Lei Ting, Xie Hong-Ning, Zheng Ju, Feng Jie-Ling, Du Liu, Wang Nan
Department of Ultrasonic Medicine, Fetal Medical Centre, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
Prenat Diagn. 2014 Jun;34(6):564-9. doi: 10.1002/pd.4349. Epub 2014 Mar 18.
This study aimed to assess the fetal conus medullaris (CM) position with three-dimensional (3D) ultrasonography and its use in detecting and diagnosing spina bifida occulta (SBO).
We examined 150 normal fetuses (gestational age, 20-38 weeks) and 14 fetuses with SBO. All fetuses underwent prenatal 3D ultrasonography, and the CM position in relation to the vertebral body was evaluated using volume contrast imaging. Intra- and inter-observer agreements were assessed using weighted kappa. The correlation between gestational age and CM level was determined by linear regression analysis.
Operators successfully located the CM position in 145 cases. The CM was at L3 or higher in all normal group cases. A linear relationship was noted between gestational age (X) and CM position (Y) (Y = 0.118X + 6.011, R(2) = 0.679, P < 0.001). The weighted kappa values for intra- and inter-observer agreement were 1.0 and 0.788, respectively. The CM was located at L3 in one case and lower than L3 in 13 cases in the SBO group. All values were below the fifth percentile for the normal group.
Three-dimensional ultrasonography may accurately determine the CM vertebral level. Prenatal evaluation of the CM position may improve the detection and diagnosis of SBO.
本研究旨在利用三维超声评估胎儿圆锥（CM）位置及其在隐性脊柱裂（SBO）检测和诊断中的应用。
我们检查了150例正常胎儿（孕周20 - 38周）和14例患有SBO的胎儿。所有胎儿均接受产前三维超声检查，并使用容积对比成像评估CM相对于椎体的位置。观察者内和观察者间的一致性采用加权kappa进行评估。通过线性回归分析确定孕周与CM水平之间的相关性。
操作者成功定位CM位置145例。所有正常组病例中CM位于L3或更高水平。观察到孕周（X）与CM位置（Y）之间存在线性关系（Y = 0.118X + 6.011，R² = 0.679，P < 0.001）。观察者内和观察者间一致性的加权kappa值分别为1.0和0.788。SBO组中1例CM位于L3，13例低于L3。所有数值均低于正常组的第五百分位数。
三维超声可准确确定CM椎体水平。产前评估CM位置可能改善SBO的检测和诊断。
