Cerebral (Brain) Angiogram

What is it?

Catheter brain angiogram is a minimally invasive diagnostic procedure where especially detailed images of brain vessels are obtained. The level of detail in being able to see very small arteries and veins, as well as the ability to look at blood flow through the brain in real time, constitute some advantages of the cerebral angiogram over non-invasive techniques such as MRA and CTA. Tremendous advances in modern CTA and MRI/MRA imaging allow, in most cases, for sufficient information to be obtained without the need for a Catheter Brain Angiogram. However, in some select instances unanswered questions remain, and a catheter angiogram is requested.

What are the common indications (reasons) for doing Cerebral Angiography

The more common reasons we are asked to do an angiogram are:

  • Brain Arteriovenous Malformation: an abnormal connection between arteries and veins, where it is especially important to understand how blood flows through the AVM and how it affects the adjacent brain
  • Dural Arteriovenous Fistula: an abnormal connection between arteries and veins in the tissues which surround the brain, and can produce a variety of symptoms from pulsatile tinnitus to hemorrhage and epilepsy. The ability of MRA and CTA to visualize dural fistulas remains limited
  • Cerebral Aneurysm: Most aneurysms are well-seen on CTA and MRA, however some details can only be answered by a catheter angiogram
  • Acute Stroke: patients with blockages of large arteries in the brain, leading to an acute stroke, can sometimes dramatically improve if the occluding clot (thrombus) is removed or dissolved. A cerebral angiogram is part of the intra-arterial treatment of this condition
  • Suspected Cerebral Vasculitis (CNS vasculitis): Inflammation of the wall of small brain arteries can lead to peculiar strokes and brain dysfunction. Patients with connective tissues diseases such as Systemic Lupus Erythematosus (SLE) or inflammatory disorders such as Wegener’s Granulomatosis, are more likely to develop CNS vasculitis than others. The affected arteries are often too small to see on either MRA or CTA, and a catheter angiogram is requested to evaluate them
  • Atherosclerotic / Occlusive disease: Sometimes an angiogram is requested to evaluate patients with narrowed or occluded (closed) arteries in the head and / or neck, to see how well other arteries can compensate for the deficiencies

There are many other, less common indications, such as Cerebral Activation (WADA) testing, vessel dissection, venous thrombosis, pulsatile tinnitus, and others which are individually discussed with the patient before the angiogram.

How is an angiogram performed?

The procedure is performed awake or under mild sedation in most adults. Pediatric patients require deeper sedation. A catheter (long, skinny piece of hollow plastic tubing) is inserted into an artery in the upper leg after local sedation (Lidocaine most often) is used to numb the area. The catheter is navigated under X-rays into the aorta and from there into the arteries which supply blood to the brain. A contrast dye (nonionic contrast) which can be seen on x-ray cameras is then injected through the catheter, and the flow of this dye through the vessels of the brain is recorded as a kind of movie. The catheter is then re-positioned into another artery, and more images are taken, until all required information is obtained. During injections of the dye, the patients may feel contrast flow as sensations of warmth or different taste. After the angiogram is concluded, the catheter is removed and the small opening made to introduce it is closed by manual compression or by a special closure device. The patient then remains under observation in the hospital for a period of about 6 hours. Most patients arrive in the morning and leave the hospital in the afternoon. We advise that patients do not eat or drink for a variable length of time before the angiogram; most patients are able to eat and drink soon after the procedure.

Are there risks to an angiogram?

Any medical procedure has risks. The angiogram is considered a minimally invasive study. The most concerning risk, though very small, is a possibility of a stroke – damage of arteries supplying the brain during the procedure, or formation of thrombi (clots) around or within the catheter can cause a stroke. The risk of stroke from an angiogram depends on many factors, such as the patient’s health in general and vascular health in particular, the experience of the physician performing the angiogram, and the vessels which need to be imaged, among others. Patients are encouraged to inquire about institution-specific risks of whatever procedure is being performed.

Other risks, perhaps not so disturbing but more common, include groin hematomas (bleeding around the site of catheter insertion), and allergic and other reactions to the dye (rash, migraine headaches, among many others). On the other hand, the diseases with which the angiogram is concerned also have certain hazards, which usually far outweigh the risks of the angiogram. Unless the procedure is a life-threatening emergency or the patient is unable to participate (for example, if the patient is having a stroke), an individualized discussion of risks and benefits between the patient, family/friends, and physician takes place.

When can I expect results?

Usually, the results are discussed with the patient, family, and/or others the patient has designated immediately after conclusion of the procedure. A decision on management can be arrived at immediately or may require multidisciplinary physician consideration, depending on the specific issue at hand.


We perform a wealth of angiograms for many different indications, in patients of neonatal age and onward, under all circumstances of overall health. While some issues and concerns are common to all circumstances, most questions have specific relevance in context of the individual patient. If you are scheduled for an angiogram, wish to refer a patient, or have questions/concerns, please contact the staff of The Bernard and Irene Schwartz Interventional Neuroradiology Center at 212-263-6008