CT before and after ERCP: detection of pancreatic pseudotumor, asymptomatic retroperitoneal perforation, and duodenal diverticulum.

Background: A prospective study was done to investigate the occurrence of morphologic changes after ERCP that present as pancreatic pseudotumor on CT scan. Fifty-eight patients underwent CT before and after ERCP. In addition, post-ERCP complications and the value of routinely obtained CT before ERCP were assessed.

Results: Thirty-nine patients could be fully analyzed; 12 underwent a papillotomy (group 1). Pseudotumor of the pancreatic head was demonstrated on CT after ERCP in them (17%). No changes were seen in the 27 patients who underwent diagnostic ERCP (group 2) (p = 0.048). Asymptomatic retroperitoneal perforation after papillotomy was diagnosed in 3 patients (13%). Routinely obtained CT scans before ERCP defined a specific etiology of the biliary obstruction in 12% of patients not suggested by ultrasound. Duodenal diverticulum was found in 4 patients, resulting in a sensitivity of 36% and a specificity of 100% for CT. Oral contrast (600 ml) administered a few hours before endoscopy never hampered the endoscopist.

Conclusion: Pancreatic pseudotumor on CT after ERCP occurred only when papillotomy was performed. CT remains a valuable diagnostic tool after diagnostic ERCP. Asymptomatic perforation may occur following ERCP with papillotomy. Routinely obtained CT before ERCP was not profitable for the endoscopist in more than 80% of our patients.