CFD and PIV analysis of hemodynamics in a growing intracranial aneurysm

Abstract

Hemodynamics is thought to be a fundamental factor in the formation, progression and rupture of cerebral aneurysms. Understanding these mechanisms is important to improve their rupture risk assessment and treatment. In this study we analyze the blood flow field in a growing cerebral aneurysm using experimental particle image velocimetry (PIV) and computational fluid dynamics (CFD) techniques. Patient-specific models were constructed from longitudinal 3D computed tomography angiography (CTA) images acquired at one-year intervals. Physical silicone models were constructed from the CTA images using rapid prototyping techniques and pulsatile flow fields were measured with PIV. Corresponding CFD models were created and run under matching flow conditions. Both flow fields were aligned, interpolated, and compared qualitatively by inspection and quantitatively by defining similarity measures between the PIV and CFD vector fields. Results showed that both flow fields were in good agreement. Specifically, both techniques provided consistent representations of the main intra-aneurysmal flow structures, and their change during the geometric evolution of the aneurysm. Despite differences observed mainly in the near wall region and the inherent limitations of each technique, the information derived is consistent and can be used to study the role of hemodynamics in the natural history of intracranial aneurysms.

Quantifying Intracranial Aneurysm Wall Permeability for Risk Assessment Using Dynamic Contrast-Enhanced MRI: A Pilot Study

“…The contrast agent permeability rate (K trans ) could then provide a surrogate measure of vessel wall integrity and focal degradation resulting from environmental factors such as hemodynamic stresses, typically assessed with advanced MR imaging acquisitions 8 and postprocessing algorithms. 9 The purpose of this work was to determine the feasibility of quantifying aneurysm wall permeability by using widely available dynamic contrast-enhanced (DCE)-MR imaging. Our goal was to develop an adjunctive imaging metric to complement existing anatomic and developing flow-based imaging markers of aneurysm risk (size, location, morphology, computational/4D flow dynamics).…”

Multi-time-lag PIV analysis of steady and pulsatile flows in a sidewall aneurysm

“…This value is in the lower range of those reported in Ugron et al (2012) and Raschi et al (2012). The former compared PIV measurements in IA models with the very precise laser doppler anemometry (Zhang 2010) (LDA) technique.…”

“…Though we used an idealized IA model, its size characteristics were in agreement with real sidewall ICA IAs (Morita et al 2012) i.e. without any rescaling factor commonly used to facilitate PIV measurements (Liou and Liao 1997;Yu and Zhao 1999;Tateshima et al 2003;Hoi et al 2006;Tateshima et al 2007;Liou et al 2007;Tateshima et al 2008;Morino et al 2010;Ugron et al 2012;Raschi et al 2012;Le et al 2013). This effort is necessary to investigate the hemodynamics effect of existing and future medical treatments (e.g.…”

“…During the last decade, several PIV measurements have been performed on IA models to evaluate, on one hand, the influence of different geometry parameters on flow dynamics (Liou and Liao 1997;Yu and Zhao 1999;Tateshima et al 2003Tateshima et al , 2007Tateshima et al , 2008Liou et al 2007;Ford et al 2008a;Yamaguchi et al 2008;Morino et al 2010;Tanoue et al 2011;Raschi et al 2012), and on the other hand, to validate computational fluid dynamics (CFD) predictions (Hoi et al 2006;Ford et al 2008b;Mulder et al 2009;Ugron et al 2012;Le et al 2013). Idealized IA models, made of a spherical aneurysm connected to a cylindrical pipe, were essentially used to study the influence of several factors: (a) the curvature of the parent artery (Liou and Liao 1997), (b) the angular orientation of IA with respect to parent vessel (in basilar tip (Ford et al 2008a) and sidewall IAs (Liou et al 2007)) and (c) IA aspect ratio (Yamaguchi et al 2008) (i.e.…”

“…ratio of aneurysm depth to neck width). Patient-specific geometries were used to evaluate the correlations with the clinical outcomes such as IA growth (Tateshima et al 2007;Tanoue et al 2011;Raschi et al 2012), IA rupture (Morino et al 2010), and the Electronic supplementary material The online version of this article (doi:10.1007/s00348-014-1746-0) contains supplementary material, which is available to authorized users. atherosclerotic changes in the aneurysm wall (Tateshima et al 2008).…”