Objective:To explore the efficacy of quantitative parameters of dual-layer spectral CT in preoperative prediction of Ki-67 expression in esophageal squamous cell carcinoma (ESCC).Methods:From December 2021 to December 2022, 64 patients with histopathologically diagnosed ESCC were retrospectively analyzed at Liaoning Cancer Hospital & Institute. The expression level of Ki-67 in ESCC tumor tissue was detected by the immunohistochemical method. The patients were divided into the Ki-67 high expression group (the Ki-67 expression index≥30%, 47 cases) and the Ki-67 low expression group (the Ki-67 expression index<30%, 17 cases). The quantitative parameters of spectral CT were measured, including traditional 120 kVp CT value, 40 keV CT value, iodine density (ID), normalized iodine density (NID), and Z-effective in arterial and venous phases. Independent sample t test was used to compare the differences in the parameters between the Ki-67 high and low expression groups. The receiver operating characteristic (ROC) curve was drawn to evaluate the efficacy of each parameter in predicting Ki-67 expression. DeLong test was used to compare the area under the curve (AUC). Results:The 120 kVp CT value, 40 keV CT value, ID, and Z-effective in the arterial phase and the 120 kVp CT value, 40 keV CT value, ID, NID, Z-effective in venous phase in the Ki-67 high expression group were all higher than those in the Ki-67 low expression group ( P<0.05). There was no statistically significant difference in arterial phase NID between the two groups ( t=1.85, P=0.070). NID in the venous phase had the highest AUC in predicting high expression of Ki-67 in ESCC (AUC=0.965, 95%CI 0.923-1.000). With a venous phase NID value of 0.28 as the diagnostic threshold, the sensitivity and specificity were 93.6% and 100%. There was no significant difference in AUC between venous phase NID and venous phase ID (AUC=0.926) and Z-effective (AUC=0.909) ( Z=-1.52, 1.81, P=0.128, 0.071), but there was a significant difference of AUC between venous phase NID and 120 kVp CT value (AUC=0.719) and 40 keV CT value (AUC=0.747) ( Z=3.41, 3.30, P=0.001, 0.001). There were statistical differences of AUC between venous phase NID and each parameter of arterial phase ( P<0.05). Conclusion:The three spectral CT parameters (ID, NID, and Z-effective) in the venous phase have high diagnostic efficacy in predicting ESCC Ki-67 expression.

Objective: To evaluate the current status and related factors of influenza vaccination among health care workers (HCWs) in tertiary hospitals of Xining city after the implementation of the free influenza vaccination policy. Methods: In August 2018, the cluster sampling method was used to select four medical institutions in Xining that had previously conducted investigations and interventions. All HCWs(excluding logistic staff) in each medical institution were included in the study. A total of 3 260 valid respondents were included. Questionnaires were used to collect the demographic characteristics, influenza and influenza vaccination awareness, implementation of free policy in the influenza epidemic season from 2017 to 2018, influenza vaccination status, awareness of influenza vaccination schedule and free policy. The multivariate logistic regression model was used to analyze related factors of influenza vaccination. Results: The age of respondents was (31.41±5.00) years. The influenza vaccination rate was 6.80% (226/3 260) in 2017-2018 influenza epidemic season. After controlling for related factors, the awareness of the influenza vaccination schedule (OR=17.05, 95%CI: 5.86-49.59), vaccination frequency (OR=8.22, 95%CI: 2.98-22.61) and the free policy (OR=3.15, 95%CI: 1.49-6.67) had higher vaccination rate. Conclusion The influenza vaccination rate of HCWs in tertiary hospitals of Xining city was low. Increasing the awareness of the vaccination schedule, frequency and free policy may promote the influenza vaccination rate of HCWs.