Medical Design Briefs - April 2023 - 8

MRI Safety Testing
In its testing facility in New Brighton, MN, TÜV SÜD is able to expose implants and other medical devices to conditions experienced during magnetic resonance imaging.
(Credit: TÜV SÜD)
compromise the operation of these potentially
life-saving devices and place the
health and safety of patients at risk. If
medical devices or implants are located
near an MRI system, there are risks associated
with that proximity. For example,
the electromagnetic fields of MRI can interfere
with the function of pacemakers
or middle ear implants due to the magnetic
field generated. Nonactive medical
implants such as artificial joints made of
metal can interact with the MRI due to
the electromagnetic radiation. This interaction
may result in injury or health risks.
Accordingly, implantable medical devices
must be thoroughly evaluated and
tested to ascertain the possible impact of
such hazards and the degree of potential
risk in the MRI environment. Medical
device manufacturers have a duty to reliably
test their products for risks associated
with use in an MRI environment.
During so-called MRI safety testing,
OEMs receive recommendations for the
safety and usability of their products in
connection with MRI diagnostics and, in
addition, essential information for their
labeling even before market entry.
Implantable Medical Devices in the
Regulatory Environment
Regulators in major jurisdictions
around the world are actively working to
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address the potential risks to patients
with implantable medical devices in the
MRI environment. For example, the
U.S. Food and Drug Administration
(FDA) requires that device manufacturers
submit to the agency an application
for premarket review for any new or substantially
modified medical device they
wish to place on the market. To address
the specific safety challenges associated
with implantable medical devices in the
MR environment, the agency issued in
2021 an updated version of its guidance
document on the " Testing and Labelling
of Medical Devices for Safety in the Magnetic
Resonance (MR) Environment "
(Docket Number FDA-2019-D-2837).
And in Europe, the EU's Medical Device
Regulation (EU 2017/745, also known
as the MDR) sets forth rules applicable
to all medical devices sold or marketed
in EU member states.
Meeting regulatory requirements applicable
to active and nonactive implantable
medical devices generally requires
that device manufacturers demonstrate
compliance with the specifications of
one or more of the industry-accepted
consensus standards. Currently, these
are ASTM F 2052, 2213, 2182, 2119, 2503
as well as ISO/TS 10974. Each of these
standards is recognized by the U.S. FDA
as a consensus standard for use with
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medical device testing and labeling.
While none of the above standards have
yet to be published as harmonized standards
under the EU's MDR, these standards
do represent current state-of-theart
practices and should be considered
in assessing an implantable device for
compliance with the MDR requirements.
Labeling for MR safety
The end goal of any safety testing conducted
on implantable medical devices
is to determine the safety of that device
in an MR environment. A safety framework
is provided by the widely accepted
standard ASTM F2503, " Standard Practice
for Marking Medical Devices and
Other Items for Safety in the Magnetic
Resonance Environment. " It is applicable
to implantable devices sold or marketed
in both the United States and the
EU. Under ASTM F2503, implantable
devices are categorized in one of the following
three categories:
* MR Safe. This can be applied without
testing to any implantable device that
poses no known hazards in any MRI
environment, including those that do
not include any magnetic, conductive,
or metallic materials.
* MR Unsafe. This is the default category
initially applied to all active implantable
medical devices before testing.
Medical Design Briefs, April 2023

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Medical Design Briefs - April 2023

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