This study investigates the hemodynamic efficiency of endovascular coiling in the treatment of patient-specific middle cerebral artery (MCA) aneurysms using computational models of both original and scaled-down geometries. Computational fluid dynamic (CFD) is used for the blood flow modelling inside cerebral aneurysms. The Casson non-Newtonian model is employed to simulate blood flow dynamics, while a porous condition represents the coiling within the aneurysm sac. Key hemodynamic factors, including wall shear stress (WSS) and oscillatory shear index (OSI), are analyzed to evaluate the effectiveness of coiling across different aneurysm sizes. Results indicate that coiling significantly reduces rupture risk, with larger sac volumes demonstrating a more pronounced decrease in high-risk hemodynamic zones. These findings offer insights into optimizing endovascular treatments for varying aneurysm morphologies.