1,720,966 research outputs found
Contrast-enhanced ultrasound examination of the breast: A literature review
No full textAngiogenesis is the basis for neoplastic growth in human tissues. Nevertheless, neovascularization may be present both in benign and malignant lesions. Although microvascular density assessment is a useful tool for the study of neoplastic vascularization, it cannot be used on a large scale because of the invasiveness of the method. When contrast-enhanced ultrasonography (CEUS) was introduced in clinical practice, the initial results in the field of breast lesions were disappointing because differentiation between benign and malignant masses was not possible. Magnetic resonance imaging (MRI) assessment of the microvascular features was therefore immediately accepted because of the higher diagnostic accuracy. However, in the last decade the sensitivity and specificity of CEUS have greatly improved due to the development of more sophisticated ultrasound (US) equipment, the introduction of second-generation contrast agents and the development of dedicated software able to perform quantitative analysis. This literature review compares the main results reported in the literature regarding the use of CEUS for the characterization of neoplastic lesions of the breast. All the authors agreed that malignant lesions show early wash-in with more intense enhancement and fast wash-out in comparison with benign masses. However, there is still no observer agreement regarding vascularization patterns, and different classifications are proposed. The conclusion of this literature review is therefore that the clinical role of CEUS in the diagnostic process and in follow-up is still to be clearly defined. © Georg Thieme Verlag KG Stuttgart · New York
CEUS in the differentiation between low and high-grade bladder carcinoma
No full textIntroduction: Bladder cancer ranks 4th overall in the number of newly diagnosed cancers and 10th in causes of cancer deaths. More than 90% of all cases of bladder cancer are transitional cell carcinoma (TCC). The goal of this study is to confirm the usefulness of low mechanical index contrast-enhanced ultrasonography (CEUS), also in association with time-intensity curves, in the differentiation between high- and low-grade bladder malignant lesions. Materials and methods: From February 2006 to February 2012 we recruited 144 patients. All patients underwent grayscale ultrasonography (US), color-Doppler ultrasonography (CDUS) and contrast-enhanced ultrasonography (CEUS). Subsequently all patients underwent cystoscopy and TURB. Results: Histological diagnoses were: 88 high-grade carcinomas (61.1%), and 56 low-grade carcinomas (38.9%). Sensitivity and specificity of CDUS were 87.5% (126/144) and 60%, respectively. Sensitivity and specificity of CEUS were 90.9% and 85.7%, respectively. Sensitivity and specificity of TIC were 91.6% (132/144) and 85.7%, respectively. Discussion and conclusions: CEUS is a reliable noninvasive method for differentiating low- and high-grade bladder carcinomas since it provides typical enhancement patterns as well as specific contrast-sonographic perfusion curves. © 2012 Elsevier Srl
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
Contrast-Enhanced Ultrasonographic (CEUS) and elastosonographic features of a case of testicular leydig tumor
No full textDispelling 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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