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Child-proof: Brain mapping safer for children than previously thought, Hopkins study shows

October 09, 2006

Dispelling a stubborn myth, researchers at Johns Hopkins have shown that children with strokes, brain tumors and other cerebrovascular diseases can safely undergo a potentially life-saving brain-mapping test that many doctors have long shunned over concerns for side effects. Analysis of 241 cerebral angiograms performed on 205 children at the Johns Hopkins Children's Center between 1999 and 2006 showed that not a single patient suffered complications during or immediately following the procedure.

Results of the analysis, believed to be the first study in more than 25 years to look at the safety of cerebral angiographies in children, are reported in the October issue of Stroke.

Performed by threading a catheter into the patient's groin, through the abdomen and the chest and upward into the arteries of the neck, cerebral angiography is the most accurate brain-vessel imaging technique available and a critical diagnostic and treatment tool, says Lori Jordan, M.D., a pediatric neurologist at the Children's Center and a co-author of the report.

"The assumption that angiographies in children are more dangerous than in adults has persisted over the years-mostly due to lack of evidence," says study senior author Philippe Gailloud, M.D., an interventional neuroradiologist at Johns Hopkins. "When we ask parents to sign consent for an angiography, their first question is how safe it is, and up until now, we didn't have any hard data to show them. Given the very low risk of complications we see, pediatric neurologists should not hesitate to order the procedure, and we can say to them that we have research showing this procedure is indeed very safe in children."

The most dreaded complication of the procedure is accidental damage to a blood vessel that can cause a stroke.

"This is an invasive procedure, so obviously physicians must be careful in determining how appropriate it is in a child, but as doctors, we should keep in mind that we shouldn't deny the potentially crucial assistance of an invasive procedure because of overblown assumptions of danger," Gailloud says.

Delayed diagnosis and treatment are also dangerous, and sometimes fatal, Gailloud notes, particularly in cases of ischemic stroke caused by a clot or lack of blood supply to the brain vessels; hemorrhagic stroke, caused by a ruptured brain vessel that bleeds into the brain; and brain tumors and certain types of malformations of blood vessels in the brain, which also may rupture and bleed. "An angiogram is absolutely critical when a child has suffered an unexplained bleeding in the brain," he adds.

Among those studied, a single death occurred three hours after an angiogram and was attributed to bleeding in the brain that the patient had suffered before admission to the hospital, the Hopkins team said. None of the patients developed blood clots in the groin, a common and potentially dangerous complication of puncturing the femoral artery, and none reported leg pain, difficulty walking or limping during an average follow-up of 28 months.

While most angiograms are diagnostic, they can also be used to treat spinal and brain malformations endovascularly-or from within the blood vessel-and thus offer a less-invasive alternative to neurosurgery for certain conditions.

In some cases, diagnosis is possible with noninvasive imaging tests such as CT scans or magnetic resonance imaging (MRI), but these tests can give false-positive or false-negative results, meaning they would diagnose a problem where there is none or fail to detect one.

"Unfortunately, we don't know how often noninvasive tests are missing or misdiagnosing something," Jordan says. "We do know that angiography is clear."

Compared to doing the test in adults, the procedure in children usually takes less time because they have fewer other medical conditions that might cause complications, Jordan adds. In addition, technological advances over the past 20 years, such as smaller, softer catheters and guided imagery also make angiograms in children safer.

Each year, about 3,200 children suffer a stroke, up to half of whom develop permanent cognitive or motor disabilities. About one-third of them will have another stroke, and up to one-fifth of affected children will die. Risk factors for stroke in children include heart disease, sickle-cell anemia, some blood-clotting disorders, vascular malformations, and viral infections, such as varicella, HIV and others.

Johns Hopkins Medical Institutions