The Value Of DKI And DTI For Nerve Root In Cervical Disc Herniation With 3.0T Magnetic Resonance

Object:To investigate the value of Diffusion Tensor Imaging(DTI)and Diffusion Kurtosis Imaging(DKI)in the assessment of nerve root caused by cervical disc herniation with 3.0T MR.Methods:32 patients with unilateral and single segment cervical disc herniation(CHD group)and 20 healthy volunteers(HC group)were enrolled.Routine MRI,coronary IDEAL,transverse DTI and DKI were performed with 3.0T MR.The DTI parameters including fractional anisotropy(FA),apparent diffusion coefficient(ADC)and the DKI parameters including mean kurtosis(MK),axial kurtosis(AK),and radial kurtosis(RK)were measured in the proximal and distal part of the nerve roots.The differences of the parameters between the involved nerve roots and the normal nerve roots were compared.The diagnostic value of each parameter for nerve root injury were evaluated with Receiver operator characteristic curve(ROC).The correlation between the changes of parameters of DTI and DKI and the visual analogue score(VAS)of pain or the disease duration were analyzed.Results:(1)For HC group,there was no statistical difference of DTI and DKI parameters between the left and right nerve root at the same cervical level,or between the proximal part and distal part at the same nerve root(P>0.05).(2)In CDH group,compared with the unaffected side,the FA,MK,AK and RK values of the proximal part and distal part nerve roots of the affected side were lower,the ADC values were higher(P<0.05).And RK values were the most significantly decreased in both the proximal and the distal(proximal:7.88%,distal:12.58%).In affected side,FA,MK,and RK in the distal part of the nerve root were lower than those in the proximal part(P<0.05).The average values of FA,MK,AK and RK of the nerve roots in CDH group were lower than those in HC group,and the average ADC value was higher than that in HC group(P<0.05).(3)The value of RK in the distal part of nerve root was the most effective for nerve root injury with ROC curve analysis.The area under the ROC curve(AUC)was 0.894,the sensitivity was 78.12%,and the specificity was 96.87%.(4)The difference of FA,MK and RK values between the unaffected side and the affected side was positively correlated with VAS score in CDH group(FA:r=0.380,MK:r=0.465,RK:r=0.478,P<0.05,respectively).The difference of MK and RK between the unaffected side and the affected side were negatively correlated with disease duration in CDH group(MK:r=-0.449,RK:r=-0.650,P<0.05,respectively).Conclusion:3.0T MR DKI technology can be used to evaluate human C5?C8cervical nerve root.The microscopic changes of nerve roots injury in patients with CDH can be evaluated both by DTI and DKI,which is expected to provide a new quantitative reference for early clinical assessment of nerve root injury.Among all metrics,the value of RK is a more diagnostic observation index.To some extent,the changes of FA,MK and RK reflect the severity of nerve root injury in CDH patients;the changes of MK and RK may be used as imaging markers to evaluate the course of CDH.