CT Imaging Findings of Ruptured Ovarian Endometriotic Cysts: Emphasis on the Differential Diagnosis with Ruptured Ovarian Functional Cysts

Objective: The purpose of this study is to assess the prevalence of abnormal CT fi ndings in patients with surgically proven ruptured endometriotic cysts, as compared with those abnormal CT fi ndings of ruptured ovarian functional cysts. Materials and Methods: This study included 13 retrospectively identified patients with surgically confirmed ruptured ovarian endometriotic cysts and who had also undergone preoperative CT scanning during the previous seven years. As a comparative group, 25 cases of surgically confi rmed ruptured ovarian functional cysts were included. We assessed the morphologic features of the cysts and the ancillary fi ndings based on CT. Results: For the endometriotic cysts, the mean maximum cyst diameter was signifi cantly larger than that of the functional cysts (70.1 mm versus 36.4 mm, respectively, p < 0.05). The endometriotic cysts frequently had a multilocular shape and a thicker cyst wall, as compared to that of functional cysts, and these differences were statistically signifi cant. Among the ancillary fi ndings, endometriotic cysts showed a signifi cantly higher prevalence of loculated ascites, ascites confi ned to the pelvic cavity without extension to the upper abdomen, and peritoneal strandings and infi ltrations (p < 0.05). Although 11 of the 25 cases of functional cysts showed active extravasation of contrast material at the ovarian bleeding site, only one of 13 cases of endometriotic cysts showed active extravasation. Conclusion: The diagnosis of ruptured endometriotic cyst should be suspected for a woman in whom CT reveals the presence of multilocular or bilateral ovarian cysts with a thick wall and loculated ascites confi ned to the pelvic cavity with pelvic fat infi ltrations.