Prediction of birthweight by fetal ultrasound biometry.

A total of 104 women with singleton pregnancies who were delivered between 37 and 42 weeks gestation had ultrasound scans during the fortnight before delivery. The biparietal diameter (BPD), abdominal circumference (AC) and femur length (FL) were measured in all cases. Estimation of fetal weight (EFW) was done by four different methods: using AC alone, AC/BPD, AC/FL and AC/BPD/FL. Results were compared with values of actual birthweights at delivery. There was no significant difference between the mean birthweights of the 47 boy and 57 girl fetuses studied. The EFW(Shepard) method showed the least bias overall: mean percentage error 1.7%, standard deviation (SD) 10.6%. The other three methods significantly underestimated birthweights on average: EFW(Deter), mean error 2.2%, SD 9.3%, p < 0.02; EFW(Campbell), mean error 5.4%, SD 9.5%, p < 0.001; EFW(Hadlock), mean error 5.6%, SD 9.3%, p < 0.001. The percentage error in each group was significantly negatively correlated (p < 0.001) with the scan-delivery interval. Two new equations were generated which gave more accurate predictions for the cases under study using AC, BPD and FL as a combination and also in addition to scan-delivery interval (SDI) in days.     

Ultrasonic fetal size measurements in Brisbane, Australia

The purpose of this paper was to construct population-specific charts of fetal biometry for 11-41 weeks gestation in relation to known gestational age from a large population of normal Australian pregnancies when examination is performed to a standard protocol by experienced operators. All consenting eligible women attending a large Brisbane clinic between January 1993 and April 2003 were recruited. Menstrual history was taken prior to examination. Measurements were performed to a standard protocol. Prospective assessment was made about the association between gestational age from the last menstrual period and biometry. Exclusion principles were applied. Statistical analyses were performed using polynomial regression models and thorough diagnostic checks were undertaken. Included within the study were separate scans for 20 555 pregnancies from 17 660 women. Equations, means and 95th reference intervals were derived and reported for the following sonographic measurements: biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL). Population-specific regression equations for BPD, HC, AC and FL have been proposed for Australian pregnancies. Once validated by others, we believe they will warrant consideration for adoption by the Australasian Society for Ultrasound in Medicine.     

B型超声对妊娠胎儿体重预测的研究

目的为了提高B型超声预测胎儿体重的准确性。材料与方法对262例在分娩前5天内,用B型超声测定胎儿双顶径、腹围、肝脏长度、股骨长度,分别用各种方程式得出胎儿体重,并与新生儿实际出生体重进行比较。结果单项腹围预测胎儿体重与新生儿实际体重的相关性最好。结论应用B型超声测量胎儿腹围预测胎儿体重的方法简便、准确,有较好的临床应用价值。     

Three-dimensional US of the fetus: volume imaging

PURPOSE: To retrospectively compare the rapidity, efficiency, and accuracy of three-dimensional (3D) and two-dimensional (2D) ultrasonography (US) for complete anatomic survey in fetuses at 17-21 weeks of gestation. MATERIALS AND METHODS: Institutional review board approval was obtained, informed consent was waived, and the study was HIPAA compliant. Fifty consecutive women undergoing fetal anatomic survey at 17-21 weeks of gestation formed the study cohort. After standard 2D US was performed by one of eight sonographers, the same sonographer also obtained five 3D volumes to encompass the entire fetal anatomy. Three physicians interpreting the scans independently evaluated the completeness of the examination and time needed to read the scans, comparing the standard 2D method with the 3D volume reconstruction technique. The paired t test was used to compare biparietal diameter (BPD), femur length, and performance times between the 3D measurements and the 2D measurement. The t test was used to compare fetal anatomy according to volume angle. Differences were significant when P < .05. RESULTS: Mean time to perform 2D US was 19.6 minutes per examination, whereas mean time to perform complete 3D volume acquisition was 1.8 minutes. Mean times needed to interpret 3D images and measure the BPD and femur were 5.53, 4.79, and 5.34 minutes for the three interpreting physicians. Compared with complete fetal surveys performed with 2D US, individual fetal anatomic landmarks (except for fetal arms and cavum septum pellucidum) were identified more than 94% of the time by using 3D US. Grouping anatomic views by region, the heart, head, extremities, and abdominal views were completely seen in 88%, 90%, 90%, and 95% of patients, respectively. No significant difference was seen between the three physicians regarding completeness of the 3D examinations (P = .7). One fetus had multiple anomalies, with 3D volumes identified as abnormal by all three physicians. Overall, 74% of 3D BPD measurements were within 1 mm of the 2D measurements, and 64% of 3D femur measurements were within 1 mm of the 2D measurements. CONCLUSION: The standard fetal anatomic survey can be performed in less than 2 minutes with 3D volume US, and the volumes can be interpreted in 6-7 minutes, compared with a mean of 19.6 minutes to perform standard 2D US.     

