Neuroradiology Teaching File

Arteriovenous Malformation

In the nonenhanced CT (on the left), there is an irregular area of high attenuation in the right parietal and occipital lobes.

Following intravenous contrast administration, multiple enhancing round and serpentine lesions are seen. The surrounding area of low attenuation most likely represents edema.

A pial arteriovenous malformation (AVM) is a congenital lesion that is composed of a complex network of dilated arteries and veins without a capillary bed. Although;they can be found anywhere, 85% are located in the cerebral hemispheres. They classically present as a cone shaped mass with its base at the brain surface and its apex extending toward the lateral ventricle.

Half of all pial AVMs present with hemorrhage, and 25% with seizures. It is clinically important because there is a 30% risk of death and a 25% risk of significant long-term morbidity with each hemorrhagic event. The cumulative risk of hemorrhage is 2 to 3% per year.

References: Osborn A: Intracranial Vascular malformations. In Diagnostic Neuroradiology, pp 284-301, St. Louis: Mosby, 1994.

Case prepared by Steven Lee, M.D. and Anthony L. Alcantara, M.D.

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