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
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.
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