Related Experiment Video
Updated: Mar 24, 2026

Signal Acquisition, Score Interpretation, and Economics of a Non-Invasive Point-of-Care Test for Coronary Artery Disease
Published on: August 9, 2024
The Impact of a Preauthorization Policy on the After-hours Utilization of Emergency Department Computed Tomography
Kirsteen R Burton1, Raymond L Lawlor2, Deljit Dhanoa3
1Department 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.
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.
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.
Related Concept Videos
Computed Tomography
The technique was invented in the 1970s and is based on the principle that as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates...
Imaging Studies III: Computed Tomography
Imaging Studies I: CT and MRI
Description of the Procedures
Computed Tomography (CT) scan:
Computed Tomography (CT) scans use X-ray technology to generate detailed images of bones, organs, and tissues. During the scan, the patient lies on a moving table...
Imaging Studies for Cardiovascular System V: CT
Radiological Investigation I: X-ray and CT
Radiological Investigation III: Pulmonary Angiogram and PET Scan
Pulmonary Angiogram
A Pulmonary Angiogram is an invasive procedure involving injecting a contrast medium through a catheter threaded into the pulmonary artery or the right side of the heart to visualize the pulmonary vasculature. Computed Tomography (CT) scans have mainly replaced this...

