Chest Trauma Imaging

Initial Scan & Scope - Trauma Triage Tools

• Primary Survey (ABCDE): Crucial first step. Imaging aids 'B' (Breathing - pneumothorax) & 'C' (Circulation - hemothorax, tamponade).
• eFAST (Extended FAST): Bedside ultrasound for immediate life-threats: pneumothorax, hemothorax, pericardial effusion.
  • 📌 Key Chest Views: Bilateral anterior & lateral thoracic scans (parasternal, midclavicular, axillary lines).
  • Findings:
    • Pneumothorax: Absent lung sliding ("barcode sign" on M-mode); lung point (pathognomonic, confirms PTX).
    • Hemothorax: Anechoic/hypoechoic fluid in pleural space.

  ⭐ eFAST has a high specificity but moderate sensitivity for detecting pneumothorax and hemothorax in trauma patients.

• Chest X-Ray (CXR - AP Supine): Initial, widely available.
  • Limitations: Supine position hinders detection (small pneumothorax, layering effusions), magnification.
  • Key Findings: Pneumothorax, hemothorax, widened mediastinum (aortic injury soft sign: >8cm), fractures, contusions.
• MDCT Chest: Gold standard for definitive diagnosis of complex injuries.
  • Indications: High-energy trauma, abnormal/equivocal CXR/eFAST, suspected vascular (CTA), tracheobronchial, diaphragmatic injury.
  • Protocols: Whole-body CT (WBCT) for polytrauma; CTA for arterial injury.

Ribs, Air & Blood - Walls & Linings

• Rib Fractures: Most common chest trauma.

  • Complications: Pulmonary contusion, neurovascular/visceral injury.
  • Associated injuries by location:

    Ribs	Associated Injury Potential
    1-3	Major vascular (subclavian), brachial plexus, lung
    4-8	Lung (pneumothorax, contusion)
    9-12	Liver, spleen, kidneys (solid abdominal organs)

  ⭐ First and second rib fractures are markers of severe trauma and have a high association with vascular and brachial plexus injuries.

• Flail Chest:

  • Definition: ≥3 consecutive ribs fractured in ≥2 places.
  • Key sign: Paradoxical chest wall movement.
  • Often requires mechanical ventilation.

• Sternal Fractures:

  • High-energy trauma; suspect cardiac/aortic injury (ECG, enzymes, CT aortogram).

• Scapular Fractures:

  • Marker of significant trauma force; associated injuries common.

• Pneumothorax (Air in Pleural Space):

  • Simple: Air, no mediastinal shift.
  • Tension: Medical emergency!
    • Signs: Hypotension, JVD, tracheal deviation (away), ↓air entry.
    • Imaging: CXR (visceral line, deep sulcus), CT (most sensitive).
    • Needle Decompression: 2nd ICS MCL or 5th ICS AAL/MAL.
  • Occult: Seen on CT, not CXR.

• Hemothorax (Blood in Pleural Space):

  • Imaging: CXR (meniscus, opacification), CT.
  • Massive Hemothorax:

    • 1500ml initial drainage.

    • OR >200ml/hr for 2-4 hours.
    • Requires urgent thoracotomy.

Lungs, Airways & Great Vessels - Deep Impact Damage

• Pulmonary Contusion: Most common. Lung "bruising"; opacities on CXR/CT (ground-glass, consolidation). Appears <6 hrs, resolves 3-7 days.
• Pulmonary Laceration/Hematoma: Parenchymal tear. CT: air/fluid-filled cavities, hematoma.
• Tracheobronchial Injury (TBI): Rare, high mortality. Persistent pneumothorax despite chest tube.

  ⭐ The 'fallen lung' sign on CXR is highly suggestive of a major tracheobronchial injury.

• Aortic & Great Vessel Injury:
  • Mechanisms: Deceleration, penetrating.
  • 📌 CT Signs: Direct (Intimal flap, Pseudoaneurysm, Active extravasation, Irregular contour); Indirect (Mediastinal hematoma >1cm, periaortic hematoma).

• Diaphragmatic Rupture: More common on left (~90%). "Collar sign" (constriction of herniated organ). Herniation of abdominal contents.
• Esophageal Injury: Rare. Odynophagia, hematemesis, mediastinal air. Gastrografin swallow or CT with oral contrast.
• Cardiac Injury: Blunt Cardiac Injury (BCI) spectrum. Tamponade risk. CT: pericardial effusion, myocardial hematoma.

High‑Yield Points - ⚡ Biggest Takeaways

• CXR is first-line for detecting pneumothorax, hemothorax, and rib fractures.
• CT Chest is the gold standard for detailed evaluation, especially in polytrauma or equivocal CXR.
• Tension pneumothorax: Look for mediastinal shift away from the affected side.
• Aortic injury: Widened mediastinum on CXR is a critical sign; CTA confirms.
• Pulmonary contusion: Patchy opacities appearing ~6 hours post-trauma, typically resolving in 3-7 days.
• Diaphragmatic rupture: More common on the left; suspect with bowel sounds in chest or NG tube coiled in thorax.
• Flail chest: ≥3 consecutive ribs fractured in ≥2 places leading to paradoxical chest wall movement.