Detection of Lumen, Thrombus and Outer Wall Boundaries of an Abdominal Aortic Aneurysm From 2D Medical Images Using Level Set Methods

2008 ◽  
Author(s):  
Georgios Kossioris ◽  
Yannis Papaharilaou ◽  
Christos Zohios
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Arterial Wall ◽  
Aortic Wall ◽  
Level Set Methods ◽  
Outer Wall ◽  
Surrounding Tissue ◽  
Patient Specific ◽  
Rupture Risk ◽  
Abdominal Aortic

Abdominal aortic aneurysm (AAA) is a localized dilatation of the aortic wall. Accurate geometric characterization is critical for a reliable patient specific estimate of AAA rupture risk. However, current imaging modalities do not provide sufficient contrast between thrombus, arterial wall and surrounding tissue thus making the task of segmenting these structures very challenging.

Diet and the content of selenium and lead in patients with abdominal aortic aneurysm

VASA ◽  
2011 ◽  
Vol 40 (5) ◽  
pp. 381-389 ◽  
Author(s):  
Socha ◽  
Borawska ◽  
Gacko ◽  
Guzowski
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Healthy Volunteers ◽  
Arterial Wall ◽  
Aortic Wall ◽  
Dietary Habits ◽  
Absorption Spectrometry ◽  
Control Group ◽  
Abdominal Aortic ◽  
The Mean

Background: To evaluate the content of selenium (Se) and lead (Pb) and the influence of dietary habits and smoking in patients with abdominal aortic aneurysm (AAA). Patients and methods: Forty-nine patients with AAA prior to surgical procedures aged 42 - 81 years and a control group of 22 healthy volunteers aged 31 - 72 years and 17 aortic wall samples from deceased were included in the study. Food-frequency questionnaires were implemented in AAA patients to collect the dietary data. Se and Pb concentrations in the serum and blood, respectively, and in arterial wall and parietal thrombus samples were determined by the atomic absorption spectrometry method. Results: The mean Se level in serum of patients with AAA (60.37 ± 21.2 microg/L) was significantly (p < 0.008) lower than in healthy volunteers (75.87 ± 22.4 microg/L). We observed a significant correlation (r = 0.69, p < 0.0001) between the content of Se in serum and the parietal thrombus of examined patients. Se concentration in aortic wall was inversely correlated to the concentration of Pb (r = - 0.38, p < 0.02). We observed significantly lower (p < 0.05) concentrations of Se (39.14 ± 37.1 microg/g) and significantly higher (p < 0.05) concentrations of Pb (202.69 ± 180.6 microg/g) in aortic wall samples of smoking patients than in non-smoking patients (77.56 ± 70.0 microg/g, 73.09 ± 49.8 microg/g; respectively). Conclusions: Se serum level is lower in patients with AAA than in healthy volunteers. In aortic wall, Se concentration is inversely correlated with Pb concentration. Dietary habits and smoking have an influence on the Se and Pb status in patients with AAA.

scholarly journals Analysis of aortic wall stress and rupture risk in patients with abdominal aortic aneurysm with a gender perspective

2011 ◽  
Vol 54 (2) ◽  
pp. 295-299 ◽  
Author(s):  
Emma Larsson ◽  
Fausto Labruto ◽  
T. Christian Gasser ◽  
Jesper Swedenborg ◽  
Rebecka Hultgren
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Aortic Wall ◽  
Wall Stress ◽  
Rupture Risk ◽  
Gender Perspective ◽  
Abdominal Aortic

A Fluid Structure Interaction Approach for Patient Based Abdominal Aortic Aneurysm Rupture Risk Prediction

2010 ◽  
Author(s):  
Michalis Xenos ◽  
Suraj Rambhia ◽  
Yared Alemu ◽  
Shmuel Einav ◽  
John J. Ricotta ◽  
...  
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Fluid Structure Interaction ◽  
Patient Specific ◽  
Rupture Risk ◽  
Material Models ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Abdominal Aortic ◽  
Risk Of Rupture

Fluid structure interaction (FSI) simulations of patient-specific fusiform non-ruptured and contained ruptured Abdominal Aortic Aneurysm (AAA) geometries were conducted. The goals were: (1) to test the ability of our FSI methodology to predict the location of rupture, by correlating the high wall stress regions with the rupture location, (2) estimate the state of the pathological condition by calculating the ruptured potential index (RPI) of the AAA and (3) predict the disease progression by comparing healthy and pathological aortas. The patient specific AAA FSI simulations were carried out with advanced constitutive material models of the various components of AAA, including models that describe wall anisotropy based on collagen fibers orientation within the arterial wall, structural strength of the aorta, intraluminal thrombus (ILT), and embedded calcifications. The anisotropic material model used to describe the wall properties closely correlated with experimental results of AAA specimens. The results demonstrate that the anisotropic wall simulations showed higher peak wall stresses as compared to isotropic material models, indicating that the latter may underestimate the AAA risk of rupture. The ILT appeared to provide a cushioning effect reducing the stresses, while small calcifications (small-Ca) appeared to weaken the wall and contribute to the rupture risk. FSI simulations with ruptured AAA demonstrated that the location of the maximal wall stresses and RPI overlap the actual rupture region.

