正常颈髓扩散张量成像扩散参数的影响因素和相关性研究

Factors and Association studies of Diffusion Coefficients in Diffusion Tensor Imaging of Normal Cervical Spinal Cord

目的探讨在正常成人颈段脊髓磁共振扩散张量成像(DTI)中脊髓节段、轴索及年龄因素对其扩散系数(ADC)值和各向异性分数(FA)值的影响。方法 36例健康志愿者按年龄分成3组接受常规颈椎3.0T磁共振成像(MRI)及颈髓DTI检查;根据颈椎体解剖定位,颈髓分为上段(C1/2-C2/3)、中段(C3/4-C4/5)及下段(C5/6-C6/7),各节段应用感兴趣区法测量脊髓中央灰质和白质(前索、侧索、后索)的ADC和FA值。结果正常成人颈髓灰、白质不同节段之间ADC和FA值均存在统计学差异(P<0.05),颈髓白质不同轴索之间ADC和FA值存在统计学差异(P<0.05),不同年龄组之间的ADC和FA值均存在统计学差异(P<0.05)。颈髓白质前索上段ADC与年龄不具有相关性,前索下段的ADC值与年龄正相关,其余颈髓白质及中央灰质的ADC和FA值均与年龄负性相关。结论正常颈髓的扩散能力和扩散各向异性受到年龄、节段和轴索因素的影响,对颈髓疾病的DTI研究应综合考虑上述因素。

Objective To investigate the effect of spinal segments, axons and age on apparent diffusion coefficient（ADC） and fractional anisotropy（FA） in normal adult cervical spinal cord magnetic resonance diffusion tensor imaging（DTI）. Methods A total of 36 healthy volunteers were enrolled and divided into 3 groups based on age. All subjects were received 3.0 T magnetic resonance imaging（MRI） for cervical vertebra and DTI for cervical spinal cord. According to intervertebral location, cervical spinal cord was defined as superior（C1/2-C2/3）, middle（C3/4-C4/5） and inferior segment（C5/6-C6/7）. The region of interest（ROI） method was used to detect ADC and FA values of white matter（WM） and gray matter（GM） in cervical spinal cord. Results The values of ADC and FA were significantly different in different segments of WM and GM in healthy cervical spinal cord（P〈0.05）. The values of ADC and FA were significantly different in different axons of WM（P〈0.05）. The values of ADC and FA were significantly different between different age groups（P〈0.05）. The value of ADC in the superior segment of WM front axon was not correlated with age. The value of ADC in the inferior segment of WM front axon was positive correlated with age, and the values of ADC and FA in the rest of regions were negative correlated with age. Conclusions The diffusion and anisotropy in healthy cervical spinal cord are influenced by age, segments and axons. The DTI study of cervical spinal cord disease should be considered comprehensively.