胎儿颜面轮廓的超声研究

【作者】 武玺宁；

【导师】 姜玉新；

【作者基本信息】 北京协和医学院 ， 影像医学与核医学， 2014， 博士

【摘要】 目的应用二维及三维超声测量多个颜面相关指标评估胎儿颜面轮廓,并比较两种方法的测量稳定性,对初步建立中国人群正常胎儿的颜面轮廓生长发育趋势进行尝试性研究。资料与方法2013年4月-2014年2月期间于我院进行产科超声检查的孕11周～38周孕妇共439例。联合评估胎儿颜面轮廓的各项指标：1.确定测量切面即颜面正中矢状面的标志性结构；2.测量鼻骨长度(nasal bone length,NBL)、鼻前组织厚度(prenasal thi-ckness,PT),并计算PT/NBL；3.确定颜面轮廓线(facial profile line,FPL)的三种分型,即零,阴性和阳性,阳性时测量FPL到额骨外缘的距离F；4.规范各颜面角度如额-上颌角(frontomaxillary facial angle,FMF)、额-鼻角(frontonasal angle,FNA)、上下颌面角(mandibulomaxillary facial angle,MMF)、上颌-鼻根-下颌角(maxilla-nasion-mandible angle, MNM)的定义。在最先获取的100个样本中随机抽取30例进行二维和三维之间的测量一致性分析；并对两种方法在不同测量者间,及同一测量者内的不同次测量间,进行测量稳定性的分析。选取稳定性良好且操作简单的方法进行所有胎儿颜面结构的测量。建立初步的胎儿颜面轮廓发育趋势,并分析颜面轮廓与孕周(gestational age,GA)的关系。结果1、一致性分析：30例样本均分析NBL、PT、PT/NBL、FMF、FNA、MMF和MNM,上述各测量指标二维与三维测量方法的组内相关系数(intra-class correlationcoefficient,ICC)分别为0.984、0.985、0.751、0.780、0.838、0.760、0.729；二维超声在同一测量者不同次测量之间的ICC分别为0.994、0.994、0.741、0.891、0.963、0.887、0.954；二维超声在不同测量者间的ICC分别为0.982、0.890、0.708、0.815、0.903、0.811、0.917：三维超声在同一测量者不同次测量之间的ICC分别为0.997、0.996、0.878、0.968、0.962、0.974、0.988；三维超声在不同测量者间的ICC分别为0.994、0.991、0.746、0.948、0.905、0.874、0.889。对于FPL,二维及三维方法评估显示分类结果一致。2、胎儿NBL与PT随孕周而增大,其关系方程式符合S曲线,方程分别为：NBL=e3.097-30.563/GA, PT=e2.703-30.093/GA;PT/NBL在整个孕周保持稳定,平均值为0.70。3、正常胎儿FPL无“阴性”结果。多数结果为“零”,占92.26%,“阳性”结果占7.74%,集中在11-13周及26-38周,“阳性”时测量F值范围0.10-0.51cm(0.24±0.10cm)。4、胎儿各颜面角度发育与孕周相关,关系方程式均符合三次多项式：FMF角与孕周呈负相关,方程式：FMF角=135.300-6.473×GA+0.235×GA2-0.003×GA3(R2=0.240,P=0.000)；FNA与孕周呈正相关,方程式：FNA=58.920+7.452xGA-0.274×GA2-0.003×GA3(R2=0.297, P=0.000); MMF角与孕周呈负相关,方程式：MMF=132.329-5.337xGA+0.191×GA2-0.002xGA3(R2=0.304, P=0.000);MNM角与孕周呈正相关,方程式：MNM=-24.592+4.653×GA-0.173×GA2+0.002xGA3(R2=0.413,P=0.000)。