Thursday April 1, 2010
CXR diagnosis in Pulmonary Embolism
Looking for Westermark’s and Palla’s Signs together

Answer: Chest radiograph showing

Westermark’s sign - focal oligemia in the right lung (area between white arrowheads) and

Palla’s sign - a prominent right descending pulmonary artery (black arrow).

Westermark’s and Palla’s signs in combination are rare but, when seen, can help confirm diagnosis of pulmonary embolism.


Reference: Westermark’s and Palla’s Signs in Acute Pulmonary Embolism - Circulation. 2007;115:e211.http://circ.ahajournals.org/cgi/content/full/115/8/e211