Developing an MR imaging strategy for diagnosis of ovarian masses

Spontaneous T1-Hyperintensity Within an Ovarian Lesion: Spectrum of Diagnoses

Whenever elevated signal intensity is displayed at magnetic resonance imaging (MRI) within an ovarian lesion on unenhanced T1-weighted sequences, some specific diagnoses should be considered because only 3 main components may be responsible for this T1-hyperintensity at MRI: fat, blood products, and proteinaceous or mucinous material. The associated clinical data and concomitant use of T2-weighted sequences and fat-saturation techniques is mandatory to make this tissue characterization possible. The goal of this pictorial review is to provide a simple radiologic reasoning and the differential diagnoses to consider in the presence of spontaneous elevated signal intensity on T1-weighted sequences within a cystic or solid ovarian tumour.

Lesions of the ovary with T1-hypersignal

Pelvic magnetic resonance imaging (MRI) has been used successfully to diagnose ovarian masses that cannot be adequately evaluated using pelvic ultrasound. T1 hyperintensity is a common finding in an ovarian mass and has important diagnostic implications. The aims of this review are to list the substances that may produce high signal intensity on T1-weighted MRI, to explain the physical basis for causes of the high T1 signal intensity, and to describe common and uncommon T1 hyperintense ovarian lesions. The morphological findings, the imaging features of the additional sequences, and clinical variables can help in the differential diagnosis, and in some cases, enable a specific diagnosis, leading to appropriate management of the patient.

Pelvic MRI as the "gold standard" in the subsequent evaluation of ultrasound-indeterminate adnexal lesions: a systematic review

OBJECTIVE

Incidentally discovered adnexal masses are common, posing a challenging diagnostic problem because imaging features of benign and malignant overlap. Thus, once an adnexal lesion has been detected, the primary goal of further imaging is accurate tissue characterization resulting in surgery only for lesions that are indeterminate or frankly malignant. This study aims to conduct a systematic review, following the PRISMA guidelines, and critically appraise pelvic MR Imaging as the preferred advanced second imaging test, as regards detection of ovarian cancer and assessment of indeterminate adnexal masses, with respect to pre-operatively improving the assignment of these patients to the appropriate level of care.

METHODS

A comprehensive computerized systematic literature search of English language studies was performed (from 2002 to 2012) of PubMed, EMBASE, Scopus, Evidence Based Medicine Reviews (Cochrane Database and Cochrane Central Register of Controlled Trials), and Google Scholar. Relevant article reference lists were hand searched.

RESULTS

Computerized database search revealed 37 citations of relevance, 10 of which fulfilled the inclusion/exclusion criteria. From the aforementioned, 8 articles were acquired (2 authors were contacted but did not respond) as well as assessed with AHRQ, QUADAS, and STARD evaluation tools. Finally, 6 papers (5 prospective and 1 retrospective) were included in the systematic review.

CONCLUSIONS

MRI with intravenous (IV) contrast administration provides the highest post-test probability of ovarian cancer detection. However, the preponderant contribution of MRI in adnexal mass evaluation is its specificity because it provides confident diagnosis of many benign adnexal lesions.

MR imaging for acute nontraumatic abdominopelvic pain: rationale and practical considerations

Medical imaging is becoming an increasingly vital component of patient care in the emergency department. Computed tomography has been the diagnostic imaging method of choice for emergency department patients with acute abdominopelvic pain; however, the use of ionizing radiation and the potential need for exogenous contrast material adversely affect patient safety and work flow efficiency, respectively. Magnetic resonance (MR) imaging holds promise as an alternative for the evaluation of acute abdominopelvic pain. Critical causes of abdominopelvic pain may be detected with MR imaging without exogenous contrast material. MR imaging is sensitive for depicting tissue or fluid changes related to inflammation, a common process in causes of acute abdominopelvic pain. Fat suppression allows the detection of abnormal signal caused by inflamed tissue. MR imaging has proved sensitive in the detection of acute inflammatory diseases of the gallbladder and bile ducts, liver, pancreas, kidneys, collecting system, bowel, and pelvic soft tissues. Moreover, MR imaging without exogenous contrast material may be safely used in pregnant patients. Evolving roles for emergency department MR imaging include the assessment of vascular disease (including thromboembolic disease) and right upper quadrant pain. Emergency department MR imaging currently has limited availability, and its continued use will require further education regarding operation and image interpretation as well as further validation of cost-effectiveness. Nevertheless, current understanding of the diagnostic utility of this imaging method warrants continued study and the increased use of MR imaging in the evaluation of emergency department patients with acute abdominopelvic pain.

