Afferent venous perfusion of fetal liver: umbilical and portal blood-flow volumes in fetuses born small-for-gestational age.

OBJECTIVE: To quantify the dynamic changes in the afferent venous flow volume of the liver in low-risk pregnancies with fetuses born small-for-gestational age. METHODS: This was a prospective study of low-risk singleton pregnancies with estimated fetal weight (EFW) and birth weight ≤ 10th centile attending for a routine second- or third-trimester ultrasound examination. Their umbilical and portal blood-flow volumes were compared with those of a control group of fetuses born appropriate-for-gestational age from which normal reference ranges were constructed. Absolute and Z-score differences between the groups were assessed. RESULTS: In total, 133 fetuses were included in the study group and 362 in the control group. The mean umbilical blood-flow volume in the study group, both absolute and normalized per kg of EFW, was below that of the appropriate-for-gestational-age fetuses for most of the period of pregnancy studied (overall mean Z-score, -0.82 and -0.84, respectively). In contrast, the mean portal blood-flow volume, per kg of EFW, showed the opposite trend (overall mean Z-score, +0.86), reaching its maximum level (+1.43) in the late third trimester. This resulted in a steep decrease in the mean placental-to-portal-blood-flow volume ratio, from 14.4 at 24 weeks of gestation (above the 60th centile) to 4.7 at 38 weeks of gestation (15th centile), corresponding to Z-scores of +0.4 and -1.02, respectively. CONCLUSION: In fetuses born small-for-gestational age, the ratio of blood-flow volume in the umbilical vein to that in the portal vein decreases consistently during pregnancy, and to a greater extent compared with those born appropriate-for-gestational age, reaching a lower nadir in the third trimester. This additional redistribution of liver perfusion affects negatively fetal growth even in low-risk pregnancy, and should be taken into account when planning delivery. We suggest considering liver venous perfusion as an ancillary tool for monitoring small-for-gestational-age pregnancies. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Congenital hypotonia: systematic approach for prenatal detection.

