Abstract
Angiography was performed in 712 patients by percutaneous injection of contrast medium into 1 carotid artery with the other digitally compressed. Collateral circulation was rated good in 69.3%, poor in 23.6% and absent in 7.1%. These percentages did not vary appreciably between vascular and non-vascular groups of patients or in the two age groups 0-49 years and 50-70 years.