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  • Spike in MR Imaging Accidents Underscores Need for Regulation

    October 01, 2010

    A nurse entering an MR imaging system room watches helplessly as scissors fly from her hand, hitting a nearby patient in the head. A patient being placed in the magnet bore in an MR imaging unit is struck by an oxygen tank. After being wheeled into the scan room on a ferromagnetic gurney, a patient is pinned to the MR imaging system along with the gurney.

    Though none of these patients was seriously injured, the outcome of these MR-related incidents taken from the U.S. Food and Drug Administration's (FDA) Manufacturer and User Facility Device Experience (MAUDE) database could have been worse—even deadly. In fact, experts contend that a series of converging factors has created an environment that is ripe for MR-related accidents, heightening the need for increased vigilance in adopting MR imaging safety procedures and protocols.

    "At the moment, we have something of a perfect storm," said Tobias Gilk, an architect with the firm RADIOLOGY-Planning based in Kansas City, Mo., president and MRI Safety Director for Mednovus, Inc., based in Leucadia, Calif., and a former member of the American College of Radiology's (ACR) MRI Safety Committee. "The increasing number of MR procedures performed each year with increasingly strong MR magnets combined with reduced reimbursements, staff cuts, a shortage of experienced MR technologists and the lack of federal standards, add up to increased risk for MRI accidents."

    The 2008 FDA accident report data show a 310 percent increase in MR imaging-related incidents since 2004, the last year in which a decline in the number of such accidents was reported. In that time period, 482 MR imaging-related incidents were reported to the FDA.

    While the number of reported incidents pales in comparison to the estimated 30 million MR imaging studies performed annually in the U.S., experts say the FDA statistics don't tell the whole story and that the spike in accidents—combined with a lack of federal regulations for MR imaging procedures—has created a safety issue that should be on the radar of every radiologist.

    "It gets back to who is ultimately responsible for patient safety, and that is the radiologist," said Frank Shellock, Ph.D., founder of the Institute for Magnetic Resonance Safety, Education and Research (MRSER), a clinical professor of radiology and medicine and director of MRI studies of Biomimetic MicroElectronic Systems Implants at the University of Southern California in Los Angeles, and author of numerous books on MR imaging safety. "If radiologists are not even aware that some of these issues exist, that could be a huge problem."

    "Projectiles" are a Common Accident Cause

    Among the most common MR imaging-related accidents are "projectile" injuries, in which ferromagnetic objects—anything from oxygen canisters and wheelchairs to buckets, cribs and desk chairs—are pulled toward the MR imaging system room at a high speed, creating a "missile" effect. The most widely publicized incident of this type occurred in 2001, when a 6-year-old boy was killed after an oxygen tank brought into the MR imaging scanner room became magnetized and flew through the air at 20 to 30 feet per second, fracturing the boy's skull.

    "Not only is the patient at risk, but so is anyone who happens to be in the same room," according to Gilk, who created and maintains the MRI Metal Detector blog (see sidebar) featuring frequent posts and comments about MR imaging accidents. "There is an alarming number of injuries to MR technologists and service personnel."

    This poster warning of potential hazards in an MR imaging system room, can be downloaded at imrser.org and MRIsafety.com.
    Burn injuries—primarily related to radiofrequency coils, physiologic monitors, electronically activated devices and external objects made from conductive materials—are also common, while implanted devices pose another potential problem. ACR recommends that implanted cardiac pacemakers and implantable cardioverter/defibrillators be considered relative contraindications for MR imaging, because they can disrupt a pacemaker's electronic system and/or burn heart tissue that is in contact with the leads. This is likely to change with the U.S. release of MR-conditional pacemakers specially designed for use in patients undergoing MR imaging exams, according to Dr. Shellock. The cardiac implants are already available in Europe.

    Other MR imaging-related incidents might not ever get reported, according to Emanuel Kanal, M.D., director of Magnetic Resonance Services and professor of radiology and neuroradiology at the University of Pittsburgh Medical Center. Dr. Kanal contends that the FDA reporting system—which records information on medical devices that may have malfunctioned or caused a death or serious injury—is flawed.

    "While admittedly, the number of actual safety incidents/accidents is extremely difficult to accurately quantify, it is clear that the extreme majority of MR safety incidents do not make it to the FDA MAUDE database," said Dr. Kanal, whose extensive history with MR safety includes co-authoring a textbook with Dr. Shellock, and serving as an expert or consultant on hundreds of legal cases involving MR incidents in the past three decades and as the lead author on the ACR Guidance Document for Safe MR Practice. "In fact, the number of cases reported to me personally over the years is larger than what is in the FDA database, and very often these cases do not overlap."

