{"paper_id":"91f0c3b5-ae4a-4025-b311-e10e4c3fab4f","body_text":"Korean J Radiol 12(1), Jan/Feb 2011www.kjronline.org 59\nINTRODUCTION\nThe reproductive tract is the commonest source of \nspontaneous hemoperitoneum in women of childbearing \nage. After ruling out an ectopic pregnancy, rupture of an \nCT Imaging Findings of Ruptured Ovarian Endometriotic \nCysts: Emphasis on the Differential Diagnosis with \nRuptured Ovarian Functional Cysts\nYoung Rae Lee, MD\nDepartment of Radiology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 110-746, Korea\nObjective: The purpose of this study is to assess the prevalence of abnormal CT fi ndings in patients with surgically proven \nruptured endometriotic cysts, as compared with those abnormal CT fi ndings of ruptured ovarian functional cysts. \nMaterials and Methods:  This study included 13 retrospectively identified patients with surgically confirmed ruptured \novarian endometriotic cysts and who had also undergone preoperative CT scanning during the previous seven years. As \na comparative group, 25 cases of surgically confi rmed ruptured ovarian functional cysts were included. We assessed the \nmorphologic features of the cysts and the ancillary fi ndings based on CT.\nResults: For the endometriotic cysts, the mean maximum cyst diameter was signifi cantly larger than that of the functional \ncysts (70.1 mm versus 36.4 mm, respectively, p < 0.05). The endometriotic cysts frequently had a multilocular shape and \na thicker cyst wall, as compared to that of functional cysts, and these differences were statistically signifi cant. Among the \nancillary fi ndings, endometriotic cysts showed a signifi cantly higher prevalence of loculated ascites, ascites confi ned to \nthe pelvic cavity without extension to the upper abdomen, and peritoneal strandings and infi ltrations (p < 0.05). Although \n11 of the 25 cases of functional cysts showed active extravasation of contrast material at the ovarian bleeding site, only \none of 13 cases of endometriotic cysts showed active extravasation. \nConclusion: The diagnosis of ruptured endometriotic cyst should be suspected for a woman in whom CT reveals the \npresence of multilocular or bilateral ovarian cysts with a thick wall and loculated ascites confi ned to the pelvic cavity with \npelvic fat infi ltrations. \nIndex terms: Endometriosis; Ovary; Cysts; Computed tomograpy (CT); Comparative studies; Pelvis\nReceived April 28, 2010; accepted after revision August 9, 2010.\nCorresponding author: Young Rae Lee, MD, Department of \nRadiology, Kangbuk Samsung Hospital, Sungkyunkwan University \nSchool of Medicine, 108 Pyeong-dong, Jongno-gu, Seoul 110-746, \nKorea.\n• Tel: (822) 2001-2337 • Fax: (822) 2001-1030 \n• E-mail: lesiles@chol.com\nThis is an Open Access article distributed under the terms of \nthe Creative Commons Attribution Non-Commercial License \n(http://creativecommons.org/licenses/by-nc/3.0) which permits \nunrestricted non-commercial use, distribution, and reproduction in \nany medium, provided the original work is properly cited. \nOriginal Article\nDOI: 10.3348/kjr.2011.12.1.59\npISSN 1229-6929 · eISSN 2005-8330\nKorean J Radiol 2011;12(1):59-65\novarian cyst is the most common cause of spontaneous \nhemoperitoneum in nonpregnant patients (1-3). Ovarian \ncyst rupture and hemorrhage are basically physiological \nevents that involve the follicle or corpus luteum, but when \nthe hemorrhage is large or a considerable quantity of fl uid \nis released from a cyst into the peritoneal cavity, this may \nresult in acute abdominal pain and/or pelvic pain from \nperitoneal irritation (2, 4). While ovarian endometriosis is \na very common condition in women of reproductive age, \nendometriotic cyst associated with rupture is an uncommon \ncondition. Nevertheless, this condition is important \nbecause it may require emergency surgery due to the severe \nabdominal pain secondary to chemical peritonitis when the \nfl uid contents fl ow out of the cysts (5).