COVID-19 pneumonia: microvascular disease revealed on pulmonary dual-energy computed tomography angiography

{Background: Increased prevalence of acute pulmonary embolism in COVID-19 has been reported in few recent studies. Some works have highlighted pathological changes on lung microvasculature with local pulmonary intravascular coagulopathy that may explain pulmonary artery thrombosis found on pulmonary computed tomography (CT) angiography. The objective of our study was to describe lung perfusion disorders assessed by pulmonary dual-energy CT (DECT) angiography in severe COVID-19 patients. Methods: This single center retrospective study included 85 consecutive patients with a reverse transcriptase-polymerase chain reaction diagnosis of SARS-CoV-2 who underwent a pulmonary DECT angiography between March 16th 2020 and April 22th 2020. Pulmonary DECT angiography was performed when the patient had severe clinical symptoms or suffered from active neoplasia or immunosuppression. Two chest radiologists performed pulmonary angiography analysis in search of pulmonary artery thrombosis and a blinded semi quantitative analysis of iodine color maps focusing on the presence of parenchymal ischemia. The lung parenchyma was divided into volumes based on HU values. DECT analysis included lung segmentation, total lungs volume and distribution of lung perfusion assessment. Results: Twenty-nine patients (34%) were diagnosed with pulmonary artery thrombosis, mainly segmental (83%). Semi-quantitative analysis revealed parenchymal ischemia in 68% patients of the overall population, with no significant difference regarding absence or presence of pulmonary artery thrombosis (23 vs. 35