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Computational and Mathematical Methods in Medicine
Volume 2016 (2016), Article ID 2386031, 12 pages
http://dx.doi.org/10.1155/2016/2386031
Research Article

Computational Hemodynamic Analysis for the Diagnosis of Atherosclerotic Changes in Intracranial Aneurysms: A Proof-of-Concept Study Using 3 Cases Harboring Atherosclerotic and Nonatherosclerotic Aneurysms Simultaneously

1Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Japan
2Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
3Department of Neuroanesthesia, Kohnan Hospital, Sendai, Japan
4Department of Neurosurgery, Kohnan Hospital, Sendai, Japan
5Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
6Institute of Fluid Science, Tohoku University, Sendai, Japan

Received 6 May 2016; Accepted 4 August 2016

Academic Editor: Enrique Berjano

Copyright © 2016 Shin-ichiro Sugiyama et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This was a proof-of-concept computational fluid dynamics (CFD) study designed to identify atherosclerotic changes in intracranial aneurysms. We selected 3 patients with multiple unruptured aneurysms including at least one with atherosclerotic changes and investigated whether an image-based CFD study could provide useful information for discriminating the atherosclerotic aneurysms. Patient-specific geometries were constructed from three-dimensional data obtained using rotational angiography. Transient simulations were conducted under patient-specific inlet flow rates measured by phase-contrast magnetic resonance velocimetry. In the postanalyses, we calculated time-averaged wall shear stress (WSS), oscillatory shear index, and relative residence time (RRT). The volume of blood flow entering aneurysms through the neck and the mean velocity of blood flow inside aneurysms were examined. We applied the age-of-fluid method to quantitatively assess the residence of blood inside aneurysms. Atherosclerotic changes coincided with regions exposed to disturbed blood flow, as indicated by low WSS and long RRT. Blood entered aneurysms in phase with inlet flow rates. The mean velocities of blood inside atherosclerotic aneurysms were lower than those inside nonatherosclerotic aneurysms. Blood in atherosclerotic aneurysms was older than that in nonatherosclerotic aneurysms, especially near the wall. This proof-of-concept study demonstrated that CFD analysis provided detailed information on the exchange and residence of blood that is useful for the diagnosis of atherosclerotic changes in intracranial aneurysms.