In order to establish a method for the detection of serum antibodies to donkey-derived e-quine coronavirus(ECoV),recombinant ECoV N protein was expressed in E.coli system,purified by nickel column affinity chromatography and identified by Western blot.After optimizing the re-action conditions,the indirect ELISA(iELISA)detection method was established using the puri-fied recombinant protein as coating antigen and used to detect 143 clinical serum samples.The re-sults showed that the recombinant N protein,which has good reaction activity with serum antibod-y,was successfully expressed.The optimum conditions of the established iELISA method were as follows:the amount of antigen coated was 0.2 μg/well and overnight at 4 ℃,10％skimmed milk powder solution was sealed at 37℃ for 1.5 h,the dilution concentration of serum was 1∶200,and the enzyme-labeled secondary antibody diluted at 1∶10 000.The sensitivity test results showed that the positive serum could be diluted to 1∶6 400.The specificity test results showed that all an-tibodies to several donkey pathogens were negative.The repetitive test results showed that the in-tra-and inter-batch coefficients of variation were 2.90％-6.12％and 2.29％-7.88％respectively.The positive rate of clinical donkey serum was 57.3％.The iELISA established in this study pro-vides a technical support for epidemiological investigation and antibody surveillance.

Objective:To investigate the feasibility of ultra-low dose (ULD) CT pulmonary angiography (CTPA) combined with deep learning reconstruction (DLR) in the diagnosis of pulmonary embolism (PE).Methods:This cross-sectional study prospectively enrolled 100 patients with suspected PE who underwent CTPA examination in Zhongshan Hospital Fudan University, and Shanghai Geriatric Medical Center from April to July 2024, and were randomly divided into the routine dose (RD) group and ULD group according to block randomization. Effective dose (ED) were calculated. The noise index of RD group and ULD group was set to 10 and 20, respectively. Other scanning parameters and contrast agent injection protocol were the same. The CT images of RD group were reconstructed using hybrid iterative reconstruction (HIR), while ULD images were reconstructed with HIR and DLR (ULD-HIR subgroup and ULD-DLR subgroup). The image quality of the three groups of images was subjectively evaluated (overall image noise, pulmonary artery display) and objectively evaluated [signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) of the images] respectively. Finally, the diagnostic results of PE by the expert committee composed of three chief physicians were taken as the gold standard, and one physician with lower qualifications independently evaluated the diagnostic rate of PE in the three groups of images. Objective image quality parameters across the three groups were compared using ANOVA, with LSD post hoc test was used for multiple comparisons. Subjective scores among the three groups were analyzed using the Kruskal-Wallis H test, with Bonferroni corrected pairwise post hoc test was applied for multiple pairwise comparisons. Results:The ED in the RD group and ULD group were (2.7±0.5) mSv and (0.7±0.2) mSv, respectively, and the differences were statistically significant ( t=26.42, P<0.001). The overall differences in CT values of pulmonary arteries at all levels in the images of the RD group, the ULD-HIR subgroup, and the ULD-DLR subgroup were not statistically significant ( P>0.05).The RD group, ULD-HIR subgroup and ULD-DLR subgroup overall differences in SNR and CNR at all levels pulmonary arteries were statistically significant ( P<0.001), in which except for the differences in CNR and SNR values of the left pulmonary arterial trunk in the RD group and the ULD-HIR subgroup, and SNR values of basal segment pulmonary artery of the lower lobe of the left lung, which were not statistically significant ( P>0.05), the differences of the rest of the indexes in the pairwise comparisons between the groups were statistically significant ( P<0.05). The overall differences in the subjective scores of image pulmonary vascular display and image noise in the RD group, ULD-HIR subgroup and ULD-DLR subgroup were statistically significant ( P<0.001), except that the differences in the subjective scores of image pulmonary vascular display in the ULD-DLR subgroup were not statistically significant when compared with that of the RD group ( P>0.05) and that of the rest of the metrics in the between-groups two-by-two comparisons were all statistically significant ( P<0.05). The difference in diagnostic rates of PE in the pulmonary artery trunk, lobe and segmental levels in the images of the RD group, ULD-HIR subgroup and ULD-DLR subgroup was not statistically significant ( P>0.05). Conclusions:DLR can significantly reduce the radiation dose of CTPA examination. Even at ultra-low radiation dose, its image quality is still better than HIR reconstruction at conventional doses and preserve diagnostic accuracy of PE at the lobe level and segment level.

