新型智能产前超声技术在中晚孕期产前超声检查中的应用价值

目的探讨新型智能产前超声技术（SF）技术包括标准切面自动识别与获取（SFDA）技术和生长参数自动测量（SFM）技术的临床使用价值。 方法使用SF技术和传统超声技术对2018年8月至2019年1月南方医科大学附属深圳妇幼保健院妊娠16~41周正常连续单胎1005例进行丘脑水平横切面（A）、上腹部水平横切面（B）和股骨长轴切面（C）3个标准切面的识别与获取,测量双顶径（BPD）、头围（HC）、腹围（AC）和股骨长（FL）4个生长参数。另选择60例胎儿进行2种技术观察者内和观察者间重复性测量分析;运用Wilcoxon带符号秩检验比较2种技术进行切面识别与获取以及参数测量所需的时间;使用组内相关系数评价传统超声与SF技术测量的一致性,并评价SF技术切面获取及生长参数测量的准确率。 结果与传统超声技术相比,SF技术测量的重复性更好。使用SF与传统技术测量4个生长参数的组内相关系数分别为0.998、0.995、0.998、0.998。通过判定,使用SF技术识别与获取标准切面A、B和C成功率分别为98.00%、99.10%和99.60%,测量BPD、HC、AC和FL成功率分别为100%、100%、99.60%和100%。无论是同时进行切面自动识别、获取与参数测量,还是单独进行参数测量时,SF技术明显比传统技术用时短[21.26（5.24）s vs 52.24（14.90）s;2.78（0.66）s vs 35.70（8.25）s],差异均具有统计学意义（Z=-27.366、-27.352,P均<0.001）。 结论SF技术可自动化、智能化识别、获取胎儿超声3个标准切面,并对4个生长参数进行自动化测量,该技术在切面识别与获取的成功率和生长参数自动测量的准确性高,并可极大地减少标准切面获取及测量的时间,是一项智能、精准、高效的产前超声检查技术。     

Determination of gestational age after the 24th week of gestation from fetal kidney length measurements.

OBJECTIVE: To evaluate the application of kidney length measurement to the determination of gestational age between the 24th and 38th weeks and to compare its accuracy with that of other fetal biometric indices. STUDY DESIGN: Seventy-three women with singleton uncomplicated pregnancies underwent standard ultrasound fetal biometry and kidney length measurement every 2 weeks between 24 and 38 weeks' gestation. These measurements were used to date the pregnancies relative to crown-rump length dating between 8 and 10 weeks' gestation. Linear regression models for estimation of gestational age were derived from the biometric indices and kidney length. In addition, stepwise regression models were constructed to determine the best model for determining gestational age between 24 and 38 weeks. Comparisons were then made between the accuracy of these models in the determination of gestational age. RESULTS: The best model for estimating gestational age in late pregnancy included the variables kidney length, biparietal diameter, head circumference, femur length and abdominal circumference. This model accurately predicted gestational age with a standard error of +/- 8.48 days. A model including kidney length, biparietal diameter, head circumference and femur length accurately predicted gestational age with a standard error of +/- 8.57 days. These models were slightly more accurate than models derived from the biometric indices of biparietal diameter, head circumference and femur length (+/- 9.87 days), biparietal diameter, head circumference, femur length and abdominal circumference (+/- 9.45 days) and biparietal diameter and femur length (+/- 9.9 days). Kidney length and femur length were the most accurate single parameters for predicting gestational age using simple linear regression models (+/- 10.29 and 10.96 days, respectively); the abdominal circumference was the least accurate (+/- 14.54 days). CONCLUSION: Kidney length is a more accurate method of determining gestational age than the fetal biometric indices of biparietal diameter, head circumference, femur length and abdominal circumference between 24 and 38 weeks' gestation. When combined with biparietal diameter, head circumference and femur length, the precision of dating is improved by 2 days. This measurement is easy to make and could therefore be easily incorporated into the model for dating pregnancies after 24 weeks of gestation, in particular when measurements of the biparietal diameter and head circumference are difficult.     

Customizing fetal biometric charts.

