Analysis of CT versus US In Diagnosing Pediatric Appendicitis Shows Disparities

While ultrasound (US) is the recommended first line modality to diagnose pediatric appendicitis, the data shows that CT is also commonly used, which exposes the child to radiation, not to mention the additional cost. 

While ultrasound (US) is the recommended first line modality to diagnose pediatric appendicitis, the data shows that CT is also commonly used, which exposes the child to radiation, not to mention the additional cost. 

An in-depth look at data in the U.S. can help radiologists understand the factors associated with increased CT utilization.

“Acute appendicitis is one of the most common abdominal surgical emergencies in children. The use of imaging is a mainstay in diagnosing appendicitis. Because children are more sensitive to CT radiation than adults, it is important to minimize the use of CT when possible,” said Samuel Byrne, a medical student at the University of Arizona, College of Medicine in Phoenix. 

However, Byrne noted that the results are mixed on how CT is being used.  

“The American College of Radiology (ACR) recommends ultrasound as first line in most cases to avoid exposing children to unnecessary radiation. Its use depends on different factors. That was the driving force for this project—to see if certain groups of children were more likely to have CT done.”

Study Looked At Variety of Social Factors 

The study utilizes data from the Nationwide Emergency Department Sample. All 2019 emergency department encounters with a diagnosis code for appendicitis and a CPT code for either abdominal US or CT were assessed. Differential utilization for each modality was evaluated with respect to sex, race, median household income, primary payer, trauma center status, teaching hospital status and hospital region.

In total, 147,254 patients met the criteria for the study. The average age for patients receiving CT was 13.91 versus 10.78 for US. For patients with annual household income below $48,000, 33.39% of received CT versus 16.68% US. For annual household income over $82,000, CT utilization was 20% versus 30.60% US. 

Different types of medical centers offered different results in modality usage:  

• At non-trauma center, 38.28% of patients were exposed to CT versus 18.02% US. 
• At level 1 trauma centers, this was reversed at 7.98% CT and 30.47% CT. 
• At metropolitan non-teaching centers, 40.39% of patients received CT versus 14.61% US. 
• At metropolitan teaching hospitals, this was reversed at 19.55% CT and 27.21% US.
• In nonmetropolitan hospitals, the rates were 53.05% CT and 10.08% US. 

Across the country, CT utilization was greatest in the Midwest (38.46%) followed by the South (31.43%), Northeast (19.48%), and West (17.95%). Parts of the country that used US more were 37.01% in the Northeast, 21.69% in the West, 18.91% in the Midwest, and 18.56% in the South. 

CT is costlier than US for diagnosing pediatric appendicitis, with US offering significant savings. Total emergency department expense was $15,521 for encounters in which CT was ordered compared to $9,708 in which US was ordered.

“I think continuing to research these disparities is important,” Byrne said. “Hopefully these findings can be used to target future interventions for compliance with ACR Appropriateness Criteria.”

Access the poster, “Higher Age, Low Household Income, Non-Teaching Hospital Status, and Midwest Location Predict Increased CT Over Ultrasound Utilization in Children with Appendicitis,” (M5B-SPPD-3) on demand at RSNA.org/MeetingCentral