Elizabeth A. Sadowski

Optimizing technical parameters to the specifications of the Ovarian-Adnexal Reporting and Data System (O-RADS) MRI protocol is necessary to achieve the positive predictive values listed in the O-RADS MRI risk table and to accurately assess the risk of cancer in lesions referred for MRI.

Solid components and multilocularity were frequently found among benign lesions scored as Ovarian-Adnexal Reporting and Data System (O-RADS) 4 or 5, with cystadenomas and cystadenofibromas being the most common benign lesions.

US is a valuable tool for assessing ovarian and adnexal lesions but is an operator-dependent modality, and it is crucial to optimize US technique to enhance O-RADS accuracy for reliable characterization and malignancy risk assessment.

Radiologists use CT, along with diffusion-weighted MRI and sometimes PET, to assess disease extent, including peritoneal carcinomatosis, in advanced ovarian cancer, preferably applying systematic image interpretation and disease-specific structured reporting to enhance communication and support decision-making.

Even among nine expert readers, CT diagnosis was not reproducible and was frequently incorrect for most adnexal lesion types, excluding dermoids, malignant ovarian lesions with metastases, and simple cysts.

The interpretation of gynecologic pelvic MRI benefits from tailored MRI protocols, radiologists' knowledge of normal female pelvic anatomy, and a step-by-step approach focusing on lesion origin, lesion tissue composition, and solid tissue morphology, with findings presented in a structured report.

Among ovarian and adnexal lesions surgically removed before 2015, a large proportion were retrospectively assessed as Ovarian-Adnexal Imaging Reporting and Data System US 2, which may have allowed for more conservative management in these patients.

Ovarian-Adnexal Reporting and Data System US and MRI provide evidence-based lexicons and risk assessment systems that can accurately diagnose most adnexal lesions as benign and effectively risk stratify those that are suspicious for malignancy.

Fluorine 18-fluorodeoxyglucose (FDG) PET and MRI independently play a valuable role in the management of patients with gynecologic malignancies, particularly endometrial and cervical cancer. The PET/MRI hybrid imaging technique combines the metabolic information obtained from PET with the excellent soft-tissue resolution and anatomic details provided by MRI in a single examination. MRI is the modality of choice for assessment of local tumor extent in the pelvis, whereas PET is used to assess for local-regional spread and distant metastases. The authors discuss the added value of FDG PET/MRI in imaging gynecologic malignancies of the pelvis, with a focus on the role of FDG PET/MRI in diagnosis, staging, assessing treatment response, and characterizing complications. PET/MRI allows better localization and demarcation of the extent of disease, characterization of lesions and involvement of adjacent organs and lymph nodes, and improved differentiation of benign from malignant tissues, as well as detection of the presence of distant metastasis. It also has the advantages of decreased radiation dose and a higher signal-to-noise ratio of a prolonged PET examination of the pelvis contemporaneous with MRI. The authors provide a brief technical overview of PET/MRI, highlight how simultaneously performed PET/MRI can improve stand-alone MRI and PET/CT in gynecologic malignancies, provide an image-rich review to illustrate practical and clinically relevant applications of this imaging technique, and review common pitfalls encountered in clinical practice. ^©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

The Ovarian-Adnexal Reporting and Data System (O-RADS) MRI risk stratification system provides a standardized lexicon and evidence-based risk score for evaluation of adnexal lesions. The goals of the lexicon and risk score are to improve report quality and communication between radiologists and clinicians, reduce variability in the reporting language, and optimize management of adnexal lesions. The O-RADS MRI risk score is based on the presence or absence of specific imaging features, including the lipid content, enhancing solid tissue, number of loculi, and fluid type. The probability of malignancy ranges from less than 0.5% when there are benign features to approximately 90% when there is solid tissue with a high-risk time-intensity curve. This information can aid in optimizing management of patients with adnexal lesions. The authors present an algorithmic approach to the O-RADS MRI risk stratification system and highlight key teaching points and common pitfalls. ^© RSNA, 2023 Quiz questions for this article are available in the supplemental material.