结论1、对颜面轮廓各指标定义进行规范后,三维超声评估胎儿颜面轮廓的观察者内及观察者间一致性较好,临床应用中具有明显优势2、胎儿鼻骨长度及鼻前组织厚度与孕周密切相关,随孕周呈S曲线增长,鼻前组织厚度与鼻骨长度之比在整个孕周保持稳定3、正常胎儿颜面轮廓线无“阴性”表现4、胎儿颜面角度变化与孕周相关,曲线拟合三次多项式相关程度最高目的回顾分析染色体异常胎儿颜面轮廓的特点,评估颜面轮廓相关指标对染色体异常的提示价值资料与方法病例组选取2008年3月-2013年1月期间于我院进行产科超声检查并有明确染色体结果的胎儿共26例,其中21-三体21例,18-三体5例。对照组随机选取正常胎儿325例。回顾分析胎儿颜面正中矢状面图像,联合评估颜面轮廓的各项指标：1..测量鼻骨长度(nasal bone length, NBL)、鼻前组织厚度(prenasal thickness,PT),并计算PT/NBL；2.确定颜面轮廓线(facial profile line,FPL)的三种分型,即零,阴性和阳性,阳性时测量FPL到额骨外缘的距离F；3.规范各颜面角度如额-上颌角(frontomaxillary facial angle,FMF)、额-鼻角(frontonasal angle,FNA)、上下颌面角(]mandibulomaxillary facial angle,MMF)、上颌-鼻根-下颌角(maxilla-nasion-mandible angle,MNM)的定义。将上述颜面轮廓的各相关指标与对照组正常胎儿各参考值范围进行对比分析,评估染色体异常胎儿与正常胎儿之间的差异。结果1、21-三体胎儿21例21-三体胎儿中,11例鼻骨缺失,余10例胎儿的NBL与对照组正常胎儿无明显差异(P>0.05)。21-三体胎儿PT明显增厚,平均值为5.67mm,与正常胎儿的平均值4.21mm存在显著差异(P<0.05),并且76.2%(16/21)高于正常胎儿第95百分位数。存在鼻骨的10例21-三体胎儿计算PT/NBL,平均值为1.21,明显大于正常胎儿的平均值0.69(P<0.05)。21-三体胎儿FPL14例为“零”,4例“阳性”(F值0.23-0.55cm),3例“阴性”。3例FPL“阴性”的胎儿存在前额扁平。21-三体胎儿与正常胎儿在FMF角与MNM角之间存在显著差异(P<0.05)。在21-三体胎儿中,95.2%(20/21)的FMF角大于正常胎儿的平均值,38.1%(8/21)大于正常胎儿的第95百分位数；85.7%(18/21)的MNM角小于正常胎儿的平均值。2、18-三体胎儿5例18-三体胎儿中,NBL、PT及PT/NBL与正常胎儿无明显差异(P>0.05)。18-三体胎儿2例FPL为“零”,3例“阴性”,无“阳性”结果。3例FPL“阴性”的胎儿均存在小下颌。18-三体胎儿与正常胎儿在MMF角与MNM角之间存在显著差异(P<0.05)。在18-三体胎儿中,100%(5/5)的MMF角小于正常胎儿的平均值,40%小于正常胎儿的第5百分位数；100%(5/5)的MNM角大于正常胎儿的平均值,40%大于正常胎儿的第95百分位数。结论1、颜面正中矢状面可为筛查胎儿染色体异常提供多个信息,该切面应作为中孕超声筛查的常规内容2、鼻骨及鼻前组织厚度的测量对于21-三体的筛查意义明确,FMF及MNM角有助于提示颜面扁平,可作为筛查21-三体的辅助超声标记3、MMF及MNM角可提示小下颌,对诊断18-三体具有一定意义4、FPL可初步判断胎儿前额及下颌异常更多还原

