Pulmonary opacities on chest x-ray


There are 3 major patterns of pulmonary opacity:

  • Airspace filling
  • Interstitial patterns
  • Atelectasis


1. Airspace filling

  • Localized = segmental
  • Diffuse or multifocal

2. Interstitial patterns

  • Reticular—fine or coarse linear shadows
  • Reticulonodular
  • Nodular—small (2 to 3 mm), medium, large, or masses (>3 cm)

3. Atelectasis

  • Diminished aeration of lung
  • Associated with signs of volume loss

Causes of pulmonary opacity

Focal airspace disease

  • Pneumonia
  • Pulmonary embolism: infarction or intrapulmonary hemorrhage
  •  Neoplasm: alveolar cell carcinoma, lymphoma (usually diffuse)
  • Atelectasis: opacity accompanied by signs of volume loss

Diffuse or multifocal airspace disease

  • Pulmonary edema: CHF and non-cardiogenic pulmonary edema
  • Pneumonia: bacterial, viral, Mycoplasma, Pneumocystis
  • Hemorrhage: trauma (contusion), immunologic (Goodpasture’s), bleeding diathesis, pulmonary  embolism
  • Neoplasm: alveolar cell carcinoma, lymphoma
  • Desquamative interstitial pneumonitis (DIP), alveolar proteinosis
  • Bat-wing pattern—Central opacification with peripheral clearing—characteristic of pulmonary edema

Fine reticular pattern


  • Interstitial pulmonary edema
  • Interstitial pneumonitis: viral, Mycoplasma
    (Airspace filling often accompanies interstitial pneumonia and pulmonary edema)


  • Lymphangitic metastasis, sarcoidosis, eosinophilic granuloma, collagen vascular diseases, inhalation injuries, idiopathic pulmonary fibrosis (“fibrosing alveolitis”), resolving pneumonia

Coarse reticular pattern

  • Honeycomb lung—end-stage pulmonary fibrosis
  • Also seen when pneumonia or pulmonary edema occurs in patients with underlying emphysema

Reticulnodular pattern

  • A common radiographic pattern that encompasses the same disorders as reticular patterns

Miliary pattern — 2 to 3 mm well-defined nodules (“micronodular pattern”)

  • Tuberculosis, Fungal, Nocardia, Varicella
  • Silicosis, Coal Worker’s lung, Sarcoidosis, Eosinophilic granuloma
  • Neoplastic (adenocarcinoma, thyroid)

Nodular pattern — Margins of the lesions are generally well-defined. Mass: >3 cm

  • Neoplasm: metastatic, lymphoma; benign tumors
  • Fungal or parasitic infection, septic emboli
  • Rheumatoid nodules, Granulomatosis With Polyangiitis (Wegener granulomatosis)

CCC 700 6

Critical Care


Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of three amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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