142 research outputs found

    ISMRM Open Science Initiative for Perfusion Imaging (OSIPI): ASL pipeline inventory

    Get PDF
    Purpose: To create an inventory of image processing pipelines of arterial spin labeling (ASL) and list their main features, and to evaluate the capability, flexibility, and ease of use of publicly available pipelines to guide novice ASL users in selecting their optimal pipeline. Methods: Developers self-assessed their pipelines using a questionnaire developed by the Task Force 1.1 of the ISMRM Open Science Initiative for Perfusion Imaging. Additionally, each publicly available pipeline was evaluated by two independent testers with basic ASL experience using a scoring system created for this purpose. Results: The developers of 21 pipelines filled the questionnaire. Most pipelines are free for noncommercial use (n = 18) and work with the standard NIfTI (Neuroimaging Informatics Technology Initiative) data format (n = 15). All pipelines can process standard 3D single postlabeling delay pseudo-continuous ASL images and primarily differ in their support of advanced sequences and features. The publicly available pipelines (n = 9) were included in the independent testing, all of them being free for noncommercial use. The pipelines, in general, provided a trade-off between ease of use and flexibility for configuring advanced processing options. Conclusion: Although most ASL pipelines can process the common ASL data types, only some (namely, ASLPrep, ASLtbx, BASIL/Quantiphyse, ExploreASL, and MRICloud) are well-documented, publicly available, support multiple ASL types, have a user-friendly interface, and can provide a useful starting point for ASL processing. The choice of an optimal pipeline should be driven by specific data to be processed and user experience, and can be guided by the information provided in this ASL inventory

    Waist circumference and risk of elevated blood pressure in children: a cross-sectional study

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Increasing childhood obesity has become a major health threat. This cross-sectional study reports associations between schoolchildren's waist circumference (WC) and risk of elevated blood pressure.</p> <p>Methods</p> <p>We measured height, weight, neck and waist circumference, and blood pressure in regular health examinations among children in grade 1 (ages 6-7 years) at six elementary schools in Taipei County, Taiwan. Elevated blood pressure was defined in children found to have mean systolic or diastolic blood pressure greater than or equal to the gender-, age-, and height-percentile-specific 95th-percentile blood pressure value.</p> <p>Results</p> <p>All 2,334 schoolchildren were examined (response rate was 100% in the six schools). The mean of systolic and diastolic blood pressure increased as WC quartiles increased (p < 0.0001). The prevalence of elevated blood pressure for boys and girls within the fourth quartile of waist circumference was 38.9% and 26.8%, respectively. In the multivariate logistic regression analyses, the adjusted odds ratios of elevated blood pressure were 1.78 (95% confidence interval [CI] = 1.13-2.80), 2.45 (95% CI = 1.56-3.85), and 6.03 (95% CI = 3.59-10.1) for children in the second, third, and fourth waist circumference quartiles compared with the first quartile. The odds ratios for per-unit increase and per increase of standard deviation associated with elevated blood pressure were 1.14 (95% CI = 1.10-1.18) and 2.22 (95% CI = 1.76-2.78), respectively.</p> <p>Conclusions</p> <p>Elevated blood pressure in children was associated with waist circumference. Not only is waist circumference easier to measure than blood pressure, but it also provides important information on metabolic risk. Further research is needed on effective interventions to identify and monitor children with increased waist circumference to reduce metabolic and blood pressure risks.</p

    Synthesis of Zinc Phosphonated Poly(ethylene imine) and Its Fire-Retardant Effect in Low-Density Polyethylene

    Get PDF
    A novel oligomeric intumescent fire-retardant chelate, zinc phosphonated poly(ethylene imine) (Zn-PEIP), with a variable Zn2+ loading, was synthesized. The chemical structure of Zn-PEIP was confirmed by FTIR, 13C NMR, and 31P NMR spectroscopies. The thermal behavior and fire retardancy of low-density polyethylene (LDPE) containing 25 wt % Zn-PEIPs with different amounts of Zn2+ were investigated by thermogravimetric analysis (TGA), limiting oxygen index (LOI) measurements, and cone calorimetry. The TGA results showed that higher concentrations of Zn2+ improved the thermal stability and increased the residue yield of LDPE. However, the data from the LOI and cone calorimetry tests showed that there is an optimum concentration of Zn2+ for the best fire-retardancy performance of LDPE. This behavior is ascribed to the high cross-link density resulting from zinc bridges, preventing normal swelling of the intumescent system. The surface morphology of the char was characterized by digital photography and scanning electron microscopy (SEM). This confirmed the optimum intumescence and coherent and strong barrier layer formation at an intermediate Zn2+ loading

    Risk sharing arrangements for pharmaceuticals: potential considerations and recommendations for European payers

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>There has been an increase in 'risk sharing' schemes for pharmaceuticals between healthcare institutions and pharmaceutical companies in Europe in recent years as an additional approach to provide continued comprehensive and equitable healthcare. There is though confusion surrounding the terminology as well as concerns with existing schemes.</p> <p>Methods</p> <p>Aliterature review was undertaken to identify existing schemes supplemented with additional internal documents or web-based references known to the authors. This was combined with the extensive knowledge of health authority personnel from 14 different countries and locations involved with these schemes.</p> <p>Results and discussion</p> <p>A large number of 'risk sharing' schemes with pharmaceuticals are in existence incorporating both financial-based models and performance-based/outcomes-based models. In view of this, a new logical definition is proposed. This is "<it>risk sharing' schemes should be considered as agreements concluded by payers and pharmaceutical companies to diminish the impact on payers' budgets for new and existing schemes brought about by uncertainty and/or the need to work within finite budgets</it>". There are a number of concerns with existing schemes. These include potentially high administration costs, lack of transparency, conflicts of interest, and whether health authorities will end up funding an appreciable proportion of a new drug's development costs. In addition, there is a paucity of published evaluations of existing schemes with pharmaceuticals.</p> <p>Conclusion</p> <p>We believe there are only a limited number of situations where 'risk sharing' schemes should be considered as well as factors that should be considered by payers in advance of implementation. This includes their objective, appropriateness, the availability of competent staff to fully evaluate proposed schemes as well as access to IT support. This also includes whether systematic evaluations have been built into proposed schemes.</p
    corecore