Computational study of hemodynamics analysis between mri measurement and cfd simulation on segmented patient-specific cerebral aneurysm model /
Lim Sheh Hong
- xiii, 144 pages : illustrations (some color) ; 30 cm. + 1 CD ROM
College of Engineering
Thesis (Master of Science) -- Universiti Malaysia Pahang β 2021
Includes bibliographical references
The implementation of computational fluid dynamics (CFD) analysis was extensively performed to investigate the hemodynamics using segmented patient-specific cerebral aneurysm model geometry reconstructed from a medical image in this research. According to previous studies, the low-resolution magnetic resonance imaging (MRI) medical image produces a high measurement error and leads to inaccurate hemodynamics approximations with a large velocity difference of approximately 40 % between MRI measurement and CFD simulation. Besides, setting patient-specific boundary conditions before CFD analysis is critical, but there is no unified rule, especially for the setup of model geometry with bifurcation, which requires multiple outlet boundaries. Therefore, this study investigated the extracted model geometry with different threshold coefficients, πΆπ‘βπππ , through image segmentation process on the patient-specific cerebral aneurysm and to evaluate the hemodynamics factors for cerebral aneurysms using digital subtraction angiography (DSA) and MRI medical images with the implementation of pressure fixed (P-fixed) approach as well as MRI measurement, which are the crucial elements in achieving the objectives. Moreover, the average relative error, Er,avg, upon steady-state simulation, was used to examine the trend of average velocity, Vavg, and maximum velocity, Vmax, between MRI measurement and CFD simulation. This study concluded that the cerebral aneurysm model geometry extraction with different threshold values has profound effects on physical and hemodynamics parameters. The optimised cerebral aneurysm model geometry was found at threshold coefficients, πΆπ‘βπππ , ranging from 0.3 to 0.5. Nevertheless, high wall shear stress (WSS) distribution, pressure distribution, and velocity flow field are among the hemodynamics factors contributing to the cerebral aneurysm growing and rupturing. This study also found a velocity flow field difference with average relative error, Er,avg, of 11.6723 % and 37.3647 %, in terms of average velocity, Vavg, and maximum velocity, Vmax, respectively, between MRI measurement and CFD simulation through the P-fixed approach.