1,720,957 research outputs found
Learning curve in multidetector CT coronary angiography (MDCT-CA)
No full textPURPOSE:
Coronary angiography using multidetector computed tomography (MDCT-CA) is a recent technique for the nonivasive study of coronary arteries. This study assessed the diagnostic accuracy of coronary artery stenosis evaluation obtained by three readers at different levels of training or at different points of the learning curve proposed by the international guidelines.
MATERIALS AND METHODS:
Three radiologists in training with different levels of experience in MDCT-CA scored 50 cases at various time points of the learning curve: baseline, 4 weeks, 8 weeks and 6 months. The trainee radiologists evaluated the degree of stenosis on each coronary segment, and overall accuracy was calculated on a per-segment, pervessel and per-patient basis.
RESULTS:
All readers improved analysis accuracy per segment (range, 73-90%); sensitivity reached 45% per segment, 84% per vessel and 93% per patient; specificity was 99% per segment and vessel and 98% per patient. Positive and negative predictive values increased to 94% and 92%, respectively.
CONCLUSIONS:
Although all readers improved in diagnostic performance with growing experience with MDCT-CA, a longer training period may be necessary to achieve adequate levels of expertise in MDCT-CA to be able to perform as independent readers
Normal anatomy and variants of the venous cardiac system in MDCT coronary angiography
No full textThree separate venous systems drain the blood returning from the heart walls. These veins are characterised by remarkable variability in terms of frequency, size and course. The knowledge of cardiac venous anatomy is of primary importance during interventional cardiac procedures that require catheterisation of cardiac veins. Some anatomical variants may hinder or contraindicate access to target veins. Coronary angiography (CA) with multidetector computed tomography (MDCT-CA) and multiplanar reformations (MPR), maximum intensity projection (MIP) and 3D reconstructions provides noninvasive visualisation of normal cardiac veins and anatomical variants. The purpose of this pictorial review is to describe by MDCT-CA the anatomy and main variants of the cardiac venous system
Avvio di un sistema gestionale per la performance dei medici presso il pronto soccorso di un'Azienda Ospedaliera del Veneto
No full textINTRODUZIONE: Negli ultimi anni in Italia si riscontra un costante
aumento da parte della popolazione generale a ricorrere alle strutture di emergenza-urgenza ospedaliera, con importanti ripercussioni sul versante organizzativo e gestionale.
OBIETTIVO: Valutare mediante indicatori di performance quali-quantitativa l’attività del Pronto Soccorso (PS) dell’Ospedale Civile Maggiore di Verona.
MATERIALE E METODI: È stato sviluppato nell’ambito del sistema
informativo del PS un sistema gestionale per l’analisi della performance dei medici afferenti all’Unità Operativa. Sono stati considerati gli accessi avvenuti dal 1° gennaio al 31 luglio 2007.
RISULTATI: Sono stati registrati 48.889 accessi. I tempi di attesa sono risultati proporzionali alla priorità assegnata al triage: in media 4,4 minuti per i codici rossi (dovuti ai tempi tecnici di registrazione della scheda), 9 per i gialli, 31,6 per i verdi e 30,3 per i bianchi. 5.848 accessi (12,0%) sono esitati in ricovero di cui oltre il 30% (1.970) in un reparto geriatrico. In media sono state erogate 2,9 prestazioni, 8 esami di laboratorio e 1,5 esami strumentali per paziente. Quest'ultimo dato si differenzia per alcuni esami strumentali a seconda del medico prescrittore: -Rx addome: max=1/5 pz; min=1/333 pazienti - Ecodoppler: max=1/20 pazienti; min=0 -Ecoaddome: max=1/17 pazienti;
min=1/1000 pazienti -Rx torace: max=1/3 pazienti; min=1/200
pazienti. La variabilità di accesso alla diagnostica per immagini registrata tra professionisti può essere solo parzialmente giustificata dalla variabilità clinica dei casi, trovando spiegazione anche nella variabilità dei percorsi diagnostici seguiti dai singoli medici.
CONCLUSIONI: I risultati sembrano indicare che il sistema di valutazione gestionale implementato possa fornire una prima base di dati per analizzare l’appropriatezza clinico-organizzativa dei percorsi assistenziali seguiti nella gestione degli accessi al PS. La variabilità nel ricorso alla diagnostica per immagini sembra indicare la necessità di adottare protocolli condivisi tra i diversi professionisti e di avviare un sistema di monitoraggio del loro utilizzo
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
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