A cerebral aneurysm is a bubble or blister on the wall of an artery. This bubble or blister is weaker than the rest of the vessel and can burst, leading to a subarachnoid hemorrhage. Aneurysms are very rare in children and develop as a patient ages. Risk factors for developing aneurysms include smoking and untreated hypertension.
Patient may have no symptoms from an aneurysm. Often they are discovered on a scan of the brain performed for some other reason, for example after a car accident in which a patient has hit his or her head. Some aneurysms may cause compression of nearby nerves and be detected as doctors work to discover the cause of the nerve dysfunction, or palsy. The most common presentation of an aneurysm, however, is an acute rupture. Patients classically complain of the sudden onset of the worst headache of their life.
An aneurysm can be detected on a CT-angiogram, MRA or digital subtraction angiogram. Diagnosis of subarachnoid hemorrhage can be achieved with CT scan, but sometimes might require a lumbar puncture.
- Digital Subtraction Angiography: Most aneurysms will require an angiogram to determine the exact size and shape of an aneurysm in order to determine which modality is best for treatment.
- Craniotomy: A craniotomy is an operation during which the skull is opened. A craniotomy for aneurysm involves removing the bone on the side of the head of the lesion and exposing the blood vessel with the aneurysm. A small clip, approximately 5mm, is placed on the aneurysm neck to prevent blood from entering. The Neurosurgical Hybrid Operating Suite at VCU offers surgeons the ability to perform angiography during the operation to ensure the aneurysm is treated and no important vessels have been inadvertently occluded.
The picture on the left is a middle cerebral artery bifurcation aneurysm under high magnification. The picture in the middle shows the application of an aneurysm clip across the neck of the aneurysm. The picture on the right illustrates complete occlusion of the aneurysm neck and preservation of the distal middle cerebral artery branches.
The picture on the left is a clipped internal carotid artery aneurysm. The picture on the right is the same aneurysm viewed during fluorescein dye angiography. The white dye does not enter the aneurysm, demonstrating complete occlusion, while all of the important blood vessels fill well.
- Coil embolization: If an aneurysm is the right size and shape, platinum coils can be placed inside the aneurysm until blood can no longer enter the aneurysm. The size and shape of aneurysms that are appropriate for this treatment has been greatly increased in the past few years by the advent of many stents and balloons that can assist in these procedures. Coils can compact over time and a patient needs to have follow-up angiograms after their coiling to ensure that their coils are not compacting, which might require further treatment.
In the first picture below, a microcatheter has been placed a PCOM artery aneurysm. In the picture on the right, the aneurysm has been successfully coiled and is no longer filling with contrast or blood.
- Liquid embolization: A small subset of aneurysms can be treated with liquid embolics. Filling an aneurysm with a thick, high viscosity liquid, like a spackle, allows for complete occlusion of the lumen and complete filling of irregular shapes. This therapy also theoretically decreases the risk of compaction
In the first pair of pictures on the left, a superior hypophyseal aneurysm and its irregular neck have been occluded with a liquid embolic. In the two pictures on the right, 3D angiography reveals complete obliteration of an ophthalmic artery aneurysm performed with a liquid embolic.
- An aneurysm does not need to be treated emergently. If an aneurysm has ruptured, however, it needs to be treated within the first day or so to prevent the aneurysm from bleeding again.
Brain aneurysm foundation: www.bafound.org/