\nAlthough the imaging fi ndings of ovarian endometriotic \ncysts have been extensively described, less attention \n\nKorean J Radiol 12(1), Jan/Feb 2011 www.kjronline.org60\nYoung Rae Lee\nretrospectively assessed 25 cases of surgically confi rmed \nruptured ovarian functional cysts during the same period, \nand these cases included 21 cases of corpus luteal cysts \nand four cases of follicular cysts. All these patients had \nundergone pelviscopic laparotomy or open oophorectomy \nwithin one week after CT scanning. \nEver since 2005, the CT scans were performed by a \n40-slice Brilliance CT scanner (Philips Medical Systems, \nCleveland, OH) using a 0.5 mm detector collimation with 3 \nmm reconstruction. For the contrast-enhanced scans, 120 \nmL of nonionic contrast medium was administrated at a \nrate of 3 mL/s, with a scan delay of 60s. Prior to 2005, a \nGE HiSpeed Advantage CT (Milwaukee, WI) with helically \nacquired images at a collimation of 7 mm and a pitch of 1.0 \nwas used.\nThe clinical and laboratory data for age, the presence \nof leukocytosis and an abnormal hemoglobin level and \nhematocrit was obtained by a retrospective review of the \nmedical records: leukocytosis was a serum white cell blood \ncount higher than 10.2 x 10\n3\n/mm\n3\n, an abnormal hemoglobin \nlevel was a serum hemoglobin level lower than the standard \nvalue (11.0 g/dL) and an abnormal hematocrit was a \nserum hematocrit level lower than 34%. A single attending \nradiologist who specialized in genitourinary radiology \nand who had more than 15 years of experience and who \nwas without knowledge of the clinical and pathologic \nfi ndings recorded the morphologic features of the cysts \nand the ancillary fi ndings based on the CT: the maximum \ncyst diameter, bilaterality, multilocularity, the cyst \nhas been given to the imaging fi ndings of ruptured \nendometriotic cysts. Although ultrasound (US) and magnetic \nresonance imaging (MRI) remain the primary imaging \nmodalities for assessing women with suspected gynecologic \npathology, computed tomography (CT) is frequently \nperformed as the fi rst imaging modality for the evaluation \nof abdominal and pelvic pain of an unknown etiology (6). \nThe possibility of endometriosis is often overlooked as a \ncause when both ascites and a pelvic mass are found in the \nsame patient, and this is because the majority of ovarian \ncysts presenting with rupture or hemorrhage are functional \ncysts. As patients with endometriotic cysts frequently \nhave multiple associated peritoneal adhesions (7, 8), \nestablishing the correct diagnosis of ovarian cyst is crucial \nto help guide the surgical planning. The purpose of this \nstudy is to assess the prevalence of abnormal CT fi ndings \nof patients with surgically proven ruptured endometriotic \ncysts, as compared to the abnormal CT fi ndings of patients \nwith ruptured ovarian cysts. \nMATERIALS AND METHODS\nThe study population consisted of 13 patients with \nsurgically confi rmed ovarian endometriotic cysts associated \nwith rupture and who underwent preoperative CT from \nJanuary 2003 to December 2009, and the patients were \nassessed through a retrospective review of the hospital \nrecords and the operation database at Kangbuk Samsung \nHospital (Seoul, Korea). As a comparative group, we \nTable 1. Morphologic Characteristics of Ovarian Cysts and Prevalence of Ancillary Findings on CT Imaging of Women \nwith Ruptured Endometriotic Cysts and Functional Cysts\nCT Findings Endometriotic Cysts\n(n = 13)\nFunctional Cysts\n(n = 25) P value\nMaximum diameter (mm) 70.1 36.4 0.007*\nCyst density on noncontrast scan (HU) 35.07 22.33 0.977\nMaximum cyst wall thickness (mm ± SD) 2.92 (1.89) 2.14 (0.72) 0.002*\nBilaterality 4 2 0.07\nMultilocularity 7 2 0.002*\nCyst wall enhancement 11 25 0.202\nDisrupted cyst wall 4 16 0.07\nActive extravasations 1 11 0.02*\nAbdomen ascites 3 17 0.023*\nLoculated ascites 10 1 0.000*\nPeritoneal infi ltrations 7 3 0.002*\nNote.— *P values < 0.05 were considered statistically signifi cant. HU = Hounsfi eld unit, SD = standard deviation\n\nKorean J Radiol 12(1), Jan/Feb 2011www.kjronline.org 61\nCT Findings of Ruptured Ovarian Endometriotic Cysts\ndensity on the noncontrast scans, cyst wall enhancement, \nthe maximum thickness of the cyst wall, discontinuity \nor disruption of the cyst wall, active extravasations of \nintravenous contrast media around the cyst, the extent of \nascites, loculated ascites and the presence of peritoneal \ninfi ltrations.