top of basilar syndrome
Top of the basilar syndrome, also known as rostral brainstem infarction, occurs when there is thromboembolic occlusion of the top of the basilar artery. This results in bilateral thalamic ischemia due to occlusion of perforator vessels.
Clinically, top of the basilar syndrome is characterized by:
- visual and oculomotor deficits
- behavioral abnormalities
- somnolence, hallucinations and dreamlike behavior
- motor dysfunction is often absent
On CT the finding that should not be missed is that of a hyperdense basilar artery. Imaging features are discussed further in the more general article on acute basilar artery occlusion.
Angiography (CT, MR, catheter) can be used to confirm the finding by demonstrating a filling defect.
The pattern of established infarction can be mimicked by:
- artery of Percheron infarct
- bilateral internal cerebral vein thrombosis (dural venous sinus thrombosis)
- other causes of thalamic restricted diffusion