Ovarian Brenner tumors: MR imaging characteristics

Magnetic resonance imaging findings of cystic ovarian tumors: major differential diagnoses in five types frequently encountered in daily clinical practice

There are many types of ovarian tumors, and these different types often form cystic masses with a similar appearance, which can make their differentiation difficult. However, with the exclusion of rare ovarian tumors, the number of ovarian tumors encountered in daily practice is somewhat fixed. It goes without saying that magnetic resonance imaging (MRI) is useful for differentiating ovarian tumors. In this review, we summarize the differential diagnoses for each of the five types of MRI findings commonly encountered in daily practice. First, unilocular cystic masses without mural nodules/solid components include benign lesions such as serous cystadenoma, functional cysts, surface epithelial inclusion cysts, paratubal cysts, and endometriosis. Second, multilocular cystic ovarian lesions include mucinous tumors and ovarian metastases. It should be noted that mucinous tumors may be diagnosed as borderline or carcinoma, even if no solid component is observed. Third, cystic lesions with mural nodules that are unrelated to endometriosis include serous borderline tumor and serous carcinoma. Cystic lesions with solid components are more likely to be malignant, but some may be diagnosed as benign. Fourth, ovarian tumors deriving from endometriosis include seromucinous borderline tumors, endometrioid carcinoma, and clear cell carcinoma. These tumors sometimes need to be differentiated from serous tumors. Finally, cystic lesions with lipid contents include teratoma-related tumors. In mature cystic teratoma, mural nodules (called "Rokitansky protuberance" or "dermoid nipple") are sometimes seen, but they do not suggest malignancy. Some of these lesions can be diagnosed accurately by considering their characteristic imaging findings, their changes over time, MRI findings other than those of the primary lesion, and information from other modalities such as tumor markers. To ensure the optimal treatment for ovarian tumors, it is important to estimate the histological type as well as to diagnose whether a lesion is benign or malignant.

Benign Brenner tumour of the ovary: CT and MRI features

AIM

To evaluate the computed tomography (CT) and magnetic resonance imaging (MRI) features of benign Brenner tumours (BBT) of the ovary.

MATERIAL AND METHODS

This was a retrospective two-centre study comprising 35 female patients with a definitive diagnosis of BBT at histology in whom CT and/or MRI examinations had been performed. Two experienced radiologists reviewed the CT and MRI features of 39 ovarian BBT retrospectively with consensus reading. The morphological appearance and size of each tumour were recorded. The presence or absence of calcifications within the solid portion was noted at CT. The reviewed characteristics at MRI included qualitative assessment of the signal intensity of the solid portion on diffusion sequence and contrast enhancement, compared to that of the myometrium.

RESULTS

CT and MRI images were available for 27 and 28 lesions, respectively. Sixteen patients had both CT and MRI examinations. BBT were unilateral in 89% of patients, and 49% of lesions were solid and 51% were mixed. Calcifications were depicted at CT in 70.4% of lesions. When present, the cystic portion was multilocular in 85% of cases and corresponded to a mucinous lesion in 74% of cases. Enhancement of the solid portion at MRI was inferior or equal to that of the myometrium in 89% of cases and signal on high b-values diffusion images was deemed low or moderate in 93% of cases.

CONCLUSION

The combined CT and MRI findings of a unilateral fibrous ovarian mass containing punctate calcifications often associated with a multilocular cyst suggest the diagnosis of ovarian BBT.

Adnexal masses characterized on 3 tesla magnetic resonance imaging - added value of diffusion techniques

Background

To assess different types of adnexal masses as identified by 3T MRI and to discuss the added value of diffusion techniques compared with conventional sequences.

Patients and methods

174 women age between 13 and 87 underwent an MRI examination of the pelvis for a period of three years. Patients were examined in two radiology departments – 135 of them on 3 Tesla MRI Siemens Verio and 39 on 3 Tesla MRI Philips Ingenia. At least one adnexal mass was diagnosed in 98 patients and they are subject to this study. Some of them were reviewed retrospectively. Data from patients’ history, physical examination and laboratory tests were reviewed as well.

Results

124 ovarian masses in 98 females’ group of average age 47.2 years were detected. Following the MRI criteria, 59.2% of the cases were considered benign, 30.6% malignant and 10.2% borderline. Out of all masses 58.1% were classified as cystic, 12.9% as solid and 29% as mixed. Оf histologically proven tumors 74.4% were benign and 25.6% were malignant. All of the malignant tumors had restricted diffusion. 64 out of all patients underwent contrast enhancement. (34 there were a subject of contraindications). 39 (61%) of the masses showed contrast enhancement.

Conclusions

Classifying adnexal masses is essential for the preoperative management of the patients. 3T MRI protocols, in particular diffusion techniques, increase significantly the accuracy of the diagnostic assessment.

