CT Imaging Features During Disease Progression of 2019 Novel Coronavirus (COVID-19) Pneumonia

Objectives: To describe the characteristics of computed tomography (CT) in patients with 2019 novel coronavirus (COVID-19) pneumonia and their changes during disease progression. Patients and Methods: A total of 96 chest CT scans of 61 pneumonia patients associated with COVID-19 were reviewed to identify CT features associated with the time of symptom onset and the evolution of disease. Results: The initial CTs of 61 patients were obtained during 1 to 11 days after the onset. The main CT pattern of initial CT obtained during 1 - 3 days after the symptom onset was single (7/23, 35%) or multiple ground-glass opacity (GGO, 8/23, 35%). At 4 - 7 days after the symptom onset, the main imaging features were crazy paving GGO mixed with partial consolidation pattern (15/32, 47%). At 8 - 11 days after the symptom onset, the CT images showed consolidation pattern (3/6, 50%). A total of 35 follow up CTs were collected. The mean interval time between each follow up CT was 3 ± 2 days. The CT patterns also changed with the evolution of the disease: the features of GGO manifested at the early stage (1 - 3d). The crazy paving GGO pattern, consolidation pattern and mixed with partial consolidation pattern were found 4 to 14 days after the onset. In the absorption stage (15 - 24d), both density and extent of lesions were reduced. Conclusion: The CT imaging features are associated with the time of symptom onset and evolution of disease. Understanding the imaging characteristics of each stage is very helpful for understanding the development of disease.