Abstract
(1) Primary changes should be the development of the stenosis in the form of the intimal proliferation and a “cluster” of the fine vessel groups should be the secondary.
(2) Angiographic pictures of the cerebral arterial rate consist of the number of the perforating vessels primarily.
(3) Histological findings and angioarchitectural pattern of the stenosed part of the vessel suggest an abnormal proliferation of a “Polster”.
(4) Intracerebral vessels showed a various patterns of newly developed collateral circuits as well as the proliferation of a “Polster”. These mechanisms are discussed.