safety requirements. Figure 2a. An annual requirement for technologists, in addition to their level 2 training, should be a continuing education program that covers these topics. 0000003814 00000 n At our institution, we are more conservative and require all level 1 personnel in zone IV to be under the direct observation of level 2 personnel. Radiologists and trainees who rarely enter the environment (eg, nuclear medicine physicians and trainees or interventional radiologists who may never enter zones III and IV) could be level 1 personnel, which would allow them to enter the MR imaging environment in an emergency. Delaying a nonemergent MR imaging examination in this case would bypass any potential safety issues and could eliminate imaging artifacts. 0000002954 00000 n Other than best practice documents, regulatory structures, and MR system documentation, the ABMRS does not endorse any third party materials for exam preparation 12 “Together with MR Site accreditation, the formation of the ABMRS now completes the logical extension of … A line called the 5-G line is often drawn around the bore to show this limit (Fig 1). Those that do contain some ferromagnetic materials may be deemed MR safe if the amount of material is too small to cause any substantial force or if the device is anchored securely (eg, most dental implants and orthopedic screws). 1, Journal of Magnetic Resonance Imaging, Vol. The FDA requires only that dB/dt be set to levels that do not result in peripheral neurostimulation, without a specific number (4). Arrow = approximate contact point. The ACR Committee on Drugs and Contrast Media considers a patient at risk for developing NSF in the following conditions (40): (a) undergoing dialysis; (b) chronic kidney disease stage 4 or 5 (eGFR <30 mL/min/1.73 m2) without dialysis; (c)eGFR of 30–40 mL/min/1.73 m2, without dialysis, due to potential short-term fluctuations in eGFR that may result in a level below 30 mL/min/1.73 m2; or (d) acute kidney insufficiency. The risk of peripheral neurostimulation is dictated by the rate of change of the magnetic field over time, termed dB/dt and expressed in teslas per second. Although no adverse effects to the fetus or neonate have been established, intravenously administered GBCAs are known to enter fetal circulation and to persist within the amniotic fluid. Newer MR-conditional electronic implants are now available with SARs and imaging time limits that are set by the manufacturer and are safe when specific conditions are followed. 0000017545 00000 n (1) Zone I. 5� i�h[Km�b D taU�B[�������-kA��h�Ƀ\�����#����$�p�D#�1���@K@�k���"�q9��S���Rv���gÙ���㒮�O��F����i�,3;'C�tVU���UjM���;���h�Zl:}���T�JV�rU�U�z���( �V�����qrRJ�](tT��8��oA������ ��8��ho�� Modern gradient systems can carry electrical currents of hundreds of amperes. Figure 4. Wires and leads—for example, electrocardiography cables or jewelry (eg, piercings)—can form an inductive circuit if they are accidentally coiled. During installation of the MR imaging unit, the current in the superconducting magnet is ramped up slowly to obtain the desired magnetic field strength, a process that takes several hours. Minimizing these risks, however, also requires application of this knowledge in a practical and effective manner. 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