Ligaments and Lymphatic Pathways in Gastric Adenocarcinoma.

Gastric cancer is a leading cause of cancer-related deaths worldwide and is associated with an overall 5-year survival rate of less than 20%. The most common histologic subtype of gastric cancer is adenocarcinoma. Imaging techniques for evaluating gastric adenocarcinoma include endoscopic US, fluoroscopic upper gastrointestinal imaging, CT, PET/CT, and MRI. Hydrodynamic multiphasic contrast material-enhanced CT is the imaging modality of choice for preoperative clinical staging of regional, nodal, and metastatic involvement. Radiologic manifestations of gastric adenocarcinoma at double-contrast upper gastrointestinal imaging and CT include polyps, ulceration, indistensibility, wall thickening, and abnormal enhancement. There are multiple pathways of disease spread. These pathways include lymphatic dissemination; subperitoneal dissemination along the perigastric ligaments, mesentery, or omentum; direct invasion into adjacent organs; transperitoneal seeding; and hematogenous dissemination. The spread of disease is affected by the location of the tumor in the stomach, and the ligamentous and lymphatic anatomy. Key imaging features that affect clinical staging with use of the TNM classification system for gastric adenocarcinoma, as described in the eighth edition of the AJCC Cancer Staging Manual, are briefly discussed. Accurate radiologic assessment of gastric adenocarcinoma requires identification of perigastric ligament infiltration, regional and metastatic nodal disease, and direct and metastatic organ involvement, all of which directly affect tumor staging, treatment, and prognosis. ©RSNA, 2019.

Imaging of Emerging Infectious Diseases.

PURPOSE OF REVIEW: Emerging infectious diseases have seen a record increase in prevalence, and understanding their management is critical in an increasingly global community. In this paper, we review current literature detailing the role of radiology in the diagnosis and treatment of the Ebola (EVD), Zika (ZVD), Chikungunya (CHIKF), H1N1, Middle East Respiratory (MERS), and Severe Acute Respiratory Syndrome (SARS) viruses. RECENT FINDINGS: Complex protocols are required to safely use portable imaging in EVD to prevent nosocomial spread of disease. In ZVD, antenatal ultrasound can detect fetal abnormalities early, allowing implementation of care and support to affected families. Imaging is useful in assessing the extent of involvement of chronic CHIKF and monitoring treatment effect. Chest radiography and CT play a more direct role in the diagnosis and monitoring of the viral infections with primarily respiratory manifestations (H1N1, MERS, and SARS). SUMMARY: Radiology plays a variable role in emerging infectious diseases, requiring an understanding of disease transmission and safe imaging practices, as well as imaging features that affect clinical management.

Case Definition of Chronic Pulmonary Aspergillosis in Resource-Constrained Settings.

Chronic pulmonary aspergillosis (CPA) is a recognized complication of pulmonary tuberculosis (TB). In 2015, the World Health Organization reported 2.2 million new cases of nonbacteriologically confirmed pulmonary TB; some of these patients probably had undiagnosed CPA. In October 2016, the Global Action Fund for Fungal Infections convened an international expert panel to develop a case definition of CPA for resource-constrained settings. This panel defined CPA as illness for >3 months and all of the following: 1) weight loss, persistent cough, and/or hemoptysis; 2) chest images showing progressive cavitary infiltrates and/or a fungal ball and/or pericavitary fibrosis or infiltrates or pleural thickening; and 3) a positive Aspergillus IgG assay result or other evidence of Aspergillus infection. The proposed definition will facilitate advancements in research, practice, and policy in lower- and middle-income countries as well as in resource-constrained settings.

Neoplasms of the Appendix: Pictorial Review with Clinical and Pathologic Correlation.

