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Diagnostischer Stellenwert der quantitativen myokardialen Perfusionsanalyse für die Detektion der koronaren Herzkrankheit mittels kardialer Magnetresonanztomographie
Get PDFDie kardiale Magnetresonanztomographie (CMR) hat in den letzten Jahrzehnten eine fortlaufende technologische Entwicklung erfahren und stellt heute eine vielseitige diagnostische Methode in der klinischen Routine dar. Die Stress-CMR erlaubt die Detektion einer hämodynamisch relevanten Koronarstenose auf Basis einer pharmakologisch induzierten Vasodilatation. In den vergangenen Jahren wurde zusätzlich zur bisherigen visuellen Beurteilung der Stress-CMR eine voll-automatisierte Quantifizierung des myokardialen Blutflusses (MBF) und der myokardialen Perfusionsreserve (MPR) entwickelt. Hinsichtlich des diagnostischen Stellenwerts dieser quantitativen Perfusionsanalyse existieren bisher kaum Daten, insbesondere bei Patienten mit chronischen Koronarverschlüssen (CTO), welches die schwerste Form der koronaren Herzkrankheit (KHK) darstellt. Das Ziel dieser Studie war die Untersuchung des diagnostischen Werts der automatisierten SCMR-Quantifizierung bei Patienten mit unterschiedlichem Schweregrad einer KHK. In diese Studie wurden 130 Patienten (Alter 66,7 (59,7-75,2) Jahre, 79,2% Männer) eingeschlossen. Die Patienten wurden in drei Gruppen gemäß des Schweregrads der KHK aufgeteilt (nicht-obstruktive KHK [NOCAD] 70%, N=37; CTO, N=36). Die Stress-MBF (SMBF) und myokardiale Perfusionsreserve (MPR) waren signifikant niedriger bei Patienten mit einer CTO im Vergleich zu Patienten mit NOCAD bzw. hochgradiger Stenose. Ein segmentaler SMBF-Wert <1,09 ml/g/min erlaubt eine Differenzierung zwischen CTO und hochgradiger Stenose mit guter Genauigkeit (AUC 0,794 (0,691-0,896)). Die Kombination der visuellen und quantitativen Perfusionsanalyse zeigte die höchste Sensitivität bezüglich der Identifizierung einer zusätzlichen hochgradigen Stenose bei Patienten mit einer CTO (82,6%).
Die Einführung der automatisierten quantitativen Perfusionsanalyse für die SCMR-Befundung hat somit das Potenzial, die nicht-invasive Charakterisierung von Patienten mit (vermuteter) KHK zu verbessern, indem es Aussagen hinsichtlich des Schweregrads der KHK und des Ausmaßes des tatsächlichen Ischämieareals ermöglicht, was durch die bisherige rein visuelle Beurteilung nicht mit vergleichbarer Genauigkeit möglich war. Diese neuen Möglichkeiten der nicht-invasiven Diagnostik können künftig einen Beitrag zu einer zielgerichteten und individualisierten Diagnostik und Behandlung von KHK-Patienten leisten
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Diagnostic value of quantitative myocardial perfusion analysis for the detection of coronary artery disease using cardiac magnetic resonance imaging
No full textCardiac Magnetic Resonance Imaging (CMR) has undergone continuous technological development over the past decades and today represents a versatile diagnostic modality in clinical routine. Stress CMR allows for the detection of hemodynamically relevant coronary stenosis based on pharmacologically induced vasodilation. In recent years, in addition to the conventional visual assessment of stress CMR (SCMR), a fully automated quantification of myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) has been developed. However, data regarding the diagnostic value of this quantitative perfusion analysis remain limited—particularly in patients with chronic total occlusions (CTO), which represent the most severe form of coronary artery disease (CAD). The aim of this study was to evaluate the diagnostic value of SCMR quantification in patients with varying degrees of CAD severity. A total of 130 patients (age 66.7 [59.7–75.2] years, 79.2% male) were included in the study. Patients were divided into three groups according to CAD severity: non-obstructive CAD (NOCAD) (70%, N=37), and CTO (N=36). The stress MBF (SMBF) and MPR were significantly lower in patients with CTO compared to those with NOCAD or severe stenosis. A segmental SMBF value 70%, N=37) και ΧΟΑ (N=36). Η στρες μυοκαρδιακή αιματική ροή (SMBF) και η μυοκαρδιακή εφεδρεία (MPR) ήταν σημαντικά χαμηλότερες σε ασθενείς με ΧΟΑ σε σύγκριση με εκείνους με ΜΑΣΝ ή σοβαρή στένωση. Μια τμηματική τιμή SMBF <1,09 ml/g/min επέτρεψε τη διάκριση μεταξύ ΧΟΑ και σοβαρής στένωσης με καλή ακρίβεια (AUC 0,794 [0,691–0,896]). Ο συνδυασμός οπτικής αξιολόγησης και ποσοτικής ανάλυσης αιμάτωσης παρουσίασε τη μεγαλύτερη ευαισθησία (82,6%) για την αναγνώριση επιπρόσθετης σοβαρής στένωσης σε ασθενείς με ΧΟΑ. Έτσι, η ενσωμάτωση της αυτοματοποιημένης ποσοτικής ανάλυσης αιμάτωσης στη στρες μαγνητική τομογραφία καρδιάς έχει τη δυνατότητα να βελτιώσει τον μη επεμβατικό χαρακτηρισμό των ασθενών με (υποψία) στεφανιαίας νόσου. Επιτρέπει πιο ακριβή εκτίμηση τόσο της βαρύτητας της νόσου όσο και της έκτασης της πραγματικής περιοχής ισχαιμίας, κάτι που δεν ήταν εφικτό με τη χρήση αποκλειστικά της οπτικής αξιολόγησης. Αυτή η νέα δυνατότητα στον τομέα της μη επεμβατικής απεικονιστικής διαγνωστικής ενδέχεται στο μέλλον να συμβάλλει σε πιο στοχευμένη και εξατομικευμένη διάγνωση και θεραπεία των ασθενών με στεφανιαία νόσο
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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