1,721,158 research outputs found
Guida per posizionamento di cateteri cerebrali
No full textBackground: external ventricular drain (EVD) placement is mandatory for several pathologies. The misplacement rate of the EVD in the literature varies widely, ranging from 12.3% to 60%. The purpose of this study is to provide preliminary data about the possibility of increasing the safety of one of the most common life-saving procedures in neurosurgery by testing a new device for EVD placement.
Methods: we used a novel guide for positioning the ventricular catheter (patent RM2014A000376). The trajectory was assessed using 25 anonymized head CT scans of patients. The data set were used to con-duct three-dimensional computer-based and combined navigation and augmented reality-based simulations using plaster models. The data set inclusion criteria were volumetric head CT scan without midline shift of patients who are above 18 years old. Evans ratio was used to quantify the ventricle’s size. We excluded patients with slit ventricles, midline shift, skull fractures, and complex skull malformations. The proximal end of the device was tested on the cadaver.
Results: the cadaveric tests proved that only one surgeon could use the device. The multimodal simulation showed Kakarla grade 1 in all cases but one with grade 2, on both sides after right and left EVD placement. The mean Evans ratio was 0,28. The geometric principles that explain the device's efficacy can be summarized by studying the geometric properties of circumference and chord. The contact occurs for each section considered at the extreme points of the chord. Its axis, perpendicular to the plane tangent to the spherical surface at the entry point, corresponds to the direction of entry of the catheter guided by the instrument.
Conclusions: according to our multimodal simulation through cadaveric, 3D computer-based simulation, 3D plaster modeling, 3D neuronavigation, and augmented reality, the device will offer safer and effective EVD placements
One Fell Swoop: Septic Muscle Embolism and Central Venous Catheter Infection Imaged with [18F] Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography
No full textWe describe the case of a 43-year-old female with hereditary hemochromatosis, previously without cardiac issues, who presented with a severe fever (>40 to 41 °C) to our hospital. Initial assessments, including transthoracic echocardiography, showed no typical signs of infective endocarditis. A contrast-enhanced CT scan revealed a hypodense area in the right subscapular muscle, alongside pleural thicknesses. Due to the critical condition, a central venous catheter (CVC) was implanted for immediate intravenous treatment. Subsequent blood cultures, positive for Staphylococcus aureus, and transesophageal echocardiography led to a diagnosis of multivalvular infective endocarditis (MIE). Subsequently, the patient underwent positron emission tomography/computed tomography (PET/CT) with [18F]Fluorodeoxyglucose ([18F]FDG), which detected increased tracer incorporation in the muscle lesion, CVC, and pleural thicknesses. The final diagnosis was CVC infection and septic embolism to the subscapular muscle in a patient with pleuritis. This case showcases the critical role of [18F]FDG PET/CT as whole-body imaging modality in diagnosing and managing complex infective cases
Angel-shaped phalanges in brachydactyly C: a case report, and speculation on pathogenesis. Pediatr Radiol. 2005 May;35(5):535-8. Epub 2004 Nov 23
No full textGoing 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
Imaging Epigenetics in Alzheimer's Disease
No full textSporadic Alzheimer's disease (AD) is a prevalent, complex and chronically progressive brain disease. Its course is non-linear, dynamic, adaptive to maladaptive, and compensatory to decompensatory, affecting large-scale neural networks through a plethora of mechanistic and signaling pathway alterations that converge into regional and cell type-specific neurodegeneration and, finally, into clinically overt cognitive and behavioral decline. This decline includes reductions in the activities of daily living, quality of life, independence, and life expectancy. Evolving lines of research suggest that epigenetic mechanisms may play a crucial role during AD development and progression. Epigenetics designates molecular mechanisms that alter gene expression without modifications of the genetic code. This topic includes modifications on DNA and histone proteins, the primary elements of chromatin structure. Accumulating evidence has revealed the relevant processes that mediate epigenetic modifications and has begun to elucidate how these processes are apparently dysregulated in AD. This evidence has led to the clarification of the roles of specific classes of therapeutic compounds that affect epigenetic pathways and characteristics of the epigenome. This insight is accompanied by the development of new methods for studying the global patterns of DNA methylation and chromatin alterations. In particular, high-throughput sequencing approaches, such as next-generation DNA sequencing techniques, are beginning to drive the field into the next stage of development. In parallel, genetic imaging is beginning to answer additional questions through its ability to uncover genetic variants, with or without genome-wide significance, that are related to brain structure, function and metabolism, which impact disease risk and fundamental network-based cognitive processes. Neuroimaging measures can further be used to define AD systems and endophenotypes. The integration of genetic neuroimaging methods with epigenetic markers in humans appears promising. This evolving development may lead to a new research discipline - imaging epigenetics - that will provide deeper insight into the causative pathogenetic and pathophysiological pathways through which genes and environment interrelate during life and impact human brain development, physiology, aging and disease. This knowledge may open doors for the development of novel biomarkers and preventive and disease-modifying treatments
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
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