Imaging of Alcohol-Associated Liver Disease.

Alcohol-associated liver disease (ALD) continues to be a global health concern, responsible for a significant number of deaths worldwide. Although most individuals who consume alcohol do not develop ALD, heavy drinkers and binge drinkers are at increased risk. Unfortunately, ALD is often undetected until it reaches advanced stages, frequently associated with portal hypertension and hepatocellular carcinoma (HCC). ALD is now the leading indication for liver transplant. The incidence of alcohol-associated hepatitis (AH) surged during the COVID-19 pandemic. Early diagnosis of ALD is therefore important in patient management and determination of prognosis, as abstinence can halt disease progression. The spectrum of ALD includes steatosis, steatohepatitis, and cirrhosis, with steatosis the most common manifestation. Diagnostic techniques including ultrasound, CT, and MRI provide useful information for identifying ALD and excluding other causes of liver dysfunction. Heterogeneous steatosis and transient perfusion changes on CT and MRI in the clinical setting of alcohol-use disorder are diagnostic of severe AH. Elastography techniques are useful for assessing fibrosis and monitoring treatment response. These various imaging modalities are also useful in HCC surveillance and diagnosis. This review discusses the imaging modalities currently used in the evaluation of ALD, highlighting their strengths, limitations, and clinical applications.

An Unusual Presentation: High-Grade Serous Carcinoma of the Fallopian Tube Manifesting With Altered Mental Status Secondary to a Single Brain Metastasis-A Case Report and Review of the Literature.

Epithelial ovarian and fallopian cancers are aggressive lesions that rarely metastasize to the central nervous system. Brain metastases usually occur in the setting of known primary disease or widespread metastatic disease. However, in extremely rare cases, an isolated intracranial neoplasm may be the first presentation of fallopian cancer. To the best of our knowledge, only one such case has been reported previously. We present an illustrative case with multimodality imaging and histopathologic correlation of a fallopian tube carcinoma first presenting with altered mental status secondary to an isolated brain metastasis. A 64-year-old female with no pertinent medical history presented with altered mentation. Initial workup identified a 1.6 cm avidly enhancing, solitary brain lesion at the gray-white junction with associated vasogenic edema concerning for either central nervous system lymphoma or metastatic disease. Additional imaging identified a 7.5 × 3 cm left adnexal lesion, initially thought to be a hydrosalpinx with hemorrhage, but magnetic resonance imaging suggested gynecologic malignancy. No lesions elsewhere in the body were identified. Given the lack of locoregional or systemic disease, the intracranial and pelvic lesions were assumed to represent synchronous but distinct processes. The intracranial lesion was biopsied. Preliminary results were suggestive of lymphoma, but further analysis was consistent with high-grade serous carcinoma of müllerian origin. Positron emission tomography/computed tomography was performed to evaluate for other neoplastic lesions, only highlighting the intracranial and pelvic lesions. At this point, a diagnosis of metastatic fallopian cancer was made. The patient was taken for robot-assisted laparoscopy with surgical debulking of the pelvic neoplasm, pathology demonstrating high-grade serous carcinoma of the fallopian tube, matching that of the intracranial lesion. Even though rare, metastatic fallopian cancer should be considered in patients with isolated brain lesions and adnexal lesions, even in the absence of locoregional or systemic disease.

Ligament of Treitz: Anatomy, Relevance of Radiologic Findings, and Radiologic-Pathologic Correlation.

OBJECTIVE. The objective of this article is to discuss the anatomy, embryonic origin, normal variants, and various attachments of the ligament of Treitz. We also describe the pathologic processes that develop along the ligament of Treitz and the role of cross-sectional imaging in identifying these conditions. CONCLUSION. The ligament of Treitz, also known as the suspensory ligament of the duodenum, is an important anatomic landmark in the abdomen. It is essential that radiologists understand the anatomic attachments, normal variants, and various pathologic conditions involving the ligament of Treitz as well as the role of cross-sectional imaging in the assessment of these conditions.

Hepatic Mucinous Cystic Neoplasm Versus Simple Biliary Cyst: Assessment of Distinguishing Imaging Features Using CT and MRI.

