Objective To compare the performances of 3D MERGE sequence and 3D SPACE STIR sequence in detecting lumbar disc herniation(LDH).Methods The clinical data and MRI data of 135 LDH patients admitted between January 2020 and November 2022 were analyzed retrospectively.All patients were examined using conventional MRI,3D MERGE sequence and 3D SPACE STIR sequence.The consistency of 3D MERGE sequence and 3D SPACE STIR sequence in measuring the diameter of nerve root was analyzed,and the image quality parameters[signal-to-noise ratio(SNR),contrast-to-noise ratio(CNR)]and image definition score of the two sequences were evaluated.Results There were no statistically significant differences in L3-S1 nerve root diameters measured by 3D MERGE sequence and 3D SPACE STIR sequence(P＞0.05),and the diameters of L3,L4,L5 and S1 measured by the two sequences showed high correlations(r=0.957,0.986,0.975,0.972,P＜0.05).Compared with 3D SPACE STIR sequence,3D MERGE sequence had higher SNR and CNR,scored better on image definition,and displayed nerve root more clearly(P＜0.05).Conclusion 3D MERGE sequence and 3D SPACE STIR sequence have high consistency in the measurement of LDH nerve root diameter.3D MERGE sequence can display the anatomical morphology of nerve root more clearly as compared with 3D SPACE STIR sequence,and the former one has higher image quality.

This study was performed to investigate the effects of mitogen-activated protein kinase(MAPK)pathway inhibitors on the expression of PD-L1 in dendritic cells and the T lymphocyte immune response in gram negative bacterial sepsis.The immunosuppression model of bacterial sepsis was established by treating the dendritic cells with bacterial endotoxin.The MAPK pathways inhibitors were applied to block pathways of dendritic cells,and then the PD-L1 expression on dendritic cells were detected by flow cytometry and Western blotting.Furthermore,the levels of T lymphocyte proliferation response and cytotoxic T cell response in mixed lymphocyte co-culture experiments were detected by cell proliferation assay kit and enzyme-linked immunospot assay kit,respectively.Data showed that the PD-L1 expression of dendritic cells were significantly up-regulated in the model group compared with the control group,while the levels of T lymphocyte proliferation response and cytotoxic T cell response in the model group were significantly reduced(P<0.05).Then compared with the model group,the PD-L1 expression of dendritic cells were significantly down-regulated in the SB203580/model group(P<0.05),meanwhile the levels of T lymphocyte proliferation response and cytotoxic T cell response were both significantly increased in SB203580/model group and αPD-L1/model group(P<0.05).In conclusion,the p38 signaling pathway could regulate PD-L1 expression of dendritic cells in bacterial sepsis.The application of p38 pathway inhibitors could partially reduce the PD-L1 expression of dendritic cells and reverse T lymphocyte immunosuppression in bacterial sepsis.