STUDY ON CEREBRAL ANEURYSMS: RUPTURE RISK PREDICTION USING GEOMETRICAL PARAMETERS AND WALL SHEAR STRESS WITH CFD AND MACHINE LEARNING TOOLS

Morphological characterization and fluid dynamics simulations were carried out to classify the rupture status of 71 (36 unruptured, 35 ruptured) patient specific cerebral aneurysms using a machine learning approach together with statistical techniques. Eleven morphological and six hemodynamic parameters were evaluated individually and collectively for significance as rupture status predictors. The performance of each parameter was inspected using hypothesis testing, accuracy, confusion matrix, and the area under the receiver operating characteristic curve. Overall, the size ratio exhibited the best performance, followed by the diastolic wall shear stress, and systolic wall shear stress. The prediction capability of all 17 parameters together was evaluated using eight different machine learning algorithms. The logistic regression achieved the highest accuracy (0.75), whereas the random forest had the highest area under curve value among all the classifiers (0.82), surpassing the performance exhibited by the size ratio. Hence, we propose the random forest model as a tool that can help improve the rupture status prediction of cerebral aneurysms.

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Hemodynamics Modeling and Simulation of Anterior Communicating Artery Aneurysms

Advances in Mechanical Engineering ◽

10.1155/2014/908357 ◽

2014 ◽

Vol 6 ◽

pp. 908357 ◽

Cited By ~ 1

Author(s):

Jianjun Li ◽

Shengzhang Wang ◽

Gang Lu ◽

Xiaolong Zhang

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Cerebral Aneurysms ◽

Artery Aneurysm ◽

Oscillatory Shear ◽

Anterior Communicating Artery ◽

Rupture Risk ◽

Oscillatory Shear Index ◽

Anterior Communicating Artery Aneurysms ◽

Wall Shear

It is a general agreement that hemodynamics plays very important role in the initiation, growth, and rupture of cerebral aneurysms and hemodynamics in the anterior communicating artery aneurysms is considered the most complex in all cerebral aneurysms and it is difficult to find some reasonable relationship between the hemodynamics parameters and the rupture risk. In this paper, the 3D geometries of four anterior communicating artery aneurysms were generated from the CTA data and the computational models with bilateral feeding arteries for the four aneurysms were constructed. The blood flow was simulated by computational fluid dynamics software and the hemodynamics parameters such as velocity, wall shear stress, and oscillatory shear index were calculated. The following results were observed: one of the four models only needs the left feeding artery; the max normalized wall shear stress locates at the aneurysmal neck of the largest aneurysm; the max oscillatory shear index locates at the aneurysmal sac of the largest aneurysm. The conclusion was drawn that the anterior communicating artery aneurysm has higher rupture risk from the hemodynamics viewpoint if the max wall shear stress locates at the neck and the max oscillatory shear index locates at the dome.

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Role of pressure and wall shear stress in initiation and development of cerebral aneurysms

2011 2nd International Conference on Instrumentation, Communications, Information Technology, and Biomedical Engineering ◽

10.1109/icici-bme.2011.6108629 ◽

2011 ◽

Cited By ~ 2

Author(s):

Nedya Utami ◽

Hasballah Zakaria ◽

Tati L. R. Mengko ◽

Oerip S. Santoso

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Cerebral Aneurysms ◽

Wall Shear

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Exploring High Frequency Temporal Fluctuations in the Terminal Aneurysm of the Basilar Bifurcation

Journal of Biomechanical Engineering ◽

10.1115/1.4007279 ◽

2012 ◽

Vol 134 (9) ◽

Cited By ~ 15

Author(s):

