About Us

​Arteriovenous Malformation – or AVM – is a group of abnormal and poorly formed blood vessels (arteries and veins). They can be found anywhere in the body, and because they're so poorly formed, they have a higher rate of bleeding. Brain AVMs are of special concern because of the damage they cause when they bleed.

Though very rare, AVMs affect people of all ages and can be found in children. They're often discovered when they produce symptoms, such as headache or seizures.

Our team is made up of different health care practitioners who can diagnose a brain AVM and determine the best course of treatment. The first step is to get a visual picture of your brain, the blood vessels and the AVM. After the tests are completed, a member of the team will discuss with you and your family or caregiver your treatment options.​​​​​

Treatment Information

The goal of treatment is to prevent bleeding from the AVM. The bleeding may injure the surrounding brain resulting in a stroke, with possible permanent disability or even death. Given the complexity of some AVMs, some people can have combined treatments.

Treatment of AVM depends on a variety of factors: your age, your overall health, if you're having symptoms, and the size, location and blood vessels associated with the AVM. Some AVMs require a single treatment, while others are complicated in their location, shape or size and require more than one treatment type. The health care practitioner will go over your options during ​​your visit.

Sometimes AVMs can be tiny or not cause any symptoms. In that case, a periodic test, such as a CTA, may be recommended to check for any changes.

Endovascular Treatment: a neuroradiologist sends a small catheter or tube through an artery in the groin, and it finds its way to an AVM blood vessel. A kind of "glue" is released from the tube and enters the AVM. This substance instantly hardens, cutting off the blood supply – but it doesn't affect blood supply to the brain.

Surgical Treatment: a neurosurgeon operates and ties off the blood vessels that enter the AVM then removes it. This is a surgical procedure.

Radiation Treatment: this is also known as Stereotactic Radiosurgery. A narrow x-ray beam is focused on the AVM. The radiation used is quite safe and causes the AVM to close off.​

Surgical Treatment

​If you are interested in viewing the surgical treatment of an AVM, watch our 3 videos about the surgical clipping of an aneurysm.


There are a few different radiological tests that can provide the team with the necessary information needed. A health care practitioner may order more than one of these tests. Some can be completed by your family doctor before your first clinic visit.

How to Prepare

Your first appointment can take 2 hours or more. At this time we will review with you your test results and answer all questions that you have. We may also arrange to have some tests done during your clinic visit, such as a CT Scan. Other tests that you may require will be discussed with you during this time. Remember to bring your questions with you.

Follow-up appointments usually take 15 to 45 minutes. During this visit, we may discuss treatment results and your treatment options. You may meet various members of the team.

Learn more about what you can expect when you have a clinic appointment.​​

 Materials and Resources to Help You

Visit our health information section.​​

 Meet Our Team

Why some people develop AVMs is still unknown – but we know how to treat them, and we have the experts to care for you. They include:

  • Neurosurgeons
  • Neuroradiologists
  • Neurologists
  • Radiosurgeon
  • Radiation oncologists
  • Nurse Practitioner
  • Clinical Nurse Coordinator
  • Clinical Research Coordinator

Patient Care Coordinator: Gail Nixon


Chief of Neuroradiology
Dr. Timo Krings

Medical Imaging Radiologist
Dr. Robert Willinsky

Medical Imaging Radiologist
Dr. Richard Farb

Medical Imaging Radiologist
Dr. Ronit Agid



Clinic Support

  • Clinical Nurse Coordinator specializing in neuroradiology
  • Clinical Research Coordinator

Our Team Approach

Our clinical team is highly specialized, not only treating some of the most complex cases of AVMs in the country but pioneering treatments as well.

Through our partnership with UHN Foundation, we are proud to offer our patients modern, state-of-the-art equipment, which is necessary for both diagnosing and treating AVM.

Our team is affiliated with the University of Toronto's Faculty of Medicine, and we also work closely with the Hospital for Sick Children.

The AVM Clinic is part of the Neurointerventional Radiology Program and Neurosurgical Program at the Krembil Brain Institute at Toronto Western Hospital. Both of these programs are internationally recognized for their expertise and research. Since the early 1980s, specialists at the Krembil Brain Institute have pioneered image-guided technologies and developed surgical techniques that have revolutionized the field.

An integrated imaging and treatment environment is equipped with the most sophisticated 3-D angiography system, high-powered MRIs and now Gamma Knife radiosurgery. Here, neuro-interventional specialists and surgeons diagnose and treat some of the most complex neurovascular conditions including stroke, aneurysms and AVMs.​

Back to Top