May 19, 2008

MRI SAFETY CONCERNS:  Recently we had the chance to review some safety issues relating to the use of MRI in pediatric patients.  Further, the JCAHO released a sentinel event update on MRI safety in February 2008.  In light of the current interest and the potential risk involved, I asked Elizabeth Ey, MD, to provide an update for the professional staff as well as others who refer to our medical imaging division.  Her thoughtful review of the problem is presented for your information.

Recently, the JCAHO published a sentinel event alert regarding safety concerns in MRI.  The alert reported numerous serious injuries and even several deaths, which have occurred in the MRI environment.  The medical imaging department at Dayton Children's has had in effect for several years an MR Safe Practice Policy, which follows the guidelines established by the American College of Radiology.  Strict adherence to the policy prevents these MR related injuries from occurring.  It is important to review the safety concerns for referring physicians and health care providers.

The majority of the reported injuries and deaths are related to the magnetic force exerted on ferromagnet objects (missile effect), magnetic effect on metal implants and foreign bodies (heating and burns) and magnetic effect on electrical or mechanical implants (electric or mechanical malfunction of implants).  It is critical to remember that the magnetic field is very strong and is always on, even at night when the MRI is not being used.  The MR scan room is always carefully attended or locked.  Only people who have been screened for safety concerns are allowed in the scan room and only under the approval of the MR technologist in attendance.

The missile effect refers to a metal object being propelled through the air by magnetic force and smashing into the magnet and anything in its path.  Oxygen cylinders, IV pumps and wheel chairs are examples of ferromagnetic objects, which have caused significant injury and death to patients and staff in the MRI environment.  Any object not certified to be MR safe is strictly prohibited in the MR scan room.  Heating and serious skin burns can occur from the magnetic effect on wires, cables and tattoos on the skin.  Remember the physics of inducing an electrical current through a wire loop using a magnet?  Electronic equipment such as pacemakers, implanted infusion pumps and defibrillators will malfunction in the MR environment.  Some valves for CSF shunts are programmed using a small magnet.  These will need to be reset after the MR exam in order to resume correct function.

The MR technologist is responsible for screening anyone wishing to enter the MR scan room and the high magnet field environment.  The questionnaire is lengthy but vitally important to prevent injuries and ensure safety.  If there is any doubt about the safety of an implant or device in the MR environment, the study will be postponed until it is determined safe to proceed or an alternate imaging study will be performed.  For further information please refer to the MR Safe Practice Policy or contact Elizabeth H. Ey, MD, in the medical imaging department at 937-641-3204.