Dissections of brain-supplying arteries.

Arterial dissections involving arteries in the neck and head are being identified increasingly readily because of growing awareness of their clinical features, along with advances in imaging technologies. Dissections are caused mostly by stretching and tearing of arteries, which leads to bleeding within the arterial wall. Dissections of brain-supplying arteries are invariably accompanied by headache and other forms of pain. Subintimal dissections cause mostly brain and eye ischemia, whereas subadventitial dissections lead to formation of aneurysms and pseudoaneurysms and, if the dissection is intracranial, subarachnoid hemorrhage. Dissections are most effectively visualized by conventional angiography, but they can also be imaged by CT or magnetic resonance angiography, fat-saturated MRI cross sections, and ultrasound. Treatment for arterial dissections has not been studied with randomized trial methodology, but most clinicians prescribe antithrombotic medications as prophylaxis. The recurrence rate of infarction or arterial dissections is very low.