1,720,991 research outputs found
Medication-Related Osteonecrosis of the Jaw-Comparison of Bone Imaging Using Ultrashort Echo-Time Magnetic Resonance Imaging and Cone-Beam Computed Tomography
Get PDFOBJECTIVE
The aim of this study was to compare bone imaging between ultrashort echo-time (UTE) magnetic resonance (MR) imaging and cone-beam computed tomography (CBCT) as the reference standard in patients with medication-related osteonecrosis of the jaw (MRONJ).
MATERIALS AND METHODS
A 1-year retrospective, blinded, and randomized qualitative analysis of UTE MR images and CBCT from 19 patients with clinically diagnosed MRONJ was performed by 2 independent radiologists. Medication-related osteonecrosis of the jaw imaging hallmarks such as osteolysis, periosteal thickening, and medullary osteosclerosis were rated visually (0 and 1 to 3 for normal and mild to severe changes) for defined anatomic regions of the jaw. In addition, segmentation of these regions was performed on coregistered MR/CBCT images for the following quantitative comparison of signal intensity (SI) on MR and gray values (GVs) on CBCT images. Interreader/modality agreement (Cohen kappa), standard testing for significant differences of (non)parametric values, and Pearson correlation of signal intensity/GV were used for statistical analysis.
RESULTS
The anterior corpus of the mandible was most often affected by MRONJ (P < 0.001). Overall, interreader agreement of qualitative MRONJ hallmark scores was almost perfect (κ = 0.81) and without significant differences between modalities (κ = 0.81 vs 0.82, CBCT vs MR, respectively). Intermodality agreement for qualitative gradings was substantial for both readers (κ = 0.77 and 0.70). Signal intensity/GV in MRONJ-affected areas differed significantly from healthy bone (P < 0.001) as well as correlation significantly between modalities (r = -0.77; P < 0.001).
CONCLUSIONS
Qualitative assessment of MRONJ with radiation-free UTE MR imaging is comparable to reference standard CBCT. Quantitative measurements of both modalities significantly distinguish diseased from normal bone with strong correlations among the quantitative values in both modalities
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
Performances of low-dose dual-energy CT in reducing artifacts from implanted metallic orthopedic devices
No full textOBJECTIVES: The objective was to evaluate the performances of dose-reduced dual-energy computed tomography (DECT) in decreasing metallic artifacts from orthopedic devices compared with dose-neutral DECT, dose-neutral single-energy computed tomography (SECT), and dose-reduced SECT.
MATERIALS AND METHODS: Thirty implants in 20 consecutive cadavers underwent both SECT and DECT at three fixed CT dose indexes (CTDI): 20.0, 10.0, and 5.0 mGy. Extrapolated monoenergetic DECT images at 64, 69, 88, 105, 120, and 130 keV, and individually adjusted monoenergy for optimized image quality (OPTkeV) were generated. In each group, the image quality of the seven monoenergetic images and of the SECT image was assessed qualitatively and quantitatively by visually rating and by measuring the maximum streak artifact respectively.
RESULTS: The comparison between SECT and OPTkeV evaluated overall within all groups showed a significant difference (p <0.001), with OPTkeV images providing better images. Comparing OPTkeV with the other DECT images, a significant difference was shown (p <0.001), with OPTkeV and 130-keV images providing the qualitatively best results. The OPTkeV images of 5.0-mGy acquisitions provided percentages of images with scores 1 and 2 of 36 % and 30 % respectively, compared with 0 % and 33.3 % of the corresponding SECT images of 10- and 20-mGy acquisitions. Moreover, DECT reconstructions at the OPTkeV of the low-dose group showed higher CT numbers than the SECT images of dose groups 1 and 2.
CONCLUSIONS: This study demonstrates that low-dose DECT permits a reduction of artifacts due to metallic implants to be obtained in a similar manner to neutral-dose DECT and better than reduced or neutral-dose SECT
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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