ISUOG Practice Guidelines (updated): sonographic examination of the fetal central nervous system. Part 1: performance of screening examination and indications for targeted neurosonography

Genetic etiology and pregnancy outcomes of fetuses with central nervous system anomalies

PURPOSE

To investigate genetic etiology and pregnancy outcomes of fetal central nervous system (CNS) anomalies.

METHODS

217 fetuses with CNS anomalies were included in our cohort from January 2016 to December 2022. 124 cases received karyotyping and 73 cases simultaneously underwent copy number variant sequencing (CNV-seq). Dynamic ultrasound screening and pregnancy outcomes were followed up, including neonates' neurodevelopmental outcomes.

RESULTS

(1) 20 types of CNS anomalies were revealed by ultrasound and the most common was ventriculomegaly. (2) 14 (11.3%) of 124 cases were found chromosomal abnormalities by karyotyping, and copy number variations (CNVs) were revealed in 13 (17.8%) of 73 cases by CNV-seq. Fetuses with non-isolated CNS anomalies had a higher detection rate (DR) of abnormal karyotypes and CNVs than those with isolated CNS anomalies (25.0% vs. 4.8%; 35.0% vs. 11.3%) (P < 0.05). And the DR of abnormal karyotypes was significantly higher in multiple CNS anomalies than in single CNS anomaly (16.7% vs. 2.8%, P < 0.05), while there were no significant differences in the DR of CNVs. (3) Through dynamic ultrasound, 12 cases were further found progression or additional malformations. (4) Pregnancy outcomes of 209 cases were obtained, including 136 (65.1%) live births, 3 (1.4%) intrauterine fetal deaths, and 70 (33.5%) terminated. Two neonatal deaths at 6 months and one infant with motor and intellectual disabilities were finally found after long-term follow-up.

CONCLUSION

Genetic analysis combined with dynamic ultrasound screening and multidisciplinary consultation plays an important role in evaluating the prognosis of fetal CNS anomalies, especially for those with multiple CNS or extracranial abnormalities.

Effects of umbilical vein flow on midbrain growth and cortical development in late onset fetal growth restricted fetuses: a prospective cross-sectional study

OBJECTIVES

To investigate midbrain growth, including corpus callusum (CC) and cerebellar vermis (CV) and cortical development in late fetal growth restricted (FGR) subclassified according to the umbilical vein blood flow (UVBF) values.

METHODS

This was a prospective study on singleton fetuses late FGR with abnormal placental cerebral ratio (PCR). FGR fetuses were further subdivided into normal (≥fifth centile) and abnormal (

RESULTS

The study cohort included 60 late FGR, 31 with normal UVBF/AC and 29 with abnormal UVBF/AC values. The latter group showed significant differences in CC (median (interquartile range (IQR) normal 0.96 (0.73-1.16) vs. abnormal UVBF/AC 0.60 (0.47-0.87); p<0.0001)), CV (normal 1.04 (0.75-1.26) vs. abnormal UVBF (AC 0.76 (0.62-1.18)); p=0.0319), SF (normal 0.83 (0.74-0.93) vs. abnormal UVBF/AC 0.56 (0.46-0.68); p<0.0001), POF (normal 0.80 (0.71-0.90) vs. abnormal UVBF/AC l 0.49 (0.39-0.90); p≤0.0072) and CF (normal 0.83 (0.56-1.01) vs. abnormal UVBF/AC 0.72 (0.53-0.80); p<0.029).

CONCLUSIONS

Late onset FGR fetuses with of reduced umbilical vein flow showed shorter CC and CV length and a delayed cortical development when compared to those with normal umbilical vein hemodynamics. These findings support the existence of a link between abnormal brain development and changes in umbilical vein circulation.

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Key Words

• cerebellar vermis
• corpus callosum
• cortical folding
• fetal growth restriction
• neurosonography
• umbilical vein flow

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MESH Headings

• Humans
• Female
• Fetal Growth Retardation/diagnostic imaging
• Fetal Growth Retardation/physiopathology
• Pregnancy
• Prospective Studies
• Cross-Sectional Studies
• Umbilical Veins/diagnostic imaging
• Adult
• Ultrasonography, Prenatal/methods
• Mesencephalon/diagnostic imaging
• Mesencephalon/blood supply
• Mesencephalon/embryology
• Fetal Development/physiology
• Cerebral Cortex/diagnostic imaging
• Cerebral Cortex/blood supply
• Cerebral Cortex/embryology

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Affiliation(s)

Ilenia Mappa Department of Obstetrics and Gynecology, Fondazione Policlinico Tor Vergata, Università di Roma Tor Vergata, Rome, Italy
Maria Chiara Marra Department of Obstetrics and Gynecology, Fondazione Policlinico Tor Vergata, Università di Roma Tor Vergata, Rome, Italy
Maria Elena Pietrolucci Department of Obstetrics and Gynecology, Fondazione Policlinico Tor Vergata, Università di Roma Tor Vergata, Rome, Italy
Jia Li Angela Lu Department of Obstetrics and Gynecology, Fondazione Policlinico Tor Vergata, Università di Roma Tor Vergata, Rome, Italy
Francesco D'Antonio Department of Obstetrics and Gynecology, Università di Chieti, Chieti, Italy
Giuseppe Rizzo Department of Obstetrics and Gynecology, Fondazione Policlinico Tor Vergata, Università di Roma Tor Vergata, Rome, Italy Department of Obstetrics and Gynecology, Università di Chieti, Chieti, Italy

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Genetic etiology of agenesis of the corpus callosum: a retrospective single-center cohort analysis of 114 fetuses

PURPOSE

The identification and prognosis of the agenesis of the corpus callosum (ACC) for prenatal consultation are complex and currently unclear. This study aims to explore the correlated genetic mutations of prenatal ACC.

