Atherosclerotic subintimal hematoma of the carotid artery.

A presumed new radiological-pathological entity of atherosclerotic subintimal of the carotid artery is described. Subintimal hematomas were found in 12 of 50 (24%) carotid bifurcations during surgery for repeated transient ischemic attacks in a single hemispheric distribution; only 33% were associated with ulcerations. The typical angiographic appearance was a sharply marginated, rounded, eccentric filling defect located near the extracranial carotid bifurcation, although occasionally it may simulate a typical smooth or even ulcerated atherosclerotic plaque. Pathological mechanisms responsible for the hemorrhage into the atherosclerotic plaque resulting in the hematoma are discussed.