The slight risk of cancer from exposure to radiation during high-tech imaging procedures has prompted Children’s Hospitals and Clinics of Minnesota to limit the scans for children who show up with abdominal pains.

Testing a new decisionmaking system, Children’s reduced the rate of CT scans by 25 percent from 2011 to the start of 2013 in its Minneapolis and St. Paul emergency rooms for children with abdominal pains — without an increase in misdiagnosis or complications, according to data the hospital system released last week.

Overuse of CT scans began for well-intended reasons over the past decade, because doctors didn’t want to miss cases of appendicitis in children that could later rupture and cause severe and disabling complications, said Dr. Anupam Kharbanda, Children’s director of emergency services research. Trouble is, only one in 100 children who enter an ER with abdominal pain actually has an inflamed appendix that must be removed before it bursts.

The new decisionmaking system warns doctors when they enter computer orders for CT scans based on symptoms that suggest a low risk of appendicitis, Kharbanda said. “That alert basically says, ‘Stop, think about what you are going to do.’ ”

Children at low risk for appendicitis generally have pains because of viral infections or constipation, and can be diagnosed without imaging. Children at medium risk are encouraged to receive an ultrasound, which is less expensive and safer than a CT scan.

Minnesota’s health care system has been a leader, nationally, in the reduction of questionable CT scans — starting in 2006 when the state’s largest insurers and clinic groups agreed on a red-yellow-green ranking system that assessed the risk vs. reward of high-tech imaging procedures for adults.

Growth in imaging procedures slowed from 7 percent annually to 1 percent in subsequent years, saving an estimated $234 million. Based on estimates that 1 percent to 2 percent of cancers are related to radiation exposure from imaging procedures, the collaboration prevented an estimated 96 cancer-related deaths in Minnesota between 2007 and 2012, according to the Bloomington-based Institute for Clinical Systems Improvement.

Kharbanda said reducing radiation exposure is particularly important in children, because there is evidence that their exposure-related cancer risks are greater.

“Not when they’re 5,” he said, “but like in their 40s and 50s.”

Kharbanda published two studies verifying that the medical criteria in the new Children’s tool identify children most likely to benefit from diagnostic imaging.

Now Children’s has received a research grant of $3.1 million from the National Institutes of Health to test the tool’s effectiveness in 14 community hospitals in Minnesota and California.

Changing practices in his own pediatric hospital was a good step, but Kharbanda said the challenge is to improve decisionmaking among doctors in community hospitals that see most of the children with abdominal pain.

“It’s guidance,” he said. “It does not dictate care, and that’s one of the major criticisms that we addressed when we designed this is that clinicians did not want to be told what to do.”

Jeremy Olson • 612-673-7744