Purpose: To describe clinical, radiological and pathological-anatomical findings of basilar artery dissections.
Methods: During a period of three years (1994-1996) we observed 4 patients with dissections of the basilar artery, proven by angiography. Angiograms, MRI (n = 2) and autopsy results (n = 1) of these patients were correlated with clinical symptoms and long-term follow-up.
Results: In three patients the dissection was confined into the basilar artery. Three patients with vertebrobasilar ischaemia showed irregularities of the vessel wall on angiography, in one of these patients autopsy revealed a haematoma within the vessel wall, located between intima and media. One patient complaining of relapsing headaches had a posttraumatic basilar artery aneurysm.
Conclusion: Dissections of the basilar artery can be separated in two types. In case of subintimal dissection patients present with vertebrobasilar ischaemia, which in contrast to extracranial dissections usually occurs without temporal delay. A second type of patients presents with subarachnoid haemorrhage. The dissection is subadventitial and pierces through a thin adventitia into the subarachnoid space.