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.

Ovarian fibromas: MR imaging findings with emphasis on intratumoral cyst formation

PURPOSE

The purpose of this study was to assess MR imaging findings of ovarian fibromas with emphasis on intratumoral cyst formation.

MATERIALS AND METHODS

MR images with a 1.5-T unit obtained in 17 consecutive patients (age range, 18-87 years; mean age, 58 years) with 17 histologically proven ovarian fibromas were retrospectively reviewed for the size, configuration, signal intensity of solid components, and presence of cystic degeneration and edema within tumor. Size, number, and location of intratumoral cysts were also assessed.

RESULTS

The maximum diameter of tumors ranged from 3.3 to 19.1cm (mean, 10.9 cm). Seven (41%) tumors were multinodular. On T2-weighted images, solid components of tumors were heterogeneously mixed hypo- and hyperintensity in 16 (94%) tumors. Nine (53%) tumors demonstrated cysts and 16 (94%) demonstrated edema within tumor. The maximum diameter of the largest cysts ranged from 1.0 to 13.2 cm (mean, 6.4 cm), and the number of cysts per tumor ranged from 1 to 60 (mean, 15.6). Of the nine tumors with cystic formation, the predominant location of the cysts was peripheral in five (56%), exophytic in two (22%), central (11%) in one, and diffuse in one (11%).

CONCLUSION

Peripheral or exophytic cyst formation may be characteristic MR imaging features with ovarian fibromas.

Characterization of Ovarian Tumors and Staging Ovarian Cancer With 3-Dimensional Power Doppler Angiography: Correlation With Pathologic Findings

Objective

The aims of this study were to evaluate ovarian tumors with 3-dimensional power Doppler angiography (3-DPDA), to determine its correlation with histology findings, and to explore its role in staging patients with ovarian cancer.

Methods

Three hundred eighteen women with an unknown unilateral pelvic mass were referred for preoperative evaluation by 3-DPDA angiography. Patients’ ages ranged from 18 to 72 years (47.4 ± 13.8 years). Sonographic criteria used for the characterization of ovarian tumors were based on a system that included morphological characteristics, histological evaluation, and Power Doppler imaging.

Results

Two hundred twenty-five tumors were histopathologically diagnosed as benign and 93 as malignant. Sensitivity and specificity of the 3-DPDA of ovarian masses reached 93.5% and 92.9%, respectively, whereas positive predictive value was 84.5% and negative predictive value was 97.2%.

Conclusions

Three-dimensional power Doppler sonography is an effective imaging technique for discriminating ovarian neoplasms and classifying them according to histopathology.

Benign and Suspicious Ovarian Masses-MR Imaging Criteria for Characterization: Pictorial Review

Ovarian masses present a special diagnostic challenge when imaging findings cannot be categorized into benign or malignant pathology. Ultrasonography (US), Computed Tomography (CT), and Magnetic Resonance Imaging (MRI) are currently used to evaluate ovarian tumors. US is the first-line imaging investigation for suspected adnexal masses. Color Doppler US helps the diagnosis identifying vascularized components within the mass. CT is commonly performed in preoperative evaluation of a suspected ovarian malignancy, but it exposes patients to radiation. When US findings are nondiagnostic or equivocal, MRI can be a valuable problem solving tool, useful to give also surgical planning information. MRI is well known to provide accurate information about hemorrhage, fat, and collagen. It is able to identify different types of tissue contained in pelvic masses, distinguishing benign from malignant ovarian tumors. The knowledge of clinical syndromes and MRI features of these conditions is crucial in establishing an accurate diagnosis and determining appropriate treatment. The purpose of this paper is to illustrate MRI findings in neoplastic and non-neoplastic ovarian masses, which were assessed into three groups: cystic, solid, and solid/cystic lesions. MRI criteria for the correct diagnosis and characteristics for differentiating benign from malignant conditions are shown in this paper.

