MAGNETIC RESONANCE IMAGING OF THE OVARY

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.

Distinguishing benign and malignant pelvic masses: The value of different diagnostic methods in everyday clinical practice

OBJECTIVE

To optimize referral to specialized gynaecologists for surgical treatment of ovarian cancer by improving preoperative discrimination between benign and malignant pelvic tumours.

STUDY DESIGN

In a prospective multicentre study 143 patients with a pelvic mass were included. At several occasions during the diagnostic work-up the gynaecologist estimated the chance of malignancy (educated guess/expert opinion). MRI in the local setting was suggested for uncertain cases. All MRI images were reviewed by an expert radiologist. The datasheet designed for the study further allowed for determining the risk of malignancy index (RMI).

RESULTS

The diagnostic accuracy of the gynaecologist's final estimation of the chance of malignancy and the calculated RMI were comparable (area under the ROC curve of 0.87 and 0.86). MRI did not improve the accuracy of the diagnostic work-up for the study population as a whole. Subgroup analysis did however show improved diagnostic accuracy in cases with an estimated chance of malignancy between 20 and 80% when the MRI was read by an expert radiologist.

CONCLUSION

Patient selection for surgery of a pelvic mass should be based on the chance of malignancy as assigned by the referring gynaecologists. In case of uncertainty MRI improves diagnostic accuracy, when judged by an expert.

Une exentération pelvienne postérieure avec anastomose est-elle faisable et justifiée dans le traitement des cancers de l'ovaire à un stade évolué ?

PURPOSE

The aim of this study is to show that the removal of the rectum is not an obstacle to implement an optimal surgery in advanced epithelial cancer of the ovary.

MATERIAL AND METHODS

Retrospective study on a population of 44 women with advanced epithelial cancer of the ovary. The surgery was realized between January 95 and July 03, and all surgeries required a posterior exenteration. This treatment was completed by chemotherapy for 36 of them.

RESULTS

The median survival of this population is 36.6 months. 6/44 patients (13.6%) had post-operative complications. The completion of chemotherapy started after an average of 5.2 weeks after surgery. All the assessable patients (43/44) have an anal satisfactory continence.

CONCLUSION

The posterior exenteration, when it's necessary, for advanced epithelial cancer of the ovary must not be an obstacle to obtain an optimal surgery. Anal continence is respected and there are no more complications. This surgical act is safe for the management of this pathology without delaying the others therapeutics and allowing a satisfactory quality of life.

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.

Papillary projections in ovarian neoplasms: appearance on MRI

Papillary projections are distinctive pathologic features of epithelial ovarian neoplasms. We sought to determine whether these structures have recognizable features on MRI. A search of a database of 125 patients on whom MRI was performed with pelvic phased-array coil and abdominal surgical exploration was performed for suspected gynecologic disease identified 15 patients who had either MRI reports or pathology reports mentioning papillary projections in an adnexal mass. The MR images were reviewed to characterize the size, structure, and signal intensity of papillary projections. Pathologic correlation was performed on these and on four surgical specimens imaged with high resolution technique. Pathologic correlation showed that larger papillary projections had a distinctive structure of a fibrous stalk supporting clumps of edematous papillae with signal intensity similar to that of fluid on T2-weighted images. Smaller papillae showed nondescript intracystic projections of intermediate signal intensity on T2-weighted images. All papillary projections in vivo enhanced after injection of gadopentetate dimeglumine. Papillary projections have an appearance on MRI that reflects their histologic structure.