OBJECTIVES: Congenital hypotonic conditions are rare and heterogeneous, and some are severely debilitating or lethal. Contrary to its prominent postnatal manifestation, the prenatal presentation of hypotonia is frequently subtle, inhibiting prenatal detection. We aimed to characterize the prenatal sonographic manifestation of congenital hypotonia throughout pregnancy, evaluate the yield of diagnostic tests and propose diagnostic models to increase its prenatal detection. METHODS: This was a retrospective observational study of singleton pregnancies with congenital hypotonia, diagnosed either prenatally or immediately after birth, at a single tertiary center between the years 2012 and 2020. Prenatally, hypotonia was diagnosed if a fetus showed sonographic or clinical signs suggestive of hypotonia and had a confirmed underlying genetic condition, or in the absence of a known genetic abnormality if the fetus exhibited multiple prominent signs suggestive of hypotonia. Postnatally, it was diagnosed in neonates displaying reduced muscle tone leading to reduced spontaneous movement, reduced swallowing or feeding difficulty. We reviewed the medical records of pregnant patients carrying fetuses subsequently diagnosed with congenital hypotonia and assessed the yield of ultrasound scans, fetal magnetic resonance imaging, computed tomography and genetic tests. The detection rate of sonographic signs suggesting fetal hypotonia was calculated. The prevalence of non-specific signs, including polyhydramnios, persistent breech presentation, intrauterine growth restriction and maternal perception of reduced fetal movement, were compared between the study group and the local liveborn singleton population. Potential detection rates of different theoretical semiotic diagnostic models, differing in the threshold for referral for a targeted scan, were assessed based on the cohort's data. RESULTS: The study group comprised 26 cases of congenital hypotonia, of which 10 (38.5%) were diagnosed prenatally, and the controls included 95 105 singleton live births, giving a prevalence of congenital hypotonia of 1:3658. Nuchal translucency thickness and the early anomaly scan at 13-17 weeks were normal in all 22 and 23 cases, respectively, in which this was performed. The mid-trimester scan performed at 19-25 weeks was abnormal in four of 24 (16.7%) cases. The overall prenatal detection rate of congenital hypotonic conditions in our cohort was 38.5%. Only cases which underwent a targeted scan were detected and, among the 16 cases which underwent this scan, the prenatal detection rate was 62.5% compared with 0% in pregnancies that did not undergo this scan (P = 0.003). An abnormal genetic diagnosis was obtained in 21 (80.8%) cases using the following modalities: chromosomal microarray analysis (CMA) in two (9.5%), whole-exome sequencing (WES) in 14 (66.7%) and methylation analysis in five (23.8%). CMA was abnormal in 8% (2/25) of the cases and WES detected a causative genetic mutation in 87.5% (14/16) of the cases in which these were performed. Comparison of non-specific signs in the study group with those in the local singleton population showed that hypotonic fetuses had significantly more polyhydramnios (64.0% vs 3.0%, P < 0.0001), persistent breech presentation (58.3% vs 4.2%, P < 0.0001), intrauterine growth restriction (30.8% vs 3.0%, P < 0.0001) and maternal perception of reduced fetal movement (32.0% vs 4.7%, P < 0.0001). Prenatally, the most commonly detected signs supporting a diagnosis of hypotonia were structural anomaly (62.5%, 10/16), reduced fetal movement (46.7%, 7/15), joint contractures (46.7%, 7/15) and undescended testes ≥ 30 weeks (42.9%, 3/7 males). Proposed diagnostic strategies that involved performing a targeted scan for a single non-specific ultrasound sign or two such signs, and then carrying out a comprehensive genetic evaluation for any additional sign, offered theoretical detection rates in our cohort of 88.5% and 57.7%, respectively. CONCLUSIONS: Congenital hypotonic conditions are rare and infrequently detected prenatally. Sonographic signs are visible from the late second trimester. A targeted scan increases prenatal detection significantly. Comprehensive genetic testing, especially WES, is the cornerstone of diagnosis in congenital hypotonia. Theoretical diagnostic models which may increase prenatal detection are provided. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Esophageal atresia and tracheoesophageal fistula: prenatal sonographic manifestation from early to late pregnancy.

OBJECTIVE: Esophageal atresia and/or tracheoesophageal fistula (EA/TEF) remains one of the most frequently missed congenital anomalies prenatally. The aim of our study was to elucidate the sonographic manifestation of EA/TEF throughout pregnancy. METHODS: This was a retrospective study of data obtained from a tertiary center over a 12-year period. The prenatal ultrasound scans of fetuses with EA/TEF were assessed to determine the presence and timing of detection of three principal signs: small/absent stomach and worsening polyhydramnios, both of which were considered as 'suspected' EA/TEF, and esophageal pouch, which was considered as 'detected' EA/TEF. We assessed the yield of the early (14-16 weeks' gestation), routine mid-trimester (19-26 weeks) and third-trimester (≥ 27 weeks) anomaly scans in the prenatal diagnosis of EA/TEF. RESULTS: Seventy-five cases of EA/TEF with available ultrasound images were included in the study. A small/absent stomach was detected on the early anomaly scan in 3.6% of fetuses scanned, without a definitive diagnosis. On the mid-trimester scan, 19.4% of scanned cases were suspected and 4.3% were detected. On the third-trimester anomaly scan, 43.9% of scanned cases were suspected and 33.9% were detected. An additional case with an esophageal pouch was detected on magnetic resonance imaging (MRI) in the mid-trimester and a further two were detected on MRI in the third trimester. In total, 44.0% of cases of EA/TEF in our cohort were suspected, 33.3% were detected and 10.7% were suspected but, eventually, not detected prenatally. CONCLUSIONS: Prenatal diagnosis of EA/TEF on ultrasound is not feasible before the late second trimester. A small/absent stomach may be visualized as early as 15 weeks' gestation. Polyhydramnios does not develop before the mid-trimester. An esophageal pouch can be detected as early as 22 weeks on a targeted scan in suspected cases. The detection rates of all three signs increase with advancing pregnancy, peaking in the third trimester. The early and mid-trimester anomaly scans perform poorly as a screening and diagnostic test for EA/TEF. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Visual biofeedback using transperineal ultrasound in second stage of labor.