Morphology and growth of the fetal stomach.

To assess the development of the fetal stomach, we performed 162 esophageal injections of contrast media into spontaneously aborted normal fetuses from 7.5 to 26 weeks of gestation. The length of esophagus and trunk, greater and lesser curvature, and vertical and oblique axis of stomach were measured, and the means and standard deviations at each gestational age were calculated. The most frequently encountered patterns of stomach shape were: the standard shape, 90%; steerhorn, 3%; and horizontal stomach, 2%. The final shape of the stomach is not assumed at least until the the age of 22 weeks. Regarding the growth of stomach, with age, the greater curvature grew at a much faster rate than the lesser curvature, and the distance between skin and outer border of the stomach increased. The oblique axis of the stomach did not rotate after eight weeks; gastric surface area showed the fastest growth after 14 weeks. The gastroesophageal junction cephalad relative to the trunk ascended through week 25, due to the differential growth of the trunk and esophagus.     

Growth of the fetal kidney. Echographic study

An echographic study of the fetal normal kidney in 274 fetuses (548 kidneys measured) from 15 to 40 weeks of pregnancy is proposed by the authors. This work includes morphologic and biometric study with the growth curves of 4 parameters. It is shown that both kidneys are morphologically similar and their growth is continuous and there is a constant ratio between the different parameters. Ratios are established: Length/BPD = 0,45 +/- 10%, Width/BPD = 0,27 +/- 10%, Thickness/BPD = 0,26 +/- 10% which are very useful for the echographist. One hopes that with morphologic and biometric criteria of normality, the early detection of urinary tract malformations will be easier.     

Delayed interval delivery military style

INTRODUCTION: Intentionally delaying the delivery of a second twin from a previable state to a gestational age when survival is possible is a heroic measure whose outcome is unpredictable. We report the case of delayed interval delivery in a patient transported via air evacuation to a tertiary care center. CASE REPORT: A 31-year-old gravida 3 para 0020 at 18 weeks with a twin gestation presented to a medical treatment facility for evaluation of uterine cramps. She subsequently delivered Twin A. With cessation of labor, the patient was air evacuated to a medical center for continued care. Seven weeks later, she delivered a viable male infant. DISCUSSION: The treatment of multiple gestations presenting with preterm labor or rupture of membranes remains expectant. When delayed delivery of a previable second twin is undertaken, appropriate care includes the use of antibiotics, tocolytics, and cervical cerclage. Anticipation of preterm birth warrants continued care in a tertiary care center offering neonatal intensive care.     

Use of furosemide in pregnancies complicated by oligohydramnios

To differentiate pregnancies complicated by oligohydramnios due to intrauterine growth retardation from those due to renal agenesis, the authors administered furosemide intravenously to eight pregnant women (19-25 weeks gestation) with oligohydramnios. The fetal abdomen was scanned with ultrasound to demonstrate the fetal urinary bladder. In six fetuses, sonography failed to demonstrate the bladder: two fetuses had growth retardation with normal kidneys and bladder, and four had renal anomalies. It is concluded that administration of furosemide to the mother fails to induce diuresis in growth-retarded fetuses of 19-23 weeks gestation and that failure to see the fetal bladder after furosemide administration does not necessarily indicate absent fetal kidneys.     