Normal and variant pelvic anatomy on MRI

The superior tissue contrast and flexible imaging planes afforded by magnetic resonance imaging (MRI) versus competing technologies permit optimal depiction of the pelvic viscera. Targeted protocols developed for specific pelvic visceral organs highlight important anatomic features that may not be imaged by other modalities. Therefore, a solid understanding of normal and variant pelvic anatomy is crucial for appropriate interpretation of pelvic MRI studies. This article discusses the protocol strategies and relevant anatomy with commonly encountered anatomical variants in a segmented/organ-specific manner, using gender as a broad split given the substantial variance in relevant organs.

Spectrum of mucin-producing neoplastic conditions of the abdomen and pelvis: cross-sectional imaging evaluation

Various mucin-producing neoplasms originate in different abdominal and pelvic organs. Mucinous neoplasms differ from non-mucinous neoplasms because of the differences in clinical outcome and imaging appearance. Mucinous carcinoma, in which at least 50% of the tumor is composed of large pools of extracellular mucin and columns of malignant cells, is associated with a worse prognosis. Signet ring cell carcinoma is characterized by large intracytoplasmic mucin vacuoles that expand in the malignant cells with the nucleus displaced to the periphery. Its prognosis is also generally poor. In contrast, intraductal papillary mucinous neoplasm of the bile duct and pancreas, which is characterized by proliferation of ductal epithelium and variable mucin production, has a better prognosis than other malignancies in the pancreaticobiliary tree. Imaging modalities play a critical role in differentiating mucinous from non-mucinous neoplasms. Due to high water content, mucin has a similar appearance to water on ultrasound (US), computed tomography (CT), and magnetic resonance imaging, except when thick and proteinaceous, and then it tends to be hypoechoic with fine internal echoes or have complex echogenicity on US, hyperdense on CT, and hyperintense on T1- and hypointense on T2-weighted images, compared to water. Therefore, knowledge of characteristic mucin imaging features is helpful to diagnose various mucin-producing neoplastic conditions and to facilitate appropriate treatment.

Bilateral ovarian fibrothecoma. An uncommon cause of a large pelvic mass

Ovarian fibrothecomas are uncommon tumors of gonadal stromal cell origin. They account for 3-4% of all ovarian tumors and in 90% of the cases are unilateral. Here, we describe a rare case of a bilateral ovarian fibrothecoma in a postmenopausal woman who presented with a large pelvic mass and metrorrhagia. Diagnostic evaluation and surgical management are discussed along with a brief review of the literature. Although rare, ovarian fibrothecoma should be considered in patients presenting with a large pelvic mass and postmenopausal bleeding. Radical surgery is the preferred management strategy for postmenopausal women with bilateral ovarian fibrothecomas and is associated with a good prognosis.

Perfusion fraction of diffusion-weighted MRI for predicting the presence of blood supply in ovarian masses

PURPOSE

To evaluate whether perfusion fraction (PF) calculated with diffusion-weighted magnetic resonance imaging (MRI) predicts the presence of blood supply in ovarian masses.

MATERIALS AND METHODS

PFs of 92 ovarian lesions in 53 patients administered gadolinium were retrospectively calculated with diffusion-weighted images at b-values of 0, 500, and 1000 sec/mm(2). PFs were compared between ovarian lesions, except for fat, with (n = 21) or without contrast enhancement (n = 57), using Student's t-test and receiver operating characteristics (ROC) curve analysis. Lesion enhancement rates of contrast-enhanced images at 30 and 180 seconds after gadolinium injection (ER(30sec) and ER(180sec)) and PFs were compared using Pearson's correlation coefficient.

