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.

Objective To explore the imaging findings and diagnostic value of magnetic resonance imaging(MRI)on thoracolumbar burst fractures accompanied with Kummell's disease.Methods A retrospective analysis was conducted on 102 patients with suspected thoracolumbar burst fractures accompanied with Kummell's disease in Sichuan Province Orthopedic Hospital.All patients underwent MRI examination.The clinical surgical diagnosis was taken as the gold standard to study the diagnostic value of MRI on thoracolumbar burst fractures accompanied with Kummell's disease and the detection of ligament injuries at thoracolumbar fracture site,and the MRI findings of thoracolumbar burst fractures accompanied with Kummell's disease were analyzed.Results The surgical results reported that out of 102 cases,58 cases were positive for thoracolumbar burst fractures accompanied with Kummell's disease and 44 cases were negative,while MRI diagnosis revealed that there were 60 positive cases and 42 negative cases,including 5 cases of missed diagnoses and 7 cases of misdiagnoses.MRI had a diagnostic sensitivity,specificity,accuracy,positive predictive value,negative predictive value and Kappa value of 91.37%,84.09%,88.23%,88.33%,88.09%and 0.758,respectively,indicating a high consistency with surgical results.The detection rates of anterior longitudinal ligament,posterior longitudinal ligament,supraspinous ligament and interspinous ligament injuries through MRI were close to surgical results(P>0.05).MRI examination showed various degrees of vertebral compression and flattening in 30 cases out of 58 cases of thoracolumbar burst fractures accompanied with Kummell's disease,and wedge-shaped changes in 25 cases.On MRI plain scan,normal bone marrow signals were still found in vertebral body in 28 cases.There were 54 cases with patchy T2WI hypointensity and lipid-suppression hypointensity in vertebral body,4 cases with thin epidural hematoma at corresponding level of vertebral body,33 cases with hypointensity on T2WI of the injured vertebral body,and 17 cases with hyperintensity on T2WI of the injured vertebral body,with the damaged ligament area being black banded structure fracture and hyperintensity on T2WI.Conclusion MRI has high diagnostic value on thoracolumbar burst fractures accompanied with Kummell's disease,and it can clearly display the signal characteristics of the diseased vertebra.

Distant metastasis is one of the main obstacles to cancer treatment.Overexpression of S1PR1 in malignant tumors enhances cell invasion and migration activity,mediates EMT and induces lymphangiogenesis and angiogenesis via activation of its downstream signaling pathways,eventually results in the occurrence of tumor metastasis.S1PR1 is also closely related to generation of acquired radiotherapy resistance.This article discusses the roles of S1PR1 in tumor metastasis and radiotherapy resistance.