Brain aneurysms are potentially fatal and can be difficult to detect. Medical imagery such as MRIs and other tests involving contrast can help doctors determine the presence, location, and shape of brain aneurysms.

Brain aneurysms are spots that can form in your brain where weak or thin arteries have bulged out and filled with blood. While some brain aneurysms naturally resolve without symptoms, others can rupture, causing hemorrhaging in your brain.

The exact number of people who experience a brain aneurysm is unknown because brain aneurysms may not cause symptoms and may resolve before people notice them. However, it’s possible that brain aneurysms affect 1 in every 20–100 people.

This article will explain how medical imagery such as MRIs and other tests with contrast can help doctors find aneurysms and determine their size.

An MRI is a painless scan that uses strong magnetic fields to create detailed images of your brain. Doctors can use these images to determine the size, shape, and location of aneurysms.

Healthcare professionals may inject a contrast agent into your veins during the MRI process. It travels through your body to the arteries in your brain and allows the scan to capture more detailed images of the blood vessels. An MRI with or without contrast can help healthcare professionals identify a brain aneurysm.

Many people will not experience any symptoms from a brain aneurysm unless it ruptures or grows in a way that puts pressure on brain tissues and nerves.

When symptoms are present, they may include:

  • vision changes such as double vision or loss of vision
  • thunderclap headaches
  • weakness or numbness on one side of your face
  • pain around your eyes
  • trouble with speaking and balancing
  • short-term memory and concentration difficulties

Symptoms after a brain aneurysm has ruptured (known as a subarachnoid hemorrhage) can include:

  • nausea and vomiting
  • seizures or sudden loss of consciousness
  • pain or stiffness in your neck

These symptoms occur rarely and depend on the location of the aneurysm.

While an MRI is generally considered a highly accurate way to identify brain aneurysms, it may miss some brain aneurysms, especially smaller ones.

A MRI without contrast is one tool a doctor can use to determine whether an aneurysm is present or has ruptured.

Brain aneurysms may also be identified with other medical imagery, such as:

While healthcare professionals can use both MRIs and CT scans to detect brain aneurysms, they frequently use MRIs to search for unruptured aneurysms in the brain.

They often use CT scans with contrast to look for signs of a bleeding or ruptured aneurysm.

When considering whether to request an MRI or a CT scan, doctors will consider a variety of factors, including possible allergies to contrast agents or the presence of metal in the body, which would make performing an MRI unsafe.

Some smaller brain aneurysms may need only monitoring to ensure that they safely resolve and do not become bigger. Larger brain aneurysms or those in people with risk factors for a rupture may require:

  • Microvascular clipping: surgical insertion of a clip to cut off blood flow to the aneurysm
  • Platinum coil embolization: use of platinum wire in the artery to reduce blood flow to the aneurysm
  • Stents: flexible mesh tubes that can be inserted to divert blood flow away from the aneurysm

In addition to surgical procedures, people with brain aneurysms may need medications to reduce the risk of stroke and seizures. Physical, occupational, or speech therapy may also be recommended to address any abilities the aneurysm has affected.

About 25% of people who experience a ruptured aneurysm die within 24 hours, and 50% die within 3 months.

Factors that can affect the outlook for a person with a brain aneurysm include:

  • hypertension or other health issues
  • the size and location of the aneurysm
  • the presence of any hemorrhaging or brain damage

Brain aneurysms can be easily overlooked since people may not experience symptoms before they rupture. While many brain aneurysms resolve without treatment, the survival rate is low if an aneurysm ruptures.

Medical imaging scans such as MRIs are important tools for detecting and monitoring brain aneurysms. If you experience symptoms of a brain aneurysm, it’s important to consult a healthcare professional as quickly as possible.