Division of Interventional Neuroradiology


INTRACRANIAL ANEURYSMS


Table of Contents (click to jump to sections)
What is an aneurysm?
How common are aneurysms?
Are aneurysms hereditary?
What is the risk of bleeding from aneurysms?
What are symptoms of an aneurysm?
How is an aneurysm diagnosed?
How are aneurysms treated?
DINR statistics on therapeutic management of intracranial aneurysms


Aneurysm image, an abnormal saccular or diffuse dilatation of an artery.
Figure 1. An aneurysm.


What is an aneurysm?

An aneurysm is an abnormal saccular or diffuse dilatation of an artery (Figure 1).

Click on the links below to play short, illustrative video clips.
Video 1 - Aneurysm     Video 2     Aneurysm 3 Video    
Aneurysm 1 Aneurysm 2 Aneurysm 3


How common are aneurysms?

Its overall prevalence is about 4-5% in the general population. There is a clear female preponderance ranging from 54 -61%. Approximately 20-30% of patients will have multiple aneurysms.

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Are aneurysms hereditary?

The recommendation regarding screening for aneurysms is that if two or more first degree relatives have an aneurysm, one should be screened. The best screening tool is non-invasive imaging with MRI or with CT angiogram.

In general, aneurysms rarely occur in more than one family member. When aneurysms are present in more than one family member a known hereditary syndrome is often present, such as polycystic kidney disease, Ehler-Danlos syndrome, pseudxanthoma elasticum.

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What is the risk of bleeding from aneurysms?

For an aneurysm that has not bled, the risk of rupture appears to be related to its size and location. With respect to size, aneurysms smaller than 7 mm have a benign natural history. Larger aneurysms have greater risk of bleeding. The location of the aneurysm is also important. Even if an aneurysm is less than 7mm, in certain locations in the brain, it may have a high risk of bleeding. In deciding on treatment, both factors are taken into consideration in the evaluation process.

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What are symptoms of an aneurysm?

If an aneurysm has not bled, there may not be any symptoms and the first time the patient learns that they have an aneurysm is when they have a bleed.

If an aneurysm bleeds the symptoms are as follows: sudden severe headaches, neck stiffness, nausea and vomiting. Sometimes patients may even have stroke like symptoms such as weakness, double vision, blindness in part of the vision, confusion or loss of consciousness.

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How is an aneurysm diagnosed?

An aneurysm that has not bled is typically discovered on a CT or MRI scan (Figure 2) that is being done for evaluation of problems that may be unrelated to the aneurysm. If an aneurysm is discovered in this manner it is referred to as an 'incidental aneurysm.'


Figure 2. MRI of 'incidental' aneurysms.
Figure 2. MRI of 'incidental' aneurysms.

If an aneurysm bleeds, then CT scan is typically done to confirm the bleed and for evaluation of the aneurysm the best diagnostic tool available currently is a catheter angiogram.

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How are aneurysms treated?

The modern treatment of aneurysms include classical surgical clipping of the aneurysm or coiling of it (Figures 3, 4, and 5). The selection of therapy depends primarily upon the aneurysm size and location.

Rupture Before
Rupture before, 3-D
After Treatmeent - Bleeding is arrested using detachable coil
After Treatment 3-D View
Figure 5. Detachable coil filling aneurysm.
Figure 3. Before Treatment: Hemorrhagic stroke from ruptured intracranial aneurysm. Figure 4. After Treatment: Bleeding is arrested using detachable coil. Figure 5. Detachable coil filling aneurysm.

Endovascular occlusion of aneurysms includes the use of detachable coils. This is a angiographic procedure where a small soft catheter is introduced into the blood vessel from the leg artery. From there the catheter is carefully threaded up into the brain and the tip of the catheter is placed in the aneurysm (figure 6). Then through the catheter small soft coils are introduced into the aneurysm to block it completely (figure 7).
Image of catheter being  carefully threaded up into the brain. Endovascular occlusion of aneurysms includes the use of detachable coils.
Figure 6. The catheter is carefully threaded up into the brain. Figure 7. Endovascular occlusion of aneurysms includes the use of detachable coils.

This technique of treating aneurysms with coils was invented at UCLA in 1990 and the first patient in the world was treated here in 1991. Since then, more than 1300 patients have been treated with this technique at UCLA.

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DINR statistics on therapeutic management of intracranial aneurysms

First aneurysm ever treated with GDC coils in March 6, 1990.

Figures updated to June 20, 2012.

PATIENTS 1606    
ANEURYSMS 1766    
       
LOCATION SUPRATENTORIAL 1171 72%
  INFRATENTORIAL 595 28%
       
CLINICAL PRESENTATION RUPTURED 825 46.7%
  UNRUPTURED 941 53.3%
       
GOOD CLINICAL OUTCOME RUPTURED 607/825 73.5%
  INCIDENTAL 571/584 97%
       
TECHNICAL COMPLICATIONS AN. PERFORATION 40/1766 2.3%
  CEREBRAL EMBOLIZATION 36/1766 2%
       
CLINICAL COMPLICATIONS   87/1606 5.4%
       
DEATH RUPTURED 47/607 7.74%
  INCIDENTAL 5/584 0.8%
       

Four hundred and twenty patients harboring small incidental aneurysms are being followed up with CTA every 6 months/year looking for aneurysm anatomical and/or morphological changes as sign of impending rupture.

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