Anatomy and Imaging of Accessory Liver Lobes: What Radiologists Should Know.

Although the liver may present a range of congenital anomalies, often involving shape irregularities or the number of lobules, less common variations include the presence of accessory liver lobes (ALL), consisting of a supernumerary lobe of normal hepatic parenchyma in continuity with the liver. This paper reviews the embryology, frequency, anatomy, and types of ALL. Furthermore, we describe computed tomography and magnetic resonance imaging findings in a range of such cases, including those simulating disease or presenting with complications. Knowledge about ALL may facilitate imaging interpretation of such alterations, avoiding inappropriate additional work-up and unnecessary interventions.

Vaginal cancer: Why should we care? Anatomy, staging and in-depth imaging-based review of vaginal malignancies focusing on MRI and PET/CT.

Vaginal cancer often poses a challenge for clinical and radiological diagnosis, and its risk factors, progression, and treatment are still poorly established. Although vaginal malignancies are rare, even globally, their rates have increased due to the increased access to healthcare and the evolution of screening measures and diagnostic methods. Because the vaginal cavity is a virtual space, it can harbor lesions that often go unnoticed and, not infrequently, diagnosed belatedly. MRI and, more recently, PET/CT are part of the imaging armamentarium that have already been incorporated into the clinical staging and management of gynecological tumors, allowing excellent morphological characterization of the lesion, its topography and relationship with adjacent structures for the investigation of disease dissemination, overcoming limitations of clinical methods, such as speculum examination, usually restricted to observation only of the superficial characteristics of these lesions. Some vaginal neoplasms have characteristic MRI patterns, which, combined with expert knowledge of anatomy, allow identification of local macroscopic details (such as the mucosal, submucosal, and muscle layers). Furthermore, the application of PET/CT, already well established for identifying systemic disease, has a large impact on patient prognosis. The objective of this work is to review the epidemiological aspects of primary vaginal cancers and the imaging patterns of their main histological subtypes based on MRI and PET/CT, with a brief discussion of the local anatomy, oncological staging, and treatment.

Higher frequency of hepatic steatosis at CT among COVID-19-positive patients.

PURPOSE: Recent studies have demonstrated that obesity is significantly associated with increased disease severity, hospitalizations and mortality in COVID-19, with a potential role in the pathogenesis and prevalence in the new pandemic. The association with hepatic steatosis, however, a condition closely related to obesity within the spectrum of systemic metabolic dysfunctions, remains to be elucidated. We aimed to evaluate the frequency of hepatic steatosis as incidentally detected in chest CT examinations of COVID-19 positive patients in comparison to non-infected controls. METHODS: A retrospective study was performed with 316 patients (204 RT-PCR positive; 112 RT-PCR negative and chest CT negative). Steatosis was measured with placement of a single ROI in the right lobe of the liver (segments VI-VII) and defined as a liver attenuation value ≤ 40 HU. RESULTS: The frequency of hepatic steatosis was higher in the RT-PCR positive group in comparison to controls (31.9% vs. 7.1%, p < 0.001). Logistic linear regression analysis showed a 4.7 times odds of steatosis in the COVID-19 positive group as compared to controls after adjusting for age and sex (OR 4.698; 95% IC 2.12-10.41, p < 0.001). CONCLUSION: A significantly higher prevalence of steatosis was found among COVID-19 positive individuals. These findings are in accordance with other recent studies linking obesity and COVID-19 infection, as there is an intricate relationship between liver steatosis, metabolic syndrome and obesity. Further studies are required to confirm if such association remains after accounting for multiple variables, as well as possible relationships with disease severity and worst clinical outcomes.

The "streamline phenomenon" of the portal vein flow and its influence on liver involvement by gastrointestinal diseases: current concepts and imaging-based review.

The streamline flow in the portal system is a phenomenon by which blood from superior mesenteric vein goes preferentially to the right hepatic lobe, while splenic and inferior mesenteric veins divert preferentially to the left lobe. Such a phenomenon results in different patterns of distribution of several liver diseases. The purpose of this article is to discuss the concepts behind the theory of streamline flow and to perform an imaging-based review of representative cases, demonstrating how it may influence the patterns of liver involvement in different gastrointestinal diseases.