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Effects of Variations of Flow and Heart Rate on Intra-Aneurysmal Hemodynamics in a Ruptured Internal Carotid Artery Aneurysm During Exercise.

Sarrami-Foroushani A, Nasr Esfahany M, Saligheh Rad H, Firouznia K, Shakiba M, Ghanaati H - Iran J Radiol (2016)

Bottom Line: The intra-aneurysmal hemodynamic environments for three states with different flow and heart rates were analyzed using patient-specific image-based CFD modeling.Results showed significant changes for the three simulated states.For a proportion of the states examined, results were counterintuitive.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Engineering, Isfahan University of Technology, Isfahan, Iran.

ABSTRACT

Background: Hemodynamics is thought to play an important role in the mechanisms responsible for initiation, growth, and rupture of intracranial aneurysms. Computational fluid dynamic (CFD) analysis is used to assess intra-aneurysmal hemodynamics.

Objectives: This study aimed to investigate the effects of variations in heart rate and internal carotid artery (ICA) flow rate on intra-aneurysmal hemodynamics, in an ICA aneurysm, by using computational fluid dynamics.

Patients and methods: Computed tomography angiography (CTA) was performed in a 55 years old female case, with a saccular ICA aneurysm, to create a patient-specific geometrical anatomic model of the aneurysm. The intra-aneurysmal hemodynamic environments for three states with different flow and heart rates were analyzed using patient-specific image-based CFD modeling.

Results: Results showed significant changes for the three simulated states. For a proportion of the states examined, results were counterintuitive. Systolic and time-averaged wall shear stress and pressure on the aneurysm wall showed a proportional evolution with the mainstream flow rate.

Conclusion: Results reinforced the pivotal role of vascular geometry, with respect to hemodynamics, together with the importance of performing patient-specific CFD analyses, through which the effect of different blood flow conditions on the aneurysm hemodynamics could be evaluated.

No MeSH data available.


Related in: MedlinePlus

Reconstructed 3D model used for CFD Simulations
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fig23829: Reconstructed 3D model used for CFD Simulations

Mentions: CTA was performed on a 55 years old female with a saccular aneurysm in the ICA, on GE Lightspeed VCT 64-slice scanner (General Electric Healthcare, Milwaukee, WI, USA) in Imam Khomeini Hospital, Tehran, Iran. A 3D patient-specific geometric model of the aneurysm was constructed after segmentation of 3D CTA images in Materialise MIMICS (Materialise NV, Leuven, Belgium) (Figure 1). The geometric model is then used to generate a volumetric computational unstructured mesh of 2795046 elements in ANSYS ICEM CFD (Ansys Inc., Canonsburg, PA, USA). Blood flow was modeled by unsteady 3D Navier-Stokes equations for incompressible Newtonian fluid. Blood is assumed to be a homogeneous Newtonian fluid of density 1066 kg/m3 and viscosity 0.0035 Pa∙s. The assumption of blood, as a Newtonian fluid, is demonstrated to be reasonable in large vessels with high shear rate (18). Despite compliance of the vessel walls, due to the lack of elastin in cerebral arteries (19), vessels were assumed to be rigid, with a no slip boundary condition at walls. Pressure waveforms, obtained from one-dimensional global analysis of systemic arterial tree (20), were prescribed as the outlet boundary conditions at the outlets, i.e. anterior communicating artery (ACA) and middle cerebral artery (MCA).


Effects of Variations of Flow and Heart Rate on Intra-Aneurysmal Hemodynamics in a Ruptured Internal Carotid Artery Aneurysm During Exercise.

Sarrami-Foroushani A, Nasr Esfahany M, Saligheh Rad H, Firouznia K, Shakiba M, Ghanaati H - Iran J Radiol (2016)

Reconstructed 3D model used for CFD Simulations
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837368&req=5

fig23829: Reconstructed 3D model used for CFD Simulations
Mentions: CTA was performed on a 55 years old female with a saccular aneurysm in the ICA, on GE Lightspeed VCT 64-slice scanner (General Electric Healthcare, Milwaukee, WI, USA) in Imam Khomeini Hospital, Tehran, Iran. A 3D patient-specific geometric model of the aneurysm was constructed after segmentation of 3D CTA images in Materialise MIMICS (Materialise NV, Leuven, Belgium) (Figure 1). The geometric model is then used to generate a volumetric computational unstructured mesh of 2795046 elements in ANSYS ICEM CFD (Ansys Inc., Canonsburg, PA, USA). Blood flow was modeled by unsteady 3D Navier-Stokes equations for incompressible Newtonian fluid. Blood is assumed to be a homogeneous Newtonian fluid of density 1066 kg/m3 and viscosity 0.0035 Pa∙s. The assumption of blood, as a Newtonian fluid, is demonstrated to be reasonable in large vessels with high shear rate (18). Despite compliance of the vessel walls, due to the lack of elastin in cerebral arteries (19), vessels were assumed to be rigid, with a no slip boundary condition at walls. Pressure waveforms, obtained from one-dimensional global analysis of systemic arterial tree (20), were prescribed as the outlet boundary conditions at the outlets, i.e. anterior communicating artery (ACA) and middle cerebral artery (MCA).

Bottom Line: The intra-aneurysmal hemodynamic environments for three states with different flow and heart rates were analyzed using patient-specific image-based CFD modeling.Results showed significant changes for the three simulated states.For a proportion of the states examined, results were counterintuitive.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Engineering, Isfahan University of Technology, Isfahan, Iran.

ABSTRACT

Background: Hemodynamics is thought to play an important role in the mechanisms responsible for initiation, growth, and rupture of intracranial aneurysms. Computational fluid dynamic (CFD) analysis is used to assess intra-aneurysmal hemodynamics.

Objectives: This study aimed to investigate the effects of variations in heart rate and internal carotid artery (ICA) flow rate on intra-aneurysmal hemodynamics, in an ICA aneurysm, by using computational fluid dynamics.

Patients and methods: Computed tomography angiography (CTA) was performed in a 55 years old female case, with a saccular ICA aneurysm, to create a patient-specific geometrical anatomic model of the aneurysm. The intra-aneurysmal hemodynamic environments for three states with different flow and heart rates were analyzed using patient-specific image-based CFD modeling.

Results: Results showed significant changes for the three simulated states. For a proportion of the states examined, results were counterintuitive. Systolic and time-averaged wall shear stress and pressure on the aneurysm wall showed a proportional evolution with the mainstream flow rate.

Conclusion: Results reinforced the pivotal role of vascular geometry, with respect to hemodynamics, together with the importance of performing patient-specific CFD analyses, through which the effect of different blood flow conditions on the aneurysm hemodynamics could be evaluated.

No MeSH data available.


Related in: MedlinePlus