Clinical imaging: Chest X-ray and cardiothoracic imaging

🩻 Chest X-ray and cardiothoracic imaging - page 2 of the Clinical Imaging chapter. The chest X-ray is the commonest imaging test in medicine, and junior doctors often act on it before a radiologist's report is available - confirming pneumonia, spotting a pneumothorax, checking an NG tube, or finding an unexpected cancer. A consistent system prevents missed findings. CT, echocardiography and cardiac imaging extend what the X-ray can show.
Your four questions for every chest X-ray: Who is the patient, and is the film adequate? What does a systematic review show - including the review areas? How does this compare with previous films? What needs doing now - and who needs to know?

---

Is the Film Adequate?

• Check the details first - correct patient (name, date of birth), date and time, projection (PA, AP, supine, erect), side markers.
• RIPE:
  • Rotation - the medial ends of the clavicles should be equidistant from the spinous processes; rotation alters heart and mediastinal appearance.
  • Inspiration - about 6 anterior ribs or 10 posterior ribs above the diaphragm at the mid-clavicular line; poor inspiration crowds lung markings and enlarges the heart; hyperinflation (over 7 anterior ribs, flat diaphragms) suggests COPD or asthma.
  • Projection - PA (standard; scapulae clear of lungs) vs AP (portable - heart magnified, so the cardiothoracic ratio can't be judged reliably); supine films redistribute fluid and air (effusions look like haziness; pneumothorax collects anteriorly).
  • Exposure - the vertebral bodies should be just visible through the heart; overexposed films look dark (missed nodules), underexposed look white.
• Coverage - both apices, both costophrenic angles and lateral chest walls.
• Compare with previous films - the single most useful step; a stable nodule over 2 years is likely benign.

A Systematic Approach

• ABCDE (one common system):
  • A - Airway - trachea central (deviated away from tension pneumothorax and large effusion; towards collapse and pneumonectomy), carina, main bronchi.
  • B - Breathing (lungs and pleura) - compare zones side by side (upper, middle, lower); look for consolidation, nodules, masses, collapse, interstitial change, pneumothorax, effusion; check the lung edges.
  • C - Circulation (heart and mediastinum) - heart size (cardiothoracic ratio under 0.5 on a PA film), heart borders, mediastinal width and contour, aortic knuckle, hila (left normally higher than right).
  • D - Diaphragm - the right hemidiaphragm is usually higher; sharp costophrenic angles; free air under the diaphragm; gastric bubble position.
  • E - Everything else - bones (ribs, clavicles, spine, shoulders), soft tissues (breast shadows, surgical emphysema), lines, tubes and devices.
• Review areas (where findings are commonly missed) - apices, behind the heart, hila, below the diaphragm (and behind it), the bones, and the edges of the film.
• Describe abnormalities - location (zone, lobe), size, shape, density, margins, effect on surrounding structures, comparison with previous; then a differential and a plan.
• Satisfaction of search - after finding one abnormality, keep looking (e.g. a rib fracture plus a pneumothorax; a pneumonia plus a hidden lung cancer).

Normal Anatomy and Review Areas

• Lobes - right - upper, middle and lower (horizontal and oblique fissures); left - upper (including the lingula) and lower (oblique fissure). The horizontal fissure may be visible at the right 4th anterior rib.
• Zones on the PA film don't equal lobes - the lower lobes extend high posteriorly; the lateral film helps localise.
• Heart borders:
  • Right heart border - right atrium - next to the right middle lobe.
  • Left heart border - left ventricle - next to the lingula.
  • Hemidiaphragms - next to the lower lobes.
• Mediastinal contours - right: SVC, right atrium; left: aortic knuckle, pulmonary trunk, left atrial appendage, left ventricle.
• Hila - mainly pulmonary arteries and veins; the left hilum is usually higher than or level with the right; should be similar in size and density.
• Review areas:
  • Apices - Pancoast tumour, TB, small pneumothorax, rib lesions.
  • Behind the heart - left lower lobe collapse or consolidation, hiatus hernia (air–fluid level), masses.
  • Hila - masses, lymph nodes, density.
  • Below the diaphragm - free gas, dilated bowel, calcified gallstones, subphrenic abscess, splenomegaly.
  • Bones - fractures, lytic or sclerotic metastases, cervical rib, missing ribs (surgery).
  • Soft tissues - mastectomy (one side more lucent), surgical emphysema.

