Atherosclerosis is a geometrically focal disease and does not occur in a random fashion [1–4]. Angiographic and pathological studies have demonstrated that severe atherosclerotic lesions of intracranial carotid artery are distributed irregularly throughout the vasculature, as some sites are infrequently involved whereas other sites with the arterial commonly harbor significant stenotic lesions [5,6]. However, limited data are available on the segmental distribution of atherosclerotic lesions of …