Report: MRI trials safe for children except with contrast, sedation
The physical and psychological risks associated with pediatric MRI in a clinical study protocol are no greater for healthy children than risks they face from everyday activities, such as playing soccer or riding in motor vehicles, though the addition of intravenous contrast dye or sedation increases the odds of harm to unacceptable levels, according to a report appearing in IRB: Ethics and Human Research, a journal of The Hastings Center.
The findings in the report, authored by Matthias H. Schmidt, MD, of Dalhousie University in Halifax, Nova Scotia, and colleagues, clarified which kinds of MRI studies meet the minimal-risk standard, which ethics review boards use to determine if a clinical study or trial can proceed.
“We found that while the physical and psychological risks that attend the MRI procedure do not exceed minimal risk, the sedation and contrast enhancement that are sometimes associated with MRI research do, as both exceed the level of risk encountered by typical, healthy children in their everyday experiences,” wrote the authors in the study abstract.
Researchers used a risk analysis that considered the risks from MRI alone, as well as the risks from contrast agents and sedation, comparing them to systematic reviews of the risks from several everyday activities of healthy children.
They found the risk of physical injury from MRI is 17 per 100,000 examinations and the risk of death is 4 per 100 million examinations. This compares favorably with the risk of injury for children under the age of 16 who participate in a variety of sports and recreation activities. The levels of risk ranged from participation in soccer, which results in four injuries per 100,000 hours of play, to ice hockey, which produces 12,730 injuries per 100,000 hours of play. Assuming an MRI exam lasts an hour, the risk of injury associated with MRI falls on the lower end of this range, according to the authors.
The authors also compared the death rates of children undergoing MRIs versus children riding in motor vehicles, which poses the highest risk of mortality to healthy children. The motor vehicle risk ranges from six deaths per 100 million car trips for children ages 14 years and younger to 40 per 100 million for children ages 15 to 19.
"Thus, the risk of death from an MRI examination (four per 100 million) is clearly less than the risk of death from a car trip," wrote the authors. “MRI can therefore meet the minimal-risk standard from the point of view of physical harm.”
As for psychological harm, in studies of children ages 10 to 18 years old who had MRI scans, 12 percent said they felt disturbed by the confined space, 16 percent said they were bothered by the noise and 1.2 percent could not complete their MRI scan due to claustrophobia. But these percentages were lower on average than the percentages of children who report fears associated with anxiety disorders–in one study of children 8 to 13 years of age, for example, 49 percent reported fears associated with subclinical anxiety and 22 percent met the full criteria of an anxiety disorder.
When an MRI examination calls for the injection of contrast, there is the risk of allergic reactions, such as fever, headache and anaphylaxis. The authors compared these risks with the risk of allergic reactions following routine vaccinations and while the risk of local and minor systemic reactions from MRI contrast dyes (4 percent to 6 percent) is comparable to the risk of minor reactions from routine vaccinations, the risk of anaphylaxis from MRI contrast dyes (7.5 per 100,000 doses) is higher than the risk of anaphylaxis from vaccinations. This led the authors to conclude that MRI with contrast enhancement doesn’t meet the minimal-risk standard.
They also concluded that the risk from sedation in MRI protocols, which includes gastrointestinal complaints (18 percent to 37 percent) and motor imbalance (66 percent to 85 percent), does not meet the minimal-risk standard, based on the risks posed by sedating medications such as over-the-counter cold medicines.
The authors wrote that research ethics review boards should consider all the risks involved and may wish to use the report as a “springboard for the their deliberations” when evaluating protocols involving children and MRI.
The findings in the report, authored by Matthias H. Schmidt, MD, of Dalhousie University in Halifax, Nova Scotia, and colleagues, clarified which kinds of MRI studies meet the minimal-risk standard, which ethics review boards use to determine if a clinical study or trial can proceed.
“We found that while the physical and psychological risks that attend the MRI procedure do not exceed minimal risk, the sedation and contrast enhancement that are sometimes associated with MRI research do, as both exceed the level of risk encountered by typical, healthy children in their everyday experiences,” wrote the authors in the study abstract.
Researchers used a risk analysis that considered the risks from MRI alone, as well as the risks from contrast agents and sedation, comparing them to systematic reviews of the risks from several everyday activities of healthy children.
They found the risk of physical injury from MRI is 17 per 100,000 examinations and the risk of death is 4 per 100 million examinations. This compares favorably with the risk of injury for children under the age of 16 who participate in a variety of sports and recreation activities. The levels of risk ranged from participation in soccer, which results in four injuries per 100,000 hours of play, to ice hockey, which produces 12,730 injuries per 100,000 hours of play. Assuming an MRI exam lasts an hour, the risk of injury associated with MRI falls on the lower end of this range, according to the authors.
The authors also compared the death rates of children undergoing MRIs versus children riding in motor vehicles, which poses the highest risk of mortality to healthy children. The motor vehicle risk ranges from six deaths per 100 million car trips for children ages 14 years and younger to 40 per 100 million for children ages 15 to 19.
"Thus, the risk of death from an MRI examination (four per 100 million) is clearly less than the risk of death from a car trip," wrote the authors. “MRI can therefore meet the minimal-risk standard from the point of view of physical harm.”
As for psychological harm, in studies of children ages 10 to 18 years old who had MRI scans, 12 percent said they felt disturbed by the confined space, 16 percent said they were bothered by the noise and 1.2 percent could not complete their MRI scan due to claustrophobia. But these percentages were lower on average than the percentages of children who report fears associated with anxiety disorders–in one study of children 8 to 13 years of age, for example, 49 percent reported fears associated with subclinical anxiety and 22 percent met the full criteria of an anxiety disorder.
When an MRI examination calls for the injection of contrast, there is the risk of allergic reactions, such as fever, headache and anaphylaxis. The authors compared these risks with the risk of allergic reactions following routine vaccinations and while the risk of local and minor systemic reactions from MRI contrast dyes (4 percent to 6 percent) is comparable to the risk of minor reactions from routine vaccinations, the risk of anaphylaxis from MRI contrast dyes (7.5 per 100,000 doses) is higher than the risk of anaphylaxis from vaccinations. This led the authors to conclude that MRI with contrast enhancement doesn’t meet the minimal-risk standard.
They also concluded that the risk from sedation in MRI protocols, which includes gastrointestinal complaints (18 percent to 37 percent) and motor imbalance (66 percent to 85 percent), does not meet the minimal-risk standard, based on the risks posed by sedating medications such as over-the-counter cold medicines.
The authors wrote that research ethics review boards should consider all the risks involved and may wish to use the report as a “springboard for the their deliberations” when evaluating protocols involving children and MRI.
Evan Godt, Writer
Evan joined TriMed in 2011, writing primarily for Health Imaging. Prior to diving into medical journalism, Evan worked for the Nine Network of Public Media in St. Louis. He also has worked in public relations and education. Evan studied journalism at the University of Missouri, with an emphasis on broadcast media.