as 1927 Egas Moniz, teacher of neurology in Lisbon and Nobel Prize for Physiology or Medicine in 1949, placed cerebral angiography, Whereby both normal and abnormal blood vessels in and around the brain could be visualized with great accuracy. In its early days this method likewise carried both immediate and long term risks, Many of them referable to deleterious effects of good contrast substances that were used for injection into the circulation. Techniques have become very refined in the past few decades, With one in 200 patients or less experiencing ischemic sequelae from the procedure