Vessel Axis Tracking Using Topology Constrained Surface Evolution

An approach to three-dimensional vessel axis tracking based on surface evolution is presented. The main idea is to guide the evolution of the surface by analyzing its skeleton topology during evolution, and imposing shape constraints on the topology. For example, the intermediate topology can be processed such that it represents a single vessel segment, a bifurcation, or a more complex vascular topology. The evolving surface is then re-initialized with the newly found topology. Re-initialization is a crucial step since it creates probing behavior of the evolving front, encourages the segmentation process to extract the vascular structure of interest and reduces the risk on leaking of the curve into the background. The method was evaluated in two computed tomography angiography applications: (i) extracting the internal carotid arteries including the region in which they traverse through the skull base, which is challenging due to the proximity of bone structures and overlap in intensity values, and (ii) extracting the carotid bifurcations including many cases in which they are severely stenosed and contain calcifications. The vessel axis was found in 90% (18/20 internal carotids in ten patients) and 70% (14/20 carotid bifurcations in a different set of ten patients) of the cases

Vessel enhancing diffusion: a scale space representation of vessel

A method is proposed to enhance vascular structures within the framework of scale space theory. We combine a smooth vessel filter which is based on a geometrical analysis of the Hessian's eigensystem, with a non-linear anisotropic diffusion scheme. The amount and orientation of diffusion depend on the local vessel likeliness. Vessel enhancing diffusion (VED) is applied to patient and phantom data and compared to linear, regularized Perona-Malik, edge and coherence enhancing diffusion. The method performs better than most of the existing techniques in visualizing vessels with varying radii and in enhancing vessel appearance. A diameter study on phantom data shows that VED least affects the accuracy of diameter measurements. It is shown that using VED as a preprocessing step improves level set based segmentation of the cerebral vasculature, in particular segmentation of the smaller vessels of the vasculature

Facing Forward, Nine stories about being a survivor of human trafficking in a post-trafficking shelter in the Netherlands

This report describes nine stories of six women and three men who recently exited a human trafficking situation and, at the time of this research, resided in a shelter for foreign victims of trafficking in the Netherlands. It speaks about their hopes and dreams, their fears and frustrations, and describes how they feel social and health care might be improved. The report’s aim is to shed more light on service users’ views on post-trafficking service provision for everyone directly (e.g. social workers, psychologists and general practitioners) and indirectly (e.g. managers and policymakers) involved with providing care to this group. The main message from the report is that victims of human trafficking in a post-trafficking shelter can be expected to exhibit a strong desire to move forward and establish a meaningful life with a job, a family and friends. This is an important conclusion: it shows that besides the ‘trauma’-narrative that is often stressed in the literature as being important among trafficking survivors, the ‘future‘-narrative is as important and should be taken into account in developing social and health services for this group. Despite the importance of being able to pursue a meaningful life to them, service users in this study were often stunted in doing just that. Through barriers in finding work, education and a place to live, often caused by their residency status, a feeling of being ostracized in Dutch society and shelter policies, service users often felt ‘in limbo’: standing still, without being able to change that situation. Regardless of this, and seemingly against all odds, service users still pursued their goals, by engaging in Dutch language courses, participating in vocational skills training and engaging in volunteer work. These activities were described as useful by participants and therefore preferable over other activities. Service users found them useful because they provided them with opportunities to work towards their envisioned futures. Hoping for the fulfilment of their goals and pursuing them in these ways likely allowed service users to better cope with their problems in the present and improved their well-being. For this reason, it is essential that social and health provision for this group supports and facilitates service users’ forwards-facing, future-orientated views, in addition to providing trauma-informed services. But do not take our word for it: please read the stories in this report and get to know these men and women, and read about what they, in their own words, feel service provision ought to look like in a post-trafficking shelter

