Added Value of FDG PET/MRI in Gynecologic Oncology: A Pictorial Review

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.

Vulvar Cancer: 2021 Revised FIGO Staging System and the Role of Imaging

Vulvar cancer is a rare gynecological malignancy. It constitutes 5-8% of all gynecologic neoplasms, and squamous cell carcinoma is the most common variant. This article aims to review the etiopathogenesis revised 2021 International Federation of Gynecology and Obstetrics (FIGO) classification and emphasize imaging in the staging of vulvar cancer. The staging has been regulated by FIGO since 1969 and is subjected to multiple revisions. Previous 2009 FIGO classification is limited by the prognostic capability, which prompted the 2021 revisions and issue of a new FIGO classification. Although vulvar cancer can be visualized clinically, imaging plays a crucial role in the staging of the tumor, assessing the tumor extent, and planning the management. In addition, sentinel lymph node biopsy facilitates the histopathological staging of the draining lymph node, thus enabling early detection of tumor metastases and better survival rates.

Gynecologic tumor board: a radiologist's guide to vulvar and vaginal malignancies

Primary vulvar and vaginal cancers are rare female genital tract malignancies which are staged using the 2009 International Federation of Gynecology and Obstetrics (FIGO) staging. These cancers account for approximately 2,700 deaths annually in the USA. The most common histologic subtype of both vulvar and vaginal cancers is squamous cell carcinoma, with an increasing role of the human papillomavirus (HPV) in a significant number of these tumors. Lymph node involvement is the hallmark of FIGO stage 3 vulvar cancer while pelvic sidewall involvement is the hallmark of FIGO stage 3 vaginal cancer. Imaging techniques include computed tomography (CT), positron emission tomography (PET)-CT, magnetic resonance imaging (MRI), and PET-MRI. MRI is the imaging modality of choice for preoperative clinical staging of nodal and metastatic involvement while PET-CT is helpful with assessing response to neoadjuvant treatment and for guiding patient management. Determining the pretreatment extent of disease has become more important due to modern tailored operative approaches and use of neoadjuvant chemoradiation therapy to reduce surgical morbidity. Moreover, imaging is used to determine the full extent of disease for radiation planning and for evaluating treatment response. Understanding the relevant anatomy of the vulva and vaginal regions and the associated lymphatic pathways is helpful to recognize the potential routes of spread and to correctly identify the appropriate FIGO stage. The purpose of this article is to review the clinical features, pathology, and current treatment strategies for vulvar and vaginal malignancies and to identify multimodality diagnostic imaging features of these gynecologic cancers, in conjunction with its respective 2009 FIGO staging system guidelines.

MRI Staging in Locally Advanced Vulvar Cancer: From Anatomy to Clinico-Radiological Findings. A Multidisciplinary VulCan Team Point of View

MR imaging provides excellent spatial and contrast resolution to stage locally advanced vulvar cancer (LAVC) for tumor and nodal evaluation in order to facilitate the planning of treatment. Although there are no standard indications for how to estimate the clinical stage of International Federation of Gynecology and Obstetrics at diagnosis, MR imaging can depict the tumor and its extension to the vulvar region and adjacent organs, such as the vagina, urethra, and anus. Optimizing the MR imaging protocol and technique is fundamental for correct staging. The aim of this overview was to focus on the role of MR imaging in LAVC staging. We define vulvar anatomy and corresponding MR imaging findings, MR imaging protocol, and technique. Moreover, we describe the MR imaging findings of LAVC with example cases stage by stage. Key imaging findings based on signal intensity, diffusion restriction, and enhancement are portrayed to correctly identify and stage vulvar cancer. A structured report for LAVC staging is reported in order to give all necessary information to the clinicians and to facilitate MR imaging comprehension.

Vulvar cancer staging: guidelines of the European Society of Urogenital Radiology (ESUR)

Objective

The aim of the Female Pelvic Imaging Working Group of the European Society of Urogenital Radiology (ESUR) was to develop imaging staging guidelines for vulvar cancer and to propose standardised MRI protocols and reporting.

Methods

The guidelines recommended from the ESUR in this article resulted from a questionnaire analysis regarding imaging staging of vulvar cancer that was answered by all members of the Female Pelvic Imaging Working Group. Only the answers with an agreement equal to or more than 80% were considered. Additionally, the literature was reviewed to complement and further support our conclusions.

Results

The critical review of the literature and consensus obtained among experts allows for recommendations regarding imaging staging guidelines, patient preparation, MRI protocol, and a structured MRI report.

Conclusions

Standardising image acquisition techniques and MRI interpretation reduces ambiguity and ultimately improves the contribution of radiology to the staging and management of patients with vulvar cancer. Moreover, structured reporting assists with the communication of clinically relevant information to the referring physician.

Current Status of Anatomical Magnetic Resonance Imaging in Brachytherapy and External Beam Radiotherapy Planning and Delivery

Radiotherapy planning and delivery have dramatically improved in recent times. Imaging is key to a successful three-dimensional and increasingly four-dimensional based pathway with computed tomography embedded as the backbone modality. Computed tomography has significant limitations for many tumour sites where soft-tissue discrimination is suboptimal, and where magnetic resonance imaging (MRI) has largely superseded in the diagnostic arena. MRI is increasingly used together with computed tomography in the radiotherapy planning pathway and is now established as a prerequisite for several tumours. With the advent of combined MRI and linear accelerator (MR-linac) systems, a transition to MRI-based radiotherapy planning is becoming reality, with increasing experience and research involving these new platforms. In this overview, we aim to highlight how magnetic resonance-guided imaging has improved radiotherapy, using gynaecological malignancies to illustrate, in both external beam radiotherapy and image-guided brachytherapy, and will assess the early evidence for magnetic resonance-guided radiotherapy using combined MR-linac systems.

