radiological appearance in pulmonary embolism
Last reviewed 01/2018
The plain chest radiograph is better for demonstrating peripheral emboli. The appearances may however be as follows:
- in central emboli - oligaemic lung fields.
- peripheral emboli - linear, or sometimes wedge-shaped, shadows may be seen
The appearances of a pulmonary embolus on a plain chest radiograph are sometimes referred to as Westermark's triad.
Other changes that may occur include an elevated diaphragm, some segmental or lobar volume loss, and small effusions (exudate - usually haemorrhagic). Secondary infection of infarcted lung causes cavitation.
Note that it may be difficult to distinguish pulmonary embolism from infection on a chest radiograph.