Multiaxial Mechanical Behavior of Human Saccular Aneurysms

Seshaiyer, Padmanabhan; Hsu, FangHua; Shah, Aamir S.; Kyriacou, S.K.; Humphrey, Jay D.

doi:10.1080/10255840108908009

Cited by 52 publications

(60 citation statements)

References 14 publications

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“…The average wall thickness of cerebral aneurysms measured in [2,21] are 0.11 and 0.086 mm, respectively. Cerebral aneurysms exhibit a nonlinear response over finite strains that is typical for soft biological tissues [21]; however, for pressure of 100 mmHg the aneurysm wall stretch ratio is only around 1.05 [21].…”

Section: Governing Equations For Fsimentioning

confidence: 99%

Blood flow dynamics and fluid–structure interaction in patient‐specific bifurcating cerebral aneurysms

Valencia

Ledermann

Rivera

et al. 2008

Numerical Methods in Fluids

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SUMMARYHemodynamics plays an important role in the progression and rupture of cerebral aneurysms. The current work describes the blood flow dynamics and fluid-structure interaction in seven patient-specific models of bifurcating cerebral aneurysms located in the anterior and posterior circulation regions of the circle of Willis. The models were obtained from 3D rotational angiography image data, and blood flow dynamics and fluid-structure interaction were studied under physiologically representative waveform of inflow. The arterial wall was assumed to be elastic, isotropic and homogeneous. The flow was assumed to be laminar, non-Newtonian and incompressible. In one case, the effects of different model suppositions and boundary conditions were reported in detail. The fully coupled fluid and structure models were solved with the finite elements package ADINA. The vortex structure, pressure, wall shear stress (WSS), effective stress and displacement of the aneurysm wall showed large variations, depending on the morphology of the artery, aneurysm size and position. The time-averaged WSS, effective stress and displacement at the aneurysm fundus vary between 0.17 and 4.86 Pa, 4.35 and 170.2 kPa and 0.16 and 0.74 mm, respectively, for the seven patient-specific models of bifurcating cerebral aneurysms.

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Section: Governing Equations For Fsimentioning

confidence: 99%

Blood flow dynamics and fluid–structure interaction in patient‐specific bifurcating cerebral aneurysms

Valencia

Ledermann

Rivera

et al. 2008

Numerical Methods in Fluids

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“…Although the diameter of ICAs can exceed 30 mm, the wall thickness ranges from 16 to 500 µm (Humphrey and Canham 2000;Seshaiyer et al 2001). Mechanical tests indicated that the wall tissue has negligible bending stiffness (Humphrey and Canham 2000).…”

mentioning

confidence: 97%

Inverse method of stress analysis for cerebral aneurysms

Zhou

Raghavan

2007

Biomech Model Mechanobiol

130

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We present a method for predicting the wall stress in a class of cerebral aneurysms. The method hinges on an inverse formulation of the elastostatic equilibrium problem; it takes as the input a deformed configuration and the corresponding pressure, and predicts the wall stress in the given deformed state. For a membrane structure, the inverse formulation possesses a remarkable feature, that is, it can practically determine the wall tension without accurate knowledge of the wall elastic properties. In this paper, we present a finite element formulation for the inverse membrane problem and perform material sensitivity studies on idealized lesions and an image-based cerebral aneurysm model.

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“…Indeed, one of the potentially most important applications of this method would be to characterize evolving properties, as, for example, of intracranial aneurysms or models thereof. It was suggested years ago that regional variations in aneurysmal properties could be mechanically and mechanbiologically favourable [28], but there has yet to be a detailed assessment [29]. As noted earlier, without detailed information on potentially evolving, regionally varying material properties of any tissue or organ, our understanding of both the mechanics and mechanobiology will remain limited.…”

Section: Discussionmentioning

confidence: 99%

Digital image correlation-based point-wise inverse characterization of heterogeneous material properties of gallbladder in vitro

et al. 2014

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Continuing advances in mechanobiology reveal more and more that many cell types, especially those responsible for establishing, maintaining, remodelling or repairing extracellular matrix, are extremely sensitive to their local mechanical environment. Indeed, it appears that they fashion the extracellular matrix so as to promote a ‘mechanical homeostasis’. A natural corollary, therefore, is that cells will try to offset complexities in geometry and applied loads with heterogeneous material properties in order to render their local environment mechanobiologically favourable. There is a pressing need, therefore, for hybrid experimental–computational methods in biomechanics that can quantify such heterogeneities. In this paper, we present an approach that combines experimental information on full-field surface geometry and deformations with a membrane-based point-wise inverse method to infer full-field mechanical properties for soft tissues that exhibit nonlinear behaviours under finite deformations. To illustrate the potential utility of this new approach, we present the first quantification of regional mechanical properties of an excised but intact gallbladder, a thin-walled, sac-like organ that plays a fundamental role in normal digestion. The gallbladder was inflated to a maximum local stretch of 120% in eight pressure increments; at each pressure pause, the entire three-dimensional surface was optically extracted, and from which the surface strains were computed. Wall stresses in each state were predicted from the deformed geometry and the applied pressure using an inverse elastostatic method. The elastic properties of the gallbladder tissue were then characterized locally using point-wise stress–strain data. The gallbladder was found to be highly heterogeneous, with drastically different stiffness between the hepatic and the serosal sides. The identified material model was validated through forward finite-element analysis; both the configurations and the local stress–strain patterns were well reproduced.

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Multiaxial Mechanical Behavior of Human Saccular Aneurysms

Cited by 52 publications

References 14 publications

Blood flow dynamics and fluid–structure interaction in patient‐specific bifurcating cerebral aneurysms

Blood flow dynamics and fluid–structure interaction in patient‐specific bifurcating cerebral aneurysms

Inverse method of stress analysis for cerebral aneurysms

Digital image correlation-based point-wise inverse characterization of heterogeneous material properties of gallbladder in vitro

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