Intracranial Aneurysms CT

Axial CT with IV contrast (angiographic technique) shows a left supraclinoid internal carotid artery aneurysm (arrow), measuring 6-7 mm.
Intracranial Aneurysms

* Dilatation or ballooning of intracranial blood vessel, small <12>25mm
* Three types: fusiform, saccular and dissecting
* Berry aneurysm is of a saccular type
* Common at branch points of large arteries that form the circle of Willis
* Anterior circulation (85% - 95%) > posterior circulation

Symptoms

* Most aneurysms are small and asymptomatic. Large ones may cause mass effect to cranial nerves and brain.
* Rupture usually results in subarachnoid hemorrhage (SAH) with high mortality of up to 50%
* Overall rupture risk is 1.9% per year, higher in women, cigarette smokers, cocaine users, symptomatic aneurysms, >10mm, and located in posterior circulation

Reference:
Ontario Health Technology Advisory Committee. Coil Embolization for Intracranial Aneurysms. January 2006.