1,721,007 research outputs found
Role of multimodality imaging in evaluation of cardiovascular involvement in COVID-19
No full textThe management of patients infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may be difficult due to the need for dedicated in-hospital pathways, protective measures for healthcare professionals and isolated beds of intensive care, particularly in areas overwhelmed by wide viral spread. Although pneumonia is the most common clinical manifestation in coronavirus disease 2019 (COVID-19), a variety of cardiovascular complications have been reported. An integrated diagnostic algorithm in SARS-CoV-2-infected patients with suspected cardiac involvement (laboratory findings of myocardial injury and electrocardiographic changes) may help to avoid unnecessary examinations and minimize the risk of operator infection. Due to its mobility and bedside feasibility, echocardiography is the first-line imaging technique in this clinical setting. It quickly provides information on ventricular functions, pulmonary hypertension, valve disease and pericardial effusion. In case of ST-segment elevation (STE), urgent coronary angiography should be performed. Cardiac ultrasound helps distinguish between ischemic and non-ischemic myocardial disease and may detect pericardial disease. Transmural ischemic electrocardiographic changes, with or without early elevated troponin levels or echocardiographic wall motion abnormalities, will determine the need for early invasive coronary angiography. Computed tomography (CT) through its multiple applications (chest CT; CT pulmonary angiography and coronary CT angiography; late iodine enhancement CT) and cardiac magnetic resonance might be helpful in reinforcing or redirecting diagnostic hypothesis emerged by other clinical, electrocardiographic and echocardiographic findings. The current pandemic makes it challenging to perform serial invasive and non-invasive diagnostic testing in COVID-19 patients and high serum troponin level. Nevertheless, thoughtful and systematic use of an appropriate multimodality imaging strategy is clinically relevant to detect cardiac injury and distinguish myocardial infarction from, myocarditis, takotsubo syndrome and pulmonary embolism
Spontane Koronararteriendissektion
No full textSpontaneous coronary artery dissection Abstract. Spontaneous coronary artery dissection (SCAD) is an increasingly recognized etiology of acute coronary syndrome (ACS) and an important cause of myocardial infarction in women. First described in 1931, SCAD is defined as a spontaneous tear in a coronary artery that is not associated with atherosclerosis, trauma or medical intervention. SCAD predominantly affects younger women, who often lack atherosclerotic risk factors. Some risk factors that have been identified include female sex, pregnancy, severe emotional or physical stress, underlying blood vessel diseases such as fibromuscular dysplasia, and connective tissue diseases such as Ehlers-Danlos syndrome or Marfan syndrome. Previously believed to be rare, a chiefly fatal condition, recent epidemiological data suggests SCAD is accountable for up to 4 % of all ACS cases and up to 35 % of ACS cases in women < 50 years of age. There is a lack of awareness of SCAD among physicians, which probably results in underreporting and underdiagnosing of this disorder. The clinical presentation of SCAD is often similar to that of ACS making differentiation at first presentation difficult. Cardiac enzymes are elevated like in ACS and there are no biomarkers that are specific for the diagnosis of SCAD. Coronary angiography is the gold standard method to distinguish both entities, however correct diagnosis by cath is challenging and SCAD can be truly missed and misdiagnosed as classic ACS. Still there are no randomized controlled trials about the optimal treatment of these patients. But it is suggested that management should be different to atherosclerotic myocardial infarction. Conservative medical treatment is favored in the majority of cases, with percutaneous coronary intervention (PCI) being reserved for high risk patients due to poor interventional outcomes and higher failure rates. However, there is still a lack of data on this poorly understood condition and the optimal management has yet to be determined
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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