Appendiceal neoplasms are uncommon tumors of the gastrointestinal tract that may manifest with symptoms of appendicitis, right lower quadrant pain, or palpable mass, leading to imaging or surgical intervention. The majority of appendiceal masses consist of primary epithelial neoplasms and neuroendocrine tumors (NETs). Epithelial neoplasms-mucinous and nonmucinous types-are more often detected at imaging than NETs due to their larger size and propensity for peritoneal spread and metastatic disease. Epithelial mucinous neoplasms are defined by the presence of mucin, detected at radiologic and pathologic examination. A mucocele or pseudomyxoma peritonei from epithelial mucinous tumors are the two most common cross-sectional imaging findings of appendiceal mucinous neoplasms. Nonmucinous epithelial tumors are less common and manifest as masses similar to colonic-type malignancies. NETs are often discovered incidentally at appendectomy due to their small size and nonaggressive behavior. Imaging findings of primary appendiceal tumors may overlap with those of acute appendicitis. Additionally, an appendiceal mass may cause acute appendicitis, obscuring the underlying mass. Other neoplasms including lymphoma, sarcoma, mesenchymal and nerve sheath tumors, or secondary malignant involvement of the appendix are rare. Treatment depends on the histologic subtype and extent of disease. Detailed description of organ, nodal, and peritoneal involvement informs surgical management with the goal of complete cytoreduction. Novel treatments such as hyperthermic intraperitoneal chemotherapy have increased survival for patients with mucinous tumors. ©RSNA, 2017.

Antibiotics-First Versus Surgery for Appendicitis: A US Pilot Randomized Controlled Trial Allowing Outpatient Antibiotic Management.

STUDY OBJECTIVE: Randomized trials suggest that nonoperative treatment of uncomplicated appendicitis with antibiotics-first is safe. No trial has evaluated outpatient treatment and no US randomized trial has been conducted, to our knowledge. This pilot study assessed feasibility of a multicenter US study comparing antibiotics-first, including outpatient management, with appendectomy. METHODS: Patients aged 5 years or older with uncomplicated appendicitis at 1 US hospital were randomized to appendectomy or intravenous ertapenem greater than or equal to 48 hours and oral cefdinir and metronidazole. Stable antibiotics-first-treated participants older than 13 years could be discharged after greater than or equal to 6-hour emergency department (ED) observation with next-day follow-up. Outcomes included 1-month major complication rate (primary) and hospital duration, pain, disability, quality of life, and hospital charges, and antibiotics-first appendectomy rate. RESULTS: Of 48 eligible patients, 30 (62.5%) consented, of whom 16 (53.3%) were randomized to antibiotics-first and 14 (46.7%) to appendectomy. Median age was 33 years (range 9 to 73 years), median WBC count was 15,000/µL (range 6,200 to 23,100/µL), and median computed tomography appendiceal diameter was 10 mm (range 7 to 18 mm). Of 15 antibiotic-treated adults, 14 (93.3%) were discharged from the ED and all had symptom resolution. At 1 month, major complications occurred in 2 appendectomy participants (14.3%; 95% confidence interval [CI] 1.8% to 42.8%) and 1 antibiotics-first participant (6.3%; 95% CI 0.2% to 30.2%). Antibiotics-first participants had less total hospital time than appendectomy participants, 16.2 versus 42.1 hours, respectively. Antibiotics-first-treated participants had less pain and disability. During median 12-month follow-up, 2 of 15 antibiotics-first-treated participants (13.3%; 95% CI 3.7% to 37.9%) developed appendicitis and 1 was treated successfully with antibiotics; 1 had appendectomy. No more major complications occurred in either group. CONCLUSION: A multicenter US trial comparing antibiotics-first to appendectomy, including outpatient management, is feasible to evaluate efficacy and safety.

Chest Radiological Findings of Patients With Severe H1N1 Pneumonia Requiring Intensive Care.