\n Statistical analysis was performed to compare the \ndifferences of the CT fi ndings. Differences in proportions \nwere analyzed by Fisher’s exact test, whereas continuous \nvariables were assessed by the t test. A p value of < 0.05 \nwas considered signifi cant. All the analyses were performed \nusing the SPSS program (SPSS version 17.0 software for \nWindow; SPSS, Chicago, IL). \nRESULTS\n For the endometriotic cysts, the mean age of the patients \nwith endometriotic cysts was older than that of the patients \nwith functional cysts (32.7 ± 7.30 years and 26.8 ± 6.95 \nyears, respectively), but the difference was not statistically \nsignifi cant. The prevalence of leukocytosis and a decreased \nhemoglobin or hematocrit level was not different between \nthe two groups.\nThe morphologic characteristics of the ovarian cysts and \nthe prevalence of the ancillary CT fi ndings of the ruptured \nendometriotic cysts and functional cysts are listed on Table \n1. For the endometriotic cysts, the mean maximum cyst \ndiameter was signifi cantly larger than that of the functional \ncysts (70.1 mm and 36.4 mm, respectively, p = 0.007). The \nA\nC\nB\nFig. 1. Ruptured left ovarian endometriotic cysts in 30-year-old woman with sudden onset of abdominal pain. Laboratory tests \ndetected serum CA-125 level that was elevated to 4034 IU/ml. \nA. Enhanced CT image shows 13-cm-sized cystic lesion in left ovary with crenulated hyperdense cyst wall with focal disruption on right posterior \nwall (arrows), which all suggested rupture. B. Image more caudal to A shows other cystic lesions of both ovaries with “kissing ovary sign” (arrows). \nC. Coronal reformatted enhanced image shows large fl uid collections in pelvic cavity (asterisks) and left ovarian cystic lesion with crenulated \nhyperdense cyst wall (arrows). Note haziness and strandings of mesenteric fat tissue suggesting associated infl ammatory reactions (white arrows).\n\nKorean J Radiol 12(1), Jan/Feb 2011 www.kjronline.org62\nYoung Rae Lee\nendometriotic cysts had a multilocular shape and a thicker \ncyst wall than did the functional cysts, and these differences \nwere statistically signifi cant. Seven of 11 patients with \nendometriotic cysts had bilateral endometriotic cysts (Fig. \n1), and only two of the 25 patients with functional cysts \nhad bilateral functional cysts, but this difference was \nnot statistically signifi cant (p = 0.07). Seventeen of 25 \nfunctional cysts (68%) had ruptures from the right adenxa, \nwhereas fi ve of 13 endometriotic cysts (38%) had a right \nsided rupture and one patient had bilateral rupture, but \nthe difference was not statistically signifi cant. Among \nthe ancillary fi ndings, there was a signifi cantly different \nprevalence of loculated ascites (Fig. 2), ascites confi ned to \nthe pelvic cavity without extension to the upper abdomen, \nand peritoneal strandings and infi ltrations in the patients \nwith endometriotic cysts as compared to that of the \npatients with functional cysts (Fig. 1). Although 11 of 25 \ncases of functional cysts showed active extravasation of \ncontrast material at an ovarian bleeding site, only one of \n13 cases of endometriotic cysts showed active extravasation \n(Fig. 3). Focal discontinuity or a disrupted wall was more \nprevalent in the ruptured functional cysts than that of the \nendometriotic cysts, but this difference was not statistically \nsignifi cant. \nAB\nFig. 2. Ruptured left ovarian endometriotic cysts in 27-year-old woman. \nA. Enhanced CT image shows localized pelvic ascites in posterior cul de sac (asterisk). B. Image more cranial to A shows multiple cysts or \nmultilocular cyst of left ovary with hyperdense wall and focal wall disruption (arrow). Laparoscopic wedge resection of left ovary was performed \nand lesion proved to endometriotic cyst. \nAB\nFig. 3. 20-year-old woman presented with severe pelvic pain and negative β HCG test. \nA. Enhanced CT image at level of uterus shows large amount of high-attenuation fl uid in pelvis due to hemoperitoneum (asterisks). B. Enhanced \nscan more cephalad to A depicts jet of contrast material from right ovarian cyst wall (arrows), suggesting active bleeding site. Surgery confi rmed \nruptured corpus luteal cyst of right ovary.