扩散张量成像观察脊髓压迫症

Diffusion tensor imaging in observation of spinal cord compression

目的探讨采用3.0T MR研究亚急性及慢性脊髓压迫症(SCC)DTI及纤维束示踪(DTT)技术的可行性及临床应用价值。方法采用单次激励自旋回波平面回波成像对42例SCC患者(SCC组)及49名健康志愿者(正常对照组)行3.0T MR脊髓DTI。采用ROI法分别测量正常对照组的颈髓及下段胸髓的ADC和FA值及SCC病变部位受压脊髓的ADC及FA值。根据T2WI脊髓内有无高信号将SCC组分为SCC-HI和SCC-nHI亚组。统计学分析采用单因素方差分析。利用纤维束示踪软件重组脊髓纤维束。结果正常对照组脊髓各节段扩散定量值(ADC和FA值)差异无统计学意义;SCC-HI组与正常对照组扩散定量值间比较,病变脊髓ADC值增高(P<0.05),FA值减低(P<0.05);SCC-nHI与正常对照组间差异无统计学意义(P>0.05)。在DTT彩色编码图上,正常脊髓纤维束为头尾向的一束,显示了头尾侧的各向异性。SCC则表现为脊髓纤维束不同程度受压改变而无明显的破坏。结论 DTI和DTT是一种显示脊髓纤维束及其病变的有效方法,在临床中能为SCC患者的研究提供重要信息。

Objective To assess the feasibility and clinical value of DTI and diffusion tensor tractography（DTT） in evaluation of subacute and chronic spinal cord compression（SCC） at 3.0T MR.Methods Single-shot spin-echo echo-planar diffusion tensor sequences were performed on 42 patients with SCC（SCC group） and 49 healthy volunteers（control group）.The values of mean ADC and FA were measured in ROI placed at the cervical and lower thoracic cord on normal and then on the lesion site of SCCs.SCC patients were divided into 2 subgroups according to high intensity on T2WI,i.e.SCC-HI subgroup and SCC-nHI subgroup.One-way ANOVA was used to test the differences among the spinal segments and groups.The tracts were also visualized.Results There was no statistically significant differences of ADC and FA values among different spinal cord levels in normal subjects.All SCC-HI subgroup patients had increased ADC values（P0.05） and decreased FA values（P0.05） in the lesion level compared with the normal levels.There was no significant difference of diffusion indices between SCC-nHI subgroup and the control group（P0.05）.On the DTT maps,the normal spinal cord was depicted as a fiber tract showing color-encoded cephalocaudally.DTT in all SCC patients were compressed with different degree but without obvious damage.Conclusion DTI and DTT are promising methods for demonstrating the spinal cord tracts and abnormalities,providing information for the clinical study of SCC.