Consolidation and the Silhouette Sign

• Consolidation - airspaces filled with fluid, pus, blood, cells or protein - pneumonia (commonest), pulmonary oedema, haemorrhage, aspiration, organising pneumonia, adenocarcinoma (lepidic), eosinophilic pneumonia.
• Signs:
  • Ill-defined opacification, often lobar or segmental.
  • Air bronchograms - black branching airways visible within white lung.
  • No volume loss (unlike collapse).
• Silhouette sign - localising consolidation:

  Border lost	Lobe involved
  Right heart border	Right middle lobe
  Left heart border	Lingula (left upper lobe)
  Right hemidiaphragm	Right lower lobe
  Left hemidiaphragm (behind the heart)	Left lower lobe
  Aortic knuckle / upper mediastinum	Left upper lobe (apicoposterior) / right upper lobe

• Lower lobe consolidation with a preserved heart border but lost diaphragm outline.
• Pattern clues:
  • Lobar - pneumococcal pneumonia.
  • Upper lobe with cavitation - TB, Klebsiella.
  • Multifocal or bilateral - atypical pneumonia, COVID-19, Staph aureus (with cavities and pneumatoceles), PCP (perihilar ground glass), aspiration (dependent - right lower lobe, posterior segments).
  • Perihilar "bat's wing" - pulmonary oedema.
• Follow-up - chest X-ray changes lag behind clinical improvement (up to 6 weeks); BTS - repeat chest X-ray at about 6 weeks for persisting symptoms or high cancer risk (smokers, over 50) to ensure resolution.

Lobar Collapse

• Collapse (atelectasis) - loss of lung volume; causes - endobronchial obstruction (tumour - always exclude in adults, mucus plug, foreign body - right main bronchus in children and adults), extrinsic compression (nodes), post-operative.
• Signs of volume loss - displaced fissures, tracheal and mediastinal shift towards the collapse, raised hemidiaphragm, crowded ribs, hilar displacement, compensatory hyperinflation of other lobes.
• Patterns:
  • Right upper lobe - dense triangle at the right apex with elevated horizontal fissure; a central mass gives the Golden S sign (reverse S of the fissure - suspect tumour).
  • Right middle lobe - loss of the right heart border; subtle on PA (clearer on lateral).
  • Right lower lobe - triangular density at the right base; loss of the right hemidiaphragm, right heart border preserved.
  • Left upper lobe - collapses forwards - hazy "veil-like" opacity over the left hemithorax, loss of left heart border; Luftsichel sign (crescent of air next to the aortic knuckle).
  • Left lower lobe - triangular opacity behind the heart - the "sail sign" - with loss of the medial left hemidiaphragm; a double left heart border.
  • Whole lung - "white-out" with mediastinal shift towards the white side.
• White-out - which way does the trachea go? - towards - collapse or pneumonectomy; away - large effusion or mass; central - consolidation or mesothelioma (encasement).
• Lobar collapse in an adult - bronchoscopy or CT to exclude an obstructing tumour.

