Conceptual framework of a novel hybrid methodology between computational fluid dynamics and data mining techniques for medical dataset application

This thesis proposes a novel hybrid methodology that couples computational fluid dynamic (CFD) and data mining (DM) techniques that is applied to a multi-dimensional medical dataset in order to study potential disease development statistically. This approach allows an alternate solution for the present tedious and rigorous CFD methodology being currently adopted to study the influence of geometric parameters on hemodynamics in the human abdominal aortic aneurysm. This approach is seen as a “marriage” between medicine and computer domains

Computer Simulations of Pulsatile Blood Flow in Fusiform Models of Abdominal Aortic Aneurysms

Flow dynamics have been investigated in model aneurysms under physiologically realistic pulsatile flow condition via computational modeling techniques. The computer simulations are based on finite element method. Vortex pattern emergence and evolution were evaluated. Throughout the bulge in all models regardless of size, the systolic flow was found to be forward-directed. Vortices were initially evident in the bulge during deceleration from peak systole and further expanded during the retrograde flow phase. Flow in larger models become increasingly unstable compared to smaller models. It was also noted that these unstable flow fields were much significant towards the distal half of the bulge models. This increased intensity of turbulent flow fields in larger models may contribute significantly to wall shear stress magnitude and subsequently contributing to higher rupture risks. (Abstract by authors

Graphical User Interface (GUI) In MatLab for Solving the Pulsatile Flow in Blood Vessel

Blood flow analysis is a study of measuring the blood pressure and finding its equivalent flow rate, velocity profile and wall shear stress. In this article, the relationship between blood pressure gradient, velocity profile, centreline velocity, volumetric flow rate and wall shear stress is determined analytically through a Graphical User Interface (GUI) developed using MatLab. If one of these time-dependent blood flow properties is known, i.e. pressure gradient, velocity profile, volumetric flow rate or wall shear stress, then the remaining properties can be calculated. A code is developed to solve these blood flow properties. Any time-dependent blood properties can be used as input data. These data are then digitized and saved in this code. Subsequently, these data are curve-fitted using the Fourier series. The corresponding coefficients of Fourier series are then used to calculate the blood property. Once this is obtained, the remaining three other flow properties can be subsequently calculated. This GUI serves as a learning tool for students who wish to pursue his/her knowledge in understanding the relationship of various blood flow properties of pulsatile blood flow as well as the mathematics governing pulsatile flows. (Authors' abstract

Mixed Velocity-Pressure (v-p) Finite Element Method in Assessing the Hemodynamic Wall Shear Stresses in a Fusiform Abdominal Aortic Aneurysm

In this paper, a mixed velocity (v-p) finite element method was used to analyze pulsating blood flow-induced wall shear stress (WSS) in an idealized fusiform abdominal aortic aneurysm (AAA). A three-dimensional mathematical model of the axially symmetric AAA was introduced. The Navier-Stokes and the continuity equations were solved numerically by exploiting the Galerkin method and the fully im-plicit incremental-iterative procedure. A physiologically realistic pulsatile blood flow waveform was im-posed onto the AAA model. This pulsatile condition simulates an in vivo aorta at rest. The developed finite element technique may proof to be useful for biomedical engineers who aim to develop specialized software simulation packages. Computational modeling is becoming a powerful tool in today’s medical treatment planning and predictive methods. Today, clinical application of numerical modeling and computer-aided surgical planning is considered the key for the future of medicine. (Abstract by authors

Finite element computation for solving pulsatile blood flow: relevance in assessing the flow dynamics in abdominal aortic aneurysms

The objective of this paper is to present the mixed velocity-pressure (v-p) finite element method that solves the pulsatile blood flow in arteries. The solution exploits the Galerkin method and the fully implicit incremental-iterative procedure for the three-dimensional nonlinear finite element equations. This methodology is applied to model biological flows that are important in predicting growth and rupture risks in abdominal aortic aneurysms (AAA). The numerical technique was validated with the analytical solution of the Womersley model. Next, a physiologically realistic pulsatile blood flow waveform was imposed onto the idealized cylindrical arterial model and solved as a benchmark problem. The model represents a healthy abdominal aorta. This pulsatile condition simulates an in vivo aorta at rest. The numerical results were used to quantify clinically relevant flow dynamics that play a significant role in today’s field of medical treatment planning and development of predictive methods via computational modelling for assessing common clinical problems such as AAAs

Application of Computational Fluid Dynamics in Assessing the Hemodynamics in Abdominal Aortic Aneurysms

Clinical applications of computational modelling is a fundamentally new approach in medical treatment planning and development of predictive methods. In case of cardiovascular disease, these methods could enable physicians to predict the risk of rupture and to determine the optimal hemodynamic conditions for an individual patient. Abdominal aortic aneurysm (AAA) is a common clinical problem. We present a computational simulation which can be used in the predictive medicine, especially in the diagnosis and treatment of AAAs. For this purpose, we developed a code that provides an integrated set of tools to model clinically relevant hemodynamic conditions important in predicting risk of rupture of AAAs. The blood flow dynamics was solved according to the incompressible Navier- Stokes equations for Newtonian fluids. The pulsatility of blood flow was considered. The computational application is based on the three-dimensional finite element method. A typical idealised fusiform AAA model was used to study the flow effects, flowinduced wall shear stresses and pressure. These three criterias play an important role in assessing the hemodynamics in AAAs. (Abstract by authors

Finite Element Computation for Solving Pulsatile Blood Flow: Relevance in Assessing the Flow Dynamics in Abdominal Aortic Aneurysms

The objective of this paper is to present the mixed velocity-pressure (v-p) finite element method that solves the pulsatile blood flow in arteries. The solution exploits the Galerkin method and the fully implicit incremental-iterative procedure for the three-dimensional nonlinear finite element equations. This methodology is applied to model biological flows that are important in predicting growth and rupture risks in abdominal aortic aneurysms (AAA). The numerical technique was validated with the analytical solution of the Womersley model. Next, a physiologically realistic pulsatile blood flow waveform was imposed onto the idealized cylindrical arterial model and solved as a benchmark problem. The model represents a healthy abdominal aorta.This pulsatile condition simulates an in vivo aorta at rest. The numerical results were used to quantify clinically relevant flow dynamics that play a significant role in today’s field of medical treatment planning and development of predictive methods via computational modelling for assessing common clinical problems such as AAAs. (Authors' abstract