1,721,143 research outputs found
Recommended from our members
A Faster R-CNN Model for Detection of MR-Compatible Catheters
Full text linkThis project sought to create a deep learning model to detect and track MR-compatible catheter tips under Magnetic Resonance Imaging. Interventional MRI, or iMRI, has many advantages over traditional x-ray angiography methods, yet the path towards adoption is hindered by many obstacles, including the lack of easily visualizable catheter tips. The model, the Faster Region-based Convolutional Neural Network (Faster R-CNN), was chosen due to its well-balanced speed and accuracy over other model architectures. The dataset included MR images of passive and resonant catheter tips alone and as well as passive catheter tips in an abdominal aorta phantom. The Faster R-CNN was trained over many iterations and over the best run it was able to draw bounding boxes over the tip of the catheter with an overall mean average precision of 0.59 and overall average recall of 0.66. Further optimization of training parameters will be needed to create a model that can achieve a better mean average precision. This study opens the possibility of applying artificial intelligence models towards iMRI methods, which helps push towards the goal of proving the safety and efficacy of iMRI procedures. These foundational elements are critical to smoothing the adoption of iMRI for guiding endovascular procedures
Recommended from our members
Simulations of RF Probes for Endovascular MRI using the Finite Element Method
Full text linkThe positioning of surface receiver coils limits the signal-to-noise ratio (SNR) of MRI. Endovascular RF imaging coils placed at or near the region of interest can image at greatly enhanced SNR compared with surface coils. Treatment protocols for neurovascular and cardiovascular diseases and conditions would benefit from better image quality. A series of numerical simulations using the Finite Element Method (FEM) of the electric and magnetic fields of endovascular RF probes of the looped and loopless (antenna) kinds were performed in order to assess their imaging performances and to improve their designs at the imaging strength of 3T. Safety of the probes was also considered. Emphasis is placed on simulations of a loopless coil, with and without the addition of an extremely high dielectric coating. A new design concept for actively tracking the distal end of a loopless coil is proposed, where signal dropout normally prevents its visualization and localization. This would be one of the few available multi-functional coils which could be used for imaging and tracking. The design consists of a corkscrew shaped inductive loop placed at the end of the loopless coil (maintaining an open circuit), with its axis oriented in the xy plane, allowing for signal gain in the axis of the loop. Electric and magnetic fields were mapped and preliminary SNRs and Specific Absorption Rates (SARs) are presented, showing the corkscrew's viability as a potential active tracking mechanism
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
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
- …
