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Brain aneurysm

Diagnosis of brain aneurysm

Since many brain aneurysms don’t show symptoms, it is common for doctors to find them accidentally during an evaluation for another medical condition.

If you do have symptoms of a cerebral aneurysm, your doctor will likely use some combination of a CT scan, MRI, and spinal tap to diagnose you.

Cerebral aneurysms are typically diagnosed following symptoms, using a CT scan. A CT scan will identify over 90% of ruptured aneurysms if conducted within 72 hours of rupture.

Your doctor might also use MRI imaging to identify a possible aneurysm rupture or a spinal tap to look for evidence of bleeding in the cerebrospinal fluid.  

Because ruptured aneurysms share many symptoms with other conditions like meningitis, migraines, tumors, and strokes, your doctor may also conduct additional tests to rule these conditions out.


Not all brain aneurysms require treatment; many never show symptoms at all.

Treatment and prevention options depend on the aneurysm size, type, and location. If a brain aneurysm is small and not causing problems, your doctor may recommend monitoring it for changes.

In other cases, your doctor may recommend surgery to prevent the aneurysm from rupturing. Each case is unique, so you should talk with your doctor about all of your treatment options.

Potential surgical approaches to treat brain aneurysms include:

  • Clipping: This is when a surgeon opens the skull, identifies the aneurysm, and “clips” it, sealing off the vessel so that no further blood can leak into the balloon.
  • Coiling: This is when a surgeon uses an angiogram to thread a small tube through the artery without opening the skull. Once the aneurysm is reached, the surgeon can then fill the balloon to prevent further blood from entering.

A ruptured brain aneurysm is a medical emergency. When an aneurysm bursts, it can bleed into the brain, causing a hemorrhagic stroke. It can also bleed into the space around the brain, causing a subarachnoid hemorrhage.

Both are severe conditions that can lead to permanent brain or nerve damage, or even death. Treatment at Dignity Health will aim to stop bleeding and prevent further brain damage.


If an aneurysm is present but does not rupture, it may not cause any medical issues at all.

Almost half of the people who suffer a ruptured brain aneurysm do not survive. According to the NIH, about one-quarter will not survive the first 24 hours following a rupture.

Blood vessel spasms are common following an aneurysm and can lead to strokes and other complications. Another quarter of aneurysm rupture patients will die within the six months following a rupture due to complications from the rupture, surgical complications, or resulting neurological problems. 

Of those who do survive for longer than six months after a rupture, more than half experience permanent brain damage. 

However, many people experience milder outcomes and recover with little or no neurological disability. Generally speaking, the faster the patient receives emergency care, the better the result.

After an aneurysm bursts, factors that can affect recovery include:

  • Age and general health
  • Whether there were previous neurological conditions present
  • The size, location, and cause of the aneurysm rupture
  • How quickly the aneurysm was treated
  • Whether the aneurysm can successfully be treated
  • How much bleeding occurs before it can be stopped

The information contained in this article is meant for educational purposes only and should not replace advice from your healthcare provider.

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