Advanced Imaging Techniques in Evaluation of Colorectal Cancer.

Imaging techniques are clinical decision-making tools in the evaluation of patients with colorectal cancer (CRC). The aim of this article is to discuss the potential of recent advances in imaging for diagnosis, prognosis, therapy planning, and assessment of response to treatment of CRC. Recent developments and new clinical applications of conventional imaging techniques such as virtual colonoscopy, dual-energy spectral computed tomography, elastography, advanced computing techniques (including volumetric rendering techniques and machine learning), magnetic resonance (MR) imaging-based magnetization transfer, and new liver imaging techniques, which may offer additional clinical information in patients with CRC, are summarized. In addition, the clinical value of functional and molecular imaging techniques such as diffusion-weighted MR imaging, dynamic contrast material-enhanced imaging, blood oxygen level-dependent imaging, lymphography with contrast agents, positron emission tomography with different radiotracers, and MR spectroscopy is reviewed, and the advantages and disadvantages of these modalities are evaluated. Finally, the future role of imaging-based analysis of tumor heterogeneity and multiparametric imaging, the development of radiomics and radiogenomics, and future challenges for imaging of patients with CRC are discussed. Online supplemental material is available for this article. ©RSNA, 2018.

IgG4-related Disease from Head to Toe.

Immunoglobulin G4 (IgG4)-related disease is a relatively recently proposed clinical-pathologic entity that is characterized by fibro-inflammatory lesions rich in IgG4-positive plasma cells and, often but not always, elevated serum IgG4 concentrations. IgG4-related disease was recognized as a systemic disease in 2003, when extrapancreatic manifestations were identified in patients with autoimmune pancreatitis. Since then, the disease has been reported as affecting virtually every organ system and has been identified in the biliary tree, salivary and lacrimal glands, periorbital tissues, lungs, lymph nodes, thyroid gland, kidneys, prostate gland, testicles, breasts, and pituitary gland. Its pathogenesis is poorly understood, but findings are consistent with both an autoimmune and an allergic disorder. Although definitive diagnosis requires histopathologic analysis, imaging plays an important role in demonstrating infiltration and enlargement of involved organs. Because of the systemic nature of the disease, imaging workup of IgG4-related disease should always include whole-body examinations to detect multiorgan involvement. Patients often present with subacute development of a mass in or diffuse enlargement of the affected organ, sometimes mimicking a neoplastic process. In every anatomic location, several inflammatory and neoplastic entities must be considered in the differential diagnosis. Because IgG4-related disease usually shows a marked response to corticosteroid therapy, radiologists should be familiar with its clinical and imaging manifestations to avoid a delay in diagnosis and unnecessary surgical interventions.

Development of prognostic models to estimate the probability of lung injury one year after COVID-19-related hospitalization-a prospective study.

Background: Long-term effects of severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) infection still under study. The objectives of this study were to identify persistent pulmonary lesions 1 year after coronavirus disease 2019 (COVID-19) hospitalization and assess whether it is possible to estimate the probability that a patient develops these complications in the future. Methods: A prospective study of ≥18 years old patients hospitalized for SARS-COV-2 infection who develop persistent respiratory symptoms, lung function abnormalities or have radiological findings 6-8 weeks after hospital discharge. Logistic regression models were used to identify prognostic factors associated with a higher risk of developing respiratory problems. Models performance was assessed in terms of calibration and discrimination. Results: A total of 233 patients [median age 66 years [interquartile range (IQR): 56, 74]; 138 (59.2%) male] were categorized into two groups based on whether they stayed in the critical care unit (79 cases) or not (154). At the end of follow-up, 179 patients (76.8%) developed persistent respiratory symptoms, and 22 patients (9.4%) showed radiological fibrotic lesions with pulmonary function abnormalities (post-COVID-19 fibrotic pulmonary lesions). Our prognostic models created to predict persistent respiratory symptoms [post-COVID-19 functional status at initial visit (the higher the score, the higher the risk), and history of bronchial asthma] and post-COVID-19 fibrotic pulmonary lesions [female; FVC% (the higher the FVC%, the lower the probability); and critical care unit stay] one year after infection showed good (AUC 0.857; 95% CI: 0.799-0.915) and excellent performance (AUC 0.901; 95% CI: 0.837-0.964), respectively. Conclusions: Constructed models show good performance in identifying patients at risk of developing lung injury one year after COVID-19-related hospitalization.

Intussusception in adults: what radiologists should know.