MRI and FDG PET/CT Findings for Borderline Brenner Tumor of the Ovary: A Case Report and Literature Review

The imaging features of borderline Brenner tumor (BT) of the ovary are very limited, especially regarding apparent diffusion coefficient (ADC) value and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET)/CT. We report a case of borderline BT in a 54-year-old woman with diffusion-weighted imaging (DWI) and FDG-PET/CT findings. Furthermore, ADC values and maximum standardized uptake value (SUV max) in the present case were compared with those of an additional 7 cases of benign BT in this institution in addition to literature reviews. Magnetic resonance imaging (MRI) revealed a pelvic unilocular cystic tumor with two solid components. The solid mass showing a low signal intensity (SI) in T2-weighted images (T2WI) and DWI was diagnosed as a benign BT histologically. The papillary tumor adjacent to the solid mass showing intermediate SI in T2WIs and high SI on DWI was a borderline BT. The mean ADC value (×10⁻³ mm²/s) of benign BTs (n = 7) and benign component in this case (n = 1) was 1.13, and the range of ADC values was broad (0.51–1.8). While, the ADC value of borderline Brenner component in this case was 1.10. The mean SUVmax of the benign BTs (n = 4) demonstrated mild FDG uptakes (2.3, range 1.9–2.6) in contrast with moderate FDG uptake (SUVmax: 5.8) of borderline Brenner component in this case and high FDG uptake (SUVmax: 9.6) of a malignant BT in a previous report. ADC values for the solid component of BTs are not useful for differentiating benign from malignant or borderline components, whereas PET/CT could be useful.

Ovarian solid tumors: MR imaging features with radiologic-pathologic correlation

Ovarian solid tumors have variable histological types including benign and malignant tumors. In addition, non-neoplastic lesions sometimes show a tumor-like appearance. It is important to differentiate benign from malignant tumors. In general, low signal intensity (SI) on T2-weighted imaging (T2WI), low SI on diffusion-weighted imaging (DWI), and gradual increased pattern on dynamic contrast-enhanced magnetic resonance (MR) imaging are known to be suggestive of a benign tumor. Conversely, there are some cases in which these rules do not apply. We should, therefore, strive for a greater understanding of these exceptional cases. Several tumors show characteristic findings on MR imaging reflecting pathologic features, which leads to the correct diagnosis. Additionally, MR imaging provides important information other than the nature of tumors, such as secondary uterine changes. Furthermore, clinical findings and laboratory examination data also help in determining the correct diagnosis.

Primary ovarian leiomyoma with predominant cystic change

Ovarian leiomyoma is a rare benign tumor, seen mostly in women 20-65 years old. The case of a 51-year-old woman with a large tumor in the pelvic cavity is reported. The dominant feature of the tumor was its cystic component, but an irregular, solid component was recognized along the dorsal margin of the tumor. The latter area showed signal intensity as low as muscle on T2-weighted images and significant contrast enhancement; however, it did not show restricted diffusion, which implied that it was benign. The large tumor was resected because malignancy could not be ruled out, and it was pathologically diagnosed as ovarian leiomyoma with predominant necrosis. When a low-intensity component without malignant features is seen on magnetic resonance imaging, leiomyoma should be included in the differential diagnosis despite its rare occurrence in the ovary.

Computed tomography and magnetic resonance imaging features of ovarian fibrothecoma

The aim of the present study was to investigate the imaging characteristics of ovarian fibrothecoma. The cases of 25 female patients with pathologically confirmed ovarian fibrothecomas were retrospectively reviewed. Tumor location, size, density, signal intensity, cystic degeneration, calcification, enhancement pattern and ascites were assessed by computed tomography (CT) (n=20) and magnetic resonance imaging (MRI) (n=5). Clinical and histological features were also evaluated. The results revealed that 23 (92.0%) patients were postmenopausal, with a mean age ± standard deviation (SD) of 60.7±10.8 years old. All 25 tumors were unilateral and a thickened endometrium was observed in 7 (28.0%) patients. In total, 24 (96.0%) tumors appeared to have well-defined boundaries, with 1 (4%) tumor exhibiting an obscure boundary. Tumors had a mean size of 9.8±5.3 cm. Solid and predominantly solid masses were found in 16 cases (64.0%), and cystic and predominantly cystic masses were found in 9 patients (36.0%). Solid regions of masses exhibited hypodensity or isodensity in 24 patients (96.0%), with 1 patient (4.0%) exhibiting hyperdensity. The mean CT value (± SD) was 44.2±12.8 HU (range, 31-79HU) in unenhanced images. All masses exhibited isointensity or slight hypointensity on T1-weighted imaging, and tumor parenchyma also exhibited slight hypointensity or isointensity on T2-weighted imaging compared with the myometrium, with or without areas of patchy hyperintensity. Contrast-enhanced CT or MRI scans were performed on 19 patients, and the solid components (94.7%) exhibited mild to moderate enhancement in 18 patients and 1 patient (5.3%) exhibited intense enhancement. Tumor size was positively correlated with the tumor cystic degeneration (r=0.77, P<0.001) and ascites (r=0.41, P<0.001). Therefore, ovarian fibrothecoma typically presents as solid or predominant solid masses with clear boundaries; the parenchyma of the tumor exhibits isodensity on CT scans, slight hypointensity or isointensity on MRI and mild enhancement following contrast-medium injection. The thickened endometrium observed in postmenopausal woman may also be a valuable imaging feature.

Ovarian mucinous cystadenoma coexisting with benign Brenner tumor: MR imaging findings

PURPOSE

The purpose of this study was to describe the MR imaging findings of ovarian mucinous cystadenomas coexisting with benign Brenner tumors.

MATERIALS AND METHODS

MR images with a 1.5-T unit obtained in five consecutive patients (age range, 51-72 years; mean age, 61 years) with surgically confirmed ovarian mucinous cystadenomas coexisting with benign Brenner tumors were retrospectively reviewed for the presence, configuration, and signal intensity of cystic and solid components of the lesions.

