Westermark’s Sign

Other Known Aliases – none

Definition – focal peripheral hyperlucency resulting from collapsed vessels distal to a pulmonary thromboembolism.

Clinical Significance – Occurs as a result of oligemia of perfusion to the lung parenchyma and can be seen in up to 10% of patients with acute PTE.  Similar to Hampton’s Hump, it has a low sensitivity, but a high specificity

History – Named after Nils Johan Hugo Westermark (1892-1980), a Swedish radiologist who first described this finding in his 1938 paper entitled ” On the roentgen diagnosis of lung embolism”.  He was also an accomplished sailor and won a silver medal in the 1912 Olympics.

References

1. Firkin BG and Whitwirth JA.  Dictionary of Medical Eponyms. 2nd ed.  New York, NY; Parthenon Publishing Group. 1996.
2. Bartolucci S, Forbis P.  Stedman’s Medical Eponyms.  2nd ed.  Baltimore, MD; LWW.  2005.
3. Yee AJ, Pfiffner P. (2012).  Medical Eponyms (Version 1.4.2) [Mobile Application Software].  Retrieved http://itunes.apple.com.
4. Whonamedit – dictionary of medical eponyms. http://www.whonamedit.com
5. Up To Date. www.uptodate.com
6. Krishnan AS, Barrett T. Images in clinical medicine. Westermark sign in pulmonary embolism. NEJM. 2012; 366(11):e16. [pubmed]
7. Radiopaedia.  Westermark Sign. https://radiopaedia.org/articles/westermark-sign-1
8. Westermark N. On the roentgen diagnosis of lung embolism. Acta Radiol 1938;19:357‑72.