Liver trauma and transection of the inferior vena cava. Sentinel contrast sign and hepatic perivenous tracking.

CT of a child with severe liver trauma due to a seat belt injury demonstrated avulsion of a portion of the lateral segment of the left lobe of the liver. The location of nondependent extravasated contrast material aided in identification of the visceral fracture site (the sentinel contrast sign). Associated transection of the inferior vena cava was evidenced by hypoattenuating zones adjacent to all the major hepatic veins and vena cava (hepatic perivenous tracking). Recognition of these two signs is important so that the radiologist can help the surgeon select the optimal operative approach.