SWIRL SIGN A PREDICTOR OF HEMATOMA EXPANSION

Swirl sign represents extravasation of the blood which is fresh and active (acute ). The unclotted blood appears lower in attenuation compared to the clotted blood , thus forming layers of hyper and hypoattenuations , called as swirl sign . Thus its a predictor of hematoma expansion.

The above figure demonstrates swirl sign followed by tripling the linear size of the hematoma after 6 hours.