1,720,980 research outputs found
Ultra-low-dose chest CT in adult patients with cystic fibrosis using a third-generation dual-source CT scanner
No full textIntroduction: Chest computed tomography (CT) examinations are performed routinely in some cystic fibrosis (CF) centers in order to evaluate lung disease progression in CF patients. Continuous CT technological advancement in theory could allows a lower radiation exposure of CF patients during chest CT examinations without an image quality reduction, and this could become increasingly important over time in order to reduce the cumulative radiation dose effects given the continuous increase of CF patients predicted median survival. Objective: The aim of this study was to compare objective and subjective image quality and radiation dose between low-dose chest CT examinations performed in adult CF patients using a third-generation DSCT scanner and a 64-slices single-source CT (SSCT) scanner. Materials and methods: Between January 2016 and August 2019, 81 CF patients underwent low-dose chest CT examinations using both a 64-slices SSCT scanner (2016–2017) and a third-generation DSCT scanner (2018–2019). Objective image noise standard deviation (INSD), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), overall subjective image quality (OSIQ), subjective image noise (SIN), subjective evaluation of streaking artifacts (SA), movement artifacts (MA) and edge resolution (ER), dose-length product (DLP), volume computed tomography dose index (CTDIvol) and effective radiation dose (ERD) were compared between DSCT and SSCT examinations. DSCT examinations consisted in spiral inspiratory end expiratory acquisitions. SSCT examinations consisted in spiral inspiratory acquisitions and five axial expiratory ones. Results: DSCT protocol showed statistically significant lower spiral inspiratory phase mean DLP, CTDIvol and ERD than SSCT protocol, with a 25% DLP, CTDIvol and ERD reduction. DSCT protocol showed statistically significant higher overall (inspiratory and expiratory phases) mean DLP, CTDIvol and ERD than SSCT protocol, with a 40% DLP, CTDIvol and ERD increase. Objective image quality (INSD, SNR and CNR) and SIN differences were not statistically significant, but subjective evaluation of DSCT images showed statistically significant better OSIQ and ER, as well as statistically significant lower SA and MA with respect to SSCT images. Conclusions: To our knowledge, this is the first study evaluating chest CT image quality and radiation dose in adult CF patients using a third-generation DSCT scanner, and it showed that technological advancements could be used in order to reduce radiation exposure of volumetric examinations. The spiral inspiratory dose reduction can be obtained with concomitant improvements in subjective image quality with comparable objective quality. This will probably allow a wider use of this imaging modality in order to assess bronchiectasis and will probably foster spiral expiratory acquisition for small airways disease evaluation
Apparent diffusion coefficient values in borderline breast lesions upgraded and not upgraded at definitive histopathological examination after surgical excision
No full textPurpose: The study aims were to evaluate if the apparent diffusion coefficient (ADC) value could distinguish between breast lesions classified as B3 at core needle biopsy (CNB) that show or do not show atypia or malignancy at definitive histopathological examination (DHE) after surgical excision. Material and methods: From January 2013 to December 2017, 141 patients with a B3 breast lesion underwent magnetic resonance imaging and were included in the study. The ADC value was assessed drawing a ROI outlining the entire lesion, evaluating the mean (ADCmean ) and minimum ADC values (ADCmin ). Results: Both ADCmean and ADCmin values showed a statistically significant difference between B3 lesions without and with malignancy or, for B3a lesions, atypia at DHE. They both showed a statistically significant difference also between B3a lesions without or with atypia or malignancy at DHE, but only ADCmin (not ADCmean ) showed statistically significant difference between B3b lesions without or with malignancy at DHE. Conclusions: The ADC value could help distinguish between B3a lesions without or with atypia/malignancy at DHE after surgical excision and between B3b lesions without or with malignancy at DHE. Therefore, it could be used to help guide the diagnostic-therapeutic pathway of these lesions, particularly of B3a lesions
Contrast-enhanced ultrasound evaluation of testicular syphilis: A case report
No full textIn North America and Europe, syphilis incidence has increased dramatically in the past decade among high-risk groups. Syphilis may occur in any organ, including the testis. There are not many cases of testicular syphilis assessed by means of ultrasound examination described in the literature, and in no case was the evaluation carried out using advanced ultrasound techniques. Here we present a case of testicular syphilis evaluated by contrast-enhanced ultrasound
Apparent diffusion coefficient value in breast papillary lesions without atypia at core needle biopsy
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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
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