【Abstract】 ObjectiveTo evaluate some ultrasound markers of the fetal facial profile with two-dimensional and three dimensional ultrasound, and to compare the reliability of both of the two methods. To construct a preliminary reference of normal fetal facial profile in Chinese population.MethodsFrom2013April to2014February,439singleton fetuses ranged between11and38weeks of gestation were enrolled in this study.The indicators of facial profile were defined:1.confirm the details of mid-sagittal plane of facial profile;2.measurements of nasal bone length (NBL) and prenasal thickness (PT) were obtained, then calculate the PT/NBL ratio;3. facial profile line (FPL) was defined as’zero’,’negative’or’positive’, repectively. When the FPL was’positive’ the F distance between the FPL and the frontal bone wea measured.4.confirm the definition of frontomaxillary angle (FMF), frontonasal angle (FNA), mandibulomaxillary angle (MMF), maxilla-nasion-mandible angle (MNM).The intra-and interobserver reliability of different sonographic methods was calculated in30cases.Three dimensional(3D) ultrasonographic method was used for its good reliability and convenience to evaluate fetal facial profile of all enrolled fetuses.Pearson’s correlation coefficient, curve estimation and polynomial regression models were used to evaluate the correlation of the indicators of fetal facial profile with gestational age (GA).Results1. As to NBL, PT, PT/NBL, FMF, FNA, MMF, MNM, intra-class correlation coefficient(ICC)between2D and3D wereO.984、0.985、0.751、0.780、0.838、0.760and0.729, respectively. Intraobserver ICC of2Dwere0.994、0.994、0.741、0.891、0.963、0.887and0.954, respectively. Interobserver ICC of2D wereO.982、0.890、0.708、0.815、0.903、0.811and0.917, respectively. Intraobserver ICC of3D were0.997、0.996、0.878、0.968、0.962、0.974and0.988, respectively. Interobserver ICC of3D wereO.994、0.991、 0.746、0.948、0.905、0.874and0.889, respectively.Either2D or3D method, the same classification on result of FPL was shown to prove the consistency of the two methods is good.2. Using GA as the independent variable and NBL and PT as the dependent variables, the best fit regressing equation was NBL=e3097-30.563/GA, PT=e2.703-30.093/GA.The Pearson’s correlation coefficient between NBL and PT with GA were0.961and0.945, respectively. The PT/NBL ratio was stable throughout gestation, with a mean of0.70.3. No cases with a negative FPL were found in all of fetuses. Most commonly seen was an FPL with position zero(92.26%). The FPL was positive in up to7.74%, and the mean F distance was0.24cm(range,0.10-0.51cm).4. Using GA as the independent variable and the facial angles as the dependent variables, the best fit regressing equation was FMF(°)=135.300-6.473×GA+0.235xGA2-0.003xGA3(R2=0.240, P=0.000); FNA(°)=58.920+7.452×GA-0.274xGA2-0.003xGA3(R2=0.297, P=0.000); MMF(°)=132.329-5.337xGA+0.191xGA2-0.002xGA3(R2=0.304, P=0.000); MNM(°)=-24.592+4.653xGA-0.173xGA2+0.002xGA3(R2=0.413, P=0.000).The Pearson’s correlation coefficient between FMF, FNA, MMF and MNM with GA were-0.369,0.447,-0.470and0.386, respectively.Conclusion1.Three dimensional ultrasound evaluation the fetal facial profile had an excellent reliability.2.NBL and PT were highly correlated with GA, PT/NBL ratio was stable throughout gestation.3. No cases with a negative FPL were found in normal fetuses.4.The growing patterns of fetal facial angles fitted with a cubic polynomial function. ObjectiveTo investigate the characteristics of facial profile in chromosomally abnormal fetuses, and to determine its diagnostic value for genetic disorder.MethodsIn a retrospective study, the stored images from March2008to January2013were reviewed for the comparison of the facial profile between26pathologic fetuses with21trisomy-21and5trisomy-18(study group) with325normal fetuses selected randomly (control group).We evaluate a number of indicators of facial profile in the mid-sagittal plane:1.measurements of nasal bone length (NBL) and prenasal thickness (PT) were obtained, then calculate the PT/NBL ratio;2. facial profile line (FPL) was defined as’zero’,’negative’or’positive’, repectively. When the FPL was’positive’the F distance between the FPL and the frontal bone wea measured.3.confirm the definition of frontomaxillary angle (FMF), frontonasal angle (FNA). mandibulomaxillary angle (MMF), maxilla-nasion-mandible angle (MNM).These indicators of each case were measured and compared with the ones of normal fetuses.The diagnostic value of the indicators were examined.Results1、trisomy21There were21trisomy21,11fetuses had absent nasal bone, while there was no significant difference between the other10trisomy21with the normal fetuses (P>0.05).In the trisomy21fetuses the mean PT and PT/NBL ratio were5.67mm and1.21respectively, which were significantly larger than in normal fetuses, with the mean of PT and PT/NBL ratio were4.21mm and0.69, respectively (P<0.05).The PT was above the95th percentile in76.2%(16/21)of the trisomy21fetuses.14cases of trisomy21showed the FPL’zero’, and3cases were positive FPL with the F distance from0.23cm to0.55cm.3cases with sloping forehead with negative FPL. Among trisomy21,20of21(95.2%)FMF angle was larger than the mean of the normal range, and38.1%(8/21) of FMF was above the95th percentile of the normal fetuses;18of21(85.7%)MNM angle was smaller than the mean of the normal range.2、Trisomy18In the5fetuses with trisomy18, the NBL, PT and PT/NBL ratio were not significantly different from normal.There was no cases showed positive FPL.2cases showed FPL ’zero’, and3cases with micrognathia had negative FPL.There were significant difference in the MMF and MNM angles between the trisomy18fetuses and normal fetuses.In trisomy18fetuses, all of the5cases had smaller MMF angel and larger MNM angle than normal ones. The MMF angle was below the5th percentile in40%(2/5) of the trisomy18fetuses, and the MNM angle was above the95th percentile in40%(2/5) of the trisomy18ones.Conclusion1.Facial midsagittal plane may contribute to prenatal detection of chromosomal abnormality and need to be routinely examined during second-trimester screening.2.The NBL and PT measurement can be used to screen trisomy21in second trimester. Measurement of the FMF and MNM angles is likely to prove a useful method in prenatal screening for trisomy21in the second trimester.3.MMF and MNM angle are helpful for detection of micorgnathia, which is commonly associated with trisomy18.4. The FPL may be a useful tool to detect second trimester profile anomalies such as sloping forehead and micrognathia.更多还原