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 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 the protective effects of ligustrazine-scutellarein twin drug ST-11 on rat adrenal medullary pheochromocytoma PC12 cell injury induced by oxygen-glucose deprivation/reperfusion （OGD/R） and its mechanism. METHODS PC12 cells were divided into blank group， model group， nimodipine group （positive control， 5 μmol/L） and different concentration groups of ST-11 （5， 10， 20 μmol/L）. After 24 hours of pre-administration intervention， all the other groups except the blank group were cultured in glucose-free DMEM culture medium containing 10 mmol/L Na2S2O4 for 4 hours with glucose deficiency and hypoxia. After 4 hours of glucose and oxygen re-introduction， the survival rate of cells in each group， the contents of lactate dehydrogenase （LDH）， catalase （CAT）， glutathione （GSH）， malondialdehyde （MDA） and superoxide dismutase （SOD） in cell supernatant， apoptosis rate， the levels of reactive oxygen species （ROS） and mitochondrial membrane potential （MMP）， the protein expressions of B-cell lymphoma 2 related X protein （Bax）， B-cell lymphoma 2 （Bcl-2） and caspase-3 were all detected in each group. RESULTS Compared with blank group， the cell survival rate， the contents of CAT， GSH and SOD in cell supernatant， MMP level， relative expression of Bcl-2 and Bcl-2/Bax ratio in model group decreased significantly （P＜0.05）， while the contents of LDH and MDA， ROS level， apoptosis rate， relative expressions of Bax and caspase-3 were significantly increased （P＜0.05）. Compared with model group， above indexes of ST-11 groups （except for the protein expression of caspase-3 in 5 μmol/L ST-11 group） were reversed signifi-cantly （P＜0.05）. CONCLUSIONS ST-11 has a certain protec-tive effect on OGD/R-injured PC12 cells， and its effects may be related to reduction of oxidative stress and inhibition of cell apoptosis.

BACKGROUND: It has been found that vascular endothelial growth factor can induce the differentiation of bone marrow mesenchymal stem cells into endothelial cells, but can the vascular endothelial growth factor gene promote the differentiation of bone marrow mesenchymal stem cells into vascular endothelial cells in the damaged organ under the hypoxic environment? OBJECTIVE: To observe whether human bone marrow mesenchymal stem cells induced by vascular endothelial growth factor could differentiate into vascular endothelial cells under hypoxia. METHODS: The third passage of human bone marrow mesenchymal stem cells were cultured in vitro. Cells in the control group were cultured with conventional culture medium, while those in experimental group were cultured with adenovirus vector containing vascular endothelial growth factor in 5% O2. After 2 weeks of culture, morphological observation and surface-related molecular detection were performed. The levels of vascular endothelial growth factor and endothelial nitric oxide synthase were detected by ELISA. The expression of endothelin and prostacyclin was detected by RT-PCR and western blot assay. RESULTS AND CONCLUSION: (1) The number of cells in the control group was more than that in the experimental group. The cells in the control group were crowded and arranged irregularly, showing a fiber-like growth, while those in the experimental group were mostly triangular or polygonal, exhibiting a colony-like growth. (2) CD31 was negative in the control group, while CD105 was positive and the positive rate was 99.7%, indicating that the cells still showed the phenotype of bone marrow mesenchymal stem cells. The positive rate ofCD31 was significantly increased to 30.33% in the experimental group and the positive rate of CD105 expression was decreased to 58.11%, indicating a typical phenotype of endothelial cells. (3) Compared with the control group, the expression of endothelin, vascular endothelial growth factor and endothelial nitric oxide synthase increased significantly in the experimental group (P < 0.05), and the expression of prostacyclin decreased significantly (P < 0.05). All these findings indicate that vascular endothelial growth factor can promote the differentiation of human bone marrow mesenchymal stem cells into vascular endothelial cells under hypoxia.

Objective To study the presence of CD4+CD25+regulatory T cells and hepatitis B virus(HBV)specific cytotoxie T lymphocyte(CTL)in peripheral blood and liver tissues of patients with chronic hepititis B(CHB)and its clincial significance.Methods One hundred and fifty-seven HBV-infected patients,including 20 cases of acute hepatitis B,115 cases of chronic hepatitis B,and 22cases of HBV-related liver cirrhosis,and 20 healthy controls were enrolled in this study.Peripheral blood was collected and liver tissues were obtained from some of the enrolled subjects.The CD4+CD25+regulatory T cells and HBV specific CTL were analyzed using flow cytometry and cytokine flow cytometry(CFC).The comparison between groups was done by t test.Results The percentages of CD4+CD25+ regulatory T cells in the peripheral blood of patients with acute hepatitis B and CHB of mild,moderate and severe degree were(2.87±0.94)%,(3.53±1.56)%,(4.59±2.98)%and(3.65±1.73)%,respectively,which were higher than that of controls(2.36±0.60)%(t=2.04,5.97,3.30 and 3.17,respectively,P<0.01).The percentages of HBV specific CTL in the peripheral blood of patients with mild,moderate and severe degree of CHB and HBV-related liver cirrhosis were (0.189±0.152)%,(0.103±0.110)%,(0.118±0.120)%and(0.098±0.101)%,respectively,which were significantly lower than that of acute hepatitis patients [(0.815±0.360)%](t=10.09,11.87,9.17 and 8.96,respectively,P<0.01).CD4+CD25+ regulatory T cells and HBV specific CTL in liver tissues were both higher than those in the peripheral blood.Conclusion CD4+CD25+regulatory T cells may play an important role in anti-HBV immune response through inhibiting CD8+T eell function.