Aneurysm is a blood-filled bulge in the wall of vessels that occurred in abdominal aortic and cerebral vessels. The dilation of artery leads to aneurysm.

Three dimensional modelling was utilized for a patient with cerebral aneurysm and a normal subject, and additional fluid-structural interaction simulation was performed. We consider pulsatile blood velocity as inlet, and blood pressure as outlet of flow.

The main results including blood velocity, wall shear stress (WSS) of vessel and displacement of wall of vessel. The maximum velocity in normal subject has been 0.2 m/s, that this value in a patient has increased into 0.27 m/s. Blood flow in normal subject and patient remained in limitation of laminar flow and occurrence of aneurysm, has not lead into the turbulent flow. The results showed, WSS in the of vessel after occurrence of aneurysm has increased into 6.3 times greater than normal, which this difference revealed that this parameter was proper index for evaluation of aneurysm. Also, the phase lag of WSS between the normal subject and patient has been 98º that this phase lag was significant in two cases. Due to occurrence of aneurysm, the thickness of the wall decreased during the disease by up to 10% which the continuation of disease progress result in rupture of vessel.

To help the physician, besides analysing hemodynamic parameters of blood flow through non-invasive method, the effective numerical indices (WSS magnitude and WSS phase lag between patient and normal subject) introduced in order to evaluation cerebral aneurysm conditions.