三维超声联合VCI、TUI技术观察脊髓圆锥对胎儿骶尾部疾病合并脊髓拴系综合征的诊断价值

Value of ultrasonography in diagnosis of spinal cord conus in fetal sacral tail disease complicated with tether

摘要:

目的 探讨超声观察胎儿脊髓圆锥对胎儿骶尾部疾病合并脊髓拴系综合征的诊断价值。方法 选取2014年3月—2020年6月保定市第一中心医院接受常规及孕中期产前超声检查为正常单胎的66例胎儿作为正常组，另选取同期该院行产前超声检查诊断为胎儿脊髓圆锥位置低下，可疑胎儿脊髓发育异常，出生后经磁共振成像或引产后解剖病理证实为脊髓发育异常的14例胎儿作为异常组。使用三维超声容积对比成像（VCI）和断层超声成像（TUI）技术定位两组的脊髓圆锥和脊髓腰膨大对应椎体位置；测量胎儿的脊髓圆锥-第一骶椎距离（CM-S1）、脊髓腰膨大横径和前后径。Pearson法分析孕周与胎儿CM-S1距离、脊髓腰膨大横径和前后径的相关性。结果 正常组孕中期胎儿脊髓圆锥末端对应椎体位于L₃水平的比例高于孕晚期胎儿（P <0.05），孕中期胎儿脊髓腰膨大对应椎体位于L₁水平的比例高于孕晚期胎儿（P <0.05）；正常组不同孕周胎儿的CM-S1距离比较，差异有统计学意义（P <0.05），CM-S1距离随孕周的增加而增加，且正常组不同孕周胎儿的CM-S1距离均高于相应孕周第5百分位数；正常胎儿和脊髓异常胎儿的CM-S1距离与孕周呈线性相关（r =0.552和0.509，均P <0.05）；正常组和异常组不同孕周胎儿的脊髓腰膨大前后径比较，差异有统计学意义（P <0.05），异常组各阶段孕周胎儿的脊髓腰膨大前后径小于正常组胎儿；Pearson法分析结果显示，正常组和异常组胎儿的CM-S1距离、脊髓腰膨大横径、脊髓腰膨大前后径与孕周呈正相关（均P <0.05）。结论 三维超声结合VCI、TUI技术可用于筛查正常胎儿与骶尾部疾病合并脊髓拴系综合征胎儿，异常胎儿的脊髓圆锥对应椎体水平较正常胎儿低，CM-S1距离较正常胎儿短，行产前超声检查时可参考以上指标初步筛查脊髓异常胎儿。

Abstract:

Objective To study the value of ultrasonography in the diagnosis of spinal cord conus in fetal sacral tail disease complicated with tether.Methods From March 2014 to June 2020, 66 normal singleton fetuses who received routine and mid-trimester systematic ultrasound examination in the Outpatient department of East Hospital of Baoding First Central Hospital were selected as the normal group. During the same period, they were selected to receive prenatal systematic ultrasound screening for the diagnosis of low position of fetal spinal conus and suspected abnormal development of fetal spinal cord. Fourteen fetuses with abnormal spinal cord development confirmed by magnetic resonance or induced labor were included in the abnormal group. Three dimensional ultrasound volume contrast imaging (VCI) and tomography ultrasound imaging (TUI) were used to locate the corresponding vertebral bodies of conus spinal cord and lumbar enlargement in the two groups. The distance between the conus medullae and the first sacral vertebra (CM-S1), transverse diameter of spinal lumbar enlargement, and anteropoor-posterior diameter were measured in both groups. The person correlation coefficient was used to analyze the correlation between gestational age and fetal CM-S1 distance, transverse diameter, and anterior-posterior diameter of spinal cord and lumbar enlargement.Results The proportion of conus medullaris terminal at L₃ level in normal fetuses in the second and third trimester was statistically significant (P < 0.05). The proportion of conus medullaris terminal at L₃ level in normal fetuses in the second trimester was higher than that in the third trimester. There was statistically significant difference in the proportion of vertebral end located at L₁ level between the second and third trimester of normal fetuses (P < 0.05). The proportion of vertebral end located at L₁ level corresponding to spinal cord lumbar enlargement in the second trimester of normal fetuses was higher than that in the third trimester. The CM-S1 distance in the normal group was 13.56 to 44.11 mm, and the average distance was (28.96 ± 8.15) mm. F-test showed that the CM-S1 distance increased with the increase of gestational age, and the difference was statistically significant (P < 0.05). In addition, the CM-S1 distance in the normal group was higher than the fifth percentile of gestational age. The CM-S1 distance of normal fetus was linearly correlated with gestational age (r = 0.552, P = 0.006), There was a linear correlation between CM-S1 distance and gestational age in fetuse with spinal cord abnormalities (r = 0.509, P = 0.014). T test showed that there were statistically significant differences in the diameter of lumbar enlargement of the spinal cord between the normal group and the abnormal group at different gestational weeks (P < 0.05). The anterior and posterior diameter of lumbar enlargement in abnormal group was smaller than that in normal group at each gestational week. Pearson correlation analysis showed that the CM-S1 distance, transverse diameter of lumbar enlargement of spinal cord, anterior and posterior diameter of lumbar enlargement of spinal cord were positively correlated with gestational age between normal group and abnormal group (all P < 0.05).Conclusion Three-dimensional ultrasound combined with VCI and TUI technology can be used to screen normal fetuses and fetuses with sacrococcygeal disease complicated with cord tetetation. Compared with normal fetuses, the level of vertebral body corresponding to the conus of spinal cord of abnormal fetuses is lower and the distance of CM-S1 is shorter. In prenatal ultrasound system examination, the above indicators can be referred to for preliminary screening of fetuses with spinal cord abnormalities.