Usefulness of Apparent Diffusion Coefficient in Ovarian Cystic Tumors Using Diffusion-Weighted Magnetic Resonance Imaging

PURPOSE: To evaluate the usefulness of apparent diffusion coefficient (ADC) values using diffusion-weighted magnetic resonance imaging (DWI) in patients with ovarian cystic tumors. MATERIALS AND METHODS: During past 12 months, we studied 30 patients who were clinically suspected of having ovarian cystic tumors and who underwent DWI using a 1.5 T MR unit. Eight patients with small cystic ovarian lesions of less than 3 cm in diameter and insufficient DWI were excluded from the calculation of the ADC values. The remaining twenty-six cystic ovarian lesions in 22 patients were classified into four groups; ovarian cysts, cystadenomas, other benign tumors, and malignant tumors. DWI was obtained using single-shot spin echo planar imaging and two gradient steps (b values of 0, 800 sec/mm2). The ADC values were measured using regions-of-interest (ROI) in the cystic components of the DWI located in the same section as the T2-weighted image and away from the septation and solid components. RESULTS: The mean ADC values were 0.196+/-0.105x10(-3) mm2/sec in the ovarian cysts, 1.312+/-1.064x10(-3) mm2/sec in the cystadenomas, 0.274+/-0.124x10(-3) mm2/sec in the other benign tumors, and 1.011+/-0.080x10(-3) mm2/sec in the malignant tumors. The differences in the ADC values between the ovarian cysts and cystadenomas, the ovarian cysts and malignant tumors, the cystadenomas and other benign tumors, and the other benign tumors and malignant tumors were statistically significant (p 0.05). CONCLUSION: The calculated ADC values using DWI should be helpful in the differential diagnosis of cystic ovarian tumors.

MR Imaging of Pregnancy Luteoma: a Case Report and Correlation with the Clinical Features

We report here on a 26-year-old pregnant female who developed hirsutism and virilization during her third trimester along with a significantly elevated serum testosterone level. Abdominal US and MR imaging studies were performed, and they showed unique imaging features that may suggest the diagnosis of pregnancy luteoma in the clinical context. After the delivery, the serum testosterone level continued to decrease, and it returned to normal three weeks postpartum. The follow-up imaging findings were closely correlated with the clinical presentation.

Detection of Contralateral Normal Ovary in Patients with Large(>10 cm) Unilateral Ovarian Mass by Using MRI

PURPOSE: To assess the usefulness of MRI for determining the presence of a large (>10 cm) unilateral ovarian tumor by detecting the existence of a normal contralateral ovary, and to establish the difference in detection rates between premenopausal and postmenopausal women, and benign and malignant tumors. MATERIALS AND METHUDS: Materials and Methods: Forty-two patients who underwent MR imaging and in whom the intraoperative gross and pathologic findings indicated the preseace of a unilateral ovarian mass and a normal contralateral ovary were included in this study. The images obtained were retrospectively analyzed by two radiologists, who determined the detection rate of the normal contralateral ovary and whether this differed between premenopausal and postmenopausal women, and benign and malignant tumors. RESULTS: Contralateral normal ovaries were detected in 35 (83.3%) of 42 patients [22 of 23 ovaries (95.7%) in premenopausal women and 13 of 19 (68.4%) in postmenopausal women], with a statistically significant difference (p=0.018). Twelve of 16 of these ovaries (75%) were present in women with malignant tumors, and 23 (88.5%) of 26 in those with benign tumors, but the difference was not statistically significant (p=0.256). CONCLUSION: MR imaging is useful for detecting a normal contralateral ovary and for determining the site at which a large (>10 cm) unilateral ovarian tumor originates, especially in premenopausal women.

