Nowadays cardiovascular diseases (CVDs), mostly coronary artery diseases become a leading cause of death. Flow dynamics of a vessel is important to diagnose a CVD in advance. However, hemodynamic parameters may not be measured directly. Hence, computational methods are increasingly being used in the fields of neurosurgery and cardiovascular surgery to obtain realistic physiological simulations. In this study, a patient specific thoracic artery model is first segmented based on the MRI images and then a thoracic aneurysm disease model is simulated to assess blood flow changes under the predefined conditions.