Imaging in axial spondyloarthritis

De belangrijkste resultaten van dit proefschrift: de ASAS classificatie criteria voor axSpA blijken robuust en zijn goed toepasbaar in een setting waarbij de waarschijnlijkheid op axSpA lager is dan waarin de criteria ontwikkeld zijn. Daarnaast is er op basis van bevindingen in dit proefschrift een belangrijke aanpassing doorgevoerd in een hulpmiddel dat reumatologen begeleidt in het diagnostische proces van (vroege) axSpA. Tevens is het MRI protocol van het SPACE cohort aangepast nadat de toegevoegde waarde van het toedienen van een contrastvloeistof bij het maken van MRI’s nihil bleek te zijn, met als resultaat dat er sinds april 2012 geen MRI’s meer worden gemaakt met de toediening van gadolinium. Dit proefschrift biedt ook adequate handvatten voor verder onderzoek naar de optimale definitie van een positieve MRI. Bovendien worden discrepanties aangaande de beoordeling door verschillende soorten lezers van afwijkingen in de rug (op röntgenfoto’s en MRI’s) aan het licht gebracht waardoor de vraag naar voren komt of training in het onderscheiden van axSpA afwijkingen en afwijkingen die niet gerelateerd zijn aan axSpA van potentiële belang is op de betrouwbaarheid van het beoordelen van afwijkingen in de rug. De onderzoeken in dit proefschrift leveren een bijdrage aan betere herkenning en behandeling van axSpA.PfizerLUMC / Geneeskund

Advertising-induced Embarrassment

Consumer embarrassment is an important concern for marketers. Yet, little is known about embarrassment in passive situations like advertising viewing. The authors investigate when and why consumers experience embarrassment as a result of exposure to socially sensitive advertisements. The theory distinguishes between viewing potentially embarrassing ads together with an audience that shares the social identity targeted by the message and viewing the same ads together with an audience that does not share the targeted social identity. Four studies provide support for the theory, demonstrating that advertising targeting and social context jointly determine feelings of embarrassment and advertising effectiveness

My style, my food, my waste! Consumer food waste-related lifestyle segments

Adapting responsible food marketing practices to different customer types can make a valuable contribution to reducing food waste. The current study investigated the relation between food (waste)-related lifestyle patterns and self-reported food waste, choices for suboptimal food, and food waste awareness using a survey with 4214 consumers across five Northern and Western European countries. Results show differences in food wastage, suboptimal choices, and awareness for five clusters of consumers identified on the basis of food (waste)-related lifestyle patterns. Findings of commonalities allow deriving general food marketing actions targeted to these different consumer lifestyles.submittedVersio

A priori model independent inverse potential mapping: the impact of electrode positioning

__Introduction:__ In inverse potential mapping, local epicardial potentials are computed from recorded body surface potentials (BSP). When BSP are recorded with only a limited number of electrodes, in general biophysical a priori models are applied to facilitate the inverse computation. This study investigated the possibility of deriving epicardial potential information using only 62 torso electrodes in the absence of an a priori model. __Methods:__ Computer simulations were used to determine the optimal in vivo positioning of 62 torso electrodes. Subsequently, three different electrode configurations, i.e., surrounding the thorax, concentrated precordial (30 mm inter-electrode distance) and super-concentrated precordial (20 mm inter-electrode distance) were used to record BSP from three healthy volunteers. Magnetic resonance imaging (MRI) was performed to register the electrode positions with respect to the anatomy of the patient. Epicardial potentials were inversely computed from the recorded BSP. In order to determine the reconstruction quality, the super-concentrated electrode configuration was applied in four patients with an implanted MRI-conditional pacemaker system. The distance between the position of the ventricular lead tip on MRI and the inversely reconstructed pacing site was determined. __Results:__ The epicardial potential distribution reconstructed using the super-concentrated electrode configuration demonstrated the highest correlation (R = 0.98; p < 0.01) with the original epicardial source model. A mean localization error of 5.3 mm was found in the pacemaker patients. __Conclusion:__ This study demonstrated the feasibility of deriving detailed anterior epicardial potential information using only 62 torso electrodes without the use of an a priori model

Integrated whole-heart computational workflow for inverse potential mapping and personalized simulations

Background: Integration of whole-heart activation simulations and inverse potential mapping (IPM) could benefit the guidance and planning of electrophysiological procedures. Routine clinical application requires a fast and adaptable workflow. These requirements limit clinical translation of existing simulation models. This study proposes a comprehensive finite element model (FEM) based whole-heart computational workflow suitable for IPM and simulations. Methods: Three volunteers and eight patients with premature ventricular contractions underwent body surface potential (BSP) acquisition followed by a cardiac MRI (CMR) scan. The cardiac volumes were segmented from the CMR images using custom written software. The feasibility to integrate tissue-characteristics was assessed by generating meshes with virtual edema and scar. Isochronal activation maps were constructed by identifying the fastest route through the cardiac volume using the Möller-Trumbore and Floyd-Warshall algorithms. IPM's were reconstructed from the BSP's. Results: Whole-heart computational meshes were generated within seconds. The first point of atrial activation on IPM was located near the crista terminalis of the superior vena cave into the right atrium. The IPM demonstrated the ventricular epicardial breakthrough at the attachment of the moderator band with the right ventricular free wall. Simulations of sinus rhythm were successfully performed. The conduction through the virtual edema and scar meshes demonstrated delayed activation or a complete conductional block respectively. Conclusion: The proposed FEM based whole-heart computational workflow offers an integrated platform for cardiac electrical assessment using simulations and IPM. This workflow can incorporate patient-specific electrical parameters, perform whole-heart cardiac activation simulations and accurately reconstruct cardiac activation sequences from BSP's