Tests and diagnosis

By Mayo Clinic Staff

If you have a sudden, severe headache or other symptoms possibly related to a ruptured aneurysm, you will have a test or series of tests to determine if you have had bleeding into the space between your brain and surrounding tissues (subarachnoid hemorrhage) or another type of stroke. If bleeding has occurred, then your emergency care team will determine if a ruptured aneurysm is the cause.

If you have symptoms of an unruptured brain aneurysm — such as pain behind the eye, changes in vision and paralysis on one side of the face — you will likely have the same tests.

Diagnostic tests include:

  • Computerized tomography (CT). A CT scan, a specialized X-ray exam, is usually the first test used to determine if you have bleeding in the brain. The test produces images that are 2-D "slices" of the brain. With this test, you may also receive an injection of a dye that makes it easier to observe blood flow in the brain and may indicate the site of a ruptured aneurysm. This variation of the test is called CT angiography.
  • Cerebrospinal fluid test. If you've had a subarachnoid hemorrhage, there will mostly likely be red blood cells in the fluid surrounding your brain and spine (cerebrospinal fluid). Your doctor will order a test of the cerebrospinal fluid if you have symptoms of a ruptured aneurysm, but a CT scan hasn't shown evidence of bleeding. The procedure to draw cerebrospinal fluid from your back with a needle is called a lumbar puncture or spinal tap.
  • Magnetic resonance imaging (MRI). An MRI uses a magnetic field and radio waves to create detailed images of the brain, either 2-D slices or 3-D images. The use of a dye (MRI angiography) can enhance images of blood vessels and the site of a ruptured aneurysm. This imaging test may provide a clearer picture than a CT scan.
  • Cerebral angiogram. During this procedure, also called a cerebral arteriogram, your doctor inserts a thin, flexible tube (catheter) into a large artery — usually in your groin — and threads it past your heart to the arteries in your brain. A special dye injected into the catheter travels to arteries throughout your brain. A series of X-ray images can then reveal details about the conditions of your arteries and the site of a ruptured aneurysm. This test is more invasive than others and is usually used when other diagnostic tests don't provide enough information.

Screening for brain aneurysms

The use of imaging tests to screen for unruptured brain aneurysms is generally not recommended. However, you may want to discuss with your doctor the potential benefit of a screening test if you have:

  • A parent or sibling who has had a ruptured brain aneurysm, particularly if you have two such first-degree family members with brain aneurysms
  • A congenital disorder that increases your risk of a brain aneurysm
May. 24, 2011