Atypical cases of gallstone ileus evaluated with multidetector computed tomography

Objective: To describe the multidetector computed tomography (CT) findings in 3 patients with atypical gallstone ileus. Methods: We retrospectively evaluated computed radiography and CT images from three cases of surgically proven gallstone ileus. Two radiologists evaluated by consensus all images for the presence of ectopic gallstone, small bowel obstruction, intrahepatic pneumobilia, cholecystic pneumobilia. One author recorded whether diagnosis of gallstone ileus was made prospectively on radiologic reports and correlated findings to pathology. Results: All cases of gallstone ileus were atypical in that one patient had porcelain gallbladder, one had recurrent pyogenic cholangitis, and one was only 35 years of age. Prospective clinical diagnosis of gallstone ileus was made in only 1 patient at computed radiography and all 3 patients at CT. Retrospectively, small bowel obstruction and cholecystic pneumobilia were identified retrospectively in all 3 patients at both computed radiography and MDCT, and an ectopic gallstone, intrahepatic pneumobilia, and choledochoduodenal fistula was seen in 2, 1, and 0 patients at computed radiography and 3, 2, and 3 patients at CT respectively. Conclusion: Multidetector CT is an accurate means to diagnose gallstone ileus, even in patients with atypical features. In particular, multidetector CT is useful for identifying the ectopic gallstone at the transition point between dilated and decompressed bowel.