Simple MRIs Safe for Children, Study Says10/07/11
FRIDAY, Oct. 7 (HealthDay News) -- Exposing children to MRIs
during pediatric clinical trials is not unduly risky to their
well-being as long as sedation and injectable dyes aren't used, new
Canadian research concludes.
The study finds that MRIs, when used without additional
intravenous contrast dyes or sedation, pose no greater physical or
psychological harm to healthy children than routine activities such
as playing sports or riding in a car.
However, injectable contrast dyes, which are used to improve
scan resolution, may pose an unreasonable allergic-reaction risk
that is greater than that posed by, for example, routine
vaccinations, the researchers found.
Similarly, using sedation during imaging sessions appears to
raise the risk for side effects, such as gastrointestinal issues
and motor imbalance, to a level considered unsafe for children.
Lead author Dr. Matthias H. Schmidt, an associate professor in
the department of radiology at Dalhousie University in Halifax,
Nova Scotia, reported his team's findings in the September/October
IRB: Ethics & Human Research.
Schmidt and his colleagues noted that research ethics review
boards have long struggled with the question of MRI safety in the
context of pediatric research.
The team thus set out to establish so-called "minimal-risk
standards" for pediatric imaging exposure safety by analyzing a
range of information, including MRI safety data collected by the
U.S. Food and Drug Administration's "Manufacturer and User Facility
The bottom-line: Ice hockey and soccer pose as much, if not
more, risk for physical injury to children as MRIs.
While the risk for physical injury to children posed by an
hour-long MRI is 17 for every 100,000 imagings, the risk for injury
is as high as 12,730 for every 100,000 hours a child under the age
of 16 plays ice hockey, the study found.
Similarly, the risk of dying from an MRI scan (four for every
100 million scans) is much less than the risk of dying in a car
accident (six for every 100 million car trips for children 14 and
under and 40 per hundred million rides for teens 15 to 19), the
Also, the risk of suffering psychological hardship, such as
claustrophobia and/or noise disturbances, appeared to be greater
among children struggling with anxiety disorders than it did among
those exposed to an MRI.
But the MRI-associated chance that a child would develop either
gastrointestinal issues (an 18 to 37 percent risk) or motor
imbalance (a 66 to 85 percent risk) was deemed to be above
reasonable safety standards.
And use of a contrast dye appeared to unduly raise the risk for
developing a fever, headache or an anaphylaxis reaction.
The team therefore concluded that while MRIs themselves are safe
for children in a clinical trial setting, the use of contrast dyes
and/or sedation is not, and should be avoided.
"We urge researchers and [research ethics review boards] to collaborate in the ongoing effort to minimize the risk of harm and discomfort associated with pediatric MRI research," the authors said in a news release from the journal publisher.
Meanwhile, Joy Hirsch, a professor of functional neuroradiology,
neuroscience and psychology at Columbia University Medical Center
in New York City, and a director of the CU's Functional MRI
Laboratory, expressed little surprise with the Canadian team's
"The FDA has characterized MRI as a minimal risk procedure," she noted. "And this is not something that involves radiation. So, this is not an invasive procedure and there is no incremental risk over time."
"But these are incredibly important questions that are being looked at," Hirsch added. "So you do want to have a clear risk-benefit analysis, and you do want to be careful. So, I would say that if the data suggests that contrast dyes and sedation -- both of which are foreign injects into the body -- are a problem, then we have to listen to the data."
For more on MRIs, visit the
American College of Radiology.
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