Abdominal Trauma Imaging

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Abdominal Trauma Imaging: Initial Scan - FAST & Furious

  • FAST: Focused Assessment with Sonography for Trauma.
  • Rapid, portable, non-invasive bedside ultrasound. Detects free intraperitoneal fluid (hemoperitoneum) & pericardial effusion.
  • Key role: Rapid triage of hemodynamically unstable patients to OR vs. further imaging.
  • Key Views:
    • Perihepatic (Morison's Pouch)
    • Perisplenic
    • Pelvic (Pouch of Douglas/Rectovesical)
    • Pericardial (Subxiphoid)
  • eFAST (Extended FAST): Adds bilateral anterior thoracic views to detect pneumothorax or hemothorax.
  • Limitations: Operator-dependent; misses retroperitoneal, bowel, contained organ injury.

⭐ > In unstable trauma patients, a positive FAST (free fluid) often indicates need for immediate surgical intervention (laparotomy).

FAST scan standard views and probe placement

Abdominal Trauma Imaging: CT Scanorama - Protocol Power

CT is key for stable abdominal trauma. Multiphase acquisition is standard.

  • CT Protocols:
    • Non-Contrast (NCCT): Baseline for hemorrhage, calcifications.
    • Arterial Phase (AP; 20-35s): Detects active bleeding, pseudoaneurysms, vascular injury.
    • Portal Venous Phase (PVP; 60-90s): Workhorse for solid organ (liver, spleen, kidney), bowel, mesenteric injury.
    • Delayed Phase (DP; 5-15 min): For urinary tract (collecting system, ureter, bladder) injury.

Multi-phase CT indications in abdominal trauma

  • Interpretation: Systematic approach. Identify lacerations, hematomas, active extravasation, free fluid/air.

⭐ The Portal Venous Phase is the most crucial single phase for evaluating solid organ and bowel injuries in trauma CT.

Abdominal Trauma Imaging: Solid Hits - Organ Grading Game

  • CECT Gold Standard: AAST organ injury scales (Grades I-V/VI) guide management.
  • Spleen (Most Common):
    • Grade I: Hematoma <10% surface area (SA) / Laceration (Lac) <1cm depth.
    • Grade II: Hematoma 10-50% SA / Intraparenchymal <5cm / Lac 1-3cm.
    • Grade III: Hematoma >50% SA / Ruptured or expanding / Intraparenchymal >5cm / Lac >3cm.
    • Grade IV: Laceration involving segmental/hilar vessels; Major devascularization (>25%).
    • Grade V: Shattered spleen; Hilar vascular injury (devascularized spleen). AAST Splenic Injury Grading
  • Liver:
    • Grade I: Hematoma <10% SA / Lac <1cm.
    • Grade II: Hematoma 10-50% SA / Intraparenchymal <10cm / Lac 1-3cm.
    • Grade III: Hematoma >50% SA / Ruptured or expanding / Intraparenchymal >10cm / Lac >3cm.
    • Grade IV: Parenchymal disruption 25-75% of a lobe or 1-3 Couinaud segments.
    • Grade V: Parenchymal disruption >75% of a lobe / Juxtahepatic venous injuries (retrohepatic IVC/major hepatic veins).
    • Grade VI: Hepatic avulsion.
  • Kidney:
    • Grade I: Contusion / Subcapsular hematoma, non-expanding.
    • Grade II: Laceration <1cm cortex; Non-expanding perirenal hematoma.
    • Grade III: Laceration >1cm cortex (no collecting system rupture).
    • Grade IV: Laceration into collecting system / Main renal artery/vein injury with contained hemorrhage.
    • Grade V: Shattered kidney; Renal pedicle avulsion / Devascularized kidney.

⭐ Active contrast extravasation ("blush") on CECT is a critical sign of ongoing hemorrhage, often warranting urgent intervention (embolization or surgery).

Abdominal Trauma Imaging: Guts & Gore - Viscus & Vascular Villains

  • Hollow Viscus Injury (HVI):
    • CT is primary imaging; oral contrast may aid.
    • Key signs:
      • Pneumoperitoneum (free air).
      • Bowel wall thickening (>3-4 mm), abnormal enhancement.
      • Mesenteric infiltration, hematoma, or interloop fluid.
      • Extraluminal oral contrast.
    • Delayed CT scans if initial findings equivocal but suspicion high.
    • Common sites: Jejunum, ileum (near points of fixation).
  • Vascular Injury:
    • MDCT Angiography (CTA) is gold standard.
    • Direct signs:
      • Active contrast extravasation ("arterial blush").
      • Pseudoaneurysm, intimal flap, dissection.
      • Vessel occlusion/transection.
    • Indirect signs: Hematoma (retroperitoneal, mesenteric), "sentinel clot" sign. Abdominal Trauma Findings Diagram

⭐ Isolated free fluid in blunt abdominal trauma, without solid organ injury, is highly suspicious for hollow viscus or mesenteric injury until proven otherwise.

High‑Yield Points - ⚡ Biggest Takeaways

  • FAST scan: Initial for unstable patients, detects free fluid.
  • CT with IV contrast: Gold standard for stable patients.
  • Solid organ injury grading (liver, spleen, kidney) guides management.
  • Active contrast extravasation on CT indicates ongoing bleeding, needs intervention.
  • Bowel/mesenteric injury: Look for free air, wall thickening, mesenteric stranding.
  • Diaphragmatic rupture: More common on left; "collar sign", organ herniation.
  • Retroperitoneal hematoma zones (I, II, III) direct surgical approach.

Practice Questions: Abdominal Trauma Imaging

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What is the investigation of choice for blunt abdominal trauma in an unstable patient?

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Flashcards: Abdominal Trauma Imaging

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What is the method of choice for staging a patient with hemodynamically stable renal trauma presenting at the emergency room?_____

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What is the method of choice for staging a patient with hemodynamically stable renal trauma presenting at the emergency room?_____

CECT

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