OBJECTIVE: To study the effects of maternal and pregnancy characteristics on fetal biometric size using longitudinal ultrasound measurements and to construct customized models for fetal biometric size charts. METHODS: A cohort of 533 healthy pregnant women with normal singleton pregnancies were recruited for regular ultrasound examination for fetal biometry between 24 and 40 weeks' gestation. Multilevel modeling was used to construct models of fetal head size, femur length and abdominal circumference. Variables of maternal and pregnancy characteristics including booking weight and height, age, parity and fetal sex were included in the construction of the customized fetal biometric size charts. RESULTS: Increased fetal head size and abdominal circumference were significantly associated with extremes of maternal age. Maternal height had a statistically significant influence on biparietal diameter. Maternal booking weight had an influence on fetal abdominal circumference and femur length. Fetal sex was found to have a statistically significant influence on the final regression models of biparietal diameter, head circumference and femur length. Parity had an influence on fetal head circumference and abdominal circumference. CONCLUSIONS: Maternal and pregnancy characteristics have a significant influence on in-utero fetal biometry. We produced models to construct customized fetal biometric size charts. Further validation studies are necessary to evaluate the clinical usefulness of such customized fetal biometric size charts.     

胎儿小脑横径与孕龄的相关性探讨

本文应用实时线阵超声对７５０例妊娠１６～４０周的正常孕妇的胎儿小脑横径（ＣＴＩ））、双顶径（ＢＰＤ）、头围（ＨＣ）、腹围（ＡＣ）及股骨长度（ＦＬ）进行测量，线性相关分析结果显示ＣＴＩ）、ＢＰＤ、ＨＣ、ＡＣ及ＦＬ均与孕龄（ＭＡ）呈高度的正相关，以ＣＴＤ的相关性最好，小脑位于后颅窝内，因后颅窝特定的解剖特点，使小脑形状不受外界因素的影响，故用ＣＴＤ推算孕龄更为准确，并能在胎儿期及早发现中枢神经系统异常，对围产监测具有重要的意义，提出超声测量胎儿小脑横径可作为估计孕龄的可靠指标之一。     

Measurement of limb circumferences with three-dimensional ultrasound for fetal weight estimation.

A large number of formulae have been published for fetal weight estimation. This study examines the possibility of using three-dimensional ultrasound to measure the limb circumference. This technology provides us with the opportunity to visualize two simultaneous, orthogonal planes, allowing the exact determination of the transverse plane at the mid-point of the limb. A total of 157 patients were scanned in the week prior to delivery. The following variables were measured in 154 fetuses: biparietal diameter, head circumference, transverse abdominal diameter, abdominal circumference, femur length, thigh circumference and arm circumference. The whole population was split into three subgroups according to the abdominal circumference centile (< 10th centile, 10-90th centile, and > 90th centile), because this single variable has the strongest correlation with neonatal weight (R = 0.901). With forward stepwise multiple regression analysis, four models were elaborated, one for the whole population and one for each subgroup. The small-for-dates fetuses need a targeted formula including only two variables, thigh circumference and femur length. Our data suggest that the thigh circumference measurement improves the estimation for growth-retarded fetuses and that the arm circumference improves the weight prediction for the others. The measurement of the two variables, made possible with three-dimensional ultrasound, has improved our results in fetal weight estimation.     

Intraobserver and interobserver reproducibility of fetal biometry.