MR Findings of Malignant Struma Ovarii Associated with Mature Cystic Teratoma of Contralateral Ovary: Case Report

Malignant struma ovarii is a rare form of ovarian carcinoma. Sincc it is often seen as a nonspecific complex mass, its preoperative diagnosis is difficult. The MR imaging findings of benign struma ovarii have been reported, but no published account has described the malignant form. In this case, MR images depicted multiple cysts with well enhanced solid portions in the left ovary, and the typical apperarance of mature cystic teratoma in the right ovary. We describe a case of malignant struma ovarii associated with mature cystic teratoma of the contralateral ovary.

Sclerosing Stromal Tumor of the Ovary: MR-Pathologic Correlation in Three Cases

Sclerosing stromal tumor (SST) of the ovary is a very rare sex cord stromal tumor occurring in a younger age group than other types of stromal tumors and most commonly accompanied by menstrual irregularity. Several unique histologic features including pseudolobulation, sclerosis and prominent vascularity are clearly reflected at ultrasonography and MRI. We report the ultrasonographic and MR features of three cases of histologically confirmed SSTs, and relate them to the pathological findings.

In-vivo Proton Magnetic Resonance Spectroscopy in Adnexal Lesions

OBJECTIVE: To explore the in-vivo 1H- MR spectral features of adnexal lesions and to characterize the spectral patterns of various pathologic entities. MATERIALS AND METHODS: Thirty-one patients with surgically and histopathologically confirmed adnexal lesions underwent short echo-time STEAM (stimulated echo acquisition method) 1H- MR spectroscopy, and the results obtained were analysed. RESULTS: The methylene present in fatty acid chains gave rise to a lipid peak of 1.3 ppm in the 1H- MR spectra of most malignant tumors and benign teratomas. This same peak was not observed, however, in the spectra of benign ovarian epithelial tumors: in a number of these, a peak of 5.2 ppm, due to the presence of the olefine group (-CH=CH-) was noted. The ratios of lipid peak at 1.3 ppm to water peak (lipid/water ratios) varied between disease groups, and in some benign teratomas was characteristically high. CONCLUSION: An intense lipid peak at 1.3 ppm is observed in malignant ovarian tumors but not in benign epithelial tumors. 1H- MRS may therefore be helpful in the differential diagnosis of adnexal lesions.

MR Imaging of Normal Ovary in Menstruating Women: Detection Rate and Size of the Ovary and the Number and Size of the Follicle According to the Age

PURPOSE: To determine the rates at which normal ovaries in women of reproductive age were observed at MRI, as well as differences in the size of a normal ovary and follicles, and the number of follicles, according to age. MATERIALS AND METHODS: The MRI findings in 46 patients with normal ovaries were retrospectively analysed and proven grossly at surgery and/or pathologically. The detection rate and size of the ovaries, and the number of follicles and size of the largest were determined, and differences were analyzed according to age: under 30, 30-39, and 40 years or over. RESULTS: Among 46 patients, bilateral ovaries were detected in 39 and unilateral ovary in seven. The overall detection rate was 92.4% (85/92), varying according to age. It was 100% (18/18) in those aged under 30, 95% (38/40) in the 30-40 age group, and 85.3% (29/34) among those aged 40 or over. Ovary size ranged between 15 and 50 (average, 24.3) mm and was most commonly 20-30 mm, regardless of age (60%). The average size was 28.8 mm under 30 years of age, 25.3 mm between 30 and 39, and 20.3 mm at age 40 or over (p<0.01). The number of follicles was recorded as 2, 3, 4, or 5 or more, with 10.6%, 23.5%, 18.8% and 47.1% of patients, respectively, assigned to these categories. Among those aged 30-39, ovaries containing five or more follicles were most common, with 83.3% of those under 30 and 47.4% of those aged 30-39 falling into this category. Among patients aged 40 or over, only 24.1% of ovaries contained five or more follicles; most (37.9%) contained three (p<0.05). The size of the largest follicle ranged from 2 to 30 mm and, regardless of age, 5-10-mm follicles were most common (43.5%). There were no significant differences according to age. CONCLUSION: MRI is a useful tool for detecting normal ovaries in women of reproductive age. We found that most normal ovaries were 20-30 mm in size and contained five follicles or more, the largest follicle being 5-10 mm. The size of an ovary and the number of follicles decreased significantly with age.

