1,720,973 research outputs found
Optic nerve sheath diameter (ONSD) in sovratentorial brain tumor surgery: an option for non invasive raised ICP detection and management. Preliminary results and feasibility assessment (06AP04-9)
No full textBackground and Goal of Study: Increase in optic nerve sheath diameter (ONSD) in transorbital sonography has been proven to be able to non-invasively detect elevated intracranial pressure in different clinical scenarios. The aim of this study is to assess the feasibility of ONSD sonography method detecting changes in intracranial pressure in patients with sovratentorial brain tumors.
Materials and Methods: After a learning curve of 25 cases, for two intensivists, high-frequency linear probes 7 Mhz are used to measure ONSD (ophthalmic artery - optic nerve cross point) in a patients population with sovratentorial brain solid tumors scheduled to elective neurosurgery.
A convenience small sample of patients’ cohort with sovratentorial brain tumors scheduled to elective neurosurgery was analyzed.
ONSD was measured, also, in preoperative RMN and/or CT scan and compared with postoperative CT scan in another small cohort of patients.
Results and Discussion: A total of 25 encounters were completed. ONSD was enlarged in 94.3% of patients bilaterally (cut off > 5.5 mm). The mean ultrasound ONSD before surgery was 6,64 +/- 0,33 mm preoperatively and 5,31 +/- 0,10 mm postoperatively. Mean ONSD on CT/MRI scan was respectively 5,62 +/- 0,51 mm preoperatively and 5,42 +/- 0,46 mm postoperatively. We also found a good correlation between the side of lesion and rasied ONSD.
Conclusion(s): ONSD ultrasound measurement in sovratentorial tumors patient population could be an optional non invasive method, beside CT or MRI to detect changes in intracranial pressure even if the paucity of the sample can’t allow us to make a precise assessment.
References:
Moretti R, Pizzi B Ultrasonography of the optic nerve in neurocritically ill patients, Acta Anaesthesiol Scand 2011; 55: 644-652.
Bekerman I, Sigal T, Kimiagar I, Almer ZE, Vaiman M., Diagnostic value of the optic nerve sheath diameter in pseudotumor cerebri. J Clin Neurosci. 2016 Aug;30:106-9.
Frederick A. Zeiler, Markus T.Ziesmann, Patrick Goeres, Bertram Unger, Jason Park1, Dimitrios Karakitsos, Michael Blaivas, Ashley Vergis and Lawrence M. Gillman - A unique method for estimating the reliability learning curve of optic nerve sheath diameter ultrasound measurement - Crit Ultrasound J (2016) 8:
Non-selective attention and nitric oxide in putative animal models of Attention-Deficit Hyperactivity Disorder
No full textA Proposal for a New Protocol for Sonographic Assessment of the Optic Nerve Sheath Diameter: The CLOSED Protocol
No full textMeasuring and monitoring of intracranial pressure is considered standard of care in patients with suspected intracranial hypertension. Sonographic assessment of the optic nerve sheath diameter (ONSD) has been promising and potentially useful for noninvasive intracranial hypertension screening. ONSD measurements are easy to perform, repeatable at bedside, fast, low cost, and radiation-free. However, they are still burdened by inter-rater variability, lack of ultrasound (US) setting standardization (e.g., US frequency, focus depth, etc.), and possible artifacts. To overcome this problem, we propose the CLOSED protocol associated with equipment specifications, as a guide to minimize the occurrence of such artifacts enabling a more reliable and accurate measurement. We suggest that color Doppler could be used as a new standard evaluation for the ONSD
A Proposal for a New Protocol for Sonographic Assessment of the Optic Nerve Sheath Diameter: The CLOSED Protocol
No full textNon-selective attention in a rat model of hyperactivity and attention deficit: subchronic methylphenydate and nitric oxide synthesis inhibitor treatment
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
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