METHODS

We retrospectively analyzed 114 prenatal cases of ACC. All cases (n = 114) were subjected to chromosomal microarray analysis (CMA), and 66 CMA-negative cases underwent prenatal exome sequencing (pES) for further analysis.

RESULTS

CMA was diagnosed positively in 15/114 (13.2%) cases and pES was diagnosed positively in 24/66 (36.4%) CMA-negative cases. The detection rate of genetic causes between complete and partial ACCs was not significantly different (P > 0.05). Between isolated and non-isolated (other anomalies present) ACCs, the diagnostic rate of pES in non-isolated cases was significantly higher (P < 0.001), while CMA results did not differ (P > 0.05). The diagnostic rate of CMA was significantly increased in cases combined with intracranial and extracranial malformations (P = 0.014), while no CMA positivity was detected in cases combined with only intracranial malformations.

CONCLUSION

For fetuses with prenatal ACC, further pES analysis should be recommended after negative CMA results. Chromosome abnormalities are less likely to occur when ACC with only intracranial malformations combined.

Evidence of brain injury in fetuses of mothers with preterm labor with intact membranes and preterm premature rupture of membranes

BACKGROUND

Brain injury and poor neurodevelopment have been consistently reported in infants and adults born before term. These changes occur, at least in part, prenatally and are associated with intra-amniotic inflammation. The pattern of brain changes has been partially documented by magnetic resonance imaging but not by neurosonography along with amniotic fluid brain injury biomarkers.

OBJECTIVE

This study aimed to evaluate the prenatal features of brain remodeling and injury in fetuses from patients with preterm labor with intact membranes or preterm premature rupture of membranes and to investigate the potential influence of intra-amniotic inflammation as a risk mediator.

STUDY DESIGN

In this prospective cohort study, fetal brain remodeling and injury were evaluated using neurosonography and amniocentesis in singleton pregnant patients with preterm labor with intact membranes or preterm premature rupture of membranes between 24.0 and 34.0 weeks of gestation, with (n=41) and without (n=54) intra-amniotic inflammation. The controls for neurosonography were outpatient pregnant patients without preterm labor or preterm premature rupture of membranes matched 2:1 by gestational age at ultrasound. Amniotic fluid controls were patients with an amniocentesis performed for indications other than preterm labor or preterm premature rupture of membranes without brain or genetic defects whose amniotic fluid was collected in our biobank for research purposes matched by gestational age at amniocentesis. The group with intra-amniotic inflammation included those with intra-amniotic infection (microbial invasion of the amniotic cavity and intra-amniotic inflammation) and those with sterile inflammation. Microbial invasion of the amniotic cavity was defined as a positive amniotic fluid culture and/or positive 16S ribosomal RNA gene. Inflammation was defined by amniotic fluid interleukin 6 concentrations of >13.4 ng/mL in preterm labor and >1.43 ng/mL in preterm premature rupture of membranes. Neurosonography included the evaluation of brain structure biometric parameters and cortical development. Neuron-specific enolase, protein S100B, and glial fibrillary acidic protein were selected as amniotic fluid brain injury biomarkers. Data were adjusted for cephalic biometrics, fetal growth percentile, fetal sex, noncephalic presentation, and preterm premature rupture of membranes at admission.

RESULTS

Fetuses from mothers with preterm labor with intact membranes or preterm premature rupture of membranes showed signs of brain remodeling and injury. First, they had a smaller cerebellum. Thus, in the intra-amniotic inflammation, non-intra-amniotic inflammation, and control groups, the transcerebellar diameter measurements were 32.7 mm (interquartile range, 29.8-37.6), 35.3 mm (interquartile range, 31.2-39.6), and 35.0 mm (interquartile range, 31.3-38.3), respectively (P=.019), and the vermian height measurements were 16.9 mm (interquartile range, 15.5-19.6), 17.2 mm (interquartile range, 16.0-18.9), and 17.1 mm (interquartile range, 15.7-19.0), respectively (P=.041). Second, they presented a lower corpus callosum area (0.72 mm2 [interquartile range, 0.59-0.81], 0.71 mm2 [interquartile range, 0.63-0.82], and 0.78 mm2 [interquartile range, 0.71-0.91], respectively; P=.006). Third, they showed delayed cortical maturation (the Sylvian fissure depth-to-biparietal diameter ratios were 0.14 [interquartile range, 0.12-0.16], 0.14 [interquartile range, 0.13-0.16], and 0.16 [interquartile range, 0.15-0.17], respectively [P<.001], and the right parieto-occipital sulci depth ratios were 0.09 [interquartile range, 0.07-0.12], 0.11 [interquartile range, 0.09-0.14], and 0.11 [interquartile range, 0.09-0.14], respectively [P=.012]). Finally, regarding amniotic fluid brain injury biomarkers, fetuses from mothers with preterm labor with intact membranes or preterm premature rupture of membranes had higher concentrations of neuron-specific enolase (11,804.6 pg/mL [interquartile range, 6213.4-21,098.8], 8397.7 pg/mL [interquartile range, 3682.1-17,398.3], and 2393.7 pg/mL [interquartile range, 1717.1-3209.3], respectively; P<.001), protein S100B (2030.6 pg/mL [interquartile range, 993.0-4883.5], 1070.3 pg/mL [interquartile range, 365.1-1463.2], and 74.8 pg/mL [interquartile range, 44.7-93.7], respectively; P<.001), and glial fibrillary acidic protein (1.01 ng/mL [interquartile range, 0.54-3.88], 0.965 ng/mL [interquartile range, 0.59-2.07], and 0.24 mg/mL [interquartile range, 0.20-0.28], respectively; P=.002).