Change of Ovary Before and After Radiotherapy in Reproductive Women with Cervix Carcinoma in MR Imaging

PURPOSE: To investigate changes in the ovary revealed by MR imaging before and after radiotherapy in premenopausal patients with cervical carcinoma. MATERIALS AND METHODS: Thirty-three premenopausal patients with cervical carcinoma underwent radiation therapy at an average dosage of 11,279 (external: 5,352; internal: 5,927) cGy. Before and after this therapy, all underwent pelvic MR imaging using a 1.5T MR scanner (GE Medical Systems, Milwaukee, U.S.A.). The average interval of follow-up MR imaging was 7.2 months, and axial T1-weighted and axial and sagittal T2-weighted MR images were obtained. The presence, size number of follicles, and differentiation of the zonal anatomy of the ovary were determined by two radiologists, who reached a consensus. RESULTS: After radiation therapy, all patients ceased menstruation. For ovaries, the detection rates before and after radiation therapy were 94% (62/66) and 39% (26/66) (p<0.05), respectively, and average ovary size was 2.6x1.9x2.2 cm before and 1.7x1.3x1.4 cm after therapy (p<0.05). The average number of ovarian follicles before and after therapy was 5.1 and 3.1, respectively (p<0.05). T2-weighted imaging, demonstrated differentiation of zonal anatomy in 74% of cases (46/62) before radiotheraphy, and 15% (4/26) after (p<0.05). CONCLUSION: Our study has shown that after radiation therapy in premenopausal patients with cervical cancer, detection rates, average size, and the number of ovaries decreased, findings which are similar to those for normal postmenopausal ovary. MR imaging can reveal structural change in ovaries.

Huge Endometrioma Mimicking Mucinous Cystadenoma on MR: A Case Report

Endometriosis is a relatively common gynecologic disease affecting women during their reproductive years. For its diagnosis, magnetic resonance imaging has been shown to have greater specificity than other modalities. Although lesions may show variable signal intensity due to numerous stages of bleeding, the characteristic finding of endometrioma which distinguishes it from other ovarian cystic masses is relatively high signal intensity on T1-weighted images and heterogeneous signal intensity with prominent shading on T2-weighted images. We report an atypical case involving a huge endometrioma. Because of varying signal intensity on T1- and T2-weighted images and scanty shading on T2-weighted images, the findings were misinterpreted and mucinous cystadenoma was diagnosed.

Differentiation between Ovarian Fibroma and Subserosal Leiomyoma by MR Imaging

PURPOSE: To evaluate the findings and differential points of ovarian fibroma and subserosal leiomyoma, as seen on MR images. MATERIALS AND METHODS: The MR imaging findings of 31 surgically confirmed cases of ovarian fibroma(n=6) and subserosal leiomyoma (n=25 ; 28 lesions) were evaluated. Multiplanar T1- and T2-weighted and postcon-trast T1-weighted images were obtained using a 1.5T MR unit, and histologic examination was also performed. The MR findings were analyzed in terms of signal intensity, the presence and definition of margin, the histo-logic finding of hyperintense lesion on T2-weighted images, the presence of the bridging vessel sign, degree of enhancement, and the presence of ipsilateral ovary and ascites. RESULTS: Both fibromas and leiomyomas showed hypo-or isointensity compared with uterine myometrium on T1-weighted images and compared with skeletal muscle on T2-weighted images. The latter revealed intratu-moral hyperintense lesions in most cases of ovarian fibroma and subserosal leiomyoma. Three of four ovarian fibromas had a well defined margin after cystic change, but in 24 of 26 subserosal leiomyomas the margin was ill defined. The "bridging vessel sign" was visible only in subserosal leiomyomas (22/28), and in all cases the enhancement of ovarian fibromas were less than that of myomtetrium. Subserosal leiomyomas (12/28), seen on enhancement as isointense or hyperintense to myometrium, showed a greater degree of enhancement than ovarian fibromas (0/6). Ipsilateral ovary was rarely seen in ovarian fibromas (1/6), but commonly seen in sub-serosal leiomyomas (20/25). Ascites was present in one case of ovarian fibroma. CONCLUSION: A defined margin of an intratumoral hyperintense lesion, as seen on T2-weighted images, and the presence or absence of the "bridging vessel sign" and ipsilateral ovary are useful signs when differentiating be-tween ovarian fibromas and subserosal leiomyomas.

