Home

Recent Notes

Chest X-Ray Interpretation

Feb 17, 20244 min read

Note for this page

All of the images will have no pathology unless indicated otherwise

Quick check

1. Patient details

  • Name, DoB
  • When the CXR was taken
  • Where it was taken
  • Any previous images for that patient

2. Quality of image - RIPE

Rotation

  • The medial parts of the two clavicles should be equal distance from the spine
  • Spinous processes should be vertical

Inspiration

  • 5 to 7 anterior ribs or at least 9 posterior ribs
  • Inspiratory effort could be gauged
  • Poor inspiration can mimic cardiomegaly
  • Crowding of vessels at the base of the lungs can mimic consolidation or collapse and often occurs in acutely unwell patients

Projection

  • AP/PA?
  • Most CXR are PA as AP misrepresent the size of the heart (too large)
  • Can tell if AP if scapulae projected over lung fields

Exposure

  • Correct definition and quality in image.
  • Can tell if can see vertebrae behind the heart

3. Clinical findings - ABCDE

Airway

  1. Trachea
  2. Carina and bronchi
    • Right bronchus is straighter and wider than the left risk for aspiration
  3. Hilar regions
    • Check for abnormal vessels, or enlarged lymph nodes
    • Right hilar should always be higher than left
    • Bilaterally enlargement suggests Tuberculosis or Sarcoidosis
    • If unilateral think Lung Tumours

Breathing

Zones are used instead of lobes when localising a lesion

Lack of any lung markings pneumothorax

Pleura are only visible if they become thickened or fluid accumulates (e.g. mesothelioma)

Lung opacities are described as nodular, reticular (network of fine lines, interstitial) or alveolar (fluffy). A single nodule may be called a space-occupying lesion

Nodules - if >3cm across it becomes a pulmonary mass

  • Neoplasia: metastases, lung cancer, hamartoma, adenoma
  • Infections: varicella pneumonias, septic emboli, abscess, hydatid
  • Granulomas: Tuberculosis, Sarcoidosis, histoplasmosis
  • Pneumoconiosis (except asbestosis)

Reticular opacification - lung parenchymal changes

Alveolar opacification - can be due to any material filling the alveoli

  • Pus - pneumonia
  • Blood - haemorrhage, DIC
  • Water - heart, renal or Liver failure, ARDS, smoke inhalation, heroin, toxicity, near drowning
  • Cells - Lymphoma, adenocarcinoma
  • Protein - alveolar proteinosis, ARDS, fat emboli

Ring opacities - either from a CT cross section referring to bronchiectasis/bronchitis or cavitating lesions on CXR

Linear opacities - septal lines (Kerley B lines, i.e. interlobular lymphatics seen with something), atelectasis, pleural plaques

White out of whole hemithorax - pneumonia, large Pleural Effusion, ARDS, post pneumonectomy

Cardiac

  • Should be less than 50% of the overall thoracic window
  • Boarders should be clearly defined - usually consolidation would change this
  • Consolidation of the lingula blurs the left heart boarder
  • 1/3 should lie to the right of the vertebral column, 2/3 to the left
  • May appear elongated if the chest is hyperinflated COPD or enlarged in AP or if there is LV failure or pericardial effusion

Diaphragm

  • The right side is often slightly higher due to liver
  • Costophrenic angles should be well defined and acute
  • Blunting can be caused by hyperinflation of fluid collections

Everything

  • Damage to bony structures
  • Dislocations
  • Lytic lesions
  • Presence of extra features - double left heart boarder (left lower lobe collapse)
  • Breast shadows or lack of them
  • Artificial shadows: wires/leads/tubes/artificial valves/pacemakers/past sternotomy

Examples of pathological scans

Lobar pneumonia (typical Strep. pneumoniae)

Atypical pneumonia (mycoplasma)

Aspiration pneumonia (can move depending on position)

Tuberculosis

Ghon lesion - left middle lobe Calcified lymph nodes

Miliary tuberculosis

Uncontrolled haematogenous spread

pneumothorax

Hydropneumothorax

Pneumomediastinum

Lobar collapse

Right middle zone collapse - loss of RHB and in lateral view

Sail sign - left lower lobe collapse

Pleural Effusion

pneumonectomy (no mass effect - volume loss)

Massive Pleural Effusion (with mass effect)

COPD
  • Flattened diaphragm
  • More anterior ribs seen
  • May see floating heart sign
  • Bullous emphysema

Heart Failure
  • Alveolar oedema - bat wing opacities in middle
  • (Kerley) B lines - thickened interlobular septum which extend inwards. Horizontal line that extends to the periphery
  • Cardiomegaly
  • Dilated upper lobe vessels
  • Pleural Effusion

Hiatus hernia

Lung Tumours

Cannonball mets - from primary breast cancer Pancoast tumour Horner’s Syndrome

Check ribs for invasive lesion

Graph View

Backlinks