High-quality conforming hexahedral meshes of patient-specific abdominal aortic aneurysms including their intraluminal thrombi

Tarjuelo-Gutiérrez, J.; Rodríguez-Vila, B.; Pierce, David M.; Fastl, Thomas; Verbrugghe, Peter; Fourneau, Inge; Maleux, Geert; Herijgers, Paul; Holzapfel, Gerhard; Gómez, Enrique J.

doi:10.1007/s11517-013-1127-5

Cited by 11 publications

(16 citation statements)

References 21 publications

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“…Moreover, an increased number of elements nonlinearly increases the solution times. If accounting for the layered morphology and non-uniform thickness, conformal projection-based methods in De Santis et al (2011), Tarjuelo-Gutierrez et al (2014, Auer and Gasser (2010) appear effective. The thickness direction should be represented with sufficient elements to represent stress gradients through the bulk of the aorta -generally 3-6 layers.…”

Section: Meshing and Mechanical Model Of Aaas For Fe Analysismentioning

confidence: 99%

“…The geometric representation of this material separation therefore necessarily contains (poor quality) collapsed "wedge" elements, regardless of the meshing algorithm or even mesh density (Tarjuelo-Gutierrez et al, 2014).…”

Section: Meshing and Mechanical Model Of Aaas For Fe Analysismentioning

confidence: 99%

“…Nevertheless, since MRI can capture lumen/ILT/aortic wall separation, it allows for more precise approximation through statistically-based avenues of obtaining representative layer thicknesses (Tarjuelo-Gutierrez et al, 2014).…”

Section: Shortcomings In Light Of Rupture Risk Assessmentmentioning

confidence: 99%

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Rupture risk in abdominal aortic aneurysms: A realistic assessment of the explicit GPU approach

Štrbac

Pierce

Rodríguez-Vila

et al. 2017

Journal of Biomechanics

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Accurate estimation of peak wall stress (PWS) is the crux of biomechanically motivated rupture risk assessment for abdominal aortic aneurysms aimed to improve clinical outcomes. Such assessments often use the finite element (FE) method to obtain PWS, albeit at a high computational cost, motivating simplifications in material or element formulations. These simplifications, while useful, come at a cost of reliability and accuracy. We achieve research-standard accuracy and maintain clinically applicable speeds by using novel computational technologies. We present a solution using our custom finite element code based on graphics processing unit (GPU) technology that is able to account for added complexities involved with more physiologically relevant solutions, e.g. strong anisotropy and heterogeneity. We present solutions up to 17x faster relative to an established finite element code using state-of-the-art nonlinear, anisotropic and nearly-incompressible material descriptions. We show a realistic assessment of the explicit GPU FE approach by using complex problem geometry, biofidelic material law, doubleprecision floating point computation and full element integration. Due to the increased solution speed without loss of accuracy, shown on five clinical cases of abdominal aortic aneurysms, the method shows promise for clinical use in determining rupture risk of abdominal aortic aneurysms.

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Section: Meshing and Mechanical Model Of Aaas For Fe Analysismentioning

confidence: 99%

Section: Meshing and Mechanical Model Of Aaas For Fe Analysismentioning

confidence: 99%

See 1 more Smart Citation

Rupture risk in abdominal aortic aneurysms: A realistic assessment of the explicit GPU approach

Štrbac

Pierce

Rodríguez-Vila

et al. 2017

Journal of Biomechanics

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“…If there were no contraindications, we performed Magnetic Resonance Imaging (MRI) studies using a 1.5 T scanner (Aera; Siemens, Erlangen, Germany) and the protocol outlined in Tarjuelo-Gutiérrez et al [35]. * We collected three sets of patient-specific MR Images from patients with an AAA having a diameter of greater then 5 cm.…”

Section: Patient-specific Geometries and Meshesmentioning

confidence: 99%

“…* We collected three sets of patient-specific MR Images from patients with an AAA having a diameter of greater then 5 cm. We segment and process the MRI data (axial slices) to generate our patient-specific geometries following the approach of Tarjuelo-Gutiérrez et al [35]. Thus, we delineate three 3-D binary images: the outer arterial wall contour, the lumen contour and the thrombus contour (where ILT exists).…”

Section: Patient-specific Geometries and Meshesmentioning

confidence: 99%

A method for incorporating three-dimensional residual stretches/stresses into patient-specific finite element simulations of arteries

