🩻 Chest X-ray Interpretation 🩻

Reading CXRs can feel overwhelming, but a structured approach saves lives (and embarrassment on ward rounds).

💡 How do X-rays work (quick refresher)?

X-rays are high-energy electromagnetic waves that pass through the body and are absorbed to varying degrees by different tissues.

Dense structures (like bone or metal) absorb more X-rays and appear white (radiopaque).

Air-filled structures (like lungs or bowel gas) absorb little, so they appear black (radiolucent).

Soft tissues and fluid (e.g. heart, liver, consolidation) absorb an intermediate amount and appear in shades of grey.

What you see on the film is essentially a 2D shadow of 3D anatomy — so always think in three dimensions, and beware of overlapping structures and projection artefacts.

Here’s the DRSABCDE framework — and yes, there’s an acronym inside the acronym.

A systematic approach to interpretation: 

🔎 D – Details

• 📋 Confirm patient name, date, and time. Always check you’re looking at the right X-ray — and the most recent one!

👀 R – RIPE

• Rotation – Medial clavicles should be equal distance from the spinous processes. Rotation can distort the appearance of the heart and mediastinum.
• Inspection – Any obvious pathology? Missing lung? Massive white-out?
• Projection – Is it PA or AP? (Hint: AP is common in ED/ICU — and the heart can look artificially enlarged).
• Exposure – Can you just see the vertebral bodies behind the heart? Overexposed = too black, underexposed = too white.

🫀 S – Soft tissues & bones

• Check for rib fractures, subcutaneous emphysema, clavicle or humeral fractures, or mastectomy changes.
• 💡 Example: Flail chest might show multiple adjacent rib fractures and soft tissue swelling.

🌬️ A – Airway

• Is the trachea midline? Look for deviation.
• 💡 Example: Tracheal shift away might suggest tension pneumothorax; towards could suggest collapse.

🫁 B – Breathing (lungs and pleura)

• Compare sides. Look for asymmetry, consolidation, pleural effusion, pneumothorax.
• 💡 Example: Blunting of costophrenic angle? Think pleural effusion.

❤️ C – Circulation (heart and mediastinum)

• Check heart size and mediastinum. Look for signs of cardiomegaly or widened mediastinum.
• 💡 Example: A boot-shaped heart? Consider tetralogy of Fallot in paeds. Widened mediastinum? Consider aortic dissection (especially with chest pain).

⬇️ D – Diaphragm

• Look at shape and contour. Right side usually slightly higher. Check for free gas.
• 💡 Example: Free air under diaphragm = perforated bowel (a surgical emergency).

🧰 E – Extras

• Look for lines, tubes, pacemakers, prostheses, surgical clips — and make sure they're correctly positioned!
• 💡 Example: NG tube coiled in the chest? It’s not in the stomach — don’t use it.

🩻 Quick quiz: Breathless and Hypoxic

Case:

A 72-year-old man presents with sudden-onset shortness of breath and pleuritic chest pain after a car accident. He is tachypnoeic and hypoxic on room air.

His chest X-ray shows a hyperlucent right hemithorax with no visible lung markings peripherally. The trachea is deviated to the left. (Xray below)

Question:

What is the most likely diagnosis?

• A. Right-sided pneumothorax
• B. Right lower lobe consolidation
• C. Right-sided pleural effusion
• D. Left main bronchus obstruction
• E. Left sided atelectasis

✅ Correct answer: A. Right-sided pneumothorax

💡 Rationale: The absence of lung markings and tracheal shift away from the affected side suggest a tension pneumothorax.

🧠 Final tip: Always interpret in the clinical context — and always compare to previous films if you can