OBJECTIVE: To assess the obstetric and psychological effects of visual biofeedback by transperineal ultrasound (TPU) during the second stage of labor. METHODS: This was a prospective, single-center observational study of low-risk nulliparous women with epidural analgesia undergoing vaginal delivery. Visual biofeedback using TPU was provided to 26 women during the second stage of labor. Pushing efficacy was assessed by the change in the angle of progression (AoP) at rest and during pushing efforts, before and after biofeedback. Obstetric outcomes included incidence of perineal tearing, mode of delivery and length of second stage of labor. Psychological outcomes were assessed by self-reported measures obtained during the postnatal hospital stay and included measures of perceived control and maternal satisfaction with childbirth, as well as level of maternal feelings of connectedness with the newborn. Obstetric and psychological results were compared with those of a control group of 69 women who received standard obstetric coaching from midwives. RESULTS: Pushing efficacy increased significantly following visual biofeedback by TPU (P = 0.01), as indicated by a significantly lower delta AoP before (mean, 22.2° (95% CI, 13.9-31.7°)) compared with after (mean, 35.2° (95% CI, 25.9-45.3°)) biofeedback. A significant association was found between visual biofeedback and an intact perineum following delivery (P = 0.03). No significant differences were found between the two groups with regard to mode of delivery or length of the second stage. Feelings of maternal connectedness with the newborn were significantly stronger (P = 0.003) in women who received visual biofeedback than in those who did not. However, perceived control during childbirth and maternal satisfaction with childbirth did not differ significantly between the biofeedback and control groups. CONCLUSIONS: This pilot study suggests that biofeedback using TPU may serve as a complementary tool to coached maternal pushing during the second stage of labor, with obstetric as well as psychological benefits. Further studies are required to confirm our findings and define the optimal duration of the intervention. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Neurodevelopmental outcome of fetal isolated ventricular asymmetry without dilation: a cohort study.

OBJECTIVE: Fetal isolated ventricular asymmetry (IVA) is a relatively common finding in pregnancy, but data regarding its effect on neurodevelopmental outcome are scarce and founded principally on ultrasound-based studies. The purpose of this study was to assess the neurodevelopmental outcome of IVA cases in a magnetic resonance imaging (MRI)-based study. METHODS: Cases referred for fetal brain MRI as part of the assessment of IVA without ventriculomegaly (lateral ventricular atrial diameter ≤ 10 mm), identified during routine ultrasound examination, were assessed for possible inclusion. Asymmetry was defined as a difference in width of ≥ 2 mm between the two lateral ventricles. Forty-three cases were included in the study group and compared with a control group of 94 normal cases without IVA. Children were assessed at ages 13-74 months using the Vineland-II Adaptive Behavior Scales (VABS-II). RESULTS: VABS-II scores were within normal range. There was no significant difference in composite VABS-II score between the study and control groups (106.5 vs 108.0; P = 0.454). VABS-II scores did not differ between the groups when matched for gender and age at VABS-II interview (109.6 in study group vs 107.8 in control group; P = 0.690). CONCLUSION: In cases of IVA without ventriculomegaly on MRI, neurodevelopmental test scores were normal and did not differ from cases without IVA. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Volumetric MRI study of the intrauterine growth restriction fetal brain.

