1,721,052 research outputs found
MEOLA M, PETRUCCI I, CALLIADA F, BARSOTTI M, PUCCINI M, GROSSO M, BARSOTTI G.: Presurgical Setting of Secondary Hyperparathyroidism Using High-Resolution Sonography and Color Doppler.
No full textPurpose: High-resolution sonography (US) with
color Doppler imaging (CDI) is a simple, noninvasive,
safe and repeatable technique able to highlight
the presence of hyperplastic parathyroid
glands and changes in their volume, structure,
and vascularization during uremia. The primary
aim of this study was to assess the diagnostic accuracy
of US and the sensitivity for localizing
parathyroid glands with a volume ≥ 500mm3.
The secondary aim was to assess the parameters
that define parathyroid glandular perfusion.
Materials and Methods: The diagnostic use of US
was assessed in 40 consecutive uremic patients
with severe secondary hyperparathyroidism
(sHPT) who were receiving maintenance hemodialysis
or conservative therapy with a hypoproteic-
hypophosphoric diet and had undergone
parathyroidectomy. Prior to surgery 99mTC-sestamibi
scintigraphy (SM) was performed in all
patients.
Results: The sensitivity, specificity, positive predictive
value and accuracy of US were 74%, 75%,
98%, and 74%, respectively. The sensitivity for localizing
glands with a volume ≥ 500mm3 was
90%. US and SM had a combined sensitivity of
83%. The vascularization of parathyroid glands
became more evident with increasing glandular
volume. With CDI, the signs of hypervascularization
(i.e. an enlarged feeding artery at the hilum,
a peripheral arc of vascularity and/or ray-like endonodular
vessels) were present in 77% of glands
with a volume ≥ 500mm3.
Conclusion: The sensitivity of US is higher than
that of SM, but it cannot be compared with that
of parathyroidectomy (74 vs. 95%). However, US/
CDI is able to characterize glands with different
volumes and vascular patterns. Since glandular
volume and vascularization are indicative of the
severity of sHPT, this study suggests that the
main role of US/CDI in the setting of sHPT should be to complete the diagnosis and to evaluate the morphological
changes of enlarged glands during uremia in order to define surgical timing, rather than to assess the presurgical location of
glands
Share-wave elastography study of myotendinous junction of the medial gastrocnemius: normal patterns and dynamic evaluation in professional football players
No full text
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
New prospects for ultrasound contrast agents
No full textConsidering the several suggestions regarding the future developments of echocontrast agents, there is a striking difference between the few compounds actually available on the market and used in clinical practice and those undergoing experimental clinical trials. It is therefore difficult to predict what will be the actual impact of these agents in the next future. Future developments will probably go beyond color enhancement which was the end-point till a very short time ago. They can be schematically summarized as follows: (1) development of new substances which enhance both color and gray scales; (2) use of new-generation substances, such as BR1 (Bracco, Milan, Italy) and EchoGen (Sonus, Bothell, WA), which use a gas other than air, such as perfluorate compounds which are more stable and guarantee longer and stronger effects; (3) use of more complex compounds acting at different levels. For example, SHU 536A (Sonovist) produces resonance phenomena with the second and third harmonics, and also stimulated acoustic emission which permits the morphological study of liver parenchyma. Other promising compounds are liposomes and aerosomes. Among the new possibilities in recording and observing phenomena, we can distinguish two main application fields: one is based on the physics of ultrasound and related to the presence of microbubbles in an acoustic field. These phenomena are generally obtained increasing the emission acoustic pressure, which eventually results in microbubble destruction and they are called nonlinear because there is no direct relationship between emission and return frequencies. These phenomena, which are detectable only with dedicated equipment, include: the resonance phenomenon with harmonic emission; intermittent harmonic emission and stimulated acoustic emission. The other application field is not strictly related to ultrasound physics and includes all the systems which can detect the presence of microbubles qualitatively or quantitatively. Other possible applications are related to the possibility of acquiring not only morphological but also functional data, especially in cardiology and neurology. Finally, targeted agents are potentially capable of demonstrating receptor sites or specific molecules, which may open very interesting therapeutic routes
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
Use of contrast-enhanced intraoperative ultrasonography during liver surgery for colorectal cancer liver metastases - Its impact on operative outcome. Analysis of a prospective cohort study
No full text- …
