Radiologists Address the Most Common Safety Issues for MRI
Education and awareness are key to preventing MRI-related incidents
Over the past twenty years, the field of MRI safety has grown. There have been widespread efforts to standardize safety protocols in MRI environments, including required institutional safety operations. However, it is often the lack of knowledge about MRI safety protocols and guidelines that result in incidents, according to Emanuel Kanal, MD, professor of radiology and neuroradiology, and director of MR Education and MR Services at the University of Pittsburgh Medical Center.
“Unlike most surgery or many medications, MRI, while complex, carries very little risk, is relatively safe, and is invaluable to the diagnosis and treatment of patients,” Dr. Kanal stated. “However, when someone is hurt during MRI, the injury was almost always avoidable.”
Preventing avoidable MRI injuries starts with understanding the modality and how it can cause harm—no matter how unlikely.
Lowering The Incidence of Burns
According to the FDA, second-degree burns are the most reported MRI safety issue. Burns associated with the MRI’s radiofrequency (RF) field can occur in a variety of ways, the most obvious of which is when a patient comes in contact with the bore during scanning.
“A bedsheet alone won’t protect a patient from near field burns; you must use insulated pads that are about an inch thick to ensure the patient isn’t burned due to unsafe proximity to the bore,” advised Robert E. Watson, Jr., MD, PhD, associate professor of radiology at Mayo Clinic, Rochester, MN, chair of the American Board of MR Safety (ABMRS), and chair of the American College of Radiology (ACR) MR Safety Committee. “This is especially important if the patient is under anesthesia. If insulating padding slips out of place as when the patient is being advanced into the magnet, a body part could contact the bore and a severe burn could result, especially because the patient won’t react to the heating.”
Dr. Watson reminded technologists and radiologists to make sure patients’ thighs or other body parts aren’t touching because points of skin-to-skin contact could be sites of heating and burns due to RF energy-induced current loops within the body. The same goes for any wires or leads in the bore touching the skin.
Colin Segovis, MD, PhD, director of MRI quality and safety and assistant professor of radiology and imaging sciences at Emory University School of Medicine, Atlanta, also noted that burns occur when patients don’t change into hospital-approved gowns prior to entering the machine.
“Today, fabrics used for undergarments and athletic clothing are made with copper fibers meant to hide odor,” Dr. Segovis explained. “In the MRI, metallic fibers burn patients, so it is important that they put on approved clothing prior to a scan.”
“Radiologists and the technologists in the imaging suite need to position themselves as MR experts and resources for their colleagues. By working together, we can deliver the best care for our patients.”
KIANA LEBEL, MD
Avoiding Projectile Incidents
Another cause of MR-related injuries and deaths is projectiles. This occurs when ferromagnetic objects like some oxygen canisters are pulled across the room toward the MRI scanner at high speeds and collide with someone in the room.
“An MRI scanner is an incredibly powerful magnet, and the magnet is always on even if the machine isn’t running,” Dr. Segovis said. “This is such an important awareness and safety concept to ensure that anyone who works in the imaging suite understands.”
Dr. Watson agreed and mentioned the importance of establishing protocols around MRI safety zones.
The American College of Radiology has defined four safety zones with MRI facilities. They are labeled as Zones 1 through 4 and correspond to the levels of increasing magnetic field exposure. (See box below with MRI safety zones.)
“Zone 4 houses the MRI itself, and it can be thought of as the ‘magnet room’ and the ‘projectile zone.’ If someone walks into Zone 3 with an unsafe ferromagnetic object and the door to Zone 4 is open and unprotected, this sets the stage for a serious projectile incident,” Dr. Watson said. “Appropriate use of ferromagnetic detection systems can help lessen this risk.”
MRI Safety Zones
The American College of Radiology has denoted four safety zones within MRI facilities designating areas with increasing magnetic field exposure.
MRI Zone 1
These areas are freely accessible to the general public, patients and health care team members without supervision. The magnetic fringe fields in this area are very low to none.
MRI Zone 2
This is still a public area but is getting closer to Zones 3 and 4. MRI patient screening and preparation typically happen in these areas.
MRI Zone 3
This area has restricted access only for screened patients and health care team members. This is near the magnet room and can potentially present a physical hazard to those unscreened.
MRI Zone 4
Often called the “magnet room,” this area houses the MRI, has the highest strength magnet fields and the greatest risk for hazards, such as projectile accidents or injury to patients with implanted devices.
Understanding Recommendations on Implanted Devices
Radiologists don’t need to be aware only of metal on the patient’s body; they also need to understand what’s in the patient’s body. Some implanted devices can endanger a patient’s life if scanning is performed in an unsafe manner.
Implanted devices fall into one of three categories: MRI safe, MRI unsafe or MRI conditional. It is estimated that as many as 75% of patients with cardiac implanted electronic devices (CIEDs), such as pacemakers and defibrillators, will need an MRI at some point in their life.
While historically MRI unsafe, many newer CIEDs and their intracardiac leads now have MRI conditional labeling. In recent years, there is growing evidence supported by many societies, including the International Society for Magnetic Resonance in Medicine, the Heart Rhythm Society and the ACR MR Safety Committee, that patients with cardiac devices labelled MRI unsafe may still safely be scanned in a controlled environment. This means programming the CIED properly, scanning with the proper MR conditions and monitoring the patient throughout. An increasingly large body of data now indicates that other CIED systems not labeled as MRI conditional can also be scanned safely in patients with demonstrated medical necessity, providing there is a collaborative radiology/cardiology approach.
“In order to enter Zone 4, pacemakers need to be set to MRI-safe mode,” said Stephanie Tan, MD, a thoracic radiologist at the Montreal Heart Institute. “Hospitals and imaging centers should have protocols in place where the cardiologist adjusts the settings on patients’ pacemakers before and after each scan to ensure patient safety.”
Focusing on MRI Safety Awareness
While burns, projectiles and implanted devices are the most widely reported causes of MRI-related injuries and deaths, many radiologists agree that the real underlying danger is a lack of education, communication and standardization around MRI safety. To address this, many organizations and societies, including RSNA, include dedicated MR safety sessions in their annual meetings.
The ACR MR Safety Committee periodically updates the Manual on MR Safety and the American Board of Magnetic Resonance Safety (ABMRS) provides formal exams for candidates to demonstrate their knowledge specific to MR safety roles.
Understanding the MRI safety zones and setting up comprehensive protocols is essential, and many agree that having certified MR medical directors, MR safety officers and MR safety experts on staff is vital to create a safe environment.
“Radiologists and the technologists in the imaging suite need to position themselves as MR experts and resources for their colleagues,” noted Kiana Lebel, MD, PGY1 radiology resident at Université de Montréal. “By working together, we can deliver the best care for our patients.”
Dr. Tan echoed Dr. Lebel’s comments, noting that by learning more about the modality, radiologists can image more efficiently.
“Although injuries rarely happen, when they do, people are injured unnecessarily,” Dr. Kanal added. “The key to avoiding these risks is education and standardization.”
For More Information
Read the RSNA position statements on Appropriate Utilization of Medical Imaging and Radiation Dose and Medical Errors, at RSNA.org/Media.
Visit the RSNA Online Learning Center for courses related to MRI safety, RSNA.org/LearningCenter.
To learn more about becoming certified as an MR safety professional, visit the American Board of Magnetic Resonance Safety (ABMRS), www.abmrs.com.