CONCLUSION

Fetuses with preterm labor with intact membranes or preterm premature rupture of membranes had prenatal signs of brain remodeling and injury at the time of clinical presentation. These changes were more pronounced in fetuses with intra-amniotic inflammation.

Fetal Cerebral Ventriculomegaly: A Narrative Review and Practical Recommendations for Pediatric Neurologists

Fetal cerebral ventriculomegaly is one of the most common fetal neurological disorders identified prenatally by neuroimaging. The challenges in the evolving landscape of conditions like fetal cerebral ventriculomegaly involve accurate diagnosis and how best to provide prenatal counseling regarding prognosis as well as postnatal management and care of the infant. The purpose of this narrative review is to discuss the literature on fetal ventriculomegaly, including postnatal management and neurodevelopmental outcome, and to provide practice recommendations for pediatric neurologists.

Fetal neuroimaging applications for diagnosis and counseling of brain anomalies: Current practice and future diagnostic strategies

Advances in fetal brain neuroimaging, especially fetal neurosonography and brain magnetic resonance imaging (MRI), allow safe and accurate anatomical assessments of fetal brain structures that serve as a foundation for prenatal diagnosis and counseling regarding fetal brain anomalies. Fetal neurosonography strategically assesses fetal brain anomalies suspected by screening ultrasound. Fetal brain MRI has unique technological features that overcome the anatomical limits of smaller fetal brain size and the unpredictable variable of intrauterine motion artifact. Recent studies of fetal brain MRI provide evidence of improved diagnostic and prognostic accuracy, beginning with prenatal diagnosis. Despite technological advances over the last several decades, the combined use of different qualitative structural biomarkers has limitations in providing an accurate prognosis. Quantitative analyses of fetal brain MRIs offer measurable imaging biomarkers that will more accurately associate with clinical outcomes. First-trimester ultrasound opens new opportunities for risk assessment and fetal brain anomaly diagnosis at the earliest time in pregnancy. This review includes a case vignette to illustrate how fetal brain MRI results interpreted by the fetal neurologist can improve diagnostic perspectives. The strength and limitations of conventional ultrasound and fetal brain MRI will be compared with recent research advances in quantitative methods to better correlate fetal neuroimaging biomarkers of neuropathology to predict functional childhood deficits. Discussion of these fetal sonogram and brain MRI advances will highlight the need for further interdisciplinary collaboration using complementary skills to continue improving clinical decision-making following precision medicine principles.

Outcome of partial agenesis of corpus callosum

BACKGROUND

The diagnosis of corpus callosum anomalies by prenatal ultrasound has improved over the last decade because of improved imaging techniques, scanning skills, and the routine implementation of transvaginal neurosonography.

OBJECTIVE

Our aim was to investigate all cases of incomplete agenesis of the corpus callosum and to report the sonographic characteristics, the associated anomalies, and the perinatal outcomes.

STUDY DESIGN

We performed a retrospective analysis of cases from January 2007 to December 2017 with corpus callosum anomalies, either referred for a second opinion or derived from the prenatal ultrasound screening program in a single tertiary referral center. Cases with complete agenesis were excluded from the analysis. Standardized investigation included a detailed fetal ultrasound including neurosonogram, fetal karyotyping (standard karyotype or array comparative genomic hybridization) and fetal magnetic resonance imaging. The pregnancy outcome was collected, and pathologic investigation in case of termination of the pregnancy or fetal or neonatal loss was compared with the prenatal findings. The pregnancy and fetal or neonatal outcomes were reported. The neurologic assessment was conducted by a pediatric neurologist using the Bayley Scales of Infant Development-II and the standardized Child Development Inventory when the Bayley investigation was unavailable.

RESULTS

Corpus callosum anomalies were diagnosed in 148 cases during the study period, 62 (41.9%) of which were excluded because of complete agenesis, and 86 fetuses had partial agenesis (58.1%). In 20 cases, partial agenesis (23.2%) was isolated, whereas 66 (76.7%) presented with different malformations among which 29 cases (43.9%) were only central nervous system lesions, 21 cases (31.8%) were non-central nervous system lesions, and 16 cases (24.3%) had a combination of central nervous system and non-central nervous system lesions. The mean gestational age at diagnosis for isolated and non-isolated cases was comparable (24.29 [standard deviation, 5.05] weeks and 24.71 [standard deviation, 5.35] weeks, respectively). Of the 86 pregnancies with partial agenesis, 46 patients opted for termination of the pregnancy. Neurologic follow-up data were available for 35 children. The overall neurologic outcome was normal in 21 of 35 children (60%); 3 of 35 (8.6%) showed mild impairment and 6 of 35 (17.1%) showed moderate impairment. The remaining 5 of 35 (14.3%) had severe impairment. The median duration of follow-up for the isolated form was 45.6 months (range, 36-52 months) and 73.3 months (range, 2-138 months) for the nonisolated form.

CONCLUSION

Partial corpus callosum agenesis should be accurately investigated by neurosonography and fetal magnetic resonance imaging to describe its morphology and the associated anomalies. Genetic anomalies are frequently present in nonisolated cases. Efforts must be taken to improve ultrasound diagnosis of partial agenesis and to confirm its isolated nature to enhance parental counseling. Although 60% of children with prenatal diagnosis of isolated agenesis have a favorable prognosis later in life, they often have mild to severe disabilities including speech disorders at school age and behavior and motor deficit disorders that can emerge at a later age.