RESULTS

PFs of the lesions with contrast enhancement were significantly higher than those without contrast enhancement (0.22 ± 0.09 and 0.02 ± 0.08, respectively, P < 0.0001). The ROC curve identified the best cutoff point for PF at 0.135 (95.2% sensitivity and 94.7% specificity) as a predictor of the contrast enhancement effect. The area under the ROC curve was 0.984. PF correlated moderately with ER(30sec) (0.62, y = 0.13x + 0.04, P < 0.0001) and ER(180sec) (0.74, y = 0.13x + 0.03, P < 0.0001).

CONCLUSION

PF calculated with diffusion-weighted images can potentially predict blood supply in ovarian masses.

MR-PET fusion imaging in evaluating adnexal lesions: a preliminary study

PURPOSE

The objective of this preliminary study was to examine the effects of combined magnetic resonance/positron emission tomography (MR-PET) evaluation in the morphofunctional characterisation of ovarian lesions.

MATERIALS AND METHODS

From June 2008 to September 2010, we evaluated 24 patients (mean age 44±10 years; range 24-74) with ovarian lesions incidentally detected on ultrasonography (US) and/or multislice computed tomography (CT). All patients underwent MR imaging of the pelvis and total-body CT-PET. PET and MR images were subsequently fused at postprocessing using specific anatomical criteria. Results were compared with the histological examination.

RESULTS

Of the 24 examined lesions, 19 were malignant and five were benign on histological examination. MR, CT-PET and MR-PET sensitivity was 84%, 74% and 94%, respectively and specificity 60%, 80% and 100%, respectively. Positive (PPV) and negative predictive (NPV) values were 93% and 44% for CT-PET, 89% and 50% for MR and 100% and 83% for MR-PET, respectively.

CONCLUSIONS

Pelvic MR-PET fusion imaging provides advantages in terms of sensitivity and especially specificity compared with MR imaging or CT-PET alone. The added value of this fusion imaging modality lies in combining the benefits of the morphological evaluation provided by MR imaging and the metabolic assessment provided by PET.

Imaging of pediatric ovarian neoplasms

We review the clinical and imaging characteristics of the most common ovarian neoplasms in children and adolescents. Because of the widespread use of diagnostic imaging, incidental ovarian neoplasms might be encountered during the evaluation of abdominal pain, trauma or other indications and might pose a diagnostic dilemma. Conducting adequate imaging studies under these conditions is important, as management strategies differ according to the size and appearance of the lesion as well as the age of the patient. US dominates in gynecological imaging because of its excellent visualization, absence of ionizing radiation and sedation risks and comparatively low cost. For further examination of indeterminate lesions found using US, MRI is being used more progressively in this field, particularly for the evaluation of complex pelvic masses with the aim of distinguishing benign and malignant conditions and conditions requiring surgical intervention. CT is reserved primarily for tumor staging and follow-up and for emergency situations.

Role of multidetector computed tomography (MDCT) in patients with ovarian masses

Objective:

To evaluate the diagnostic accuracy of multidetector 64-slice computed tomography (MDCT) in the diagnosis and differentiation of benign and malignant ovarian masses using histopathology and surgical findings as the gold standard.

Material and methods:

This study was conducted in Aga Khan University Hospital, Karachi, Pakistan. Data was reviewed retrospectively from 1 November 2008 to 12 December 2009. One hundred patients found to have ovarian masses on CT scan were included in the study. CT scan was performed in all these patients after administration of oral and IV contrast. Ovarian masses were classified as benign and malignant on scan findings. Imaging findings were compared with histopathologic results and surgical findings. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of MDCT were calculated.

Results:

MDCT was found to have 97% sensitivity, 91% specificity, and an accuracy of 96% in the differentiation of benign and malignant ovarian masses, while PPV and NPV were 97% and 91%, respectively.

Conclusion:

MDCT imaging offers a safe, accurate and noninvasive modality to differentiate between benign and malignant ovarian masses.