Objective To investigate the value of flexible subtraction CE-Boost technique combined with low dosage contrast agents for CT pulmonary angiography(CTPA).Methods A total of 68 patients who would undergo CTPA examination due to suspected pulmonary embolism(PE)were prospectively enrolled and randomly divided into study group(n=34)and control group(n=34)using block randomization method.After injecting 25 ml contrast agents at a flow rate of 2.5 ml/s in study group or 50 ml contrast agents at a flow rate of 3.5 ml/s in control group,CTPA scanning were performed with identical parameters.For images in study group,hybrid iterative reconstruction was performed,followed by flexible subtraction CE-Boost post-processing to obtain CE-Boost CTPA.For images in control group,conventional CTPA was obtained with hybrid iterative reconstruction.Subjective and objective evaluations of image quality were compared between groups.Taken the final clinical diagnosis as standard,the accuracy rate of diagnosing PE were compared between groups.Results There were 7 cases of pulmonary artery main trunk PE and 15 cases of pulmonary lobe-level PE in study group,while in control group there were 8 cases and 17 cases.No statistical difference of subjective scores of CTPA was found between groups(P＞0.05).CT values of the main pulmonary artery,bilateral pulmonary artery trunks and lower lobes of both lungs,signal-to-noise ratio or contrast-to-noise ratio in CTPA were not significantly different between groups(all P＞0.05),while no significant difference of the accuracy rate of CTPA for diagnosing PE of pulmonary artery main trunk(100％[7/7]vs.100％[8/8])nor pulmonary lobe-level PE(86.67％[13/15]vs.88.24％[15/17])was detected between groups(all P＞0.05).Conclusion Flexible subtraction CE-Boost technique combined with low dosage contrast agents for CTPA could reduce contrast agent dosage without affecting image quality.

In order to establish a method for the detection of serum antibodies to donkey-derived e-quine coronavirus(ECoV),recombinant ECoV N protein was expressed in E.coli system,purified by nickel column affinity chromatography and identified by Western blot.After optimizing the re-action conditions,the indirect ELISA(iELISA)detection method was established using the puri-fied recombinant protein as coating antigen and used to detect 143 clinical serum samples.The re-sults showed that the recombinant N protein,which has good reaction activity with serum antibod-y,was successfully expressed.The optimum conditions of the established iELISA method were as follows:the amount of antigen coated was 0.2 μg/well and overnight at 4 ℃,10％skimmed milk powder solution was sealed at 37℃ for 1.5 h,the dilution concentration of serum was 1∶200,and the enzyme-labeled secondary antibody diluted at 1∶10 000.The sensitivity test results showed that the positive serum could be diluted to 1∶6 400.The specificity test results showed that all an-tibodies to several donkey pathogens were negative.The repetitive test results showed that the in-tra-and inter-batch coefficients of variation were 2.90％-6.12％and 2.29％-7.88％respectively.The positive rate of clinical donkey serum was 57.3％.The iELISA established in this study pro-vides a technical support for epidemiological investigation and antibody surveillance.

Objective:To investigate the feasibility of ultra-low dose (ULD) CT pulmonary angiography (CTPA) combined with deep learning reconstruction (DLR) in the diagnosis of pulmonary embolism (PE).Methods:This cross-sectional study prospectively enrolled 100 patients with suspected PE who underwent CTPA examination in Zhongshan Hospital Fudan University, and Shanghai Geriatric Medical Center from April to July 2024, and were randomly divided into the routine dose (RD) group and ULD group according to block randomization. Effective dose (ED) were calculated. The noise index of RD group and ULD group was set to 10 and 20, respectively. Other scanning parameters and contrast agent injection protocol were the same. The CT images of RD group were reconstructed using hybrid iterative reconstruction (HIR), while ULD images were reconstructed with HIR and DLR (ULD-HIR subgroup and ULD-DLR subgroup). The image quality of the three groups of images was subjectively evaluated (overall image noise, pulmonary artery display) and objectively evaluated [signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) of the images] respectively. Finally, the diagnostic results of PE by the expert committee composed of three chief physicians were taken as the gold standard, and one physician with lower qualifications independently evaluated the diagnostic rate of PE in the three groups of images. Objective image quality parameters across the three groups were compared using ANOVA, with LSD post hoc test was used for multiple comparisons. Subjective scores among the three groups were analyzed using the Kruskal-Wallis H test, with Bonferroni corrected pairwise post hoc test was applied for multiple pairwise comparisons. Results:The ED in the RD group and ULD group were (2.7±0.5) mSv and (0.7±0.2) mSv, respectively, and the differences were statistically significant ( t=26.42, P<0.001). The overall differences in CT values of pulmonary arteries at all levels in the images of the RD group, the ULD-HIR subgroup, and the ULD-DLR subgroup were not statistically significant ( P>0.05).The RD group, ULD-HIR subgroup and ULD-DLR subgroup overall differences in SNR and CNR at all levels pulmonary arteries were statistically significant ( P<0.001), in which except for the differences in CNR and SNR values of the left pulmonary arterial trunk in the RD group and the ULD-HIR subgroup, and SNR values of basal segment pulmonary artery of the lower lobe of the left lung, which were not statistically significant ( P>0.05), the differences of the rest of the indexes in the pairwise comparisons between the groups were statistically significant ( P<0.05). The overall differences in the subjective scores of image pulmonary vascular display and image noise in the RD group, ULD-HIR subgroup and ULD-DLR subgroup were statistically significant ( P<0.001), except that the differences in the subjective scores of image pulmonary vascular display in the ULD-DLR subgroup were not statistically significant when compared with that of the RD group ( P>0.05) and that of the rest of the metrics in the between-groups two-by-two comparisons were all statistically significant ( P<0.05). The difference in diagnostic rates of PE in the pulmonary artery trunk, lobe and segmental levels in the images of the RD group, ULD-HIR subgroup and ULD-DLR subgroup was not statistically significant ( P>0.05). Conclusions:DLR can significantly reduce the radiation dose of CTPA examination. Even at ultra-low radiation dose, its image quality is still better than HIR reconstruction at conventional doses and preserve diagnostic accuracy of PE at the lobe level and segment level.