Nodules, Masses and Cavities

• Nodule - under 3 cm; mass - 3 cm or more (more likely malignant).
• Suspicious features - larger size, spiculated or irregular margins, growth over time, upper lobe, associated hilar or mediastinal nodes, rib destruction, smoker or older age.
• Benign features - calcification (central, laminated, diffuse, "popcorn" in hamartoma), stability over 2 years, small size, smooth margins.
• Single nodule causes - lung cancer, metastasis, granuloma (TB, histoplasmosis), hamartoma, carcinoid, rounded pneumonia, abscess, rheumatoid nodule, GPA, AVM, nipple shadow (bilateral, symmetrical - repeat with markers).
• Multiple nodules - metastases ("cannonballs" - kidney, colon, sarcoma, melanoma, testis, thyroid), septic emboli, GPA, rheumatoid nodules, sarcoidosis, TB, silicosis.
• Cavities - TB (upper lobe), lung abscess (air–fluid level; aspiration - alcohol, poor dentition), squamous cell carcinoma (thick irregular wall), Staph aureus and Klebsiella, GPA, septic emboli (IV drug use - tricuspid endocarditis), aspergilloma ("fungal ball" in an old cavity - air crescent sign), rheumatoid nodules, PE infarction.
• Pancoast tumour - apical mass with rib destruction - Horner's syndrome, C8–T1 pain and wasting (hand), brachial plexopathy.
• NICE NG12 - offer an urgent chest X-ray (within 2 weeks) for people over 40 with unexplained cough, fatigue, breathlessness, chest pain, weight loss or appetite loss (2 or more, or 1 if they have ever smoked); refer suspected lung cancer on the chest X-ray via a suspected cancer pathway; a normal chest X-ray doesn't exclude lung cancer (about 1 in 5 missed) - CT if symptoms persist.

Interstitial and Diffuse Patterns

• Reticular (lines) and reticulonodular patterns - interstitial lung disease, lymphangitis, oedema.
• Distribution helps:
  • Upper zone fibrosis - "CHARTS" - Coal workers' pneumoconiosis, Hypersensitivity pneumonitis (chronic), Ankylosing spondylitis, Radiation, TB, Sarcoidosis and silicosis; also ABPA, Langerhans cell histiocytosis.
  • Lower zone fibrosis - idiopathic pulmonary fibrosis (UIP pattern), connective tissue disease (RA, systemic sclerosis), asbestosis, drugs (amiodarone, methotrexate, nitrofurantoin, bleomycin).
• Honeycombing - clustered cystic airspaces at the bases - end-stage fibrosis (UIP).
• Bilateral hilar lymphadenopathy - sarcoidosis (with or without lung changes - Scadding stages), lymphoma, TB, metastases.
• Miliary pattern - innumerable tiny (1–3 mm) nodules - miliary TB (immunosuppressed), metastases (thyroid, melanoma), sarcoidosis, varicella pneumonia (healed - calcified), silicosis.
• Lymphangitis carcinomatosa - septal lines and nodularity with hilar nodes - breast, lung, stomach, pancreas cancers.
• Bilateral diffuse airspace shadowing - pulmonary oedema (cardiogenic), ARDS (non-cardiogenic - normal heart size, no effusions often), diffuse alveolar haemorrhage (vasculitis, anti-GBM), PCP, widespread pneumonia (COVID-19).
• Further imaging - HRCT for suspected ILD (see below).

COPD, Bronchiectasis and Asbestos

• COPD and emphysema - hyperinflation (over 6–7 anterior ribs), flattened hemidiaphragms, increased retrosternal airspace (lateral), narrow "tubular" heart, bullae (don't mistake a large bulla for a pneumothorax - CT if unsure); prominent pulmonary arteries in pulmonary hypertension.
• Asthma - usually normal; hyperinflation in acute attacks; chest X-ray for suspected pneumothorax, pneumonia or life-threatening attacks.
• Bronchiectasis - thickened bronchial walls ("tramlines" and "ring shadows"), sometimes with fluid levels; CT is the diagnostic test (bronchus wider than the accompanying artery - "signet ring" sign).
• Cystic fibrosis - upper lobe bronchiectasis, hyperinflation, mucus plugging.
• Asbestos-related disease:
  • Pleural plaques - calcified, "holly-leaf" or linear plaques on the diaphragm and lateral chest wall - markers of exposure, benign, not premalignant.
  • Diffuse pleural thickening - restrictive symptoms.
  • Asbestosis - lower zone fibrosis.
  • Mesothelioma - unilateral pleural thickening or effusion, nodular, encasing the lung (no mediastinal shift); compensation (industrial injuries disablement benefit).
  • Lung cancer - risk multiplied by smoking.
• Old TB - upper lobe fibrosis, volume loss, calcified granulomas and nodes, thoracoplasty (old surgical treatment).