Prenatal diagnosis and postnatal outcome of closed spinal dysraphism

OBJECTIVE

To evaluate the prenatal diagnosis of closed dysraphism (CD) and its correlation with postnatal findings and neonatal adverse outcomes.

METHODS

A retrospective cohort study including pregnancies diagsnosed with fetal CD by prenatal ultrasound (US) and magnetic resonance imaging (MRI) at a single tertiary center between September 2011 and July 2021.

RESULTS

CD was diagnosed prenatally and confirmed postnatally in 12 fetuses. The mean gestational age of prenatal imaging was 24.2 weeks, in 17% the head circumference was ≤fifth percentile and in 25% the cerebellar diameter was ≤fifth percentile. US findings included banana sign in 17%, and lemon sign in 33%. On MRI, posterior fossa anomalies were seen in 33% of cases, with hindbrain herniation below the foramen magnum in two cases. Mean clivus-supraocciput angle (CSA) was 74°. Additional anomalies outside the CNS were observed in 50%. Abnormal foot position was demonstrated prenatally in 17%. Neurogenic bladder was present in 90% of patients after birth.

CONCLUSION

Arnold Chiari II malformation and impaired motor function can be present on prenatal imaging of fetuses with CD and may be associated with a specific type of CD. Prenatal distinction of CD can be challenging. Associated extra CNS anomalies are frequent and the rate of neurogenic urinary tract dysfunction is high.

An Easy and Effective Method for Evaluating the Position of Conus Medullaris: Counting the Number of Vertebral Ossification Center Below the End of Conus Medullaris

OBJECTIVE

This study aimed to ascertain the conus medullaris position by counting the number of ossification centers in the vertebral bodies below the conus medullaris endpoint (N) and assess its utility in screening for closed spinal dysraphism and tethered cord syndrome.

METHODS

A total of 900 normal fetuses and 146 fetuses with closed spinal dysraphism or tethered cord syndrome were included in this study. The N values were tallied and compared along the spinal longitudinal plane. The receiver operating characteristic curve was utilized, and the cut-off value of N was analyzed.

RESULTS

The counting of N was successfully performed in 856 normal and 146 abnormal fetuses. In the normal group, an increase in N with gestational age was observed. Specifically, in the subgroup of 17-20 wk fetuses, N was ≥6 in 117 out of 131 cases. This figure increased to 211 out of 213 in 21-24 wk and 512 out of 512 in 25-41 wk, respectively. Cases with N ≥7 accounted for 715 out of 856 fetuses in the 17-41 wk range. In the abnormal group, N was less than 7 in 152 out of 163 fetuses, showing statistical differences between the two groups. With a cut-off value of 6.5, specificity and sensitivity reached 93.3% and 83.5%.

CONCLUSIONS

The counting of N was found to be a straightforward and efficient method for evaluating the position of the conus medullaris.

Fetal brain development in pregnancies complicated by gestational diabetes mellitus

OBJECTIVES

Gestational diabetes mellitus (GDM) carries an increased risk of neurocognitive impairment in offsprings. However, the contribution of maternal hyperglycemia in affecting fetal brain development is not fully elucidated yet. The aim of this study was to evaluate fetal brain and sulci development in pregnancies complicated by GDM.

METHODS

Prospective observational study including 100 singleton pregnancies complicated by GDM and 100 matched controls. All fetuses underwent neurosonography at 29-34 weeks of gestation, including the assessment of the length of the corpus callosum (CC), cerebellar vermis (CV), Sylvian (SF), parieto-occipital (POF) and calcarine fissures (CF). Sub-group analysis according to the specific treatment regimen adopted (n 67 diet vs. 33 insulin therapy) was also performed.

RESULTS

Fetuses from mothers with GDM under insulin therapy had a smaller CC (35.54 mm) compared to both controls (40 mm; p<0.001) and women with GDM under diet (39.26 mm; p=0.022) while there was no difference in the HC between the groups. Likewise, when corrected for HC, CV depth was smaller in fetuses with GDM both under insulin therapy (7.03 mm) and diet (7.05 mm,) compared to controls (7.36 mm; p=0.013). Finally, when assessing the sulci development of the brain SF (p≤0.0001), POF (p≤0.0001) and CF (p≤0.0001) were significantly smaller in fetuses with maternal GDM. Post-hoc analysis showed that fetuses of GDM mothers requiring insulin therapy had significantly lower values of SF (p=0.032), POF (p=0.016) and CF (p=0.001).

CONCLUSIONS

Pregnancies complicated by GDM showed a peculiar pattern of fetal brain growth and cortical development and these changes, which are more evident in those requiring insulin supplementation.

Artificial intelligence assistance for fetal development: evaluation of an automated software for biometry measurements in the mid-trimester

BACKGROUND

This study presents CUPID, an advanced automated measurement software based on Artificial Intelligence (AI), designed to evaluate nine fetal biometric parameters in the mid-trimester. Our primary objective was to assess and compare the CUPID performance of experienced senior and junior radiologists.

MATERIALS AND METHODS

This prospective cross-sectional study was conducted at Shenzhen University General Hospital between September 2022 and June 2023, and focused on mid-trimester fetuses. All ultrasound images of the six standard planes, that enabled the evaluation of nine biometric measurements, were included to compare the performance of CUPID through subjective and objective assessments.

