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Visualization of the axial plane of the fetal abdomen is mandatory to obtain abdominal biometry in the assessment of fetal growth in the second and third trimesters. The main anatomic landmarks that must be identified in this view include the fetal stomach and the intrahepatic portion of the umbilical vein, which are easily identifiable as they appear anechoic on ultrasound. The gallbladder is the other prominent anechoic structure in this plane. Focused study of the morphological characteristics of, and spatial relationship among, these three anechoic spaces is a simple technique to detect anomalies involving fetal upper abdominal organs. In this review, the sonographic features of those conditions that can be detected using this technique, which was termed the Fetal Examination of the Anechoic Spaces of upper abdomen Technique (FEAST), are classified and illustrated.

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Objective: To determine the prevalence, sonographic spectrum, and clinical significance of echogenic material in the fetal gallbladder in our population.Methods: Sonographic visualization of the fetal gallbladder was attempted in 3894 consecutive third-trimester pregnancies (4026 fetuses). Gallbladder content was classified as clear (anechoic), containing echogenic material that was either diffuse (sludge), or presenting as a single focus or multiple foci (gallstone(s)). Information on the clinical course was obtained by reviewing the medical records or contacting the provider or the parents themselves.Results: During the three and a half-year study period from July 2014 to December 2017, 19 fetuses were identified as having echogenic material in the gallbladder (prevalence 1/211, 0.47%). Among them, echogenic biliary sludge was found in eight fetuses (42%); all eight were asymptomatic and a normal gallbladder was documented postnatally in four of them. Single (n = 3) or multiple (n = 8) echogenic foci were found in 58% of cases, which was associated with a good prognosis and subsequent resolution between 1 and 10 months of life in all cases.Conclusions: The prevalence of echogenic material in the fetal gallbladder in our population was similar to that previously reported in the literature. The prognosis appears to be favorable, with resolution and without subsequent postnatal hepatic or gastrointestinal complications in all cases.

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First-trimester ultrasound findings in 4 fetuses with agnathia-otocephaly complex are described. In addition, information from 3 cases reported in the literature was also reviewed, for a total of 7 cases analyzed. All 7 fetuses presented with agnathia and 6 with ventrocaudal displacement of the ears (melotia/synotia). Four fetuses had holoprosencephaly. In 6 cases, the parents opted for termination of pregnancy. The remaining case resulted in premature delivery at 26 weeks due to severe polyhydramnios and early neonatal death. This report highlights the important role of ultrasound in the identification of agnathia-otocephaly complex in the first trimester of pregnancy.

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INTRODUCTION: Congenital splenic cysts are a rare cause of abdominal cystic masses in the fetus. We describe nine cases of this condition, the largest reported experience to date. A review of the literature for similar cases was also performed. METHODS: Cases of congenital splenic cyst were collected from three prenatal diagnostic centers and from a dedicated website of prenatal diagnosis. Information regarding clinical and sonographic findings was obtained by reviewing ultrasound reports and medical records. An electronic search of the Pubmed/MEDLINE database for similar cases, with subsequent manual cross-referencing, was performed and the relevant information from the articles was retrieved. RESULTS: A total of nine cases were added to the currently existing literature of 32 cases. In all but one of our cases, the prenatal detection of the splenic cyst was made in the third trimester, with a median gestational age at diagnosis of 30 weeks (range 22-37). The splenic cyst was confirmed after delivery in all but one case, which was lost to follow up. Postnatal sonographic examinations performed in the remaining eight cases showed that the cyst increased in size in two (25%), was stable in size in one (12%), decreased in size in one (12%), and completely regressed in the other four cases (50%). No complications associated with the cysts were reported in the infants. CONCLUSIONS: Congenital splenic cyst appears to be a benign condition with no known risk of perinatal complications. Nevertheless, differential diagnosis with other fetal cystic masses of the left upper abdominal quadrant and postnatal sonographic follow up to monitor the size of the cyst are important issues to be considered in the perinatal management of these cases.

