摘要目的 测量不同孕周正常胎儿脊髓圆锥末端与最末椎体骨化中心尾侧端之间的距离(D1)和脊髓圆锥末端至D1延长线与尾侧皮肤交点间的距离(D2),研究2个测值对产前超声诊断脊髓拴系综合征(TCS)的价值.方法 选择15~41孕周正常胎儿974例(正常组)和 TCS胎儿46例(异常组),测量各胎儿的D1和D2.正常组中随机抽取60例胎儿,进行医师间重复测量结果的信度分析;分析D1、D2与孕周(GA)的相关性,并建立各孕周正常胎儿脊髓圆锥末端D1、D2的参考值范围;评估两组间D1和D2的差别;分析两组间常用生长参数(双顶径、头围、腹围和股骨)与D1、D2的比值,探讨D1、D2及各比值对胎儿闭合性脊柱裂的诊断价值.结果 ①不同医生间测量的重复性良好;②D1、D2均与GA具有相关性且呈线性相关,线性拟合方程分别为D1=0.251 GA -2.265 cm(R2=0.926,P <0.001),D2=0.267 GA -1.812 cm(R2=0.928,P <0.001); ③正常组与异常组D1、D2差异均有统计学意义(P <0.001); ④各生长参数与D1与D2的比值较稳定,且两组间差异均有统计学意义(P <0.001).结论 超声测量脊髓圆锥D1和D2简便可行,两测值均有助于产前诊断TCS.

abstractsObjective To evaluate the position of the fetal conus medullaris during pregnancy and its value in detecting tethered cord syndrome(TCS). Methods Nine hundred and seventy-four normal fetuses and 46 fetuses with TCS between 15 and 41 weeks gestation were involved in the study.Parameters D 1 (the distance between the end of the conus medullaris and the caudal edge of last vertebral body ossification center) and D2 (the distance from the end of the conus medullaris to the caudal skin namely the intersection point of the extending line of D1 and the skin) were measured in the caudal midsagittal plane of the spine. Sixty normal fetuses were chosed randomly for interobserver variability.Correlation analysis between these two parameters and gestational age(GA) were conducted and the normal reference value of these parameters were calculated in normal group. The ratios of growth parameters ( Biparietal diameter, Head circumference,Abdominal circumference,Femur length) to D1 and D2 were calculated separately to observe the difference of the ratios between two groups. All the parameters and ratios of normal fetuses were compared with that of TCS cases.Results There was no significant difference in D1 and D2 between two observers.A significant linear correlation between the parameters and GA was found in normal group,linear regression equations were D1=0.251 GA -2.265 cm (R2=0.926,P <0.01) and D2=0.267 GA -1.812 cm(R2=0.928,P <0.01),respectively.D1 and D2 were much lower in normal group than in abnormal group (all P <0.01). The ratios of the growth parameters to D1 and D2 were relatively stable and had statistically differences between two groups in different gestational age. Conclusions The methods that determination of D1 and D2 are simple and feasible,and could help to the prenatal diagnosis of TCS.