Arterial spin labeling (ASL) has undergone significant development since its inception, with a focus on improving standardization and reproducibility of its acquisition and quantification. In a... Show moreArterial spin labeling (ASL) has undergone significant development since its inception, with a focus on improving standardization and reproducibility of its acquisition and quantification. In a community-wide effort towards robust and reproducible clinical ASL image processing, we developed the software package ExploreASL, allowing standardized analyses across centers and scanners.The procedures used in ExploreASL capitalize on published image processing advancements and address the challenges of multi-center datasets with scanner-specific processing and artifact reduction to limit patient exclusion. ExploreASL is self-contained, written in MATLAB and based on Statistical Parameter Mapping (SPM) and runs on multiple operating systems. To facilitate collaboration and data-exchange, the toolbox follows several standards and recommendations for data structure, provenance, and best analysis practice.ExploreASL was iteratively refined and tested in the analysis of >10,000 ASL scans using different pulse-sequences in a variety of clinical populations, resulting in four processing modules: Import, Structural, ASL, and Population that perform tasks, respectively, for data curation, structural and ASL image processing and quality control, and finally preparing the results for statistical analyses on both single-subject and group level. We illustrate ExploreASL processing results from three cohorts: perinatally HIV-infected children, healthy adults, and elderly at risk for neurodegenerative disease. We show the reproducibility for each cohort when processed at different centers with different operating systems and MATLAB versions, and its effects on the quantification of gray matter cerebral blood flow.ExploreASL facilitates the standardization of image processing and quality control, allowing the pooling of cohorts which may increase statistical power and discover between-group perfusion differences. Ultimately, this workflow may advance ASL for wider adoption in clinical studies, trials, and practice. Show less
According to theories of interpersonal distance people choose to position themselves in relation to nearby others in a way that optimizes intimacy and privacy. In two studies we investigated the... Show moreAccording to theories of interpersonal distance people choose to position themselves in relation to nearby others in a way that optimizes intimacy and privacy. In two studies we investigated the influence of intimacy and privacy on seating behavior in a café (coffee house) setting. In Study 1 (N = 71) we manipulated two aspects of intimacy (eye contact and distance to others), and one aspect of privacy (architectural anchoring) in separate scenario’s and registered participants’ seat choice on floor plans of the three hypothetical cafés. We found that more often participants chose a seat that was at a larger distance to other café-goers. Study 2 (N = 121) replicated the design of the first study, but included affective and cognitive appraisal measures concerning both available seats in each scenario. This time we found that participants more often chose low-eye contact and anchored seats. Choices in line with hypotheses as well as those that were against hypotheses co-occurred with strong beliefs about the pleasure and arousal that each choice might provide and related to the expectations of interaction with others present. Results qualify expectations about protection and violation of intimacy and privacy, at least for café settings. Show less
Sande, J. van de; Kriek, M.; Franx, M.; Dokkum, P.; Bezanson, R.; Whitaker, K.; ... ; Kaper, L. 2011
