The ABCDE of Chest X-Rays

Systematic Interpretation for Finals

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Step 0: Check the Details

Before you start interpreting, ensure you have the correct patient. Check Name, DOB, and Date/Time of the image. Never comment on an X-Ray without verifying these first.

Step 1: Assessing Quality (RIPE)

If the image quality is poor, pathology can be mimicked or missed.

• R - Rotation: Look at the clavicle heads. They should be equidistant from the spinous processes. If rotated, the mediastinum may look artificially widened.
• I - Inspiration: You should see 5-6 anterior ribs or 8-10 posterior ribs above the diaphragm. Poor inspiration makes the heart look enlarged.
• P - Projection: AP (Anterior-Posterior) vs PA (Posterior-Anterior). Most portable films are AP, which magnifies the heart.
• E - Exposure: You should just barely be able to see the vertebral bodies behind the heart.

Step 2: The ABCDE Approach

A - Airway

Is the trachea central? If it is deviated, ask why.

• Pushed away: Tension pneumothorax or large pleural effusion.
• Pulled towards: Lobar collapse or pneumonectomy.

B - Breathing (Lungs & Pleura)

Divide the lungs into 3 zones (upper, middle, lower). Compare left vs right. Look for asymmetry. lung markings should reach the edge of the chest wall. If you see a sharp line with no markings beyond it, think Pneumothorax.

C - Cardiac

Heart Size: Cardio-thoracic ratio should be < 0.5 (only applies to PA films).
Heart Borders: Loss of a heart border implies consolidation in the adjacent lobe (Silhouette Sign).

D - Diaphragm

The Right hemidiaphragm is usually higher than the Left (due to the liver). Check the costophrenic angles. They should be sharp. If blunted, suspect Pleural Effusion.
Look for free air under the diaphragm (Pneumoperitoneum).

E - Everything Else

Do not forget the bones and soft tissues. Scan the ribs for fractures (trace each rib). Look for surgical emphysema (air in soft tissue). Check for lines, tubes, and pacemakers.

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