Arteriovenous malformation. Coloured 3D frontal angiogram (blood vessel X-ray), with the healthy blood vessels of a 32-year-old patient overlaid on an image 2 years later showing an arteriovenous malformation (AVM). The cerebral arteries (orange) are shown with the cerebral veins (blue). The AVM is the red area at centre right. There is also a large drainage vein (light blue). This image was produced by Digital Subtraction Angiography (DSA), using a contrast medium to highlight the blood vessels.