Prenatal interventions for fetal lung lesions

The widespread availability of high resolution ultrasound equipment and almost universal routine anatomy scanning in all pregnant women in the developed world has lead to increased detection of abnormalities in the fetal thorax. Already in the 1980s, large pleural effusions and significant macrocystic lesions in the fetus were easily detected on ultrasound. However, smaller lung tumours were often missed. Nowadays, fetal medicine centres receive many referrals for evaluation of fetal lung lesions, of which the most common are congenital cystic adenomatoid malformation and bronchopulmonary sequestration. Almost invariably, both the parents and the referring physicians experience anxiety after detection of large lung masses in the fetus. However, the vast majority of the currently detected fetal lung lesions have an excellent prognosis without the need for prenatal intervention. In the small group of fetuses in which the prognosis is poor, almost exclusively those with concomitant fetal hydrops and cardiac failure, several options for fetal therapy exist, often with a more than 50% survival rate. Indications, techniques, complications and outcomes of these interventions will be described in this review.     

Ultrasound and fetal diagnosis of perinatal infection

Prenatal ultrasound can aid the clinician in evaluation of the patient with a suspected in utero TORCH infection, particularly toxoplasmosis, syphilis, and CMV. Demonstration of characteristic ultrasound findings in the high risk patient has a high predictive value for fetal infection and also may have prognostic significance. The sonologist should understand the limitations of ultrasound, discuss them with the patient, and document the discussion in the medical record. Patients should be counseled that ultrasound is not a sensitive test for fetal infection and that a normal fetal anatomy survey cannot predict a favorable outcome. In the low-risk patient, fetal infection should be considered when multiple organ system anomalies, fetal growth restriction, placental enlargement, or abnormalities of amniotic fluid volume are demonstrated.     

Utility of a screening examination of the fetal cardiac position and four chambers during obstetric sonography

The findings were reviewed for approximately 6,700 high- and low-risk obstetric sonograms that included screening imaging of the fetal cardiac position and four chambers as part of a brief fetal anatomy survey. This screening examination identified 12 major cardiac malformations, 3 unusual cardiomegalies and 12 abnormal positions caused by noncardiac abnormalities. Most of these abnormalities probably would not have been identified without the screening examination. Also, the finding of an abnormal fetal cardiac position was often the main indication of a noncardiac abnormality, such as a diaphragmatic hernia. Screening imaging of the fetal cardiac position and four chambers appears to be a productive addition to the fetal anatomy survey for our particular mix of high- and low-risk patients.     

Transvaginal sonographic detection of embryonic-fetal abnormalities in early pregnancy

OBJECTIVE: To estimate the detection rate of abnormalities by transvaginal ultrasound in early pregnancy. METHODS: We prospectively analyzed records of 3592 sequential pregnant women at 10-16 weeks' (singleton) gestation (mean 13 weeks and 2 days). After exclusion of 114 women, there were 3478 women in the study. Each woman underwent a transvaginal sonographic survey for fetal anomalies as well as biometric measurements. Fetuses diagnosed with malformations were followed to delivery, and those without underwent transabdominal sonography at 18-24 weeks' gestation.Results: The anomaly detection rate by transvaginal ultrasound was 51.6% (33 of 64; 95% confidence interval [CI] 38.7, 64.2) in early pregnancy, and the detection rate by transvaginal ultrasound combined with second-trimester transabdominal ultrasound was 84.4% (54 of 64; 95% CI 73.1, 92.2). Cystic hygroma and fetal hydrops were the anomalies detected most frequently by transvaginal ultrasound. Low detection rates for abnormalities of the face and of the cardiac, skeletal, and urinary systems were found even when both methods were used. CONCLUSION: Transvaginal sonography appears to be an effective way to identify many congenital fetal anomalies in early pregnancy. There is a good probability of diagnosing cystic hygroma and fetal hydrops, although other abnormalities, particularly heart defects, are associated with lower detection rates.     