OBJECTIVE: To assess the intra- and interobserver reproducibility of ultrasound measurements of fetal biometric parameters. METHODS: We assessed the intraobserver and the interobserver agreement in measurements of fetal biparietal diameter (BPD), abdominal circumference (AC), head circumference (HC) and femur length (FL) on 122 singleton pregnancies. Patients were each examined twice by the first sonographer to determine the intraobserver reliability of measurements of fetal biometry. Subsequently, during the same ultrasound examination, a second blinded sonographer measured fetal biometric parameters to assess interobserver reliability. The consensus between and among observers was analyzed using the intraclass correlation coefficient (intra-CC) and interclass correlation coefficient (inter-CC) and the reliability coefficients (RC, alpha) for the four biometric measurements. A value > 0.75 was considered a reliable consensus for the intra-CC and inter-CC. A Bland and Altman plot was also created for the fetal biometric parameters to assess the repeatability of the measurements. RESULTS: Reliable consensus was observed for both the intra-CC and inter-CC and RC for all four biometric parameters. The intra-CC with the 95% CI and RC for the BPD, AC, HC and FL were as follows: 0.996 (0.995, 0.997), alpha 0.998; 0.994 (0.992, 0.996), alpha 0.997; 0.996 (0.994, 0.997), alpha 0.998; and 0.994 (0.992, 0.996), alpha 0.997, respectively. Similarly, the inter-CC with the 95% CI and RC for the same parameters were as follows: 0.995 (0.993, 0.997), alpha 0.998; 0.980 (0.971, 0.990), alpha 0.990; 0.994 (0.992, 0.996), alpha 0.997; and 0.990 (0.985,0.993), alpha 0.995, respectively. The Bland and Altman plots demonstrated a high degree of repeatability of BPD, AC, HC, and FL measurements. CONCLUSION: Our results demonstrate that the intra- and interobserver reproducibility of ultrasound measurements of fetal biometry are highly reliable.     

Fetal transabdominal biometry at 11-14 weeks of gestation.

OBJECTIVE: To establish comprehensive transabdominal ultrasonographic reference ranges for viable normal singleton human fetuses at 11-14 weeks' gestation. METHODS: Single transabdominal ultrasound measurements were taken once per pregnancy at a gestational age of between 11+0 and 14+0 weeks (crown-rump length, 45-84 mm), in viable singleton fetuses with nuchal translucency < or = 3 mm and without detectable structural anomalies, using four standard planes: (i) biparietal diameter (BPD) and fronto-occipital diameter (FOD) resulting in head circumference (HC), anterior horn (Va), posterior horn (Vp), and hemisphere (HEM); (ii) transcerebellar diameter (TCD) and cisterna magna (CM); (iii) abdominal anteroposterior (AAP) and abdominal transverse diameter (ATD) resulting in abdominal circumference (AC); and (iv) femur length (FL). The respective ratios Va/HEM, Vp/HEM, HC/AC, BPD/FL, BPD/FOD, FL/CRL, FL/BPD and FL/AC and the estimated weight were derived. Reference ranges were constructed and the mean and 5th and 95th centiles were plotted against gestation. RESULTS: There was a general increase in biometric parameters with gestation. The ratios for the ventricles vs. hemisphere and BPD/FL ratio decreased while the BPD/FOD and HC/AC ratios remained constant. Analysis of the reference range for BPD/FL was performed in both 167 and 664 fetuses and the results showed almost the identical type of equation, indicating a high degree of accuracy for the growth charts. CONCLUSIONS: We have established comprehensive reference ranges for first-trimester fetal biometry by transabdominal sonography. These charts may have a role in the diagnosis of early onset symmetrical or asymmetrical growth restriction and in the interpretation of measurements in chromosomally abnormal fetuses, and they may help in the detection of skeletal dysplasias or acrania/anencephaly.     

自动容积导航技术获得胎儿颅脑切面及自动测量参数的可靠性和准确性

目的 评价自动容积导航（Smart planes）技术快速获得胎儿颅脑重要切面的可靠性及其自动测量颅脑参数的准确性。方法 将80胎正常胎儿（正常组）和16胎颅脑发育异常胎儿（异常组）纳入研究,先采用二维超声以传统方法获得胎儿颅脑基本切面,包括丘脑切面（TTP）、侧脑室切面（TVP）、小脑横切面（TCP）和正中矢状面（MSP）,并手动测量双顶径（BPD）、头围（HC）、侧脑室宽度（LVW）、小脑横径（TCD）和小脑延髓池深度（CMD）;然后采用自动容积导航技术获取以上切面,并自动获得以上参数。对比两种方法测量各参数和用时的差异,分析两种方法测量的一致性。结果 正常组传统方法与自动容积导航技术获取TTP、TVP、TCP的成功率差异无统计学意义（P均=0.069）,异常组传统方法的成功率高于自动容积导航技术（P<0.001）;对获取MSP,正常组和异常组中自动容积导航技术的成功率均高于传统方法（P均<0.05）。2组中自动容积导航技术用时均小于传统方法（P均<0.001）。正常组中两种方法测量BPD、HC、TCD、LVW、CMD结果的组内相关系数分别为0.931、0.818、0.641、0.704和0.503,异常组分别为0.947、0.892、0.908、0.824和0.571。结论 自动容积导航技术操作简便、省时,对操作者技术依赖性小,与传统方法测量结果的一致性较高,对快速评价胎儿颅脑发育具有一定应用价值。     

