1,720,966 research outputs found
Imaging of the Ageing Spine
No full textPurpose of Review: The purpose of this review was to desccribe the main processes related to the ageing spine, studied through different imaging methods. Recent Findings: Degenerative changes in the spine represent a progressive and irreversible involutionary process. They are constantly growing in relation to the increase in the average age of the population; therefore, they constitute an important health problem with enormous socio-economic significance. Summary: The role of the radiologist is fundamental in the evaluation of degenerative processes affecting the bone and intervertebral discs and in the diagnosis of complications
Postmenopausal osteoporosis: current status of bone densitometry
No full textOsteoporosis is the most common of all metabolic bone disorders characterized by loss of bone strength, due to modifications in bone turnover. It leads to bone fragility and increased fracture risk. Because of the increasing aging of the world population, the number of people affected by osteoporosis is continuously increasing. The WHO operational definition of osteoporosis, based on a measurement of bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA), identifies patients at greatest risk of fracture. However, in the population overall a greater total number of fractures occurs in individuals with BMD values above threshold for osteoporosis diagnosis; for this reason, algorithms have been developed to improve the identification of individuals at high fracture risk, including clinical risk factors for fracture. The correct diagnosis of osteoporosis with an appropriate and accurate use of diagnostic imaging results in better management in terms of adequate treatment and follow-up. Moreover, screening strategies will improve identification of patients who are most likely to benefit from drug treatment to prevent fracture. All women after the age of 65 years previously untested and women after the age of 50 years with previous low trauma fractures should be screened by DXA. In fact, osteoporosis-related fractures cause a significant increase in morbidity and mortality, decreasing the quality of life, with an increasing social and economic burdens. For this reason, fracture risk assessment should be a high priority amongst health measures
Hoffa’s fat pad thickness: a measurement method with sagittal MRI sequences
Full text linkBackground: Hoffa’s fat pad is a structure located within the fibrous joint capsule of the knee joint, but outside the synovial cavity. It plays an important biomechanical and metabolic role in knee joint, reducing the impact of forces generated by loading and producing cytokines. Changes in its size can induce modifications in the knee homeostasis. However, a great variability exists regarding its measurements. This work aims to evaluate the reliability of a measurement method of Hoffa’s fat pad dimensions through MRI. Methods: 3T sagittal IW 2D TSE fat-suppressed MRI sequences, taken from the OAI (Osteoarthritis initiative) database, of 191 male and female patients, aged between 40 and 80 years, were analysed; a manual measurement of the thickness of Hoffa’s fat pad of each subject was then performed by two different readers. The interobserver reliability and intraobserver reliability of the measurements were described by coefficient of variation (CV), Pearson correlation and Bland–Altman plots. Results: All statistical analyses have shown that not significant intra- or interobservers differences were evident (intraobserver CV % for the first observer was 2.17% for the right knee and 2.24% for the left knee, while for the second observer 2.31% for the right knee and 2.24% for the left knee; linear correlation was for the first observer r = 0.96 for the right knee and r = 0.96 for the left knee, while for the second observer r = 0.97 for the right knee and r = 0.96 for the left knee; in addition, the interobserver CV % was 1.25% for the right knee and 1.21% for the left knee and a high interobserver linear correlation was found: r = 0.97 for the right knee and r = 0.96 for the left knee). All results suggest that this manual measurement method of Hoffa’s fat pad thickness can be performed with satisfactory intra- and interobserver reliability. Conclusions: Hoffa’s fat pad thickness can be measured, using sagittal MRI images, with this manual method that represents, for his high reliability, an effective means for the study of this anatomical structure. © 2021, The Author(s)
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
A rare sacral localization of giant cell tumor in a young adult female: a case report
No full textWe reported the case of a 42-years-old woman who suffered from a giant cell tumor of sacrum. Although the giant cell tumor primarily affects the long bones, especially those of the knee joint, it can rarely affect the axial skeleton and the sacrum. The onset of symptoms is generally insidious and may include locoregional pain and swelling as well as movement deficits if nerve roots are involved at this level. In this case report we discuss on the radiographic imaging, computed tomography and magnetic resonance imaging features of this type of tumor in an unusual location of the disease
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