Radiologic Findings of Ovarian Fibrothe

PURPOSE: To evaluate the radiologic features of fibrothecoma of the ovary, which is a rare solid tumor originating from the ovarian sex cord-stroma. MATERIALS AND METHODS: The radiologic findings of 29 patients with pathologically-proven fibrothecoma of the ovary were retrospectively evaluated for bilaterality, size, shape, margin, echogenecity, CT attenuation, signal intensity on magnetic resonance imaging, calcification, and amount of ascites. RESULTS: All fibrothecomas were unilateral, and had well defined margins. The diameter of the mass was 4-18(mean, 9.6)cms. Elghteen of 29 tumors were round or oval with a smooth margin, and eleven were lobulated. The internal architecture of the tumor was purely solid in 21 patients, predominantly solid in six, and pre-dominantly cystic in two. A broad spectrum of sonographic features was apparent, including a homogeneously hypoechoic mass (with posterior shadowing in four cases, and without posterior shadowing in ten), a homoge-neously hyperechoic mass in seven cases, an anechoic mass with septatations in two, and a mixed echoic mass in six. On precontrast CT scans, the mass was isodense to the uterine myometrium in eight of nine cases, while on postcontrast scans the lesion was slightly hypodense to the myometrium in seven cases and isodense in one. On T1-weighted MR images, nine of ten cases showed a relatively homogeneous low signal intensity, while on T2-weighted images, signal intensity was homogeneously low in two patients and predominantly low with focal high intensity in seven of the other eight. On gadolinium-enhanced T1-weighted images, most tu-mors showed slight heterogeneous enhancement. Calcifications were present in two cases, and in two others there was a large amount of ascites. CONCLUSION: The characteristic finding of ovarian fibrothecomas is a well-defined, oval or lobulated homoge-neously solid mass, which on CT scans enhances less than uterine myometrium and demonstrates a predomi-nantly low signal intensity on both T1- and T2-weighted images. However, a predominantly solid mass with cystic components or a predominantly cystic mass may also be presented.

MR Findings of a Primary Ovarian Lymphoma

The imaging findings of primary ovarian lymphoma have not been reported, and, we therefore describe the MRI(magnetic resonance imaging) findings of a case of this disease, which manifested as bilateral lobulated solid masses with heterogenous signal intensity and central feeding vessels.

Radiologic Findings of Malignant Tumors Arising from Ovarian Endometriosis

PURPOSE: To determine the radiologic characteristics of malignant tumors arising from ovarian endometriosis. MATERIALS AND METHODS: The radiologic findings of eleven patients with pelvic masses histologically confirmed as malignant ovarian tumors arising from endometriosis were retrospectively reviewed. All patients underwent MR, and six underwent ultrasonography. The findings were evaluated with regard to tumor size and shape, locularity, thickness and enhancement of the wall and septa, the presence of papillary nodule or solid portion, signal intensity of the locule, the presence of mass in contralateral ovary, ascites, local invasion, distant metastases, and the Pathologic diagnosis included clear cell carcinoma in six cases, endometrioid carcinoma in three, and mucinous cystadenocarcinoma of borderline malignancy and endometrial stromal sarcoma in one case each. RESULTS: Tumor size ranged from 8 to 20 (mean, 12.7) cm. The tumors were mixed in four cases, entirely cystic in three, predominantly cystic in three, and predominantly solid in one. Six cases were unilocular and five were multilocular. The wall and septa varied in thickness and regularity and were well enhanced in all but one case. In all cases papillary nodules or solid portions with similar enhancement to uterine myometrium were seen. On T1WI, the signal intensity of fluid was seen to be high in eight cases, low or intermediate in two, and of differing intensity in one. Ten cases showed high signal intensity on T2WI, whereas in one case in which high signal intensity was seen on T1WI, there was low signal intensity(shading). In threee cases the contralateral ovary contained an endometrioma. Other features included ascites in seven cases and peritoneal seeding in one. CONCLUSION: Malignant ovarian tumors arising from endometriosis showed radiologic features of malignancy:they were larger than 10cm, there was enhancement of the wall and septa, and a papillary nodule or solid portion was present. However, the presence of hyperintense fluid, as seen on T1WI, as well as shading, differing signal intensity, a non-enhanced wall and septa, and endometriosis on the contralateral ovary suggests that a malignant tumor may arise from an underlying endometrioma.

