DTI在腰椎间盘突出引起腰骶神经根压迫症中的应用价值

Value of DTI in the evaluation of lumbosacral nerve entrapment in disc herniation

目的:探讨腰骶神经根扩散张量成像(DTI)及纤维示踪成像(FT)的可行性,同时评定健康志愿者及腰椎间盘突出引起单侧坐骨神经痛患者的腰骶神经根DTI参数不同层面数值的连续性变化。方法:将20例腰椎间盘突出引起单侧坐骨神经痛的患者及20例与患者年龄相仿的健康志愿者同时纳入研究。所有检查均在Siemens 3.0T MR上进行,采用3DT1-VIBE及DTI融合图像,分别在神经根(L5和S1)的三个不同层面测量左右两侧神经根的各向异性分数(FA)值和ADC值,同时进行L4、L5、S1神经根FT。结果:20例健康志愿者L5和S1神经根左、右两侧FA值分别为0.319±0.019和0.320±0.019,ADC值分别为1.427±0.171和1.416±0.185,左右两侧差异无统计学意义(P>0.05);不同层面神经根两两之间的FA及ADC值差异无统计学意义(P>0.05)。20例患者的患侧神经根FA值低于健侧,分别为0.285±0.026和0.319±0.019,差异有统计学意义(P<0.05);患侧神经根近端至远端FA值逐层递减(P<0.05),ADC值逐层递增(P<0.05);健侧不同层面FA值无明显差异(P>0.05)。结论:DTI结合常规MRI对定量评价病变神经根及定位诊断腰骶神经根卡压有一定的应用价值。

Objective：To study the feasibility of diffusion tensor imaging（DTI）and fiber tracking（FT）in the evaluation of lumbar-sacral nerve root,and to assess the potential changes of DTI parameters in different levels of the lumbar nerve roots in healthy volunteers and patients suffering with unilateral sciatica caused by disc herniation.Methods：20patients with unilateral sciatica related to disc herniation and 20 healthy volunteers with similar age were enrolled in this study.All of the subjects were studied with a 3.0T MR scanner,3D T1-VIBE and DTI fusing images were used.The FA and ADC values on three different levels of bilateral L5 and S1nerve roots were measured,tractography of L4-S1 nerve root fiber was performed simultaneously.Results：There was no significant difference in FA or ADC between left and right nerve roots at the same level of L5 and S1（left FA：0.319±0.019,right FA：0.320±0.019;left ADC：1.427±0.171,right ADC：1.416±0.185;P〉0.05）in healthy volunteers.No significant difference was existed on FA and ADC values at different levels of nerve root（P〉0.05）.Of the 20 patients with sciatica,the FA values were significantly lower at the affected side compared with the healthy side,which was 0.285±0.026,0.319±0.019respectively（P〈0.05）.The FA values of the nerve roods of affected side decreased and declined gradually from proximal to distal（P〈0.05）;while the ADC values was on the opposite trend,which accented gradually（P〈0.05）.FA values in healthy side showed no difference at different levels（P〈0.05）.Conclusion：DTI in combination with conventional MRI show significant potential in the quantitative evaluation as well as providing localization of nerve root compression.