Overview: What is interventional neuroradiology?

Interventional Neuroradiology is a specialty primarily dedicated to the treatment of disorders of the blood vessels of the neck and brain (cerebrovascular disease) from inside the blood vessels (also called endovascular neurosurgery). Rapid advances in technology over the past fifteen years are responsible for the growth of this field. The two key technical components are the computer technology providing the images we use to guide catheters and other devices within the body, as well as advances in the devices themselves. 

A growing number of patients with diseases or disorders of the blood vessels of the neck, head and spine can be treated safely and effectively using devices within the blood vessels (endovascular). 

Common endovascular therapies include angioplasty (opening a narrowed artery with a balloon) and treatment of aneurysms (a balloon-like weakness in the wall of an artery) within the head. 

The Interventional Neuroradiology Service at Washington University offers a full range of endovascular therapies. Patients are evaluated in close consultation with colleagues in the Departments of Neurology and Neurological Surgery and the Division of Vascular Surgery. A multidisciplinary Vascular Conference, attended by endovascular specialists, vascular neurosurgeons, and stroke neurologists, is held each Tuesday morning for the purpose of deciding on the optimal treatment for each individual patient seen the preceding week.  This conference is one aspect of the Neurovascular Program at Washington University School of Medicine/Barnes Jewish Hospital.

Many vascular problems are complicated and require different combinations of medical, surgical, and endovascular treatment for the best outcome. Our goal is always to offer the patient the most effective treatment with the lowest risk. In some cases this may be no treatment at all. 

In addition to vascular disease, we offer other percutaneous (through small skin punctures) interventions related to the head, neck and nervous system. These include the injection of anesthetics for the relief of pain from nerve root inflammation, and the treatment of osteoporotic fractures of the spine with cement (vertebroplasty). 

For a consultation, please contact Tracy Dobbie, R.N., Nurse Coordinator for the Interventional Neuroradiology Service. EMAIL: dobbiet@mir.wustl.edu   PHONE: (314) 362-5580. 

Click HERE for photos (angiograms) of aneurysms, coils and stents, and for "before" and "after" PET images.

Nearly all of the techniques we specialize in are endovascular (from inside the blood vessel), employing catheters (tubes) or other devices placed through a catheter. The information at the bottom of the page regarding diagnostic angiography describes how these tubes are put in the vessels of interest. 

The endovascular techniques in which we specialize include the treatment of: 

