Dissecting Vertebrobasilar Aneurysm
Findings:
Vertebral DSA demonstrates smooth tapered stenosis of
the vertebral artery on both sides of a large aneurysm.
Discussion:
Dissecting aneurysms may arise spontaneously without
history of trauma. Alternatively, they may be traumatic or related to underlying
vasculopathy. These aneurysms result from rupture of the medial dissecting
hematoma into the adventitia. Smooth tapered stenosis related to the aneurysm
is a characteristic imaging feature, called the "pearl and string" sign.
Dissecting aneurysms are most common in the extracranial segments of the
ICA and vertebral arteries. Embolic phenomena and rupture may occur.