A total of 900 normal fetuses and 146 fetuses with closed spinal dysraphism or tethered cord syndrome were included in this study. The N values were tallied and compared along the spinal longitudinal plane. The receiver operating characteristic curve was utilized, and the cut-off value of N was analyzed.
The counting of N was successfully performed in 856 normal and 146 abnormal fetuses. In the normal group, an increase in N with gestational age was observed. Specifically, in the subgroup of 17-20 wk fetuses, N was ≥6 in 117 out of 131 cases. This figure increased to 211 out of 213 in 21-24 wk and 512 out of 512 in 25-41 wk, respectively. Cases with N ≥7 accounted for 715 out of 856 fetuses in the 17-41 wk range. In the abnormal group, N was less than 7 in 152 out of 163 fetuses, showing statistical differences between the two groups. With a cut-off value of 6.5, specificity and sensitivity reached 93.3% and 83.5%.
The counting of N was found to be a straightforward and efficient method for evaluating the position of the conus medullaris.
方法:本研究共纳入了900名正常胎儿和146名患有闭合性脊髓发育不良或脊髓栓系综合征的胎儿。沿脊柱纵向平面计算并比较N值。利用接收器工作特性曲线,并对N的截断值进行了分析。
结果:在856例正常胎儿和146例异常胎儿中成功进行了N计数。在正常组,观察到N随胎龄增加。具体来说,在17-20周胎儿亚组中,131例中117例,N≥6。这一数字在21-24周增加到213人中的211人,在25-41周增加到512人中的512人,分别。在17-41周范围内,N≥7的病例占856例胎儿中的715例。在异常组中,在163个胎儿中,N小于7/152,显示两组之间的统计学差异。截断值为6.5,特异性和敏感性分别为93.3%和83.5%。
结论:发现N的计数是评估延髓圆锥位置的一种直接有效的方法。