Morphology and Hemodynamics of Cerebral Arteries and Aneurysms in a Rare Pair of Monozygotic Twins.

In this preliminary study, the underlying pathophysiology mechanisms of cerebral aneurysms (CAs) in monozygotic twins (MTs) were investigated via a rare pair of MTs (twin A and twin B) involving four reconstructed arterial models using preclinical information. First, dimensions and configurated outlines of three-perspective geometries were compared. Adopting an in-vitro validated numerical CA model, hemodynamic characteristics were investigated in the MTs, respectively.

Numerical studies of hemodynamic alterations in pre- and post-stenting cerebral aneurysms using a multiscale modeling.

The aim of this work was to use a multiscale modeling to study the influence of stent deployment, with generic stents, on flow distributions within the vascular network and the hemodynamic alterations within the cerebral aneurysms pre- and post-stenting. To achieve this goal, two image-based anatomical cerebral aneurysm models were reconstructed along with the respective aneurysms post-stenting models after deploying a 16- or 24-wire stent. The investigation results revealed that the stent may increase the local pressure resistance resulting in flow alterations.

An In-Vitro Flow Study Using an Artificial Circle of Willis Model for Validation of an Existing One-Dimensional Numerical Model.

A one-dimensional (1D) numerical model has been previously developed to investigate the hemodynamics of blood flow in the entire human vascular network. In the current work, an experimental study of water-glycerin mixture flow in a 3D-printed silicone model of an anatomically accurate, complete circle of Willis (CoW) was conducted to investigate the flow characteristics in comparison with the simulated results by the 1D numerical model. In the experiment, the transient flow and pressure waveforms were measured at 13 selected segments within the flow network for comparisons.

A multiscale computational modeling for cerebral blood flow with aneurysms and/or stenoses.

A 1-dimensional (1D)-3-dimensional (3D) multiscale model for the human vascular network was proposed by combining a low-fidelity 1D modeling of blood circulation to account for the global hemodynamics with a detailed 3D simulation of a zonal vascular segment. The coupling approach involves a direct exchange of flow and pressure information at interfaces between the 1D and 3D models and thus enables patient-specific morphological models to be inserted into flow network with minimum computational efforts. The proposed method was validated with good agreements against 3 simplified test cases where experimental data and/or full 3D numerical solution were available.

The types of neurological deficits might not justify withholding treatment in patients with low total National Institutes of Health Stroke Scale scores.

Background And Purpose: There is controversy regarding the threshold for treating patients with mild strokes. Physicians often withhold acute treatment in these patients if they perceive the symptoms are not going to be disabling. We tested the appropriateness of this practice by analyzing the relationship between specific neurological deficits in the National Institutes of Health Stroke Scale (NIHSS) score and long-term outcome among patients with a low total NIHSS score.

Lack of international consensus on ethical aspects of acute stroke trials.

Acute stroke trials are becoming increasingly multinational. Working toward a shared ethical standard for acute stroke research necessitates evaluating the degree of consensus among international researchers. We surveyed all 275 coinvestigators and coordinators who participated in the AbESTT II study (evaluating abciximab vs placebo) about their experience with their local institutional review board (IRB) or equivalent, as well as, about their personal beliefs regarding the ethical aspects of acute stroke trials.