Adult intussusception (AI) is a rare entity with an organic lesion within the intussusception in 70-90% of the cases. Intussusception is classified according to location, etiology, and to the presence or not of a lead point. We illustrate several causes of AI with a variety of radiological findings on plain film, ultrasonography, computed tomography, magnetic resonance, and endoscopy seen at our institution. Imaging plays a major role in their diagnosis and in determining the appropriate treatment.

A few-shot approach for COVID-19 screening in standard and portable chest X-ray images.

Reliable and effective diagnostic systems are of vital importance for COVID-19, specifically for triage and screening procedures. In this work, a fully automatic diagnostic system based on chest X-ray images (CXR) has been proposed. It relies on the few-shot paradigm, which allows to work with small databases. Furthermore, three components have been added to improve the diagnosis performance: (1) a region proposal network which makes the system focus on the lungs; (2) a novel cost function which adds expert knowledge by giving specific penalties to each misdiagnosis; and (3) an ensembling procedure integrating multiple image comparisons to produce more reliable diagnoses. Moreover, the COVID-SC dataset has been introduced, comprising almost 1100 AnteroPosterior CXR images, namely 439 negative and 653 positive according to the RT-PCR test. Expert radiologists divided the negative images into three categories (normal lungs, COVID-related diseases, and other diseases) and the positive images into four severity levels. This entails the most complete COVID-19 dataset in terms of patient diversity. The proposed system has been compared with state-of-the-art methods in the COVIDGR-1.0 public database, achieving the highest accuracy (81.13% ± 2.76%) and the most robust results. An ablation study proved that each system component contributes to improve the overall performance. The procedure has also been validated on the COVID-SC dataset under different scenarios, with accuracies ranging from 70.81 to 87.40%. In conclusion, our proposal provides a good accuracy appropriate for the early detection of COVID-19.

Pleuroparenchymal fibroelastosis: Clinical, radiological and histopathological features.

Pleuroparenchymal fibroelastosis (PPFE) is a rare, generally idiopathic form of interstitial pneumonia with unique clinical, radiological and histopathological features. It is named after the presence of upper lobe pleural and subjacent parenchymal fibrosis, with accompanying elastic fibers. Although it is usually an idiopathic disease, it has been linked to other co-existent diseases. Diagnostic suspicion of PPFE is based on the identification of typical abnormalities on chest CT scan, which are prevailingly located in the upper lobes, adjacent to the apex of the lungs. Diagnosis can be confirmed by histological analysis, although biopsy is not always feasible. The disease is generally progressive, but not uniformly. The course of the disease is frequently slow and involves a progressive loss of upper lobe volume, which results in platythorax, associated with a significant reduction of body mass. PPFE concomitant to other interstitial lung diseases is associated with a poorer prognosis. The disease occasionally progresses rapidly causing irreversible respiratory insufficiency, which leads to death. Currently, there is no effective pharmacological therapy available, and lung transplantation is the best therapeutic option. The purpose of this review is to draw the attention to PPFE, describe its clinical, radiological and histopathological features, analyze its diagnostic criteria, and provide an update on the management of the disease.

Usefulness of Positron Emission Tomography in the Examination of Hilar and Mediastinal Lymphadenopathies in Patients with Suspicion of Lung Cancer.

Introduction: Lung cancer is a major health problem. Mediastinal staging performed with the aid of imaging techniques is essential for appropriate disease treatment and prognosis. Accordingly, this study aimed to ascertain the usefulness of positron emission tomography (PET) in mediastinal staging, establish the best maximum standardized uptake value (SUVmax) cutoff point, compare its usefulness to that of computed tomography (CT), and determine the influence of histological tumour subtype. Methods: We conducted a retrospective study across a period of 3 years on 128 patients with suspicion of lung cancer and analyzed their demographic and radiological characteristics using CT and PET to perform the mediastinal examination. Histology was regarded as the gold standard. Results: PET displayed a high sensitivity (95%) and negative predictive value (NPV) (92%), outperforming CT (89% and 85%, respectively). Percentage agreement with histology was also higher (0.207 and 0.241 for CT and PET, respectively; p < 0.001). Taking an SUVmax value of 0.5 as that which would ensure greatest diagnostic accuracy, S and NPV were 100%, though percentage agreement did not increase (0.189; p < 0.001). PET discriminatory power was not affected by histological tumour subtype. Conclusions: The results of our study indicate that PET might be a useful test for examination of the mediastinum in lung cancer patients. Its high NPV suggests that the absence of mediastinal uptake could be used to proceed to surgical treatment without the need for further tests or examinations. Nevertheless, studies directly aimed to answer this specific question are needed.

Advantages and limitations of 18-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography in the diagnosis of infective endocarditis.