超声经后脑横断面观察11~13+6孕周胎儿颅内后脑结构的研究

目的 探讨超声经后脑横断面观察11~13+6孕周胎儿颅内后脑结构的可行性，以期在开展对早中孕胎儿颅内结构进行有效筛查的同时缩短检查时间。方法 随机选择2695例11~13+6孕周正常胎儿进行颅脑正中矢状面及经后脑横断面切面的获取，观察后脑结构并分别测量颅内透明层的厚度进行统计比较两者一致性。结果 2695例胎儿中，2402例获得颅脑正中矢状切面及经后脑横断面，另有239例仅获得经后脑横断面，未获得颅脑正中矢状切面。颅脑正中矢状切面及经后脑横断面均可观察到胎儿后脑“二高三低回声带”结构，2402例胎儿两种切面所测IT值使用MedCalc医学统计软件进行Bland-Altman绘图分析。两种切面所测IT值具有较高的一致性。结论 经后脑横断面与颅脑正中矢状切面同样可以有效观察胎儿后脑结构，但经后脑横断面的获取较少受到胎儿体位限制，该切面的运用可提高超声医师的工作效率，同时对于体位不佳的胎儿，经后颅窝横断面为观察其颅脑结构提供一个有效的途径。     

不同初始切面胎儿心脏三维容积包成像在胎儿心脏超声检查中的价值

目的 研究不同初始切面胎儿心脏三维容积包图像质量,探讨三维成像技术联合断层超声显像技术在正常胎儿心脏超声检查中的价值.方法 应用胎儿三维成像技术对158例胎儿(孕16~40周)心脏以心尖四腔心切面和胸骨旁四腔心切面作初始切面采集三维容积数据.应用软件进行离机分析,用断层超声显像模式对胎儿四腔心、五腔心、三血管气管、左心室流出道、右心室流出道、大动脉短轴、主动脉弓、动脉导管弓、上下腔静脉长轴9个标准切面进行显示.按不同孕龄将158例胎儿分为3组,A组(16~24周)、B组(25~32周)和C组(33~40周),对3组胎儿9个标准切面显示情况进行组间对比分析.结果 应用心脏三维容积技术在158例胎儿中采集到满意的心脏容积数据包图像149个,其中心尖四腔心切面容积包72个,胸骨旁四腔心切面容积包77个.(1)上下腔静脉切面、大动脉短轴切面图像清晰显示率(2分切面率),心尖四腔心切面容积包图像及胸骨旁四腔心切面容积包图像的A组与B组间对比,差异均有统计学意义(心尖四腔心切面容积包χ2=4.927、22.938,胸骨旁四腔心切面容积包χ2=6.312、21.761,P均<0.05).(2)主动脉弓切面、动脉导管弓切面图像清晰显示率(2分切面率),仅在心尖四腔心切面容积包图像的A组与B组间对比差异有统计学意义(χ2=8.053、4.967,P均<0.05).(3)心尖四腔心切面容积包和胸骨旁四腔心切面容积包B组图像清晰显示率最高,C组其次,A组最低.结论 心尖四腔心切面和胸骨旁四腔心切面均可作为胎儿心脏三维容积成像采集初始切面,三维容积成像中重建切面受外部条件影响明显.胎儿心脏三维超声检查最佳孕龄范围为25~32孕周,孕龄大小对以心尖四腔心作初始切面的心脏三维图像质量影响较大.这两个初始切面可为胎儿心脏三维容积图像规范化采集和远程会诊图像规范化采集提供参考.     

