Computed Tomography in the Diagnosis of Subarachnoid Haemorrhage

Abstract

Early computed tomography (CT) is very useful in detecting subarachnoid haemorrhage (SAH). It offers a lot of information about the origin, the extent of the haemorrhage and the early complications (hydrocephalus, haematoma). Moreover, CT scan can suggest the site of bleeding aneurysm and the risk of severe vasospasm. In some cases, CT shows a perimesencephalic SAH in which often no aneurysm can be detected. The sensitivity of CT in demonstrating SAH decreases as the time between onset of SAH and CT scanning increases.