Fetal heart scanning in the first trimester

The detailed study of the fetal cardiac anatomy in the first trimester of pregnancy by means of ultrasound, transvaginally or transabdominally, is feasible and remains a safe procedure provided thermal and mechanical indices are taken into account. Optimal time for successful imaging of the four chambers and great arteries in early gestation appears to be between 13 to 14 weeks. In experienced hands, first-trimester fetal echocardiography is accurate in detecting major structural cardiac abnormalities and yields a high negative predictive value. Thus, in a clinical setting, it can be offered to families considered to be 'at risk' of cardiac defects (e.g. those with previous family history or when fetal nuchal translucency is increased) and can be a powerful tool to reassure families regarding normality of major cardiac structures and connections. However, the early detection of an important structural abnormality (chromosomally normal or not) may be associated with a high termination rate if this is an acceptable option. The high prevalence of associated chromosomal and extracardiac abnormalities for many of the high-risk families, who may benefit from this approach, cannot be ignored. Therefore, fetal heart scanning in the first trimester should be performed in conjunction with detailed first-trimester obstetric scanning.     

Two-dimensional echocardiographic assessment of normal fetal cardiac anatomy

The fetal heart is visualized routinely during the antepartum ultrasound examination. Because of the advent of high-resolution, real-time ultrasound instruments, details of fetal cardiac anatomy can now be defined. Fifty consecutive fetuses were examined in utero to assess the ability of two-dimensional echocardiography to define intracardiac anatomy at various gestational ages. A complete examination required at least three standard echocardiographic views of the heart: four-chamber, short-axis and long-axis views. In 30 of the 50 fetuses studied (60%) only one examination was necessary to obtain this information. Ten patients had a second examination later in gestation that complemented the findings of their first study. In all but two fetuses, detection of all four cardiac chambers and at least one semilunar valve was possible. Mitral-semilunar valve continuity was detected in all. The quality of echocardiographic imaging was enhanced by the fetal occiput posterior position (three views obtained in 83% of the fetuses studied). Breech position did not affect imaging quality. Prior to 30 weeks of gestation, fetal movement hampered analysis of fetal cardiac anatomy in some patients.     

Early detection of congenital heart disease in prenatal life

The anatomy of the fetal heart can be well seen by real-time cross sectional ultrasonography between 16 weeks' gestation and term. Many major structural abnormalities can be excluded in early pregnancy even if only one section of the fetal heart is studied. We have accurately predicted structural cardiac malformation in nine cases in the mid-trimester of pregnancy. Five pregnancies were interrupted for extracardiac abnormalities. In two cases of severe cardiac abnormality termination of pregnancy was chosen by the parents. In the remaining pregnancies where an abnormality was predicted delivery took place in a centre equipped for immediate care of an affected infant. This gave the infant the optimum chance of survival.     

Modern 3D/4D sonographic studies on fetal heart

We present herein modern three-dimensional (3D)/four-dimensional (4D) sonographic studies on fetal heart using 4D or real-time 3D fetal echocardiography, 3D/4D color/power Doppler ultrasound and 3D/4D high definition (HD)-flow, 3D/4D B-flow, and 3D/4D inversion mode. 3D/4D ultrasound provides a novel means for evaluation of fetal heart in 3D in real time, and of fetal intracardiac hemodynamics in the second and third trimesters. These novel techniques may assist in the evaluation of fetal cardiac anatomy and hemodynamics, and offer the potential advantages relative to conventional two-dimensional fetal echocardiography and Doppler flow mapping. 3D/4D ultrasound may be an important modality in future fetal cardiac research and in evaluation of congenital heart disease in the fetus.     

