Cerebral vasospasm is considered a common and serious complication of aneurysmal subarachnoid hemorrhage (SAH), contributing to elevated rates of morbidity and mortality. Cerebral ischemia due to vasospasm has traditionally been thought to result from reductions in cerebral blood flow through constricted vessels. Recently, cerebral ischemia associated with vasospasm is considered as a result of complex interactions among cerebral blood flow [1], metabolism and inflammation. Some authors have observed thrombi in aneurysmal sac and vessels in which vasospasm had resulted in cerebral ischemia. Thrombus in the aneurysmal sac may result from turbulence and slow blood flow and can act as a source of distal embolization. However their origin remains unclear as does their contribution to brain ischemia.