OBJECTIVE. The purpose of our study was to identify the imaging features that differentiate a hepatic mucinous cystic neoplasm (MCN) from a simple biliary cyst. MATERIALS AND METHODS. Surgically resected hepatic MCNs and simple biliary cysts over a 20-year period (October 29, 1997-January 23, 2018) with preoperative CT, MRI, or both were retrospectively identified. Included cases underwent histopathologic confirmation of diagnosis based on the 2010 World Health Organization criteria and blinded imaging review. Various imaging features, including cyst shape and septal enhancement, were assessed for performance. For septate cysts, the relationship of the septation to the cyst wall-that is, arising from the wall without an indentation versus arising from an external macrolobulation-was recorded. Statistical analysis was performed for the imaging features with the chi-square test. RESULTS. The study group comprised 22 hepatic MCNs and 56 simple biliary cysts. A unilocular hepatic cystic lesion was highly predictive of a simple biliary cyst (positive predictive value = 95.2%). The imaging feature of septations arising only from macro-lobulations was 100% specific for a simple biliary cyst on CT (p = 0.001). The presence of septations arising from the cyst wall without indentation was 100% sensitive for hepatic MCN but was only 56.3% specific on CT. Septal enhancement reached 100% sensitivity for hepatic MCN on MRI (p = 0.018). CONCLUSION. The presence of septations, relationship of the septations to the cyst wall, and septal enhancement were sensitive imaging features in the detection of hepatic MCN. The imaging feature of septations arising only from macrolobulations in the cyst wall was specific for simple biliary cysts on CT and helped differentiate simple biliary cysts from hepatic MCNs.

Human Gut Microbiota-associated Gastrointestinal Malignancies: A Comprehensive Review.

The human gastrointestinal tract houses trillions of microbes. The gut and various types of microorganisms, including bacteria, viruses, fungi, and archaea, form a complex ecosystem known as the gut microbiota, and the whole genome of the gut microbiota is referred to as the gut microbiome. The gut microbiota is essential for homeostasis and the overall well-being of a person and is increasingly considered an adjunct "virtual organ," with a complexity level comparable to that of the other organ systems. The gut microbiota plays an essential role in nutrition, local mucosal homeostasis, inflammation, and the mucosal immune system. An imbalanced state of the gut microbiota, known as dysbiosis, can predispose to development of various gastrointestinal malignancies through three speculated pathogenic mechanisms: (a) direct cytotoxic effects with damage to the host DNA, (b) disproportionate proinflammatory signaling inducing inflammation, and (c) activation of tumorigenic pathways or suppression of tumor-suppressing pathways. Several microorganisms, including Helicobacter pylori, Epstein-Barr virus, human papillomavirus, Mycoplasma species, Escherichia coli, and Streptococcus bovis, are associated with gastrointestinal malignancies such as esophageal adenocarcinoma, gastric adenocarcinoma, gastric mucosa-associated lymphoid tissue lymphoma, colorectal adenocarcinoma, and anal squamous cell carcinoma. Imaging plays a pivotal role in diagnosis and management of microbiota-associated gastrointestinal malignancies. Appropriate use of probiotics, fecal microbiota transplantation, and overall promotion of the healthy gut are ongoing areas of research for prevention and treatment of malignancies. Online supplemental material is available for this article. ©RSNA, 2021.

Imaging Manifestations of Genitourinary Tuberculosis.

The genitourinary region is one of the most common sites of extrapulmonary tuberculosis (TB) involvement. The imaging features of genitourinary TB are protean and can mimic other entities, including malignancy, and pose a diagnostic dilemma. Hematogenous seeding and lymphatic spread of mycobacteria from pulmonary, tonsillar, and nodal TB are implicated in the pathogenesis of genitourinary TB. In addition, contiguous extension from the urinary tract and sexual transmission are described as sources of genital TB. Genitourinary TB can be indolent and results in nonspecific signs and symptoms; thus, imaging has a vital role in the working diagnosis for these cases. Classic uroradiologic signs of genitourinary TB are primarily described from the era of intravenous urography and conventional radiography. Now, CT, CT urography, MRI, and US are used in the diagnosis and management. Familiarity with the imaging features of genitourinary TB may help guide the diagnosis and, in turn, lead to timely management. US has a vital role in the evaluation of scrotal and female genital TB. MRI offers superior soft-tissue contrast resolution and excellent depiction of anatomic detail. The various imaging manifestations of genitourinary TB are highlighted. ©RSNA, 2021.

