Score standard for evaluation secondary pulmonary lobular structure
Secondary pulmonary lobular structure scores for all confirmed cases which include lobular size sign (1 score), fusion lobular sign (1 score), interlobular septal thickening sign (1 score), intralobular interstitial thickening sign (1 score) and intralobular vascular thickening sign (1 score).Two senior radiologists with more than 10 years of experience each independently based on the imaging signs of secondary pulmonary lobular structure and assessed all the cases which include confirmed cases of COVID-19 (typical,atypical and multi-stage ) and confirmed cases of non-COVID-19.
Statistic analysis
Statistical analyses were performed with the SPSS software (version 22.0, IBM).Count index was presented as percentage, and all data were presented as means and standard deviation (mean±SD). Independent sample t-test or Chi square test was used. Inter-observer agreement for the subjective image quality was estimate using kappa statistic. P <0.05 was considered statistically significant.