Introduction: Computed tomography (CT) is often ordered for patients in whom the diagnosis of acute pancrea-titis (AP) has already been established via elevated lipase levels and typical abdominal pain. We investigated whether early CT imaging performed in the ED altered the diagnosis or management. Methods: A retrospective chart review was performed on patients presenting to a large, academic ED between the years 2013-2015 with AP who received CT imaging. Relevant history, laboratory, imaging data, and hospital course were abstracted from the medical record and analyzed by three independent reviewers, with 100% agree-ment among reviewers on 30 randomly selected cases. The primary outcome was whether the CT led to a change in diagnosis or management above and beyond the ultrasound. Univariate and multivariate analyses were per -formed to determine association between predictor variables and outcomes. Results: The electronic health record query yielded 458 patients. Of those, 174 met the American College of Gas-troenterology criteria for AP and were included in the study. 145 patients (83%) had abdominal CT during their hospital course, 125 (86%) of which were performed in the ED. Of these 145 patients, 57 (39%) had imaging ev-idence of AP. 107 patients had abdominal ultrasound (US) during their hospital course. Of 84 patients who had both CT and US, 31 (37%) patients were diagnosed with gallstones by US versus 19 (23%) by CT. Biliary dila-tion/obstruction was diagnosed by US in 5 (6%) patients versus 4 (5%) by CT. CT led to the correct diagnosis or change in management in 21 (14.5%) patients. Conclusion: Early CT may alter the diagnosis or management in up to 15% of patients presenting to the ED with AP, especially older patients with prior episodes of pancreatitis and biliary interventions, however abdominal US may be a more sensitive screening study for biliary etiologies and thereby better direct further management. (c) 2021 Elsevier Inc. All rights reserved.