Localized clotted blood as evidence of visceral trauma on CT: the sentinel clot sign

We retrospectively reviewed the CT scans of 116 patients with abdominal trauma who had visceral injuries to determine if identification on CT of focal high-density clotted blood (a "sentinel clot") was an accurate sign of injury to an adjacent organ. The sentinel clot sign was sensitive, present in 101 (84%) of 120 visceral injuries with only three false-positive cases. Whereas CT visualized the visceral injury itself in 86% of cases, the sentinel clot was the only clue as to the source of hemorrhage in 14% of the cases. Splenic and bowel/mesenteric injuries were frequently subtle, and the focal clot helped to focus attention on the traumatic lesion. In 9% of splenic trauma cases and 32% of bowel/mesenteric injuries, the sentinel clot was the only positive finding. Localized clot is a frequent and accurate sign of injury to an adjacent organ. By facilitating diagnosis of trauma to a specific organ, it may influence the management decision of surgical vs conservative therapy.