Second Malignancies after Radiation Therapy: Update on Pathogenesis and Cross-sectional Imaging Findings.

A wide spectrum of second cancers occur as late complications of radiation therapy (RT) used to treat various malignancies. In addition to the type and dose of radiation, lifestyle, environmental, and genetic factors are important to the development of second malignancies in cancer survivors. Typically, RT-induced malignancies (RTIMs) are biologically aggressive cancers with a variable period of 5-10 years for hematologic malignancies and 10-60 years for solid tumors between RT and the development of the second cancer. Although carcinomas and leukemias commonly develop after low-dose RT, sarcomas occur in tissues or organs that receive high-dose RT. Angiosarcomas and unclassified pleomorphic sarcomas are the two most common RT-associated sarcomas; other sarcomas include malignant peripheral nerve sheath tumors, leiomyosarcomas, osteosarcomas, chondrosarcomas, and dedifferentiated or pleomorphic liposarcomas. Select RTIMs show tumor genetic characteristics that allow accurate diagnosis. Nearly all cutaneous angiosarcomas after RT for breast cancer and 90% of RT-associated malignant peripheral nerve sheath tumors are characterized by MYC gene amplifications and loss of H3 K27me3 expression, respectively. Classic papillary thyroid carcinomas that develop after RT frequently harbor RET/PTC rearrangements and have a favorable prognosis, despite their advanced stage at patient presentation. Select RTIMs demonstrate characteristic imaging findings and typically develop in the prior radiation field. Imaging is essential to early diagnosis, characterization, localization, and staging of RTIMs. Familiarity of radiologists with the diverse spectrum of RTIMs is essential for early diagnosis and optimal management. An invited commentary by Shapiro is available online. ©RSNA, 2021.

Imaging Spectrum of Granulomatous Diseases of the Abdomen and Pelvis.

A granuloma is a compact organization of mature macrophages that forms because of persistent antigenic stimulation. At the microscopic level, granulomas can undergo various morphologic changes, ranging from necrosis to fibrosis, which along with other specialized immune cells define the appearance of the granulomatous process. Accordingly, the imaging features of granulomatous diseases vary and can overlap with those of other diseases, such as malignancy, and lead to surgical excisions and biopsy. However, given the heterogeneity of granulomas as a disease group, it is often hard to make a diagnosis on the basis of the histopathologic features of granulomatous diseases alone owing to overlapping microscopic features. Instead, a multidisciplinary approach is often helpful. Radiologists need to be familiar with the salient clinical manifestations and imaging findings of granulomatous diseases to generate an appropriate differential diagnosis. ©RSNA, 2021.

Pancreas in Hereditary Syndromes: Cross-sectional Imaging Spectrum.

A wide spectrum of hereditary syndromes predispose patients to distinct pancreatic abnormalities, including cystic lesions, recurrent pancreatitis, ductal adenocarcinoma, nonductal neoplasms, and parenchymal iron deposition. While pancreatic exocrine insufficiency and recurrent pancreatitis are common manifestations in cystic fibrosis and hereditary pancreatitis, pancreatic cysts are seen in von Hippel-Lindau disease, cystic fibrosis, autosomal dominant polycystic kidney disease, and McCune-Albright syndrome. Ductal adenocarcinoma can be seen in many syndromes, including Peutz-Jeghers syndrome, familial atypical multiple mole melanoma syndrome, Lynch syndrome, hereditary breast and ovarian cancer syndrome, Li-Fraumeni syndrome, and familial pancreatic cancer syndrome. Neuroendocrine tumors are commonly seen in multiple endocrine neoplasia type 1 syndrome and von Hippel-Lindau disease. Pancreatoblastoma is an essential component of Beckwith-Wiedemann syndrome. Primary hemochromatosis is characterized by pancreatic iron deposition. Pancreatic pathologic conditions associated with genetic syndromes exhibit characteristic imaging findings. Imaging plays a pivotal role in early detection of these conditions and can positively affect the clinical outcomes of those at risk for pancreatic malignancies. Awareness of the characteristic imaging features, imaging-based screening protocols, and surveillance guidelines is crucial for radiologists to guide appropriate patient management. ©RSNA, 2021.

