Computational Fluid Dynamics and Cerebral Aneurysms

Abstract

Advances in computational techniques mitigated by faster computer hardware and improvements in software algorithms have increased interest in exploring their potential value for application in clinical research. Information derived from medical image data can be utilized to create computational models for simulating hemodynamics in cerebral aneurysms. In this chapter, we review the principles of computational fluid dynamics (CFD) aimed at this application and discuss results from selected studies which focused on developing CFD techniques for applications in clinical research. Validation studies comparing measurements with simulation results have demonstrated that this approach is viable and thereby encourage further development and refinement. They have also shown that multidisciplinary collaborative teams involving clinicians and clinical and basic scientists are needed to lead these exciting translational research efforts to fruition. Glossary of Terms AneurysmA focal balloon-like extension or bulge in a blood vessel. Cerebral aneurysms affect arteries of the brain, while aortic aneurysms are located in the aorta. Computational fluid dynamicsA subspecialty of the large field of fluid mechanics in which numerical algorithms are developed and used with high-performance computers to solve problems related to fluid flow. Computed tomography angiographyA medical imaging technology where the computational analysis of X-rays is combined with the administration of a contrast agent to create three-dimensional visualization of blood vessels and the heart. Digital subtraction angiography A medical imaging technique based on fluoroscopy, where images acquired before and after the administration of a contrast agent are subtracted to obtain very accurate visualizations of blood vessels with high spatial resolution. Endothelium A thin layer of cells lining the inner surface of blood vessels. Endothelial cells have been shown to have receptors for sensing the wall shear stress created by the flowing blood. Endovascular treatmentA surgical technique to treat selected vascular pathologies in the brain and other parts of the body through a catheter and attached medical devices which are navigated to the treatment site within the blood vessels.*Email: ckarmonik@tmhs.org *Email: ckarmonik@houstonmethodist.org PanVascular Medicine DOI 10.1007/978-3-642-37393-0_33-1 # Springer-Verlag Berlin Heidelberg 2014Page 1 of 13 HemodynamicsThe field which aims at developing a better understanding of how blood flows in blood vessels by establishing the corresponding physical laws and the governing equations of motion. Magnetic resonance imagingA medical imaging technology which uses strong magnetic fields and radio-frequency pulses to probe and visualize anatomy and physiology both in health and disease. Mesh generationThe digital separation of an often irregularly shaped volume into small regular volume elements, for instance, tetrahedra, pyramids, or hexahedra. This is a prerequisite for applying computational simulations which rely ...

Depiction of Cerebral Aneurysm Wall by Computational Fluid Dynamics (CFD) and Preoperative Illustration

“…Other imaging modalities to generate CFD data include two-dimensional phase contrast magnetic resonance imaging (pcMRI) and 4D MRI. 6 7 Time-averaged WSS is used to predict the wall degradation and remodelling. 7 8 WSS “vector,” is used to indicate the viscous force vector per unit area of the aneurysm wall.…”

CFD and MRI studies of hemodynamic changes after flow diverter implantation in a patient-specific model of the cerebral artery

“…However, of particular interest for physicians are methods which allow evaluating the intra-aneurysmal flow in vivo. One of such methods is magnetic resonance imaging (MRI), which is a promising non-invasive method for analyzing intracranial hemodynamics (Papaharilaou et al 2001;Isoda et al 2006;Naito et al 2012;Muir et al 2014;Berg et al 2014;Karmonik et al 2014;Kono and Terada 2014). Several groups have used MRI velocity measurements to estimate directly the hemodynamic characteristics in the aneurysm region.…”

Building user interactive capabilities for image-based modeling of patient-specific biological flows in single platform

“…We obtained the CTA image of the vessel with saccular or sideways aneurysm. A saccular aneurysm is bulge in vessel where the ostium of the bulge is entirely contained in a part of the circumference of the wall of the vessel (P. C. Karmonik and Britz 2014). We noted that the maximum diameter, height of this aneurysm are small and its neck is broad when compared to the parent vessel indicating that the parameters like bottleneck factor and aspect ratio of the aneurysm are small and thus the vessel should not rupture (Hoh et al 2007).…”