Automatic nuclei segmentation in H&E stained breast cancer histopathology images

The introduction of fast digital slide scanners that provide whole slide images has led to a revival of interest in image analysis applications in pathology. Segmentation of cells and nuclei is an important first step towards automatic analysis of digitized microscopy images. We therefore developed an automated nuclei segmentation method that works with hematoxylin and eosin (H&E) stained breast cancer histopathology images, which represent regions of whole digital slides. The procedure can be divided into four main steps: 1) pre-processing with color unmixing and morphological operators, 2) marker-controlled watershed segmentation at multiple scales and with different markers, 3) post-processing for rejection of false regions and 4) merging of the results from multiple scales. The procedure was developed on a set of 21 breast cancer cases (subset A) and tested on a separate validation set of 18 cases (subset B). The evaluation was done in terms of both detection accuracy (sensitivity and positive predictive value) and segmentation accuracy (Dice coefficient). The mean estimated sensitivity for subset A was 0.875 (±0.092) and for subset B 0.853 (±0.077). The mean estimated positive predictive value was 0.904 (±0.075) and 0.886 (±0.069) for subsets A and B, respectively. For both subsets, the distribution of the Dice coefficients had a high peak around 0.9, with the vast majority of segmentations having values larger than 0.8. © 2013 Veta et al

Trade-off between angular and spatial resolutions in in vivo fiber tractography

Tractography is becoming an increasingly popular method to reconstruct white matter connections in vivo. The diffusion MRI data that tractography is based on requires a high angular resolution to resolve crossing fibers whereas high spatial resolution is required to distinguish kissing from crossing fibers. However, scan time increases with increasing spatial and angular resolutions, which can become infeasible in clinical settings. Here we investigated the trade-off between spatial and angular resolutions to determine which of these factors is most worth investing scan time in. We created a unique diffusion MRI dataset with 1.0mm isotropic resolution and a high angular resolution (100 directions) using an advanced 3D diffusion-weighted multi-slab EPI acquisition. This dataset was reconstructed to create subsets of lower angular (75, 50, and 25 directions) and lower spatial (1.5, 2.0, and 2.5mm) resolution. Using all subsets, we investigated the effects of angular and spatial resolutions in three fiber bundles-the corticospinal tract, arcuate fasciculus and corpus callosum-by analyzing the volumetric bundle overlap and anatomical correspondence between tracts. Our results indicate that the subsets of 25 and 50 directions provided inferior tract reconstructions compared with the datasets with 75 and 100 directions. Datasets with spatial resolutions of 1.0, 1.5, and 2.0mm were comparable, while the lowest resolution (2.5mm) datasets had discernible inferior quality. In conclusion, we found that angular resolution appeared to be more influential than spatial resolution in improving tractography results. Spatial resolutions higher than 2.0mm only appear to benefit multi-fiber tractography methods if this is not at the cost of decreased angular resolution

Aid alignment for global health research: the role of HIROs

The lack of a mechanism that aligns financial flows for global health research towards public health priorities limits the impact of health research on health and health equity. Collaborative groups of health research funders appear to be particularly well situated to ameliorate this situation and to initiate discussion on aid alignment for global health research. One such group is the Heads of International Research Organizations (HIROs), which brings together a large number of major government and philanthropic funders of biomedical research. Surprisingly, there is hardly any information publicly available on HIROs' objectives, or on how it aims to achieve more harmonization in the field of research for health. Greater transparency on HIROs' objectives and on its current efforts towards addressing the gap between global health research needs and investments would be desirable, given the enormous potential benefits of more coordination by this group

The impact generated by public and charity-funded research in the UK: A systematic literature review

Objective: To identify, synthesize and critically assess the empirical evidence of the impact generated by public and charity funded health research in the United Kingdom. Methods: We conducted a systematic literature review of the empirical evidence published in English in peer-reviewed journals between 2006 and 2017. Studies meeting the inclusion criteria were selected and their findings were analysed using the Payback Framework into five main categories: knowledge, benefits to future research and research use, benefits from informing policy and product development, health and health sector benefits and broader economic benefits. We assessed the studies for risk of selection, reporting and funding bias. Results: Thirteen studies met the inclusion criteria. The majority of the studies (10 out of 13) assessed impact at multiple domains including the main 5 key themes of the Payback Framework. All of them showed a positive impact of funded research on outcomes. Of those studies, one presented low risk of bias (8%), 6 studies were classified as presenting moderate risk of bias (46%) and 6 studies presented high risk of bias (46%). Conclusions: Empirical evidence on the impact of public and charity funded research is still limited and subject to funding and selection bias. More work is needed to establish the causal effects of funded research on academic outcomes, policy, practice and the broader economy