Magnetic resonance imaging features in 283 patients with primary biliary cholangitis.

OBJECTIVES: To evaluate magnetic resonance imaging (MRI) features of the liver in primary biliary cholangitis (PBC). METHODS: We conducted a multicenter retrospective review on 283 patients with PBC who underwent an MRI between 2007 and 2018. Patients with overlap syndromes were excluded. MRI studies were independently reviewed by two abdominal radiologists for liver morphology, signal intensity, postcontrast enhancement, and decompensation. Liver and spleen volumes and normalized liver apparent diffusion coefficient (nlADC) were also calculated. MRI features were correlated with fibrosis stage among a subset of patients who had a liver biopsy within 6 months (n = 72). RESULTS: The study population was comprised of 283 patients (89% females) and a mean ± SD age of 59.4 ± 11.8 years. Lymphadenopathy (78.1%), periportal hyperintensity (36.7%), and periportal halo sign (27.6%) were the most common features. A positive correlation was found between fibrosis stage and spleen size (r = 0.457, p < 0.001), spleen volume (r = 0.557, p < 0.001) and portal vein diameter (r = 0.287, p = 0.013), and a negative correlation with nlADC (r = - 0.332, p = 0.011). Fibrosis stage also correlated with the presence of surface nodularity (p < 0.001), periportal halo sign (p = 0.04), collaterals (p = 0.033), and splenomegaly (p = 0.002). No significant differences in nlADC values were found in different fibrosis stages. Spleen size and volume were significantly higher in patients with ascites and collaterals (< 0.001). The periportal halo sign was present only in patients with significant fibrosis. None of the MRI features significantly correlated with inflammation grade. CONCLUSIONS: In PBC, presence of periportal halo sign correlates with significant fibrosis. Heterogeneous T2W intensity, heterogeneous postcontrast enhancement, collaterals, spleen size, and spleen volume correlate with fibrosis stage and may be useful for predicting advanced fibrosis. KEY POINTS: • The presence of periportal halo sign is indicative for significant fibrosis in primary biliary cholangitis. • Liver parenchymal heterogeneous T2 signal intensity, heterogeneous postcontrast enhancement, collaterals, spleen size, and spleen volume correlate with fibrosis stages in PBC and may be useful for predicting advanced fibrosis.

The Lesser Sac and Foramen of Winslow: Anatomy, Embryology, and CT Appearance of Pathologic Processes.

OBJECTIVE. This article reviews the embryologic development, relevant anatomy, and imaging features, on CT, of pathologic processes involving the lesser sac and foramen of Winslow. CONCLUSION. The lesser peritoneal sac is an intricate anatomic region involved in many disease processes. It is a significant conduit for the spread of disease within the peritoneal cavity. The spectrum of pathologic processes pertaining to the lesser sac can be classified on the basis of the type of involvement, such as a fluid collection (e.g., transudate, exudate, bile, and blood), a mass (e.g., neoplastic or nonneoplastic conditions and lymphadenopathy), or an internal hernia into the lesser sac.

Multiple Endocrine Neoplasia: Spectrum of Abdominal Manifestations.

OBJECTIVE. Multiple endocrine neoplasia (MEN) syndromes are autosomal-dominant genetic disorders that predispose two or more organs of the endocrine system to tumor development. Although the diagnosis relies on clinical and serologic findings, imaging provides critical information for surgical management with the ultimate goal of complete tumor resection. CONCLUSION. This article reviews abdominal neoplasms associated with the various subtypes of MEN syndromes, with a focus on clinical presentation and characteristic imaging features.

A Review of Viral-Related Malignancies and the Associated Imaging Findings.

OBJECTIVE. Imaging plays an important role in the diagnosis and staging of malignancies. Many common lymphoproliferative and other solid tumor malignancies can be viral-related. CONCLUSION. This review discusses the imaging findings that can be associated with common viral-induced malignancies. Knowledge of these imaging presentations can help narrow the differential diagnosis to reach a specific diagnosis through a precise workup and proper management.

