What it means
Normally, small brain veins drain into larger veins in a regular pattern. In a developmental venous anomaly, a cluster of small veins drains into one larger collecting vein instead, like spokes meeting at a hub. After contrast, the pattern is often compared to the snake-haired head of Medusa (caput medusae). The veins still do their normal job of draining that part of the brain.
When it matters
It is one of the most common blood vessel variations seen on brain MRI, and it usually needs no treatment or follow-up. It is not removed, because that part of the brain relies on it for drainage. Doctors look more closely if there is a cavernous malformation next to it, a small cluster of fragile vessels that can bleed. Rarely, the collecting vein itself can clot.
Questions to ask your doctor
- Is there a cavernous malformation or any sign of bleeding next to it?
- Does this need any follow-up scan?
- Is it related to any symptoms I have, or purely incidental?