OBJECTIVES: Intrauterine growth restriction (IUGR) is a pathologic fetal condition known to affect the fetal brain regionally and associated with future neurodevelopmental abnormalities. This study employed MRI to assess in utero regional brain volume changes in IUGR fetuses compared to controls. METHODS: Retrospectively, using MRI images of fetuses at 30-34 weeks gestational age, a total of 8 brain regions-supratentorial brain and cavity, cerebral hemispheres, temporal lobes and cerebellum-were measured for volume in 13 fetuses with IUGR due to placental insufficiency and in 21 controls. Volumes and their ratios were assessed for difference using regression models. Reliability was assessed by intraclass correlation coefficients (ICC) between two observers. RESULTS: In both groups, all structures increase in absolute volume during that gestation period, and the rate of cerebellar growth is higher compared to that of supratentorial structures. All structures' absolute volumes were significantly smaller for the IUGR group. Cerebellar to supratentorial ratios were found to be significantly smaller (P < 0.05) for IUGR compared to controls. No other significant ratio differences were found. ICC showed excellent agreement. CONCLUSIONS: The cerebellar to supratentorial volume ratio is affected in IUGR fetuses. Additional research is needed to assess this as a radiologic marker in relation to long-term outcome. KEY POINTS: • IUGR is a pathologic fetal condition affecting the brain • IUGR is associated with long-term neurodevelopmental abnormalities; fetal characterization is needed • This study aimed to evaluate regional brain volume differences in IUGR • Cerebellar to supratentorial volume ratios were smaller in IUGR fetuses • This finding may play a role in long-term development of IUGR fetuses.

Choriovitelline placenta: prenatal sonographic imaging and clinical characteristics.

OBJECTIVES: To describe the fetal sonographic characteristics, in-utero natural history and postnatal outcome of choriovitelline placenta, in which the fetal umbilical vein is replaced by the extra-embryonic vitelline circulation. METHODS: This was a retrospective study of pregnancies examined during the period 2010-2014. Fetuses which presented with sonographic criteria of a downward caudal course of an enlarged vein from the umbilical annulus to the hepatic hilum were followed prospectively. Two-dimensional and three-dimensional color Doppler with high-definition flow were used in order to investigate the extra- and intrahepatic venous system. Ultrasound images and volumes were stored digitally, clinical data were obtained from patients' medical files and telephone interviews were conducted regarding the course of the pregnancy, perinatal data and developmental milestones. RESULTS: Four cases were identified during the study period. The mean ± SD gestational age at diagnosis was 19.5 ± 4.3 (range, 13-23) weeks. The characteristic downward course of the persistent vitelline vein was associated with aneurysmal dilatation and anomalous anatomical configuration of the intrahepatic venous system. One case ended with antepartum death at 28 weeks. The mean gestational age at delivery was 34.6 (±5.0) weeks and the birth weight corresponded to the 57.2nd (± 16.8 SD) centile. In two cases, a thrombotic mass was detected in the portal venous system after birth. One necessitated antithrombotic treatment for 6 months; in the other case, spontaneous resolution occurred 7 days after birth. In the three surviving infants, the persistent extrahepatic vitelline vein regressed gradually within 6 months after birth. Neurodevelopment was normal at follow-up aged 1 year and 7 months, 3 years and 6 months and 5 years and 5 months. CONCLUSION: The main clinical importance of choriovitelline placentation derives from the possible formation of thrombus in the portal venous system. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Fetal umbilical-portal-systemic venous shunt: in-utero classification and clinical significance.

OBJECTIVES: To review our experience with fetal umbilical-portal-systemic venous shunts (UPSVS), to devise an in-utero classification system, and to analyze their clinical and prognostic characteristics. METHODS: This was a retrospective review of cases of UPSVS examined at an academic tertiary referral center over the 14-year period from 2001 to 2014 inclusive. The anatomical origin and drainage of the fetal umbilical, portal, ductus venosus and hepatic venous systems, and the integrity of the intrahepatic portal venous system (IHPVS), were assessed using two- and three-dimensional color Doppler sonography. Fetomaternal clinical characteristics and long-term outcome were investigated by means of medical files, imaging documentation and telephone interviews with the mothers. RESULTS: Forty-four cases with UPSVS were reviewed. Prenatal classification was based on the anatomical origin of the shunt (umbilical, portal or ductal), with cases classified into four types: Type I, umbilical-systemic shunt (n = 9 (20.4%)); Type II, ductus venosus-systemic shunt (n = 19 (43.2%)); and Type III, portal-systemic shunt, divided into two subtypes: Type IIIa, intrahepatic portal-systemic shunt (n = 12 (27.2%)) and Type IIIb, extrahepatic portal-systemic shunt (n = 4 (9.1%)). Each type presented particular clinical and prognostic characteristics. The most important favorable prognostic factors were absence of associated major malformation and presence of the IHPVS. Thus, Type IIIa (intrahepatic portal-systemic shunt) had the best outcome. CONCLUSIONS: Fetal UPSVS are anomalies with a broad spectrum of manifestations and prognoses. Accurate mapping of the IHPVS is paramount for optimizing prenatal counseling and postnatal care. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Fetal Brain MRI: Novel Classification and Contribution to Sonography.

