1,720,960 research outputs found
[Computerized tomography in the evaluation of the larynx after surgical treatment and irradiation].
No full textThe follow-up of the patients submitted to surgery for laryngeal carcinoma requires both clinical and CT examinations, particularly in the cases at high risk of recurrence. Our series consisted of 72 laryngeal carcinoma patients operated on and regularly followed-up with CT to distinguish relapse from normal or abnormal postoperative changes. Seventy-two laryngeal carcinoma patients were submitted to surgery: total laryngectomy was performed in 33 cases, supraglottic laryngectomy in 16 cases, Labayle subtotal laryngectomy in 18 cases and Mayer Piquet subtotal laryngectomy in 5 cases. The patients were followed-up postoperatively with CT and 94 examinations were performed in all; pathology was performed in all the cases with radiologic suspicion of recurrence (19 patients) and further clinical examinations were performed to exclude recurrence in the 14 cases where imaging findings were questionable. Local recurrences were confirmed in 16 of 19 patients with positive CT findings. Radiologically, the recurrence appeared as an irregular thickening of the pharyngo-laryngeal wall with inhomogeneous density after i.v. contrast agent infusion. The patients submitted to total or supraglottic laryngectomy recurred most often at the cranial site of resection (5/6 cases), those submitted to Labayle surgery at the mucosa adjacent to the cricoarytenoid unit (3/3 cases) and those submitted to Mayer Piquet surgery in the supraglottic region. Two more patients submitted to emergency tracheotomy recurred at this level. Lymph node recurrences were found in 6 total laryngectomy patients. Misinterpretations were most frequently due to postirradiation changes (5 of 14 cases) or to atypical postoperative images (4/14 cases). Three more patients presented a secondary lesion misinterpreted as a relapse. Our results confirm the role of CT in the follow-up of the patients operated on for laryngeal carcinoma when CT findings are closely correlated with clinical and endoscopic results, permitting to correctly assess the extent of relapse and possible nodal spread
Trattamento del carcinoma polmonare non microcitoma: esperienza della Divisione di Radioterapia dell'Università"La Sapienza" di Roma
No full text[Assessment of complications in patients with lung transplantation with high resolution computerized tomography].
No full textHigh Resolution Computed Tomography (HRCT) has been used by many authors to study the early complications of lung transplantation. Bronchoscopy, transbronchial biopsy and the clinical parameters are the tools of choice to diagnose such complications; HRCT showed excellent sensitivity (100\%) and good specificity (93\%) especially in detecting bronchial stenoses. We report the preliminary results of HRCT in detecting early/late complications in lung transplant recipients.Sixteen lung transplant recipients (5 single and 11 double transplants) were examined with HRCT at the Servizio Speciale Diagnostica V of "La Sapienza" University (Rome, Italy). The CT findings were compared with the results of bronchoscopy and respiratory function tests. The patients (8 men and 8 women; age range: 18-57 years, mean: 37.5) had cystic fibrosis (9), emphysema (3), alpha-1-antitrypsin deficiency (1), idiopathic pulmonary fibrosis (2), and bronchiectasis (1).During the follow-up, one patient died of pulmonary edema. CT findings were normal in 3 patients and mild pleural effusion was seen in 2. The other HRCT findings were: bronchial stenosis in 5 cases (which was bilateral in 1) and bronchial dehiscence in 1 patient; four cases of infection (1 CMV, 1 aspecific bacterial pneumonia, 1 Chlamydia psittacea and 1 Aspergillosis) and one of brochiolitis obliterans. A patient was treated for acute and one for chronic rejection. A CMV infection involved only the native lung in a patient. CT is easy to perform and a repeatable and well-tolerated tool with high sensitivity (100\%) and good specificity (93\%) in the early diagnosis of complications, particularly bronchial stenoses, which complications are often missed at bronchoscopy or clinically silent. CT should be always performed before bronchoscopy because it can provide valuable information for bronchoscopy targeting.In agreement with other authors we consider HRCT a very useful tool in the early diagnosis of the complications following lung transplantation
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
[Comparison of computerized tomography and magnetic resonance in staging of T and N parameters in head and neck neoplasms].
No full textJanuary 1990, through January 1994, eighty untreated patients with head and neck cancer were consecutively submitted to CT and MRI of the head and neck before surgery. CT and MR findings were then compared to operative histologic findings. Forty-eight of 52 T4 cases at CT were confirmed at surgery (89%), 7 of 13 T3 cases at CT were also confirmed (54%), as well as 8 of 15 T2 cases (53%). CT understaged 13 cases (6 T3 and 7 T2), which surgery staged as T4, CT overstaged 4 cases as T4, which were 2 pT2 and 2 pT3 at histology. All the 54 cases MRI staged as T4 were confirmed at surgery (100%), 3 of 12 MRI staged as T3 were pT4 at surgery (25%) and, finally, 4 of 14 cases MRI staged as T2 were pT4 at histology (28%). Only one case staged as pT4 at surgery and CT had been staged as T3 by MRI because the latter method had failed to depict hyoid involvement. On the other hand, in 6 cases MRI correctly modified CT staging. Overall CT accuracy was 79% and MR accuracy 91%. CT sensitivity was 70% versus 75% with MRI, specificity was 80% versus 78%, respectively, and overall accuracy 75% versus 76%. Only in two patients MRI correctly modified CT staging (N1 at surgery). Our results confirm various advantages of MRI over CT in the assessment of tumor mass ("T" parameter), mainly in T2 and T3 cases, because MRI yields higher soft tissue contrast resolution and has multiplanar capabilities. CT was superior to MRI only in the assessment of bone involvement. This study also confirmed similar CT and MR capabilities in detecting lymph node tumor spread. Finally, MRI did not allow earlier detection of micrometastases than CT
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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