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Accurate and timely prenatal diagnosis of spina bifida (SB) is a major goal of modern antenatal care. Prenatal screening for open SB should be first performed at the time of routine first-trimester ultrasound by examining the posterior fossa for obliteration or non-visualization of the fourth ventricle ("intracranial translucency") and cisterna magna. The second step of screening is the second-trimester anatomy scan, at which time the features of the Chiari type II malformation should be looked for, including ventriculomegaly, scalloping of the frontal bones ("lemon" sign), and backward and caudal displacement of the cerebellar vermis with obliteration of the cisterna magna ("banana" sign). In cases with positive findings, evaluation must include a focused examination of the spine for defects. In cases of closed SB and SB occulta, the cranial and posterior fossa features will not be present as they are not associated with leaking of spinal fluid and resultant hindbrain herniation, highlighting the fact that the spine should be examined thoroughly whenever possible during the second-trimester scan. In tertiary fetal medicine centers, two-dimensional and three-dimensional ultrasound allows an accurate determination of the location, type, extent, and upper level of the spinal defect as well as the presence of associated anomalies. Fetal magnetic resonance imaging should be restricted to candidates for intrauterine surgery as part of the preoperative protocol.

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OBJECTIVE: The aim of this study was to determine whether choroid plexus morphology ('butterfly' sign) and biparietal diameter (BPD) are effective sonographic screening tools for holoprosencephaly (HPE) in the first trimester. METHODS: An axial view of the fetal head was obtained routinely to determine the presence of the 'butterfly' sign in pregnancies presenting for sonographic screening at 11-13 weeks of gestation. The same view was also used to obtain BPD measurements. The definitive diagnosis of HPE was established by the sonographic demonstration of an anterior cerebral monoventricular cavity and thalamic fusion. RESULTS: During a 9-year study period, 11 068 live fetuses were screened. There were 11 cases of HPE (prevalence 1/1006); all of them were detected by demonstration of an absent 'butterfly' sign with no false-positive cases. The BPD was less than the 5th percentile in 40% of the cases. CONCLUSIONS: The 'butterfly' sign appears to be a highly sensitive marker for HPE in the first trimester. On the other hand, BPD measurements had a lower sensitivity, implying that microcephaly is not a prominent first-trimester feature in these cases. Incorporation of the 'butterfly' sign into the first trimester anatomy scan is simple and can facilitate the identification of the vast majority of fetuses with HPE in the first trimester.

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We review the sonographic features, antenatal course, and perinatal outcomes in 7 cases of ectopia cordis diagnosed in the first trimester. Four cases were associated with a large omphalocele (pentalogy of Cantrell) and 2 with a body stalk anomaly. The remaining fetus had isolated thoracic ectopia cordis. Two pregnancies were terminated; 2 fetuses died in utero; 2 infants died after delivery; and 1 died at 3 months of age. We conclude that the diagnosis of ectopia cordis can easily be established during the first trimester. In agreement with the currently available literature, the prognosis of ectopia cordis in our series was uniformly poor.

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We describe a new technique that can facilitate the first-trimester examination of the fetal palate using the Volume NT algorithm (Samsung Medison, Seoul, Korea), a program that automatically detects the exact midsagittal plane of the head and is primarily designed for semiautomatic measurement of the nuchal translucency thickness. Three-dimensional (3D) data sets from the fetal face were captured with Volume NT and subsequently reformatted with the Oblique View software to obtain orthogonal views of the primary and secondary palate in coronal and axial planes, respectively. By testing this method in selected 3D data sets obtained retrospectively (n = 12) and prospectively (n = 28), we were able to extract clinically acceptable views of the fetal palate in all cases. This preliminary report shows that with this new 3D automation development, early evaluation of the fetal palate is feasible and reproducible and could be easily incorporated into the first-trimester sonographic protocol once its ability to detect abnormal cases is demonstrated.

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Three-dimensional ultrasound and magnetic resonance imaging are powerful imaging techniques that are used increasingly in evaluating fetal anatomy. In this chapter, we review the main applications of these imaging modalities in current practice and present an overview of the malformations that may benefit from assessment with three-dimensional ultrasound and magnetic resonance imaging.

