title: The Impact of a Preauthorization Policy on the After-hours Utilization of Emergency Department Computed Tomography Imaging.
abstract: OBJECTIVE
  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.
  
  
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Medical Imaging, University of Toronto, 263 McCaul Street, 4th Floor, Toronto, ON M5T1W7, Canada; Institute of Health Policy, Management and Evaluation, University of Toronto, 155 College Street, 4th Floor, Toronto, ON M5T3M6, Canada. Electronic address: kirsteen.burton@utoronto.ca.
authors.forename: Kirsteen R
authors.initials: KR
authors.lastname: Burton
authors.affiliation: Department of Medical Imaging, University of Toronto, 263 McCaul Street, 4th Floor, Toronto, ON M5T1W7, Canada.
authors.forename: Raymond L
authors.initials: RL
authors.lastname: Lawlor
authors.affiliation: Department of Medical Imaging, London Health Sciences Centre, Victoria Hospital, University of Western Ontario, London, ON, Canada.
authors.forename: Deljit
authors.initials: D
authors.lastname: Dhanoa
mesh_terms: D000328:Adult; D039602:After-Hours Care / Q000458:organization & administration*; D000792:Angiography / Q000706:statistics & numerical data; D015331:Cohort Studies; D004636:Emergency Service, Hospital / Q000458:organization & administration*; D006801:Humans; D050316:Medical Order Entry Systems / Q000458:organization & administration*; D009141:Musculoskeletal System / Q000000981:diagnostic imaging; D009485:Neuroradiography / Q000706:statistics & numerical data; D016134:Organizational Policy; D010388:Pelvis / Q000000981:diagnostic imaging; D011446:Prospective Studies; D011860:Radiography, Abdominal / Q000706:statistics & numerical data; D013902:Radiography, Thoracic / Q000706:statistics & numerical data; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*
keywords: Tomography; emergency service; hospital; x-ray computed