What does the ABCDE (Airway, Breach or Bones, Chest, Diaphragm, Everything else) approach in X-ray (radiographic imaging) evaluation entail?

ABCDE Approach to Chest X-Ray Interpretation

The ABCDE approach provides a systematic, priority-based framework for chest radiograph interpretation, ensuring no critical findings are missed by evaluating: Airway, Bones/Breach (chest wall), Cardiac silhouette/mediastinum (Chest), Diaphragm, and Everything else (soft tissues, tubes, lines). 1

Systematic Evaluation Framework

A - Airway

• Assess tracheal position and patency - deviation suggests tension pneumothorax, large pleural effusion, or mediastinal mass 1
• Evaluate for endotracheal tube placement if present - tip should be 3-5 cm above the carina 1
• Check for airway obstruction or foreign bodies 1

B - Bones and Breach (Chest Wall)

• Examine all ribs systematically for fractures, which may indicate underlying pulmonary contusion or pneumothorax 2, 1
• Assess clavicles and scapulae for fractures 1
• Evaluate for subcutaneous emphysema indicating air leak from pneumothorax or airway injury 1
• Check chest wall integrity for surgical emphysema or soft tissue abnormalities 1

C - Cardiac Silhouette and Mediastinum (Chest)

• Measure cardiac size - cardiothoracic ratio >0.5 on PA film suggests cardiomegaly 2, 1
• Assess mediastinal contours and width - widening may indicate aortic dissection, hemorrhage, or mass 3, 1
• Evaluate for pneumomediastinum 1
• Check hilar structures for lymphadenopathy or vascular abnormalities 1

D - Diaphragm

• Confirm normal diaphragmatic position and contour - right hemidiaphragm typically 1-2 cm higher than left 4, 1
• Look for free air under the diaphragm indicating bowel perforation requiring emergent surgical consultation 3, 4
• Assess for diaphragmatic hernia - stomach or bowel loops in chest cavity 4, 1
• Check costophrenic angles for blunting suggesting pleural effusion 1

E - Everything Else

• Examine lung parenchyma bilaterally for infiltrates, consolidation, masses, or nodules 2, 1
• Identify pneumothorax - look for visceral pleural line and absence of lung markings peripherally 2, 3, 1
• Assess for pleural effusions - meniscus sign, blunted costophrenic angles 1
• Verify placement of all lines and tubes - central lines, chest tubes, nasogastric tubes 1
• Check soft tissues including breast shadows and axillary regions 1

Critical Findings Requiring Immediate Action

Life-Threatening Conditions

• Tension pneumothorax - tracheal deviation, mediastinal shift, hemidiaphragm depression 2, 3
• Massive hemothorax - complete opacification of hemithorax 2
• Free air under diaphragm - bowel perforation requiring emergent surgery 3, 4
• Widened mediastinum - possible aortic dissection or rupture requiring emergent CTA 3

Important Clinical Caveats

Limitations of Chest Radiography

• Chest X-ray has poor sensitivity for pulmonary embolism - CT angiography is required when PE is suspected 2, 3
• Normal chest radiograph does not exclude pneumonia in early presentation or immunocompromised patients 2
• Radiographs miss up to 62% of diaphragmatic injuries - CT is superior for trauma evaluation 4
• Small pneumothoraces may be missed on supine films - upright or lateral decubitus views improve detection 1

When to Escalate to CT

• Penetrating thoracic trauma - CTA chest identifies vascular injuries, pseudoaneurysms, and active extravasation with 90-100% sensitivity 2, 3
• Suspected PE - CTPA is the primary imaging modality with superior sensitivity compared to chest X-ray 2, 3
• Acute respiratory illness with normal radiograph but high clinical suspicion - CT detects parenchymal abnormalities missed on plain films 2
• Mediastinal abnormalities requiring further characterization 3

Patient-Specific Considerations

• Elderly patients (>60 years) warrant lower threshold for imaging even with normal vital signs due to higher pneumonia risk and atypical presentations 2
• Immunocompromised patients may have normal chest radiographs despite significant pulmonary pathology 2
• Trauma patients require systematic evaluation for rib fractures, pneumothorax, hemothorax, and mediastinal injury 2