1,720,965 research outputs found
Bolus versus continuous infusion of microbubble contrast agent for liver ultrasound by using an automatic power injector in humans: A pilot study
No full textPurpose. To evaluate the feasibility of using continuous infusion, in comparison with bolus injection, of a sulfur hexafluoride–microbubble contrast
agent to prolong the duration of hepatic parenchymal enhancement in humans during sonographic examination. Methods. This pilot study was approved by our institution’s ethics committee. Ten patients (5 men and 5 women; mean age 6 SD, 65 6 10 years) each received two injections: a bolus injection (2 ml/s) and then continuous infusion (0.5 ml/min) of the contrast agent by using an automatic injector. Acquired cine clips were transferred to a personal computer, and the video intensity was quantified by dedicated software. Results. From the time of the first microbubble visualization in the scanning plane, maximal enhancement was reached in 6.3 6 0.94 seconds after bolus injection and in 13.9 6 1.44 seconds during continuous infusion (p 5 0.002, Wilcoxon’s test for paired data). Compared with bolus injection, continuous infusion prolonged the duration of contrast enhancement (4.3 minutes 6 42 seconds versus 7.3 minutes 6 40 seconds; p 5 0.002), although no statistically significant difference in maximal
enhancement was observed (45 6 18% for bolus injection and 396 6%for continuous infusion; p50.62). Conclusions. Continuous infusion of sulfur hexafluoride–filled microbubbles via an automatic power injector prolongs hepatic contrast enhancement without significantly modifying the maximal enhancement over that at baseline. These data, coming from a pilot study, can be used to design a larger study with adequate statistical power
Bolus versus continuous infusion of microbubble contrast agent for liver ultrasound by using an automatic power injector in humans: A pilot study
No full textPurpose. To evaluate the feasibility of using continuous infusion, in comparison with bolus injection, of a sulfur hexafluoride–microbubble contrast
agent to prolong the duration of hepatic parenchymal enhancement in humans during sonographic examination. Methods. This pilot study was approved by our institution’s ethics committee. Ten patients (5 men and 5 women; mean age 6 SD, 65 6 10 years) each received two injections: a bolus injection (2 ml/s) and then continuous infusion (0.5 ml/min) of the contrast agent by using an automatic injector. Acquired cine clips were transferred to a personal computer, and the video intensity was quantified by dedicated software. Results. From the time of the first microbubble visualization in the scanning plane, maximal enhancement was reached in 6.3 6 0.94 seconds after bolus injection and in 13.9 6 1.44 seconds during continuous infusion (p 5 0.002, Wilcoxon’s test for paired data). Compared with bolus injection, continuous infusion prolonged the duration of contrast enhancement (4.3 minutes 6 42 seconds versus 7.3 minutes 6 40 seconds; p 5 0.002), although no statistically significant difference in maximal
enhancement was observed (45 6 18% for bolus injection and 396 6%for continuous infusion; p50.62). Conclusions. Continuous infusion of sulfur hexafluoride–filled microbubbles via an automatic power injector prolongs hepatic contrast enhancement without significantly modifying the maximal enhancement over that at baseline. These data, coming from a pilot study, can be used to design a larger study with adequate statistical power
Value of percent change in tumoral volume measured at T2-weighted and diffusion-weighted MRI to identify responders after neoadjuvant chemoradiation therapy in patients with locally advanced rectal carcinoma
No full textPurpose: To evaluate the percent change in tumoral volume measured at T2-weighted magnetic resonance imaging (T2WMRI) and diffusion-weighted (DWI) as a method to identify responders after chemo- and radiation therapy (CRT) in patients with locally advanced rectal carcinoma. Materials and Methods: Forty-five consecutive patients (mean age ± SD: 72 years ± 9.7; male/female = 24/21) with locally advanced rectal carcinoma underwent CRT followed by surgery. Each patient underwent T2WMRI and DWI at 1.5T before and 6 weeks after the completion of CRT. The percent change in tumoral volume before and 6 weeks after CRT was compared in patients classified as responders and nonresponders according to rectal cancer regression grade. Results: Twenty-five patients were classified as responders with either partial (n = 20) or complete response (n = 5), while 20 patients were classified as nonresponders due to stable disease (n = 18) or disease progression (n = 2). Responders vs. nonresponders differed in the percent change of tumoral volume at T2WMRI (−67% ± 26% vs. −29% ± 26%; P < 0.05) and DWI images (−72% ± 24% vs. −33% ± 28%; P < 0.05) with a cutoff ≤ −70% for T2WMRI (sensitivity = 69%, 95% confidence interval [CI]: 48−85%; specificity = 100%, 95% CI 81–100%) and ≤66% for DWI (sensitivity = 73%, 95% CI: 52–88%; specificity = 100%, 95% CI 81–100%). Conclusion: The percent change in tumoral volume at T2WMRI and DWI images can differentiate responders from nonresponders in patients with locally advanced rectal carcinoma after neoadjuvant CRT
Value of percent change in tumoral volume measured at T2-weighted and diffusion-weighted MRI to identify responders after neoadjuvant chemoradiation therapy in patients with locally advanced rectal carcinoma