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Ultrasonography is used routinely during pregnancy to screen and diagnose fetal anomalies. Two-dimensional ultrasound is usually adequate in women at low risk for malformations. When technical factors limit optimal evaluation or a malformation is suspected, further imaging with three-dimensional ultrasound and magnetic resonance imaging is becoming increasingly common. Three-dimensional ultrasound allows the manipulation of data acquired from two-dimensional ultrasound to recreate an infinite number of views, thereby enhancing the ability to evaluate the fetal anatomy. When three-dimensional ultrasound is either unavailable or inadequate, fetal magnetic resonance imaging permits detailed evaluation of the suspected anomaly and assesses the presence of associated anomalies. In this chapter, we review the techniques, advantages, limitations, and clinical applications of these two fetal imaging modalities.

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The purpose of this report is to describe the prenatal sonographic findings in fetuses with hydranencephaly diagnosed during the early stages of disease. Four cases with characteristics of hydranencephaly were retrospectively identified from 2 Latin American fetal medicine referral centers. Information on maternal demographics, sonographic findings, antenatal courses, and pregnancy outcomes was retrieved from the ultrasound reports and medical records. Cases were diagnosed between 21 and 23 weeks' gestation. The sonographic findings were similar in all cases and included absent cerebral hemispheres, which were replaced by homogeneous echogenic material filling the supratentorial space, and preservation of the thalami, brain stem, and cerebellum. The head circumference measurement was within the normal range, but the transverse cerebellar diameter was below the fifth percentile in 3 of the 4 cases. A follow-up scan in 1 of these cases demonstrated the classic anechoic fluid-filled appearance of hydranencephaly 2 weeks after diagnosis. Confirmation of the diagnosis was available in 2 cases, by postmortem examination in 1 and by fetal magnetic resonance imaging in the other. No further investigations were performed in the 2 women who opted for termination of pregnancy. In conclusion, during the early stages of disease, hydranencephaly is characterized by the presence of a large intracranial saclike structure containing homogeneous echogenic material, representing blood and necrotic debris secondary to massive liquefaction of the developing cerebral hemispheres.

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OBJECTIVES: To determine the feasibility of obtaining adequate 3-dimensional (3D) data sets to examine the fetal secondary palate during the second-trimester anatomy scan. METHODS: During a 3-month period, 3D data sets of the fetal secondary palate were obtained from consecutive women undergoing routine second-trimester scans. Only structurally normal singleton fetuses with a normal upper lip on 2-dimensional (2D) sonography were included. Three-dimensional data sets were obtained using a mechanical transducer with a 45° sweep and the same settings as for the standard 2D scan, ideally when the fetus was facing the transducer, with mild extension of the head, and the ultrasound beams projecting caudally to cranially to avoid shadowing from the primary palate or mandible. No additional scanning time was allocated for examination of the palate. Acquired 3D data sets were analyzed offline using dedicated software, and the secondary palate was assessed using the "flipped face" technique. RESULTS: Ninety-seven women met entry criteria and underwent second-trimester scans at a median gestational age of 22 completed weeks (range, 18-23 weeks). In 13 (13.4%) cases, it was not possible to obtain a midsagittal view of the face for capturing 3D volume data sets due to fetal position. Additional factors limiting visualization were shadowing from the primary palate in fetuses with flexion of the head in 30 (30.9%) cases, interposition of, or shadowing from, fetal arms or legs in 11 (11.3%), inability to reproduce a true midsagittal plane in 8 (8.2%), and poor image quality in 1 (1%). Therefore, it was only possible to assess the secondary palate in 34 (35.1%) cases. CONCLUSIONS: It is not feasible to obtain adequate 3D data sets for offline analysis of the fetal secondary palate in almost two-thirds of second-trimester fetuses during the routine scan. However, suboptimal visualization is primarily due to factors related to fetal position rather than equipment or image quality. This finding suggests that a dedicated scan, during which adequate time can be devoted to obtaining a satisfactory position in which the fetal face can be evaluated, may be warranted in high-risk cases.