Pleural Effusion

• Signs:
  • Blunting of the costophrenic angle (needs about 200 mL on an erect PA film; about 50 mL on a lateral).
  • Meniscus - concave upper edge rising laterally.
  • Large effusions - homogeneous opacity with mediastinal shift away.
  • Supine film - diffuse haziness of the hemithorax with visible vessels (fluid layers posteriorly) - easily missed.
  • Subpulmonic effusion - apparent raised hemidiaphragm with a lateral peak; increased distance between the stomach bubble and lung on the left.
  • Fluid in the fissures - "pseudotumour" (disappears with treatment of heart failure).
• Bilateral effusions - usually transudates (heart failure, hypoalbuminaemia, renal failure); unilateral - think infection, cancer, PE, TB (but heart failure can be unilateral - usually right-sided).
• Ultrasound - more sensitive than X-ray; shows septations (empyema), guides aspiration and drains (BTS - use ultrasound guidance for all pleural procedures for fluid).
• CT with contrast - pleural thickening and nodularity (malignancy, mesothelioma), empyema ("split pleura" sign), underlying mass; ideally before draining all the fluid when malignancy is suspected.
• Haemothorax (trauma) - effusion on erect film; CT.

Pneumothorax

• Signs - a thin visceral pleural line with no lung markings beyond it; best seen at the apex; look carefully at the lateral edges.
• Pitfalls:
  • Skin folds (extend beyond the chest wall, lung markings visible beyond), bullae (concave inner margin; CT if uncertain), the edge of the scapula, clothing and lines.
  • Supine film - air collects anteriorly - deep sulcus sign (deep, lucent costophrenic angle), unusually sharp heart border or diaphragm - CT in trauma.
  • An expiratory film is not routinely needed.
• Size - measured at the hilum level (inter-pleural distance - 2 cm or more is "large" per BTS 2010) - but BTS 2023 emphasises symptoms and physiology rather than size alone in deciding on intervention.
• Tension pneumothorax - a clinical diagnosis (respiratory distress, hypotension, tracheal deviation away, absent breath sounds) - decompress before imaging (needle or finger thoracostomy, then chest drain). Imaging shows a large pneumothorax, mediastinal shift away and a flattened or inverted hemidiaphragm.
• CT - small or occult pneumothoraces (trauma), assessment of underlying lung disease (secondary pneumothorax, recurrent), bullae vs pneumothorax.
• Ultrasound - absent lung sliding, absent B-lines, "lung point" (diagnostic) - sensitive in trauma (eFAST).
• Surgical emphysema - streaky lucency in the soft tissues; pneumomediastinum - air outlining mediastinal structures (asthma, vomiting - Boerhaave's, trauma, cocaine).

Pulmonary Oedema and the Heart

• Signs of heart failure - "ABCDE":
  • A - Alveolar oedema - perihilar "bat's wing" shadowing.
  • B - Kerley B lines (short horizontal lines at the lung periphery - interstitial oedema).
  • C - Cardiomegaly (CTR over 0.5 on a PA film).
  • D - Dilated upper lobe vessels (upper lobe diversion).
  • E - Effusions (bilateral, often right larger) and fluid in the fissures.
• Cardiogenic vs non-cardiogenic - ARDS and other non-cardiogenic oedema usually have a normal heart size, no upper lobe diversion, fewer effusions, more peripheral distribution.
• Heart size and shape:
  • Cardiomegaly - heart failure, cardiomyopathy, valve disease, pericardial effusion (large, globular "water-bottle" heart with clear lungs - echo urgently).
  • Left atrial enlargement (mitral stenosis) - straightened left heart border, double right heart border, splayed carina.
  • Pericardial calcification - constrictive pericarditis (TB).
  • Valve and annular calcification, prosthetic valves, sternotomy wires, pacemaker leads.
• Lung ultrasound - multiple B-lines (bilateral) support pulmonary oedema; useful at the bedside.
• A normal chest X-ray doesn't exclude heart failure - NT-proBNP and echocardiography (NICE NG106).

