Imaging of Antepartum and Postpartum Hemorrhage.

Severe obstetric hemorrhage is a leading cause of maternal mortality and morbidity worldwide. Major hemorrhage in the antepartum period presents potential risks for both the mother and the fetus. Similarly, postpartum hemorrhage (PPH) accounts for up to a quarter of maternal deaths worldwide. Potential causes of severe antepartum hemorrhage that radiologists should be familiar with include placental abruption, placenta previa, placenta accreta spectrum disorders, and vasa previa. Common causes of PPH that the authors discuss include uterine atony, puerperal genital hematomas, uterine rupture and dehiscence, retained products of conception, and vascular anomalies. Bleeding complications unique to or most frequently encountered after cesarean delivery are also enumerated, including entities such as bladder flap hematomas, rectus sheath and subfascial hemorrhage, and infectious complications of endometritis and uterine dehiscence. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material. See the invited commentary by Javitt and Madrazo in this issue.

Image-Guided Radiotherapy for Gynecologic Malignancies: What the Radiologist Needs to Know.

Pelvic imaging is integral to contemporary radiotherapy (RT) management of gynecologic malignancies. For cervical, endometrial, vulvar, and vaginal cancers, three-dimensional imaging modalities aid in tumor staging and RT candidate selection and inform treatment strategy, including RT planning, execution, and posttherapy surveillance. State-of-the-art care routinely incorporates magnetic resonance (MR) imaging, 18F-fluorodeoxyglucose-PET/computed tomography (CT), and CT to guide external beam RT and brachytherapy, allowing the customization of RT plans to maximize patient outcomes and reduce treatment-related toxicities. Follow-up imaging identifies radiation-resistant and recurrent disease as well as short-term and long-term toxicities from RT.

A primer on rectal MRI in patients on watch-and-wait treatment for rectal cancer.

Total neoadjuvant treatment (TNT) for rectal cancer is becoming an accepted treatment paradigm and is changing the landscape of this disease, wherein up to 50% of patients who undergo TNT are able to avoid surgery. This places new demands on the radiologist in terms of interpreting degrees of response to treatment. This primer summarizes the Watch-and-Wait approach and the role of imaging, with illustrative "atlas-like" examples as an educational guide for radiologists. We present a brief literature summary of the evolution of rectal cancer treatment, with a focus on magnetic resonance imaging (MRI) assessment of response. We also discuss recommended guidelines and standards. We outline the common TNT approach entering mainstream practice. A heuristic and algorithmic approach to MRI interpretation is also offered. To illustrate management and common scenarios, we arranged the illustrative figures as follows: (I) Clinical complete response (cCR) achieved at the immediate post-TNT "decision point" scan time; (II) cCR achieved at some point during surveillance, later than the first post-TNT MRI; (III) near clinical complete response (nCR); (IV) incomplete clinical response (iCR); (V) discordant findings between MRI and endoscopy where MRI is falsely positive, even at follow-up; (VI) discordant cases where MRI seems to be falsely positive but is proven truly positive on follow-up endoscopy; (VII) cases where MRI is falsely negative; (VIII) regrowth of tumor in the primary tumor bed; (IX) regrowth outside the primary tumor bed; and (X) challenging scenarios, i.e., mucinous cases. This primer is offered to achieve its intended goal of educating radiologists on how to interpret MRI in patients with rectal cancer undergoing treatment using a TNT-type treatment paradigm and a Watch-and-Wait approach.

Mimics of cancer in pregnancy.

Pregnancy is a remarkable time of pronounced growth and development of the fetus. Benign pathologies outside of the uterus, including those containing hormonally responsive tissue which undergo physiologic changes and other incidentally identified lesions, may mimic malignancy on clinical evaluation and imaging. A detailed history and physical exam, ultrasound and non-contrast magnetic resonance imaging features and comparison with prior imaging if available may help to narrow the list of potential differential diagnoses. Follow-up imaging in the postpartum period is often vital to confirm benignity and, in some cases, sampling to confirm the diagnosis is necessary. This review will cover the clinical, pathological and multimodality imaging features of numerous potential mimickers of cancer in the setting of pregnancy organized by organ systems. The goal is to better equip abdominal radiologists to accurately identify benign disease and help guide further imaging or follow-up recommendations to avoid unnecessarily aggressive intervention and improve patient care.

Update on MRI in Evaluation and Treatment of Endometrial Cancer.

