Intracranial venous malformations


Intracranial venous malformations are veins in the brain that are unusually large. These larger veins aren't likely to cause symptoms or affect how the veins work.

Some people may have an intracranial venous malformation that is never diagnosed and never causes symptoms. Sometimes, they're found by accident when you have a brain imaging test for another condition.

Intracranial venous malformations usually don't require treatment.


Because you may not have symptoms with intracranial venous malformations, your health care provider might find that you have the condition during testing for other neurological problems.

You might have these imaging tests to diagnose other neurological conditions:

  • CT scan. A CT scan creates a series of X-rays to create detailed, cross-sectional images of your blood vessels and your brain. In some cases, dye is injected into a vein to assess the brain tissue or the blood vessels in greater detail (CT angiogram or CT venogram).
  • MRI. Magnetic and radio waves create detailed 3D images of your blood vessels and brain. In some cases a contrast dye is injected into a vein to look at the brain tissue in a different way, and to evaluate your blood vessels.
  • MRA. Magnetic resonance angiography is another type of MRI test that focuses on the arteries. An MRA shows how the blood flows through the blood vessels in the brain.
  • MRV. Magnetic resonance venogram is a type of MRI that focuses on the veins.


Doctors usually don't treat intracranial venous malformations because they rarely cause symptoms. If you have unrelated symptoms, such as headaches, your doctor might prescribe medications.

Rarely, people who have intracranial venous malformations have seizures or bleeding in the brain (brain hemorrhage). These are usually caused by other vascular malformations that can be found with a venous malformation. Doctors typically treat seizures with medications.

Some hemorrhages require surgery, but many hemorrhages can be treated with medical management and observation in a hospital.

Content From Mayo Clinic Updated: 08/08/2022
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