1,721,000 research outputs found
Assessment of no reflow phenomenon after acute myocardial infarction using harmonic angio and intravenous pump infusion with levovist. comparison with intracoronary contrast injection
No full textMyocardial contrast echocardiography (intracoronary application) has emerged as an accurate method to detect the “no-reflow phenomenon.” To investigate the diagnostic value of harmonic angiography after intravenous infusion of Levovist in assessing “no-reflow,” both intracoronary and intravenous contrast injections were performed in a group of patients with acute myocardial infarction. Seventeen consecutive patients with a successfully reperfused acute myocardial infarction within 6 hours of symptom onset were selected for this study. All patients underwent contrast echocardiography with harmonic angiography with Levovist (400 mg/mL, intravenous pump infusion, trigger intervals 1:4 to 1:8) and sonicated albumin (0.5 to 1 mL, intracoronary bolus) on day 1 after the achievement of a sustained coronary reflow. Myocardial perfusion was qualitatively assessed with a 12-segment model. The endocardial length of the residual contrast defect after reflow was also calculated. Forty-four of 204 segments were not analyzed after intravenous contrast echocardiography and 37 after intracoronary contrast echocardiography because of artifacts. Intracoronary and intravenous injections showed a perfusion defect in 31 (19%) segments, with a concordance of 89% (κ coefficient, 0.72). Concordance in anteroseptal, anterolateral, and inferolateral segments was 95% (κ = 0.92), 88% (κ = 0.66), and 83% (κ = 0.57), respectively. With intracoronary injection used as the reference method, intravenous injection had a sensitivity of 74% and a specificity of 93% for diagnosing contrast defects. The endocardial extent of no-reflow was 18 ± 19 after intravenous and 21 ± 17 after intracoronary contrast echocardiography (P = not significant). Intravenous contrast echocardiography with Levovist reliably identifies the no-reflow phenomenon after successful reperfusion, especially in acute anteroseptal myocardial infarction. (J Am Soc Echocardiogr 2001;14:773-81.
Different patterns of left ventricular dilatation after coronary reperfusion: results from the Acute Myocardial Infarction Contrast Imaging (AMICI) multicenter study. (Abs)
No full textDetection of residual tissue viability within the infarct zone in patients with acute myocardial infarction:ultrasonic integrated backscatter analysis versus dobutamine stress echocardiography
No full textAbstract
OBJECTIVES:
The goals of this study were to analyze temporal changes in cardiac cyclic variation of integrated backscatter (CVIB) in acute myocardial infarction (AMI) and to investigate the predictive value of CVIB normalization compared with that of dobutamine stress echocardiography (DSE) in the assessment of functional recovery after revascularization.
BACKGROUND:
The normal CVIB is blunted by ischemia and recovers early after reperfusion, faster than wall motion improvement. Analysis of CVIB has been widely investigated for its potential to detect viable myocardium in the early stage of infarction. No studies have compared CVIB analysis with other techniques for viability assessment in patients with acute ischemic. Methods and Results: Integrated backscatter images were obtained in 12 patients with AMI on days 1, 3, and 7 after admission and 1 month after revascularization. On day 7, DSE was performed in all patients. On admission, 22 of 144 segments were dyssynergic. On day 1, CVIB was abnormal in all 22 infarcted segments, on day 3, in 16, and on day 7, in only 10 infarcted segments. Eight of 10 segments nonviable by CVIB (CVIB-nonviable) were also nonrespondent by DSE; whereas 12 of 14 segments viable by DSE (DSE-viable) were also CVIB-viable. At follow-up, 10 CVIB-viable segments and 1 CVIB-nonviable segment showed functional recovery; whereas 10 of 14 DSE-viable segments showed functional recovery. Thus the positive predictive value of CVIB and DSE was 83% and 72%, respectively, with a diagnostic agreement between techniques in 77% of segments.
CONCLUSIONS:
Our data suggest that the normalization in CVIB in the first week after AMI accurately predicts residual tissue viability within the infarct zone. We also observed that the initial pattern of cyclic variation may be predictive of functional recovery. Finally, we found a good correlation between the recovery of a normal CVIB in segments that were still dysfunctional and a more validated method to assess tissue viability, such as the dobutamine test
Ecocontrastografia miocardica: cenni storici, aspetti metodologici e applicazioni cliniche
Full text linkImpact of gender on the relation between myocardial viability and contractile recovery of post-ischemic left ventricular dysfunction: results of the AMICI multicenter study
No full text
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
- …
