Septal lines - Example 1

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Septal lines - Example 1

  • Pulmonary oedema may manifest with evidence of interstitial oedema (septal lines) or alveolar oedema (airspace shadowing/consolidation)
  • Septal lines (also known as ‘Kerley B lines’) appear as horizontal lines which make contact with the edge of the lung
  • Airspace shadowing due to alveolar oedema is also visible (see next page)

Septal lines - Example 2

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Septal lines - Example 2

  • Septal lines represent thickening of the interlobular septa – interstitial tissue which separates the secondary lobules at the peripheries of the lungs
  • Septal lines are a specific sign of interstitial oedema in the context of suspected left ventricular failure
  • Occasionally septal lines are seen in conditions which cause blockage of the pulmonary lymphatics – such as lymphangitis carcinomatosa or sarcoidosis

Septal lines - Example 3

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Septal lines - Example 3

  • Septal lines may be very subtle but if present are a clear indicator of interstitial oedema
  • Look carefully at the lung bases near the costophrenic angles whenever heart failure is suspected clinically
  • Septal lines may be present with or without alveolar oedema

Page author: Salisbury NHS Foundation Trust UK (Read bio)

Last reviewed: October 2019