Assessment of pulmonary hila on chest x-ray (approach)

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The assessment of the pulmonary hila on chest x-ray is important for detecting potential mediastinal and lung pathology.

Several features of the hilum and hilar point can be assessed:

  • shape
    • normally appear as K or C-shapes on either side
    • contents: pulmonary arteries and veins, bronchi, lymph nodes
  • position
    • left hilum is normally 1-2 cm higher than the right
    • low left/right hilum could mean that it is either displaced, usually due to volume loss in atelectasis
  • size
    • vascular enlargement: appear like "elephants trunks", typically bilaterally enlarged
    • nodal enlargement: appears craggy; maybe due to rotation or skeletal abnormality (e.g. scoliosis)
    • an apparent hilar mass may not be hilar in origin (see: hilum overlay sign)
  • change: for any suspected pathology, comparison to previous imaging is the first step to further evaluation
  • density: pathological hila are often more dense/solid