Halo sign (chest)

The halo sign (HS) in chest imaging is a feature seen on lung window settings (typically HRCT), ground glass opacity surrounding a pulmonary nodule or mass and represents haemorrhage. It is typically seen in angioinvasive aspergillosis.

Histopathologically, it represents a focus of pulmonary infarction surrounded by alveolar hemorrhage.

Other entities that may give a halo sign include:

Infectious disease
Neoplasia
Non-neoplastic, non-infectious, inflammatory diseases
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Article Information

rID: 8702
System: Chest
Section: Signs
Synonyms or Alternate Spellings:
  • CT halo sign
  • Halo sign in chest imaging
  • Thoracic CT halo sign
  • Halo sign in CT chest imaging

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    Angioinvasive asp...
    Figure 1: angioinvasive aspergillosis - gross pathology
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    Aspergillus lung ...
    Case 1: halo sign with angioinvasive aspergillosis
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    Case 2: with peritumoural haemorrhage
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    Case 3: rectal cancer metastasis
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