RESULTS

Tumors ranged in size from 7.5 to 22.1 cm (mean, 13.5 cm). In four patients (80%), the size of mucinous cystadenoma (range 6.4-22.1 cm; mean, 12.5 cm) was larger than that of Brenner tumor (range 0.2-9.1 cm; mean, 2.8 cm). All patients (100%) had cystic, and three (60%) had solid components. Four patients (80%) showed multilocular cystic, and one (20%) showed unilocular cystic appearance. MR imaging findings were classified into three patterns: (1) a bulky solid mass adjacent to the cystic component, (2) a mural nodule at the periphery of the cystic component, and (3) a cystic component without a detectable solid component. All four multilocular cystic areas exhibited "stained glass" appearances on both T1- and T2-weighted images, and all three solid areas showed homogeneous hypointensity on T2-weighted images.

CONCLUSION

Mucinous cystadenomas were often larger than the coexisting benign Brenner tumors. Mucinous cystadenomas coexisting with benign Brenner tumors should be considered when multilocular or unilocular cystic components are accompanied by homogeneously hypointense solid components on T2-weighted images.

Diffusion-weighted imaging of a malignant brenner tumor

Microscopically, ovarian malignant Brenner tumor shows components of malignant transitional cell tumor intermixed with benign and borderline elements. We report a case of this tumor with components that transition from benign to malignant on diffusion-weighted images (DWI) and in histologic findings. The benign component showed low signal intensity on T(2)-weighted images, whereas the malignant component showed high signal intensity on T(2)-weighted images and high signal intensity on DWI with low apparent diffusion coefficient (ADC) value.

The MRI features of histologically proven ovarian cystadenofibromas-an assessment of the morphological and enhancement patterns

OBJECTIVES

To assess the morphological and enhancement features of histologically proven cystadenofibromas (CAFs) on magnetic resonance imaging (MRI).

METHODS

Forty-seven histologically proven CAFs (42 benign, five borderline) were retrospectively reviewed. One benign CAF had a synchronous adenocarcinoma in the same ovary. The morphological, signal and enhancement characteristics on MRI were recorded.

RESULTS

The mean long axis diameter of the CAFs was 80 mm. The contralateral ovary was abnormal in 45 % of cases. A solid component was seen in 85 %, which returned low T2-weighted signal in 75 % of CAFs. Septa were seen in 74 % and one CAF was purely cystic. The majority of solid components and septa demonstrated enhancement that was less than the myometrium. Wash-in rates (WIR) of the solid tissue were available for measurement in nine patients with an average WIR of 3.2 l/s.

CONCLUSION

This is the largest series describing MRI appearances of histologically proven CAFs. They are typically complex adnexal lesions containing septa, cystic components and solid tissue. The majority of solid components demonstrate low T2 signal and minimal enhancement. Almost half of the cases have an abnormal contralateral ovary.

Magnetic resonance histology of age-related nephropathy in the Sprague Dawley rat

Magnetic resonance histology (MRH) has become a valuable tool in evaluating drug-induced toxicity in preclinical models. However, its application in renal injury has been limited. This study tested the hypothesis that MRH could detect image-based biomarkers of chronic disease, inflammation, or age-related degeneration in the kidney, laying the foundation for more extensive use in evaluating drug toxicity. We examined the entire intact kidney in a spontaneous model of chronic progressive nephropathy. Kidneys from male Sprague Dawley rats were imaged at 8 weeks (n = 4) and 52 weeks (n =4) on a 9.4 T system dedicated to MR microscopy. Several potential contrast mechanisms were explored to optimize the scanning protocols. Full coverage of the entire kidney was achieved with isotropic spatial resolution at 31 microns (voxel volume = 30 pL) using a gradient recalled echo sequence. Isotropic spatial resolution of 15 microns (voxel volume < 4 pL) was achieved in a biopsy core specimen. Qualitative age-related structural changes, such as renal cortical microvasculature, tubular dilation, interstitial fibrosis, and glomerular architecture, were apparent. The nondestructive 3D images allowed measurement of quantitative differences of kidney volume, pelvis volume, main vessel volume, glomerular size, as well as thickness of the cortex, outer medulla, and inner medulla.

Targeted molecular imaging of antigen OC183B2 in ovarian cancers using MR molecular probes

RATIONALE AND OBJECTIVES

This study was designed to develop a novel magnetic resonance (MR) probe for the antigen OC183B2 in ovarian cancer cells and investigate its imaging features in vitro and in vivo.

MATERIALS AND METHODS

Molecular probes were achieved through ultrasmall superparamagnetic iron oxide nanoparticles (USPIOs) conjugated to ovarian cancer monoclonal antibodies 183B2 (OCMab183B2) using a chemical method. In the control group, USPIOs were coupled with murine immunoglobulin G (mIgG) and conjugated the same way. Native polyacrylamide gel electrophoresis was used to evaluate the conjugation reaction. The cytotoxicity of the probe was measured using the methyl thiazolyl tetrazolium assay, and its cell-labeling efficiency was evaluated by Prussian blue staining. In vitro cell MR imaging was performed to evaluate the targeting of the probe to the cells. After that, the OCMab183B2 USPIOs and mIgG USPIOs were injected intravenously into nude mice implanted with ovarian cancer xenograft tumors, respectively. T2-weighted imaging and T2 mapping were then performed on a 3.0-T MR imaging system equipped with an animal birdcage coil at different times. Finally, the nude mice were sacrificed for histologic examination to confirm the imaging results.

