Testing & diagnosis for brain arteriovenous malformations in children

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Before proceeding to treatment, the care team will first conduct a variety of specific neurologic tests to assess the child’s brain function. Sometimes we recommend genetic testing if we suspect an inherited disorder. 

To help in choosing the best treatment, we carefully image the AVM and surrounding brain using noninvasive techniques, such as:


Magnetic resonance imaging (MRI) uses a strong magnetic field, radio waves and advanced computer processing to produce 2- and 3-dimensional images of the head, neck and brain. MRI is noninvasive and is critical in helping to evaluate AVMs that may not be assessed adequately with other techniques.

  • MRI uses no x-rays or radiation exposure of any kind.
  • Sometimes a contrast dye is injected through an IV during scanning to get a better image.
  • The child must lie still inside an MRI scanner—a large, tube-shaped magnet—sometimes requiring her to be sedated.
  • In response to the magnetic field and the radio waves of the scanner, water molecules in the body give off tiny pulses of energy. A computer constructs detailed images out of these pulses, showing the head, neck and brain anatomy. Read more.

CT angiography (CTA) uses the technology of a conventional CT scan, along with an injected special dye (known as contrast) to generate images of the blood vessels of the upper chest, neck and brain.

  • CTA generates images somewhat similar to those seen with cerebral catheter angiography, but since the dye is injected into a vein through a standard IV, rather than into an artery, CTA is less invasive.
  • During the test, the child must lie still on a table that slides slowly through a donut-shaped device. A computer constructs 3D images of the blood vessels from the CTA images.
  • Young children may need sedation to keep them still.

Magnetic resonance angiography (MRA) is a group of MRI-based imaging techniques used to evaluate blood vessels in the brain, head and neck. Unlike CT angiography, many MRA scans do not rely on contrast injected into the veins to generate images of the vessels, although contrast injections are sometimes used. Like conventional MRI, MRA avoids the use of x-rays.

Cerebral angiography, sometimes called cerebral arteriography or catheter angiography, can often provide additional valuable information about an AVM. It produces highly detailed images of the arteries and veins, using live x-rays.

  • The neuroradiologist or neurointerventionalist inserts a small needle into the femoral artery in the groin. Then, the specialist introduces a soft, thin wire that guides a catheter up to the arteries leading to the region containing the AVM.
  • A special dye, injected through the catheter, allows the radiologist to more clearly see the malformation or damage, as well as the pattern of arteries and veins surrounding it. The catheter also can be used to deliver treatments directly from within the vessels.
  • Cerebral angiography can take from 30 minutes to several hours, and in almost all children, it is performed under general anesthesia. After the angiogram, patients lie flat for four hours in the recovery room; during this time, with their parents close by, they can sleep, watch TV or use a handheld device.
  • We ask patients not to do vigorous exercise for several days after the procedure, although they can return to school as soon as they are ready to do so. Read more about angiograms.

The treatment team will provide advance instructions on how to prepare for these tests.

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