Improving Fiber Alignment in HARDI by Combining Contextual PDE Flow with Constrained Spherical Deconvolution

We propose two strategies to improve the quality of tractography results computed from diffusion weighted magnetic resonance imaging (DW-MRI) data. Both methods are based on the same PDE framework, defined in the coupled space of positions and orientations, associated with a stochastic process describing the enhancement of elongated structures while preserving crossing structures. In the first method we use the enhancement PDE for contextual regularization of a fiber orientation distribution (FOD) that is obtained on individual voxels from high angular resolution diffusion imaging (HARDI) data via constrained spherical deconvolution (CSD). Thereby we improve the FOD as input for subsequent tractography. Secondly, we introduce the fiber to bundle coherence (FBC), a measure for quantification of fiber alignment. The FBC is computed from a tractography result using the same PDE framework and provides a criterion for removing the spurious fibers. We validate the proposed combination of CSD and enhancement on phantom data and on human data, acquired with different scanning protocols. On the phantom data we find that PDE enhancements improve both local metrics and global metrics of tractography results, compared to CSD without enhancements. On the human data we show that the enhancements allow for a better reconstruction of crossing fiber bundles and they reduce the variability of the tractography output with respect to the acquisition parameters. Finally, we show that both the enhancement of the FODs and the use of the FBC measure on the tractography improve the stability with respect to different stochastic realizations of probabilistic tractography. This is shown in a clinical application: the reconstruction of the optic radiation for epilepsy surgery planning

Onderzoek naar Duurzame Schelpdiervisserij (PRODUS) Eindrapport deelproject 1 c

De fluctuaties in aanbod van mosselzaad en druk op de visserij hebben er toe geleid dat de sector is gaan zoeken naar alternatieve bronnen van jonge mosselen. Sinds 2000 wordt gewerkt aan het ontwikkelen van mosselzaadinvangsystemen (MZI’s). Er is onder andere gekeken naar variatie in zaadinvang en groei van het zaad, het effect van MZI's op de bodemfauna en -structuur en op vogels en zeezoogdieren. Het artikel eindigt met enkele conclusies en aanbevelingen

A database for on-line event analysis on a distributed memory machine

Parallel in-memory databases can enhance the structuring and parallelization of programs used in High Energy Physics (HEP). Efficient database access routines are used as communication primitives which hide the communication topology in contrast to the more explicit communications like PVM or MPI. A parallel in-memory database, called SPIDER, has been implemented on a 32 node Meiko CS-2 distributed memory machine. The spider primitives generate a lower overhead than the one generated by PVM or PMI. The event reconstruction program, CPREAD of the CPLEAR experiment, has been used as a test case. Performance measurerate generated by CPLEAR

De veranderingen en groei van het Tweede Boek van het Wetboek van Strafrecht. Een historische analyse van zijn externe structuur in de periode 1886-2017

Recently a project was started that aims to systematically describe and explain the developments in the Criminal Code for the period 1886 - 2017. This article presents the first results of this new project, called the Historical Criminal Code (HWvSr). An overview is given of the long-term developments in the structure – the ‘external’ structure – of the Second Book of the Criminal Code since 1886. The analyzes show that its scope has been substantially expanded over the last 130 years, but also that various articles and article parts have been deleted. The article describes the most important changes in terms of both quantity and content. Criminal Justice: Legitimacy, accountability, and effectivit

The educational needs of people with systemic sclerosis: a cross-sectional study using the Dutch version of the Educational Needs Assessment Tool (D-ENAT)

© 2015, The Author(s). The Dutch Educational Needs Assessment Tool (D-ENAT) systematically assesses educational needs of patients with rheumatic diseases. The present study aims to describe the educational needs of Dutch patients with systemic sclerosis (SSc). The D-ENAT was sent to 155 SSc patients registered at the outpatient clinic of a university hospital. The D-ENAT consists of 39 items in seven domains. “Each domain has different number of items therefore we normalized each domain score: (domain score/maximum)×100) and expressed in percentage to enable comparisons between domains.” A total D-ENAT score (0–156) is calculated by summing all 39 items. In addition, age, disease duration, gender, educational level, present information need (yes/no) and information need (1–4; wanting to know nothing–everything) were recorded. Univariate regression analysis was used to examine factors associated with the D-ENAT scores. The response rate was 103 out of 155 (66%). The mean % of educational needs scores (0–100%; lowest–highest) were 49% for “D-ENAT total score,” 46% for “Managing pain,” 41% for “Movement,” 43% for “Feelings,” 59% for “Disease process,” 44% for “Treatments from health professionals,” 61% for “Self-help measures” and 51% for “Support systems.” No associations between the D-ENAT total score and age, disease duration, gender and educational level were found. The D-ENAT demonstrated its ability to identify educational needs of Dutch SSc patients. SSc patients demonstrated substantial educational needs, especially in the domains: “Disease process” and “Self-help measures.” The validity and practical applicability of the D-ENAT to make an inventory of SSc patients’ educational needs require further investigation