Calcified Splenic Lesions: Pattern Recognition Approach on CT With Pathologic Correlation.

OBJECTIVE. Incidental splenic lesions, often found on CT images of the abdomen, may often be ignored or mischaracterized. Calcified splenic lesions are often presumed to be granulomas; however, understanding the broader differential diagnostic considerations can be useful. CONCLUSION. Determining the cause of splenic lesions is essential to guide appropriate management; the pattern of calcification together with other imaging and clinical findings can aid with differentiation.

Abdominal Imaging Manifestations of Recreational Drug Use.

Recreational drug use is a burgeoning health issue worldwide, with a variety of presenting symptoms and complications. These complications can be secondary to the toxic effects of the drug itself, drug impurities, and nonsterile injection. The abdominal radiologist is likely to encounter patients who use drugs recreationally and may be responsible for recognizing and reporting these acute conditions, which in some cases can be life threatening. Because these patients often present with an altered mental state and may deny or withhold information on drug use, the underlying cause may be difficult to determine. The most commonly used drugs worldwide include cocaine, cannabinoids, opioids, and amphetamines and their derivatives. Complications of use of these drugs that can be seen at abdominopelvic CT can involve multiple organ systems, including the soft tissue and gastrointestinal, genitourinary, vascular, and musculoskeletal systems. A diverse range of abdominal complications associated with these drugs can be seen at imaging, including disseminated infections, gastrointestinal ischemia, and visceral infarction. Radiologists should be familiar with the imaging findings of these complications to accurately diagnose these entities and help guide workup and patient treatment. ©RSNA, 2020.

Imaging Evaluation of Fallopian Tubes and Related Disease: A Primer for Radiologists.

A wide range of benign and malignant processes can affect one or both fallopian tubes. Familiarity with and recognition of the characteristic imaging features of these diseases and conditions are imperative for accurate diagnosis and prompt patient management. Disorders including pelvic inflammatory disease (hydrosalpinx and pyosalpinx in particular), isolated tubal torsion and ovarian torsion with fallopian tube involvement, endometriosis manifesting as hematosalpinx and adhesions, ectopic pregnancy, and malignancies are the most important entities that radiologists should be familiar with when assessing the fallopian tubes. Some fallopian tube diseases are self-limiting, while others can result in infertility or even potentially life-threatening infection or bleeding if left untreated. Therefore, correct diagnosis is important for appropriate life-saving treatment and preserving fertility. Understanding the physiologic features of the fallopian tube and the role of this organ in the pathogenesis of pelvic neoplasms is equally important. Knowledge of what to expect in a patient who has undergone uterine and fallopian tube interventions, such as uterine ablation and fallopian tube ligation, and of the potential associated complications (eg, postablation sterilization syndrome) also is pertinent. The imaging modalities used for the evaluation of fallopian tube disease and patency range from commonly used examinations such as US, CT, and MRI to other modalities such as hysterosalpingography and hysterosonography performed by using US contrast material. The ability to differentiate fallopian tube conditions from other adnexal and pelvic pathologic entities by using a variety of imaging modalities allows the radiologist to make a timely diagnosis and ensure proper clinical management. Online supplemental material is available for this article. ©RSNA, 2020.

Decoding Genes: Current Update on Radiogenomics of Select Abdominal Malignancies.