MR Findings of Struma Ovarii

PURPOSE: To characterize the magnetic resonance (MR) findings of struma ovarii, a rare ovarian tumor composedsolely or predominantly of thyroid tissue or the tumor in which hyperthyroidism results from the ovarian thyroidtissue. MATERIALS AND METHODS: In seven patients, MR images (T1-weighted with or without gadolinium enhance-mentand T2-weighted) were obtained in the axial, coronal, and sagittal planes using 1.5-T MR units, and in three ofseven patients the fat saturation technique were performed. MR findings were retrospectively evaluat-ed for thesite, size, components, signal intensity, presence and degree of contrast enhancement, and associat-ed findings.These and pathologic findings were compared. RESULTS: MR images showed unilateral complex masses composed ofmultiple cysts and some solid components, corresponding pathologically to thyroid follicles containing colloid andthe stroma with abundant blood vessels and fibrous tissue. Cystic portions of the tumors had variable signalintensities on T1-weighted images, and high signal intensities on T2-weighted images. Some hyperintense cysticareas seen on T1-weighted images were due to hemorrhage (n=1) and colloid components (n=3). Solid portions of thetumors were isointense relative to adjacent muscles (with intense contrast enhancement), as seen on T1-weightedimages, and iso- or hyperintense on T2-weighted images. CONCLUSION: Struma ovarii has a characteristic MRappearance of a complex mass composed of multiple cysts and intensely enhanced solid components.

MR Imaging Differentiation of Endometrial Cysts from Hemorrhagic Cysts

PURPOSE: To differentiate endometrial cysts from hemorrhagic cysts on the basis of MR findings MATERIALS AND METHODS: The MR findings of twelve patients with endometrial cysts(15 cases) and of nine patients withhemorrhagic cyst(12 cases) were retrospectively evaluated. Fourteen patients were surgically corfirmed and sevenwith hemorrhagic cysts were clinically diagnosed by resolution of the cysts during ultrasound follow up. Sixteenpatients underwent MR imaging using a 1.5T system(Magnetom Vision, Siemens, Germany), and for five patients a 2.0Tsystem(Spectro 2000, Goldstar, Korea) was used. MR images were retrospectively evaluated with respect to size andsignal intensity of the cyst, uni/multilocularity, shading, the hematocrit effect, clot.., fluid-fluid level andseptum, and thickness, signal intensity and enhancement of the cyst wall. RESULT: Eleven(73.3%) endometrial cystswere multilocular, but all hemorrhagic cysts were unilocular. The signal was hyperintense on both T1WI and T2WI inten(66.7%) endometrial cysts and seven(58.3%) hemorrhagic cysts. Shading was found in five(33.3%) and one(8.3%),respectively; the hematocrit effect in two(13.3%) and five(41.7%) respectively, clot in two of each type(13.3%,16.7%), and fluid-fluid level in only one hemorrhagic cyst. Septum was found only in endometrial cysts(five cases,33.3%); its signal intensity on both T1WI and T2WI was low, and on Gd-enhanced images was not enhanced. The cystwall was thick in five of each type(33.3%, 41.7%); its signal intensity was low on both T1WI and T2WI, and notenhanced on Gd-enhanced images. In eight hemorrhagic cysts, however, the cyst wall was iso to high in signalintensity on both T1WI & T2WI, and was enhanced on Gd-enhanced images. The prevalence of uni/ multilocularity,septum, and signal intensity and the presence of enhancement of the cyst wall were significantly different between the two groups(p< 0.005). CONCLUSION: Uni/ multilocularity, septum, and signal intensity and enhancement of thecyst wall were useful for the differentiation of endometrial from hemorrhagic cysts. Signal intensity of the cyst,shading, the hematocrit effect and clot were not helpful.