Pierce

Fastl

Rodríguez-Vila

et al. 2015

Journal of the Mechanical Behavior of Biomedical Materials

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The existence of residual stresses in human arteries has long been shown experimentally. Researchers have also demonstrated that residual stresses have a significant effect on the distribution of physiological stresses within arterial tissues, and hence on their development, e.g., stress-modulated remodeling. Through progress in medical imaging, image analysis and finite element (FE) meshing tools it is now possible to construct in vivo patient-specific geometries and thus to study specific, clinically relevant problems in arterial mechanics via FE simulations. Classical continuum mechanics and FE methods assume that constitutive models and the corresponding simulations start from unloaded, stress-free reference configurations while the boundary-value problem of interest represents a loaded geometry and includes residual stresses. We present a pragmatic methodology to simultaneously account for both (i) the three-dimensional (3-D) residual stress distributions in the arterial tissue layers, and (ii) the equilibrium of the in vivo patient-specific geometry with the known boundary conditions. We base our methodology on analytically determined residual stress distributions (Holzapfel and Ogden, 2010, J. R. Soc. Interface 7, 787-799) and calibrate it using data on residual deformations (Holzapfel et al., 2007, Ann. Biomed. Eng. 35, 530-545). We demonstrate our methodology on three patient-specific FE simulations calibrated using experimental data. All data employed here are generated from human tissues - both the aorta and thrombus, and their respective layers - including the geometries determined from magnetic resonance images, and material properties and 3-D residual stretches determined from mechanical experiments. We study the effect of 3-D residual stresses on the distribution of physiological stresses in the aortic layers (intima, media, adventitia) and the layers of the intraluminal thrombus (luminal, medial, abluminal) by comparing three types of FE simulations: (i) conventional calculations; (ii) calculations accounting only for prestresses; (iii) calculations including both 3-D residual stresses and prestresses. Our results show that including residual stresses in patient-specific simulations of arterial tissues significantly impacts both the global (organ-level) deformations and the stress distributions within the arterial tissue (and its layers). Our method produces circumferential Cauchy stress distributions that are more uniform through the tissue thickness (i.e., smaller stress gradients in the local radial directions) compared to both the conventional and prestressing calculations. Such methods, combined with appropriate experimental data, aim at increasing the accuracy of classical FE analyses for patient-specific studies in computational biomechanics and may lead to increased clinical application of simulation tools.

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A quarter of a century biomechanical rupture risk assessment of abdominal aortic aneurysms. Achievements, clinical relevance, and ongoing developments

Gasser

Miller

Polzer

et al. 2022

Numer Methods Biomed Eng

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Abdominal aortic aneurysm (AAA) disease, the local enlargement of the infrarenal aorta, is a serious condition that causes many deaths, especially in men exceeding 65 years of age. Over the past quarter of a century, computational biomechanical models have been developed towards the assessment of AAA risk of rupture, technology that is now on the verge of being integrated within the clinical decision-making process. The modeling of AAA requires a holistic understanding of the clinical problem, in order to set appropriate modeling assumptions and to draw sound conclusions from the simulation results. In this article we summarize and critically discuss the proposed modeling approaches and report the outcome of clinical validation studies for a number of biomechanics-based rupture risk indices. Whilst most of the aspects concerning computational mechanics have already been settled, it is the exploration of the failure properties of the AAA wall and the acquisition of robust input data for simulations that has the greatest potential for the further improvement of this technology. K E Y W O R D Sabdominal aortic aneurysm, modeling, ruptuer risk assessment, vascular biomechanics | WHAT IS AAAWhilst an aneurysm, a permanent local enlargement of an artery by more than 50% of its diameter, may affect all arteries, the infrarenal aorta is most vulnerable to this disease and often leads to the development of an abdominal aortic aneurysm (AAA). The formation of AAAs is promoted by factors such as old age, male gender, smoking, and high mean arterial pressure (MAP). Furthermore, it is over-represented in persons with a family history of AAA and patients with coronary heart disease and Chronic Obstructive Pulmonary Disease. Aortic aneurysms can also present in patients with rare genetic diseases, such as Ehlers-Danlos syndrome type IV, Marfan syndrome, Loeys-Dietz syndrome, and fibromuscular dysplasia. Most AAAs remain small and therefore do not necessitate clinical intervention. However, an aneurysm may grow to a size that could result in aortic rupture, a life-threatening event. In urban areas only 50% of

show abstract

High-quality conforming hexahedral meshes of patient-specific abdominal aortic aneurysms including their intraluminal thrombi

Cited by 11 publications

References 21 publications

Rupture risk in abdominal aortic aneurysms: A realistic assessment of the explicit GPU approach

Rupture risk in abdominal aortic aneurysms: A realistic assessment of the explicit GPU approach

A method for incorporating three-dimensional residual stretches/stresses into patient-specific finite element simulations of arteries

A quarter of a century biomechanical rupture risk assessment of abdominal aortic aneurysms. Achievements, clinical relevance, and ongoing developments

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