RESULTS

Native polyacrylamide gel electrophoresis displayed an optimal conjugation of USPIOs to OCMab183B2 and mIgG. Various blue-staining particles were found in the cells labeled with the molecular probe at different iron concentrations, and the density of particles was positively related to the iron concentration. Its labeling rate was 96.06%, which was higher than that of USPIOs (62.5%) at the same iron concentration (20 μg/mL). The methyl thiazolyl tetrazolium assay showed that there was no difference in cellular bioactivity between OCMab183B2 USPIO-labeled and nonlabeled cells (P > .05). In vitro cell MR imaging showed that there was an obvious decrease in signal intensity for the probe-labeled cells compared to mIgG USPIO-labeled cells. For in vivo MR imaging, distinct changes of signal intensities and T2 values of ovarian cancers were detected after the injection of OCMab183B2 USPIOs compared to mIgG USPIOs. The histologic analysis showed that iron depositions were visualized in the experimental group but not in the control group.

CONCLUSION

OCMab183B2 USPIO conjugates have the potential to be useful as OC183B2-targeted MR imaging agents for the early detection of ovarian cancers.

[Uterine leiomyoma]

Uterine fibroids, benign tumors of the human uterus, are the most common indication for hysterectomy. They are clinically apparent in 20-25% of women and cause significant complaints, like prolonged and heavy menstruation, pelvic pressure or pain, sometimes reproductive dysfunction. Though surgery has been the mainstay of fibroid treatment, various minimally invasive procedures have been developed in addition to hysterectomy and abdominal myomectomy. Formation of new leiomyomas after these conservative therapies remains a substantial problem. Also drug-therapy methods are available, but the possible side-effects limit their long-term use. Authors attempt to give an overview of this common gynecological disease, yielding a new insight into the basic biology and genetics of fibroids, with the hope of new and effective methods of therapy in the future.

Diffusion-weighted magnetic resonance imaging of ovarian tumors: differentiation of benign and malignant solid components of ovarian masses

OBJECTIVE

We evaluated the feasibility of diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) measurement in differentiating benign and malignant ovarian tumors.

METHODS

Surgically proven 49 ovarian tumors (39 malignant/borderline malignant and 10 benign) were examined.

RESULTS

The solid portion of all 39 malignant tumors showed homogeneous or heterogeneous high intensity on DWI, whereas only 3 of the 10 benign tumors (3 thecomas) showed high intensity. The mean (SD) ADC value in the 39 malignant tumors (1.03 [0.19]) was significantly lower than that in 10 benign tumors (1.38 [0.30]). A relatively low ADC (1.08-1.20) in the 3 thecomas may reflect their abundant cellular nature, and the presence of low intensity on T2-weighted images was suggestive for benign fibrous tumor.

CONCLUSIONS

Low intensity on DWI with high ADC may suggest benign lesions; however, it may be occasionally difficult to differentiate benign and malignant lesions only on the basis of DWI.

Transitional cell tumor of the ovary: computed tomographic and magnetic resonance imaging features with pathological correlation

OBJECTIVE

To describe computed tomographic (CT) and magnetic resonance (MR) imaging findings of transitional cell tumors, including newly established transitional cell carcinoma, according to tumor type with pathological correlation.

METHODS

We retrospectively reviewed the CT and MR images of 22 patients with transitional cell tumors of ovary (14 benign Brenner, 2 borderline Brenner, 2 malignant Brenner, and 4 transitional cell carcinomas) for the following factors: size, location, configuration, signal intensity, staging, and accompanying ovarian tumors.

RESULTS

Sixteen tumors were detected on CT or MRI (8 benign, 2 borderline, and 6 malignant tumors), and the mean size of measurable tumors was 8.8 cm. Benign Brenner tumors were homogeneous solid (n = 6) or unilocular cystic (n = 2). Two borderline Brenner tumors were multilocular cystic. Malignant tumors, including malignant Brenner tumors and transitional cell carcinomas, were heterogeneous solid (n = 3) or multilocular cystic (n = 3). The signal intensity of solid components on T2-weighted images was isointense compared with that of muscle in benign and borderline Brenner tumors and hyperintense in malignant tumors.

CONCLUSIONS

The CT and MR appearance of transitional cell tumors varied according to tumor type. Benign Brenner tumors were homogeneous solid or unilocular cystic pattern, and malignant tumors were heterogeneous solid or multilocular cystic.

Dynamic contrast-enhanced MR imaging of ovarian neoplasms: current status and future perspectives

MR imaging is useful for characterizing ovarian tumors. Dynamic contrast-enhanced MR imaging is a promising new technique useful for characterizing perfusion and angiogenesis of ovarian masses. This article describes the dynamic contrast-enhanced MR imaging technique examines the current and future applications of this technique in patients with ovarian tumors.

