National Trends in Use of Computed Tomography in the Emergency Department

      Study objective

      The role of computed tomography (CT) in acute illnesses has increased substantially in recent years; however, little is known about how CT use in the emergency department (ED) has changed over time.


      A retrospective study was performed with the 1996 to 2007 National Hospital Ambulatory Medical Care Survey, a large nationwide survey of ED services. We assessed changes during this period in CT use during an ED visit, CT use for specific ED presenting complaints, and disposition after CT use. Main outcomes were presented as adjusted risk ratios (RRs).


      Data from 368,680 patient visits during the 12-year period yielded results for an estimated 1.29 billion weighted ED encounters, among which an estimated 97.1 million (7.5%) patients received at least one CT. Overall, CT use during ED visits increased 330%, from 3.2% of encounters (95% confidence interval [CI] 2.9% to 3.6%) in 1996 to 13.9% (95% CI 12.8% to 14.9%) in 2007. Among the 20 most common complaints presenting to the ED, there was universal increase in CT use. Rates of growth were highest for abdominal pain (adjusted RR comparing 2007 to 1996=9.97; 95% CI 7.47 to 12.02), flank pain (adjusted RR 9.24; 95% CI 6.22 to 11.51), chest pain (adjusted RR 5.54; 95% CI 3.75 to 7.53), and shortness of breath (adjusted RR 5.28; 95% CI 2.76 to 8.34). In multivariable modeling, the likelihood of admission or transfer after a CT scan decreased over the years but has leveled off more recently (adjusted RR comparing admission or transfer after CT in 2007 to 1996=0.42; 95% CI 0.32 to 0.55).


      CT use in the ED has increased significantly in recent years across a broad range of presenting complaints. The increase has been associated with a decline in admissions or transfers after CT use, although this effect has stabilized more recently.
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      Linked Article

      • The Truth About the Increase in Computed Tomography Utilization
        Annals of Emergency MedicineVol. 59Issue 5
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          The recent study by Kocher et al1 is one of several documenting a striking increase in the use of computed tomography (CT) in emergency department (ED) patients during the past decade. Their study analyzes CT utilization by the patient's presenting complaint and finds particularly eye-popping growth in CT utilization for certain common clinical presentations: abdominal pain, flank pain, chest pain, and shortness of breath. CT utilization rates increased 10 times or more from 1996 to 2007.
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