Table 2. CT pulmonary angiography imaging findings in chronic thromboembolic pulmonary hypertension.

Chronic thromboembolic pulmonary hypertension signs	CTPA imaging findings
Vascular signs	Complete occlusion—vessel cutoff;
	Partial occlusion—webs, bands, focal stenotic vessel segment and areas of post-stenotic dilatation, irregular thickening of the vessel wall and reduced caliber, calcified residual thrombus, peripheral crescent-shaped defect
Collateral vessels	Bronchial artery dilation (> 2 mm) and tortuosity;
	Non-bronchial arteries: pleural, intercostal, phrenic, internal mammary
PH signs	Main pulmonary artery dilation (> 33 mm);
	Ratio main pulmonary artery diameter to ascending aorta diameter >1.1:1;
	Right ventricle enlargement and hypertrophy;
	Ratio right ventricle diameter to left ventricle diameter >1:1;
	Bowing of the interventricular septum toward the left ventricle;
	Right ventricular hypertrabeculation/hypertrophy
Lung parenchymal signs	Scars from prior pulmonary infarctions: bands, irregular peripheral linear opacities, wedge-shaped opacities with pleural thickening;
	Mosaic lung attenuation

CTPA, computed tomography pulmonary angiography; PH, pulmonary hypertension.