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OBJECTIVE: To examine patient and provider attitudes toward first trimester nuchal translucency (NT) screening for Down syndrome and to assess how patients consent to screening in a country where abortion is illegal. METHODS: Patients presenting for first trimester ultrasound including NT screening in two obstetric units in Chile completed a questionnaire about their attitudes toward NT screening and perspectives on the consent process. A follow-up questionnaire assessed satisfaction with the test. Prenatal care providers also completed a questionnaire ascertaining their perspectives on NT screening. RESULTS: A total of 107 patients completed the initial questionnaire and 78 completed the follow-up questionnaire. Although 98 (94%) patients desired NT screening only 38 (38%) indicated that they would undergo diagnostic testing if they received screen positive results. Only 3 patients screened positive; however, 15 (20%) participants experienced increased anxiety after the test. Almost all of the 36 providers surveyed indicated that they counsel their patients thoroughly, but 38 (39%) patients reported that they received adequate information. CONCLUSION: NT screening is often performed without patients' full understanding of the implications of potential results and may cause anxiety. Providers should elicit patients' preferences regarding prenatal testing and engage them in shared decision making about whether to undergo screening, particularly when abortion is not an option.

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OBJECTIVE: To report the sonographic findings, prenatal courses, and management options in four cases of monoamniotic twin pregnancy complicated by a discordant, lethal open cranial vault defect. METHODS: Cases were collected from two Latin American fetal medicine referral centers after the sonographic detection of a monoamniotic twin pregnancy in which one fetus was structurally normal and the other had a lethal open cranial vault defect. Three abnormal fetuses had acrania-anencephaly sequence and one had a large occipital encephalocele. The diagnosis was confirmed at referral, at which time umbilical cord entanglement was also diagnosed with color Doppler ultrasound in all cases. RESULTS: Two cases were managed with selective termination, one of which required referral to a fetal surgery center abroad because this option was illegal in Chile. The other case underwent radiofrequency ablation of the fetal intra-abdominal umbilical vessels after the corresponding ethics and legal committees approved the procedure. In both cases, the non-anomalous twin was born after 35 weeks and had no perinatal complications. Expectant management was performed in the other two cases, resulting in the death of the normal twin at 25 weeks. CONCLUSIONS: Monoamniotic twin pregnancy discordant for severe cranial vault defect is a serious condition with a high risk of fetal demise of the structurally normal fetus. Our experience, although limited, suggests that aggressive management with selective termination of the abnormal twin and transection of its umbilical cord in these cases may prevent the demise of the structurally normal co-twin.

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BACKGROUND: Prenatal differential diagnosis of fetal scalp cystic masses is challenging and mainly includes small meningoceles and epidermal cysts. CASE: A second-trimester anatomy scan revealed an extracranial cystic mass measuring 17 × 12 × 10 mm in the fetal occipital region. Three-dimensional datasets were obtained transabdominally and off-line analysis revealed a connection between the cyst and the subarachnoid space through a 5-mm skull defect. The diagnosis of a small meningocele was further confirmed by magnetic resonance imaging in the infant. CONCLUSION: Prenatal three-dimensional ultrasound can be a useful adjunct in the prenatal differentiation between small meningoceles and epidermal cysts.

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OBJECTIVES: To review the sonographic features of spinal anomalies in first-trimester fetuses presenting for screening for chromosomal abnormalities. METHODS: Fetuses with a spinal abnormality diagnosed prenatally or postnatally that underwent first-trimester sonographic evaluation at our institution had their clinical information retrieved and their sonograms reviewed. RESULTS: A total of 21 fetuses complied with the entry criteria including eight with body stalk anomaly, seven with spina bifida, two with Vertebral, Anal, Cardiac, Tracheal, Esophageal, Renal, and Limb (VACTERL) association, and one case each of isolated kyphoscoliosis, tethered cord, iniencephaly, and sacrococcygeal teratoma. One fetus with body stalk anomaly and another with VACTERL association also had a myelomeningocele, making a total of nine cases of spina bifida in our series. Five of the nine (56%) cases with spina bifida, one of the two cases with VACTERL association, and the cases with tethered cord and sacrococcygeal teratoma were undiagnosed in the first trimester. Although increased nuchal translucency was found in seven (33%) cases, chromosomal analysis revealed only one case of aneuploidy in this series. CONCLUSIONS: Fetal spinal abnormalities diagnosed in the first trimester are usually severe and frequently associated with other major defects. The diagnosis of small defects is difficult and a second-trimester scan is still necessary to detect most cases of spina bifida.

