Quantifying the Large-Scale Hemodynamics of Intracranial Aneurysms

BACKGROUND AND PURPOSE: Hemodynamics play an important role in the mechanisms that govern the initiation, growth, and possible rupture of intracranial aneurysms. The purpose of this study was to objectively characterize these dynamics, classify them, and connect them to aneurysm rupture. MATERIALS AND METHODS: Image-based computational fluid dynamic simulations were used to re-create the hemodynamics of 210 patient-specific intracranial aneurysm geometries. The hemodynamics were then classified according to their spatial complexity and temporal stability by using quantities derived from vortex core lines and proper orthogonal decomposition. RESULTS: The quantitative classification was compared with a previous qualitative classification performed by visual inspection. Receiver operating characteristic curves provided area-under-the-curve estimates for spatial complexity (0.905) and temporal stability (0.85) to show that the 2 classifications were in agreement. Statistically significant differences were observed in the quantities describing the hemodynamics of ruptured and unruptured intracranial aneurysms. Specifically, ruptured aneurysms had more complex and more unstable flow patterns than unruptured aneurysms. Spatial complexity was more strongly associated with rupture than temporal stability. CONCLUSIONS: Complex-unstable blood flow dynamics characterized by longer core line length and higher entropy could induce biologic processes that predispose an aneurysm for rupture.

[1]  L. Sirovich.  Turbulence and the dynamics of coherent structures. III. Dynamics and scaling , 1987 .

[2]  Alberto M. Gambaruto,et al.  Flow structures in cerebral aneurysms , 2012 .

[3]  MING JIANG,et al.  Detection and Visualization of Vortices , 2005, The Visualization Handbook.

[4]  C. Putman,et al.  Quantitative Characterization of the Hemodynamic Environment in Ruptured and Unruptured Brain Aneurysms , 2010, American Journal of Neuroradiology.

[5]  Charles Hansen,et al.  The Visualization Handbook , 2011 .

[6]  W. Koch,et al.  Biology of Intracranial Aneurysms: Role of Inflammation , 2012, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[7]  T. Christian Gasser,et al.  Blood flow and coherent vortices in the normal and aneurysmatic aortas: a fluid dynamical approach to intra-luminal thrombus formation , 2011, Journal of The Royal Society Interface.

[8]  Alejandro F. Frangi,et al.  Efficient pipeline for image-based patient-specific analysis of cerebral aneurysm hemodynamics: technique and sensitivity , 2005, IEEE Transactions on Medical Imaging.

[9]  D. Kallmes,et al.  The influence of hemodynamic forces on biomarkers in the walls of elastase-induced aneurysms in rabbits , 2007, Neuroradiology.

[10]  Ronald Peikert,et al.  Flow visualization for turbomachinery design , 1996, Proceedings of Seventh Annual IEEE Visualization '96.

[11]  S. Shadden,et al.  Characterization of the transport topology in patient-specific abdominal aortic aneurysm models. , 2012, Physics of fluids.

[12]  D. Sujudi,et al.  Identification of Swirling Flow in 3-D Vector Fields , 1995 .

[13]  Fernando Mut,et al.  CFD and PIV analysis of hemodynamics in a growing intracranial aneurysm , 2012, International journal for numerical methods in biomedical engineering.

[14]  W. Young,et al.  Intracranial aneurysms: links among inflammation, hemodynamics and vascular remodeling , 2006, Neurological research.

[15]  D. Holdsworth,et al.  Characterization of volumetric flow rate waveforms in the normal internal carotid and vertebral arteries , 2005, Physiological measurement.

[16]  L. Sirovich.  Turbulence and the dynamics of coherent structures. I. Coherent structures , 1987 .

[17]  C. Putman,et al.  Hemodynamics of Cerebral Aneurysms. , 2009, Annual review of fluid mechanics.

[18]  F. Mut,et al.  Association of Hemodynamic Characteristics and Cerebral Aneurysm Rupture , 2011, American Journal of Neuroradiology.

[19]  Jingfeng Jiang,et al.  Computational fluid dynamics simulations of intracranial aneurysms at varying heart rates: a "patient-specific" study. , 2009, Journal of biomechanical engineering.

[20]  Tatsuya Ishikawa,et al.  How does spontaneous hemostasis occur in ruptured cerebral aneurysms? Preliminary investigation on 247 clipping surgeries. , 2006, Surgical neurology.

[21]  Nadine Aubry,et al.  Spatiotemporal analysis of complex signals: Theory and applications , 1991 .

[22]  Ricardo J. Komotar,et al.  Hemodynamic mechanisms underlying cerebral aneurysm pathogenesis , 2011, Journal of Clinical Neuroscience.

[23]  Aki Laakso,et al.  Saccular intracranial aneurysm: pathology and mechanisms , 2012, Acta Neuropathologica.

[24]  M. Zweig,et al.  Receiver-operating characteristic (ROC) plots: a fundamental evaluation tool in clinical medicine. , 1993, Clinical chemistry.

[25]  B. R. Noack.  Turbulence, Coherent Structures, Dynamical Systems and Symmetry , 2013 .

[26]  Aichi Chien,et al.  Computational hemodynamics framework for the analysis of cerebral aneurysms , 2011, International journal for numerical methods in biomedical engineering.

[27]  C. Putman,et al.  Characterization of cerebral aneurysms for assessing risk of rupture by using patient-specific computational hemodynamics models. , 2005, AJNR. American journal of neuroradiology.