1,720,972 research outputs found
Unusual diagnostic findings in temporal lobe epilepsy: A combined MRI and 18F-dopa case study
Get PDFTemporal lobe epilepsy is the most common focal epilepsy in adults and often causes pharmacoresistant seizures. Magnetic resonance imaging (MRI) and PET studies have widely demonstrated a number of morphological and molecular abnormalities in epilepsy. However, considering the dopaminergic system, only a bilateral 18F-DOPA uptake reduction within the basal ganglia has been described. We report the unusual finding of increased 18F- DOPA uptake in a patient with focal recurrent seizures and "deja vu" experiences in the setting of cortical swelling detected at MRI exam. The final diagnosis was in in keeping with hippocampal sclerosis, confirmed during follow-up MR exams. In this case 18F-DOPA uptake may represent increased dopamine transport induced by seizures. Nuclear medicine physicians and radiologists should be aware of clinical and electroencephalo- graphic findings when interpreting brain areas of tracer uptake, which are not always related to malignancy
Non invasive determination of IDH mutation status in high-grade gliomas: utility of ADC maps and (18F)-DOPA PET/ TC
No full textAim The brain tumors new classification (2016 WHO) distinguishes diffuse gliomas based on the molecular characteristics of isocitrate dehydrogenase (IDH) in IDH-mutated, IDH-wild type (WT) and not otherwise specified. The evaluation of IDH mutation status has diagnostic, prognostic and therapeutic implications. The aim of this study is to evaluate whether the analysis of ADC maps and (18F-DOPA) can non-invasively predict the IDH mutation status. Conventional MRI and ADC maps of 16 patients (11-M, 5-F) with histological diagnosis of high-grade diffuse glioma GIII, GIV and the evaluation of IDH mutation status (9-MUT, 7-WT), were retrospectively evaluated. Methods All MRI were performed on a 1.5T MR scan (GE-optima 450). In order to place the ROIs on the solid components of the lesion, the ADC maps were elaborated and co-registered with the T2w and c.e.T1w images. The ADC-mean values were calculated, choosing the lowest values for each patient. The same procedure was performed with PET/CT scan using (18F)-DOPA as tracer. We placed (VOIs) in the same area where was applied the ROIs in RM scan in both groups of patients in order to calculate the SUV-mean values between IDH-MUT and IDH-WT. To compare the ADCmean and SUVmean values between IDH-MUT and IDH-WT performing Student's "t" test, considering significant value of p <0.05 in both groups. Results The ADCmean values in IDH-WT patients (0.86x10-3mm2/s ± 0.06)were lower than those of IDH-MUT patients (1.24x10-3mm2 /s ±0.19) with difference between the two groups significant for p<0.01. The value of ADC ≥ 1.01 x10-3mm2/s can be considered asa "cut-off" to differentiate them mutation status. The ratio between tumor uptake to background in PET/CT scan in IDH-WT group was (2.59x10-3mm2/s ± 0,448), higher than in IDH-MUT group (1.9x10-3mm2/s ± 0,533), with a significative p<0,05. Conclusion In the standard routine MR and PET are already assested to evaluate brain tumors but they are both of limited value if advanced techniques are not applied and if there is no integration of anatomical and functional data. In our experience adding quantitative data such as ADC to conventional MR and semi-quantitative analysis to PET with aminoacid tracers like DOPA is necessary for a better comprehension of tumor nature. In the era of molecular imaging this is a novel approach that could be introduced as a non-invasive marker of specific genomic patterns
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
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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