Radiologic Findings of Ovarian Borderline Malignancy

PURPOSE: Ovarian epithelial tumors of borderline malignancy belong to a disease entity distnct from that ofbenign and overt malignant tumors, and the younger age of patients and earlier stage at diagnosis compared withinvasive ovarian cancers makes conservative surgery an important issue. The purpose of this study was to evaluatewhether there are any characteristic radiologic findings to suggest the presence of these tumors. MATERIALS AND METHODS: In 20 pathologically proven tumors of ovarian borderline malignancy, the findings of ultrasonography (n= 17) (with color Doppler ultrasonography in two cases), computed tomography (n = 8), or magnetic resonanceimaging (n = 6) were compared with pathologic findings and, were retrospectively reviewed and analyzed. Imageswere evaluated for size, loculation, thickness and regularity of wall and septum, endocystic vegetation, solidportion, calcification, local invasion and distant metastasis. RESULTS: Among 20 unilateral tumors, 18 weremucinous and two were serous; 19 (95%) were at stage I, and one was at stage II (local invasion of uterus, leftpara-aortic lymphadenopathy, and malignant ascites). Tumor size ranged from 10 - 40 cm in the largest diameter(mean, 21 cm). Radiologic findings of thick, irregular wall or septum were notified in 14 tumors (70%), endocysticvegetation in 12 (60%), enhancing solid portion in 11 (55%), and calcification in two (10%). Of 18 mucinoustumors, 17 (94%) were multilocular. One serous tumor was unilocular and one was multilocular. Color Dopplerultrasonography of two mucinous tumors revealed blood flow signals in the wall, septum, solid portion orendocystic vegetation, and resistive indices were 0.5 and 0.4, respectively. CONCLUSION: When ovarian tumors arepresent - especially in young females and at a lower stage -, radiologic findings of a thick, irregular wall orseptum, endocystic vegetation, and a small enhanced solid component, for example, indicate the possibility ofovarian epithelial tumors of borderline malignancy.

Radiologic Findings of Endodermal Sinus Tumor of the Ovary

PURPOSE: To evaluate the radiologic features of endodermal sinus tumor of the ovary. MATERIALS AND METHODS:The radiologic findings of eight patients with pathologically-proven endodermal sinus tumor of the ovary wereretrospectively evaluated for bilaterality, size, margin, architecture, septa, local invasion, distant metastasis,ascites and lymphadenopathy ; serum alpha-FP was also evaluated. RESULTS: All endodermal sinus tumors were unilateralwith irregular septa and ascites ; the longest diameter was 7-18(mean, 12.6)cm. Four of eight tumors had smoothmargins and four, lobulated. Four were predominantly cystic in internal architecture, one was purely cystic, andthree were predominantly solid. There was local invasion or distant metastasis in three patients, andretroperitoneal lymphadenopathy in one ; in seven cases, alpha-FP level was more than 1.000ng/ml. CONCLUSION: Endodermal sinus tumors of the ovary appeared as nonspecific large complex abdominal masses and it was difficultto differentiate them from other malignant ovarian tumors. This tumor should be included in the differentialdiagnosis of a large complex abdominal mass in girls and young women, especially in patients with a predominantlycystic mass and markedly elevated serum alpha-FP.

