4 research outputs found
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, PallareĢs J, Vernet A, Blasco J, San RomaĢn 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>Ā </p>
<p>Fileset content:</p>
<p>* piv.vti: PIV dataset (in mm) stored in a vtkImageData object</p>
<p>Ā </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>*Ā 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>Ā </p>
<p>More details on VISC'11:</p>
<p>Cito S, Geers AJ, Arroyo MP, Palero VR, PallareĢs J, Vernet A, Blasco J, San RomaĢn 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>Ā </p>
<p>Contact:</p>
<p>Arjan Geers ([email protected])</p>
<p>Ā </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 (ā¼700 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
PurposeāImage-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.
Methodsā3D 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.
ResultsāA 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.
ConclusionsāWide 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