Ultrasound Fetal Facial Profile

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.