Virtual Intracranial Stenting Challenge 2011: Input data

<p>Input data provided to the participants of the Virtual Intracranial Stenting Challenge 2011 (VISC'11).</p> <p> </p> <p>Fileset content:</p> <p>* surface.stl: STL surface mesh (in mm) of vascular geometry</p> <p>* ccs*.stl, ocs*.stl: STL surface meshes (in mm) of deployed stent geometries </p> <p>* geometry.pdf: Image of vascular and stent geometries with labels for inlets/outlets and regions-of-interest</p> <p>* challenge_instructions.txt: Instructions to challenge participants, including flow rate boundary conditions and blood properties</p> <p> </p> <p>More details on VISC'11:</p> <p>Cito S, Geers AJ, Arroyo MP, Palero VR, Pallarés J, Vernet A, Blasco J, San Román L, Fu W, Qiao A, Janiga G, Miura Y, Ohta M, Mendina M, Usera G, Frangi AF. Accuracy and Reproducibility of Patient-Specific Hemodynamics Models of Stented Intracranial Aneurysms: Report on the Virtual Intracranial Stenting Challenge 2011. Annals of Biomedical Engineering, 43(1):154-167, 2015.</p> <p> </p> <p>Contact:</p> <p>Arjan Geers ([email protected])</p> <p> </p> <p>Links:</p> <p>* http://dx.doi.org/10.6084/m9.figshare.1060453 : FigShare fileset "VISC'11: Particle imaging velocimetry data"</p> <p>* http://dx.doi.org/10.6084/m9.figshare.1060464 : FigShare fileset "VISC'11: CFD solutions group E"</p> <p>* https://github.com/ajgeers/visc11 : GitHub repository with code to reproduce the plots of the journal paper</p

Virtual Intracranial Stenting Challenge 2011: Particle imaging velocimetry data

<p>Particle imaging velocimetry data belonging to the Virtual Intracranial Stenting Challenge 2011 (VISC'11). The dataset was used to validate CFD solutions provided by challenge participants. Specifically, the dataset was used to validate the in-plane velocity field on the xy-plane at z = 0 mm for the untreated case.</p> <p> </p> <p>Fileset content:</p> <p>* piv.vti: PIV dataset (in mm) stored in a vtkImageData object</p> <p> </p> <p>Notes:</p> <p>* The image region for x < -6 mm was excluded from data analysis for the journal paper. The normal of the glass surface was nearly perpendicular to the optical axis in this region and the PIV technique could not reliably estimate the velocity field. As mentioned in the paper, even after excluding part of the PIV image, relatively large differences between CFD and PIV were found near the lower bound of the x-axis.</p> <p>* The PIV image and vascular geometry were placed in the same coordinate system. They were positioned such that the xy-plane at z = 0 mm (corresponding to the PIV plane) approximately sliced the main flow jet into the aneurysm along its axis.</p> <p> </p> <p>More details on VISC'11:</p> <p>Cito S, Geers AJ, Arroyo MP, Palero VR, Pallarés J, Vernet A, Blasco J, San Román L, Fu W, Qiao A, Janiga G, Miura Y, Ohta M, Mendina M, Usera G, Frangi AF. Accuracy and Reproducibility of Patient-Specific Hemodynamics Models of Stented Intracranial Aneurysms: Report on the Virtual Intracranial Stenting Challenge 2011. Annals of Biomedical Engineering, 43(1):154-167, 2015.</p> <p> </p> <p>Contact:</p> <p>Arjan Geers ([email protected])</p> <p> </p> <p>Links:</p> <p>* http://dx.doi.org/10.6084/m9.figshare.1060443 : FigShare fileset "VISC'11: Input data"</p> <p>* http://dx.doi.org/10.6084/m9.figshare.1060464 : FigShare fileset "VISC'11: CFD solutions group E"</p> <p>* https://github.com/ajgeers/visc11 : GitHub repository with code to reproduce the plots of the journal paper</p

Core/Shell Nanocomposites Produced by Superfast Sequential Microfluidic Nanoprecipitation

Although a number of techniques exist for generating structured organic nanocomposites, it is still challenging to fabricate them in a controllable, yet universal and scalable manner. In this work, a microfluidic platform, exploiting superfast (milliseconds) time intervals between sequential nanoprecipitation processes, has been developed for high-throughput production of structured core/shell nanocomposites. The extremely short time interval between the sequential nanoprecipitation processes, facilitated by the multiplexed microfluidic design, allows us to solve the instability issues of nanocomposite cores without using any stabilizers. Beyond high throughput production rate (∼700 g/day on a single device), the generated core/shell nanocomposites harness the inherent ultrahigh drug loading degree and enhanced payload dissolution kinetics of drug nanocrystals and the controlled drug release from polymer-based nanoparticles

Real-world variability in the prediction of intracranial aneurysm wall shear stress: The 2015 International Aneurysm CFD Challenge

Purpose—Image-based computational fluid dynamics (CFD) is widely used to predict intracranial aneurysm wall shear stress (WSS), particularly with the goal of improving rupture risk assessment. Nevertheless, concern has been expressed over the variability of predicted WSS and inconsistent associations with rupture. Previous challenges, and studies from individual groups, have focused on individual aspects of the image-based CFD pipeline. The aim of this Challenge was to quantify the total variability of the whole pipeline. Methods—3D rotational angiography image volumes of five middle cerebral artery aneurysms were provided to participants, who were free to choose their segmentation methods, boundary conditions, and CFD solver and settings. Participants were asked to fill out a questionnaire about their solution strategies and experience with aneurysm CFD, and provide surface distributions of WSS magnitude, from which we objectively derived a variety of hemodynamic parameters. Results—A total of 28 datasets were submitted, from 26 teams with varying levels of self-assessed experience. Wide variability of segmentations, CFD model extents, and inflow rates resulted in interquartile ranges of sac average WSS up to 56%, which reduced to < 30% after normalizing by parent artery WSS. Sac-maximum WSS and low shear area were more variable, while rank-ordering of cases by low or high shear showed only modest consensus among teams. Experience was not a significant predictor of variability. Conclusions—Wide variability exists in the prediction of intracranial aneurysm WSS. While segmentation and CFD solver techniques may be difficult to standardize across groups, our findings suggest that some of the variability in image-based CFD could be reduced by establishing guidelines for model extents, inflow rates, and blood properties, and by encouraging the reporting of normalized hemodynamic parameters