1,720,966 research outputs found
The role of elastography in thyroid ultrasonography
No full textPURPOSE OF REVIEW:
Elastography is a novel noninvasive diagnostic tool that is helpful in the evaluation of thyroid nodules. The purpose of this review is to provide a comprehensive summary of the use of elastography in the clinical thyroid setting.
RECENT FINDINGS:
Initial and subsequent studies show that elastography has both a sensitivity and specificity that approaches 100% for the determination of thyroid cancer within a thyroid nodule. In addition, the technique also has a very high negative predictive value and thus, may also be helpful in identification of thyroid nodules that do not need further diagnostic evaluation, including fine-needle aspiration biopsy. These characteristics also apply to both strain and shear wave elastography. However, as both the extent of tissue compression and the operator's classification of a nodule using a qualitative color code are subjective, intra and interobserver variability is an important reason for some conflicting findings.
SUMMARY:
Elasticity within a thyroid nodule, as evaluated by elastography, offers diagnostic results that are equal to or sometimes even greater than that of conventional ultrasonography for the determination of thyroid malignancy. The integration of both techniques in the clinical work-up of thyroid nodules can thus significantly improve the accuracy of the diagnosis of thyroid nodules
Pulmonary sequestration: a 131I whole body scintigraphy false-positive result.
No full textA 35-year-old woman affected by a well-differentiated papillary thyroid carcinoma was referred to our hospital to perform a (131)Iodine ((131)I) whole body scintigraphy for restaging purpose. The patient had been previously treated with total thyroidectomy and three subsequent doses of (131)I for the ablation of a remnant jugular tissue and a suspected metastatic focus at the superior left hemi-thorax. In spite of the previous treatments with (131)I, planar and tomographic images showed the persistence of an area of increased uptake at the superior left hemi-thorax. This finding prompted the surgical resection of the lesion. Histological examination of the surgical specimen showed the presence of a pulmonary tissue consistent with pulmonary sequestration. Even though rare, pulmonary sequestration should be included in the potential causes of false-positive results of radioiodine scans
PETC/CT with 18F-Choline localizes hyperfunctioning parathyroid adenomas equally well in normocalcemic hyperparathyroidism as in overt hyperparathyroidism
No full textPURPOSE:
Identification of pathologic parathyroid glands in primary hyperparathyroidism, traditionally based on neck ultrasound (US) and/or 99mTc-Sestamibi scintigraphy, can be challenging. PET/CT with 18F-Fluorocholine (18F-FCH) might improve the detection of pathologic parathyroid glands. We aimed at comparing the diagnostic performance of 18F-FCH-PET/CT with that of dual-phase dual-isotope parathyroid scintigraphy and neck US.
METHODS:
Thirty-four consecutive patients with primary hyperparathyroidism were prospectively enrolled, 7 had normocalcemic hyperparathyroidism, and 27 had classic hypercalcemic hyperparathyroidism. All patients underwent high-resolution neck US, dual-phase dual-isotope 99mTc-Pertechnetate/99mTc-Sestamibi scintigraphy, and 18F-FCH-PET/CT.
RESULTS:
In the whole patients' group, the detection rates of the abnormal parathyroid gland were 68% for neck US, 71% for 18F-FCH-PET/CT, and only 15% for 99mTc-Sestamibi scintigraphy. The corresponding figures in normocalcemic and hypercalcemic hyperparathyroidism were 57 and 70% for neck US, 70 and 71% for 18F-FCH-PET/CT, and 0 and 18% for 99mTc-Sestamibi scintigraphy, respectively. In the 17 patients in whom the abnormal parathyroid gland was identified, either at surgery or at fine needle aspiration cytology/biochemistry, the correct detection rate was 82% for neck US, 89% for 18F-FCH-PET/CT, and only 17% for 99mTc-Sestamibi scintigraphy.
CONCLUSIONS:
18F-FCH-PET/CT can be considered a first-line imaging technique for the identification of pathologic parathyroid glands in patients with normocalcemic and hypercalcemic hyperparathyroidism, even when the parathyroid volume is small
Laser photocoagulation therapy for thyroid nodules: long-term outcome and predictors of efficacy
No full textPurpose: The aim of the present study was to retrospectively evaluate the efficacy of interstitial laser photocoagulation (ILP) ablation of thyroid nodules during a 6-year follow-up period and to identify possible predictors of the final outcome. Methods: Forty-three outpatients (38 women) were assigned to ILP therapy. The study group included euthyroid patients with benign thyroid nodules. Thyroid size, nodule volume and features, and autoimmune test were collected at baseline. Patients underwent US control after the ILP procedure and 1 month, 6 months, 12 months later and then annually. Results: During the follow-up, two distinct groups of patients emerged: the responders (N = 33) and the non-responder (N = 10) ones to ILP. In the responder group, the nodule volume significantly decreased during the follow-up, but a trend toward a slight increase in nodule volume was recorded up to the end of follow-up. No significant decrease in nodule volume was observed in the non-responder group. Neither baseline clinical nor demographic features were significantly different between responders and non-responders groups. In the whole group of patients, the energy delivered per mL of nodule tissue was significantly correlated with the percent volume decrease at the end of follow-up. Conclusions: Interstitial laser photocoagulation is a safe technique able to reduce byabout 50% the volume of benign thyroid nodules in the majority of treated patients. However, due to the great variability of results, an active follow-up is required. The only independent predictor of ILP outcome is the energy delivered per mL of nodule tissue
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
The post partum period and the onset of Graves' disease: an overestimated risk factor.
No full textOBJECTIVE: Aggravation of autoimmune diseases due to a rebound reaction to the pregnancy-associated immune changes is common during the post partum (PP) period. Previous studies demonstrated that up to 45% of women developing Graves' disease (GD) in the childbearing age had a PP onset of disease. Thus, the PP period was identified as a major risk factor for GD onset. DESIGN: The aim of this study was to evaluate the role of the PP period as a risk factor for GD occurrence. METHODS: The reproductive histories of 291 consecutive GD patients (165 patients in the childbearing age and 126 in the non-childbearing age) were retrospectively collected. RESULTS: The rate of PP onset of GD in all patients with at least one successful pregnancy was 9.8 and 20.0% when only patients in the childbearing age were considered. In the entire cohort of GD women, independent of their age and parity status (i.e., the number of successful pregnancies), the rate of PP onset of GD was 7.2%. The relative frequencies of the rate of PP onset of GD were similar in relation with increasing parity. The rates of false negative (nulliparous) and false positive (parous non-childbearing+childbearing with a non-PP onset of GD) were estimated. The positive predictive value of the PP period for the onset of GD was less than 10%. CONCLUSIONS: The results of the current study would not support a role for the PP period as a major risk factor for de novo occurrence of GD
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
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