Technologic advances in chromosomal analysis and DNA sequencing have enabled genome-wide analysis of cancer cells, yielding considerable data on the genetic basis of malignancies. Evolving knowledge of tumor genetics and oncologic pathways has led to a better understanding of histopathologic features, tumor classification, tumor biologic characteristics, and imaging findings and discovery of targeted therapeutic agents. Radiogenomics is a rapidly evolving field of imaging research aimed at correlating imaging features with gene mutations and gene expression patterns, and it may provide surrogate imaging biomarkers that may supplant genetic tests and be used to predict treatment response and prognosis and guide personalized treatment options. Multidetector CT, multiparametric MRI, and PET with use of multiple radiotracers are some of the imaging techniques commonly used to assess radiogenomic associations. Select abdominal malignancies demonstrate characteristic imaging features that correspond to gene mutations. Recent advances have enabled us to understand the genetics of steatotic and nonsteatotic hepatocellular adenomas, a plethora of morphologic-molecular subtypes of hepatic malignancies, a variety of clear cell and non-clear cell renal cell carcinomas, a myriad of hereditary and sporadic exocrine and neuroendocrine tumors of the pancreas, and the development of targeted therapeutic agents for gastrointestinal stromal tumors based on characteristic KIT gene mutations. Mutations associated with aggressive phenotypes of these malignancies can sometimes be predicted on the basis of their imaging characteristics. Radiologists should be familiar with the genetics and pathogenesis of common cancers that have associated imaging biomarkers, which can help them be integral members of the cancer management team and guide clinicians and pathologists. Online supplemental material is available for this article. ©RSNA, 2020 See discussion on this article by Luna (pp 1627-1630).

Imaging Evaluation of Abdominopelvic Gunshot Trauma.

Firearm-related injuries, or gunshot wounds (GSWs), are among the most important worldwide public health problems, resulting in considerable annual morbidity, disability, and mortality. GSWs to the abdomen and pelvis are associated with substantial injuries to multiple organs and tissues. Imaging plays an important role in identifying these injuries, dictating nonoperative management, and determining imaging and clinical follow-up, as well as helping manage potential long-term complications. CT is the primary imaging modality used to evaluate these injuries and their complications, including use of reconstructed multiplanar volume-rendered images. The authors discuss the ballistics and mechanisms of firearm injury, CT findings, trajectory analysis, and applications of different imaging modalities above and beyond CT in evaluation of GSWs. Imaging findings and classifications of the severity of injuries to solid and hollow organs and vascular, musculoskeletal, and neurologic systems are reviewed. Key complications associated with gunshot injuries to the abdomen and pelvis are presented. The challenges of imaging in the acute trauma setting and potential pitfall mimics at imaging, particularly at CT, are also described. A step-by-step guide for thorough and comprehensive evaluation of GSWs to the abdomen and pelvis is introduced, with tips for optimizing effective communication with the clinical team. Online supplemental material is available for this article. ©RSNA, 2020.

RadioGraphics Update: Venous Thrombosis and Hypercoagulability in the Abdomen and Pelvis-Findings in COVID-19.

Editor's Note.-Articles in the RadioGraphics Update section provide current knowledge to supplement or update information found in full-length articles previously published in RadioGraphics. Authors of the previously published article provide a brief synopsis that emphasizes important new information such as technological advances, revised imaging protocols, new clinical guidelines involving imaging, or updated classification schemes. Articles in this section are published solely online and are linked to the original article.

Venous Thrombosis and Hypercoagulability in the Abdomen and Pelvis: Causes and Imaging Findings.

Venous thromboembolism (VTE), which includes deep venous thrombosis and pulmonary embolism, is a significant cause of morbidity and mortality. In recent decades, US, CT, and MRI have surpassed catheter-based angiography as the imaging examinations of choice for evaluation of vascular structures and identification of thrombus owing to their ready availability, noninvasive nature, and, in the cases of US and MRI, lack of exposure to ionizing radiation. As a result, VTE and associated complications are commonly identified in day-to-day radiologic practice across a variety of clinical settings. A wide range of hereditary and acquired conditions can increase the risk for development of venous thrombosis, and many patients with these conditions may undergo imaging for unrelated reasons, leading to the incidental detection of VTE or one of the associated complications. Although the development of VTE may be an isolated occurrence, the imaging findings, in conjunction with the clinical history and vascular risk factors, may indicate a predisposing condition or underlying diagnosis. Furthermore, awareness of the many clinical conditions that result in an increased risk of venous thrombosis may aid in detection of thrombus and any concomitant complications. For these reasons, it is important that practicing radiologists be familiar with the multimodality imaging findings of thrombosis, understand the spectrum of diseases that contribute to the development of thrombosis, and recognize the potential complications of hypercoagulable states and venous thrombosis. Online DICOM image stacks and supplemental material are available for this article. ©RSNA, 2020.