Ultrasound morphometric and cytologic preoperative assessment of inguinal lymph-node status in women with vulvar cancer: MorphoNode study

OBJECTIVE

To assess the accuracy of preoperative ultrasound examination for predicting lymph-node (LN) status in patients with vulvar cancer.

METHODS

This was a single-institution retrospective observational study of all women with a histological diagnosis of vulvar cancer triaged to inguinal surgery within 30 days following ultrasound evaluation between December 2010 and January 2016. For each groin examined, 15 morphological and dimensional sonographic parameters associated with suspicion for LN involvement were examined. A morphometric ultrasound pattern (MUP) was expressed for each groin, classifying the inguinal LN status into five groups (normal; reactive-but-negative; minimally suspicious/probably negative; moderately suspicious; and highly suspicious/positive) according to subjective judgment, followed by stratification as positive or negative for metastasis according to morphometric binomial assessment (MBA). In cases of positive MBA, fine-needle aspiration cytology was performed. Combining the information obtained from MUP and cytologic results, a binomial final overall assessment (FOA) was assigned for each groin. The final histology was considered as the reference standard. Comparison was performed between patients with negative and those with positive LNs on histology, and receiver-operating-characteristics curves were generated for statistically significant variables on univariate analysis, to evaluate their diagnostic ability to predict negative LN status.

RESULTS

Of 144 patients included in the analysis, 87 had negative inguinal LNs and 57 had positive LNs on histology. A total of 256 groins were analyzed, of which 171 were negative and 85 showed at least one metastatic LN on histology. The following parameters showed the greatest accuracy, with the best balance between specificity and sensitivity, in predicting negative LN status: cortical (C) thickness of the dominant LN (cut-off, 2.5 mm; sensitivity, 90.0%; specificity, 77.9%); short-axis (S) length of the dominant LN (cut-off, 8.4 mm; sensitivity, 63.9%; specificity, 90.6%); C/medulla (M) thickness ratio of the dominant LN (cut-off, 1.2 mm; sensitivity, 70.4%; specificity, 91.5%), the combination of S length and C/M thickness ratio (sensitivity, 88.9%; specificity, 82.4%); and the FOA analysis (sensitivity, 85.9%; specificity, 84.2%).

CONCLUSIONS

Preoperative ultrasound assessment, with or without the addition of cytology, has a high accuracy in assessing inguinal LN status in patients with vulvar cancer. In particular, the combination of two ultrasound parameters (S length and C/M thickness ratio) provided the greatest accuracy in discriminating between negative and positive LNs. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

State of the art in vulvar cancer imaging

Vulvar carcinoma is an uncommon tumor that predominantly affects postmenopausal women. Currently, there is no screening procedure for vulvar carcinoma; in most cases, it is diagnosed only when symptoms appear. The most widely used staging system is that developed by the International Federation of Gynecology and Obstetrics. Lymph node status is the most important prognostic factor. We searched the PubMed/Medline database to identify relevant English-language articles on vulvar cancer, with a special focus on its imaging evaluation. Magnetic resonance imaging is useful for local and nodal staging, as well as facilitating the planning of surgical interventions and radiotherapy. Computed tomography or positron-emission tomography/computed tomography can play an important role in nodal and distant disease assessment, whereas ultrasound is often used for image-guided biopsies. Imaging is pivotal for staging and treatment planning in vulvar carcinoma.

Female perineal diseases: spectrum of imaging findings

The female perineum, which is divided into the anterior urogenital triangle and the posterior anal triangle, is a surface structure often overlooked. Female perineal diseases may present with nonspecific clinical signs due to its close anatomical relationship between the different compartments. Diagnosis of the origin of a perineal disorder may also be a difficult problem encountered in pelvi-perineal imaging. Therefore, a precise knowledge of the female perineal anatomy and the associated disease processes is essential to radiologists, pathologists, and surgeons alike who are involved in the evaluation of the patient who presents with a perineal mass. Cross-sectional imaging plays a crucial role for proper management. Due to the robust contrast resolution of MR, MR imaging is the modality of choice for evaluation of the extent of a complex perineal lesion, its relationship to the adjacent structures. It has a greater sensitivity and specificity for the diagnosis than the other non-invasive imaging techniques and is helpful in guidance for surgical planning. The purpose of this article is to highlight the spectrum of imaging findings of female perineal diseases.

Sentinel node biopsy in vulvar cancer: Implications for staging

In 2008, the first Groningen International Study on Sentinel nodes in Vulvar cancer (GROINSS-V) showed that omission of inguinofemoral lymphadenectomy is safe in patients with early-stage vulvar cancer and a negative sentinel node and it simultaneously decreases treatment-related morbidity. An important part of the sentinel node procedure is pathologic ultrastaging of the removed sentinel nodes. Subsequently, since the introduction of this procedure in the standard care of patients with early-stage vulvar cancer, more and smaller inguinofemoral lymph node metastases have been diagnosed. The clinical consequences of these micrometastases are not clear yet. With increasing size of the sentinel node metastasis, chances of non-sentinel node metastases increase and those of survival decrease. The size of lymph node metastases is included in the latest staging system for vulvar cancer, however at this moment without clinical implications. Furthermore, a separate category for micrometastases is not incorporated yet. More research is needed to determine the clinical consequences of the size of (sentinel) lymph node metastases.