• Aneurysms: Aneurysms are balloon-like weaknesses in the wall of an artery that may rupture (burst) if not treated. A ruptured aneurysm may be fatal, however, not all aneurysms need to be treated and not all aneurysms should be treated from within the blood vessels. We have several different options available for endovascular treatment. These include filling the aneurysm with soft platinum coils (case example) and blocking the artery from which the aneurysm arises with a variety of different devices. Over a third of patients with aneurysms of the arteries of the brain are treated from within the blood vessels at Barnes Jewish Hospital (over 120 patients with aneurysms were treated with coils last year).   An new option is a liquid agent (Onyx) currently in clinical trials in the United States (case example)
• Arteriovenous Malformations (AVMs): AVMs are abnormalities of the arteries and veins in which a direct connection, or short circuit, exists between the arteries and veins. Most are congenital, meaning that patients are born with this connection. Symptoms of headache, seizures, or bleeding do not usually appear until the 3rd or 4th decade of life. Rarely infants or small children are found to have an AVM. Surgery, radiation, and endovascular treatment are complementary techniques used for the treatment of these lesions. These abnormal vessels can be blocked with different materials injected through catheters (tubes) placed through the blood vessels into the lesion. 
• Carotid Cavernous Fistulas (CCFs): CCFs are an uncommon but unique subgroup of arteriovenous malformation. Most are acquired later in life than AVMs. They can be separated into direct connections between the carotid artery and the veins of the cavernous sinus (usually due to trauma) or indirect connections in which small arterial branches supply the veins. Both types can be treated very effectively with different endovascular devices 
• Cerebrovascular Stenosis: Atherosclerotic disease or hardening of the arteries can cause severe narrowing (stenosis) of the arteries of the neck and brain. Sometimes these narrowings may cause a stroke (permanent damage to the brain from lack of blood supply) or temporary symptoms of a stroke. This can be from particles of blood clot or plaque breaking free from the narrowing or from a reduction in the flow through the vessel because of the narrowing. In some patients, these narrowings can be opened using balloons inside the blood vessel (case example). Sometimes we place metal tubes (called stents) to help keep the vessel open. 
• Strokes: Most strokes are caused by blood clots lodging in the arteries of the brain. These blood clots can come from the heart or from atherosclerotic plaque in the vessels anywhere from the heart to the brain. If the blood clot blocks the artery for long enough, the brain cells ordinarily supplied by that artery will die from lack of oxygen and nutrients. In some patients, the blockage can be dissolved using powerful blood clot-dissolving drugs given right at the surface of the clot through small tubes. 
• Vascular Tumors: Most patients with vascular tumors of the brain or spine undergo embolization before surgery. Embolization refers to blockage of arterial supply using small particles through a small catheter (tube). The advantages of embolization is that blood loss during surgery can be reduced, making surgery safer, faster, and potentially allowing a more complete removal of the tumor. 
• Vasospasm: When an aneurysm ruptures, the bleeding over the surface of the brain sets in to motion a cascade of chemical events that results in severe narrowing of the arteries of the brain several days after the rupture. This narrowing may be so severe that medical treatment to keep enough flow through the vessel may fail. In these patients we can often open their arteries with direct administration of some different drugs and by using balloons to dilate the vessels. 
• Spinal Malformations: Arteriovenous malformations (AVMs) and vascular tumors often involve the spine or spinal cord. Endovascular techniques are often useful in as pre-operative or definitive treatment of these lesions. In addition, we also perform a variety of non-vascular procedures in the spine. These include biopsies, nerve root injections for pain relief, and diagnostic discograms.

The interventional neuroradiology service consists of three full-time staff, Drs. DeWitte T. Cross, III (Director), Colin P. Derdeyn (Program Director), and Christopher J. Moran, a nurse coordinator, Tracy Dobbie, R.N. and an endovascular surgical neuroradiology Fellow.

We perform a large volume of diagnostic cerebral angiography (>1000 per year) and  interventional procedures (>300 per year).  We train two endovascular surgical neuroradiology (intervenional neuroradiology) fellows per year.  Our program is ACGME-approved.

• Colin P. Derdeyn, MD
• DeWitte T. Cross III, MD
• Christopher J. Moran, MD

Purpose: Your doctor has requested that we perform a procedure called an angiogram to evaluate some of your blood vessels. The angiograms we perform in this section are to evaluate the blood vessels of the head, neck, brain, or spine. The angiogram you have performed will be specifically designed to answer the questions important for your care, so only certain blood vessels will be studied. These may include arteries such as the aorta, the carotid arteries, the vertebral arteries, the subclavian arteries, the spinal arteries, and the capillaries and veins of the head, neck, or spine, depending upon what parts of your circulatory or central nervous system are to be examined. The neuroradiologist who performs your examination will discuss the specific reasons for your procedure and what blood vessels we plan to study during the course of the examination. 

Method: This type of examination is called an "invasive procedure" because we must put a catheter (a long, narrow, flexible plastic tube) into a blood vessel in order to perform the procedure. Usually, this catheter is introduced through an artery in your groin and then directed to the vessels to be examined. Once the catheter is in position, a contrast agent ("dye") is injected which makes the selected blood vessels visible on X-ray. Let us know about any allergy you have to drugs, contrast agents, or dyes. Many images are taken during each injection using cameras above and beside you. The number of vessels studied and the number of injections performed will depend upon the questions we are trying to answer with the examination. The length of the examination will also vary from patient to patient, from 30 minutes to several hours, with the average length being about 1-1.5 hours. 