超声检查在胎儿监测中的应用

通过产前系统的超声筛查,使大约80%的胎儿畸形在产前得以诊断;同时,可了解胎儿宫内生长发育状况,为适时正确临床干预提供基础;另外,能及时发现胎儿附属物异常,并帮助判断胎儿宫内安危等。超声技术通过提供准确的胎儿宫内信息,明显提高了围产监护质量。     

Echocardiographic evaluation of cardiac function in the fetus

The development of high-resolution ultrasound has allowed detailed examination of the fetal heart. The accuracy of fetal echocardiography in the diagnosis of malformations of the fetal heart has been established in the second trimester and, more recently, at a much earlier stage in gestation (Allan et al., 1980; Allan et al., 1981; Simpson, 2000; Huggon et al., 2002). Confirmation of structural abnormalities has usually been by autopsy or by postnatal investigation. This is certainly sufficient for confirmation of structural malformations, but functional evaluation of the fetal heart is far more difficult to validate. Post-mortem studies, by their very nature give little insight into cardiac function and postnatal studies, whilst permitting functional evaluation of the heart, do so under entirely different conditions compared to the circulation in utero. Prior to the advent of ultrasound, fetal data was drawn from invasive animal studies (Pohlman, 1909; Dawes et al., 1954; Barcroft, 1936; Rudolph, 1985). There have been very few invasive studies in the human fetus including some conducted on exteriorised fetuses undergoing termination by hysterotomy (Nyberg and Westin, 1962; Rudolph et al., 1971). Pressure data has been obtained from the human fetus for normal human hearts and in cardiac disease (Johnson et al., 2000; Johnson et al., 1992; Johnson, 1992). However, the vast majority of cardiac functional data in the human fetus has been obtained by non-invasive means, which has almost exclusively been by echocardiography. This article will review some of the techniques that may be used to evaluate fetal cardiac function and will also emphasise some of the limitations of such techniques.     

Accuracy of ultrasound diagnoses in pregnancies complicated by suspected fetal anomalies

Referral of pregnancies complicated by suspected fetal anomalies to level III perinatal centres for further evaluation and management is increasing as use of real-time ultrasound spreads, but the sensitivity and specificity of the prenatal diagnoses made in this population are unknown. We undertook a prospective study that followed pregnancies referred to a designated programme dealing with suspected fetal abnormalities. Follow-up of 257 pregnancies revealed that 282 separate anomalies were accurately diagnosed in 212 cases. Normal anatomy was correctly predicted in 42 cases, 16 per cent of the referred population. False-positive and false-negative rates were 1.5 per cent (4/257) and 2 per cent (1/46), respectively. However, 37 per cent of those infants born with anomalies had additional problems not prenatally detected by ultrasound. These results indicate that prenatal ultrasound diagnoses are remarkably accurate overall but that they may be insensitive to associated anomalies in individual cases.     

Doppler in fetal heart failure

Fetal echocardiography has progressed to be able to diagnose many forms of congenital heart disease (CHD) and to assess the prognosis of cardiac lesions based on their anatomy and presentation in utero. Fetal echocardiography is for pregnancies at risk of structural, functional, and rhythm-related fetal heart disease. Routine obstetrical ultrasound screening is critical in the prenatal detection of fetal heart disease/CHD. With or without CHD, fetal heart dysfunction defined as inadequate tissue perfusion may occur. Perinatal problems other than CHD can also be assessed, such as the effects of noncardiac malformations that affect hemodynamics, that is, twin-twin transfusion. Cardiac rhythm can affect cardiac function and outcome, and prenatal diagnosis can be lifesaving. A tool for the assessment of cardiac function is the Cardiovascular Profile Score that combines ultrasonic markers of fetal cardiovascular unwellness based on univariate parameters, which have been correlated with perinatal mortality. This "heart failure score" could potentially be used in much the same way as and in combination with the biophysical profile score. This study will present a summary of fetal Doppler and its place in the diagnosis and assessment of prognosis of fetal heart failure.     

Correlation of prenatal ultrasound diagnosis and pathologic findings in fetuses with trisomy 13