PURPOSE: 1) To evaluate and classify the indications for fetal brain MRI in a tertiary referral center. 2) To assess the contribution of fetal brain MRI to fetal neurosonography. MATERIALS AND METHODS: A retrospective study in a tertiary medical center during a two-year period (2011 - 2012) included pregnant women who underwent fetal brain MRI. MRI was implemented at 32 weeks of gestation unless a severe abnormality possibly requiring earlier medical intervention was suspected. RESULTS: 633 patients were included, 40 (6.3%) underwent repeated examinations with a total of 733 fetal MRI scans. Patients were classified to three main indication cohorts: Suspected primary brain anomaly (52.9%), non-CNS disorders (32.5%) and obstetrical complications (14.6%). These cohorts were further divided into 16 separate groups with lateral ventricle abnormalities being the most common (23.7%), followed by exposure to TORCH (17.5%) and cerebral cortex abnormalities (13%). 149 (19.3%) fetal MRI scans demonstrated additional findings. Repeated examinations were commonly implemented in complicated monochorionic-biamniotic (MCBA) twin pregnancies (34.6%) and in cases of supra-tentorial cysts (19%). The average gestational age for MRI scan in the MCBA group was 26 ±â€Š5 weeks in comparison to ≥ 31st weeks in all other groups (p < 0.001). CONCLUSION: The current study describes a detailed picture of fetal brain MRI indications. Most patients were referred because of CNS anomalies. The impressive diversity of 16 separate entities emphasizes the expanding use of fetal brain MRI. Complicated MCBA pregnancies, which may have dramatic events, constitute a unique challenge due to early and repetitive MRI examinations and may serve as a role model for the contribution of fetal MRI during antenatal evaluation. The contribution of MRI to prenatal evaluation in various indications is discussed.

Can Ultrasound Performed in Prolonged Second Stage of Labor Predict the Difficulty and Success Rates of Operative Vaginal Delivery?

OBJECTIVE: To evaluate different sonographic methods for the prediction of the difficulty and the success of operative vaginal delivery (OPD). MATERIALS AND METHODS: A prospective study was performed on 45 term singleton uncomplicated pregnancies with prolonged 2nd stage of delivery with cephalic presentation. Measurements of the fetal head, relations between the fetal head and maternal pelvic parameters during rest and during maternal pushing were taken using translabial ultrasound. RESULTS: 29 cases of OPD were successful and 4 cases failed ending in cesarean section. The passage of the biparietal diameter (BPD) of the infrapubic line (IPL) was statistically correlated with the success of OPD. Head station, passage of the BPD of the IPL, percentage of head after the IPL, circumference of head after IPL were all correlated with the difficulty of OPD. When the distance between the widest diameter of the head and the IPL is < 1.2 cm, there is a 90 % probability of success of OPD. When that distance is > 3.3 cm, there is 90 % probability of cesarean section. When the percentage of head beyond the IPL was > 54 %, there was 90 % probability of successful OPD. DISCUSSION: Translabial ultrasound is useful in the prediction of the difficulty and the success of OPD. The higher the extent of head that passed the IPL, the less difficult the OPD and the greater the success rate of the OPD.

Prenatal Brain Imaging in Isolated vs. Complicated Club Foot: A Cohort Study.

