1,720,964 research outputs found
Dual energy imaging and intracycle motion correction for CT coronary angiography in patients with intermediate to high likelihood of coronary artery disease
Full text linkWe explored whether intracycle motion correction algorithms (MCAs) might be applicable to dual energy computed tomography coronary angiography in patients with intermediate to high likelihood of coronary artery disease. MCA reconstructions were associated with higher interpretability rates (96.7% vs 87.9%, P < .001), image quality scores (4.12±0.9 vs. 3.76±1.0; P < .0001), and diagnostic performance [area under the curve of 0.95 (95% confidence interval [CI] 0.92-0.97) vs 0.89 (95% CI 0.86-0.92); P < .0001] compared to conventional reconstructions. In conclusion, application of intracycle MCA reconstructions to dual energy computed tomography acquisitions was feasible and resulted in significantly higher image quality scores, interpretability, and diagnostic performance.Fil: Carrascosa, Patricia. Diagnóstico Maipú; ArgentinaFil: Deviggiano, Alejandro. Diagnóstico Maipú; ArgentinaFil: Leipsic, Jonathon A.. St. Paul's Hospital; CanadáFil: Capunay, Carlos. Diagnóstico Maipú; ArgentinaFil: De Zan, Macarena C.. Diagnóstico Maipú; ArgentinaFil: Goldsmit, Alejandro. Sanatorio Güemes; ArgentinaFil: Rodriguez Granillo, Gaston Alfredo. Diagnóstico Maipú; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas; Argentin
Effect of Intracycle Motion Correction Algorithm on Image Quality and Diagnostic Performance of Computed Tomography Coronary Angiography in Patients with Suspected Coronary Artery Disease
Full text linkRationale and objectives: We sought to explore the impact of intracycle motion correction algorithms (MCA) in the interpretability and diagnostic accuracy of computed tomography coronary angiography (CTCA) performed in patients suspected of coronary artery disease (CAD) referred to invasive coronary angiography. Materials and Methods: Patients with suspected CAD referred to invasive coronary angiography previously underwent CTCA. Patients under rate-control medications were advised to withhold for the previous 24hours. The primary end point of the study was to evaluate image interpretability and diagnostic performance of MCA compared to conventional reconstructions in patients referred to invasive angiography because of suspected CAD. Results: Thirty-five patients were prospectively included in the study protocol. The mean age was 61.4±9.4years. Twenty-seven (77%) patients were men. A total of 533 coronary segments were evaluated using conventional and MCA reconstructions. MCA reconstructions were associated to higher interpretability rates (525 of 533, 98.5% vs. 515 of 533, 96.6 %; P<.001) and image quality scores (3.88±0.54 vs. 3.78±0.76; P<.0001) compared to conventional reconstructions. Although only mild, a significant difference was observed regarding the diagnostic performance between reconstruction modes, with an area under the curve of 0.90 (0.87-0.92) versus 0.89 (0.86-0.92), respectively, for MCA and conventional reconstructions (. P=.0447). Conclusions: In this pilot investigation, MCA reconstructions performed in patients with suspected CAD were associated to higher interpretability rates and image quality scores compared to conventional reconstructions, although only mild differences were observed regarding the diagnostic performance between reconstruction modes.Fil: Carrascosa, Patricia. Sanatorio Güemes; Argentina. Diagnóstico Maipú; ArgentinaFil: Deviggiano, Alejandro. Sanatorio Güemes; Argentina. Diagnóstico Maipú; ArgentinaFil: Capunay, Carlos. Sanatorio Güemes; Argentina. Diagnóstico Maipú; ArgentinaFil: De Zan, Macarena C.. Sanatorio Güemes; Argentina. Diagnóstico Maipú; ArgentinaFil: Goldsmit, Alejandro. Sanatorio Güemes; Argentina. Diagnóstico Maipú; ArgentinaFil: Rodriguez Granillo, Gaston Alfredo. Diagnóstico Maipú; Argentina. Sanatorio Güemes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
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
Invasive coronary angiography findings across the CAD-RADS classification spectrum
