1,720,957 research outputs found
Distribution of solid solitary pulmonary nodules within the lungs on computed tomography : a review of 208 consecutive lesions of biopsy-proven nature
No full textBACKGROUND: The solitary pulmonary nodule (SPN) is a common radiologic abnormality on chest x-rays or computed tomography (CT) scans of the lungs. The differential diagnosis of SPNs is particularly wide as it includes a multitude of benign as well as malignant entities. Nodule location within the lungs has been proposed as a predictive feature in the literature.This study aims at illustrating the distribution within the lungs of a large current series of consecutive SPNs according to their histological subtype, which was definitely proved at core biopsy. MATERIAL AND METHODS: Two hundred-eight SPNs referred to our center for characterization were reviewed in this single-centre retrospective study. Histological subtypes were defined following the IASLC/ATS/ERS and WHO (2004) histological classification. RESULTS: This study provides evidence with respect to the prevalence of adenocarcinomas and other non-neuroendocrine primary lung cancer types in the right upper lobe. It also provides new evidence with respect to the prevalence of carcinoid tumors in the middle and right lower lobe, with a tendency to occur in the central lung parenchyma. CONCLUSIONS: This work updates existing knowledge of solid SPNs location within the lungs by providing a current picture of SPN distribution according to their nature
CT imaging features in the characterization of non-growing solid pulmonary nodules in non-smokers
No full textBACKGROUND: A disappearing or persistent solid pulmonary nodule is a neglected clinical entity that still poses serious interpretative issues to date. Traditional knowledge deriving from previous reports suggests particular features, such as smooth edges or regular shape, to be significantly associated with benignity. A large number of benign nodules are reported among smokers in lung cancer screening programmes. The aim of this single-center retrospective study was to correlate specific imaging features to verify if traditional knowledge as well as more recent acquisitions regarding benign SPNs can be considered reliable in a current case series of nodules collected in a non-smoker cohort of patients. MATERIAL AND METHODS: Fifty-three solid SPNs proven as non-growing during follow-up imaging were analyzed with regard to their imaging features at thin-section CT, their predicted malignancy risk according to three major risk assessment models, minimum density analysis and contrast enhanced-CT in the relative subgroups of nodules which underwent such tests. RESULTS: Eleven nodules disappeared during follow-up, 29 showed volume loss and 16 had a VDT of 1121 days or higher. There were 48 nodules located peripherally (85.71%). Evaluation of the enhancement after contrast media (n=29) showed mean enhancement ±SD of 25.72±35.03 HU, median of 18 HU, ranging from 0 to 190 HU. Minimum density assessment (n=30) showed mean minimum HU ±SD of –28.27±47.86 HU, median of -25 HU, ranging from -144 to 68 HU. Mean malignancy risk ±SD was 15.05±26.69% for the BIMC model, 17.22±19.00% for the Mayo Clinic model and 19.07±33.16% for the Gurney's model. CONCLUSIONS: Our analysis suggests caution in using traditional knowledge when dealing with current small solid peripheral indeterminate SPNs and highlights how quantitative growth at follow-up should be the cornerstone of characterization
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
Multifocal branch-duct intraductal papillary mucinous neoplasms (IPMNs) of the pancreas: magnetic resonance (MR) imaging pattern and evolution over time.
No full textPURPOSE:
The aim of our study was to follow the evolution over time of multifocal intraductal papillary mucinous neoplasms (IPMN) of the pancreatic duct side branches by means of magnetic resonance imaging (MRI).
MATERIALS AND METHODS:
A total of 155 patients with multifocal IPMN of the side branches were examined with MRI and MR cholangiopancreatography (MRI/MRCP). Inclusion criteria were patients with ≥2 dilated side branches involving any site of the parenchyma; presence of communication with the main pancreatic duct and previous investigations by MRI/MRCP within at least six months. Median follow-up was 25.8 months (range, 12-217). Patients with a follow-up period shorter than 12 months (n=33) and those with a diagnosis of multifocal IPMN of the side branches without any follow-up (n=14) were excluded from the study. The final study population thus comprised 108 patients. A double, quantitative and qualitative, analysis was carried out. The quantitative image analysis included: number of dilated side branches in the head-uncinate process and body-tail; maximum diameter of lesions in the head-uncinate process; maximum diameter in the body-tail; maximum diameter of the main pancreatic duct in the head and body-tail. The qualitative image analysis included: presence of malformations or anatomical variants of the pancreatic ductal system; site of the lesions (head-uncinate process, body-tail, ubiquitous, bridge morphology); presence of gravity-dependent intraluminal filling defects; presence of enhancing mural nodules.
RESULTS:
At diagnosis, the mean number of cystic lesions of the side branches was 7.09. The mean diameter of the cystic lesions was 13.7 mm. The mean diameter of the main pancreatic duct was 3.6 mm. At follow-up, the mean number of cystic lesions was 7.76. The mean diameter of the cystic lesions was 13.9 mm. The mean diameter of the main pancreatic duct was 3.7 mm. Intraluminal filling defects in the side branches were seen in 18/108 patients (16.6%); enhancing mural nodules were seen in 3/108 patients (2.7%).
CONCLUSIONS:
Multifocal IPMN of the branch ducts shows a very slow growth and evolution over time. In our study, only 3/108 patients showed mural nodules which, however, did not require any surgical procedure, indicating that careful nonoperative management may be safe and effective in asymptomatic patients
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
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