No full textPurpose: To evaluate the percent change in tumoral volume measured at T2-weighted magnetic resonance imaging (T2WMRI) and diffusion-weighted (DWI) as a method to identify responders after chemo- and radiation therapy (CRT) in patients with locally advanced rectal carcinoma. Materials and Methods: Forty-five consecutive patients (mean age ± SD: 72 years ± 9.7; male/female = 24/21) with locally advanced rectal carcinoma underwent CRT followed by surgery. Each patient underwent T2WMRI and DWI at 1.5T before and 6 weeks after the completion of CRT. The percent change in tumoral volume before and 6 weeks after CRT was compared in patients classified as responders and nonresponders according to rectal cancer regression grade. Results: Twenty-five patients were classified as responders with either partial (n = 20) or complete response (n = 5), while 20 patients were classified as nonresponders due to stable disease (n = 18) or disease progression (n = 2). Responders vs. nonresponders differed in the percent change of tumoral volume at T2WMRI (−67% ± 26% vs. −29% ± 26%; P < 0.05) and DWI images (−72% ± 24% vs. −33% ± 28%; P < 0.05) with a cutoff ≤ −70% for T2WMRI (sensitivity = 69%, 95% confidence interval [CI]: 48−85%; specificity = 100%, 95% CI 81–100%) and ≤66% for DWI (sensitivity = 73%, 95% CI: 52–88%; specificity = 100%, 95% CI 81–100%). Conclusion: The percent change in tumoral volume at T2WMRI and DWI images can differentiate responders from nonresponders in patients with locally advanced rectal carcinoma after neoadjuvant CRT
Predictors of intrahepatic cholangiocarcinoma in cirrhotic patients scanned by gadobenate dimeglumine-enhanced magnetic resonance imaging: Diagnostic accuracy and confidence
No full textObjective: To identify predictors of intrahepatic cholangiocarcinoma in cirrhotic patients scanned by gadobenate dimeglumine (Gd-BOPTA)-enhanced magnetic resonance (MR) imaging. Methods: Fifty cirrhotic patients with 120 nodules, including 10 mass-forming intrahepatic cholangiocarcinomas and two combined hepatocellular carcinoma-cholangiocarcinomas, were scanned by Gd-BOPTA-enhanced MR imaging. Results: T1 hypointensity [odds ratio (OR), 20.12], peripheral hyperintense rim at hepatic arterial phase (OR, 13.5), and iso-hyperintensity at hepatobiliary phase (OR 21.32) were found to be independent predictors of intrahepatic cholangiocarcinoma. Conclusions: T1 hypointensity, peripheral hyperintense rim at hepatic arterial phase, and iso-hyperintensity at hepatobiliary phase are independent predictors of intrahepatic cholangiocarcinoma diagnosis in patients with liver cirrhosis. © 2015 Elsevier Inc
Time-intensity curves obtained after microbubble injection can be used to differentiate responders from nonresponders among patients with clinically active Crohn disease after 6 weeks of pharmacologic treatment
Full text linkPurpose: To assess whether contrast material-enhanced ultrasonography (US) can be used to differentiate responders from nonresponders among patients with clinically active Crohn disease after±weeks of pharmacologic treatment. Materials and Methods: This prospective study was approved by our ethics committee, and written informed consent was obtained from all patients. Fifty consecutive patients (26 men and 24 women; mean age, 34.76 years±9) with a proved diagnosis of active Crohn disease who were scheduled to begin therapy with biologics (infliximab or adalimumab) were included, with enrollment from June 1, 2013, to June 1, 2015. In each patient, the terminal ileal loop was imaged with contrast-enhanced US before the beginning and at the end of week±of pharmacologic treatment. Time-intensity curves obtained in responders (those with a decrease in the Crohn disease endoscopic index of severity score of 25-44 before treatment to 10-15 after treatment, an inflammatory score ,7, and/or a decrease ≥70 in the Crohn disease activity index score compared with baseline) and nonresponders were compared with Mann-Whitney test. Results: Responders (n = 31) and nonresponders (n = 19) differed (P , .05) in the percent change of peak enhancement (240.78±62.85 vs 53.21±72.5; P = .0001), wash-in (234.8±67.72 vs 89.44±145.32; P = .001) and washout (25.64±130.71 vs 166.83±204.44; P = .002) rate, wash-in perfusion index (242.29±59.21 vs 50.96±71.13; P = .001), area under the time-intensity curve (AUC; 246.17±48.42 vs 41.78±87.64; P = .001), AUC during wash-in (243.93±54.29 vs 39.79±70.85; P = .001), and AUC during washout (249.36±47.42 vs 42.65±97.09; P = .001). Responders and nonresponders did not differ in the percent change of rise time (5.09±49.13 vs 6.24±48.06; P = .93) and time to peak enhancement (8.82±54.5 vs 10.21±43.25; P = .3). Conclusion: Analysis of time-intensity curves obtained after injection of microbubble contrast material±weeks after beginning pharmacologic treatment can be used to differentiate responders from nonresponders among patients with clinically active Crohn disease
Predictors of intrahepatic cholangiocarcinoma in cirrhotic patients scanned by gadobenate dimeglumine-enhanced magnetic resonance imaging: Diagnostic accuracy and confidence
No full textObjective: To identify predictors of intrahepatic cholangiocarcinoma in cirrhotic patients scanned by gadobenate dimeglumine (Gd-BOPTA)-enhanced magnetic resonance (MR) imaging. Methods: Fifty cirrhotic patients with 120 nodules, including 10 mass-forming intrahepatic cholangiocarcinomas and two combined hepatocellular carcinoma-cholangiocarcinomas, were scanned by Gd-BOPTA-enhanced MR imaging. Results: T1 hypointensity [odds ratio (OR), 20.12], peripheral hyperintense rim at hepatic arterial phase (OR, 13.5), and iso-hyperintensity at hepatobiliary phase (OR 21.32) were found to be independent predictors of intrahepatic cholangiocarcinoma. Conclusions: T1 hypointensity, peripheral hyperintense rim at hepatic arterial phase, and iso-hyperintensity at hepatobiliary phase are independent predictors of intrahepatic cholangiocarcinoma diagnosis in patients with liver cirrhosis. © 2015 Elsevier Inc
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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