Case submitted/via our partner RiT.
Axial CT image shows a partial thrombus (stars) in the main and proximal left pulmonary artery that forms an obtuse angle with the vessel wall. There is enlarged pulmonary artery and bronchial collaterals (arrows).


* Some pulmonary emboli do not resolve and form endothelialized fibrosis of pulmonary vascular bed, thought to be due to disturbance in thrombus resolution
* Results: pulmonary HT, cor pulmonale, bronchial hypertrophy


* Multiple episodes of PE
* Younger age
* Larger perfusion defect
* Idiopathic cause of PE

CT signs

* Complete thrombus with small vascular diameter
* Partial crescent-shaped, eccentric thrombus
* Calcified thrombus
* Web, band
* Pulmonary hypertension
* Collaterals from bronchial arteries
* Mosaic attenuation of the lungs

Castaner E, et al. CT diagnosis of chronic pulmonary thromboembolism. Radiographics 2009;29:31-50.