Sentinel clot sign

Last revised by Dr Mohamed Saber on 08 May 2021

The sentinel clot sign is a useful CT finding for the evaluation of probable anatomic sites of hemorrhage.

On CT, acute clotted hemorrhage typically has high attenuation (45 to 70 HU), whereas surrounding areas of acute non-clotted hemorrhage or more chronic hemorrhage have either lower attenuation (30 to 45 HU) or fluid attenuation (0 to 10 HU).  

This is the basis for the sentinel clot sign, areas of higher attenuation are likely to represent more acute clotted hemorrhage, and are therefore more likely to indicate the anatomic sites of hemorrhage.

Radiographic features


On CT clotted blood has increased attenuation value as compared to non clotted blood. It is primarily used in patients of trauma and circumstances of non-traumatic hemoperitoneum 4.

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Cases and figures

  • Case 1: ruptured ectopic pregnancy
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  • Case 2: mesenteric injury
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  • Case 3: active mediastinal bleeding
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  • Case 4: ruptured ovarian hemorrhagic cyst
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