No full textThe recently introduced coronary artery disease reporting and data system (CAD-RADS) evaluated by computed tomography and based on stenosis severity, might not adequately reflect the complexity of CAD. We explored the relationship between CAD-RADS and the spatial distribution, burden, and complexity of lesions by invasive coronary angiography (ICA). Stable patients who underwent coronary computed tomography angiography (CCTA) and ICA comprised the study population. Patients were classified according to the CAD-RADS: 0, No plaque; 1, 1–24% stenosis; 2, 25–49%; 3, 50–69%; 4A, 70–99%; 4B, left main stenosis or 3-vessel obstructive disease; and 5, total occlusion. Based on ICA findings, we calculated the SYNTAX score and the CAD extension index. Ninety-one patients were included, with a mean age of 61.4 ± 10.5 years (74% male). We found significant relationships between CAD-RADS and both the SYNTAX score (p 5. Of the 30 patients with CAD-RADS 5, 9 (30%) affected distal segments or secondary branches, and 9 (30%) had concomitant severe non-extensive disease at ICA. Regarding the spatial distribution of the non-occluded most severe lesions, 27 (44%) comprised distal segments or secondary branches. In the present study including a high-risk population, we identified diverse coronary anatomy complexity scenarios and relevant differences in spatial distribution sharing the same CAD-RADS classification.Fil: Rodriguez Granillo, Gaston Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas; Argentina. Diagnóstico Maipú; ArgentinaFil: Carrascosa, Patricia. Diagnóstico Maipú; ArgentinaFil: Goldsmit, Alejandro. Sanatorio Guemes Sociedad Anonima.; ArgentinaFil: Arbab Zadeh, Armin. University Johns Hopkins; Estados Unido
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
Pericardial fat volume is related to atherosclerotic plaque burden rather than to lesion severity
Full text linkAims: We sought to explore the relationship between pericardial fat volume (PFV) and both coronary atherosclerosis (CA) extent and severity using coronary artery calcium score (CAC), computed tomography coronary angiography (CTCA), and invasive coronary angiography in patients at high to intermediate likelihood of coronary artery disease (CAD). Methods and results: Patients clinically referred to invasive angiography who underwent CTCA and CAC within 1 month before the procedure comprised the study population. PFV, CAC, atherosclerotic burden indexes [segment involvement score (SIS); segment stenosis score; three-vessel plaque; and any left main plaque], and the invasive angiography-derived CAD index were evaluated independently. A total of 75 patients were included in the study. PFV did not differ between patients with or without obstructive (stenosis .70%) CAD defined by invasive angiography (86.4±31.7 vs. 77.1±42.8 cm3, P = 0.34), although patients with obstructive CAD had significantly higher CAC scores [636.0 (IQR 229.5-1101.0) vs. 206.0 (IQR 0.0-675), P<0.0001] than patients without obstructive CAD. Patients with extensive CA (SIS . 5) had significantly larger PFV (89.9±33.9 vs. 58.7±33.2 cm3, P = 0.003) than patients with non-extensive CA. Significant correlations were found between PFV and CAC (r = 0.49, P<0.0001), and SIS (r = 0.46, P<0.0001), whereas very weak correlations were observed between PFV and the CAD index (r = 0.27, P = 0.02), and between PFV and the body mass index (r = 0.33, P = 0.004). Conclusion: The main finding of the present study was the identification of PFV as more closely related to atherosclerotic plaque burden rather than to lesion severity in patients referred to invasive coronary angiography.Fil: Rodriguez Granillo, Gaston Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas; Argentina. Diagnóstico Maipú; ArgentinaFil: Carrascosa, Patricia. Diagnóstico Maipú; ArgentinaFil: Deviggiano, Alejandro. Diagnóstico Maipú; ArgentinaFil: Capunay, Carlos. Diagnóstico Maipú; ArgentinaFil: De Zan, Macarena C.. Diagnóstico Maipú; ArgentinaFil: Goldsmit, Alejandro. Sanatorio Güemes; ArgentinaFil: Campisi, Roxana. Diagnóstico Maipú; Argentin
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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