Abstract
It has frequently been suggested that in Western Countries, cerebral infarction caused by the occlusive or stenotic lesions of the extracranial cerebral arteries, is more common than that by the intracranial. To investigate the extracranial cerebral arteriosclerosis of Japanese, the atherosclerotic process were assessed in the entire carotid vertebral systems, and compared with the atherosclerosis of circle of Willis, in a series of 84 autopsied cases (23 in cerebral infarcts 61 in controls, unselected in regard to pathological diagnosis), over the 40 years old.
Initially, the vessels were cut transversely for the evaluation of stenotic lesions, and when the lumen was occluded or severely narrowed, they were prepared to paraffin sections to facilitate more accurate estimation of the luminal narrowing, and then the degree and severity of atherosclerosis on the entire surface of the vessels were gradded macroscopically by Gore's method,
Results obtained are as follows;
1) The degree of atherosclerosis of the common carotid calculated by narrowing index, revealed the highest, and then in order the internal carotid, the vertebral arteries. Atherosclerotic index of the three vessels showed the same trends.
2) The occluded or severely narrowed lesions of the extracranial cerebral arteries were found more frequently in the cases of cerebral infarcts than in controls, but the intracranial cerebral atherosclerosis was more severe in the former than in the latter.
3) Compared the atherosclerosis of the extracranial with that of the intracranial by narrowing index, the prominent lesions were found in the latter.
4) Microscopically, the most frequent findings of the narrowed lesions were the aggregation of amorphous materials in the intimal deep layers at the bifurcation of the vessels, and the calcification at the carotid siphon.
It seems attributable that in Japan, the occluded or severely narrowed lesions of the extracranial cerebral arteries may not play any significant roles on the incidence of cerebral infarction, as in Western Countries.
