Westermark sign (lungs)

Dr Henry Knipe et al.

Westermark sign is a sign of pulmonary embolus (PE) seen on chest radiographs.

Along with Fleishner sign and Hampton hump, it makes one of the three described signs of pulmonary embolus on chest radiographs.

In one study (PIOPED) this sign was present on ~10% of chest x-rays of patients with confirmed PE 2

The theory behind the sign is either obstruction of the pulmonary artery or distal vasoconstriction in hypoxic lung 3

Radiograph
  • focal peripheral hyperlucency secondary to oligaemia 2, 3, 4
  • central pulmonary vessels may also be dilated 3

Dr. Nils Westermark (1892-1980) was a Swedish radiologist who first described this sign 5.

Chest x-ray
Share article

Article information

rID: 29066
Systems: Chest, Vascular
Section: Signs
Tag: pe
Synonyms or Alternate Spellings:

Support Radiopaedia and see fewer ads

Cases and figures

  • Drag
    Case 1: left-sided
    Drag here to reorder.
  • Drag
    Case 2
    Drag here to reorder.
  • Updating… Please wait.
    Loadinganimation

    Alert accept

    Error Unable to process the form. Check for errors and try again.

    Alert accept Thank you for updating your details.