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Assessing Appendicitis in Teens and Young Adults

Study shows little difference between low-dose and standard-dose CT

Irina Nistor, MD

Irina Nistor, MD

A study comparing low-dose CT scans to standard-dose scans to diagnose suspected appendicitis in teens and young adults showed little difference in diagnostic accuracy between the two groups.

Prompted by concerns about radiation exposure, particularly in young people, a team of South Korean researchers at Seoul National University College of Medicine compared the rates of negative appendectomy (the percentage of appendectomies for which pathology showed no inflammation).

The study, which appeared in the New England Journal of Medicine last April, showed that among 444 patients in the low-dose CT group the negative appendectomy rate was 3.5 percent. Among the 447 patients in the standard CT group, the rate was 3.2 percent, a nonsignificant difference.

While the study confirms the efficacy of using low-dose CT scans in younger patients, an even better dose reduction strategy is to not use CT, says Irina Nistor, MD, pediatric radiology specialist at Scottsdale Medical Imaging Ltd. (SMIL).

“While the emphasis right now is on low-dose CT in the pediatric population, the best thing is to avoid radiation altogether, so we typically start with ultrasound,” Nistor says. “It is not as sensitive as CT, but in most cases we are able to make a diagnosis.”

She says that since January 2011, SMIL has performed 196 pelvic CT scans in patients under 18 to rule out appendicitis and 183 ultrasounds. Of these, 42 patients had an ultrasound, followed by a CT, because the ultrasound was inconclusive; therefore, 141 patients were diagnosed through ultrasound alone. For those who proceed to CT, SMIL uses a two-pronged dose reduction strategy.

“We reduce the dose in two main ways. One is by the actual scanner (calibrated to) a lower dose,” she says. “The other is that we try to limit the area being scanned.” •

Kim Kyuseok, Kim Young Hoon, Kim So Yeon, et al. Low-dose abdominal CT for evaluating
suspected appendicitis. New England Journal of Medicine. 2012;366:1596-1605.