Pediatric CT Techniques Scan Hearts in a Fraction of the Dose

AuntMinnie | New techniques for coronary CT angiography (CTA) — particularly high-pitch
scanning — are slashing radiation dose levels to provide safer scans for children without the need for sedation, according to a study presented at last week’s Society of Cardiovascular Computed Tomography (SCCT) meeting in Denver.

Among several ultralow-dose techniques used by the study team from Minneapolis Heart Institute in Minneapolis, high-pitch dual-source CTA delivered excellent image quality for a fraction of a millisievert of radiation when heart rates could be reduced sufficiently, they said.

Traditionally, pediatric patients who require coronary artery imaging have undergone cardiac catheterization, an invasive procedure with a significant radiation dose that also requires sedation for all age groups, said pediatric cardiologist Dr. B. Kelly Han in an interview with.High-pitch scan showing anomalous right coronary artery in a 17-year-old patient. Image courtesy of Dr. B. Kelly Han.

“Children are more sensitive to radiation than adults, and they have a longer time for any radiation damage to take effect,” Han said. Those with congenital heart disease typically receive many scans and a lot of radiation.

“One article estimates 20 mSv by the time they reach adolescence,” mostly from catheterization procedures (approximately 3 mSv each), in addition to chest x-rays and other diagnostic studies, Han said. “Rather than look at the risk for each procedure, we’re starting to look at cumulative risk over the patient’s lifetime.”

Newer CT scanners deliver far less radiation than previous models. However, high heart rates have been a barrier to the use of coronary CTA in children, she said. MRI is also an option, “but for small babies and for distal coronary vessels it’s really not good enough yet to give us that information.”

If a child has a very low likelihood of coronary artery pathology and he or she is older, the team will usually opt for MRI — reserving CT for patients for whom MRI was not diagnostic, Han said. However, with MRI of the coronary arteries, “image quality is pretty much inversely related to age,” she said. “You can see the origins pretty well but usually not the distal vessels.”


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