OBJECTIVES: This study was conducted to compare the prenatal ultrasound findings and postmortem pathologic findings of fetuses with trisomy 13. METHODS: Of 22 150 fetal chromosome analyses, 28 fetuses with trisomy 13 were diagnosed between 1990 and 2004. Findings of second-trimester sonography and subsequent fetal autopsy were compared by organ system, and their correlation was assigned to one of three categories based on the degree of agreement. RESULTS: Of the total of 79 abnormalities that were found on autopsy, prenatal sonography showed 48 (60.8%). The agreement was more than 75% of all abnormalities of these systems: central nervous system (CNS) (76.5%), facial abnormalities (76.5%), urinary system (81.8%) and fetal hydrops (100%), whereas the sensitivity of sonography was lower in these organ systems: heart (53.3%), extremities (12.5%) and abdominal abnormalities (33.3%). In 39.2% of the cases, autopsy findings were not detected by sonography. These additional findings at autopsy involved mainly three organ systems: heart, face and extremities. Some ultrasound findings (n = 17) were not verified at autopsy; most of them were quantitative markers (mild ventriculomegaly, mild pyelectasis). CONCLUSION: Our results indicate that thorough sonographic examination of the fetal face (including ears) and extremities (including hands and feet) with an extensive use of fetal echocardiography may increase the sensitivity of prenatal sonography in detecting trisomy 13.     

Three-dimensional ultrasonography in genetic screening and counselling

Three-dimensional ultrasound was introduced in clinical use more than a decade ago. Early attempts in obstetrics were directed at surface rendering of the fetal anatomy, mostly of the face, to detect or exclude fetal anomalies. Recently, several papers have discussed fetal volumetry calculated by three-dimensional ultrasound, which has helped greatly to construct the normal ranges for fetal organ volumes, and which improves fetal weight prediction. According to recent literature, more and more fetal anomalies are diagnosed based only on the findings of three-dimensional ultrasound. However, the role of three-dimensional ultrasound in genetic screening and counselling is still undetermined. In this review, we try to address the capability of three-dimensional ultrasound in a number of anatomic areas, to catalog possible markers in the second-trimester genetic sonogram, and finally to introduce the merits of three-dimensional ultrasound in genetic counselling.     

The influence of prenatal diagnosis on postnatal outcome in patients with structural congenital heart disease

Examination of the fetal heart has become an established part of mid-trimester anomaly scanning. Along side this has emerged the ability to diagnose congenital heart disease in the fetus with accuracy. Despite this, the development of screening programmes to look for fetal cardiac disease has only been partially successful. Furthermore, when detected, there seems to be little survival advantage associated with prenatal diagnosis. Demonstrating such an advantage is complicated by the nature of fetal cardiac disease, which tends to be severe and is often associated with extra-cardiac abnormalities. More selective studies, mostly involving small numbers of cases, are now beginning to demonstrate both improved survival and reduced morbidity in prenatally diagnosed infants presenting to cardiac intensive care units compared to those with a postnatal diagnosis.     

Risk factors for cardiac malformations detected by fetal echocardiography in a tertiary center.

OBJECTIVE: Fetal echocardiography accurately detects congenital cardiac anomalies, but it is costly, time-consuming, and requires highly-skilled operators. Our aim was to define those patients for whom fetal echocardiography is justified. METHODS: The files of 1696 consecutive patients who underwent second- to third-trimester fetal echocardiography at our tertiary center between 1997 and 1999 were reviewed for reason for referral, echocardiography diagnosis, and pregnancy outcome. RESULTS: The patients were categorized by reason for referral into high-and low-risk groups. The high-risk group included 662 patients (39%) with fetal risk factors, 178 (10.5%) with maternal risk factors and 279 (16.5%) with poor obstetric history. The remaining 577 women (34%) were considered low-risk population. These included 282 self-referred women (due to maternal anxiety) who served as control group, 78 women who were referred because of a suspected cardiac malformation on routine second-trimester ultrasound, and 213 women who were referred because of failure to view the heart on second-trimester ultrasound. In 46 women, cardiac anomalies (2.7%) were detected prenatally and confirmed postnatally; most of them (41/46, 89%) were in the low-risk population. Abnormal cardiac findings on second-trimester ultrasound and a diagnosis of a single umbilical artery made the most significant contribution to the detection of cardiac abnormalities (p < 0.001 and p = 0.02, respectively). CONCLUSIONS: Most fetal cardiac malformations occur in the low-risk population. Abnormal view of the fetal heart on routine second-trimester screening is highly predictive of congenital cardiac anomalies.     