Value of magnetic resonance imaging for the diagnosis of ovarian tumors: a review

This article reviews the value of magnetic resonance imaging (MRI) for the diagnosis of ovarian tumors especially when ultrasonography is indeterminate. Although ultrasonography is the first imaging technique used to investigate suspected pelvic masses, it has a limited capacity for tissue characterization. In addition to morphological characteristics, many tissue parameters such as T1, T2, perfusion, and diffusion contribute to signal intensity, so MRI is able to identify various types of tissue contained in pelvic masses. Magnetic resonance imaging helps to locate large solid masses and to distinguish benign from malignant ovarian tumors, with an overall accuracy of 88% to 93% for the diagnosis of malignancy. The aims of this review are 3-fold. First, we review state-of-the-art and usual MRI techniques and published findings. Second, we recall the MR features most useful for assessing the main ovarian tumors. Finally, we discuss the relevance of various features for distinguishing between benign, borderline, and invasive ovarian tumors.

Aspects of an ovarian osteoma on magnetic resonance imaging and computerized tomography

OBJECTIVE

To describe the contribution of magnetic resonance imaging (MRI) and computerized tomography (CT) scan to the diagnosis of an ovarian osteoma.

DESIGN

Descriptive case study.

SETTING

Tertiary care center, Hôpital Tenon, Assistance Publique des Hôpitaux de Paris, University Pierre et Marie Curie, Paris, France.

PATIENT(S)

A 29-year-old woman with a left-sided calcified ovarian tumor on MRI and CT scan, suggesting an ovarian osteoma.

INTERVENTION(S)

Surgical removal of a 64-mm primary ovarian osteoma, exclusively by the vaginal route.

MAIN OUTCOME MEASURE(S)

The MRI and CT scan findings.

RESULT(S)

Histologic examination showed an ovarian osteoma characterized by mature bone tissue, with no signs of malignancy.

CONCLUSION(S)

Ovarian osteoma can be adequately diagnosed by MRI or CT scan and can be treated conservatively.

Magnetic resonance imaging of adnexal masses

Adnexal masses are common in women of all ages. A range of physiological and benign ovarian conditions that develop in women, especially in the reproductive age, and adnexal malignancies can be evaluated with magnetic resonance imaging (MRI). Management of women with adnexal masses is frequently guided by imaging findings; therefore, precise characterization of adnexal pathology should be performed whenever possible. Magnetic resonance imaging is useful in characterization of adnexal masses that are not completely evaluated by ultrasound because it can provide additional information on soft tissue composition of adnexal masses based on specific tissue relaxation times and allows multiplanar imaging at large field of view to define the origin and extent of pelvic pathology. The patients most likely to benefit from MRI are pregnant women and those who are premenopausal and have masses that have complex features on ultrasound but do not have raised cancer antigen 125 tumor marker levels. The overlap in imaging appearance among different cell type malignancies makes it difficult to predict exact histology based on MRI appearance; however, MRI has a high accuracy in differentiating benign from malignant masses. Teratomas, endometriomas, simple and hemorrhagic cysts, fibromas, exophytic or extrauterine fibroids, and hydrosalpinges can be diagnosed with high confidence. In this article, the authors review the histopathologic background and MRI features of adnexal masses and discuss the role of MRI in the differentiation of benign from malignant adnexal pathologies.

MR imaging evaluation of the adnexa

MR imaging has become an important tool in the evaluation of patients with adnexal disease, and its role continues to evolve. Some benign entities can be diagnosed by MR imaging with a high grade of confidence, such as teratomas, endometriomas, simple and hemorrhagic cysts, fibromas, and hydrosalpinx. In cases of malignant lesions, MR imaging may be more accurate than other modalities for lesion characterization, staging, and follow-up.

Developing an MR imaging strategy for diagnosis of ovarian masses

Magnetic resonance (MR) imaging provides useful information for characterization of various ovarian masses as neoplastic or nonneoplastic and, when neoplastic, on a spectrum from benign to malignant. The use of MR imaging for diagnosis of ovarian masses includes consideration of morphologic characteristics and signal intensity characteristics on T1- and T2-weighted images. The morphologic characteristics of cystic masses, cystic and solid masses, and predominantly solid masses provide important information. In general, cystic masses represent benign tumors, whereas cystic and solid masses are strongly associated with malignancy. Predominantly solid masses include benign, borderline malignant, and malignant tumors. T1-weighted images provide useful information for characterization because hemorrhagic adnexal masses (eg, endometriotic cyst) and cystic teratomas can be correctly diagnosed when the mass has high signal intensity. Significant low signal intensity in solid masses on T2-weighted images is indicative of fibrothecomas and Brenner tumors because extensive fibrous tissue produces significant low signal intensity on T2-weighted images. A strategy for diagnosis of ovarian masses with MR imaging incorporates signal intensity characteristics into morphologic characteristics.

MRI of sonographically indeterminate adnexal masses

OBJECTIVE

The purpose of this study was to assess the ability of MRI to characterize sonographically indeterminate adnexal masses and to define the sonographic features contributing to indeterminate diagnoses.

MATERIALS AND METHODS

Two blinded radiologists retrospectively reviewed the MRI examinations of 87 patients with 95 sonographically indeterminate adnexal masses. Reviewers determined the origin of a mass, its tissue content (cystic, solid, complex cystic, or cystic and solid), tissue characteristics (fat, blood, fibrous, or leiomyomatous), and benignity versus malignancy. Sonograms were reviewed by three reviewers to determine the origin of a mass, its tissue content, and reasons for an indeterminate diagnosis. Sensitivity and specificity of MRI were calculated, and agreement of sonography and MRI with the final diagnosis was determined using kappa statistics. The final diagnosis was determined by histopathology, surgical findings, or imaging or clinical follow-up.

