ABSTRACT
Intracranial arterial disease is a heterogeneous group of diseases that encompasses atherosclerotic to inflammatory and degenerative arteriopathies. Intracranial arteries are divided into two categories: large and small. The term intracranial arterial disease refers to involvement of the large intracranial arteries. Brain arterial embolism is the most common cause of occlusion of a large intracranial artery. There are major differences between the intracranial and coronary arteries and other muscular arteries. The cerebral vessels have no external elastic lamina, and they have a thinner tunica media and trivial adventitia; this makes these vessels quite fragile. Stroke associated with intracranial atherosclerotic disease (ICAD) occurs in association with various stroke mechanisms such as in situ thrombotic occlusion, artery-to-artery embolism, hemodynamic insufficiency, and branch occlusion. Patients with unstable intracranial plaque may show large territorial lesions via sudden thrombotic occlusion. The importance of ICAD as a cause of stroke is underscored as compared to that of extracranial carotid stenosis and nonvalvular atrial fibrillation (AF).
