Diagnosis

If you experience a sudden, severe headache or other symptoms possibly related to a ruptured aneurysm, you'll be given a test or series of tests to determine whether you've had bleeding into the space between your brain and surrounding tissues (subarachnoid hemorrhage) or possibly another type of stroke.

If bleeding has occurred, your emergency care team will determine whether the cause is a ruptured aneurysm.

If you show symptoms of an unruptured brain aneurysm — such as pain behind the eye, changes in vision or double vision — you will also undergo some tests to identify the offending aneurysm.

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 presence of an aneurysm. This variation of the test is called CT angiography.

• Cerebrospinal fluid test. If you've had a subarachnoid hemorrhage, there will most 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 (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.

  A type of MRI that assesses the arteries in detail (MRI angiography) may detect the presence of an aneurysm.

• 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 detect an 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 family history of brain aneurysms, particularly if you have two first-degree relatives — your parents or siblings — with brain aneurysms
• A congenital disorder that increases your risk of a brain aneurysm