INTRODUCTION: A new strain of human influenza A (H1N1) virus originated from Mexico in 2009 and spread to more than 190 countries and territories. The World Health Organization (WHO) declared it a level 6 (highest level) pandemic. In August 2010, WHO announced that the H1N1 2009 influenza virus had moved into the postpandemic period. The WHO also declared that this flu strain is expected to continue to circulate as a seasonal virus "for some years to come." The objective of this study is to describe the chest radiographic and computed tomography (CT) findings of patients with severe H1N1 pneumonia admitted to the intensive care unit (ICU) during the 2009 pandemic. HYPOTHESIS: Patients with severe H1N1 pneumonia requiring ICU admission have extensive radiographic and CT abnormalities. METHODS: Eighteen patients, aged 23 to 62 (mean 41), admitted to the ICU at UCLA-Olive View Medical Center with a primary diagnosis of pandemic H1N1 infection, confirmed either via rapid influenza detection test or by real-time reverse transcriptase polymerase chain reaction assay, formed the study population. All patients had chest x-ray (CXR) within 24 hours of admission and 5 patients had CT examinations. In this retrospective study, images were evaluated for the pattern (ground-glass opacities, consolidation, reticular opacities, and nodular opacities), distribution (unilateral/bilateral, upper/middle/lower lung zone, and central/peripheral/peribronchovascular), and extent (focal/multifocal/diffuse; number of lung zones) of abnormalities. RESULTS: All (100%) patients had abnormal CXR and CT studies. The predominant radiographic findings were ground-glass opacities (16 of 18; 89%), consolidation (16 of 18; 89%), and reticular opacities (6 of 18, 33%). The radiographic abnormalities were bilateral in 17 (94%) patients; involved lower lung distribution in 18 (100%) patients, and mid and lower lung distribution in 16 (89%) patients. Radiographic abnormalities were peribronchovascular in 11 (61%) patients and multifocal in 10 (56%). Sixteen (89%) patients had extensive abnormalities involving 3 or more lung zones. The patients requiring mechanical ventilation had a higher incidence of bilateral, diffuse consolidation in a peribronchovascular distribution on chest radiographs. The predominant CT abnormalities were consolidation (5 of 5; 100%), ground-glass opacities (5 of 5; 100%), and nodular opacities (3 of 5, 60%). The CT findings were peribronchovascular and multifocal in 4 (80%) patients and extensive and bilateral in all (100%) patients. CONCLUSIONS: Patients with H1N1 pneumonia admitted to the ICU had bilateral, extensive CXR, and CT abnormalities. Consolidations and ground-glass opacities were the most common imaging findings, predominantly affecting mid and lower lung zones. Imaging abnormalities were peribronchovascular and multifocal in a majority of patients.

Pulmonary coccidioidomycosis: pictorial review of chest radiographic and CT findings.

Pulmonary coccidioidomycosis is a fungal disease endemic to the desert regions of the southwestern United States, Mexico, Central America, and South America. The incidence of reported disease increased substantially between 1998 and 2011, and the infection is encountered beyond the endemic areas because of a mobile society. The disease is caused by inhalation of spores of Coccidioides species. Individuals at high risk are those exposed to frequent soil aerosolization. The diagnosis is established by direct visualization of mature spherules by using special stains or cultures from biologic specimens. Serologic testing of anticoccidioidal antibodies is used for diagnosis and treatment monitoring. The infection is self-limited in 60% of cases. When the disease is symptomatic, the lung is the primary site of involvement. On the basis of clinical presentation and imaging abnormalities, pulmonary involvement is categorized into acute, disseminated, and chronic forms, each with a spectrum of imaging findings. In patients with acute disease, the most common findings are lobar or segmental consolidation, multifocal consolidation, and nodules. Adenopathy and pleural effusions are also seen, usually in association with parenchymal disease. Disseminated disease is rare and occurs in less than 1% of patients. Pulmonary findings are miliary nodules and confluent parenchymal opacities. Acute respiratory distress syndrome is an infrequent complication of disseminated disease. The acute findings resolve in most patients, with chronic changes developing in approximately 5% of patients. Manifestations of chronic disease include residual nodules, chronic cavities, persistent pneumonia with or without adenopathy, pleural effusion, and regressive changes. Unusual complications of chronic disease are mycetoma, abscess formation, and bronchopleural fistula. Patients in an immunocompromised state, those with diabetes mellitus, pregnant women, and those belonging to certain ethnic groups may show severe, progressive, or disseminated disease.