MRI of the female pelvis: a possible pitfall in the differentiation of haemorrhagic vs. fatty lesions using fat saturated sequences with inversion recovery

The use of fat-saturated techniques should be an integral part of the work-up of any T1-hyperintense structure in the female pelvis for tissue characterization and for differentiation of a fat-containing ovarian mature teratoma from a haemorrhagic lesion. Two cases with haematocolpos and haematometra are presented, respectively. The haemorrhagic content showed high signal both on T1- and T2-weighted images, whereas an unexpected signal decrease in the fat-saturated T2-weighted inversion-recovery sequence was encountered. This unspecific suppression of signal in tissues with similar T1 relaxation times as fat can lead to a diagnostic pitfall both in T1- and T2-weighted STIR pulse sequences. Furthermore, a loss of signal on T2-weighting may also be due to the phenomenon of "T2-shading" in T1-bright ovarian endometrioma. Therefore, the fat-specific spectral fat-saturation of T1-weighted images is strongly recommended for tissue characterization in gynaecological disease.

Diffusion-weighted imaging of solid or predominantly solid gynaecological adnexial masses: is it useful in the differential diagnosis?

OBJECTIVES

This study investigated whether diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) values provide specific information that allows the diagnosis of solid or predominantly solid gynaecological adnexial lesions, especially whether they can discriminate benign and malignant lesions.

METHODS

DWI was performed in 37 patients with histologically proven solid or predominantly solid adnexial lesions (22 malignant and 15 benign neoplasms). The lesions in our data set were divided into two groups, all adnexial lesions or lesions of ovarian origin, for evaluation. The areas of the highest signal intensity on DWI (b = 800 s mm(-2)) and the lowest ADC values within the lesions were evaluated.

RESULTS

On DWI, high signal intensity was observed more often in malignant than in benign lesions (p<0.0001). There was no significant difference between the ADC values of the malignant and benign lesions in either the adnexial (0.88±0.16 vs 0.84±0.42; p = 0.96) or the ovarian (0.85±0.14 vs 1.05±0.2; p = 0.133) lesions. When signal intensities on DWI were compared, however, malignant lesions had higher values than the benign lesions in both the adnexial (0.69±0.21 vs 0.29±0.13; p<0.0001) and the ovarian lesions (0.75±0.14 vs 0.37±0.24; p = 0.003).

CONCLUSION

On DWI, high signal intensity was observed more frequently with the malignant lesions.

Imaging of benign adnexal masses: characteristic presentations on ultrasound, computed tomography, and magnetic resonance imaging

Adnexal masses are common in the general population. Although ovarian cancer is a significant cause of mortality, large screening studies demonstrate that the majority of adnexal masses are benign. These benign masses include physiologic cysts, paraovarian masses, and benign ovarian lesions. It is important that gynecologists and radiologists appreciate the appearance of these lesions on multiple imaging modalities, including ultrasound, computed tomography, and magnetic resonance imaging to avoid unnecessary intervention.

High-field magnetic resonance imaging of the pelvis: uterus, ovary, and prostate gland

Today, magnetic resonance imaging (MRI) is a standard imaging modality for various pathologic disorders in the human pelvis. It has given proof of its usefulness in the diagnosis of several benign and malignant disorders, and it is routinely used for the local staging of different tumors even when confined to specific parts of a pelvic organ. Signal-to-noise ratio and motion artifacts of the examined organ and adjacent bowel structures are major factors for image quality. Setting at 3 T with surface coils avoids technical limitations and discomfort of additional endovaginal or endorectal coils. Definition of high field seems fuzzy because of the availability of MRI machines with 3, 7 T, or higher; therefore, the general aspects of MRI of pelvic structures with emphasis on uterus, ovary, and prostate gland and attention to promising newer techniques such as 3 T, dynamic contrast imaging, and diffusion-weighted imaging are reviewed in this article.

MRI, CT, and PET/CT for ovarian cancer detection and adnexal lesion characterization

OBJECTIVE

The purpose of this article is to describe the role of MR, CT, and PET/CT in the detection of ovarian cancer and the evaluation of adnexal lesions.

