Suggestions included improvements in the training and education required for technologists, appropriate use of ferromagnetic detectors, and up-to-date, reliable labeling information on implanted devices. But a major sticking point is whether guidelines are sufficient, or more stringent regulation is needed.
MRI use has become more prevalent among healthcare providers as the modality is increasingly used as a substitute for CT in some clinical applications to reduce radiation exposure to patients. Approximately 30.2 million MRI procedures were performed in the U.S. last year, according to market research firm IMV Medical Information Division, representing growth of slightly less than 90% from 2000 to 2009.
At the same time, however, there has been a 523% increase in MRI accidents reported to the FDA's Manufacturer and User Facility Device Experience (MAUDE) database over the same time period.
The vast difference illustrates "the degree to which we have failed to manage safety with the growth of MR," said Tobias Gilk, president and MRI safety director at Mednovus and senior vice president at design and architecture firm Rad-Planning.
Thermal-related issues were the most common adverse MRI events reported to MAUDE between January 2006 and December 2010. Patients experienced second- and third-degree burns and blisters because they were not padded appropriately or they came into contact with the MRI bore or an imaging coil during the scan.
Other MRI accidents were attributed to inadequate or missing safety labeling, or situations where a device was not MR compatible but a scan was performed anyway. Patients also reported hearing damage or ringing in the ears after an exam because no ear protection was given or the protection was faulty.
Projectile incidents were less frequent but still caused serious damage when staff brought large or small ferrous objects into the MRI room or patients had metal objects. Patients also experienced shocks or nerve stimulation during MRI scans. About half of the MAUDE reports suggest the incidents in these cases were due to a medical accessory or implanted device.
"One loss of life or limb can ruin your whole afternoon," quipped Dr. Emanuel Kanal, director of MR services and professor of radiology and neuroradiology at the University of Pittsburgh Medical Center. "Whether it be perceived or real, these adverse events are 100% preventable. The problem is that time is up, and we are not doing a good job of regulating ourselves. We are not even close to zero serious events."
To help eliminate avoidable accidents, Vera Kimbrell, an MRI technologist for more than 20 years and a member of the Section for Magnetic Resonance Technologists (SMRT) of the International Society for Magnetic Resonance in Medicine (ISMRM), said her organization supports the American College of Radiology's MRI safety guidelines, and advocates that manufacturers of implanted devices provide better labeling and instructions.
"We also have a plea to the manufacturers and vendors of [MRI] equipment to give us better guidelines and better safety information," Kimbrell said. "We also request that the FDA focus more on education; not only education for professionals, but education of the public, and education for anyone who is going to use an MRI scanner."
Anne Marie Sawyer, manager of MR whole-body research systems at Stanford University School of Medicine, voiced strong concern about the lack of required, ongoing education for MRI technologists.
"There ... is a lack of focus, in my opinion, on patient burns," she said. "Is it radiofrequency? Is it the time-varying gradient magnetic fields? How do we protect and prevent these things from happening so we can protect our patients? We, as technologists, need to understand how these things happen in each and every situation. If we don't understand, then we cannot develop the critical eye we so desperately need to protect our patients."
Over the past 18 months, imaging services firm RadNet performed 786,000 MRI examinations; during this time, adverse MRI events included 10 burns, four shocks, two patients with hearing issues, four metal incidents, and one issue with a patient's pacemaker. There were no projectile accidents. The most common MRI problem was adverse reactions to contrast agents, of which 57 cases were reported.
Dr. John Crues III, medical director at RadNet, told the workshop that all of the company's MRI personnel are screened prior to being hired, and all patients and non-MRI staff must complete screening forms, which are reviewed by MR technologists. Security personnel also are checked for ferrous and magnetic objects before entering the magnet room, and all restraints in the MRI suite must be made of plastic.
"Guidelines have a lot of value when supported by objective evidence, but we have little cost-efficacy analysis of any of the potential guidelines that have been recommended in the community," Crues said. "We do need more cost-efficacy analysis."
Since 2004, both the American College of Radiology and the Joint Commission have updated their recommended MRI safety guidelines, but the documents have not reversed the growth of MRI accidents. Gilk believes that the lack of a positive effect is because the guidelines are only recommendations.
"There is not a single regulatory, accreditation, or state licensure body that has physical safety requirements at the point of care for MRI safety that would prevent the 2001 Colombini accident from occurring or the thousands of others that occur," Gilk said. "We need objective, measurable, MR safety standards."
To eliminate projectile accidents, workshop attendees said they support the use of ferromagnetic detectors as an adjunct to screening for metal objects in the MRI room. There was, however, no definitive consensus on whether the FDA should regulate the devices.
Gilk believes that ferromagnetic detection technology can be an "abysmal failure, when facilities buy it thinking that it is their safety net ... in lieu of a competent, qualified, attentive technologist." The detectors are better utilized to learn how poorly patients conform to screening instructions, so technologists can refine their own screening protocols and determine how potentially hazardous objects enter the magnet room.
"Those folks really see benefits from the technology," Gilk noted.
Keith Kopp, president of ferromagnetic detection firm Kopp Development, concurred that the devices should be used as a supplement rather than a definitive screening tool.
"You never want to automate this [process] because there are so many other things you need to screen for and make judgments on," Kopp said. "This is just another tool in the toolkit, and it has to be used that way."
The issue of implanted devices is even more complex for MRI technologists and physicians, especially in emergency cases.
The uncertainty that a patient might have a pacing system implanted -- and the lack of readily available MR safety information about an implanted device -- can cause great consternation prior to an MRI scan, Kanal said.
"Every technologist who deals with this area recognizes the tremendous amount of time that is spent or wasted trying to get information about an implant, and then come to find out no one has ever formally tested it," he said. "Even knowing that it has not been tested helps us with a risk-benefit decision."
Kanal advocated that manufacturers maintain up-to-date information on all of their implantable devices. "That should be done with every manufacturer and every implant or attached device," he said. "It should be mandated that it be put on a website that will [have] all the current information."
In addition, the FDA should mandate MRI safety testing and reporting of test results for all devices that are designed, marketed, and distributed for implantation in or attachment to the body, whether it be an insulin pump or a pacing system, according to Kanal. If the FDA has not tested a particular product or device, that information should be posted as well.
When the FDA approved Medtronic's Revo MRI SureScan pacemaker in February, the company began an online training program for both cardiologists and radiologists. "We were reluctant to take on the training requirements because our feeling at the time was that no other manufacturers have been required to do that," said Jeff Burrows, Medtronic's MRI program director.
Six months later, Burrows said the company received "very positive feedback" on the availability of the training.
"Our feeling, at this point, is that we support MR conditions training for life-sustaining devices," he said. "There are some additional requirements related to scanning a pacing system that are above and beyond just the simple magnet management, such as managing the device before and after the scan. We are in full support of doing this."
Medtronic also distributes patient identification cards with information about a patient's implanted device, but the card does not say whether the patient can be given an MRI scan. "That [decision] was after much discussion with FDA on the final labeling," Burrows said. "We decided to make sure that we said whether it is a complete [implanted] system, but nothing more. It is up to the technologist and physician to check for additional information."
The FDA will continue to take public comments on MRI safety until November 22.
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