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BACKGROUND: The occurrence of a discordant chromosomal abnormality in monozygotic twins is an extremely rare condition. CASE: We report the prenatal sonographic findings and cytogenetic studies in a monochorionic twin pregnancy discordant for severe fetal anomalies. Amniocenteses demonstrated heterokaryotypia for trisomy 13 in monozygotic twins. The pregnancy was managed conservatively, resulting in the delivery of discordant twins at 32 weeks. The structurally normal twin survived without sequelae, but the abnormal twin died shortly after delivery. CONCLUSIONS: This report adds to the literature the second known case of a spontaneously conceived monochorionic twin pregnancy discordant for trisomy 13 and highlights the necessity of sampling both fetuses in cases of monochorionic twins presenting with discordant structural anomalies.

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OBJECTIVE: To report our experience with first-trimester sonographic findings in pregnancies complicated by trisomy 18. METHODS: Proven cases of trisomy 18 undergoing sonographic examination between 11 + 0 and 13 + 6 weeks of gestation were retrospectively identified. Information on maternal demographics, prenatal sonographic findings, and chromosomal analysis results was obtained by reviewing the ultrasound reports and medical records. RESULTS: During the 12-year period from July 1997 to June 2009, 53 cases of full trisomy 18 had first-trimester sonographic examination performed at our institution. All but one fetus displayed one or more abnormal sonographic finding, most commonly increased nuchal translucency thickness (n = 48, 91%). Absent or hypoplastic nasal bone was documented in 53% of the fetuses in which this marker was specifically looked for. Structural anomalies included omphalocele in 11 (21%), abnormal posturing of the hands in three (6%), megacystis in two (4%), and abnormal four-chamber view of the heart in two (4%). Early-onset fetal growth restriction and bradycardia were documented in 14 (26%) and 4 (8%) of the cases, respectively. CONCLUSIONS: Our study demonstrates that a large number of fetuses with trisomy 18 have abnormal sonographic findings in the first trimester. However, the sonographic features usually found in the second-trimester are difficult to detect at an early gestational age. The recognition of the specific first-trimester sonographic pattern of trisomy 18 may allow improved detection of this serious condition in early pregnancy.

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OBJECTIVE: To report our experience with the management of triplet pregnancies complicated by an acardiac fetus. METHODS: During the 5-year period from 2003 to 2008, five cases were identified. The prenatal sonographic findings, antepartum course, antenatal intervention if performed, and perinatal outcome of each case were reviewed. RESULTS: Four pregnancies were spontaneously conceived and one was achieved by in vitro fertilization. Three pregnancies were dichorionic and two were monochorionic, and two acardiac fetuses were part of a monoamniotic set. All cases underwent an early sonographic examination, but the diagnosis was only made in the first trimester in only two cases, as the acardiac fetus was overlooked or inaccurately identified as a dead fetus in the remaining three cases. Early fetal demise before 12 weeks occurred in a case of monochorionic-triamniotic triplets. Percutaneous laser coagulation of the main intra-abdominal vessel was attempted at 17 weeks in two cases, with subsequent delivery after 34 weeks and perinatal survival of three of the four structurally normal fetuses. In the other two pregnancies which were managed expectantly, both were complicated by severe preterm delivery with perinatal survival of three of the four structurally normal fetuses. Overall, there were no survivors in one case, one twin survived in two cases, and two twins survived in the remaining two cases. None of the survivor had neurological sequelae. CONCLUSIONS: The presence of an acardiac fetus in a triplet pregnancy carries a high risk for poor pregnancy outcome, including fetal death and severe preterm labor. Prenatal intervention may be indicated in some cases, but does not prevent fetal death of the pump twin.

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