RESULTS

The sensitivity of MRI for identifying malignancy (n = 5) was 100% and its specificity for benignity (n = 90) was 94%. Excellent agreement was seen between MRI and the final diagnosis for determining the origin (kappa = 0.93), tissue content (kappa = 0.98), and tissue characteristics (kappa = 0.91) of a mass. Sonography had poor agreement with the final diagnosis for the origin (kappa = 0.19) and tissue content (kappa = 0.33) of a mass. The main reasons for indeterminate sonographic diagnoses were the inability to determine origin because of location and large mass size and the appearances of purely solid or complex cystic masses.

CONCLUSION

Sonographically indeterminate adnexal masses of uncertain origin and solid or complex cystic content benefit from further evaluation with MRI, which is highly accurate for identifying the origin of a mass and characterizing its tissue content, obviating surgery.

MR features of physiologic and benign conditions of the ovary

In reproductive women, various physiologic conditions can cause morphologic changes of the ovary, resembling pathologic conditions. Benign ovarian diseases can also simulate malignancies. Magnetic resonance imaging (MRI) can play an important role in establishing accurate diagnosis. Functional cysts should not be confused with cystic neoplasms. Corpus luteum cysts typically have a thick wall and are occasionally hemorrhagic. Multicystic lesions that may mimic cystic neoplasms include hyperreactio luteinalis, ovarian hyperstimulation syndrome, and polycystic ovary syndrome. Recognition of clinical settings can help establish diagnosis. In endometrial cysts, MRI usually provides specific diagnosis; however, decidual change during pregnancy should not be confused with secondary neoplasm. Peritoneal inclusion cysts can be distinguished from cystic neoplasms by recognition of their characteristic configurations. Ovarian torsion and massive ovarian edema may mimic solid malignant tumors. Recognition of normal follicles and anatomic structures is useful in diagnosing these conditions. In pelvic inflammatory diseases, transfascial spread of the lesion should not be confused with invasive malignant tumors. Radiologic identification of abscess formation can be a diagnostic clue. Many benign tumors, including teratoma, Brenner tumor, and sex-cord stromal tumor, frequently show characteristic MRI features. Knowledge of MRI features of these conditions is essential in establishing accurate diagnosis and determining appropriate treatment.

MDCT of the Gonadal Veins in Females with Large Pelvic Masses: Value in Differentiating Ovarian Versus Uterine Origin

OBJECTIVE

The objective of our study was to determine the usefulness of recognizing the continuity of the gonadal veins to the pelvic mass to differentiate ovarian versus uterine origin on MDCT in females with a large pelvic mass.

MATERIALS AND METHODS

Two radiologists interpreted the MDCT images obtained on a monitor, using paging methods, in 86 female patients with a large pelvic mass (> 8 cm) and 40 patients without an abdominopelvic mass as control subjects. The following issues were recorded using a 5-point scale: visualization of gonadal veins and origin determination based on anatomic continuity. Receiver operating characteristic (ROC) curve analysis was performed, and the interobserver differences were checked with kappa statistics. The maximum diameters of the gonadal veins were also measured. With consensus interpretations, the sensitivity, specificity, and accuracy of ovarian origin determination were calculated.

RESULTS

Gonadal veins were shown in more than 70% of the subjects in both the control group and the patients with a mass (hereafter referred to as the "mass group"). There was no significant difference in the diameter of the gonadal veins between the control and mass groups and between patients with an ovarian mass and those with a uterine mass. The values for the area under the ROC curve (A(z)) of the two observers for ovarian origin determination were 0.90 and 0.92. The kappa value was 0.48. The sensitivity, specificity, and accuracy were 83.3%, 87.5%, and 84.9%, respectively.

CONCLUSION

Gonadal veins can be shown on MDCT with high consistency; MDCT provides useful information for determining the origin of relatively large pelvic tumors arising in females.

Interleaved acquisition of lipid and water images of the heart using a double-inversion fast spin-echo method

In this work we present a new method for the improved detection of lipid infiltration in the heart. The method employs a double-inversion fast spin-echo technique where the acquisition of water- and lipid-suppressed k-space data is alternated between TR periods to produce co-registered lipid and water images from data acquired in a breath hold. The lipid and water images can then be combined to generate a lipid/water image with reduced artifacts due to flow and excellent contrast between lipid and myocardium. The method is demonstrated in ex vivo tissue and in vivo. This novel method may improve the detection of lipid infiltration in the heart in pathologies such as arrhythmogenic right ventricular dysplasia.

Ovarian cancer: the clinical role of US, CT, and MRI

This article presents an overview of ovarian cancer, which addresses the clinical roles of imaging studies, including US, CT, and MR imaging in the course of diagnosis and treatment of this important disease. US is the modality of choice in the evaluation of patients with suspected adnexal masses. Although its accuracy is not sufficient to avert surgery, morphological analysis of adnexal masses with US helps narrow the differential diagnosis, determining the degree of suspicion for malignancy, usually in concert with a serum CA-125 level. Combined morphological and vascular imaging obtained by US appear to further improve the preoperative assessment of adnexal masses. For uncertain or problematic cases, MR imaging helps to distinguish benign from malignant, with an overall accuracy for the diagnosis of malignancy of 93%. The accuracy of MR imaging in the confident diagnosis of mature cystic teratoma, endometrial cysts, and leiomayomas is very high. CT is not indicated for differential diagnosis of adnexal masses because of poor soft tissue discrimination, except for fatty tissue and for calcification, and the disadvantages of irradiation. In the staging of ovarian cancer, CT, US, and MR imaging all have a similarly high accuracy. Although it is difficult to suggest a simple algorithm for evaluating the state of women with adnexal masses, the correct preoperative diagnosis and staging of ovarian cancer with the use of any of these imaging studies will lead to an appropriate referral to a specialist in gynecologic oncology and offer a significant survival advantage for patients with ovarian cancer.

