The Value Of Multimodal 3.0T MRI For The Entrapment Of The Proximal Sciatic Nerve

Part Ⅰ:The value of multimodal 3.0T MRI in the observation of normal proximal sciatic nerveObjective:To compare and analyze the multiple echo converged gradient echo(MERGE),iterative decomposition of water and fat with echo asymmetric and lead squares estimation(Ideal),and diffusion tensor Imaging(DTI)and nerve fiber bundle tracing imaging were used to observe the imaging value of normal proximal sciatic nerve.Methods:21 healthy volunteers were recruited to complete the multimodal sequence of bilateral sciatic nerve including MERGE,Ideal,DTI and fiber tracking imaging with 3.0T MR.Two neuroimaging physicians completed the volume imaging sequence including MERGE and Ideal sequence to analyze the display value of sacral 1 nerve and proximal sciatic nerve.FA values were measured at the level of bilateral sacral 1 nerve roots(a level),the level of the inferior margin of the inferior margin of the sciatic nerve(c level)and the midpoint of the two levels(b level,the starting point of the general branch of the sciatic nerve).The left and right values were compared and analyzed.To complete the fiber tracing imaging observation of bilateral proximal sciatic nerve.Results:42 sciatic nerves of 21 cases were imaged.The comparison of the display scores of MERGE and Ideal sequences on sacral 1 nerve was 3.000±0.000 and 2.762±0.431,respectively,P<0.05.The scores of the proximal value of bone nerve were 2.810±0.397 and 2.357±0.759,respectively,P<0.05.The analysis of the excellent and good rate of sacral 1 proximal sciatic nerve was 100%and 83.3%in MERGE and Ideal sequences,respectively,P<0.05.The FA values of left and right sciatic nerve layers were:a level(0.326±0.007,0.325±0.007,P>0.05),b level(0.400±0.007,0.401±0.008,P>0.05),c level(0.525±0.006,0.526±0.007,P>0.05),the FA values of left and right sciatic nerve ab level,ac level and be level were all<0.05.The tracing image of normal proximal sciatic nerve fiber showed that the shape of nerve fiber was natural and continuous,the distribution of fiber bundle was uniform,and the edge was clear.Conclusion:Both MERGE and Ideal sequences can clearly display the normal proximal sciatic nerve,and MERGE sequence is superior to Ideal sequence in displaying the proximal sciatic nerve.FA values of different levels of sciatic nerve have significant differences,which is of great significance to the analysis of nerve function of different levels.Part Ⅱ:The value of multimodal 3.0T MRI for the entrapment of the proximal sciatic nerveObjective:To evaluate the diagnostic value of multimode 3.0T magnetic resonance imaging(MERGE,Ideal,DTI)in the compression of proximal sciatic nerve.Methods:According to the inclusion and exclusion criteria,the patients with unilateral proximal sciatic nerve compression were collected and completed routine MRI scan,MERGE,Ideal and DTI scan.The difference of FA value between the affected side and the healthy side of the same level in the sciatic nerve compression group and the average value of FA value in the corresponding level in the healthy control group were compared;the difference of FA value between the a,b and c levels of the affected side and the corresponding level in the healthy side were compared.To analyze the relationship between FA value and VAS score of patients in sciatic nerve compression group.Two neuroimaging doctors read the film by blind method,and compared the diagnostic value of conventional MRI and multimodal MRI in the compression of the proximal sciatic nerve,and drew ROC curve by medcalc,and compared the area under the curve.Results:21 patients were included 42 sides of sciatic nerve imaging.The FA values of the affected side and the healthy side were 0.270±0.032 and 0.399±0.011,respectively,P<0.05 in the sciatic nerve compression group and 0.270±0.032 and 0.401±0.007 in the healthy control group,There was no significant difference in FA value between the affected side and the healthy side(0.324±0.007,0.326±0.005,P>0.05),but there was no significant difference in FA value between the two sides(0.270±0.032,0.399±0.011,P<0.05),and there was significant difference in FA value between the two sides(0.400±0.012,0.525±0.007,P<0.05).The correlation coefficients between the FA value at the side of the sciatic nerve compression,the FA value at the same level of the healthy side and the FA value at the side of the sciatic nerve compression were-0.418 and 0.436,respectively,P>0.05.The sensitivity,specificity and accuracy of conventional MRI sequence were 61.90%,71.43%and 66.67%respectively.The sensitivity,specificity and accuracy of multimodal MRI in the diagnosis of proximal sciatic nerve card were 80.95%,90.48%and 85.71%,respectively.The area under ROC curve of conventional MRI sequence and multimodal MRI diagnosis was 0.667 and 0.857,respectively(P<0.05).Conclusion:compared with conventional MRI,3.0T MR multimodal imaging has a better display effect and higher diagnostic value for the compression of the proximal sciatic nerve.DTI and ft of functional imaging are helpful to assist diagnosis and improve accuracy.