|
Christopher Zylak, MD Director of Neurointerventional Radiology
Aneurysms
What is an aneurysm?
A cerebral aneurysm is an abnormal swelling or ballooning of a brain artery. It is usually due to weakness in the wall of the vessel. This condition is either present at birth (congenital) or acquired. Medical problems like high blood pressure contribute to the formation of aneurysms.
 |
 |
| Aneurysm |
Rupture |
How do you acquire an aneurysm?
Cerebral aneurysms were once thought to be a congenital (from birth) abnormality. While this may be true in some cases, studies have shown that aneurysms can be caused by a number of factors. Very often aneurysms develop from a weakening in the structural layer of an artery which allows the growth of an aneurysm. High blood pressure (hypertension) and fat buildup in the artery wall (atherosclerosis) can promote aneurysm growth and rupture. Certain infections in the blood can cause a type of aneurysm called a mycotic aneurysm. Although some of the factors that cause aneurysms are understood, it is usually not possible to determine a single cause.
How often does aneurysm occur?
Aneurysms are among the top ten causes of death in white males age 55 and over. By about age 80, over 5% of white males will have developed an aneurysm. Aneurysms occur less frequently in white women, and they are relatively uncommon in African Americans of both sexes.
How is an aneurysm detected and diagnosed?
Aneurysms can be discovered in several ways. Most often the swollen wall of aneurysms is weaker than the normal artery wall and a rupture occurs. When a cerebral (brain) aneurysm ruptures, it typically bleeds into the area surrounding the brain (subarachnoid space) to cause a subarachnoid hemorrhage (SAH). Unruptured cerebral aneurysms are identified when they cause neurological symptoms. These depend on the location and size of the aneurysm but may include headaches, double vision, and trouble with walking. Sometimes, aneurysms are found incidentally when a head CT or MRI scan, or angiogram is performed for some other health reason.
The diagnosis of a cerebral aneurysm is usually confirmed with an angiogram, an x-ray of the head using an injection of a contrast agent (mainly water and iodine salts) into the blood vessels. Recent advancements in CT and MRI scanning help these techniques to diagnose aneurysms, but an angiogram usually provides the most detail of an aneurysm's size and location and remains the "gold standard" in diagnosing a cerebral aneurysm.
 |
| 3-D Rotational angiogram |
 |
| Cerebral angiogram |
What are the treatment options?
The goal of treatment, for unruptured aneurysm, is to prevent aneurysm rupture or growth. For ruptured aneurysms, the goal of treatment is to prevent further bleeding ("rebleeding") and to prevent or limit vasospasm (abnormal constriction of the arteries). Both surgical and non-surgical treatments are available and should be discussed with your interventional neuroradiologist or neurosurgeon.
Endovascular treatments for cerebral aneurysms have developed in recent years and can provide partial or complete treatment of many aneurysms. One such treatment involves threading a catheter from an artery in the leg up to the aneurysm and under x-ray guidance placing a synthetic coil into the aneurysm (coiling). Endovascular techniques are still developing but have shown utility in treating certain aneurysms which are not suited to surgery.
| Stages of GDC Deployment into an aneurysm |
 |
| Types of GDC Coils |
 |
Surgical clipping provides direct and effective treatment for most aneurysms as well. In particular, those aneurysms that are not treatable with coiling are then treated in the following manner. The skull is surgically opened (craniotomy) and a small titanium clip is placed across the base of the aneurysm. In doing so, the weak abnormal aneurysm wall is protected from blood flow; thus, the risk of rupture is eliminated. At the same time, the normal artery wall is reconstructed to maintain blood flow to the brain.
The type of operation is determined by the size and location of the aneurysm(s). The timing of surgery is based on many factors, but following aneurysm rupture, early surgery is favored to prevent or limit vasospasm.
|
|
|
|