Hila and Mediastinum

• Hilar enlargement:
  • Unilateral - lung cancer (central tumour or nodes), TB, lymphoma, metastases.
  • Bilateral - sarcoidosis (bilateral hilar lymphadenopathy), lymphoma, TB, pulmonary arterial hypertension (enlarged pulmonary arteries - "pruning" peripherally), silicosis ("eggshell" calcification).
• Widened mediastinum - aortic dissection or traumatic aortic injury (chest pain, unequal pulses - CT aortogram urgently; a normal chest X-ray doesn't exclude dissection), lymphadenopathy, lymphoma, retrosternal thyroid, haematoma, AP projection and rotation (false widening).
• Mediastinal masses by compartment:
  • Anterior - the "4 Ts" - Thymoma (myasthenia), Teratoma and germ cell tumours, Thyroid (retrosternal goitre), "Terrible" lymphoma.
  • Middle - lymph nodes (lymphoma, sarcoid, cancer), bronchogenic and pericardial cysts, aortic aneurysm, hiatus hernia (retrocardiac air–fluid level).
  • Posterior - neurogenic tumours (schwannoma, neurofibroma, neuroblastoma in children), paravertebral abscess, descending aortic aneurysm, oesophageal tumours, extramedullary haematopoiesis.
• Hilum overlay sign - hilar vessels visible through a mass mean the mass isn't hilar (anterior or posterior).
• CT with contrast characterises mediastinal and hilar abnormalities.

Below the Diaphragm and the Bones

• Free intraperitoneal gas (pneumoperitoneum) - crescent of air under the hemidiaphragm on an erect chest X-ray (sit the patient up for 10 minutes first) - perforated viscus (peptic ulcer, diverticulum) - or normal after recent surgery or laparoscopy (up to about a week). CT is more sensitive.
  • Chilaiditi's sign - bowel interposed between liver and diaphragm (haustra visible) - mimics free gas.
  • The gastric bubble under the left hemidiaphragm is normal.
• Other abdominal findings - dilated bowel, calcified gallstones, hepatosplenomegaly, subphrenic abscess (raised hemidiaphragm, effusion), hiatus hernia.
• Raised hemidiaphragm - phrenic nerve palsy (lung cancer, surgery), lobar collapse, subphrenic abscess, hepatomegaly, eventration, subpulmonic effusion.
• Bones:
  • Rib fractures (often missed - multiple fractures in older people after falls; flail segment; consecutive posterior rib fractures in infants - non-accidental injury).
  • Lytic lesions - myeloma, metastases (lung, kidney, thyroid, breast); sclerotic - prostate, breast.
  • Clavicle and shoulder fractures and dislocations; vertebral collapse; cervical ribs; rib notching (coarctation of the aorta).
• Soft tissues - mastectomy, breast implants, surgical emphysema, calcified nodes.

Lines, Tubes and Devices

Device	Correct position	Watch for
Nasogastric tube	Stays in the midline down the oesophagus, bisects the carina, crosses the diaphragm in the midline, tip clearly below the left hemidiaphragm (at least 10 cm into the stomach)	Placement in a bronchus or lung - never feed - a Never Event
Endotracheal tube	Tip about 5–7 cm above the carina (mid-trachea) with the neck neutral	Right main bronchus intubation (left lung collapse), too high (extubation risk)
Central venous catheter (internal jugular, subclavian)	Tip in the lower SVC or cavoatrial junction (about at the level of the carina or just below)	Pneumothorax, misplacement (into the opposite subclavian or neck veins), arterial placement, tip in the right atrium (arrhythmias)
PICC line	As for CVC	Coiling, misplacement
Chest drain	Within the pleural space; side holes inside the chest; apical for air, basal for fluid	Subcutaneous placement, kinking, intrapulmonary or fissural placement, surgical emphysema
Pacemaker / ICD	Generator in the chest wall; leads in the right atrium and/or right ventricle (± coronary sinus for CRT)	Lead displacement or fracture, pneumothorax after insertion
Tracheostomy	Tip about a third of the way between the stoma and the carina	Displacement, surgical emphysema

