Start with the patient’s physiology and the clinical question. Check for an immediately actionable finding, then review the whole chest X-ray systematically. A reassuring film should not override persistent clinical concern.

1. Pre‑flight Check (RIPE)

• Rotation: spinous processes centered between clavicles
• Inspiration: assess lung volume; the 5th–7th anterior ribs usually intersect the diaphragm at the midclavicular line. Low volume can exaggerate heart size and basal opacity.
• Projection: PA or AP; erect or supine
• Exposure/penetration: faint spine visible behind the heart. Also verify the patient details and image date before interpretation.

2. ABCDE(F) System

Use the same sequence each time, and finish it even after finding an abnormality:

• A – Airways: Trachea midline? Deviations? Carina angle? Bronchial cutoff?
• B – Bones & Breathing: Ribs, clavicle, spine, look for fractures; lung fields—symmetry, markings, pleural lines.
• C – Cardiomediastinal: Assess heart borders, mediastinum and hila. In adults, a cardiothoracic ratio above 50% suggests enlargement on a well-inspired PA film; AP magnification limits this assessment.
• D – Diaphragm & Pleura: Trace both hemidiaphragms and costophrenic angles; look for pleural fluid and free subdiaphragmatic air.
• E – Extras: Trace each line and tube from entry to tip; check device position and soft tissues. Use device-specific placement criteria, including the NG-tube guidance below.
• (F) – Fields (Lung Parenchyma): Alveolar or interstitial patterns, zones, silhouette sign for subtle consolidations

3. High-Yield Acute Findings

Look for these findings on the first pass, then complete ABCDEF. A normal chest X-ray does not exclude important disease; escalate according to symptoms, physiology and pretest probability. See NICE trauma-imaging guidance.

• Pneumothorax: a visceral pleural line with no lung markings beyond it. On a supine film, look for an unusually deep, lucent costophrenic sulcus; the usual apical sign may be absent.
• Pleural fluid: costophrenic blunting or a meniscus when upright; posterior layering may be subtle when supine. In trauma, consider hemothorax in the clinical context.
• Pulmonary edema: septal (Kerley B) lines or perihilar airspace opacity. Heart enlargement and effusions support a cardiogenic cause, interpreted with the clinical findings.
• Pneumomediastinum – lucent streaks along mediastinal borders, continuous diaphragm sign
• Airspace opacity: look for consolidation, air bronchograms and loss of an adjacent heart or diaphragm border. Pneumonia is one cause; correlate with symptoms and examination.

4. Pitfall Zones

Hidden areas merit extra attention:

• Lung apices
• Retro‑cardiac zones (e.g., left lower lobe)
• Sub‑diaphragmatic lung bases
• Hilar region for lymphadenopathy or masses

5. Compare & Correlate

• Always correlate with clinical context and your physical exam—history guides focus
• Compare with prior films, accounting for projection and inspiration. Assess both new changes and persistent abnormalities.

6. Next Steps

• If tension pneumothorax is suspected with haemodynamic instability or severe respiratory compromise, treat immediately rather than wait for imaging. Use further CT/ultrasound when clinically safe. See NICE chest-trauma recommendations.
• Review the radiology report, resolve important discrepancies and arrange follow-up for unresolved findings.

 TL;DR – Your ED CXR Workflow

1. Check physiology, patient details and RIPE; scan for an urgent finding
2. ABCDE(F) fields systematically
3. Look for critical pathology; escalate if clinical concern persists despite a normal CXR
4. Inspect subtle zones
5. Clinical correlation and prior film comparison
6. Escalate imaging when needed

Further reading: Radiology Assistant: systematic interpretation and acute findings; Radiology Masterclass: projection; pleural disease; pulmonary edema.

Chest X-ray teaching guide: Read the annotations alongside the radiographs, especially the guidance accompanying the superseded labels on page 16. Key interpretation points: page 3’s 5–7-rib inspiration criterion refers to anterior ribs; a normal CXR does not exclude an inhaled foreign body (page 5); the thymus is in the anterior mediastinum, not the hilum (page 15). On page 16, standard upper-body central-line tip guidance should refer to the lower SVC/cavoatrial region, with device-specific requirements. An NG-tube tip overlying the gastric bubble alone does not confirm safe placement: check the entire tube course and intragastric tip position according to the local placement-verification protocol before use. Sources: inspiration assessment; RCH inhaled foreign bodies; NCI thymus anatomy; eviQ central-line guidance; HSSIB NG-tube safety.

CXR annotated corrected edition — 9 October 2026Download