    Along with a lack of standards for which events need to be reported and definitions for what constitutes a "serious" injury, Dr. Kanal said many radiologists do not how to report such incidents, while others fear such information could be used against them if legal action is taken. Ultimately, MR imaging-related incidents go underreported, Gilk said. "Essentially, we take the FDA numbers and multiply them by 100 and get much closer to a reasonable approximation of the true number of MR-related incidents."

    Mandatory Standards Not on the Horizon

    Although the ACR issued a guidance document for MR safety and the Joint Commission in 2008 issued a Sentinel Event—its highest patient advisory—on MR imaging safety, no mandatory MR imaging safety standards exist, nor are they likely to be adopted anytime soon, according to Dr. Shellock, who has been involved in MR imaging safety for 25 years and created and maintains the internationally known website, MRIsafety.com.

    "It would be best if the MR imaging community would implement standards rather than wait for the government to do it, but I'm not confident that will occur," he said. "Liability frequently comes up as a sticking point with these accrediting organizations."

    And because accrediting bodies compete for imaging provider participation, adding new requirements could amount to a disincentive of sorts, according to Gilk, an author of the ACR document. "It's a race to the bottom." Another factor is the intense spotlight on CT and radiation exposure. MR imaging—which does not use ionizing radiation and is therefore not linked to cancer—has avoided similar scrutiny and is even considered a "safe" alternative to CT, keeping it under the radar for regulation, Gilk said.

    Radiologists are Liable

    Despite the lack of mandatory standards, radiologists are responsible for MR imaging-related accidents that occur under their purview—even if the radiologist is offsite at the time. "Sometimes radiologists are alarmed to learn that whoever signs the report is considered the supervising physician, and even if he or she is not physically present, legally it's a very clean line," Gilk said. "Radiologists need to be more directly involved with not only creating safety protocol but also with making sure guidelines are properly implemented, because ultimately, the responsibility rests with them."

    Radiologists need to be involved in making the magnetic room as safe as possible, which can involve anything from making basic architectural changes and installing metal detectors to screening for ferromagnetic objects and training staff on MR imaging safety protocol.

    Such safeguards will become critical as magnet strength increases and healthcare revenues decrease, Gilk said.

    "Clinically, new applications are being unveiled and we've just scratched the surface of what MR can do," Gilk said. "In fact, there is an increasing use of MR in the high-acuity area and emergency rooms. As the number of studies increase, so does the potential for accidents."

    Fortunately, most accidents are preventable. "It's simply a matter of following current guidelines and putting the proper procedures and protocols in place," Dr. Shellock said. Concurred Dr. Kanal: "The extreme majority of MR safety incidents that occur today are entirely avoidable."

    Adherence to MR imaging safety measures comes down to what Gilk calls "enlightened self-interest" on the part of radiologists. "By protecting their patients, technologists and allied personal, radiologists are ultimately protecting themselves," he said.

    Guidelines Can Prevent MR Imaging Accidents

    The following links offer MR imaging safety guidelines:

    • MR imaging safety resource including a comprehensive list of thousands of implants and devices as well as MR imaging safety topics (MRIsafety.com)
    • ACR Guidance Document for Safe MR Practice, originally published in 2002, was rewritten and released early in 2007 as the ACR Guidance Document for Safe MR Practices (www.acr.org).
    • The Joint Commission Sentinel Event Alert on MRI safety issues (www.jointcommission.org)
    • Institute for Magnetic Resonance, Safety, Education, and Research (IMRSER) MRI Safety Guidelines (www.imrser.org)
    • MR safety information for patients (www.RadiologyInfo.org)

    Other MR imaging-related safety sites include:

    MR Imaging Safety Products Featured at RSNA 2010

    Along with the latest in cutting-edge MR imaging technology, the Technical Exhibition at RSNA 2010 features the very latest in MR imaging safety products and devices. For more information on the RSNA 2010 Technical Exhibition, click here.

    Thomas Gilk
    Tobias Gilk
    Frank Shellock
    Frank Shellock, Ph.D. The increasing strength of MR magnets and growing number of MR procedures are among the factors contributing to a 310 percent increase in MR imaging-related accidents since 2004. Following MR imaging safety guidelines can prevent most accidents, according to Tobias Gilk and Frank Shellock, Ph.D., who have created MR imaging safety websites.
    MRI Safety Poster
    This poster warning of potential hazards in an MR imaging system room, can be downloaded at imrser.org and MRIsafety.com.
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