Application Of Diffusion Tensor Imaging Quantitative Index In Cervical Spondylotic Myelopathy

Objective: By analyzing and comparing the changes of diffusion tensor imaging(DTI)parameters in patients with cervical spondylotic myelopathy(CSM)with chronic spinal cord injury before operation,to explore the characteristics of spinal cord injury in CSM patients before operation,and to analyze the correlation between DTI parameters and clinical function in CSM patients combined with clinical scale before and after decompression.Methods:1.Thirty-five healthy volunteers(30-60 years old)were recruited.They were divided into groups A(30-40),B(41-50)and C(51-60)according to age.DTI parameters(ADC and FA values)of the white matter(bilateral anterior,lateral and posterior cords)of the spinal cord at C1-C7 level were measured,and the relationship between DTI parameters and age was analyzed.2.Thirty-five patients with cervical spondylotic myelopathy(CSM)diagnosed by imaging and clinical methods were collected from the First Affiliated Hospital of Nanchang University.Thirty-five healthy volunteers matched in sex and age were recruited as control group(HC).Both groups received DTI scan of cervical spinal cord.In CSM group,ADC and FA values(mean white matter,posterior cord)of the cervical spinal cord maximum compression plane and C1/2 segment(level of intervertebral disc)were measured.The ADC and FA values(mean white matter,posterior cord)of C1-C7 cervical white matter were measured in HC group.The JOA scores of CSM patients before and 6 months after operation were evaluated and the improvement rate was calculated.The JOA scores of CSM patients before operation were divided into severe injury(< 8),moderate injury(< 9-12),and mild injury(>13-16)into three groups.The improvement rate after operation was divided into two groups according to < 50% and > 50% [1].The ADC and FA values of cervical spinal cord between CSM and HC groups were analyzed by IBM SPSS 22.0software.The DTI parameters(ADC and FA values)of cervical spinal cord were correlated with the JOA score,NDI score and the clinical function scale(JOA score,NDI score)of CSM patients before and after operation.The characteristics of ADC and FA values in cervical spondylotic myelopathy patients with different degrees were analyzed and the working characteristics of the subjects were drawn.The diagnostic value of DTI quantitative indicators measured by ROC in CSM patients and the predictive value of evaluation on the recovery of spinal cord function after CSM patients.Results:(1)The ADC value(mean white matter,posterior cord)of cervical intervertebral disc level in healthy control group increased from C1/2-C6/7 level,while FA value showed a downward trend;the ADC value of C1/2 and C2/3 cervical intervertebral disc level decreased compared with C3/4-C6/7 level,while FA value increased;the ADC value of C3/4 cervical intervertebral disc level decreased compared with C5/6-C6/7 level,while the FA value increased compared with C4/5-C6/7 level.The ADC values of 5/6 cervical intervertebral disc level were lower than those of C6/7 level,but FA values were increased(P < 0.05).The ADC values of C5/6 level of cervical intervertebral disc(mean white matter,posterior cord)were correlated with age,FA values and age were not correlated.(2)The ADC values at the most significant levels(white matter mean,posterior cord)and C1/2 in CSM group were higher than those in HC group(p < 0.05),while FA values were lower(p< 0.05).(3)In CSM group,the FA value of cervical white matter(mean)was positively correlated with clinical JOA score,motor function JOA score and lower limb motor function JOA score,and the FA value of posterior cord was positively correlated with JOA score,sensory function JOA score and lower limb sensory function JOA score(p < 0.05).In CSM group,C1/2 white matter FA was positively correlated with JOA score of lower limb sensory function and JOA score of lower limb motor function.(4)The sensitivity and specificity of DTI parameters ADC and FA in the diagnosis of CSM were 87.9%,100%,72.7% and 73.9%,respectively;(4)As clinical symptoms worsened(i.e.,JOA score decreased),the most obvious level of pressure ADC(white matter average)showed a downward trend,while FA(white matter average,posterior cord)showed a downward trend.(5)When the FA value of DTI parameter was less than 0.505,the sensitivity and specificity of predicting spinal cord dysfunction in CSM group were 82.3% and 100%,respectively.Conclusions:(1)There are significant differences in white matter of cervical spinal cord among healthy volunteers of different ages and segments.The influence of age and segments should be fully considered when using DTI parameters to analyze CSM patients.(2)DTI parameters of cervical spinal cord(ADC,FA values)can assess the severity of spinal cord injury.Spinal cord injury is not limited to the compressed segment.FA values of cervical spinal cord posterior cord can objectively reflect the degree of spinal cord sensory impairment in CSM patients to a certain extent.(3)Preoperative detection of FA and ADC values of cervical spinal cord has certain reference value for predicting and evaluating the clinical function recovery after CSM.