This procedure is most often performed using "local anesthesia" (numbing medication injected into the area before the needle and catheter are placed into the artery or vein) and intravenous sedation (medication injected into your IV line to make you comfortable and a little drowsy). At various points during the examination, you will be asked to hold still and to hold your breath while the pictures of the blood vessels are being recorded. Since motion will blur the images, it is important to remain as still as possible when you are asked. 

After the necessary blood vessels have been studied, the catheter will be removed, and in most cases, the radiologist will hold pressure over the puncture site for at least 10 minutes so that you will not bleed from the small hole the catheter created in the artery or vein. In selected cases, a special device may be used to close the hole in the artery. You will need to stay in bed following the procedure and keep your leg or arm (depending on where the catheter was inserted) straight and still in order to avoid bleeding. You will be observed for a short time after the procedure in our area, then go back to your room or to a treatment or recovery area, depending on your schedule for the remainder of the day. The nurses will be checking on you from time to time to be certain that you are not bleeding, but should you notice any bleeding, be certain to inform your nurse so that pressure can be re-applied to the puncture site. Side effects: You will initially feel some needle sticks where the catheter is to be placed. These are for the local anesthetic, which will sting some when first injected but will then make the area numb. You may feel the needle stick that punctures the artery and the initial placement of the catheter at its insertion site, but you will not feel the catheter inside your blood vessels and you should not feel any further discomfort with catheter movement after it is first inserted. When the contrast ("dye") is injected, you will probably feel a sensation of heat in the area of the body the blood vessel feeds, but only for a few seconds until the contrast washes out. The degree of heat felt varies from person to person and from blood vessel to blood vessel. It is not unusual to have some mild tenderness or bruising for a few days at the site the catheter was introduced. 

Potential risks: Just as with any invasive procedure, there are some risks involved in undergoing an angiographic procedure. 

The contrast agent ("dye") is eliminated from your body in a matter of hours through your kidneys. If you have poor kidney function (e.g. have an elevated creatinine level, require dialysis, or need a special renal diet) the contrast agent could injure your kidneys temporarily or permanently. If you have clotting abnormalities, you could bleed more than a normal amount from the hole in the artery or vein punctured for catheter introduction. Even with normal clotting functions, about 5% of people have enough bleeding under the skin to form a "hematoma", a collection of blood that could cause more extensive tenderness and bruising than normal. 

Less than 1% of people experience temporary neurologic deficits (weakness, numbness, or impaired speech or vision lasting from a few seconds for up to 24 hours) after the procedure. About 0.3% of people (3 in 1000) suffer permanent neurologic deficits (a stroke, which can range from minor to major) from diagnostic angiographic procedures such as these. Rarely, other complications may occur. For example, clots may form on catheters, the procedure may damage arteries, or severe allergic reactions to the contrast may cause breathing or circulatory problems. Fortunately, serious complications are rare, and this institution has the most experienced staff, the highest caseload, and best neuroangiographic facility in the region to perform these procedures. 

Alternatives: There is currently no ideal substitute for conventional angiography. Doppler ultrasound (sonography), CT scanning, CT angiography (CTA), MR scanning, and MR angiography (MRA) provide some useful information about blood vessels, but cannot provide the accuracy and resolution provided by catheter angiography. 

Information for patients scheduled for cerebral or spinal angiography last revised 10/25/99.

Stroke related Web Sites
American Stroke Association: Main page of the ASA, a new division of the American Heart Association dedicated to Stroke care 
Stroke Connection: Support groups for patients with stroke (maintained by the American Stroke Association) 

Washington University Sites
Research in Clinical Neuroscience: Descriptions of investigators in clinical neuroscience with links to the larger program (including basic science)
Neurovascular Program: Patient oriented site describing the complete range of clinical neurosurgical and endovascular services for patients with cerebrovascular diseases
Interventional Neuroradiology: Similar site to this one, maintained by Washington University School of Medicine
Internet Stroke Center: Comprehensive information relating to stroke treatment and clinical trials for patients and physicians
Emerging stroke therapies:  Recent lecture on the role of intra-arterial thrombolysis and carotid angioplasty and stenting with case illustrations