Endometrial cancer is the second most common gynecologic cancer worldwide and the most common gynecologic cancer in the United States, with an increasing incidence in high-income countries. Although the International Federation of Gynecology and Obstetrics (FIGO) staging system for endometrial cancer is a surgical staging system, contemporary published evidence-based data and expert opinions recommend MRI for treatment planning as it provides critical diagnostic information on tumor size and depth, extent of myometrial and cervical invasion, extrauterine extent, and lymph node status, all of which are essential in choosing the most appropriate therapy. Multiparametric MRI using a combination of T2-weighted sequences, diffusion-weighted imaging, and multiphase contrast-enhanced imaging is the mainstay for imaging assessment of endometrial cancer. Identification of important prognostic factors at MRI improves both treatment selection and posttreatment follow-up. MRI also plays a crucial role for fertility-preserving strategies and in patients who are not surgical candidates by helping guide therapy and identify procedural complications. This review is a product of the Society of Abdominal Radiology Uterine and Ovarian Cancer Disease-Focused Panel and reflects a multidisciplinary international collaborative effort to summarize updated information highlighting the role of MRI for endometrial cancer depiction and delineation, treatment planning, and follow-up. The article includes information regarding dedicated MRI protocols, tips for MRI reporting, imaging pitfalls, and strategies for image quality optimization. The roles of MRI-guided radiation therapy, hybrid PET/MRI, and advanced MRI techniques that are applicable to endometrial cancer imaging are also discussed. Online supplemental material is available for this article. ©RSNA, 2022.

Update on MR Contrast Agents for Liver Imaging: What to Use and When.

Contrast-enhanced liver MR imaging is an important diagnostic tool for many different liver diseases with the sensitivity and specificity in diagnosing liver diseases typically far exceeding other imaging modalities. The safety profile of GBCA is excellent with minimal adverse events. Both extracellular and hepatobiliary contrast agents offer unique advantages and potential limitations. ECA is excellent for obtaining high-quality arterial phase imaging and can be particularly useful for the evaluation of hepatocellular carcinoma (HCC) in cirrhotic patients. In contrast, hepatobiliary agent (HBA) can help distinguish FNH from adenomas, detect liver metastases, and provide biliary imaging due to their uptake within normal hepatocytes and biliary excretion.

Tumor in vein (LR-TIV) and liver imaging reporting and data system (LI-RADS) v2018: diagnostic features, pitfalls, prognostic and management implications.

Vascular invasion by hepatocellular carcinoma (HCC), also known as tumor in vein (TIV), indicates highly invasive tumor behavior and is also associated with poor outcome. Because a diagnosis of TIV precludes liver transplantation, knowledge of the imaging findings to differentiate between TIV and bland thrombus is key for proper patient management. Prior versions of liver imaging reporting and data system (LI-RADS) included presence of TIV as part of LR-5 criteria. However, even if HCC is the most common liver malignancy associated with TIV, other tumors can have vascular invasion and may occur in cirrhotic patients. For these reasons, in LI-RADS v2017 LR-TIV has been introduced as a new different diagnostic category. The aim of this article is to discuss the diagnostic criteria of LR-TIV according to LI-RADS v2018 and analyze potential pitfalls encountered on daily clinical practice. Indeterminate cases and how to manage them will also be discussed.

Sonography of liver transplantation.

Orthotopic liver transplant (OLT) is established as the definitive treatment of choice for end stage liver disease. Over the years, refined surgical techniques as well as advancements in organ preservation and immunosuppressive regimens have improved graft and patient survival rates. Imaging has also contributed to improved graft and patient survival. Ultrasound is the initial investigation of choice for evaluation of post-transplant anatomy and for identifying early complications. A thorough knowledge of surgical techniques and normal post-operative appearance of the OLT is needed to accurately identify and characterize graft complications. The objective of this article is to review the sonographic findings of normal liver transplant as well as post-operative complications. Indications and contraindications for OLT as well as different surgical techniques will also be briefly reviewed.

Split-bolus MDCT urography: Upper tract opacification and performance for upper tract tumors in patients with hematuria.

OBJECTIVE: Our purpose was to assess upper urinary tract opacification and the performance of split-bolus MDCT urography for upper tract tumors in patients with hematuria. MATERIALS AND METHODS: Between January 2004 and December 2006, we identified 200 patients (119 men, 81 women; median age, 58 years, age range, 18-89 years) who underwent MDCT urography for hematuria. MDCT urography included unenhanced and combined nephrographic and excretory phase imaging of the urinary tract. Images were independently reviewed by two radiologists blinded to the final diagnosis. The degree of upper urinary tract opacification and the diagnosis were recorded. Prospective interpretations were also reviewed. The standard of reference included all available clinical, imaging, and laboratory data for up to 12 months after MDCT urography. Sensitivity, specificity, accuracy, and positive and negative predictive values were calculated for upper tract tumors for prospective and retrospective interpretations. RESULTS: For reviewers 1 and 2, 85.1% and 84.5% of segments were at least 50% opacified, respectively. Final diagnoses for hematuria were no cause, 123 (61.5%); urothelial cancer, 27 (13.5%); nonmalignant, 46 (23%) and indeterminate, four patients (2%). There were nine upper tract cancers. Sensitivity, specificity, and accuracy for upper tract cancers for prospective interpretation, reviewer 1 and reviewer 2, were 100%, 99%, 99%; 100%, 99.5%, 99.5%; and 88.9%, 99.0%, 98.5%, respectively. CONCLUSION: Split-bolus MDCT urography provided at least 50% opacification of the majority of upper urinary tract segments and had high sensitivity, specificity, and accuracy for the detection of upper urinary tract tumors.