Even with the known radiation risks to children, CT is often being used as the initial diagnostic tool in children suspected of having kidney stones, according to a study published in Pediatrics.

Despite its 96 percent success rate at locating kidney stones, CT delivers ionizing radiation which carries cancer risks in children. In 2013, the American Urological Association developed imaging protocols for children with suspected kidney stones that recommend CT only if initial ultrasound scans are non-diagnostic.

“The Image Gently Alliance also recommends limiting radiation when possible and promotes alternative imaging modalities such as ultrasound for children who need diagnostic imaging,” wrote lead author Gregory E. Tasian, MD, MSc, MSCE, of the Children’s Hospital of Philadelphia, and colleagues.

The research team set out to determine the prevalence of initial CT scans to identify kidney stones in children and to identify regions in the U.S. where CT is predominantly the first imaging step taken.

To do so, Tasian and colleagues collected data of 9,228 children who underwent diagnostic imaging for suspected kidney stones between 2003 and 2011. Using MarketScan, a commercial insurance claims database that includes information from 17,827,229 children from across the county, the authors were able to determine CT prevalence.

Their research found that 63 percent of children underwent initial CT scans and only 24 percent had ultrasounds performed, as safety guidelines suggest.

The proportion of children who underwent CT by state varied from 41 to 79 percent. Regionally, children in East South Central states like Alabama, Kentucky, Mississippi and Tennessee had the highest odds of receiving and initial CT scan compared to children in New England, who had the lowest odds.

Older children, especially adolescents, were nearly nine times more likely to undergo initial CT scans than two- to five-year-olds. Additionally, girls were more likely to have an initial CT scan than boys.

Overall, Tasian and colleagues wrote that the research shows current imaging practices deviate “substantially from recently published guidelines that recommend ultrasound as the initial imaging study.”