Cerebral angiography has been used since the 1930s and still remains the “gold standrad” for visualizing blood vessels of the brain. A small catheter is inserted in the groin, though which another thing catherter is passed over a flexible guidewire into each of the four arteries that carry blood to the brain. Then a dye containing iodine is injected and rapidly a sequence of xrays is obtained as a blood carries the dye though the brain vessles. A computer removes the shadow of the bone and tissue so that only the blood vessles can be seen in fine detail.
Using catheters and this technique, stroke and many problems of brain blood vessels can now be treated such as brain aneurysms, arteriovenous malformations or dural arteriovenous fistulas