• NG tube confirmation (NHS Patient Safety) - first-line test is aspirate pH 1–5.5; if no aspirate or pH over 5.5, a chest X-ray must be reviewed by a competent person using the four criteria above; document the decision - feeding through a misplaced tube is a Never Event.
• Always check new line and tube positions before use; report and remove misplaced devices.

⚠️ Safety Pearl: Never confirm an NG tube on a chest X-ray just because the tip is "somewhere below the diaphragm" on a quick look. Follow it all the way: midline, bisecting the carina, crossing the diaphragm in the midline, tip clearly below the left hemidiaphragm. If in doubt, don't feed - get a senior or radiology opinion.

Chest CT - CTPA, HRCT and Staging

• CT pulmonary angiography (CTPA) - first-line imaging for suspected PE (filling defects in pulmonary arteries); also shows RV strain (RV:LV ratio over 1), infarcts, alternative diagnoses (pneumonia, dissection, cancer); V/Q if contrast contraindicated or in pregnancy (with normal chest X-ray).
• High-resolution CT (HRCT) - thin sections, no contrast - interstitial lung disease, bronchiectasis, emphysema:
  • UIP pattern (IPF) - basal, subpleural honeycombing with traction bronchiectasis - can allow diagnosis of IPF without biopsy in the right clinical context (ILD MDT).
  • NSIP - ground glass with subpleural sparing (connective tissue disease).
  • Hypersensitivity pneumonitis - centrilobular nodules, mosaic attenuation, air trapping on expiratory images.
  • Sarcoidosis - perilymphatic nodules, hilar nodes.
  • Ground-glass opacity - infection (PCP, COVID-19), oedema, haemorrhage, early fibrosis, adenocarcinoma.
• Staging CT (chest, abdomen and pelvis with contrast) - lung cancer, other cancers; PET-CT before radical treatment for lung cancer; EBUS for mediastinal node sampling.
• Lung cancer screening - the NHS Lung Cancer Screening Programme (from the Targeted Lung Health Check) offers low-dose CT to people aged 55–74 with a history of smoking, after risk assessment - finds cancers at an earlier, treatable stage; nodules managed by protocol.
• CT thorax in trauma - rib fractures, haemopneumothorax, aortic injury, pulmonary contusion.
• CT for pleural disease - pleural thickening, mesothelioma, empyema.

Cardiac and Aortic Imaging

• Transthoracic echocardiography (TTE) - the workhorse - LV size and ejection fraction (heart failure classification - HFrEF under 40%, HFmrEF 41–49%, HFpEF 50% or more), wall motion, valves (stenosis, regurgitation), pericardial effusion and tamponade, RV size and pressures (PE, pulmonary hypertension), congenital defects.
• Transoesophageal echo (TOE) - endocarditis (vegetations, abscess - especially prosthetic valves), left atrial appendage thrombus before cardioversion, aortic dissection, valve surgery planning.
• Stress imaging - stress echo, myocardial perfusion scintigraphy (SPECT), stress cardiac MRI - inducible ischaemia.
• CT coronary angiography (CTCA) - first-line test for stable chest pain of suspected coronary origin (NICE CG95, updated 2016) - excludes coronary disease with high negative predictive value; calcium score; FFR-CT for functional significance.
• Invasive coronary angiography - acute coronary syndromes, before revascularisation (PCI or CABG).
• Cardiac MRI - myocarditis, cardiomyopathies (HCM, ARVC, amyloid, sarcoid - late gadolinium enhancement patterns), viability, iron overload (T2*), congenital disease, masses.
• Aortic imaging:
  • CT aortogram - suspected aortic dissection (intimal flap - Stanford A involves the ascending aorta - surgery; B - medical or endovascular), aneurysm, traumatic aortic injury.
  • Ultrasound - abdominal aortic aneurysm screening and surveillance (see page 3).
• Peripheral vascular imaging - arterial duplex, CT or MR angiography (peripheral arterial disease, acute limb ischaemia); carotid duplex (TIA and stroke - see page 6).

