Performance evaluation of the ECAT HRRT: An LSO-LYSO double layer high resolution, high sensitivity scanner

The ECAT high resolution research tomograph (HRRT) is a dedicated brain and small animal PET scanner, with design features that enable high image spatial resolution combined with high sensitivity. The HRRT is the first commercially available scanner that utilizes a double layer of LSO/LYSO crystals to achieve photon detection with depth-of-interaction information. In this study, the performance of the commercial LSO/LYSO HRRT was characterized, using the NEMA protocol as a guideline. Besides measurement of spatial resolution, energy resolution, sensitivity, scatter fraction, count rate performance, correction for attenuation and scatter, hot spot recovery and image quality, a clinical evaluation was performed by means of a HR+/HRRT human brain comparison study. Point source resolution varied across the field of view from approximately 2.3 to 3.2 mm (FWHM) in the transaxial direction and from 2.5 to 3.4 mm in the axial direction. Absolute line-source sensitivity ranged from 2.5 to 3.3% and the NEMA-2001 scatter fraction equalled 45%. Maximum NECR was 45 kcps and 148 kcps according to the NEMA-2001 and 1994 protocols, respectively. Attenuation and scatter correction led to a volume uniformity of 6.3% and a system uniformity of 3.1%. Reconstructed values deviated up to 15 and 8% in regions with high and low densities, respectively, which can possibly be assigned to inaccuracies in scatter estimation. Hot spot recovery ranged from 60 to 94% for spheres with diameters of 1 to 2.2 cm. A high quantitative agreement was met between HR+ and HRRT clinical data. In conclusion, the ECAT HRRT has excellent resolution and sensitivity properties, which is a crucial advantage in many research studies

Enabling interactive process analysis with process mining and visual analytics

In a typical healthcare setting, specific clinical care pathways can be defined by the hospitals. Process mining provides a way of analyzing the care pathways by analyzing the event data extracted from the hospital information systems. Process mining can be used to optimize the overall care pathway, and gain interesting insights into the actual execution of the process, as well as to compare the expectations versus the reality. In this paper, a generic novel tool called InterPretA, is introduced which builds upon pre-existing process mining and visual analytics techniques to enable the user to perform such process oriented analysis. InterPretA contains a set of options to provide high level conformance analysis of a process from different perspectives. Furthermore, InterPretA enables detailed investigative analysis by letting the user interactively analyze, visualize and explore the execution of the processes from the data perspective

זכרון אפרים - רבבות אפרים

Importance High-sensitivity cardiac troponin I testing is widely used to evaluate patients with suspected acute coronary syndrome. A cardiac troponin concentration of less than 5 ng/L identifies patients at presentation as low risk, but the optimal threshold is uncertain. Objective To evaluate the performance of a cardiac troponin I threshold of 5 ng/L at presentation as a risk stratification tool in patients with suspected acute coronary syndrome. Data Sources Systematic search of MEDLINE, EMBASE, Cochrane, and Web of Science databases from January 1, 2006, to March 18, 2017. Study Selection Prospective studies measuring high-sensitivity cardiac troponin I concentrations in patients with suspected acute coronary syndrome in which the diagnosis was adjudicated according to the universal definition of myocardial infarction. Data Extraction and Synthesis The systematic review identified 19 cohorts. Individual patient-level data were obtained from the corresponding authors of 17 cohorts, with aggregate data from 2 cohorts. Meta-estimates for primary and secondary outcomes were derived using a binomial-normal random-effects model. Main Outcomes and Measures The primary outcome was myocardial infarction or cardiac death at 30 days. Performance was evaluated in subgroups and across a range of troponin concentrations (2-16 ng/L) using individual patient data. Results Of 11 845 articles identified, 104 underwent full-text review, and 19 cohorts from 9 countries were included. Among 22 457 patients included in the meta-analysis (mean age, 62 [SD, 15.5] years; n = 9329 women [41.5%]), the primary outcome occurred in 2786 (12.4%). Cardiac troponin I concentrations were less than 5 ng/L at presentation in 11 012 patients (49%), in whom there were 60 missed index or 30-day events (59 index myocardial infarctions, 1 myocardial infarction at 30 days, and no cardiac deaths at 30 days). This resulted in a negative predictive value of 99.5% (95% CI, 99.3%-99.6%) for the primary outcome. There were no cardiac deaths at 30 days and 7 (0.1%) at 1 year, with a negative predictive value of 99.9% (95% CI, 99.7%-99.9%) for cardiac death. Conclusions and Relevance Among patients with suspected acute coronary syndrome, a high-sensitivity cardiac troponin I concentration of less than 5 ng/L identified those at low risk of myocardial infarction or cardiac death within 30 days. Further research is needed to understand the clinical utility and cost-effectiveness of this approach to risk stratification

Reflective Practices for Future Journalism: The Need, the Resistance and the Way Forward

In newsrooms journalists encounter numerous constraints accelerated by increasing technological and economic pressures. The complexity of the job and the need for (constant) innovation coupled with the rising call for transparency and accountability ask for journalists who "reflect-in-action". Newsroom ethnographies consistently suggest that journalists experience a gap between the wish for increased self-reflection and its actual practice. Additionally, both newsroom research and journalists’ expressions in the trade press show significant resistance against reflection as being a largely academic exercise, or simply too time-consuming. We propose that considering reflection primarily from a learning perspective can overcome this resistance. Secondly, the article acknowledges that in order to enable professionals to fit reflection into their precarious practice, critical reflection should develop out of the practice itself. Reflection only makes sense if it starts from the sense of immediacy and autonomy within journalistic practice, recognises the constraints that journalists face and acknowledges the aversion among journalists against standardised protocols in their craft. Outlining the basic tenets of reflective practice, journalism's current precarity and the learning perspective, we propose further research in how informal reflective practices can enhance professional autonomy

The evolution of a media image: Newspaper attention to the Flemish far right 1987-2004

Contains fulltext : 102995.pdf (publisher's version ) (Closed access)This article investigates changes in attention to the far right in Flemish newspapers. Not only the volume of attention will be analysed but especially how newspapers pay attention to the far right, focusing on the portrayal of far-right actors (substantial attention), and on favourable and unfavourable attributions of third parties in the news texts (support attention). For the content analysis, 2356 articles from three newspapers are investigated. The Flemish far right (Vlaams Blok) is unique because of its uninterrupted electoral growth between 1987 and 2004. Flemish newspapers still portray the far right as a controversial outsider. Such an image is constructed in the 1980s by focusing on a limited set of controversial characteristics of the far right. Even though the far right became the largest Flemish opposition party in the Belgian parliament and although media attention became more nuanced over the years, this media image was not replaced with another media image: the controversial outsider image remained dominant in the coverage between 1987 and 2004.22 p