Abdominal Aortic Aneurysm Rupture Risk Assessment Exploiting Dynamic (4D) CT Based Wall Motion Data and Finite Element Analysis

2013 ◽  
Author(s):  
Eleni Metaxa ◽  
Vasileios Vavourakis ◽  
Nikolaos Kontopodis ◽  
Konstantinos Pagonidis ◽  
Christos V. Ioannou ◽  
...  
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Risk Estimation ◽  
Wall Stress ◽  
Aneurysm Rupture ◽  
Patient Specific ◽  
Rupture Risk ◽  
Element Analysis ◽  
Motion Data ◽  
Abdominal Aortic

Abdominal aortic aneurysm (AAA) disease is primarily a degenerative process, where rupture occurs when stress exerted on the aortic wall exceeds its failure strength. Therefore, knowledge of both the wall stress distribution and the mechanical properties of the AAA wall is required for patient specific rupture risk estimation.

scholarly journals Predictors of Abdominal Aortic Aneurysm Risks

2020 ◽  
Vol 7 (3) ◽  
pp. 79
Author(s):  
Stephen J. Haller ◽  
Amir F. Azarbal ◽  
Sandra Rugonyi
Keyword(s):  
Risk Assessment ◽  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Wall Stress ◽  
Patient Specific ◽  
Rupture Risk ◽  
Element Analysis ◽  
Computational Biomechanics ◽  
Wall Strength ◽  
Abdominal Aortic

Computational biomechanics via finite element analysis (FEA) has long promised a means of assessing patient-specific abdominal aortic aneurysm (AAA) rupture risk with greater efficacy than current clinically used size-based criteria. The pursuit stems from the notion that AAA rupture occurs when wall stress exceeds wall strength. Quantification of peak (maximum) wall stress (PWS) has been at the cornerstone of this research, with numerous studies having demonstrated that PWS better differentiates ruptured AAAs from non-ruptured AAAs. In contrast to wall stress models, which have become progressively more sophisticated, there has been relatively little progress in estimating patient-specific wall strength. This is because wall strength cannot be inferred non-invasively, and measurements from excised patient tissues show a large spectrum of wall strength values. In this review, we highlight studies that investigated the relationship between biomechanics and AAA rupture risk. We conclude that combining wall stress and wall strength approximations should provide better estimations of AAA rupture risk. However, before personalized biomechanical AAA risk assessment can become a reality, better methods for estimating patient-specific wall properties or surrogate markers of aortic wall degradation are needed. Artificial intelligence methods can be key in stratifying patients, leading to personalized AAA risk assessment.

A Thick-Walled Fluid–Solid-Growth Model of Abdominal Aortic Aneurysm Evolution: Application to a Patient-Specific Geometry

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Andrii Grytsan ◽  
Paul N. Watton ◽  
Gerhard A. Holzapfel
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Vascular Disease ◽  
Arterial Wall ◽  
Cylindrical Tube ◽  
Patient Specific ◽  
Constant Density ◽  
Disease Evolution ◽  
Elastin Degradation ◽  
Abdominal Aortic

We propose a novel thick-walled fluid–solid-growth (FSG) computational framework for modeling vascular disease evolution. The arterial wall is modeled as a thick-walled nonlinearly elastic cylindrical tube consisting of two layers corresponding to the media-intima and adventitia, where each layer is treated as a fiber-reinforced material with the fibers corresponding to the collagenous component. Blood is modeled as a Newtonian fluid with constant density and viscosity; no slip and no-flux conditions are applied at the arterial wall. Disease progression is simulated by growth and remodeling (G&R) of the load bearing constituents of the wall. Adaptions of the natural reference configurations and mass densities of constituents are driven by deviations of mechanical stimuli from homeostatic levels. We apply the novel framework to model abdominal aortic aneurysm (AAA) evolution. Elastin degradation is initially prescribed to create a perturbation to the geometry which results in a local decrease in wall shear stress (WSS). Subsequent degradation of elastin is driven by low WSS and an aneurysm evolves as the elastin degrades and the collagen adapts. The influence of transmural G&R of constituents on the aneurysm development is analyzed. We observe that elastin and collagen strains evolve to be transmurally heterogeneous and this may facilitate the development of tortuosity. This multiphysics framework provides the basis for exploring the influence of transmural metabolic activity on the progression of vascular disease.

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