Aortic dissection typically presents with severe chest or back pain.

Neurological symptoms may occur because of occlusion of supplying vessels or general hypotension from blood loss within the thorax.

Stranford Classification is the most commonly used system. Type A dissections involves the ascending aorta, and can lead to stroke, while the type B the distal section below the origin of the subclavian artery is involved.

Post Caridac arrest with more than 5min of downtime. 

Symptomatic carotid artery disease is a significant cause of ischemic stroke, and these patients are at high risk for recurrent vascular events. In this case it lead to watershed infarcts.

See the Infarct Pattern

From the Arch or the Carotid biforcation