胎儿肝脏MRI信号强度的意义

目的：探讨宫内胎儿肝脏的生长发育状况。材料和方法：采用超导0．35T磁共振成像仪，对44例中、晚孕程孕妇进行MR成像，观察、分析其中42例正常胎儿肝脏的形态结构、信号变化。结果：胎肝的形态、大小以及肝内的门静脉、肝静脉等被良好显示。在T1WI上，孕32周前，胎儿肝脏的信号呈不均匀的高信号；在孕32周后，胎儿肝脏的信号呈均匀的一致的中等信号。在PDWI及T2WI上，胎儿肝脏的信号在不同的孕周均呈等信号。结论：MRI对胎肝的生长发育状态的研究有重要价值，胎肝在T1WI上均匀一致和中等信号（约孕32周后）代表着胎肝的发育成熟；而PDWI及T2WI对揭示胎肝的发育成熟不敏感。     

Prenatal magnetic resonance imaging: brain normal linear biometric values below 24 gestational weeks

Introduction  Prenatal magnetic resonance (MR) imaging is currently used to measure quantitative data concerning brain structural development. At present, morphometric MR imaging studies have been focused mostly on the third trimester of gestational age. However, in many countries, because of legal restriction on abortion timing, the majority of MR imaging fetal examination has to be carried out during the last part of the second trimester of pregnancy (i.e., before the 24th week of gestation). Accurate and reliable normative data of the brain between 20 and 24 weeks of gestation is not available. This report provides easy and practical parametric support to assess those normative data. Materials and methods  From a database of 1,200 fetal MR imaging studies, we retrospectively selected 84 studies of the brain of fetuses aged 20–24 weeks of gestation that resulted normal on clinical and radiological follow-up. Fetuses with proved or suspected infections, twin pregnancy, and fetuses of mothers affected by pathology that might have influenced fetal growth were excluded. Linear biometrical measurements of the main cerebral structures were obtained by three experienced pediatric neuroradiologists. Results  A substantial interobserver agreement for each measurements was reached, and normative data with median, maximum, and minimum value were obtained for brain structures. Conclusion  The knowledge of a range of normality and interindividual variability of linear biometrical values for the developing brain between 20th and 24th weeks of gestation may be valuable in assessing normal brain development in clinical settings.     

胎儿先天性肢体畸形的MRI诊断探讨

目的 探讨MRI在胎儿先灭性肢体畸形诊断中的应用价值.方法 回顾性分析胎儿先天性肢体畸形的MRI表现.16例孕妇年龄22～40岁,平均29岁;孕龄22～39周,平均29周.产前常规行超卢(US)检查后24～48 h内行MR检查,采用二维快速稳态自由进动序列(2D FIESTA),行胎儿颅脑脊柱胸腹部常规及肢体重点扫描,将产前MRI、US表现与出牛后影像表现或外观(4例胎儿)、引产后尸体解剖或外观检查结果 (12例孕妇共13例胎儿,其中1例孕妇为双胎)对照.结果 16例孕妇共检出胎儿17例.包括先天性双上肢完全截肢1例,人体鱼序列征1例,短肢畸彤6例,双手腕内翻畸形2例,右手多指畸形1例,单纯有手缺指畸形1例,右手截指畸形1例,单纯马蹄内翻足2例,脊柱裂脑积水伴马蹄内翻足2例(其中1例还伴双手叠指样屈曲).16例孕妇随访结果 与产前MRI诊断完全一致14例,不完全一致2例.结论 MRI在胎儿先天性肢体畸形诊断方面具有一定的应用价值,能提供超声以外的额外信息,甚至更正超声的诊断.     

Fetal intracranial anatomy in the first trimester of pregnancy: transvaginal ultrasonographic evaluation

Summary The normal values and ranges of fetal intracranial structures were studied by high resolution transvaginal ultrasonic scan at 12, 13 and at 14 weeks' gestation. The data including measurements of crown rump length (CRL), bi-parietal diameter (BPD), head circumference (HC), hemispheric width (HW), lateral ventricle width (LVW), LVW/HW ratio, thalamus and cerebellum may be useful in determining deviations from the normal and also in expanding the range of prenatal diagnoses of fetal structural abnormalities in early pregnancy.     

