The Application Of DTI In Preoperative Accurate Localization And Predicting Prognosis Of Lumbosacral Plexus Nerve Roots Injury

Part I:Study on the discrimination of nerve roots injury caused by lumbar intraspinal stenosis and lumbar foramen stenosis by diffusion tensor imagingPurpose:To explore the value of DTI in the discrimination of nerve roots injury caused by lumbar intraspinal stenosis and foraminal stenosis.Materials and methods:60 patients with intraspinal stenosis,20 patients with foraminal stenosis and 20 healthy volunteers were prospectively recruited between December 2017 and September 2019 who met the following criterias were collected:(1)no spinal internal fixation history;(2)unilateral sciatica;(3)patients were surgically confirmed as L4 or L5,a single segment,nerve roots injury;(4)healthy volunteers:no lower back pain or sciatica.Patients and volunteers were underwent a preoperative MRI exam including Tl/2WI-sag,T2WI-tra,3D-T2WI-FFE and DTI sequences.Firstly,Philips workstation post-processing software was used to perform motion correction on DTI,and then 3D-T2WI-FFE sequence was used as the anatomical structure positioning image.Secondly,ROIs were delineated by outline method at 3 anatomical levels of bilateral L4 and L5 nerve roots:(near)the intraspinal region(the nerve roots from the dural sac to DRG),(middle)the foraminal region(DRG),and(far)the outer foraminal region(the posterior DRG).Thirdly,in the volunteer group,the Independent sample t test was used to compare whether there were statistical differences in FA values between the right and left sides,differences in FA values between L4 and L5 nerve roots and 3 anatomical levels.In the intraspinal and foraminal stenosis patients,Non-parameter Wilcoxon test was used to compare whether there were statistical differences in FA values between affected roots and unaffected roots.Spearson correlation method was used to evaluate the correlation between FA values and JOA scores in each group,and line graphs were used to show the variation trends of FA values in three anatomical levels in each group.And receiver operating characteristic(ROC)curve was used to evaluate the diagnostic value of DTI for intraspinal stenosis and foraminal stenosis.Results:in the volunteer group,FA values of the two sides of L4 or L5 nerve roots and at different levels showed no statistical difference(P>0.05).In intraspinal and foramina stenosis patients,FA values between affected roots and unaffected roots,anatomical levels showedstatistically significant differences(P<0.001).Intraspinal stenosis patients FA values were moderately correlated with JOA scores(r=0.570),and foraminal stenosis patients FA values were obviously correlated with JOA scores(r=0.886).The line graphs showed that FA values in each group have different trends at the three anatomic levels.ROC curve showed FA values<0.285 at the intraspinal level,the sensitivity and specificity of diagnosing intraspinal stenosis were 93.3%and 80.0%,and when FA values<0.325 at the foraminal level,the sensitivity and specificity of diagnosing foraminal stenosis were 80%and 90%.DTT showed that the affacted nerve roots in the intraspinal area of group A had changes such as displacement,thinning,compression and interrupt.And the affacted nerve roots in the foraminal area of group B had changes such as displacement,thinning,compression and interrupt.Then the bilateral nerve roots of the healthy volunteers were clear and integrity.Conclusions:DTI is valuable for the preoperative discrimination of nerve roots injury caused by lumbar intraspinal stenosis and foraminal stenosis.Part II:Study on the value of diffusion tensor imaging in predicting the prognosis after lumbosacral plexus nerve root injuryPurpose:To investigate the value of DTI in predicting the prognosis after lumbosacral plexus nerve root injury.Materials and methods:65 patients were prospectively recruited between December 2017 and March 2019 who met the following criterias were collected:(1)all patients underwent surgical treatment(2)followed up one year after surgery(3)the follow-up data were complete.Method:based on MacNab standard divided the patients into two groups(poor prognosis and great prognosis).Then comparison between the two groups of clinical,imaging and surgery data.Using Logistic regression method to analyze clinical,imaging and surgery data.Logistic regression models were established and the areas under the curve were calculated to analyze the predictive value of FA values.Hanley&Mcneil method was used to compare the differences of AUC between the regression models.Results:FA values,preoperative JO A scores,lesion locations and nerve root adhesion are surgery prognosis related factors.But age,gender,BMI,diabetes,course,lesion segment,operation method are not related factors.Prognostic model 1(preoperative JO A scores(X1),FA values(X2),adhesion(X3)and lesion locations(X4))AUC=0.914,model 2(preoperative JOA scores(X1),adhesion(X3)and lesion locations(X4))AUC=0.877,model 3(preoperative JOA score(X1),FA values(X2))AUC=0.779,model 4(FA value(X2))AUC=0.730,model 5(preoperative JOA score(X1))AUC=0.661.AUC of model 1 and 3,model 1 and 4,model 1 and 5,model 2 and 5 showed statistical differences(Z=2.229 P=0.0258,Z=2.856 P=0.0043,Z=3.188 P=0.0014,Z=3.090 P=0.0020).Conclusions:DTI has certain value in predicting prognosis after lumbosacral plexus nerve roots injury.