Angiography is the study of blood vessels. Conventional catheter angiography is a technique that involves the injection of a positive contrast agent directly into the blood vessels through an indwelling vascular catheter (long thin hollow tube). These catheters are generally inserted percutaneously (via needles inserted through the skin).

Cerebral angiography using catheter technology involves accessing the arterial tree most often from the femoral artery (groin). Occasionally the brachial or axillary arteries may be used as the access point.

After the catheter is inserted into the desired arterial access point it is navigated into the vascular territory of interest. In cerebral angiography the catheters are most often placed into the cervical (neck) common carotid artery, internal carotid artery, external carotid artery, or vertebral artery. When nonselective injections are desired the catheters may be positioned in the innominate artery, subclavian artery, or even the aortic arch.

Once the catheter is in the desired position, a bolus injection of a positive contrast agent is performed during which X-rays are obtained for varying periods of time. This allows one to obtain images of the contrast agent as it progresses through the vascular tree from artery to capillary and then into the venous phase of circulation. Most often, the X-rays are obtained in fixed position. Different views of the blood vessels of interest can be obtained either by moving the patient relative to the X-ray tube or changing the position of the X-ray tube relative to a stationary subject.