ANALYSIS OF BASELINE CT FINDINGS AND EVOLUTION OF SINGLE LESION IN THE EARLY STAGE OF COVID-19

Lingyan Zhou^{1, #}, Qinxiang Mao^{2, #}, Jiawei Li³, Xiaolu Huang³, Huili Yu³ and Xunhua Xu^{3, *}

¹Department of Radiology, The Second Hospital of Wuhan Iron and Steel Company, Wuhan, 430085, China - ²Department of Radiology, Liuzhou People’s Hospital, Liuzhou, 545003, China - ³Department of Radiology, China Resources & WISCO General Hospital Affiliated to Wuhan University of Science and Technology, Wuhan, 430080, China 

Background: COVID-19 is currently the most concerned epidemic in the world. We conducted a CT follow-up study of a single lesion in the early stage to provide imaging basis for clinicians to accurately diagnose and evaluate the prognosis of COVID-19.

Methods: Seventy patients with COVID-19 diagnosed in The Second Hospital of Wuhan Iron and Steel Company were retrospectively analyzed. With the first detection of early single lesion as the baseline lesion, the average interval between 4 follow-up and baseline CT was divided into four stages. The signs of the baseline lesions and their changes in the four stages were analyzed, and their evolution was summarized. 

Results: We found that most of the baseline lesions were ground-glass opacities (GGO) with subpleural distribution in the lower lobe of the lungs among the 70 patients, and CT signs were different at different stages. In the first stage, baseline lesions progressed in 54 cases (77%) and new lesions were found in 36 cases (51%) . No progressive lesions and new lesions were found in the third stage. In the first three stages, the proportion of fine reticulation decreased gradually, while the proportion of crazy paving pattern and thin GGO gradually increased. Fifty-four cases (77%) were complicated with consolidation, which accounted for the highest proportion in the second stage. After consolidation, the absorption of lesions became slower and the course of disease prolonged. Twenty-two cases (31%) progressed to multiple lesions of the single lobe, and 32 cases (46%) involved both lungs. Single lesion and multiple lesions of single lobe were more easily absorbed than bilateral lung lesions. We also found that patients over 50 years old tend to involve both lungs and the course of disease is relatively longer. 

Conclusion: The CT imaging features of COVID-19 at different stages can be used to evaluate the progression of the disease.