正常胎儿标本颈、胸、腰段脊柱发育的MRI研究

目的探讨正常胎儿标本颈、胸、腰段脊柱和椎体体积随孕周生长变化规律。方法利用3.0 T MR扫描仪对55具17~42孕周胎儿尸体标本行全脊柱三维T2WI序列扫描,其中孕妇自发性流产获得标本20具,母体因严重疾病引产获得标本35具,胎儿标本均来源于山东大学医学院断层影像解剖学研究中心。标本经CT扫描均未发现脊柱异常。采用OsiriX软件(www.osirix-viewer.com),在重建横断面图像上沿椎体边缘逐层勾画椎体轮廓,获得脊柱颈、胸、腰段脊柱体积,将其除以各段椎体个数,获得椎体单位体积。逐一测量腰椎5个椎体体积。将颈、胸、腰段脊柱体积和腰椎椎体体积与孕周作回归分析,并分析各段脊柱增长规律。结果(1)胎儿颈、胸、腰段脊柱体积与孕周增长呈线性相关关系,线性回归方程分别为:颈段脊柱体积(mm3)=-1260.937+81.235×孕周(R2=0.974,P<0.05);胸段脊柱体积(mm3)=-5933.521+347.503×孕周(R2=0.972,P<0.05);腰段脊柱体积(mm3)=-5130.912+294.473×孕周(R2=0.976,P<0.05)。(2)胎儿脊柱生长速度:胸段>腰段>颈段;同一孕周阶段内,脊柱体积:胸段>腰段>颈段;椎体单体积增长速度及增长倍数:腰椎>胸椎>颈椎。(3)腰1~腰5椎体体积增长与孕周亦呈线性相关关系。结论孕中晚期胎儿标本颈、胸、腰段脊柱椎体体积的增长与胎龄呈良好的相关性,且不同节段生长速度不一。

MRI study on the normal fetal development of cervical,thoracic and lumbar spines in specimens

Objective To assess the change rules of fetal cervical,thoracic and lumbar spinal volume and centrum volume with gestational ages.Methods The 3.0 T MRI was performed on 55 fetal specimens ranging from 17 to 42 gestational weeks with sequence of three dimensional T2WI.Among 55 samples,20 samples were obtained from spontaneous abortion of pregnant women and 35 samples were obtained from induced labor of mothers due to serious diseases.The fetal specimen was derived from sectional imaging anatomy research institute of the medical school of Shandong University.No spinal abnormalities were found on CT scans.The cervical,thoracic and lumbar spinal volume was obtained by delineating the vertebral body contour on the reconstructed cross-sectional image with the OsiriX software(www.osirix-viewer.com).And the volume of the cervical,thoracic and lumbar spine was divided by the number of the vertebral bodies to obtain the centrum unit volume.Five lumbar vertebral bodies were measured one by one.Regression analysis was made between the volume of cervical,thoracic and lumbar spine and gestational weeks,and between the volume of lumbar vertebral bodies and gestational weeks to analyze the growth rule of spine.Results(1)The cervical,thoracic and lumbar spine volume increased linearly with gestational ages,and the linear regression equation was as follows:cervical spine volume(mm3)=-1260.937+81.235×gestational week(R2=0.974,P<0.05),thoracic spine volume(mm3)=-5933.521+347.503×gestational week(R2=0.972,P<0.05),lumbar spine volume(mm3)=-5130.912+294.473×gestational week(R2=0.976,P<0.05).(2)The order from large to small of fetal spinal growth rate was thoracic,lumbar and cervical segment.Within the same gestational age,the order from large to small of spinal volume was thoracic,lumbar and cervical segment.The order from large to small of centrum unit volume growth rate was lumbar,thoracic and cervical vertebrae.(3)The volume of each lumbar vertebral body also increased linearly with gestational age.Conclusion The cervical,thoracic and lumbar volume show a good correlation with the gestational weeks in the second and third trimester fatal specimens,and the growth rate of different segments is different.