Chest CT Features of Patients with COVID-19 Pneumonia Following Hospital Discharge

Objective: To evaluate chest computed tomographic (CT) findings in patients with coronavirus disease 2019 (COVID-19) pneumonia following hospital discharge. Methods: 52 patients with confirmed COVID-19 pneumonia underwent follow-up chest CT. The scans were obtained on average 43.1 days after hospital admission and analyzed for parenchymal abnormality (e.g., ground-glass opacities, consolidation, or interstitial thickening) and evidence of fibrosis (e.g., assigned to one of three groups: Group 1 (normal lung), Group 2 (parenchymal abnormality but without evidence of fibrosis), and Group 3 (evidence of fibrosis)). Clinical data and CT manifestations of the patients were compared among the three groups. Results: 30.8% (16/52) of patients with COVID-19 pneumonia showed normal lung and were designated as Group 1. 69.2% (36/52) of patients showed parenchymal abnormality ranging from residual ground-glass opacities, consolidation, or interstitial thickening in Group 2 (51.9%) to fibrosis in Group 3 (17.3%). All patients in Group3 had severe/critical COVID-19, while most patients in Group 2 and Group 1 had common COVID-19. Patients in Group 3 were older (60.9 vs. 40.8 and 36.8 years, p<0.001, there is a significant difference), had a longer hospitalization day (20.2 vs. 15.3 and 12.3 days, p<0.05, there is a significant difference), a higher ratio of patients with comorbidities (88.9%vs14.8% and 25%, p<0.001, there is a significant difference), and higher peak CT scores (13 vs. 6.2 and 3.2, p<0.001, there is a significant difference) than those patients in Group 2 and Group 1. Conclusions: Elderly severe/critical COVID-19 patients with comorbidities are more prone to develop fibrosis early on following hospital discharge. On the other hand, lung inflammation in younger patients with common COVID-19 can be resolved completely.