1,721,050 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
Upper limb anatomy and preoperative mapping J.VascJ Vasc Access. 2021 Nov;22(1_suppl):9-17. doi: 10.1177/11297298211046827. Epub 2021 Sep 27
No full textUltrasound in clinical setting of secondary hyperparathyroidism.
No full textSecondary hyperparathyroidism (sHPT) is one of the most common and serious complications of chronic kidney disease (CKD) and maintenance hemodialysis (MHD). In sHPT, the biology of parathyroid cells changes significantly toward diffuse and nodular hyperplasia. Diagnosis and treatment of sHPT are based on intact parathyroid hormone (i-PTH) serum levels and on the parameters of mineral metabolism. The morphological diagnosis of sHPT relies on 2 complementary imaging techniques: high-resolution ultrasonography with color Doppler imaging (US/CD) and 99mTc-methoxyisobutylisonitrile (MIBI) scintigraphy. The main objective of this review is to stimulate nephrologists to use US/CD of the parathyroid glands during the progression of CKD in order to aid clinical, pharmacological and surgical strategies. The primary role of US/CD in sHPT should be to integrate the clinical diagnosis by defining the number and volume of hyperplastic glands, although the international guidelines do not state when and why to perform US/CD. This review also evaluates the role of US/CD in clinical follow-up and assessment of therapeutic response of sHPT, and it highlights how US/CD can evaluate the effect of therapy with phosphate binders, vitamin D or its analogues and calcimimetics, which are changing the natural history of sHPT and the frequency of parathyroidectomy. Evaluation of the morphological and vascular changes of hyperplastic parathyroids is useful to guide percutaneous ethanol injection therapy and to support clinical, pharmacological and surgical strategies. Epidemiological studies are needed to establish how US/CD could change the management of sHPT and why it should be repeated in patients with high levels of serum i-PTH
Current role of ultrasound in hemodialysis access evaluation
Full text link: Physical examination (PE) is considered the backbone before vascular access (VA) placement, during maturation period and for follow-up. However, it may be inadequate in identifying suitable vasculature, mainly in comorbid patients, or in detecting complications. This review highlights the advantages of ultrasound imaging to manage VA before placement, during maturation and follow-up. Furthermore, it analyses the future perspectives in evaluating early and late VA complications thank to the availability of multiparametric platforms, point of care of ultrasound, and portable/wireless systems. Technical improvements and low-cost systems should favor the widespread ultrasound-based VA surveillance programs. This significant turning point needs an adequate training of nephrologists and dialysis nurses and the standardization of exams, parameters, and procedures
Advances in vascular anatomy and pathophysiology using high resolution and multiparametric sonography
Full text link: B-mode and Color Doppler are the first-line imaging modalities in cardiovascular diseases. However, conventional ultrasound (US) provides a lower spatial and temporal resolution (70-100 frames per second) compared to ultrafast technology which acquires several thousand frames per second. Consequently, the multiparametric ultrafast platforms manage new imaging algorithms as high-frequency ultrasound, contrast-enhanced ultrasound, shear wave elastography, vector flow, and local pulse wave imaging. These advances allow better ultrasound performances, more detailed blood flow visualization and vessel walls' characterization, and many future applications for vascular viscoelastic properties evaluation.In this paper, we provide an overview of each new technique's principles and concepts and the real or potential applications of these modalities on the study of the artery and venous anatomy and pathophysiology of the upper limb before and after creating a native or prosthetic arterio-venous fistula. In particular, we focus on high-frequency ultrasound that could predict cannulation readiness and its potential role in the venous valvular status evaluation before vascular access creation; on contrast-enhanced ultrasound that could improve the peri-operative imaging evaluation during US-guided angioplasty; on shear wave elastography and local pulse wave imaging that could evaluate preoperative vessels stiffness and their potential predictive role in vascular access failure; on vector flow imaging that could better characterize the different components of the vascular access complex flow
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
Free-hand ultrasound-guided renal biopsy: report of 650 consecutive cases.
No full textIn the past 4 years we have carried out 650 percutaneous renal biopsies (PRB), 54 on transplanted and 596 on native kidneys. PRB was performed with a 14-gauge one-piece disposable needle that was introduced free-handedly into the lumbar wall without any form of fixed guidance or support. Ultrasound was used to locate the kidney pole and to follow the progression of the needle tip in the renal parenchyma. The time needed for the whole procedure was about 5 min. The tissue specimen was adequate for histological evaluation in 98.8% of the cases. The prevalence of post-biopsy complications (haematuria, pain, anaemia) was 2.5%. Haematuria was not a common complication (1.6%) in our series, whereas clinically silent perirenal haematoma was common. Mild perirenal bleeding (volume < 5 ml) was found in 40 of a series of 150 patients (26.6%) who underwent ultrasound scan 24 h after the PRB. Haematoma exceeding 100 ml was revealed with US in only 0.6% of the patients. We conclude that free-hand ultrasound-guided PRB makes this technique easier, highly successful, time-saving and almost free of severe side effects
- …