CONCLUSION

The goal of imaging in ovarian cancer detection is to expeditiously distinguish benign adnexal lesions from those requiring further pathologic evaluation for malignancy. For lesions indeterminate on ultrasound, MRI increases the specificity of imaging evaluation, thus decreasing benign resections. CT is useful in diagnosis and treatment planning of advanced cancer. Although (18)F-FDG-avid ovarian lesions in postmenopausal women are considered suspicious for malignancy, PET/CT is not recommended for primary cancer detection because of high false-positive rates.

[MR Imaging of primary ovarian tumors with pathologic correlation]

Ovarian tumors are classified based on the cell of origin into epithelial tumors, germ cell tumors and sex cord-stromal tumors. This pictorial essay illustrates the MR imaging features of the main ovarian tumors with pathologic correlation. These key features are helpful to suggest a specific diagnosis or narrow the differential diagnosis, in order to optimize the surgical approach.

Diagnostic accuracy of diffusion-weighted imaging in differentiating benign from malignant ovarian lesions

PURPOSE

To clarify the diagnostic accuracy of diffusion-weighted imaging (DWI) in differentiating benign from malignant ovarian lesions.

MATERIALS AND METHODS

We retrospectively analyzed magnetic resonance images of 123 ovarian lesions in 119 patients. We defined lesions with abnormal signal intensity as malignancy and assessed the location of abnormal intensity within the lesions on DWI. We also assessed the mean and lowest apparent diffusion coefficient (ADC) values of the solid portion for each ovarian lesion.

RESULTS

The majority of malignant ovarian tumors and mature cystic teratomas, and almost half of the endometriomas, showed abnormal signal intensity on DWI, whereas most fibromas and other benign lesions did not. The main locations of abnormal signal intensity were solid portions in malignant ovarian tumors, cystic components suggestive of keratinoid substances and Rokitansky protuberance in mature cystic teratomas, and intracystic clots in endometriomas. On DW imaging, receiver-operating characteristic analysis yielded mean Az values of 0.703. There was no significant difference in mean and lowest ADC values between malignant and benign lesions.

CONCLUSION

DWI of ovarian lesions and ADC values of the solid component are not useful for differentiating benign from malignant ovarian lesions. This knowledge is essential in avoiding misinterpretation in the diagnosis of ovarian lesions.

Magnetic resonance imaging of cystic adnexal lesions during pregnancy

Management of cystic adnexal lesions diagnosed during pregnancy is a challenging issue for obstetricians. The range of treatment options changes from immediate surgery to close follow-up. This pictorial essay illustrates the magnetic resonance imaging findings of various cystic adnexal lesions in pregnant patients. Magnetic resonance imaging may help in better characterization of some of the cystic adnexal lesions diagnosed during pregnancy without exposing the fetus to ionizing radiation.

Acute abdomen due to twisted ovarian immature teratoma in a 7-year-old girl: magnetic resonance findings with histopathologic correlation

Immature teratomas represent only the 1% of ovarian teratomas, and they are the third most common primitive germ cell tumor; generally, they are congenital lesions and affect mainly the first 2 decades. We present the case of a 7-year-old child who came at our attention because of an acute low abdominal pain due to the torsion of an ovarian immature grade 1 teratoma on its pedicle. After ultrasound in the emergency department, preoperative evaluation was done by performing a magnetic resonance study, whose findings helped in suggesting the curative approach. The magnetic resonance imaging characteristics of the neoplasm are reviewed and correlated with histopathologic findings. As it was highlighted in our case, magnetic resonance imaging may be part of the diagnostic approach of this rare disease entity also in a small child in emergency.

Diagnostic accuracy of 18F-FDG PET/CT in characterizing ovarian lesions and staging ovarian cancer: correlation with transvaginal ultrasonography, computed tomography, and histology

AIMS

To (a) assess the accuracy of 18F-FDG PET/CT in distinguishing malignant from benign pelvic lesions, compared to transvaginal ultrasonography (TVUS) and (b) to establish the role of whole-body 18F-FDG PET/CT, compared to contrast enhanced computed tomography (CT), in staging patients with ovarian cancer.

