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Contrasted CT scan is the preferred method to emergently evaluate patients with suspected liver injury. Liver lacerations are graded per the American Association for the Surgery of Trauma criteria according to their severity based on radiographic features. Grade I liver lacerations feature subcapsular hematomas measuring no greater than 1 cm at their greatest thickness, capsular avulsion, superficial parenchymal lacerations less than 1 cm deep, and isolated periportal blood tracking. Grade II injuries are characterized by parenchymal laceration 1–3 cm deep and parenchymal or subcapsular hematomas 1–3 cm thick. Those injuries demonstrating parenchymal laceration more than 3 cm deep, or subcapsular hematomas more than 3 cm in diameter are considered Grade III lacerations. Grade IV injuries are recognized by parenchymal or subcapsular hematoma more than 10 cm in diameter, lobar destruction, or devascularization of the liver, while Grade V injuries demonstrate global destruction of the liver parenchyma. Complete hepatic avulsions (Grade VI) may also occur.
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Subcapsular hematomas are generally identified between the liver capsule and the enhancing liver parenchyma on contrasted CT, and are most commonly located anterolateral to the right hepatic lobe. Liver parenchymal lacerations are seen as nonenhancing linear or jagged lesions typically observed in the periphery of the organ and may enlarge over time. Acute liver hemorrhage features areas of contrast extravasation on contrasted CT scan, while devascularized areas of the liver appear as unenhanced wedge-shaped regions extending toward the liver periphery.
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Clinical Implications
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The liver is quite vulnerable to blunt trauma and significant hepatic injuries may rapidly cause severe hemorrhagic shock and death. Contrasted CT scan may be very helpful in guiding therapy for patients who have sustained hepatic injury, both in identifying severe injury or active hemorrhage in need of immediate intervention as well as identifying those patients in whom nonoperative management may be appropriate. Hemodynamic stability is the most important factor when considering operative versus nonoperative management regardless of the radiographic features of the injury. Most liver lacerations in stable patients will resolve spontaneously without operative intervention. However, higher-grade liver injuries are associated with a greater incidence of significant vascular injuries and need immediate surgical consultation.
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