"Ovarian vascular pedicle" sign revealing organ of origin of a pelvic mass lesion on helical CT

OBJECTIVE

We evaluated the "ovarian vascular pedicle" sign as a way of differentiating ovarian from subserosal uterine lesions on single-detector helical CT.

SUBJECTS AND METHODS

We prospectively evaluated 131 patients who had a pelvic mass suspected of originating in the ovary or subserosal zone of the uterus and had undergone helical CT before surgery. A total of 108 ovarian lesions and 23 subserosal uterine myomas were confirmed. CT images were analyzed prospectively by consensus of two radiologists who thoroughly evaluated the retrograde tracing of the gonadal veins to the ovary or pelvic mass. To assess the value of analyzing the ovarian vascular pedicle sign in identifying the organ of origin of a pelvic mass, we compared statistical proportions for the frequencies of the sign in ovarian tumors and subserosal uterine myomas by performing the chi-square test. The probabilities for the presence of the ovarian vascular pedicle sign as a positive finding for a pelvic mass of ovarian origin were calculated.

RESULTS

The presence of the ovarian vascular pedicle sign was identified in 92% (99/108) of ovarian masses and in 13% (3/23) of subserosal uterine myomas. The sign was statistically significant (p < 0.01) for differentiating a mass of ovarian origin from a mass of subserosal uterine origin. When the ovarian vascular pedicle sign on helical CT confirmed the ovarian origin, the sensitivity, specificity, positive predictive value and negative predictive value, and diagnostic accuracy were 92% (99/108), 87% (20/23), 97% (99/102), 69% (20/29), and 91% (119/131), respectively.

CONCLUSION

The presence of the ovarian vascular pedicle sign on helical CT is valuable for confirming the ovarian origin of a pelvic tumor and for differentiating an ovarian tumor from subserosal uterine myoma.

MR imaging of the ovaries: normal appearance and benign disease

MR imaging enables a physician to make an accurate diagnosis of various benign adnexal masses and helps to obviate unnecessary surgery.

Characterization of adnexal mass lesions on MR imaging

OBJECTIVE

The aim of our study was to evaluate the accuracy of MR imaging in the detection and characterization of adnexal mass lesions and to determine which imaging features are predictive of malignancy.

SUBJECTS AND METHODS

We prospectively performed MR imaging in 104 patients (age range, 19-87 years; mean age, 50 years) with clinically or sonographically detected complex adnexal masses. We used a 1.5-T unit to perform T1-, T2-, and fat-suppressed T1-weighted sequences before and after IV injection of gadolinium. The adnexal lesions were examined for several features including size, shape, character (solid-cystic), vegetation, signal intensity, and enhancement. Secondary signs such as ascites, peritoneal disease, and lymphadenopathy were noted. We compared the imaging features with the surgical and pathologic findings. Multiple logistic regression analysis was performed on all MR imaging features.

RESULTS

A total of 163 lesions--94 benign and 69 malignant lesions--were examined. On MR imaging, 95% (155/163) of the lesions were detected. The overall accuracy for the diagnosis of malignancy was 91%. On univariate analysis, the imaging features associated with malignancy were a solid-cystic lesion, irregularity, and vegetation on the wall and septum in a cystic lesion, the large size of the lesion, an early enhancement on dynamic contrast-enhanced MR images, and the presence of ascites, peritoneal disease, or adenopathy. On multiple logistic regression analysis, ascites and vegetation in a cystic lesion were the factors most significantly indicative of malignancy.

CONCLUSION

MR imaging is highly accurate in the characterization of adnexal mass lesions, and the best predictors of malignancy are vegetation in a cystic lesion and ascites.

CT and MR imaging of ovarian tumors with emphasis on differential diagnosis

Ovarian tumors are classified on the basis of tumor origin as epithelial tumors (serous and mucinous tumors, endometrioid and clear cell carcinomas, Brenner tumor), germ cell tumors (mature and immature teratomas, dysgerminoma, endodermal sinus tumor, embryonal carcinoma), sex cord-stromal tumors (fibrothecoma; granulosa cell, sclerosing stromal, and Sertoli-Leydig cell tumors), and metastatic tumors. Epithelial tumors are primarily cystic and, when malignant, are associated with varying proportions of a solid component. Papillary projections are a distinctive feature of epithelial tumors. Profuse papillary projections are highly suggestive of borderline (low-malignant-potential) or malignant tumor. Ovarian teratomas demonstrate lipid material at computed tomography and magnetic resonance (MR) imaging. Malignant germ cell tumors manifest as a large, complex abdominal mass that contains both solid and cystic components. Tumor markers are helpful in diagnosis. The radiologic appearance of sex cord-stromal tumors varies from small solid masses to large multicystic masses. Granulosa cell tumors are usually large multicystic masses with solid components. Fibrothecoma, sclerosing stromal tumor, and Sertoli-Leydig cell tumors are usually solid masses. Fibromas have very low signal intensity on T2-weighted MR images. Certain radiologic findings predominate for each type of tumor. Knowledge of these key features of ovarian tumors provides the criteria for making a specific diagnosis or substantially narrowing the differential diagnosis.

