Differentiation of Acute and Chronic Thromboembolism.
Acute and chronic thromboembolism commonly coexist.
Differential Diagnosis Mean attenuation in chronic PE (87 HU ± 30) is higher than acute PE (33 HU ± 15). Dilated bronchial arteries. Nonobstructive eccentric filling defect forms obtuse angles with the vessel wall. Nonobstructive eccentric filling defect forms acute angles with the vessel wall. Decreased Diameter of pulmonary artery. Increased Diameter of pulmonary artery. Chronic PE Acute PE
Evolution of chronic occlusive pulmonary thromboembolism from acute embolism in a 40-year-old man.
Axial contrast-enhanced CT scan shows acute embolism in the left lower lobe, with increased arterial diameters (arrows) due to impacted thrombi.
Axial contrast-enhanced CT scan obtained at the same level as a, 1 year later, when the patient presented with dyspnea, shows a permanent reduction in the diameters of the left lower lobe arteries (arrows) because of thrombus organization and retraction, findings indicative of chronic thromboembolism.