Ultrasound prediction of fetal lung maturity

Amniocentesis for determination of fetal lung maturity and ultrasonographic (US) evaluation of the biparietal diameter (BPD) and placental grade were performed simultaneously in 261 nondiabetic pregnant women. A BPD of at least 9.3 cm and a grade 3 placenta were evaluated as predictors of fetal lung maturity using amniotic fluid phospholipids as indicators of a mature lung profile. The ability of the sonographic parameters to predict fetal lung maturity was closely related to menstrual age. Before 37 weeks, the false-positive prediction rate using a grade 3 placenta was 100%, and the false-positive prediction using the BPD was 85.6%. After 37 weeks, the false-positive rate using a grade 3 placenta was 5.9%, and the false-positive rate using the BPD was 9.5%. Thus menstrual age, and not these two US parameters, dictated fetal lung maturity. The authors conclude that the best use of US for predicting fetal lung maturity is in establishing menstrual age early in pregnancy.     

胎儿先天性肺囊腺瘤样畸形的MRI诊断与鉴别诊断

目的:探讨MRI在胎儿先天性肺囊腺瘤样畸形(CCAM)诊断与鉴别诊断中的应用价值.方法:36例孕妇,年龄21～38岁,平均29岁;孕龄20～31周,平均24周.产前常规行超声(US)检查后24～48h内行MR检查,采用二维快速平衡稳态采集 (2D-FIESTA) 序列、单次激发快速自旋回波(SSFSE)序列,行胎儿颅脑...     

胎儿神经管缺陷畸形的MRI诊断

目的 探讨MRI在胎儿神经管缺陷畸形诊断中的应用价值.方法 回顾性分析行MR检查的629例异常胎儿中10例神经管缺陷畸形胎儿的MRI资料.10例孕妇产前超声检查后24～48 h内行MR检查,采用2D快速平衡稳态采集序列、单次激发FSE序列以及快速反转恢复运动抑制序列,行胎儿颅脑、胸、腹部常规及颅脑、脊柱重点冠状面、矢状面及横断面扫描,将产前MRI、超声表现与出生后脊髓MRI(3例)、引产后尸体外观检查或尸体解剖结果(7例)对照.结果 9例为单胎,1例为双胎之一.随访结果与产前MRI诊断完全一致,产前超声漏诊1例、误诊2例.10例胎儿中无脑畸形1例,露脑畸形1例,羊膜带综合征所致脑膜脑膨出1例,脑膜膨出1例,胸段脊髓脊膜膨出1例,腰段脊柱裂1例,骶尾部脊髓脊膜膨出2例,骶尾部巨大囊状脊膜膨出1例,骶尾部脊柱裂1例.结论 MRI在胎儿神经管缺陷畸形诊断方面具有较高的应用价值,能准确鉴别膨出内容物、定位脊髓病变位置.     

Normal and hypoplastic fetal lungs: volumetric assessment with prenatal single-shot rapid acquisition with relaxation enhancement MR imaging

PURPOSE: To determine which parameters are most closely correlated with normal fetal total lung volume and to investigate the use of these parameters in the evaluation of fetal pulmonary hypoplasia. MATERIALS AND METHODS: Single-shot rapid acquisition with relaxation enhancement (RARE) magnetic resonance (MR) imaging was used to perform planimetric measurement of total lung volume in 46 fetuses at 18-32 weeks gestation. Total lung volume was correlated with gestational age, and biometric parameters in fetuses were correlated with normal chest findings at ultrasonography (US) (n = 24). This analysis was used to evaluate relative lung volume in fetuses suspected of having pulmonary hypoplasia (n = 22). RESULTS: Normal fetal total lung volume was strongly correlated with liver volume measured at MR imaging (r = 0.94), fetal weight estimated at US (r = 0.93), head circumference measured at US (r = 0.90), and gestational age (r = 0.87). In fetuses suspected of having pulmonary hypoplasia, the relative lung volume varied from 4.6% to 81.6% when the observed total lung volume was expressed as a percentage of the predicted total lung volume. CONCLUSION: Normal fetal total lung volume is strongly correlated with biometric measurements. Relative fetal lung volume can be calculated by expressing the observed volume as a percentage of the predicted volume calculated from biometric measurements; knowledge of the relative fetal lung volume assists in the confirmation and quantification of fetal pulmonary hypoplasia.     