RESULTS

There were 642 fetuses with a mean (±SD) age of 22 ± 2.82 weeks at enrollment. In the subjective quality assessment, out of 642 images representing nine biometric measurements, 617-635 images (90.65-96.11%) of CUPID caliper placements were determined to be accurately placed and did not require any adjustments. Whereas, for the junior category, 447-691 images (69.63-92.06%) were determined to be accurately placed and did not require any adjustments. In the objective measurement indicators, across all nine biometric parameters and estimated fetal weight (EFW), the intra-class correlation coefficients (ICC) (0.843-0.990) and Pearson correlation coefficients (PCC) (0.765-0.978) between the senior radiologist and CUPID reflected good reliability compared with the ICC (0.306-0.937) and PCC (0.566-0.947) between the senior and junior radiologists. Additionally, the mean absolute error (MAE), percentage error (PE), and average error in days of gestation were lower between the senior and CUPID compared to the difference between the senior and junior radiologists. The specific differences are as follows: MAE (0.36-2.53 mm, 14.67 g) compared to (0.64- 8.13 mm, 38.05 g), PE (0.94-9.38%) compared to (1.58-16.04%), and average error in days (3.99-7.92 days) compared to (4.35-11.06 days). In the time-consuming task, CUPID only takes 0.05-0.07 s to measure nine biometric parameters, while senior and junior radiologists require 4.79-11.68 s and 4.95-13.44 s, respectively.

CONCLUSIONS

CUPID has proven to be highly accurate and efficient software for automatically measuring fetal biometry, gestational age, and fetal weight, providing a precise and fast tool for assessing fetal growth and development.

Clinical Practice Guidelines and Recommendations by the World Association of Perinatal Medicine and Perinatal Medicine Foundation: Reporting Suspected Findings from Fetal Central Nervous System Examination

These guidelines follow the mission of the World Association of Perinatal Medicine, in collaboration with the Perinatal Medicine Foundation, which brings together groups and individuals worldwide, with the aim to improve prenatal detection of central nervous system anomalies and the appropriate referral of pregnancies with suspected fetal anomalies. In addition, this document provides further guidance for healthcare practitioners with the goal of standardizing the description of ultrasonographic abnormal findings.

Prenatal evaluation of genetic variants in fetuses with small head circumference: A single-center retrospective study

OBJECTIVES

To comprehensively evaluate the contributions of numerical chromosomal abnormality, copy number variant (CNV), and sequence variant (SV) to fetuses with small head circumference in a Chinese cohort using chromosome microarray analysis and whole exome sequencing.

METHODS

A total of 157 fetuses with small heads defined as head circumference < - 2 standard deviation (SD) were recruited between October 2014 and March 2023. We used the ultrasonic measurement parameter Z-score to define small head as possible microcephaly (3 < Z ≤ -2), microcephaly (-5 < Z ≤ -3), or pathologic microcephaly (Z ≤ -5). Ultrasound findings and genetic results were analyzed.

RESULTS

The overall diagnostic yield of chromosomal abnormalities by microarray analysis was 13 %. Whole exome sequencing revealed eight novel variants and two interesting candidate genes and provided a 25.4 % incremental yield compared with microarray analysis. Of the detected SVs, 56 % were de novo and the most common inheritance pattern was autosomal dominant inheritance presented in 11/16 fetuses. Compared with isolated small heads, non-isolated small heads had a significantly higher detection rate of chromosomal abnormalities (16 % vs. 3.0 %, P = 0.049) but not SVs (24 % vs. 5.5 %, P = 0.126). Subgroup analysis showed that intracranial anomalies had a similar high detection rate of SVs in fetuses with all small heads subgroups while no chromosomal abnormalities and causative SVs were found in fetuses with isolated possible microcephaly.

CONCLUSIONS

Ultrasound findings of small fetal head circumference < 3 SD below the mean, especially those with intracranial structural abnormalities, indicate the need for genetic counseling. Genetic variants, mainly copy number variants and SV, may be responsible for the substantial proportion of small fetal head circumference, while most are de novo. Whole exome sequencing and microarray analysis are effective diagnostic approaches for this population.

Normal values of the fronto-occipital relationship in fetuses between 18 and 40 weeks at two maternal fetal medicine units: Bogotá, Colombia

OBJECTIVE

To establish nomograms for linear measurements of the frontal and occipital horns of the lateral ventricle and their relationship, in pregnant patients between 18 and 40 weeks of gestation and having attended 2 units of Maternal Fetal Medicine in Bogotá-Colombia.

METHODOLOGY

A descriptive cross-sectional study with an analytical component was carried out on pregnant patients who utilized the ultrasound services at 2 Maternal-Fetal Medicine units in Bogotá, between 18 and 40 weeks of pregnancy who underwent measurement. From the anterior and posterior horns of the lateral ventricles, the fronto-occipital ratio was calculated at each gestational week, and nomograms were created for each of these variables.

RESULTS

Nine hundred and seventy-eight patients were included in the study. The distance of the frontal horns ranged between 6.9 and 51.6 mm with a mean of 19.1 ± 5.8 mm; that of the occipital horns had a measurement between 8.7 and 53 mm with a mean of 28, 1 ± 8.9 mm; on the other hand, the fronto-occipital ratio (FOR) yielded a mean of 0.365 ± 0.067 (0.136-0.616) without bearing any relation to gestational age. The trend of normal values for the studied population is displayed, plotted in percentile curves and nomograms for each gestational age.

CONCLUSION

The measurement of the frontal and occipital horns, and the calculation of the fronto-occipital relationship is technically possible between 18 and 40 weeks, finding that the anterior and posterior horns have a positive linear relationship with gestational age. Contrarily, the FOR does not correlate with the gestational age, it was possible to establish a table of percentiles that allows determining the normal values for these measurements during pregnancy.