应用三维超声检测孕11+2～14+2周胎儿颈部透明层厚度的可行性分析

目的：探讨利用三维超声技术获得标准正中矢状切面测量颈部透明层厚度的可行性,评价三维超声技术在此方面是否有优越性。方法：对198例孕11+2～14+2周的胎儿应用二维超声及三维超声分别测量胎儿颈部透明层厚度,对比二者测量值是否有统计学差异。结果：对198例检测结果进行统计学分析,结果显示三维超声测量NT值与二维超声测量NT值统计学上无显著性差异（t=0.488,P=0.626＞0.05）,二者之间具有可比性,二者测得的颈部透明层厚度均与孕周呈正相关,三维超声及二维超声测得颈部透明层厚度与孕周相关系数分别为r=0.536,P<0.05;r=0.543,P<0.05。结论：应用三维超声重建功能及三维扩展成像技术能够获得测量胎儿颈部透明层厚度所需的标准正中矢状切面,因此三维超声在检测胎儿颈部透明层厚度方面是可行的。     

中晚孕期胎儿胼胝体观察新方法：二维颅脑横切面法

目的确定二维超声颅脑横切面上胼胝体观测切面及建立20周至足月正常胎儿横切面上胼胝体各径线参考值。 方法选取2018年6月至2018年12月在南方医科大学附属深圳妇幼保健院行产前超声检查诊断无结构异常且因"计划外生育"或者母体宫颈机能不全在我院引产，其父母同意尸体解剖的10例20~30周单胎胎儿作为研究对象。采用三维自由解剖成像法和冰冻标本解剖法获取胼胝体的系列横切面/横断面。观察上述两种方法获取的系列横切/断面，总结各切面及对应断面的特征，得出横切面上胼胝体结构观察的稳定切面。选取同时期在南方医科大学附属深圳妇幼保健院常规产前超声检查无结构异常的670例孕20周至足月的单胎胎儿，在第一部分选定的胼胝体横切面进行胼胝体膝部前角、后角，压部前角、后角，胼胝体最大前后径，膝部左右径、前后径，压部左右径、前后径，体部前后径、左右径的测量。随机抽取40例胎儿行上述参数两测量者间的重复性检验；建立各孕周颅脑横切面上胼胝体各参数的正常参考值范围，绘制所测数据与孕周的散点图并行相关性分析，建立线性回归方程。 结果三维自由解剖成像法和冰冻标本解剖法所获胼胝体3个横切面恒定显示相同的解剖结构。两观察者之间的重复性检验未见明显差异。各散点图显示正常胎儿胼胝体各参数测值与孕周呈正相关（r=0.232、0.343、0.284、0.182、0.913、0.895、0.748、0.787、0.736、0.684、0.734，P均<0.01）。对各参数与孕周进行回归分析，回归方程分别为：Y=0.514X＋52.214，Y=0.785X＋42.897，Y=0.600X＋47.327，Y=0.436X＋53.056，Y=0.117X＋0.019，Y=0.070X-0.169，Y＝0.013X＋0.054，Y=0.065X＋0.180，Y=0.014X＋0.064，Y=0.047X＋0.547，Y=0.027X-0.116。 结论基于三维自由解剖成像和冰冻标本解剖确定的系列切面相对固定，可作为胼胝体结构评估的切面。不同孕周胎儿胼胝体各径线正常参考值可作为产前评估胼胝体发育异常的参考依据。     

产前超声于左无名静脉切面测量孕20~38周胎儿胸腺参数

目的 观察产前超声于左无名静脉切面测量孕20~38周胎儿胸腺参数的价值。方法 前瞻性纳入661名孕20~38周健康单胎妊娠孕妇,采用超声分别于三血管切面和左无名静脉切面测量胎儿胸腺参数,包括胸腺横径、前后径、周长及横断面积,分析各参数与孕周的相关性,观察并对比于两切面测量胸腺参数的价值。结果 超声于三血管切面所测孕35~38周胎儿胸腺横径及孕20~38周胎儿胸腺前后径、周长和横断面积均小于左无名静脉切面（P均<0.05）;且相同切面所测胎儿胸腺参数均随孕周增长而增高（P均<0.05）。三血管切面（r=0.873、0.793、0.839、0.858,P均<0.001）和左无名静脉切面（r=0.901、0.796、0.866、0.904,P均<0.001）胸腺横径、前后径、周长及横断面积测值均与孕周呈正相关。观察者间及观察者内测量胸腺参数的一致性均好（ICC均>0.75,P均<0.001）,于左无名静脉切面测量的ICC略高。结论 产前超声于左无名静脉切面测量孕20~38周胎儿胸腺各参数可减小测量误差,在一定程度上弥补三血管切面测量的不足。     

Does the Use of Automated Fetal Biometry Improve Clinical Work Flow Efficiency?

