CNI Interventional Neuroradiology Service
Extracranial Carotid Atherosclerotic Disease
Extracranial Carotid Atherosclerotic Disease is a degenerative disease affecting the major arteries in the neck and head. Over time, this disease can lead to a build-up of plaques that severely narrow the passageways for blood to and within the brain, which can result in a stroke.
Angioplasty with Stenting
While carotid endarterectomy is the gold standard for the treatment of stroke and stroke-like symptoms due to atherosclerotic disease involving the carotid arteries, interventional neuroradiology offers a viable alternative for some patients. In the past fewyears, in fact, balloon angioplasty with stenting has become a preferred alternative procedure to surgery for many patients. In this procedure, a radiological catheter is threaded through the artery to the narrowed region. A stent is then placed within the artery, compressing the plaque that has narrowed the opening and thereby enlarging the space available for blood flow. Radiographic results of these procedures can often be spectacular, although, in contrast to carotid endarterectomy, this procedure has not yet conclusively proven to reduce the incidence of stroke. This procedure should only be attempted by an experienced cerebral vascular team with the input of a neurologist or neurosurgeon specializing in this area.
If treated within the first three hours of onset, the effects of a stroke often can be reversed using a proven front-line therapy called intravenous thrombolysis. This procedure involves the direct injection of the "clot busting" drug TPA. However, some patients fall outside the three-hour window or fail to respond to the drug. In such instances, another treatment alternative that is available is intra-arterial thrombolysis. In this procedure, a catheter is threaded into the cerebral arteries, and an angiogram is performed to reveal the exact location of the artery blockage. The catheter may be advanced into the clot to mechanically disrupt the clot as well as used for infusion of local TPA. Like intravenous thrombolysis, this can be a very effective means of reversing the effects of stroke for patients.
The photos below show a case of a right middle cerebral artery embolus that was treated with intra-arterial thrombolysis. The first slide is with the right middle cerebral artery occluded. The second is recanalization after IA TPA.
(1) The right middle cerebral artery is occluded.
(2) Recanalization after IA TPA.
A cerebral aneurysm is an aneurysm that develops within the brain. The aneurysm is a week spot that develops along the wall of an artery, often resembling a bulge or sac. As the aneurysm becomes enlarged, the bulge may compress surrounding nerves and tissue within the brain. This can result in nerve paralysis, headache, neck and upper back pain as well as nausea and vomiting. If the aneurysm ruptures, it can create an opening in the wall where blood can then enter into the brain, which may cause stroke or death.
Guglielmi Detachable Coil (GDC)
Introduced in the early 1990s, GDC is a technique that involves advancing a platinum coil into an aneurysm and then subsequently removing it by electrolysis. This procedure can only be used under certain circumstances and with the joint input of a neurovascular surgical team. This technique has proven particularly effective in preventing aneurysms from re-rupturing, at least in the short term. The ability of the GDC to prevent hemorrhage over many years, as has been demonstrated with aneurysm clipping, is still being determined. At CNI, each patient with an intracranial aneurysm is evaluated on an individual basis for GDC treatment. Learn more about aneurysms.
Patients suffering subarachnoid hemorrhage due to an aneurysm in many cases will undergo cerebral vasospasm. This results in a narrowing of the blood vessels in the brain as blood from the hemorrhage leaks into the brain cavity, irritating the large vessels at the base of the brain. This narrowing can reduce blood flow to that area of the brain, resulting in a complete stroke. Cerebral angioplasty has proven to be an effective and enduring treatment to reverse this sequence of events. With this procedure, a catheter is threaded through the vessels to the area of the vasospasm, and a balloon is inflated to reopen the artery and restore proper blood flow.
Arterial venous malformations are congenital lesions, which consist of blood flowing in via an artery and blood flowing out via a vein. The blood from the artery is oxygenated and has much more pressure than the blood flowing out through the veins, which carry deoxygenated blood back to the heart. The difference in the pressure between the blood in the arteries and the veins is typically managed by an intervening capillary bed. In an AVM, the capillary bed is replaced by a tangled mass of abnormal vessels. As a result, the veins carry pressurized and oxygenated blood away from the center, or nidus, of the AVM. This may result in seizures or hemorrhage, which may be life-threatening. Therefore, whenever possible, AVMs are removed either with surgery or with a combination of surgery and embolization to reduce blood.
Beginning in the late 1980's, the surgery on AVM's was facilitated by embolization using substances such as polyvinyl alcohol. As with brain tumors, this decreased the amount of bleeding seen at the time of surgery. However, since AVM's carry a particularly large amount of high pressure blood flow, the risk of blood loss can be prohibitive, rendering many large lesions inoperable. At CNI, Dr. Yakes has pioneered a new type of treatment that infuses the AVM with absolute ethyl alcohol. This has resulted in immediate sclerosis of the embolized vessels. In lesions in which he has been able to obtain a complete radiographic obliteration of the lesion, he has experienced at 69% cure rate. This type of treatment has not been duplicated elsewhere. Dr. Yakes has been invited to many destinations around the globe to educate others about this technique.
These procedures deliver precisely guided radiation beams from the image-guided capable linear accelerator to target malformations in a single, focused dose.
Vein of Galen Malformations
A special type of arterial venous malformation is called a Vein of Galen malformation. This is essentially an AVM or a fistula which drains into the Vein of Galen, which drains the deep structures of the brain. This type of lesion is seen in children.
At CNI, Dr. Yakes has treated many patients using a combination of transarterial and transvenous embolization, often with alcohol. He receives referrals from all over the United States for the treatment of this disease.
A fistula is a direct connection between an artery and a vein. Similar to the risks posed by arterial venous malformations, these can prove to be very dangerous for patients. In fact, with fistulas, the involved vein carries an even higher pressurized flow of blood than an AVM. Symptoms can result from a variety of means.
Carotid Cavernous Fistulas
This type of fistula often occurs as a result of trauma. Here, the carotid artery develops a direct connection with the cavernous sinus, a network of veins which surround the carotid artery and runs adjacent to the optic nerve. Patients who have carotid cavernous fistulas often go blind in the involved eye.
CNI’s Interventional Neuroradiology team has used a variety of techniques to treat carotid cavernous fistulas using only radiological means, thereby sparing patients the need for surgery.
Dural Arteriovenous Fistulas
A dural arterial venous fistula is an abnormal connection between an artery supplying blood to the scalp and skull and a specialized type of vein in the lining of the skull called a sinus. These often present later in life and usually have symptoms such as a whooshing sound in one ear. These lesions become particularly dangerous when high-pressure bloodflow from an artery enters a vein that normally drains an area of the brain. Since these veins are not accustomed to this type of high-pressure bloodflow, they may rupture. When this occurs, treatment may be taken to prevent subsequent hemorrhages. A combination of embolization, which slows blood flow to the involved vein, and surgery to redirect blood flow away from the involved vein may be recommended. However, an increasing number of patients have had these conditions resolved through the sole use of embolization, which is performed through endovascular means at CNI—eliminating the need for surgery altogether.