COVID-19: A review of what radiologists need to know

Table 1 Imaging manifestations of coronavirus disease-2019 on chest computed tomography

Stage	Chest CT findings	Pathology
Early stage (0-4 d after symptom onset)	Ground-glass opacity and reticular pattern (44%-93%), consolidation (7%-17%)	Interstitial edema and thickening as the result of inflammatory infiltration
Advanced stage (5-8 d after symptom onset)	GGO and reticular pattern (81%-88%), “crazy-paving” pattern, consolidation in unilateral or bilateral lungs (15%-55%)	Edematous thickening of interstitial structures and interlobular septa; partial collapse of alveolar space; viscous and fibrinous exudate in alveolar space with hyaline membrane formation
Severe stage (9-13 d after symptom onset)	GGO (33%-57%), diffuse patchy consolidation (33%-60%) of both lungs, vascular enlargement sign, bronchial wall thickening and bronchiectasis; white lung	Alveolar proteinaceous and viscous exudate mixed with cellular debris, blood products and fibroblast plugs; injury of the endothelial cells of the small blood vessels with consequent thrombosis; bronchiolar dilatation and wall thickening
Absorption stage (14 d later after symptom onset)	The density of the consolidation was gradually reduced with a decrease in the volume of lesion opacities; some fibrous streaks and reticular shadows may persist	Infiltrative and exudative lesions were absorbed with some remaining fibrous proliferation and focal fibrosis

CT: Computed tomography; GGO: Ground glass opacities.