Magnetic resonance imaging of the ovary

Magnetic resonance imaging (MRI) of the pelvis can characterize a wide variety of ovarian lesions. We discuss MRI strategies for identification and characterization of ovarian neoplasms and correlate MRI findings with lesion gross pathological and histopathological structure.

MRI of gynaecological solid masses

Differential diagnosis of gynaecological masses is sometimes difficult, as there are so many histological types. However, magnetic resonance characteristics of some gynaecological tumours have been reported past several years. On the basis of the recent literature, we have made a decision tree for differential diagnosis of solid gynaecological tumours, in which there are some important divergences. Bilateral disease and invasive growth are malignant signs in most cases. Specific findings for different tumour types include: fibrovascular septa in dysgerminomas; preserving ovarian follicles in round cell tumours; pseudolobular patterns in young patients in sclerosing stromal tumours; and extremely hypointense masses on T2WI in Brenner tumours. Distinguishing between sex-cord stromal tumours, Brenner tumours and metastatic tumours may be hard, however, especially in middle age, because they all tend to show well-demarcated, hypointense masses on T2WI. Disproportionately clear zonal anatomy of the uterus, enlarged uterus and thickened endometrium, which are indirect findings of oestrogen-producing tumours, are useful diagnostic findings in children and postmenopausals.

Brenner tumor of the ovary: CT and MR findings

PURPOSE

The purpose of this study was to determine the CT and MR characteristics of Brenner tumors, rare epithelial neoplasms of the ovary.

METHOD

CT and MR scans of eight pathologically proven Brenner tumors of the ovary (seven benign, one malignant, and one associated with mucinous cystadenoma) were retrospectively reviewed. The masses were analyzed for location, size, external configuration, internal architecture, enhancement pattern, presence of calcification, and metastatic spread.

RESULTS

The patients' median age was 63 years (range 39-79 years), and the mean size of the tumors was 11.4 cm (7.5-17 cm). All tumors were unilateral and had a well-defined margin. The mass was mostly solid in three, mostly cystic in one, and "mixed" solid and cystic in four cases. The tumors with cystic components (n = 5) were mostly multilocular in appearance (n = 4). All the solid components showed mild homogeneous enhancement on postcontrast CT and MRI. Extensive amorphous calcification within the solid component on CT was seen in five of six cases (83%). No characteristic findings discriminating malignancy from benign Brenner tumor could be found.

CONCLUSION

Extensive amorphous calcification in a solid mass or solid component in a multilocular cystic mass is a characteristic finding of Brenner tumor of the ovary on CT and MRI.

Uterine leiomyomas: histopathologic features, MR imaging findings, differential diagnosis, and treatment

Leiomyomas are the most common uterine neoplasm and are composed of smooth muscle with varying amounts of fibrous connective tissue. As leiomyomas enlarge, they may outgrow their blood supply, resulting in various types of degeneration: hyaline or myxoid degeneration, calcification, cystic degeneration, and red degeneration. Leiomyomas are classified as submucosal, intramural, or subserosal; the latter may become pedunculated and simulate ovarian neoplasms. Although most leiomyomas are asymptomatic, patients may present with abnormal uterine bleeding, pressure on adjacent organs, pain, infertility, or a palpable abdominalpelvic mass. Magnetic resonance (MR) imaging is the most accurate imaging technique for detection and localization of leiomyomas. On T2-weighted images, nondegenerated leiomyomas appear as well-circumscribed masses of decreased signal intensity; however, cellular leiomyomas can have relatively higher signal intensity on T2-weighted images and demonstrate enhancement on contrast material-enhanced images. Degenerated leiomyomas have variable appearances on T2-weighted images and contrast-enhanced images. The differential diagnosis of leiomyomas includes adenomyosis, solid adnexal mass, focal myometrial contraction, and uterine leiomyosarcoma. For patients with symptoms, medical or surgical treatment may be indicated. MR imaging also has a role in treatment of leiomyomas by assisting in surgical planning and monitoring the response to medical therapy.

Tissue characterization in the female pelvis by means of MR imaging

Pelvic imaging techniques such as computed tomography and ultrasonography provide a limited capability for tissue characterization. Fat, fluid, and calcification, for example, can be identified on the basis of parameters such as x-ray attenuation, echogenicity, and sound attenuation. Because of the many tissue parameters, such as T1, T2, magnetic susceptibility, and chemical shift, that contribute to signal intensity, magnetic resonance (MR) imaging may afford an ability to identify a wider array of specific tissues. The purpose of this article is to review the ability of MR imaging to help identify various types of soft tissue and to provide an approach to interpretation of MR images of the female pelvis through tissue characterization. Lipid, fluid, hemorrhage, smooth muscle, fibrosis, solid malignant tissue, and hydrated soft tissue (including edema, mucin, and myxomatous tissue) have typical MR imaging properties, and their presence in a mass can often be established on MR images. Consideration of the tissue composition of various pathologic processes in the pelvis can result in more systematic approaches to image interpretation and thus narrow the differential diagnosis.