Purpose: Talipes equinovarus (TEV) is a common birth defect. Differentiation between isolated and complex TEV is fundamental due to its effect on prognosis. Association between TEV and poor neurological outcome is more prominent in complex cases and highlights the significance of brain evaluation. The aim of the current study was to evaluate the contribution of fetal brain MRI to sonographic evaluation. Materials and Methods: In this retrospective study we evaluated charts of all pregnant patients referred for fetal brain MRI due to fetal TEV between 1/1/2011 and 12/31/14 in a single tertiary referral center. Isolated and complex TEV were differentiated according to associated anomalies. Brain US and MRI results were compared. Results: 28 pregnant patients were included with an average gestation and parity of 2.5 and 1.5, respectively. Both isolated and complicated TEV groups included 14 fetuses after initial TEV diagnosis on anatomical survey. Brain sonography and MRI were normal among 12/14 patients with isolated TEV while two patients were later diagnosed with mild ventriculomegaly. US brain evaluation has revealed pathologic findings in 4 (28.6 %) cases in the complicated TEV group, while MRI demonstrated abnormal findings in 8 (57.1 %) fetuses with notable severity diversity. In 6 cases, MRI diagnosed additional pathologies which were not demonstrated by US. Conclusion: Brain fetal MRI is an efficient tool during antenatal evaluation of complicated TEV with a high percentage of additional findings not demonstrated songraphically while its efficacy in isolated cases is in doubt. The current study expands the relevance of fetal brain MRI in cases of non-CNS anomalies.

Head progression distance in prolonged second stage of labor: relationship with mode of delivery and fetal head station.

OBJECTIVE: To evaluate the clinical significance of fetal head progression distance (HPD), measured by transperineal ultrasound, during prolonged second stage of labor. METHODS: In this prospective study, a single operator, who was blinded to the results of the digital examination, assessed using transperineal ultrasound women at ≥ 37 weeks of gestation with failure to progress in the second stage of labor. Patients had an empty urinary bladder and the examination was performed during maternal pushing. HPD was defined as the length of the line perpendicular to the infrapubic line that would connect it to the lowest part of the fetal bony skull. We analyzed associations between HPD and digital examination of fetal head station, fetomaternal characteristics, mode of delivery and perinatal outcome. RESULTS: Sixty-five patients in prolonged second stage of labor participated in the study. The overall mean HPD was 6.50 (± 1.35; 95% CI, 6.16-6.83) cm. No correlation was found between HPD and head position or mode of delivery, but HPD was positively correlated with fetal head station and neonatal head circumference measured after delivery. Logistic regression and receiver-operating characteristics curve analysis demonstrated no significant predictive value of HPD with respect to mode of delivery. CONCLUSION: Although HPD in prolonged second stage of labor could not predict mode of delivery, it may have a role as an ancillary tool for fetal head station assessment.

Pubic arch angle in prolonged second stage of labor: clinical significance.

OBJECTIVE: To evaluate the clinical significance of the pubic arch angle (PAA) measured by transperineal ultrasound during prolonged second stage of labor. METHODS: We evaluated prospectively 62 women ≥ 37 weeks of gestation with failure to progress in the second stage of labor. Transperineal ultrasound (transverse plane) was used to measure the pubic arch angle. Correlations with fetomaternal characteristics, mode of delivery and perinatal outcome were evaluated. RESULTS: The mean PAA was 101.1° (± 13.1°; range, 80°-135°). We found a negative correlation with maternal age. Patients with an occipitotransverse fetal position had a significantly smaller angle compared with those with occipitoanterior positions (94.3° ± 5.5° vs. 103.2° ± 14.8°, P < 0.05), as did those with operative deliveries compared with those with spontaneous vaginal delivery (97.1° ± 11.5° vs. 110.1° ± 14.0°, P < 0.05). The prediction of operative delivery in prolonged second stage of labor by receiver-operating characteristics curve using PAA alone yielded an area under the curve of 0.75. The predicted probability for operative delivery increased as PAA decreased, with an odds ratio of 0.933 for each decrease in angle of 1°. CONCLUSION: Our study suggests a correlation between the PAA and mode of delivery in prolonged second stage of labor. This may be used as an adjunctive parameter when considering delivery mode.