\n\nKorean J Radiol 12(1), Jan/Feb 2011www.kjronline.org 63\nCT Findings of Ruptured Ovarian Endometriotic Cysts\nDISCUSSION\nEndometriosis corresponds to the ectopic endometrial \nglands and stroma outside the uterine cavity. The clinical \nsymptoms include dysmenorrhea, dyspareunia, infertility, \npainful defecation or cyclic urinary symptoms (7). \nEndometriotic cysts generally occur within the ovaries and \nthey are the result of repeated cyclic hemorrhage within \na deep implant. These cysts can completely replace the \nnormal ovarian tissue (8). \nFocal leaks with infl ammation, fi brosis and adhesion \nformation are characteristics of endometriosis, whereas \nacute cyst rupture is a relatively uncommon complication \n(8). Such cases of acute cyst rupture are rare, but they \nmay be associated with severe peritonitis and systemic \ndisturbance, followed by adhesion formation (9, 10). A \ntheory on the formation of ascites in endometriosis was \npostulated by Bernstein et al. (11), who suggested that the \nblood and endometrial cells shed into the peritoneal cavity \nmay irritate and stimulate the peritoneum, thereby resulting \nin ascites. Other authors have reported that rupture of \nendometriotic cysts with subsequent peritoneal irritation \nand the production of reactive exudates may provide an \nexplanation (12). Ruptured endometriotic cysts sometimes \npresent a diagnostic problem and surgical challenge because \npatients with a ruptured cyst present with symptoms of an \nacute abdomen associated with severe abdominal pain and \nunstable vital signs (8). Ruptured ovarian endometriotic \ncysts can sometimes mimic ovarian malignancy because of \nthe extremely elevated serum CA 125 concentration (9, 13).\nThe US and MRI aspects of endometriosis, as reported in \nthe literature, are variable depending on many structural \nand morphologic factors (8, 14\n-16). The CT appearance \nof endometriotic cysts is nonspecifi c and this includes a \nspectrum from simple cystic to complex cystic masses (8, \n17, 18). Buy et al. (19) reported that the CT fi ndings of a \nhyperdense focus inside an ovarian cyst are suggestive of \nendometriotic cysts. However, this is nonspecifi c because \nother hemorrhagic lesions, such as hemorrhagic cysts, may \nalso demonstrate this fi nding (8). Multiple lesions increase \nthe specifi city for the diagnosis of endometriomas because \nendometriomas are often multiple (20).\nEndometriotic cysts are more often multiple or bilateral, \nas opposed to other hemorrhagic cysts that are usually \nunilateral (8, 21); when associated with interovarian \nadhesions, endometriotic cysts are often described as \n“kissing” ovaries (22). In our study, seven of the 13 cases \nof ruptured endometriotic cysts showed bilateral lesions, as \ncompared to only two cases of bilateral functional cysts.\nAccording to the results of this study, the endometriotic \ncysts are multilocular and they have a thicker cyst wall \nas compared to that of functional cysts. The multilocular-\nappearing endometriotic cyst may actually consist of \nmultiple separate cysts (8). Thin or thick septations may be \npresent between these loculi. One study showed that in the \nabsence of wall nodularity and in the presence of diffuse \nlow-level echoes, a multiloculated mass was 64 times \nmore likely to be an endometriotic cyst (23). When using \ndiagnostic MRI criteria such as T1 hyperintense cysts with \nT2 shading or multiple T1 hyperintense cysts regardless of \nthe T2 signal intensity, the sensitivity and specifi city for \nmaking a defi nitive diagnosis of endometriotic cysts have \nbeen reported to be as high as 90% and 98%, respectively \n(15).\nThe mean maximum diameter of the ruptured \nendometriotic cysts is 70.1 mm in this study, which is larger \nthan that of the uncomplicated ovarian endometriotic cysts \nreported in the previous studies. Kinkel et al. (7) reported \nthat 81% of ovarian endometriotic cysts ranged between 30 \nmm and 59 mm for the maximum diameter. If endometriotic \ncysts get large enough or if trauma occurs, then they can \nrupture and their contents spill into the pelvic cavity. \nUnruptured corpus luteal cysts are typically less than 3 cm \nin diameter (24).