磁共振扩散张量成像对脊髓型颈椎病脊髓慢性损伤的评价

目的 评价磁共振扩散张量成像（DTI）对脊髓型颈椎病脊髓慢性损伤早期诊断的可行性。方法 采用单次激发平面回波成像（SE-EPI）序列对31例临床确诊的脊髓型颈椎病患者行颈髓常规MRI和DTI检查。测量病变处ADC值和FA值并按病变常规T2WI高信号阳性与阴性分组进行数据分析,计算常规MRI和DTI对颈髓病变检出的敏感度、特异度、阳性预测值（PPV）、阴性预测值（NPV）。结果所有脊髓型颈椎病患者均能完成DTI检查,后处理图像颈髓显示清晰,无明显图像变形及伪影。9例（29%）表现为颈髓病变T2WI高信号的患者均出现颈髓受压平面ADC值升高,FA值下降,平均ADC值为（1183.44±121.96）×10-6mm2/s,相应FA值为（432.56±59.97）×10-3,与正常值相比有统计学意义;22例（71%）颈髓病变T2WI高信号阴性患者中,7例（32%）病变处平均ADC值及FA较正常值无明显变化;15例（68%）颈髓受压平面ADC值升高,FA值下降,平均ADC值（1055.07±80.61）×10-6mm2/s,FA值为（501.87±41.09）×10-3,有统计学意义。检查方法的敏感度常规T2WI为29.0%,DTI为67.7%;特异度常规T2WI为71.0%,DTI为22.6%;PPV常规T2WI为27.3%,DTI为72.7%;NPV常规T2WI为75.9%,DTI为24.1%。结论 DTI较常规MRI更早期而准确地诊断脊髓型颈椎病颈髓慢性损伤,是一种显示脊髓型颈椎病颈髓病变和观察病变修复过程的有效手段。

Diffusion tensor MR imaging of cervical spinal cord: cervical spondylosis-related changes

Objective：To investigate the capacity of diffusion tensor MR imaging in the spondylosis-related changes of the cervical spinal cord. Materials and Methods：Thirty-one patients with cervical spondylosis were examined with routine MRI and DTI on SIEMENS Sonata 1.5T MR scanner using single shot echo planar imaging （SE-EPI） sequences. The images of cervical spinal cord were obtained. Apparent diffusion coefficient （ADC）,fractional anisotropy （FA） values were measured on a sagittal section according to whether there were high signal on T2-weighted images or not. Results：All 31 cervical spondylosis cases completed the examinations without obvious artifacts on the diffusion tensor images. The average ADC and FA values of high signal lesions on conventional T2-weighted images （9 cases） were 1183.44±121.96×10-6 mm2/s and 432.56±59.97×10-3 （P0.01,vs normal cervical spinal cord）. The average ADC and FA values of normal signal on T2-weighted images （15 of 22 cases） were 1055.07±80.61×10-6 mm2/s and 501.87±41.09×10-3 （P0.01,vs normal cervical spinal cord）,7 of 22 cases showed no signifi cant difference compared with normal cervical spinal cord. The sensitivity,specificity,positive predictive value,negative predictive value of T2-weighted images and DTI were 29.0% and 67.7%,71.0% and 22.6%,27.3% and 72.7%,75.9% and 24.1%,respectively. Conclusion：Diffusion tensor imaging is a reliable tool in demonstrating the early spondylosis-related changes of the cervical spinal cord compared with conventional T2-weighted images. It can provide useful information for chronic injury and regeneration of the cervical spinal cord.