1,721,102 research outputs found
Assessment of Systolic Wall Thickening Using Technetium-99m Methoxyisobutylisonitrile in Patients with Coronary Artery Disease: Relation to Thallium-201 Scintigraphy with Reinjection
No full textThe results of resting planar ECG-gated technetium-
99m methoxyisobutylisonitrile (99mTc-MIBI) imaging
were compared with those of thallium-201 (T1) reinjection
after exercise-redistribution scintigraphy in 20
patients (19 men, 1 woman, mean age 53_10 years) with
angiographically proven coronary artery disease. Eight
normal subjects (seven men, one woman, mean age 50___8
years) constituted the control group. In these subjects,
only resting 99mTc-MIBI imaging was performed. The
standardized percent count increase from end-diastole to
end-systole was calculated as an index of wall thickening
in 13 segments for each study. Regional wall thickening
index (WTI) and 99mTc-MIBI uptake were significantly
different (P<0.05) among segments classified as
normal, reversible defects, irreversible defects with increased
tracer uptake after re-injection (Re+) or irreversible
defects with unchanged tracer uptake after re-injection
(Re-) on T1 imaging. Furthermore, WTI and 99mTCMIBI
uptake were significantly higher (P<0.05) in Resegments
with moderate reduction of T1 uptake (>_50%
of peak activity) than in Re- segments with severe reduction
of T1 uptake (<50% of peak activity). A significant
relationship between WTI and the results of T1 scintigraphy
was observed (rho=0.71, P<0.0001). The percentage
of Re- segments with severe reduction of WTI
was significantly higher compared to Re+ segments
(64% vs 3%, P<0.01). Furthermore, compared with
moderate Re- segments, a significantly higher percentage
of severe Re- segments showed a severe reduction
of WTI (86% vs 48%, P<0.01). Our data document a
close relationship between 99mTc-MIBI regional wall
thickening, myocardial perfusion and T1 uptake after reinjection.
The results of this study suggest that regional
Correspondence to: A. Cuocolo, Via Posillipo 66, 1-80123 Napoli,
Italy
WTI decreased significantly as myocardial perfusion decreased.
In addition, regional wall thickening was preserved
in segments with exercise-induced ischaemia and
enhanced T1 uptake after re-injection
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
Nuclear medicine procedures in cardiovascular diseases. An evidence based approach
No full textThe aim of evidence-based medicine is to integrate individual clinical expertise with the best available external clinical evidence from systematic research. The aim of this article is to introduce the concept of evidence based medicine and to review the evidence for applying cardiovascular nuclear medicine in various clinical settings. A systematic review is defined as a scientific technique to identify and summarize evidence on effectiveness of interventions and to allow the consistency of research. Different clinical applications of nuclear medicine procedures in cardiology have been reviewed. Radionuclide imaging techniques appear to be appropriate in risk assessment, prognosis and evaluation of therapy in patients after acute myocardial infarction. In patients with unstable angina, radionuclide testing is indicated in the identification of ischemia within the distribution of the "culprit" lesion or in remote areas. Exercise and pharmacological cardiac perfusion imaging are appropriate and useful in the diagnosis and prognosis of chronic coronary artery disease. Nuclear medicine procedures are also useful in the assessment of myocardial viability in patients with left ventricular dysfunction, in the assessment of interventions for the evaluation of patients after percutaneous transluminal coronary angioplasty and coronary artery bypass grafting. There has been rapid evolution in radionuclide imaging technologies and both the number and the complexity of choices for the clinician have increased. Further progress in technology and clinical applications of nuclear cardiology may be expected. The development of new instrumentation and of new agents will allow consistent progress and improve the state-of-art of nuclear cardiology. Thus, guidelines for the use of cardiac radionuclide imaging have been difficult to develop and apply. An evidence-based approach may be useful for the best use of nuclear medicine procedures in cardiovascular diseases
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
Comparison of left ventricular function by gated myocardial perfusion scintigraphy with image inversion technique with equilibrium radionuclide angiography (RNG)
No full text
Detection of Myocardial Viability: Comparison Between Thallium-201 Reinjection and 99m-Tc-MIBI
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