Late diagnosis of fetal central nervous system anomalies following a normal second trimester anatomy scan.

OBJECTIVE: The aim of this study was to describe the nature of central nervous system (CNS) anomalies diagnosed during the third trimester following a normal anatomy scan at 21-24 weeks of gestation. METHODS: Retrospective cohort study of all pregnant women referred to the fetal medicine unit at Sheba Medical Center between 2005 and 2011 due to fetal CNS anomalies detected at the late second and third trimesters following a normal anatomy scan at 21-24 weeks of gestation. RESULTS: During the study period, 47 patients were diagnosed with fetal CNS anomalies at a median gestational age of 31.1 weeks (range 24-38). The four most common anomalies found included intracranial cysts (19%), mild ventriculomegaly (15%), absence or dysgenesis of the corpus callosum (10%), and intracerebral hemorrhage (10%). Other CNS anomalies detected in this group of patients included hydrocephalus, Dandy walker malformation, large cysterna magna, microcephalus with lissencephaly, craniosynestosis, periventricular pseudocysts, global brain ischemia, cerebellar hypoplasia, and sub-ependymal nodule. CONCLUSIONS: Fetal brain continues to evolve throughout gestation, and therefore, some of the CNS anomalies can be diagnosed only during late second and third trimesters of pregnancy. Consequently, in patients who have a third trimester scan for any reason, assessment of the fetal CNS should be considered.

Early Fetal Corpus Callosum: Demonstrating Normal Growth and Detecting Pathologies in Early Pregnancy.

BACKGROUND AND PURPOSE: A malformed corpus callosum carries a risk for abnormal neurodevelopment. The advent of high-frequency transducers offers the opportunity to assess corpus callosum development in early pregnancy. The aim of the study was to construct a reference chart of the fetal corpus callosum length on ultrasound between 13 and 19 weeks of gestation and to prospectively examine growth patterns in pathologic cases. MATERIALS AND METHODS: We performed a prospective cross-sectional study between 2020 and 2022 in well-dated, low-risk, singleton pregnancies between 13 and 19 weeks of gestation. A standardized image was obtained in the midsagittal plane. Imaging criteria were used as a confirmation of the early corpus callosum. Measurements were taken by 4 trained sonographers. Intra- and interobserver variability was assessed. Corpus callosum length in centiles were calculated for each gestational week. RESULTS: One hundred eighty-seven fetuses were included in the study. All cases met inclusion criteria. At 13 weeks of gestation, the margins of the early corpus callosum were sufficiently clear to be measured in 80% (20/25) of fetuses. A cubic polynomial regression model best described the correlation between corpus length and gestational age. The correlation coefficient (r 2) was 0.929 (P < .001). Intra- and interobserver variability had high interclass correlation coefficients (>0.99). Presented is the earliest published case of agenesis of corpus callosum and a case of dysgenetic corpus callosum in Rubinstein-Taybi syndrome. CONCLUSIONS: Provided is a nomogram of the early fetal corpus callosum. Applying imaging criteria helped to identify a case of complete agenesis of the corpus callosum as early as 14 weeks.

Comparison of ex-vivo high-resolution episcopic microscopy with in-vivo four-dimensional high-resolution transvaginal sonography of the first-trimester fetal heart.