MR Imaging Findings of Ovarian Epithelial Tumor: Emphasis on Borderline Malignancy

PURPOSE: To evaluate the role of MR in the diagnosis of borderline epithelial tumors of the ovary comparedwith that of benign and malignant tumors. MATERIALS AND METHODS: MR images of 42 ovarian epithelial tumors in 39patients were retrospectively analyzed, focusing on the morphologic characters distinguishing borderlineepithelial tumors from benign and malignant tumors. All images were obtained using a 1.5T imager 3-27 (mean, 12)days before surgery. The size, shape, internal signal intensity, wall and septal thickness, papillary nodule,solid component, and contrast enhancement of the tumor were evaluated. RESULTS: Histopathologic diagnoses were 16serous epithelial tumors [benign (SB) 3, borderline malignancy (SBM) 5, malignancy (SM) 8]; 24 mucinous epithelialtumors [benign (MB) 11, borderline malignancy (MBM) 9, malignant (MM) 4]; one endometrial carcinoma (EC), and oneclear cell carcinoma (CC). Mucinous epithelial tumors were multilocular in 23 of 24 tumors, while signal intensityof the locules varied in 22 of 24. Six of 16 serous epithelial tumors were unilocular, and 15 of 16 were ofhomogeneous signal intensity. Papillary projection was seen in 14 tumors (SB 1/3, SBM 5/5, SM 3/8, MB 2/11, MBM2/9, CC 1/1), but multiple (>10) projections were seen in SBM (5/5) and CC (1/1). Multiple irregular thick septawere found in 18 tumors (SM 3/8, MB 2/11, MBM 9/9, MM 4/4), while solid components were seen in ten (SM 6/8, MB1/11, MM 2/4, EC 1/1). CONCLUSION: Multiple (>10) papillary projections and multiple irregular thick septa withoutremarkable solid components are suggestive MR findings of ovarian SBM and MBM, respectively.

Whirling Sign: An Imaging Finding Indicating Ovarian Torsion

PURPOSE: To present a diagnostic sign on MRI and US in patients with ovarian torsion. MATERIALS AND METHODS: We present characteristic imaging findings in eight patients with surgically-proven ovarian torsion. MRI was performed in four patients, CT in six and US in all patients; the procedures including eight transabdominal US(TAS) and three transvaginal US(TVS). In each study, imaging findings were analyzed for the appearance of twisted pedicle and the presence of a "whirling sign". RESULTS: The pedicle which indicates ovarian torsion was detected on MRI in all 4 patients, on TAS in 4/7, on TVS in 3/3, and on CT in 4/6. A specific "whirling sign" was detected on MRI in 2/4 patients, on TAS in 2/4, and on TVS in all three. On CT a "whirling sign" was not detected. CONCLUSION: The "whirling sign" on both MRI & US is a characteristic finding of ovarian torsion; in a patient with adnexal mass and complaining of lower abdominal pain, the presence of this sign is very useful for the diagnosis of ovarian torsion.

Whirling Sign: An Imaging Finding Indicating Ovarian Torsion

PURPOSE: To present a diagnostic sign on MRI and US in patients with ovarian torsion. MATERIALS AND METHODS: We present characteristic imaging findings in eight patients with surgically-proven ovarian torsion. MRI was performed in four patients, CT in six and US in all patients; the procedures including eight transabdominal US(TAS) and three transvaginal US(TVS). In each study, imaging findings were analyzed for the appearance of twisted pedicle and the presence of a "whirling sign". RESULTS: The pedicle which indicates ovarian torsion was detected on MRI in all 4 patients, on TAS in 4/7, on TVS in 3/3, and on CT in 4/6. A specific "whirling sign" was detected on MRI in 2/4 patients, on TAS in 2/4, and on TVS in all three. On CT a "whirling sign" was not detected. CONCLUSION: The "whirling sign" on both MRI & US is a characteristic finding of ovarian torsion; in a patient with adnexal mass and complaining of lower abdominal pain, the presence of this sign is very useful for the diagnosis of ovarian torsion.