The Impact of a Preauthorization Policy on the After-hours Utilization of Emergency Department Computed Tomography Imaging

Published:February 29, 2016DOI:

      Rationale and Objectives

      We evaluated the effects of a streamlined emergency department (ED) policy for CT ordering, pre- and postimplementation, on the completed imaging study rates of all after-hours computed tomography (CT) studies. The study hypothesis was that a streamlined CT ordering process would increase the utilization rates of ED CT.

      Materials and Methods

      A prospective cohort study was used to estimate the effect of enhancing a preauthorization policy for after-hours CT studies requested through the ED, performed between January 1 and June 30, 2013, and the postimplementation period, performed between January 1 and June 30, 2014. Inclusion criteria were all CT chest, CT abdomen/pelvis, musculoskeletal, neurological, and neuroangiographic examinations performed by ED physicians on adult patients. Pre- and postintervention examination imaging study rates were compared.


      The period following implementation of the preauthorization policy was associated with a statistically significant increase in utilization for most subtypes of CT examinations (CT chest, CT abdomen/pelvis, and musculoskeletal CT studies), with the exception of neurological examinations, which showed a significant decrease.


      This study demonstrates a trend toward increased utilization of CT resources after implementation of an ED preauthorization policy with most study types showing significantly increased utilization. In the case of neurological examinations, a potential “substitution effect” was observed, whereby the rates of neuroangiographic studies showed a marked increase, offsetting the decrease in general neurological examinations performed. Departments considering implementation of preauthorization policies should weigh carefully the benefits of ED workflow efficiencies against the potential harms of increased CT use.

      Key Words

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