Cerebral aneurysms are thin walled and stiffer compared with a normal artery. The current work describes fluid structure interaction (FSI) simulations in a patient specific model of a cerebral aneurysm located in the ophthalmic region, using different wall thickness and elastic modulus for the artery and aneurysm. The geometry was reconstructed from a three dimensional angiography examination. The wall was assumed as elastic shell with variable thickness. The FSI model was calculated using the finite elements software ADINA. The fluid dynamics and solid mechanics predictions on the aneurysm wall were reported.