Matthew D. Ford ◽

Ugo Piomelli

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

High Frequency ◽

Cerebral Aneurysms ◽

Patient Specific ◽

Disturbed Flow ◽

Frequency Fluctuations ◽

Wall Shear ◽

Inflow Jet

Cerebral aneurysms are a common cause of death and disability. Of all the cardiovascular diseases, aneurysms are perhaps the most strongly linked with the local fluid mechanic environment. Aside from early in vivo clinical work that hinted at the possibility of high-frequency intra-aneurysmal velocity oscillations, flow in cerebral aneurysms is most often assumed to be laminar. This work investigates, through the use of numerical simulations, the potential for disturbed flow to exist in the terminal aneurysm of the basilar bifurcation. The nature of the disturbed flow is explored using a series of four idealized basilar tip models, and the results supported by four patient specific terminal basilar tip aneurysms. All four idealized models demonstrated instability in the inflow jet through high frequency fluctuations in the velocity and the pressure at approximately 120 Hz. The instability arises through a breakdown of the inflow jet, which begins to oscillate upon entering the aneurysm. The wall shear stress undergoes similar high-frequency oscillations in both magnitude and direction. The neck and dome regions of the aneurysm present 180 deg changes in the direction of the wall shear stress, due to the formation of small recirculation zones near the shear layer of the jet (at the frequency of the inflow jet oscillation) and the oscillation of the impingement zone on the dome of the aneurysm, respectively. Similar results were observed in the patient-specific models, which showed high frequency fluctuations at approximately 112 Hz in two of the four models and oscillations in the magnitude and direction of the wall shear stress. These results demonstrate that there is potential for disturbed laminar unsteady flow in the terminal aneurysm of the basilar bifurcation. The instabilities appear similar to the first instability mode of a free round jet.

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Wall shear stress at the initiation site of cerebral aneurysms

Biomechanics and Modeling in Mechanobiology ◽

10.1007/s10237-016-0804-3 ◽

2016 ◽

Vol 16 (1) ◽

pp. 97-115 ◽

Cited By ~ 12

Author(s):

A. J. Geers ◽

H. G. Morales ◽

I. Larrabide ◽

C. Butakoff ◽

P. Bijlenga ◽

...

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Cerebral Aneurysms ◽

Initiation Site ◽

Wall Shear

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Analysis of Flow and Wall Shear Stress in Curvature Induced Dorsal Aneurysms: Effect of Arterial Curvature

Volume 2: Biomedical and Biotechnology Engineering ◽

10.1115/imece2009-11322 ◽

2009 ◽

Author(s):

Arun Ramu ◽

Guo-Xiang Wang

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Fluid Dynamic ◽

Cerebral Arteries ◽

Cerebral Aneurysms ◽

Morbidity Rate ◽

Mortality And Morbidity ◽

Wall Shear ◽

Primary Velocity ◽

The Impact

Intracranial aneurysms are abnormal enlargement in the walls of cerebral arteries. The rupture of aneurysms is the leading cause of subarachnoid hemorrhage (SAH), with a high mortality and morbidity rate. A majority of saccular cerebral aneurysms occur at sites of arterial bifurcations. However, a good percentage of aneurysms are curvature induced and are found along the cavernous arterial segment. The occurrence of such non branching aneurysms, clinically called dorsal aneurysms, can be related to the increased wall shear stress at the curved arteries. The rupture of aneurysms usually occurs at the dome region, which is subjected to reduced wall shear stress (wss) owing to low re-circulating flow. Hence it is important to understand the impact of arterial curvature on the WSS distribution along the dome of aneurysms. Previously, studies have not taken into account the aspect of low WSS along the dome region. In the present 3-d computational fluid dynamic approach, we investigate the impact of varying arterial curvature on spherical dorsal aneurysms. The primary velocity patterns, the WSS distribution along the dome of the aneurysm and the area of increased WSS have been quantified for steady flow conditions.