Objective To investigate the value of flexible subtraction CE-Boost technique combined with low dosage contrast agents for CT pulmonary angiography(CTPA).Methods A total of 68 patients who would undergo CTPA examination due to suspected pulmonary embolism(PE)were prospectively enrolled and randomly divided into study group(n=34)and control group(n=34)using block randomization method.After injecting 25 ml contrast agents at a flow rate of 2.5 ml/s in study group or 50 ml contrast agents at a flow rate of 3.5 ml/s in control group,CTPA scanning were performed with identical parameters.For images in study group,hybrid iterative reconstruction was performed,followed by flexible subtraction CE-Boost post-processing to obtain CE-Boost CTPA.For images in control group,conventional CTPA was obtained with hybrid iterative reconstruction.Subjective and objective evaluations of image quality were compared between groups.Taken the final clinical diagnosis as standard,the accuracy rate of diagnosing PE were compared between groups.Results There were 7 cases of pulmonary artery main trunk PE and 15 cases of pulmonary lobe-level PE in study group,while in control group there were 8 cases and 17 cases.No statistical difference of subjective scores of CTPA was found between groups(P＞0.05).CT values of the main pulmonary artery,bilateral pulmonary artery trunks and lower lobes of both lungs,signal-to-noise ratio or contrast-to-noise ratio in CTPA were not significantly different between groups(all P＞0.05),while no significant difference of the accuracy rate of CTPA for diagnosing PE of pulmonary artery main trunk(100％[7/7]vs.100％[8/8])nor pulmonary lobe-level PE(86.67％[13/15]vs.88.24％[15/17])was detected between groups(all P＞0.05).Conclusion Flexible subtraction CE-Boost technique combined with low dosage contrast agents for CTPA could reduce contrast agent dosage without affecting image quality.

Objective : To study diagnostic value of ultrasonic cardiography (UCG) for right heart occupying lesions (RHOL).Methods :A total of 48 RHOL patients ,who were diagnosed in our hospital from Jan 2014 to Jun 2017 , were selected .All patients received UCG and pathological examination to determine lesion location and type .With pathological examination as gold standard ,diagnostic coincidence rate of UCG for RHOL type was analyzed .Re‐sults :RHOL distribution :compared with superior&inferior vena cava ,there were significant rise in percentages of RHOL located at right atrium ,right ventricle and pulmonary artery (6.25% vs.31.25%, 29. 17%, 33. 33%) , P＜0.01 all.RHOL type :percentage of malignant occupation was significantly higher than those of thrombus and myxoma (54.17% vs.20. 83%, 25.00%) , P＜0. 01 both .With pathological examination as gold standard ,diag‐nostic coincidence rates of UCG for thrombus ,malignant occupation and myxoma were 80.00%, 92. 86% and 100% respectively ,there was no significant difference among them , P＝0. 220 .A total of 18 cases (37.50%) with peri‐cardial effusion were found by UCG ,including two cases (4. 16%) who were diagnosed as benign thrombotic lesion by pathological examination ,and the other 16 cases (33.33%) were caused by malignant RHOL invading right heart system ,which included two cases (4.16%) of essential RHOL and 14 cases (29. 17%) with malignant lesion heart metastasis from other sites .Conclusion :RHOL type mainly includes thrombus ,malignant occupation and myxoma , and malignant occupation possesses relatively high incidence rate ,and it usually comes from malignant tumor metas‐tasis from other sites .Accuracy of UCG is high in diagnosing RHOL ,which is worth extending .