We describe the observed and quantitative signal intensity changes in the brain on baseline precontrast T1-weighted MRI data of a pediatric patient who received 35 MRI examinations with gadolinium-based contrast agent (GBCA) between the ages of 8 and 20 years. The contrast agent this patient received belongs to a class of agents with linear molecular structures, which has been recently investigated in studies of gadolinium deposition in the brains of adult patients. Visual changes in signal intensity were assessed by 3 pediatric neuroradiologists, and progressive increases were the most evident in the dentate nuclei, the globus pallidus, and the thalamus. Quantitative measurements as determined from signal intensity ratios confirmed visual findings. The pattern of regional brain hyperintensity observed in this pediatric patient is consistent with findings from adult studies.Recent reports have demonstrated qualitative and quantitative changes in the brains of adult patients, suggesting that tissue MRI gadolinium contrast deposition was the cause.

Objectives Investigate the feasibility of saliva sampling as a noninvasive and safer tool to detect SARS-CoV-2 and to compare its reproducibility and sensitivity with nasopharyngeal swab samples (NPS). The use of sample pools was also investigated. Methods 2107 paired samples were collected from asymptomatic health care and office workers in Mexico City. Sixty of these samples were also analyzed in two other independent laboratories for concordance analysis. Sample processing and analysis of virus genetic material were performed according to standard protocols described elsewhere. Pooling analysis was performed by analyzing the saliva pool and the individual pool components. Results The concordance between NPS and saliva results was 95.2% (Kappa: 0.727, p = 0.0001) and 97.9% without considering inconclusive results (Kappa: 0.852, p = 0.0001). Saliva had a lower number of inconclusive results than NPS (0.9% vs 1.9%). Furthermore, saliva shows a significantly higher concentration of both total RNA and viral copies than NPS. Comparison of our results with those of the other two laboratories shows 100% and 97% concordance. Saliva samples are stable without the use of any preservative, a positive SARS-CoV-2 sample can be detected 5, 10, and 15 days after collection when the sample is stored at 4 °C. Conclusions Our results indicate that saliva is as effective as NPS for the identification of SARS-CoV-2-infected asymptomatic patients, sample pooling facilitates the analysis of a larger number of samples with the benefit of cost reduction.

Valve replacement is the most common surgical treatment in patients with advanced valvular heart disease. Mechanical and bio-prostheses have been the traditional heart valve replacements in these patients. However, currently the heart valves for replacement therapy are imperfect and subject patients to one or more ongoing risks, including thrombosis, limited durability, and need for re-operations due to the lack of growth in pediatric populations. Furthermore, they require an open heart surgery, which is risky for elderly and young children who are too weak or ill to undergo major surgery. This article reviews the current state of the art of heart valve replacements in light of their potential clinical applications. In recent years polymeric materials have been widely studied as potential prosthetic heart valve material being designed to overcome the clinical problems associated with both mechanical and bio-prosthetic valves. The review also addresses the advances in polymer materials, tissue engineering approaches, and the development of percutaneous valve replacement technology and discusses the future prospects in these fields.

BACKGROUND AND PURPOSE:A challenge with the T1-weighted postcontrast Cartesian spin-echo and turbo spin-echo brain MR imaging is the presence of flow artifacts. Our aim was to develop a rapid 2D spiral spin-echo sequence for T1-weighted MR imaging with minimal flow artifacts and to compare it with a conventional Cartesian 2D turbo spin-echo sequence.

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Pregnancy results in substantial hemodynamic and prothrombotic changes that form the foundation for downstream vascular complications, both during pregnancy and in the postpartum period. In addition, several important risk factors, including older patient age, diabetes, and smoking, can increase the risk for vascular-related pregnancy complications. Because radiologists often play an important role in evaluation of the pregnant patient, understanding the pathophysiology of vascular-related complications in pregnancy and their imaging appearances is essential for diagnostic accuracy. The authors review relevant normal physiologic changes of pregnancy, pathophysiologic changes, and imaging features of vascular conditions that can manifest in conjunction with pregnancy. Particular attention is given to pertinent imaging information that radiologists should provide to referring clinicians to optimally affect the management of pregnant patients as well as women in the peripartum and postpartum stages. Among the complications discussed are preeclampsia; hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome; spontaneous coronary artery dissection; placental abruption; amniotic fluid embolism and acute pulmonary embolism; dural venous sinus thrombosis; ovarian vein thrombophlebitis; vasa previa; uterine arteriovenous malformations; heritable aortopathies; and hereditary hemorrhagic telangiectasia. To help radiologists avoid the use of unnecessary ionizing radiation in pregnancy, imaging examination selection and optimization are also reviewed. Radiologists should be familiar with the physiologic changes of pregnancy, radiation risks during gestation, and pregnancy-related vascular complications to improve imaging examination selection, diagnosis, and clinical management. RSNA, 2017.

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