双能量CT诊断颈椎间盘退变及突出症的价值

The value of dual-energy CT in cervical intervertebral disc degeneration and herniation

目的:探讨应用双能量CT(dual-energy CT,DECT)电子云密度/等效原子系数(Rho/Z)诊断颈椎间盘退变(cervical disc degeneration,CDD)及突出症的可行性。方法:回顾性分析50例颈痛不适患者颈椎MRI及DECT成像资料,根据Pfirrmann分级标准对颈椎间盘变性进行分级,并在彩色编码重建图像上测量椎间盘髓核的Rho值。采用单因素方差分析比较不同分级椎间盘以及不同节段椎间盘髓核的Rho值差异,并采用Spearman相关分析Rho值与颈椎间盘退变分级的相关性。以MRI作为参考标准,分析常规灰度CT图像及双能量彩色编码重建图像对颈椎间盘突出症的敏感性、特异性、阳性预测值、阴性预测值和准确性。结果:颈椎间盘髓核的Rho值随Pfirrmann分级增加而升高,随节段位置的下降而下降,差异均有统计学意义(P<0.001)。颈椎间盘髓核的Rho值与Pfirrmann分级呈中度正相关(r=0.584,P<0.05)。双能量彩色编码重建图像较常规灰度CT图像诊断颈椎间盘突出症具有更高的敏感性(86.7%vs 74.3%)、特异性(90.2%vs 79.3%)、阳性预测值(96.7%vs 92.3%)、阴性预测值(66.9%vs 48.0%)和准确性(87.5%vs 75.5%)。结论:DECT诊断颈椎间盘退变及突出症是可行的,彩色编码重建图像可显著提高颈椎间盘突出症的诊断准确率;颈椎间盘髓核的Rho值可反映椎间盘退变程度。

Objective:To assess the feasible of Rho/Z value derived from dual-energy computed tomography(DECT)in cervical disc degeneration(CDD)and herniation.Methods:MRI and DECT imaging data of 50 patients with neck back pain were included.All discs were classified on the basis of Pfirrmann grading system.Rho value of nucleus pulposus were measured and the variances in different grades and different disc level were analyzed with one-way ANOVA test.Correlations between Rho value and grades were analyzed with Spearman correlation test.MRI as the reference standard,the sensitivity,specificity,PPV,NPV and accuracy of conventional grayscale CT images and dual-energy color-coded reconstructed images in the detection of cervical disc herniation were compared.Results:The Rho value of nucleus pulposus in cervical intervertebral disc increased with the increase of Pfirrmann grade and decreased with the decrease of segmental position,and the difference was statistically significant(P<0.001).There was a moderate positive correlation between Rho value of nucleus pulposus and Pfirrmann grades(r=0.584,P<0.05).Dual-energy color-coded reconstructed images had higher overall sensitivity(86.7%vs 74.3%),specificity(90.2%vs 79.3%),PPV(96.7%vs 92.3%),NPV(66.9%vs 48.0%)and accuracy(87.5%vs 75.5%)in detecting cervical disc herniation compared conventional grayscale CT images.Conclusions:The color-coded reconstruction image of DECT can significantly improve the diagnostic accuracy of cervical disc herniation,and the Rho value of nucleus pulposus is associated with the degree of intervertebral disc degeneration.