Pulmonary embolism Acute vs Chronic

Pulmonary embolism

	Acute	Chronic
1	Central luminal defect ‘donut sign’	Peripheral mural defect
2	Filling defect forming acute angle with arterial wall	Filling defect forming obtuse angle with arterial wall
3	Pulmonary infarction (33%) - Subpleural consolidation, atelectasis, effusion, cavitation - More common in right lower zone	Presence of recanalisation / collateral formation Peripheral arterial pruning / narrowing
4	Asymmetric oligaemia (Westermark’s sign)	Mosaic attenuation
5	Complete vessel occlusion
6	Atelectasis, wedge shape opacities
7	Enlarged pulmonary arteries

Westermark’s sign: Oligaemia

Fleischer’s sign: Prominent pulmonary artery

Hampton’s hump: Wedge shape lung infarct


Acute pulmonary embolism
Arrowed: Filling defect centrally surrounded by contrast = Donut sign

Acute pulmonary embolism in MIP (Maximum Intensity Projection)
Arrowed: Filling defect located centrally in the lumen