Genotype-phenotype correlation study of structural abnormalities in a fetal brain caused by a novel KDM4B variant

BACKGROUND

Fetal ventriculomegaly (VM), a common brain structure malformation detected during prenatal ultrasound diagnosis, is associated with an increased risk of neurodevelopmental disorders (NDDs) after birth. KDM4B encodes a lysine-specific demethylase that interacts with histone H3K23me3. Variations in KDM4B are reportedly associated with human NDDs; however, only 11 such patients have been reported. Herein, we report a fetus with VM and agenesis of the corpus callosum (ACC), which suggests that KDM4B plays an important role in fetal brain development.

METHODS

Fetal skin tissue and parental peripheral venous blood samples were collected. Whole-exome and Sanger sequencing were performed to analyze fetal germline variants. Human 293T cells transfected with wild-type or mutant KDM4B were used for western blotting (WB) to analyze protein expression levels.

RESULTS

An insertion variant of KDM4B, NM_015015.3: c.2889_2890insGAGAGCATCACGGTGAGCTGTGGGGTGGGGCAGGGGGCGGGGGGAGGCTGGGAGCACAGTGACAACCTGTACCCC, was identified in the fetal tissue; however, the parents carried the wild-type gene. The WB results indicated significantly reduced expression of the mutant protein, likely owing to decreased stability.

CONCLUSIONS

The structural abnormalities in the brain of the studied fetus may be attributed to an insertion variant of KDM4B. This study highlights the importance of screening for KDM4B variants and considering potential copy number variations when observing VM or ACC in prenatal ultrasound imaging.

Artificial Intelligence in Obstetric Anomaly Scan: Heart and Brain

BACKGROUND

The ultrasound scan represents the first tool that obstetricians use in fetal evaluation, but sometimes, it can be limited by mobility or fetal position, excessive thickness of the maternal abdominal wall, or the presence of post-surgical scars on the maternal abdominal wall. Artificial intelligence (AI) has already been effectively used to measure biometric parameters, automatically recognize standard planes of fetal ultrasound evaluation, and for disease diagnosis, which helps conventional imaging methods. The usage of information, ultrasound scan images, and a machine learning program create an algorithm capable of assisting healthcare providers by reducing the workload, reducing the duration of the examination, and increasing the correct diagnosis capability. The recent remarkable expansion in the use of electronic medical records and diagnostic imaging coincides with the enormous success of machine learning algorithms in image identification tasks.

OBJECTIVES

We aim to review the most relevant studies based on deep learning in ultrasound anomaly scan evaluation of the most complex fetal systems (heart and brain), which enclose the most frequent anomalies.

Too short or too long: impact of corpus callosal measurement on prenatal counseling

Linked article: This Correspondence comments on Corroenne et al. Click here to view the article.

Perforation of cavum septi pellucidi in open spina bifida and need for hydrocephalus treatment by 1 year of age

OBJECTIVE

In-utero repair of an open neural tube defect (ONTD) reduces the risk of developing severe hydrocephalus postnatally. Perforation of the cavum septi pellucidi (CSP) may reflect increased intraventricular pressure in the fetal brain. We sought to evaluate the association of perforated CSP visualized on fetal imaging before and/or after in-utero ONTD repair with the eventual need for hydrocephalus treatment by 1 year of age.

METHODS

This was a retrospective cohort study of consecutive patients who underwent laparotomy-assisted fetoscopic ONTD repair between 2014 and 2021 at a single center. Eligibility criteria for surgery were based on those of the Management of Myelomeningocele Study (MOMS), although a maternal prepregnancy body mass index of up to 40 kg/m2 was allowed. Fetal brain imaging was performed with ultrasound and magnetic resonance imaging (MRI) at referral and 6 weeks postoperatively. Stored ultrasound and MRI scans were reviewed retrospectively to assess CSP integrity. Medical records were reviewed to determine whether hydrocephalus treatment was needed within 1 year of age. Parametric and non-parametric tests were used as appropriate to compare outcomes between cases with perforated CSP and those with intact CSP as determined on ultrasound at referral. Logistic regression analysis was performed to assess the predictive performance of various imaging markers for the need for hydrocephalus treatment.

RESULTS

A total of 110 patients were included. Perforated CSP was identified in 20.6% and 22.6% of cases on preoperative ultrasound and MRI, respectively, and in 26.6% and 24.2% on postoperative ultrasound and MRI, respectively. Ventricular size increased between referral and after surgery (median, 11.00 (range, 5.89-21.45) mm vs 16.00 (range, 7.00-43.5) mm; P < 0.01), as did the proportion of cases with severe ventriculomegaly (ventricular width ≥ 15 mm) (12.7% vs 57.8%; P < 0.01). Complete CSP evaluation was achieved on preoperative ultrasound in 107 cases, of which 22 had a perforated CSP and 85 had an intact CSP. The perforated-CSP group presented with larger ventricles (mean, 14.32 ± 3.45 mm vs 10.37 ± 2.37 mm; P < 0.01) and a higher rate of severe ventriculomegaly (40.9% vs 5.9%; P < 0.01) compared to those with an intact CSP. The same trends were observed at 6 weeks postoperatively for mean ventricular size (median, 21.0 (range, 13.0-43.5) mm vs 14.3 (range, 7.0-29.0) mm; P < 0.01) and severe ventriculomegaly (95.0% vs 46.8%; P < 0.01). Cases with a perforated CSP at referral had a lower rate of hindbrain herniation (HBH) reversal postoperatively (65.0% vs 88.6%; P = 0.01) and were more likely to require treatment for hydrocephalus (89.5% vs 22.7%; P < 0.01). The strongest predictor of the need for hydrocephalus treatment within 1 year of age was lack of HBH reversal on MRI (odds ratio (OR), 36.20 (95% CI, 5.96-219.12); P < 0.01) followed by perforated CSP on ultrasound at referral (OR, 23.40 (95% CI, 5.42-100.98); P < 0.01) and by perforated CSP at 6-week postoperative ultrasound (OR, 19.48 (95% CI, 5.68-66.68); P < 0.01).

