**2. Reconstruction of the AAA endograft model**

Finite Volume Analysis technique has a crucial role in the computational research of hemodynamic systems, utilizing small subsections (elements) of 3-dimentional structures created by segmentation and meshing. By solving Navier-Stokes equations for all finite volumes of the model, Computational flow dynamics (CFD) techniques utilize numerical methods and algorithms to analyze problems that involve fluid flows. Furthermore, Fluid Structure Interaction (FSI) methods combine fluid and structural equations, solved either simultaneously or separately (partitioned approach), in order to determine the flow fields and solid body stresses on a deformable model. Most researchers acquire information on the 3D AAA realistic, complex geometry using patient-specific DICOM data derived from highresolution spiral CT or MR angiography (Georgakarakos et al, 2012b).

Our study group used a reconstructed 3D model of a AAA endograft using commercially available appropriate, validated software (MIMICS 13.0, Materialise NV, Leuven, Belgium), based on the DICOM images derived from contrast-enhanced high-resolution computed tomography. The computational model (**Figure1**) includes the aortic neck proximal to the endograft and the iliac arteries distal to the endograft limbs. A validated Finite Volume analysis software ANSYS v 12.1 (Ansys Inc., Canonsburg, PA, USA) was used for Computational Fluid Dynamics (CFD). The velocity and pressure waveforms during a period of 1.2 s as previously described in a one-dimensional fluid-dynamics model for the abdominal aorta (Olufsen et al, 2000 and Li et al, 2005) were used for both models as inlet and outlet boundary conditions. Blood was assumed to be non-Newtonian fluid, according to the Carreau-Yasuda model, with a density of 1050 kg/m3.

**Figure 1.** Reconstructed images of the aortic endograft using purpose-developed software.

Accordingly, the velocity streamlines and the pressure distribution were calculated over the entire surface of the endograft and are demonstrated in 6 distinct time-phases through the cardiac cycle (**Figure2**). For study reasons, the cardiac cycle was dived in six distinct phases, namely the late diastole (t1), the accelerating systolic phase (t2), the peak systolic phase (t3), the late deceleration (t4), the end-systolic (t5) and the early diastolic phase (t6).

152 Aneurysm

**2. Reconstruction of the AAA endograft model** 

resolution spiral CT or MR angiography (Georgakarakos et al, 2012b).

to the Carreau-Yasuda model, with a density of 1050 kg/m3.

**Figure 1.** Reconstructed images of the aortic endograft using purpose-developed software.

Finite Volume Analysis technique has a crucial role in the computational research of hemodynamic systems, utilizing small subsections (elements) of 3-dimentional structures created by segmentation and meshing. By solving Navier-Stokes equations for all finite volumes of the model, Computational flow dynamics (CFD) techniques utilize numerical methods and algorithms to analyze problems that involve fluid flows. Furthermore, Fluid Structure Interaction (FSI) methods combine fluid and structural equations, solved either simultaneously or separately (partitioned approach), in order to determine the flow fields and solid body stresses on a deformable model. Most researchers acquire information on the 3D AAA realistic, complex geometry using patient-specific DICOM data derived from high-

Our study group used a reconstructed 3D model of a AAA endograft using commercially available appropriate, validated software (MIMICS 13.0, Materialise NV, Leuven, Belgium), based on the DICOM images derived from contrast-enhanced high-resolution computed tomography. The computational model (**Figure1**) includes the aortic neck proximal to the endograft and the iliac arteries distal to the endograft limbs. A validated Finite Volume analysis software ANSYS v 12.1 (Ansys Inc., Canonsburg, PA, USA) was used for Computational Fluid Dynamics (CFD). The velocity and pressure waveforms during a period of 1.2 s as previously described in a one-dimensional fluid-dynamics model for the abdominal aorta (Olufsen et al, 2000 and Li et al, 2005) were used for both models as inlet and outlet boundary conditions. Blood was assumed to be non-Newtonian fluid, according

**Figure 2.** Plot of the flow waveform used for the calculations in our endograft model (left panel). Six distinct phases are depicted in each cardiac cycle. t1 depicts the late diastole, t2 the accelerating phase, t3 represents the peak systolic phase, t4 the late deceleration, t5 depicts the end-systole and t6 the early diastolic phase (right panel).
