Trauma imaging principles

Primary Survey Imaging - First Look, Fast!

• eFAST (Extended Focused Assessment with Sonography for Trauma): Rapid, portable, non-invasive ultrasound to detect life-threatening bleeding.
  • Goal: Identify free fluid (hemoperitoneum, pericardial effusion) or pneumothorax.
  • Views: Pericardial, Hepatorenal (Morrison's pouch), Splenorenal, Pelvic (suprapubic), bilateral anterior thoracic (for pneumothorax).

⭐ Exam Favourite: The eFAST exam is notoriously poor at detecting retroperitoneal hemorrhage, a critical limitation. It also cannot reliably quantify blood volume or identify the source of bleeding.

Secondary Survey Imaging - The Full Picture

• CT Scans: The cornerstone for stable patients after initial resuscitation.
  • Head & C-Spine: For suspected traumatic brain injury (TBI) or cervical spine fractures.
  • Chest, Abdomen, Pelvis (CAP): The "pan-scan" identifies organ injury, hemorrhage, and fractures. Typically performed with IV contrast.
• Plain Radiographs (X-rays):
  • Essential for suspected extremity fractures.
  • An AP pelvis film remains critical in blunt trauma, even if a CT is planned.
• Specialized Studies:
  • Angiography for suspected vascular injury.

⭐ The "trauma pan-scan" (CT of the head, neck, chest, abdomen, and pelvis) is the gold standard for hemodynamically stable major trauma patients, providing a rapid, comprehensive evaluation.

Imaging Modalities - Trauma Toolkit

• eFAST (Extended Focused Assessment with Sonography for Trauma):
  • Rapid bedside ultrasound to detect free fluid (hemoperitoneum, pericardial effusion) and pneumothorax.
  • The primary imaging for hemodynamically unstable torso trauma.
  • Limitations: Operator-dependent; poor for retroperitoneal injury.
• Portable Radiographs (X-ray):
  • AP Chest: Screens for pneumo/hemothorax, widened mediastinum, great vessel injury.
  • AP Pelvis: Essential for identifying pelvic fractures, a source of major hemorrhage.
• CT Scan (Computed Tomography):
  • Gold standard for hemodynamically stable patients.
  • "Pan-scan" (head, C-spine, chest, abdomen/pelvis with IV contrast) provides detailed anatomical assessment.

⭐ Transporting an unstable patient to the CT scanner is a high-risk decision; stabilize first.

Special Populations - Handle With Care

• Pregnant Patients

  • Prioritize maternal stabilization; a stable mother is the best fetal resuscitation.
  • Use lead shielding over the abdomen/pelvis for X-rays and CT scans.
  • MRI and Ultrasound are preferred modalities (no ionizing radiation).
  • Displace the uterus laterally after 20 weeks gestation to prevent aortocaval compression.

• Pediatric Patients

  • Children are more radiosensitive; strictly adhere to the ALARA (As Low As Reasonably Achievable) principle.
  • Utilize ultrasound (e.g., FAST) and MRI when possible.
  • Use weight-based radiation dose reduction protocols for CT scans.

⭐ In pregnant trauma, the risk of missing a life-threatening maternal injury almost always outweighs the potential fetal risk from diagnostic radiation.

High‑Yield Points - ⚡ Biggest Takeaways

• eFAST is the initial imaging for unstable patients, detecting hemoperitoneum and pericardial effusion.
• CT C-spine is mandatory to clear the neck in patients with altered mental status or distracting injuries.
• Chest X-ray in the primary survey rapidly identifies pneumothorax or hemothorax.
• IV contrast CT is the gold standard for stable abdominal trauma to assess organ injury.
• Non-contrast head CT is first-line for suspected TBI to find acute intracranial bleeds.