Objective To explore the CT manifestations and diagnostic value of duodenal perforation. Methods CT findings and clinical data of 27 patients with duodenal perforation confirmed by surgery in people′s hospital of dangshan county from October 2010 to February 2019 were analyzed retrospectively.CT scan was performed from the diaphragmatic apex to the iliac crest

and the perforation site

causes

free gas distribution and adjacent structures were observed in multiple directions by combining with multiplane reconstruction technology. ResultsAll the 27 cases were perforated in the duodenal bulb

26 cases were isolated

and 1 case was perforated simultaneously in the anterior and posterior walls of the duodenal bulb.The free gas out of the duodenal cavity was mainly distributed around the liver

gallbladder fossa

hepatic fissure

liver and kidney space

liver and stomach space. In addition to free gas

2 patients were associated with irregular soft tissue highdensity shadows near the duodenal bulb with uneven density and unclear boundary to the gallbladder

9 patients had seroperitoneum

and 1 patient had bilateral pleural effusion.Conclusion CT has important diagnostic value for duodenal perforation. It has obvious advantages to judge the perforation site and infer the possible cause of perforation.