This is the final version. Available on open access from Mattioli 1885 via the DOI in this recordBackground and aim: The impact of different aetiologies of acute pancreatitis on the development of pancreatic necrosis (PN) is unclear. This study assessed the extent and progression of pancreatic and peripan-creatic necrosis on the computed tomography (CT) scan of patients with gallstone (GP) and alcohol-induced (AIP) pancreatitis and evaluated their impact on disease severity. Methods: Patients ≥ 18-year-old with GP, AIP and PN on CT ( January 2010 – September 2018), were considered. The radiological extent of PN and clinical outcomes were analysed with a logistic regression model. Results: Eighty-one patients, 59 with GP, 22 with AIP, were included. GP had a larger extent of PN when the body and/or tail of the pancreas were involved (P = 0.009). Gallstone disease (P = 0.028) and higher American Society of Anesthetists scores (P = 0.043) were predictors of necrosis diffuse to different areas of the pancreas. Predictors of single/multiple organ failure were GP (P = 0.040), necrosis > 50% of the pancreas (P = 0.002) with a diffuse pattern (P = 0.004). Conclusions: Patients with GP had a wider extent of necrosis in the pancreatic body and/or tail. The onset of organ failure can be predicted in subjects with GP and larger amount of PN
