Atherosclerotic involvement of human intracranial arteries with special reference to intimal necrosis.

In a population sample aged 1-70 years where the cause of death was violent accident, the prevalence of intimal necrosis varied between 31.5 and 95.1% of cases in the basilar artery and between 10.5 and 59.6% of cases in the anterior cerebral arteries. In both basilar and anterior cerebral arteries the first areas of intimal necrosis occurred one or two decades earlier than the first fibromuscular plaques and the first fatty streaks. In each age group investigated the percentage of subjects with intimal necrosis appearing as an independent lesion was consistently greater than the percentage of subjects with atherosclerotic plaques, fatty streaks or incorporated microthrombi. Successive observations of similar topographic points placed in sequence according to age showed that many areas of intimal necrosis may represent the first stage in the development of atheromas or fibronecrotic plaques. On the other hand, using the same material and method, we were unable to reveal in intracranial arteries of subjects aged 31-70 years the conversion of fatty streaks to fibrous plaques.