What Are the Interobserver and Intraobserver Variability of Gap and Stepoff Measurements in Acetabular Fractures?

BACKGROUND: Gap and stepoff values in the treatment of acetabular fractures are correlated with clinical outcomes. However, the interobserver and intraobserver variability of gap and stepoff measurements for all imaging modalities in the preoperative, intraoperative, and postoperative phase of treatment is unknown. Recently, a standardized CT-based measurement method was introduced, which provided the opportunity to assess the level of variability. QUESTIONS/PURPOSES: (1) In patients with acetabular fractures, what is the interobserver variability in the measurement of the fracture gaps and articular stepoffs determined by each observer to be the maximum one in the weightbearing dome, as measured on pre- and postoperative pelvic radiographs, intraoperative fluoroscopy, and pre- and postoperative CT scans? (2) What is the intraobserver variability in these measurements? METHODS: Sixty patients with a complete subset of pre-, intra- and postoperative high-quality images (CT slices of < 2 mm), representing a variety of fracture types with small and large gaps and/or stepoffs, were included. A total of 196 patients with nonoperative treatment (n = 117), inadequate available imaging (n = 60), skeletal immaturity (n = 16), bilateral fractures (n = 2) or a primary THA (n = 1) were excluded. The maximum gap and stepoff values in the weightbearing dome were digitally measured on pelvic radiographs and CT images by five independent observers. Observers were free to decide which gap and/or stepoff they considered the maximum and then measure these before and after surgery. The observers were two trauma surgeons with more than 5 years of experience in pelvic surgery, two trauma surgeons with less than 5 years of experience in pelvic surgery, and one surgical resident. Additionally, the final intraoperative fluoroscopy images were assessed for the presence of a gap or stepoff in the weightbearing dome. All observers used the same standardized measurement technique and each observer measured the first five patients together with the responsible researcher. For 10 randomly selected patients, all measurements were repeated by all observers, at least 2 weeks after the initial measurements. The intraclass correlation coefficient (ICC) for pelvic radiographs and CT images and the kappa value for intraoperative fluoroscopy measurements were calculated to determine the inter- and intraobserver variability. Interobserver variability was defined as the difference in the measurements between observers. Intraobserver variability was defined as the difference in repeated measurements by the same observer. RESULTS: Preoperatively, the interobserver ICC was 0.4 (gap and stepoff) on radiographs and 0.4 (gap) and 0.3 (stepoff) on CT images. The observers agreed on the indication for surgery in 40% (gap) and 30% (stepoff) on pelvic radiographs. For CT scans the observers agreed in 95% (gap) and 70% (stepoff) of images. Postoperatively, the interobserver ICC was 0.4 (gap) and 0.2 (stepoff) on radiographs. The observers agreed on whether the reduction was acceptable or not in 60% (gap) and 40% (stepoff). On CT images the ICC was 0.3 (gap) and 0.4 (stepoff). The observers agreed on whether the reduction was acceptable in 35% (gap) and 38% (stepoff). The preoperative intraobserver ICC was 0.6 (gap and stepoff) on pelvic radiographs and 0.4 (gap) and 0.6 (stepoff) for CT scans. Postoperatively, the intraobserver ICC was 0.7 (gap) and 0.1 (stepoff) on pelvic radiographs. On CT the intraobserver ICC was 0.5 (gap) and 0.3 (stepoff). There was no agreement between the observers on the presence of a gap or stepoff on intraoperative fluoroscopy images (kappa -0.1 to 0.2). CONCLUSIONS: We found an insufficient interobserver and intraobserver agreement on measuring gaps and stepoffs for supporting clinical decisions in acetabular fracture surgery. If observers cannot agree on the size of the gap and stepoff, it will be challenging to decide when to perform surgery and study the results of acetabular fracture surgery. LEVEL OF EVIDENCE: Level III, diagnostic study