PATIENTS

Fifty consecutive patients with a pelvic lesion, already scheduled for surgery on the basis of physical examination, TVUS, and serum Ca125 levels, were enrolled in the study. Patients' age ranged between 23 and 89 years (mean 64). All patients underwent TVUS including a colour Doppler study followed by a thorax and abdominal CT scan, and whole-body 18F-FDG PET/CT within 2 weeks prior to surgery. Histological findings obtained at surgery were taken as the 'gold standard' to compare 18F-FDG PET/CT and TVUS, and 18F-FDG PET/CT vs. CT. When tissue analysis showed ovarian cancer, the accuracy of 18F-FDG PET/CT and CT were compared for the purpose of obtaining a precise staging.

RESULTS

At surgery, the ovarian lesions were malignant in 32/50 patients (64%) and benign in the remaining 18/50 patients (36%). The sensitivity, specificity, NPV, PPV and accuracy of 18F-FDG PET/CT were 87%, 100%, 81%, 100% and 92%, respectively, compared with 90%, 61%, 78%, 80% and 80%, respectively, for TVUS. In staging ovarian cancer, 18F-FDG PET/CT results were concordant with final pathological staging in 22/32 (69%) patients while CT results were concordant in 17/32 (53%) patients. CT incorrectly down-staged four out of six stage IV patients by missing distant metastasis in the liver, pleura, mediastinum, and in left supraclavicular lymph nodes, which were correctly detected by 18F-FDG PET/CT.

CONCLUSION

PET/CT with 18F-FDG provides additional value to TVUS for the differential diagnosis of benign from malignant pelvic lesions, and to CT for the staging of ovarian cancer patients.

Detection of peritoneal dissemination in gynecological malignancy: evaluation by diffusion-weighted MR imaging

The aim of this study is to evaluate the usefulness of diffusion-weighted (DW) magnetic resonance (MR) imaging in detecting peritoneal dissemination in cases of gynecological malignancy. We retrospectively analyzed MR images obtained from 26 consecutive patients with gynecological malignancy. Peritoneal dissemination was histologically diagnosed in 15 of the 26 patients after surgery. We obtained DW images and half-Fourier single-shot turbo-spin-echo images in the abdomen and pelvis, and then generated fusion images. Coronal maximum-intensity-projection images were reconstructed from the axial source images. Reader interpretations were compared with the laparotomy findings in the surgical records. Receiver-operating characteristic (ROC) curves were used to represent the presence of peritoneal dissemination. In addition, the sensitivity and specificity were calculated. DW imaging depicted the tumors in 14 of 15 patients with peritoneal dissemination as abnormal signal intensity. ROC analysis yielded Az values of 0.974 and 0.932 for the two reviewers. The mean sensitivity and specificity were 90 and 95.5%. DW imaging plays an important role in the diagnosis and therapeutic management of patients with gynecological malignancy.

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.

Magnetic resonance imaging of abdominal pain during pregnancy

The objective of this review is to demonstrate magnetic resonance imaging as an important adjunct to ultrasound and computed tomography in the evaluation of the pregnant patient with abdominal pain. With the advent of ultrafast T2-weighted pulse sequences, fetal and bowel motion cause minimal artifact on the images. An accurate diagnosis can often be made in a few minutes based on these high-contrast images performed in 2 or 3 planes. T1-weighted gradient echo images with and without fat saturation are useful for identifying blood and fat, especially in the case of adnexal masses. Gadolinium-diethylenetriamine pentaacetic acid is rarely used to diagnose inflammatory or obstructive disease and is reserved for those patients with suspected malignancies.

MR Imaging Evaluation of Acute Abdominal Pain During Pregnancy

MR imaging enables diagnosis of a variety of maternal diseases presenting as acute abdominal pain in pregnant patients. MR imaging is a valuable complement to ultrasound in the determination of the exact etiology of acute abdominal pain, and it is important for the radiologist to recognize the MR imaging appearance of common causes of acute abdominal pain during pregnancy. This article reviews the MR imaging technique and findings of various abnormalities causing acute abdominal pain in pregnant patients.