Sonographic, pathologic and karyotypic findings in a rare case of placenta fenestrata

Abnormalities of placental shape are occasionally seen on ultrasound. They have not been reported to be associated with abnormalities in fetal anatomy and karyotype. Here, we report on a rare case of placenta fenestrata with triploid karyotype. A 15-year-old patient presented at 21 weeks and 3 days gestation for ultrasound evaluation following an abnormal triple screen and abnormal ultrasound. Multiple fetal abnormalities were noted as well as several cystic areas with pulsatile flow on Doppler ultrasound in the placenta. After termination of the pregnancy, a rare abnormality in the placental shape, placenta fenestrata, was noted. The fetal karyotyping showed a triploid karyotype. This is the first reported case of placenta fenestrata diagnosed on ultrasound. In addition, this is also the first reported case of karyotype abnormality associated with abnormality of placental shape.     

Utility of fetal echocardiogram in high-risk patients

AIM: Patients at high risk of fetal congenital heart disease are commonly referred for second trimester fetal echocardiogram. The objective of this study was to evaluate the utility of routine fetal echocardiogram in high-risk patients after the evaluation of the four-chamber/left ventricular outflow tract (LVOT) views during comprehensive second trimester anatomy ultrasound. METHODS: Second trimester comprehensive anatomy ultrasounds, which included a four-chamber/LVOT view, and subsequent fetal echocardiograms carried out at the Duke University Medical Center from January 1995 and July 2002 were reviewed. Those fetal echocardiograms carried out between 17 and 30 weeks gestation were included in the analysis. RESULTS: A total of 725 individual subjects met the inclusion criteria. Twenty-nine fetal echocardiograms were ultimately reported as abnormal. Of these, 19 had an abnormal four-chamber/LVOT view, four had a suboptimal view and six had a normal view. Of the six patients with a normal four-chamber/LVOT, all had been referred for echocardiogram based on the presence of other significant fetal anomalies noted at the time of second trimester anatomy ultrasound (3), documented aneuploidy (2), and significant fetal arrhythmia (1). CONCLUSION: Utility in carrying out fetal echocardiogram was seen in patients with an abnormal four-chamber/LVOT view, a suboptimal view in a high-risk patient, and the presence of other significant fetal abnormalities. Utility was not seen in patients with pre-existing diabetes mellitus.     

Routine fetal cardiac screening: what are we doing and what should we do?

In many countries, ultrasound examination is used in the second trimester to look for congenital malformations as part of routine prenatal care. While tertiary centres scanning high-risk pregnancies have reported a high degree of accuracy in the detection of congenital heart disease, many studies have shown that cardiac abnormalities are commonly overlooked during routine obstetric evaluation and there still remains a huge variation between centres. The majority of babies with congenital heart disease are born to mothers with no identifiable high-risk factors and so will not be detected unless there is widespread screening of the low-risk population. It is feasible to achieve widespread screening for fetal congenital heart disease in low-risk groups, but this does need commitment and effort from those performing the scans and those teaching them how to examine the heart. Staff performing routine obstetric ultrasound scans should learn a simple technique for examining the fetal heart and to use this in all patients. Links to a tertiary centre can provide support for checking scans of concern as well as for providing training and for obtaining feedback. In addition, an audit system needs to be established in each centre to trace false-positive and false-negative cases as well as to confirm true positives and true negatives.     

Fetal cardiac function assessed by spatio-temporal image correlation

Background  

Three-dimensional (3D) and four-dimensional (4D) ultrasound have been proposed to be valuable tools for the examination of fetal heart. Spatio-temporal image correlation (STIC) is a technique that adds a time component to 3D ultrasound imaging of the fetal heart, so we can evaluate cardiac structures as a 4D cine sequence containing information of one full cardiac cycle. STIC gives the investigator the opportunity to freeze the displayed cardiac loop in end-diastolic and end-systolic phases. By STIC, 3D measurements of both the left and right ventricle can be used to calculate fetal heart stroke volume, cardiac output and ejection fraction, and expressions of cardiac function. The ultimate goal of STIC technique is to improve fetal cardiac function analysis by decreasing the dependency on operator skills required by two-dimensional ultrasound.