抄録
The purpose of the present study is to observe the vasa vasorum of human intracranial arteries and to discuss their role in the development of cerebral atherosclerosis and thrombosis.
Postmorten angiography was performed in 24 cases and 67 cases were examined histologically. Serial section technique was employed in 21 cases with cerebral thrombosis.
Adventitial vasa vasorum, which were derived from the small branches of the intracranial arteries or from the vasa vasorum of the extracranial arteries, were always seen in the proximal part of the vertebral artery, and were seen in 44.4% of its distal part. They were found in 16.0% of the distal part of the basilar artery, 46.8% of the intracranial internal carotid artery and less frequently in more peripheral arteries.
Two types of intimal vasculature were distinguished: one originated from the adventitial vasa vasorum and the other from the arterial lumen. The adventitial vasa vasorum occasionally penetrated into the media and even into the thickened intima through disrupted internal elastic lamina, where the arterial lumen was narrowed more than 40%.
Intimal vascularization from the arterial lumen was seen in the arteries over 40% of narrowing and was more frequently found in the arterial segments with thrombi. However, it was less frequent in the intracranial arteries than in the coronary artery. Intimal vasculature showed several pathologic changes such as marked dilatation, stenosis, obstruction and hemorrhage. Intimal vessels distributed in deeper layers of the laminated thickened intima. These intimal thickening was usually eccentric and atheromatous necrosis was also localized in each layer accompaning foam cell accumulation and hemosiderin deposition.
These findings suggested that the eccentrically thickened intima with intimal vascularization was a sequel of the organization of thrombus. In the vertebral, basilar and internal carotid arteries, the adventitial vasa vasorum penetrated into the thickened intima through disrupted internal elastic lamina and anastomosed with intimal capillaries from the arterial lumen. This fact also suggests an important role of the adventitial vasa vasorum in organization of thrombi in the cerebral arteries.