This study was designed to compare the work flow efficiency of manual measurements of 5 fetal parameters with a novel technique that automatically measures these parameters from 2‐dimensional sonograms. This prospective study included 200 singleton pregnancies between 15 and 40 weeks' gestation. Patients were randomly allocated to either manual (n = 100) or automatic (n = 100) fetal biometry. The automatic measurement was performed using a commercially available software application. A digital video recorder captured all on‐screen activity associated with the sonographic examination. The examination time and number of steps required to obtain fetal measurements were compared between manual and automatic methods. The mean time required to obtain the biometric measurements was significantly shorter using the automated technique than the manual approach (P < .001 for all comparisons). Similarly, the mean number of steps required to perform these measurements was significantly fewer with automatic measurements compared to the manual technique (P < .001). In summary, automated biometry reduced the examination time required for standard fetal measurements. This approach may improve work flow efficiency in busy obstetric sonography practices.     

新型智能产前超声技术SFA自动识别与获取胎儿标准切面

目的 观察新型智能产前超声技术SFA自动识别与获取胎儿标准切面的临床价值。方法 分别以传统超声和SFA技术识别并获取1 127胎≥16孕周单胎胎儿的标准切面,比较获取图像成功率(实际获取图像数/应获取图像数×100%)和图像合格率(合格图像数/实际获取图像数×100%),以及获取不同孕周胎儿标准切面所用时间。结果 SFA获取胎儿经丘脑横切面、经侧脑室横切面、四腔心切面、脐带腹壁入口切面、双肾水平横切面的成功率均低于传统超声(P均<0.05),获取经侧脑室横切面、四腔心切面、腹围横切面的合格率均高于传统超声,获取膀胱水平横切面合格率低于传统超声(P均<0.05)。对不同胎龄胎儿,SFA获取标准切面所用时间均少于传统超声(P均<0.05)。结论 SFA技术获取胎儿标准切面具有一定临床价值,且用时少于传统超声。     

Evaluation of early third-trimester ultrasound screening for intrauterine growth retardation

Ultrasound fetal biometry is widely used for detection of intrauterine growth retardation (IUGR). Since fetal growth is a dynamic process, studies estimating validity of ultrasound near term may not be applicable earlier in pregnancy. This study applied receiver operating characteristic (ROC) curve analysis to ultrasound biometric data obtained at 26-34 weeks gestation to predict fetuses destined to be IUGR at birth. In this method, the area under the curve (theta) is the index of performance. Sixty-nine (9%) of the 768 singleton infants studied were IUGR at birth. Ultrasound estimated fetal weight (theta = .793) and abdominal circumference (theta = .785) had equivalent performance, significantly better than head circumference (theta = .724) or femur length/abdominal circumference ratio (theta = .619). Performance was not as good as suggested by studies conducted within 2 weeks of delivery.     

Computer assisted analysis of fetal age in the third trimester using multiple fetal growth parameters

A new technique is described for predicting menstrual age in the third trimester of pregnancy (28-42 weeks) using multiple fetal growth parameters (biparietal diameter, head circumference, abdominal circumference, femur length). Evaluation of this technique in 177 normal third trimester pregnancies demonstrated that significant improvement in the variability in predicting menstrual age can be achieved when two or more parameters are used collectively instead of a single parameter used individually. The optimal combination prior to 36 weeks was biparietal diameter, abdominal circumference, and femur length, while after 36 weeks the optimal combination was head circumference, abdominal circumference, and femur length. The use of these combinations resulted in smaller mean errors, standard deviations, and maximum errors. Regression equations and tables of normal values are provided to facilitate the use of this dating method.     

