Temporal Changes of CT Findings between Non-emergency and Emergency Patients with COVID-19 Pneumonia: A Multi-centered, Retrospective, Longitudinal Study

Abstract

Objective: To analyze the differences between clinical evaluation and the detailed imaging features in the time course of lung changes in diverse clinical types.Methods: 73 patients with COVID-19 pneumonia were retrospectively collected from three institutions in China. Radiographic features, CT score were analyzed and compared between non-emergency group (mild- and common-type) and emergency group (severe- and fatal-type).Results: In non-emergency group, the disease slowly aggravated within the first two weeks, peaked during the 2nd week (median superimposed involvement CT score: 9.5), while in emergency group, the disease peaked in the 2nd week rapidly, and the superimposed involvement CT score(median: 20) was higher than that in non-emergency group. Both two groups began to decline in the 4th week, and persistence of high levels. In emergency group, the residual lung lesions were mostly reticular (median single reticular CT score: 10) and consolidation (median single consolidation CT score:7). By contrast, most residual lung lesions in non-emergency group were GGO (median single GGO CT score: 7) and reticular (median single reticular CT score: 4). In both non-emergency and emergency groups, GGO pattern was dominant in the first week, and the proportion in emergency group was higher [20 (65%) and (18 (72%), respectively], the consolidation pattern peaked in the second week, which were 9 (32%) and 19 (73%), respectively, reticular pattern became dominant in and after 4 weeks (both over 40%).Conclusion: The disease in non-emergency and emergency group peaks in the second week. In the non-emergency group, the residual lesions are dominated by GGO and reticular, while those in the emergency group are mainly reticular and consolidation. The transiently CT manifestations of emergency and non-emergency follow certain patterns at different time points of the disease course.