INTRODUCTION: The early diagnosis of infective endocarditis (IE) is a medical challenge and a multidisciplinary approach is essential to improve its frequently fatal prognosis. Our goal was to evaluate the usefulness of [18F]2-fluoro-2-deoxy-d-glucose positron emission tomography (18F-FDG PET) in the diagnosis of this disease. MATERIALS AND METHODS: We prospectively assessed 43 patients (five female and 38 male) with clinical suspicion of IE between 2014 and 2017. All patients underwent transesophageal echocardiography (TEE) and an 18F-FDG PET scan, and the results were compared. A positive PET finding was defined as increased FDG uptake on cardiac valves or intracardiac devices. RESULTS: Out of 43 patients with suspected IE, the diagnosis was confirmed in 30 cases (79.7%). 18F-FDG PET was positive in 24 patients, with 19 showing FDG uptake on cardiac valves (two native and 17 prosthetic) and five on cardiac devices, being concordant with echocardiographic findings in 11 cases. 18F-FDG PET sensitivity was 80%, specificity 92%, positive predictive value (PPV) 96% and negative predictive value (NPV) 66%. Echocardiography presented sensitivity, specificity, PPV and NPV of 36%, 84%, 84% and 36%, respectively. CONCLUSIONS: 18F-FDG PET proved to be a sensitive technique with a high diagnostic value in patients with prosthetic valves and intracardiac devices and suspected IE. Its utility decreased dramatically in patients with suspected IE on native valves, in which TEE presented higher sensitivity and thus better diagnostic value.

Spontaneous bilateral haemothorax as presentation of primary pleural epithelioid haemangioendothelioma.

Pleural epithelioid haemangioendothelioma (EHE) is a rare tumour that originates in the vascular endothelium with an intermediate degree of malignancy between haemangioma and angiosarcoma. Smoking and asbestos exposure are unproven risk factors and diagnosis is usually confirmed by thoracoscopy, since pleural fluid (PF) cytology is often not conclusive. Immunohistochemistry can also help to confirm the diagnosis. We report an 85-year-old patient with bilateral pleural EHE diagnosed by thoracoscopy, who debuted with a spontaneous bilateral haemothorax, the second described so far, and we conducted a thorough review of the literature to describe the clinical, radiological and prognostic features, as well as the PF, of this rare tumour.

Rapid growth of left atrial myxoma after radiofrequency ablation.

Atrial myxoma is the most common benign tumor of the heart, but its appearance after radiofrequency ablation is very rare. We report a case in which an asymptomatic, rapidly growing cardiac myxoma arose in the left atrium after radiofrequency ablation. Two months after the procedure, cardiovascular magnetic resonance, performed to evaluate the right ventricular anatomy, revealed a 10 × 10-mm mass (assumed to be a thrombus) attached to the patient's left atrial septum. Three months later, transthoracic echocardiography revealed a larger mass, and the patient was diagnosed with myxoma. Two days later, a 20 × 20-mm myxoma weighing 37 g was excised. To our knowledge, the appearance of an atrial myxoma after radiofrequency ablation has been reported only once before. Whether tumor development is related to such ablation or is merely a coincidence is uncertain, but myxomas have developed after other instances of cardiac trauma.

Caseous calcification of the mitral annulus: a rare cause of intracardiac mass.

Caseous calcification of the mitral annulus is a rare form of periannular calcification with a mass-like appearance, that has to be in the differential of the cardiologist and radiologist. It classically looks like a round or semilunar hyperdense mass with an even denser peripheral rim, located in the posterior mitral annulus and having in general no clinical significance.

Internal mammary artery dilatation in a patient with aortic coarctation, aortic stenosis, and coronary disease. Case report.

The ideal surgical approach is unclear in adult patients with coarctation of the aorta that is associated with other cardiovascular pathologies that require intervention. Standard median sternotomy allows simultaneous, coronary revascularization surgery, valve replacement and repair of aortic coarctation. However the collateral circulation and the anatomy of the mammary arteries must be determined, to avoid possible complications. We report a case of a 69 year-old man with aortic coarctation, aortic stenosis, coronary artery disease and internal mammary artery dilatation who underwent concomitant surgical procedures through a median sternotomy.

Pulmonary embolism due to biological glue after repair of type A aortic dissection.

Biological glue is increasingly used in cardiac surgery. We report a case of type A aortic dissection repair that was complicated by subsequent pulmonary embolism due to BioGlue(®) (Cryolife Inc, Hennesaw, GA, USA). To our knowledge this is the first report of a case with this complication.