8Cho HS,Yoon SE,Park SH,et al.Distinction between upper and lower gastrointestinal perforation:usefulness of the periportal free air sign on computed tomography.Eur J Radiol,2009,69(1):108-113.
9Oguro S,Funabiki T,Hosoda K,et al.64-slice multidetector computed tomography evaluation of gastrointestinal tract perforation site:detectability of direct findings in upper and lower GI tract.Eur Radiol,2010,20(6):1396-1403.
10Pinto A,Scaglione M,Giovine S,et al.Comparison between the site of multislice CT signs of gastrointestinal perforation and the site of perforation detected at surgery in forty perforated patients.Radiol Med,2004,108(3):208-217.