CONCLUSIONS

The detection of a perforated CSP in fetuses with ONTD can reliably identify those cases at highest risk for needing hydrocephalus treatment by 1 year of age. Evaluation of this brain structure can improve counseling of families considering fetal surgery for ONTD, in order to set appropriate expectations about postnatal outcome. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Fetal insular measurements in pregnancy with estimated fetal weight <10th centile and childhood neurodevelopmental outcomes

BACKGROUND

A growing body of evidence suggests that fetal growth restriction is associated with changes in brain structures as a result of chronic hypoxia. However, less is known about the effects of growth restriction on the fetal insula, particularly in less severely affected late-onset growth-restricted fetuses.

OBJECTIVE

This study aimed to (1) compare sonographic insular measurements between fetal-growth restricted, small-for-gestational-age, and appropriate-for-gestational-age control fetuses; and (2) evaluate the association of sonographic insular measurements with perinatal and neurodevelopmental outcomes in fetuses categorized as fetal-growth restricted or small-for-gestational-age.

STUDY DESIGN

This was a cohort study of singleton nonanomalous pregnancies with an estimated fetal weight <10th centile. Using data from the last examination before delivery, fetal insular depth, Sylvian fissure depth, hypoechoic insular zone thickness, circumference, and area were measured. All measurements were adjusted for by head circumference. Neurodevelopmental outcomes were evaluated at 2 to 3 years of age using the Bayley-III scales. Kruskal-Wallis H tests were performed to compare insular measurements between groups. Paired t tests were used to compare insular measurements between appropriate-for-gestational-age fetuses and gestational age-matched growth-restricted fetuses. Insular measurements for patients with and without an adverse perinatal outcome were compared using independent-samples t-tests. Spearman correlations were performed to evaluate the relationship of insular measurements to the percentile scores for each of the 5 Bayley-III subscales and to a summative percentile of these subscales.

RESULTS

A total of 89 pregnancies were included in the study; 68 of these pregnancies had an estimated fetal weight <10th percentile (fetal-growth restricted: n=39; small-for-gestational-age: n=29). The appropriate-for-gestational-age cohort consisted of 21 pregnancies. The gestational age at measurement was similar between fetal-growth restricted and small-for-gestational-age groups, but lower in the appropriate-for-gestational-age group. Differences between groups were noted in normalized insular depth, Sylvian fissure depth, and hypoechoic insular zone (P<.01). Normalized insular depth and hypoechoic insular zone circumference were larger in the growth-restricted cohort (P<.01). Normalized Sylvian fissure depth was smaller in the growth-restricted cohort (P<.01). There were no significant differences in insular measurements between pregnancies with and without an adverse perinatal outcome. Bayley-III results were available in 32 of the growth-restricted cases. Of all insular measurements, hypoechoic insular zone circumference was inversely correlated with the adaptive behavior Bayley-III score.

CONCLUSION

In our cohort, fetuses with estimated fetal weight <10th percentile had smaller Sylvian fissure depths and larger insular depths and hypoechoic insular zone circumferences than normally grown controls. A larger hypoechoic insular zone circumference was substantially correlated with worse neurodevelopmental outcomes in early childhood. We speculate that enlargement of this region may be an indication of accelerated neuronal maturation in growth-restricted fetuses with mild hypoxia.

Prevalence of corpus callosum pathology in an unselected population. Should assessment of the corpus callosum be included in the routine 20 weeks scan?

OBJECTIVES

To determine the prevalence of abnormalities of the corpus callosum (AbnCC) in a non-selected population, to propose a systematic screening protocol for AbnCC in all populations through direct assessment, and to describe the follow-up and prognosis of all AbnCC cases diagnosed in our clinical setting.

METHODS

This was a retrospective review of the prevalence of AbnCC over 11 years. We included a sagittal assessment of the corpus callosum (CC) in the second-trimester scan. AbnCC was classified into complete agenesis of CC (ACC) and dysgenesis of CC (DCC; including small, partial agenesis, thick and with lipoma).

RESULTS

Of the 38,586 second-trimester scans performed during our screening, 43 cases of AbnCC were detected (prevalence of 0.8/1000). Of the AbnCC cases, 10 cases were identified as ACC (29.40%) and 24 as DCC (70.59%). Follow-up investigations showed that in the 43 cases with AbnCC, 76.5% had other associated ultrasound abnormalities, 26.5% had genetic abnormalities, 11.8% had other MRI abnormalities, and 25% of the children had neurodevelopmental delays (8.8% of the total), which were severe in only one case.

CONCLUSIONS

AbnCC is found in approximately 0.8/1000 of cases in an unselected population. The findings suggest that systematic and direct assessment of the CC as part of screening ultrasound in the second trimester of gestation should be recommended as a routine practice.

Revisiting MOMS criteria for prenatal repair of spina bifida: upper gestational-age limit should be raised and assessment of prenatal motor function rather than anatomical level improves prediction of postnatal function

OBJECTIVES

To determine if the lower-extremity neurological motor function level in fetuses with open spina bifida deteriorates within the 4-week interval between a first prenatal motor assessment at around 22 weeks of gestation and a second evaluation, prior to 'late' prenatal surgery, defined as surgery at 26-28 weeks and, in certain situations, up to 30 weeks, and to assess the association between prenatal presurgical motor-function level, anatomical level of the lesion and postnatal motor-function level.

