Statistical analysis
Statistical analysis was performed using IBM SPSS Statistics for Windows, Version 25.0 (IBM Corp.). Continuous data conforming to normal distribution expressed by mean ± standard deviation; for those not conformed (median, P25, p75) were listed. Intragroup correlation coefficient (ICC) was used to test the consistency of TSS scores of two observers, ICC values < 0.4, 0.4~0.75, and > 0.75 represent poor, moderate, and good repeatability, respectively. The distribution balance of involved lobes and the number of involved lobes in different clinical types were compared by chi-squared test or Fisher exact test when sample sizes were small and by analysis of variance tests. Wilcoxon-rank test was used for comparison of TSS among different clinical types, since TSS did not conform to the normal distribution. ROC was used to test the differential diagnosis ability of TSS in common-type group and severe-critical-type group.