Background: Chest CT is important for the diagnosis of Corona Virus Disease 2019, which is caused by SARS-CoV-2 via the receptor angiotensin-converting enzyme 2. This study aimed to present special chest CT changes in the detection and management of COVID-19.
Methods: From February 20 to March 6, 2020, clinical data and chest CT of patients with COVID-19 being treated by the Hubei Medical Team were retrospectively analyzed with a time-interval of 2 weeks. In addition, the expressions of ACE2 in different parts of the respiratory system were detected by immunohistochemical staining to explain the special chest CT features of COVID-19 by ACE2 expression.
Results: Of 58 patients, the main respiratory manifestations were fever and cough. Spherical or patchy GGO was the initial CT manifestation of COVID-19 pneumonia. CT findings manifested as rapid evolution from focal unilateral to diffuse bilateral ground-glass opacities (GGO) that progressed to or co-existed with consolidations in chest CT scans. Lung consolidation increased as the disease progressed, accounting for 63.2%, 76.3%, and 87.5% in group 1 (disease course with 0 - 2 weeks), group 2 (2 - 4 weeks), and group 3 (> 4 weeks). Fibrous lesions (72.3%), high density vascular shadow (69.2%), reticular pattern (63.1%), and subpleural parallel sign (61.5%) were common signs of chest CT of COVID-19. IHC results showed that ACE2-expression in the pulmonary alveoli was significantly higher than that in the bronchial mucosa and pleura (p < 0.001).
Conclusions: The special change of CT features in the lung of COVID-19 pneumonia patients have a connection with ACE2 expression patterns in the respiratory system.