Chest X-ray Signs at a Glance

Sign	Meaning
Air bronchogram	Consolidation (airspace disease)
Loss of right heart border	Right middle lobe disease
Loss of left heart border	Lingula disease
Sail sign (behind heart)	Left lower lobe collapse
Veil-like left opacity	Left upper lobe collapse
Golden S sign	Right upper lobe collapse with a central mass
Meniscus, blunted angle	Pleural effusion
Visceral pleural line, no markings beyond	Pneumothorax
Deep sulcus sign	Pneumothorax on a supine film
Bat's wing, Kerley B lines, upper lobe diversion	Pulmonary oedema
Globular heart, clear lungs	Pericardial effusion
Bilateral hilar lymphadenopathy	Sarcoidosis (or lymphoma, TB)
Cannonball nodules	Metastases
Miliary nodules	Miliary TB
Cavity with air–fluid level	Lung abscess (also TB, SCC, staph)
Calcified holly-leaf plaques	Asbestos pleural plaques
Tramlines and ring shadows	Bronchiectasis
Free gas under diaphragm	Perforated viscus (or recent surgery)
Rib notching	Coarctation of the aorta
Widened mediastinum	Aortic dissection or injury, nodes, thyroid

Spot the Diagnosis

Clue	Diagnosis
Fever, cough, and opacity with air bronchograms that obscures the right heart border	Right middle lobe pneumonia
Triangular density behind the heart with loss of the medial left hemidiaphragm	Left lower lobe collapse
Hazy left hemithorax with a lost left heart border; trachea pulled left	Left upper lobe collapse - exclude tumour
White hemithorax with trachea pushed away	Large pleural effusion
White hemithorax with trachea pulled towards it	Whole lung collapse or pneumonectomy
Tall thin young man, sudden pleuritic pain, apical pleural line	Primary spontaneous pneumothorax
Hypotension, tracheal deviation and absent breath sounds after a central line	Tension pneumothorax - decompress before X-ray
Bilateral perihilar shadowing, cardiomegaly and small effusions	Cardiogenic pulmonary oedema
Bilateral airspace shadowing with a normal heart size after sepsis	ARDS
Large globular heart with clear lungs and low-voltage ECG	Pericardial effusion
Bilateral hilar nodes with erythema nodosum in a young woman	Sarcoidosis (Löfgren's)
Upper lobe cavitation, weight loss and night sweats	Pulmonary TB
Thick-walled cavity in a smoker with hypercalcaemia	Squamous cell lung cancer
Apical mass with rib destruction and Horner's syndrome	Pancoast tumour
Anterior mediastinal mass with fatigable ptosis	Thymoma
Basal reticular change on amiodarone	Amiodarone pulmonary toxicity
Calcified diaphragmatic plaques in a retired shipbuilder	Asbestos pleural plaques (benign)
Air under the right hemidiaphragm with sudden epigastric pain	Perforated peptic ulcer
NG tube following the right main bronchus	Misplaced NG tube - don't feed
ET tube tip in the right main bronchus; left lung white	Endobronchial intubation - pull back
Basal subpleural honeycombing on HRCT in a 72-year-old with crackles	UIP - idiopathic pulmonary fibrosis
Rib notching and hypertension in a young adult	Coarctation of the aorta

Exam-style Scenarios

1. A 67-year-old smoker has had a cough for 6 weeks. Chest X-ray shows a right upper lobe opacity with an elevated horizontal fissure that curves downwards laterally and bulges centrally.
Answer: Right upper lobe collapse with a central mass - Golden S sign - suspected lung cancer.

