The utility of perfusion CT and CT angiography on early diagnosis and the management of vasospasm after subarachnoid hemorrhage

Subarachnoid hemorrhage is one of the most important and dangerous neurologic emergencies worldwide. It is characterized by a sudden and severe headache caused most commonly by the rupture of intracranial aneurysm. Cerebral vasospasm is the most important cause of disability and death in whom survived from the first event. Early diagnosis and management of cerebral vasospasm could prevent and reduce its morbidity and mortality. Thus, an ideal technique must be able to detect the vasospasm before the occurrence of neurological deficits. Perfusion computed tomography could assess vascularity of brain including cerebral blood flow, cerebral blood volume, time to peak and mean transit time. For this application, perfusion computed tomography and computed tomography angiography techniques offer significant advantages and can result in early diagnosis of vasospasm. In this review, we discuss the utility of these two techniques and their safety in the diagnosis and the management of vasospasm following subarachnoid hemorrhage.