Laboratory for Vascular Simulations
Laboratory’s main objective is to develop computational fluid dynamics (CFD) models to study hemodynamic flow in the cardiovascular system. Pathological conditions such as aneurysms of the abdominal or thoracic aorta, drastically affects blood flow dynamics and create an absolute need for the discovery and analysis of all the mechanical properties involved in the pathology (e.g. pathological flow and pressure fields, stagnation points etc.). The disturbed flow fields arising as a result of these potential pathological conditions have a complex interaction with the peripheral arteries, the elastic vessel walls and the blood itself, composing an important area of research. The interdisciplinary nature of our research includes concepts of medicine, mathematics, engineering and computational fluid dynamics (CFD) and in this context we base the actions of the laboratory for vascular simulations.
Abdominal Aortic Aneurysm (AAA)
Abdominal aortic aneurysm (AAAs) is a localized dilatation (ballooning) of the abdominal aorta exceeding the normal diameter by more than 50 percent. AAAs are most common in patients who have a history of coronary, carotid, or peripheral vascular disease, a history of smoking, or family history of aneurismal disease. In the Laboratory for Vascular Simulations, we apply a novel methodology to patient specific CT data to obtain quantitative information concerning the mechanical properties of AAAs such as velocity and pressure fields, and wall shear stress values. The main stages of our approach are: (i) Acquiring of imaging data through standard clinical approaches, e.g. Computed Tomography (CT). (ii) Reconstruction of abdominal aorta beyond iliac bifurcation for proper observation of AAA pathology. (iii) Discretization of geometry to generate a computational mesh. (iv) This mesh is then exported for computational fluid dynamics (CFD) or for Fluid Structure Interaction (FSI) analysis. An aneurysm in the stage of reconstruction is also displayed.
Hemodynamic Flow in Aortic Arch
The aorta is the main artery that oxygenated blood leaving the heart is pumped through to get to the rest of the body. One of the Lab’s goal is to study the helical and retrograde secondary flow patterns in the aortic arch to explain the alterations in the hemodynamic properties between healthy and pathological cases. Great importance to the success of the simulations is the right choice of initial and boundary conditions. For the current model, except from the parabolic axial velocity, we introduced as an inlet boundary condition a vortex in order to clarify the impact of the heart. The animation presents the hemodynamic flow in a section of the aortic arch. The results were extracted using data from CT scans, image reconstruction software packages and computational fluid dynamics packages.