OBJECTIVE: To compare the capability of three-dimensional (3D) reconstructed images produced by high-resolution episcopic microscopy (HREM) with that of in-vivo four-dimensional high-resolution transvaginal sonography (4D-HRTVS) to discern morphological features of the first-trimester human fetal heart. METHODS: This was a prospective study of fetal hearts between 9 and 14 weeks' gestation. For ex-vivo 3D analysis, 30 human fetal hearts (at 9 + 0 to 14 + 6 weeks) were retrieved from surgical terminations of pregnancy. The specimens were embedded in resin and episcopic ('block-face') imaging was used to obtain a digital volume dataset (HREM) using 3-micron slicing. 4D-HRTVS was performed in 28 separate pregnancies at 10 + 2 to 14 + 0 weeks using a Voluson E8 ultrasound machine with volumetric transvaginal RIC 6-12-MHz transducers. Heart volumes obtained by both methods were compared to assess their ability to demonstrate first-trimester cardiac morphology. Comparisons were made in the transverse and sagittal planes, and using volume rendering. RESULTS: All hearts were structurally normal, although abdominal situs was not examined in the isolated hearts that underwent HREM. 4D-HRTVS demonstrated each of the complete five transverse cardiac views in 32-86% of cases. HREM showed four features unique to the first-trimester human heart: prominent atrial appendages, spiral ventricular arrangement, prominent coronary arteries and thickened arterial walls. 4D-HRTVS could demonstrate the first two, but ultrasound resolution was too poor to quantify wall thickness and demonstrate coronary arteries in the 3-5-mm diameter heart. CONCLUSIONS: 4D-HRTVS showed limited morphological features of the first-trimester fetal heart compared with HREM. HREM provides a gold standard of ex-vivo imaging against which developments in ultrasound resolution could be compared.

3-Dimensional demonstration of fetal anal canal and sphincter.

PURPOSE: To identify the fetal anal canal and sphincter using 3-dimensional (3 D) ultrasound. MATERIALS AND METHODS: 3 D volumes of the fetal pelvis were acquired prospectively in 52 fetuses between 10 and 39 gestational weeks. A standard method for evaluating the fetal anal canal and sphincter was developed. Measurements of mucosal and muscular circumferences and the length of the anal canal were taken. RESULTS: The anal canal was demonstrated in 46 out of 50 patients (92 %). The sonographic characteristics of the anal canal in the axial plane appear like a "target sign" with an echogenic mucosa in the center, the hypoechoic internal sphincter muscle surrounding it and an outer echogenic circle reflecting the external sphincter. Measurements of mucosal and internal sphincter circumferences and the length of the anal canal demonstrated linear growth during pregnancy (p < 0.01). One case of anal atresia was demonstrated. CONCLUSION: The fetal anal canal can be visualized when a systematic analysis is performed using a 3 D volume dataset.

Role of three-dimensional ultrasound measurement of the optic tract in fetuses with agenesis of the septum pellucidum.

OBJECTIVES: To construct reference ranges for fetal optic tract mean diameter and to report measurements in fetuses with agenesis of the septum pellucidum (SP). METHODS: Three-dimensional volumes of the optic chiasm were acquired in 98 normal fetuses during routine sonographic examination at 21-36 weeks' gestation and the diameters of the posterior left and right optic tracts were measured offline. A polynomial regression approach (mean and SD model) was used to compute reference charts for the mean fetal optic tract diameter measurements. In addition, 23 volumes were acquired in fetuses with SP agenesis for offline measurement of optic tract diameter. Complete follow-up was obtained in 13 of these 23 cases. RESULTS: In normal fetuses, the optic tract diameter increased linearly throughout gestation. There was no evidence of increased variability with gestational age (constant SD). Normal charts and equations for Z-score calculation were constructed. Among the 13 fetuses with SP agenesis and complete follow-up, nine had normal measurements, of which eight had normal vision postnatally. Four had hypoplastic optic tract, defined as mean optic tract diameter Z-score below - 3. Of these, two underwent termination of pregnancy and pathological examination confirmed hypoplasia of the tract, one showed signs of hypoplasia at magnetic resonance imaging and postnatal examination confirmed blindness, and one had a hypoplastic measurement for only one tract and was born with poor vision and abnormal bilateral eye movements. CONCLUSION: We present new reference charts for mean fetal optic tract diameter. In fetuses with agenesis of the SP, sonography of the optic tract might be a useful tool to assess its development and may help in prenatal counseling.