• Urgent suspected cancer referral; contrast CT chest and upper abdomen (staging).
• Bronchoscopy or EBUS for tissue; PET-CT if radical treatment is considered.
• Lung cancer MDT; smoking cessation; performance status assessment.

2. An 80-year-old woman with dementia has an NG tube inserted for feeding. No aspirate can be obtained. Chest X-ray shows the tube passing down the midline but the tip is not clearly seen below the diaphragm.
Answer: NG tube position not confirmed - do not use.

• Don't feed or give medications through the tube.
• Reposition and re-check aspirate pH; repeat imaging with the tip visible, reviewed by a competent person against the four criteria.
• Consider the wider decision - is NG feeding in her best interests (capacity, advance decisions, prognosis)?

3. A 45-year-old man has sudden tearing chest pain radiating to the back. BP 180/100 in the right arm and 140/80 in the left. Chest X-ray shows a widened mediastinum.
Answer: Suspected acute aortic dissection.

• Urgent CT aortogram (a normal chest X-ray doesn't exclude dissection).
• Analgesia, IV beta-blocker (labetalol) to lower heart rate and BP; avoid thrombolysis and antiplatelets until dissection is excluded.
• Type A - immediate cardiothoracic surgery; type B - medical management or TEVAR.

4. A 30-year-old woman is breathless and febrile 2 weeks after starting chemotherapy for breast cancer. Chest X-ray shows bilateral perihilar haziness; SpO₂ 88%.
Answer: Differential - PCP, viral pneumonia, drug pneumonitis, pulmonary oedema, lymphangitis.

• Neutropenic sepsis protocol if neutropenic; oxygen.
• CT chest (and CTPA if PE possible); bronchoscopy with BAL for PCP and viral PCR.
• Early respiratory and oncology input; treat empirically as indicated.

5. A 72-year-old man is breathless. Chest X-ray shows a left pleural effusion. He worked in a dockyard.
Answer: Unilateral effusion - exclude malignancy (mesothelioma, lung cancer).

• Ultrasound-guided diagnostic aspiration - protein, LDH, pH, glucose, cytology, microbiology.
• Contrast CT chest (ideally before full drainage) - pleural thickening, nodularity, mass.
• If cytology is negative and suspicion remains - image-guided or thoracoscopic pleural biopsy; respiratory MDT.

Key Points

• Check the patient, date, projection and RIPE (rotation, inspiration, projection, exposure) first.
• Use a system (ABCDE) and look at the review areas - apices, behind the heart, hila, below the diaphragm, bones.
• Always compare with previous films.
• Silhouette sign - right heart border (RML), left heart border (lingula), diaphragm (lower lobes).
• Collapse shows volume loss; in adults, exclude an obstructing tumour.
• White-out - trachea towards (collapse), away (effusion), central (consolidation).
• Tension pneumothorax is a clinical diagnosis - decompress before imaging.
• Heart failure - alveolar oedema, B lines, cardiomegaly, upper lobe diversion, effusions.
• A normal chest X-ray doesn't exclude lung cancer, PE, heart failure or aortic dissection.
• NG tube - midline, bisects carina, crosses diaphragm in midline, tip below left hemidiaphragm; if in doubt, don't feed.
• CTPA for PE; HRCT for ILD (UIP - basal subpleural honeycombing); CTCA first-line for stable chest pain.
• Low-dose CT lung cancer screening for people aged 55–74 with a smoking history.

Guidelines and Further Reading

• Royal College of Radiologists: iRefer - chest imaging guidance
• BTS: Guideline for pleural disease (2023); BTS pulmonary nodule guidelines (2015); BTS community-acquired pneumonia guidance
• NICE NG12: Suspected cancer - recognition and referral; NHS England: Lung Cancer Screening Programme
• NHS England / NHS Improvement: Patient safety alert - nasogastric tube misplacement; Never Events list
• NICE CG95: Recent-onset chest pain of suspected cardiac origin (CT coronary angiography); NICE NG106: Chronic heart failure
• NICE NG158: Venous thromboembolic diseases (CTPA)
• BNF - for current doses