孕11~13+6周胎儿后脑结构经后脑横断面的超声观察

目的探讨超声经后脑横断面观察孕11~13+6周胎儿后脑结构的可行性。方法随机选择2695例孕11~13+6周胎儿,行颅脑正中矢状面及经后脑横断面超声检查,观察后脑结构并测量后脑透明层厚度;分析两切面检测颅内透明层厚度的一致性。结果 2695例胎儿中,2402例均获得颅脑正中矢状切面及经后脑横断面(其中1例两切面后脑结构均显示异常),239例仅获得经后脑横断面,54例未获得两切面。正常胎儿后脑在颅脑正中矢状切面及经后脑横断面均显示为"二高三低回声带"结构。两切面所测的胎儿透明层厚度一致性较好(一致性偏倚为0.0219,一致性界限为-0.2740~0.2874)。结论孕11~13+6周经后脑横断面观察胎儿后脑结构可作为一种安全、快速、有效的方法筛查胎儿神经系统畸形。     

Abdominal circumference: a single measurement versus growth rate in the prediction of intrapartum Cesarean section for fetal distress.

OBJECTIVE: The fetal abdominal circumference is the most sensitive ultrasound biometric measurement for predicting intrauterine growth restriction, which is associated with an increased risk of intrapartum fetal distress. We sought to evaluate and compare whether a third-trimester ultrasound measurement of abdominal circumference made within 1 week prior to delivery better predicts operative delivery for fetal distress when compared with the growth velocity of the abdominal circumference in the third trimester. METHODS: Retrospective analysis was carried out of prospectively collected ultrasound data on 117 patients with singleton gestations who had had at least two ultrasound assessments performed less than 6 weeks apart in the third trimester, with the last ultrasound performed within 1 week prior to delivery. The abdominal circumference value of the last ultrasound prior to delivery was placed into one of three categories: < or = 5% centile, > 5 to < or = 10% centile and > 10% centile for gestational age. The growth velocity of the abdominal circumference per week was placed into one of three categories: < or = 5 mm/week, 6-10 mm/week and > or = 11 mm/week. The chi-squared test was used to compare differences between the incidence of fetal distress between the groups. RESULTS: The incidences of Cesarean section for fetal distress in relation to a single measurement of the abdominal circumference were: < or = 5% centile, 8/23 (35%); > 5 to < or = 10% centile, 3/12 (25%); > 10% centile, 8/81 (10%) ( P < 0.05). The incidences of Cesarean section for fetal distress with the three abdominal circumference growth velocities were: < or = 5 mm/week, 9/55 (16%); 6-10 mm/week, 4/11 (36%); > or = 11 mm/week, 8/51 (16%) ( P = 0.9401). CONCLUSION: A single measure of the fetal abdominal circumference made within 1 week prior to delivery is superior to an assessment of growth rate of the fetal abdomen in the third trimester in discriminating patients who require Cesarean section for fetal distress.     

A comparison of fetal biometric ratios to neonatal morphometrics

Ratios of fetal abdominal circumference to femur length (AC/FL) and thigh circumference to femur length (TC/FL) have been suggested as indices of fetal nutrition. Birthweight, skin-fold thickness, and ponderal index are accepted neonatal indices of nutrition. The purpose of this study was to compare fetal to neonatal indices of nutrition. In 52 patients in term labor, fetal abdominal circumference, thigh circumference, and femur length were measured ultrasonographically. Neonatal skin-fold thickness was calculated as the average of tricipital, subscapular, abdominal, and anterior thigh measurements determined with Harpenden skin-fold calipers. Linear correlation analysis demonstrated a significant relationship between AC/FL and ponderal index (r = 0.340, P = 0.028) and between TC/FL and ponderal index (r = 0.368, P = 0.007). Neither AC/FL nor TC/FL were significantly related to birthweight or skin-fold thickness. These data suggest that the diagnostic reliability of antenatal studies of fetal biometric ratios may be enhanced by using the ponderal index as a neonatal endpoint rather than birthweight or skin-fold thickness.