胎儿腰椎长度发育与孕龄及性别相关性3.0T磁共振研究

Study on correlation between the fetal lumbar spine length and gestational age and sexual dimorphisms by 3.0T MR

目的利用3.0T磁共振研究正常胎儿标本腰椎长度随孕周增加的变化规律及不同性别间差异,绘制腰段脊柱生长曲线。方法利用3.0T MR扫描仪对71例16~42周自然流产及因母体或胎儿因素引产的胎儿新鲜标本行全脊柱3D-T2WI序列扫描,对所得图像以L2椎体为中心进行三方位重建,在正中矢状位上测量腰椎长度,对测量参数和孕周作回归分析,并比较测量参数在性别间的差异。结果胎儿腰椎长度在16~42周从（1.96±0.13）cm增加到（5.54±0.42）cm,长度与孕周均呈直线相关,线性回归方程为：腰椎长度（cm）=-0.401＋0.147×孕周,R2=0.98,P〈0.05;腰椎长度发育不存在性别差异。结论孕中晚期胎儿腰椎长度随孕周增加发育迅速,与胎龄呈高度直线相关性,与性别间无明显相关性,腰椎长度是评估胎儿胎龄及生长发育状况的可靠指标。

Objective Using the magnetic resonance imaging（MRI）to research the normal fetal lumbar spine length at varying gestational ages and sex dimorphisms,we investigated a more sensitive nomogram of fetal spine length and gestational ages.Methods This research was a prospective study.Postmortem MR imaging was performed on 71 fetuses,ranging between 16~42 gestational ages.3D-T2 WI of the whole spine was performed in sagittal planed,and then reconstructd in the coronal,sagittal and axial planed based the L2 vertebra,to measure the length of the lumbar spine in the midcogtal planed.Liner regression equation was established.And the developmental changes with sexual dimorphisms were analyzed.Results A statistically significant increase in all measurements was found with advancing gestational age.The length of lumbar spine increased linearly from（1.96±0.13）to（5.54±0.42）cm for the 16-week and 42-week groups of gestation,respectively,the function was represented by the regression.The lumbar segment length was-0.401＋0.147×gestational age,R^2=0.98,Sexual dimorphisms was not detected.Conclusion The fetal spine length appears as an easily acquired and valuable parameter,which strongly correlates with gestational age.No significant differences were observed in the values for the parament studued according to sex.Therefor,lumbar spine length is the best predictor of gestational age among the parameters.It is useful in assessing morphologic maturity of fetuses.