Imaging findings of CT pulmonary angiography in patients with chronic thromboembolic pulmonary hypertension

Abstract

Objective: To investigate the imaging findings of CT pulmonary angiography (CTPA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH). Methods: Consecutive CTEPH cases admitted to receive CTPA in China-Japan Friendship Hospital from December 2015 to December 2019 were enrolled with prospective data collected. The medical histories, imaging manifestation and hemodynamic parameters were analyzed. Patients were divided into proximal lesions group and distal lesions group according to the site of thrombus, and imaging findings were compared between these two groups. Results: In 135 cases of CTEPH, CTPA showed thrombus in both lungs in the majority of patients (133 cases, 98.5%) with location of thromboembolic disease in level Ⅰ, Ⅱ and Ⅲ for most patients, only 8 cases with level Ⅳ(7.3%) and no level 0 patients. The most common signs of chronic thrombus were vessel cutoffs (134 cases, 99.3%), eccentric wall-adherent filling defects (111 cases, 88.2%), web or bands (80 cases, 59.3%), stenosis (41 cases, 30.4%). Compared to patients with distal lesions, eccentric wall-adherent filling defects, irregular vessel wall were more common in patients with proximal lesions, stenosis was more common in distal lesions, all P<0.05. The most common lung parenchymal signs were mosaic attenuation (104 cases, 77.0%), and pulmonary infarction (79 cases, 58.5%). Pulmonary infarction included pleura-based consolidation opacity (35/79, 44.3%), linear opacities (23/79, 29.1%), or both (13/79, 16.5%). Pulmonary artery enlargement (132 cases, 97.8%) and right ventricular hypertrophy (130 cases, 96.3%) were common, other signs included contrast reflux into the inferior vena cava (70 cases, 51.9%), enlargement of bronchial arteries (68 cases, 50.3%). No differences were found for all the secondary signs between patients with proximal lesions and those with distal lesions, all P>0.05. Conclusions: Vessel cutoffs, eccentric wall-adherent filling defects, web or bands are the most common CTPA findings of chronic thrombus in CTEPH. Secondary signs include mosaic attenuation, pulmonary infarction, pulmonary artery enlargement, right ventricular hypertrophy and enlargement of bronchial arteries. Eccentric wall-adherent filling defects are more common in patients with proximal lesions than those with distal lesions.