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Differential Gene Expression of Endothelial Cells Under High Wall Shear Stress and Spatial Gradients

ASME 2010 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2010-19662 ◽

2010 ◽

Author(s):

Jennifer Dolan ◽

Song Liu ◽

Hui Meng ◽

John Kolega

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Vessel Wall ◽

Cerebral Aneurysms ◽

In Vivo Studies ◽

Spatial Gradient ◽

Flow Acceleration ◽

Spatial Gradients ◽

Wall Shear

In both human and animal models, cerebral aneurysms tend to develop at the apices of bifurcations in the cerebral vasculature. Due to the focal nature of aneurysm development it has long been speculated that hemodynamics are an important factor in aneurysm susceptibility. The local hemodynamics of bifurcations are complex, being characterized by flow impingement causing a high frictional force on the vessel wall known as wall shear stress (WSS) and significant flow acceleration or deceleration, manifested as the positive or negative spatial gradient of WSS (WSSG). In vivo studies have recently identified that aneurysm initiation occurs at areas of the vessel wall that experience a combination of both high WSS and positive WSSG [1,2]

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The contribution of wall shear stress insult to the growth of small unruptured cerebral aneurysms in longitudinal 3D-TOF-MRA

Journal of the Neurological Sciences ◽

10.1016/j.jns.2020.116798 ◽

2020 ◽

Vol 413 ◽

pp. 116798 ◽

Cited By ~ 1

Author(s):

Lingjun Sun ◽

Jienan Wang ◽

Minghua Li ◽

Mei Li ◽

Yueqi Zhu

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Cerebral Aneurysms ◽

Tof Mra ◽

Wall Shear ◽

Unruptured Cerebral Aneurysms

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Positive and Negative Wall Shear Stress Gradients Have Different Effects on Endothelial Phenotype Under High Wall Shear Stress

ASME 2011 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2011-53490 ◽

2011 ◽

Author(s):

Jennifer Dolan ◽

Frasier Sim ◽

Hui Meng ◽

John Kolega

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Vessel Wall ◽

Cerebral Aneurysms ◽

In Vivo Studies ◽

Spatial Gradient ◽

Cerebral Vasculature ◽

High Wall Shear Stress ◽

Wall Shear

In both human and animal models, cerebral aneurysms tend to develop at the apices of bifurcations in the cerebral vasculature where the blood vessel wall experiences complex hemodynamics. In vivo studies have recently revealed that the initiation of cerebral aneurysms is confined to a well-defined hemodynamic microenvironment [1,2]. Metaxa et al. [2] found that early aneurysm remodeling initiates where the vessel wall experiences high wall shear stress (WSS) and flow is accelerating, thus creating a positive spatial gradient in WSS (WSSG). Closer examination of such in vivo studies reveals that exposure of the vessel wall to equally high WSS in the presence of decelerating flow, that is, negative WSSG, does not result in aneurysm-like destruction.

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Differential Responses of Endothelial Cells to Positive and Negative Wall Shear Stress Gradients

ASME 2010 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2010-19535 ◽

2010 ◽

Author(s):

Jennifer Dolan ◽

Sukhjinder Singh ◽

Hui Meng ◽

John Kolega

Keyword(s):

Shear Stress ◽

Wall Shear Stress ◽

Vessel Wall ◽

Fluid Shear Stress ◽

Cerebral Aneurysms ◽

In Vivo Studies ◽

Outer Side ◽

Fluid Shear ◽

Wall Shear

Cerebral aneurysms tend to develop at bifurcation apices or the outer side of curved vessels where the blood vessel wall experiences complex hemodynamics. In vivo studies have recently revealed that the initiation of cerebral aneurysms is confined to a well-defined hemodynamic microenvironment. Specifically aneurysms form where the vessel wall experiences high fluid shear stress (wall shear stress, WSS) and flow is accelerating, so that the wall is exposed to a positive spatial gradient in the fluid shear stress (wall shear stress gradient, WSSG)[1,2]. Closer examination of such in vivo studies reveals that exposure of the vessel wall to equally high WSS in the presence of decelerating flow, that is, negative WSSG, does not result in aneurysm-like remodeling.

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