Call 911 for a sudden severe headache, new weakness, speech or vision changes, loss of consciousness, or a first seizure.
Understanding a brain AVM
A brain arteriovenous malformation, or AVM, is an abnormal network in which arteries connect to veins through a vessel tangle called a nidus, bypassing the usual tiny capillaries. Some AVMs are found incidentally; others come to attention because of bleeding, seizures, headaches, or neurologic symptoms.
An AVM's location and blood-flow pattern matter as much as its size. Prior bleeding and the way blood drains away help inform the balance between observation and treatment.
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Advanced imaging: each test answers a different question
MRI shows the AVM's relationship to brain tissue and can reveal prior bleeding or surrounding changes. CTA provides another view of the blood vessels. Catheter cerebral angiography, also called digital subtraction angiography or DSA, maps the feeding arteries, nidus, and draining veins with detailed images of blood moving through them.
This dynamic vessel map can reveal features that are difficult to define on routine scans. It is particularly useful for planning a procedure or clarifying an uncertain vascular finding.
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From an angiogram to a treatment plan
The angiogram is interpreted together with your symptoms, MRI, and medical history. Your team considers which brain functions are nearby and what might happen with observation or treatment.
Options may include surveillance, microsurgical removal, catheter-based embolization, stereotactic radiosurgery, or a planned combination. Embolization blocks selected abnormal vessels and may support another treatment; in selected cases it can be a definitive approach. Treatment is not automatically safer than observation for every unruptured AVM, so individualized multidisciplinary review is important.
Questions that help make the decision clearer
Ask the team to show you the AVM on your images: Where is the nidus? Which arteries feed it? How do the veins drain? Has it bled? What is the goal of the proposed treatment, and might more than one stage be needed?
It is also reasonable to ask what the plan would be if you chose monitoring. Knowing the next imaging date and whom to contact about new symptoms makes follow-up more practical.
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Care continues after the procedure
Symptoms, imaging, and recovery guide follow-up. A smaller or partly treated AVM is not the same as confirmed complete closure. After radiosurgery, the abnormal vessels close gradually rather than immediately, so follow-up remains essential.
Bring all prior scan images and reports to each new consultation. Ask for a written plan covering activity, medicines, seizure management if needed, and the imaging used to assess the result.
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Common questions
Why do I need an angiogram if my MRI already shows an AVM?
MRI and angiography provide complementary information. DSA can map the precise feeding vessels, nidus, and venous drainage needed to assess the AVM and plan treatment.
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Does every AVM need embolization?
No. Observation, surgery, radiosurgery, embolization, and combinations each have a role. The recommendation depends on the anatomy, history, goals, and treatment risks.
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Your next step
Sources & further reading
This guide explains general care options. Your treating team will recommend an evaluation and treatment plan for your individual situation.