\nThe cyst walls in endometriotic cysts are generally thick \nand fi brotic, and they commonly have areas of discoloration \nand dense fi brous adhesions. The US appearance of the \nendometrial cyst wall can be variable, but this deserves \nspecial attention (8). Diffuse wall thickening, wall \nnodularity and echogenic foci within the cyst wall of \nendometriotic cysts have all been observed (23). Patel et \nal. (23) found no diagnostic value in assessing the wall \nthickness for differentiating between endometriotic cysts \nand other ovarian masses. On MR imaging, administration \nof gadolinium-based contrast material is not particularly \nuseful for evaluating endometriotic cysts (8). When contrast \nmaterial is used, the cyst wall demonstrates a nonspecifi c, \nvariable pattern of enhancement that does not differentiate \nit from other benign and malignant processes (25). In our \nstudy, the relatively high incidence of enhancement of the \ncyst wall after intravenous contrast administration (11 of \n13 cases) was suggestive of active infl ammatory changes \ndue to cyst rupture. In patients with ruptured corpus luteal \ncysts, CT typically reveals hemoperitoneum and an adnexal \n\nKorean J Radiol 12(1), Jan/Feb 2011 www.kjronline.org64\nYoung Rae Lee\ncyst, with a ring of peripheral contrast enhancement \n(2). This ring of contrast enhancement may be due to \nthe increased vascularity during the luteal phase, which \npredisposes the cyst to rupture (26). \nIn a patient suffering from hemoperitoneum, active \nbleeding as depicted at CT by the active arterial \nextravasation of intravenous contrast with a measured \nattenuation value higher than that of free or clotted blood \nis indicative of the need for prompt surgical intervention \n(4). A focus of active bleeding may appear as a serpiginous \nor amorphous high attenuation area that is intermixed \nwith or surrounded by a large hematoma (1). The wall \nof an endometriotic cyst is mostly fi brotic tissue with \na paucity of vascularity; therefore, only one of the 13 \ncases of endometriotic cysts in our study showed active \nextravasation, while 11 of the 25 cases of functional cysts \nshowed this fi nding. \nIn patients with ruptured endometriotic cysts, the ascites \nis usually confi ned to the pelvic cavity with a loculated \ncontour, and this suggests associated pelvic adhesion, \nwhich is an extremely common and important complication \nof endometriosis (8). After a corpus luteal cyst ruptures, \nhemoperitoneum will be present within the pelvis and \npossibly throughout the abdomen, as was shown in this \nstudy. Higher attenuation blood is typically present within \nthe pelvis, as compared with being present the abdomen, \nand blood may be present adjacent to the cystic lesion, \nindicating that the source of the hemoperitoneum is cyst \nrupture (2).\nSeveral limitations of our present study must be \nconsidered. First, it was a retrospective evaluation with a \nrelatively small number of patients. Second, the present \nstudy was confi ned to patients with functional cysts \nas a comparative group, and we did not include any \npatients with conditions such as tuboovarian abscess \nor ovarian tumor that might potentially overlap with \novarian endometriotic cysts on CT. Third, the patients \nwith ruptured corpus luteal cysts and who had a small \namount of hemoperitoneum confi ned to the pelvic cavity \nwere managed conservatively, and this may have caused a \nselection bias. Fourth, the CT protocol was not identical for \nall the enrolled patients. Finally, in this study, the images \nwere reviewed and analyzed by only a single reader. \n That being said, the CT appearance of ruptured \nendometriotic cysts is relatively distinctive compared \nto that of ruptured functional cysts, and the accurate \npreoperative characterization of ovarian cyst via CT will \nhelp the surgical planning. 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