The role of CT following aneurysmal rupture.

Computed tomography is a highly effective method of detecting subarachnoid blood if performed early after aneurysmal rupture, being 95% to 98% positive when lumbar puncture is positive. The localization of the blood defines the location of the aneurysm in approximately 80% of cases. Contrast enhanced computed tomography demonstrates the aneurysm in 75% of cases with the aneurysm is greater than 5 millimeters in size. Computed tomography angiography defines the aneurysm in up to 96% of cases. The amount of subarachnoid blood correlates with the development of vasospasm; cerebral perfusion can be further evaluated with xenon-enhanced computed tomography.