Intraparenchymal &/or subcapsular hematoma
Injury to bare area of liver may result in retroperitoneal, not intraperitoneal, bleeding
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Best imaging tool: MDCT in hemodynamically stable patients
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CT protocol advice: Rapid bolus of contrast; include lung bases and pelvis
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Angiography to localize active hemorrhage and embolization to control it
TOP DIFFERENTIAL DIAGNOSES
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Spontaneous hemorrhage (coagulopathy)
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Bleeding hepatic tumor (e.g., hepatocellular carcinoma or adenoma)
PATHOLOGY
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Blunt trauma is most common cause of hepatic injury
CLINICAL ISSUES
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Clinical profile: Patient with history of motor vehicle accident, right upper quadrant tenderness, guarding, and hypotension
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Liver is 2nd most frequently injured solid intraabdominal organ after spleen
DIAGNOSTIC CHECKLIST
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CT evidence of
active extravasation
Intra- or extrahepatic collection,
i sodense with vessels
Usually indicates
need for embolization or surgery, regardless of grade of injury
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Laceration of left hepatic lobe is often associated with bowel and pancreatic injury
TERMINOLOGY
Definitions
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Liver or hepatic injury
IMAGING
General Features
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Best diagnostic clue
CT evidence of irregular parenchymal lesions with intra- and perihepatic hemorrhage
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Location
Right lobe (75%), left lobe (25%)
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Intraparenchymal &/or subcapsular hematoma
CT Findings
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Lacerations: Simple or stellate (often parallel to portal/hepatic vein branches)
Simple: Hypodense, solitary, linear laceration
Stellate: Hypodense, branching, linear lacerations
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Parenchymal and subcapsular hematomas (lentiform configuration)
Unclotted blood (35-45 HU) soon after injury
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NECT: May be hyperdense to normal liver
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CECT: Hypodense to enhancing normal liver tissue
Clotted blood (60-90 HU)
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Hyperdense to unclotted blood and normal liver
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May be hyperdense to unenhanced liver
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“Sentinel clot” helps to localize source of bleeding
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Active hemorrhage or pseudoaneurysm
CECT:
Active hemorrhage
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Isodense to enhanced vessels
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Extravasated contrast materia l (85-350 HU) surrounding low-attenuation clot
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Hemoperitoneum: Perihepatic and peritoneal recess blood collections
Injury to bare area of liver may result in retroperitoneal, not intraperitoneal, bleeding
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Periportal tracking: Linear, focal, or diffuse periportal zones of decreased HU
Due to dissecting blood, bile, or dilated periportal lymphatics
Differential diagnosis: Overhydration; check for distended inferior vena cava (IVC)
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Increased venous pressure and transudation
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Areas of infarction
Small or large areas of low attenuation
Usually wedge-shaped; segmental or lobar
Intrahepatic/subcapsular gas (due to hepatic necrosis)
May be due to trauma itself or iatrogenic (following surgery or coil embolization for active bleeding)
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CT diagnosis of liver trauma
Accuracy (96%), sensitivity (∼ 100%), specificity (94%)
MR Findings
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T1WI and T2WI
Varied signal intensity depending on degree/age of hemorrhage or infarct
Ultrasonographic Findings
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Grayscale ultrasound
Subcapsular hematoma: Lentiform or curvilinear fluid collection
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After 24 hours: Echogenic
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1-4 weeks: Internal echoes, septations develop within hematoma
Intraparenchymal hematoma
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Rounded echogenic or hypoechoic foci
Bilomas
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Rounded/ellipsoid, anechoic, loculated structures
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Well-defined sharp margins close to bile ducts
Parenchymal tears
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Abnormal echotexture relative to normal liver