MRI对胎儿胼胝体缺如的诊断价值

目的 探讨MRI对胎儿胼胝体缺如的诊断价值. 资料与方法 超声（US）怀疑胎儿胼胝体缺如的孕妇9例,平均年龄25岁（18～29岁）,平均孕周32周（28～36周）,所有患者均在US检查后2天内行MRI检查.将US、MRI结果与出生后或引产后结果对照. 结果 MRI与US比较,胎儿胼胝体缺如基本一致者3例;US可疑、MRI肯定者6例,其中出生后随访证实者2例,引产后证实者4例;对于其伴发畸形,两者基本一致者5例,MRI多于US者4例. 结论 MRI对胎儿胼胝体缺如有较高的诊断价值,可作为US有利的补充及验证手段.     

Twin reversed arterial perfusion (TRAP) sequence: A case report and a brief literature review

Twin reversed arterial perfusion (TRAP) sequence is rare in monochorionic twin pregnancies. TRAP sequence is distinct from other multifetal pregnancies in that one of the twins has normal anatomy while the other twin has a varied amount of characteristic abnormal features. In the literature, mortality is reported 100% in the abnormal twin. We report 1 case of TRAP sequence at our institution in which the diagnosis of TRAP sequence was missed in the first trimester at another hospital. The patient, a 33-year-old G1P0A0, did not have any follow-up after her first scan until the routine second-trimester ultrasound at our institution. Both the radiologist and the sonographer did not appreciate the differential diagnosis of TRAP sequence in their clinical decision-making. The TRAP diagnosis was established after the ultrasound performed at the fetal assessment unit in our hospital. Radiofrequency ablation (RFA) procedure was performed to give the normal twin a chance to survive, but unfortunately, the prognosis was poor in this case. We conclude that diagnosing a TRAP sequence is very important early in the pregnancy for a positive outcome in the normal twin. A robust collaboration among radiologists and obstetricians is vital for the best outcome of the normal twin.     

Use of ultrasonography to estimate fetal weight in premature infants. Development of a new mathematical formula

In 73 pregnant patients at a gestational age under 36 weeks, who gave birth within 72 hours from the last US examination, mathematical equations were elaborated. The equations were aimed at predicting fetal weight by measuring the main US biometric parameters; the results were compared to the actual birth weight. A statistical analysis was performed using the "backward elimination" method. The linear equation that has provided with the best estimation of fetal weight is the following: fetal weight = 12.9875 BPD +29.5642 AD +28.8023 FL -3496.1265. According to this equation, about 95.22% of the variability of the unknown quantity (i.e. birth weight) can be ascribed to its correlation to the variables: biparietal diameter (BPD), abdominal diameter (AD) and femur length (FL). Estimated fetal weight by US, as calculated on the basis of biparietal diameter, abdominal diameter and femur length measurements, showed, in our study, a standard error of 143 g (9.02%) (R = 0.95).     

胎儿肝脏血管内皮瘤MRI诊断的初步探讨

目的:探讨胎儿肝脏血管内皮瘤的产前MRI表现及诊断价值.方法:5例孕妇,孕龄22～ 37周.产前常规行超声(US)检查后24 ～ 48h内行MR检查,采用二维快速平衡稳态采集(2D FIESTA)序列、单次激发快速自旋回波(SSFSE)序列以及快速翻转恢复运动抑制(FIRM)序列,行胎儿颅脑胸腹部常规及肝脏重点冠状面、矢状面及横断面扫描,将产前MRI、US表现与出生后影像表现或手术病理结果对照.结果:5例肝脏血管内皮瘤均表现为肝脏内边界清晰的单个肿块,其中1例合并皮下多发血管瘤.在FIESTA、SSFSE序列上表现为不均匀稍高信号,在FIRM序列上表现为不均匀低信号.所有病例FIESTA序列肝脏横断面可见包块周边扩张的肝血管和远端腹主动脉变细.结论:产前MRI能提供诊断胎儿肝脏血管内皮瘤的有用信息,能提供产前US以外的补充诊断信息.