METHODS

This was a two-center cohort study of 94 singleton fetuses with open spina bifida which underwent percutaneous repair using the skin-over-biocellulose for antenatal fetoscopic repair (SAFER) technique between December 2016 and January 2022. All women underwent two prenatal systematic ultrasound evaluations, approximately 4 weeks apart, with the second one being performed less than 1 week before surgery, and one postnatal evaluation via physical examination within 2 months of birth. Motor-function classification was from spinal level T12 to S1, according to key muscle function. Each leg was analyzed separately; in case of discrepancy between the two legs, the worst motor-function level was considered for analysis. Motor-function-level evaluations were compared with each other and with the anatomical level as observed on ultrasound. Independent predictors of a postnatal reduction in motor-function level were assessed using a logistic regression model.

RESULTS

Prenatal motor-function level was assessed at a median gestational age of 22.5 (interquartile range (IQR), 20.7-24.3) and 26.7 (IQR, 25.4-27.3) weeks, with a median interval of 4.0 (IQR, 2.4-6.0) weeks. The median gestational age at surgery was 27.0 (IQR, 25.9-27.6) weeks and the postnatal examination was at median age of 0.8 (IQR, 0.3-5.4) months. There was no significant difference in motor-function level between the two prenatal evaluations (P = 0.861). We therefore decided to use the second prenatal evaluation for comparison with postnatal motor function and anatomical level. Overall, prenatal and postnatal motor function evaluations were significantly different from the anatomical level (preoperative assessment, P = 0.0015; postnatal assessment, P = 0.0333). Comparing prenatal with postnatal motor-function level, we found that 87.2% of babies had similar or improved motor function compared with that prior to prenatal surgery. On logistic regression analysis, lower anatomical level of defect and greater difference between anatomical level and prenatal motor-function level were identified as independent predictors of postnatal motor function (odds ratio, 0.237 (95% CI, 0.095-0.588) (P = 0.002) and 3.44 (95% CI, 1.738-6.813) (P < 0.001), respectively).

CONCLUSIONS

During a 4-week interval between first ultrasound evaluation and late fetal surgical repair of open spina bifida, motor function does not change significantly, suggesting that late repair, ≥ 26 weeks, does not impact negatively on motor-function outcome. Compared with the anatomical level of the lesion, preoperative neurological motor-function assessment via ultrasound is more predictive of postnatal motor function, and should be included in preoperative counseling. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Percutaneous fetal endoscopic third ventriculostomy for severe isolated cerebral ventriculomegaly

OBJECTIVE

To demonstrate the feasibility and preliminary results of percutaneous fetal endoscopic third ventriculostomy (ETV) in human fetuses (pfETV) with isolated progressive and/or severe bilateral cerebral ventriculomegaly (IPSBV).

METHODS

The initial results of pfETV for IPSBV were described. Perioperative, perinatal and postnatal variables were described. The Ages and Stages Questionnaire (ASQ-3), 3rd edition (ASQ-3) was used for follow-up of all infants.

RESULTS

Successful pfETV was performed in 10/11 (91%) fetuses, at a median gestational age (GA) of 28.7 weeks (25.3-30.7). There were no perioperative complications. After pfETV, 70% (7/10) of the fetuses had a decreased or stabilized lateral ventricle atria|lateral ventricle's atria. The median GA at delivery was 38.2 weeks (35.9-39.3). There were no perinatal complications. The postnatal ventriculoperitoneal shunt rate was 80% (8/10). Among neonates/infants who had prenatal stabilization or a decrease in the LVAs, 4 (4/7: 57.1%) had abnormal scores on the ASQ-3. Among neonates/infants that experienced prenatal increases in the LVAs, all of them (3/3: 100%) had abnormal scores on the ASQ-3.

CONCLUSION

Percutaneous ETV is feasible in human fetuses with progressive and/or severe cerebral ventriculomegaly and seems to be a safe procedure for both the mother and the fetus.

Simple prenatal imaging predictors for postnatal cerebrospinal fluid diversion surgery in fetuses undergoing in utero surgery for spina bifida

OBJECTIVES

To determine simple prenatal imaging parameters that can easily be acquired to predict the need for postnatal CSF diversion (PCD) surgery in fetuses undergoing open fetal surgery for open spina bifida (OSB).

METHODS

All fetuses with OSB that underwent open fetal surgery between June 2017 and June 2021 with available follow-up outcomes were included. Imaging parameters including clivus-supraocciput angle (CSA) on magnetic resonance imaging, transcerebellar diameter (TCD) and lateral ventricle size (Vp) on ultrasound (US), were collected pre- and postoperatively. The requirement for PCD surgery was determined at 1 year of age. The predictive strength of each parameter was determined by Receiver Operating Characteristic curve analysis.

RESULTS

Among 36 babies eligible for the analyses, 41.7% required PCD by one year of age. Pre-operative Vp (AUC 0.71; 95% confidence interval [CI] 0.54-0.88; p = 0.03), TCD (AUC 0.72; 95% CI 0.55-0.89; p = 0.02) and CSA (AUC 0.72; 95% CI 0.51-0.93; p = 0.04) were fair predictors for PCD surgery. After fetal surgery, TCD (AUC 0.93; 95% CI 0.83-1.00; p < 0.0001) and CSA (AUC 0.94; 95% CI 0.83-1.00; p = 0.0005) were outstanding predictors of PCD, whereas post-operative Vp was a fair predictor (AUC 0.71, 95% CI 0.54-0.88, p = 0.03).

CONCLUSION

Post-operative CSA and TCD were outstanding predictors for the need for PCD surgery.

Sonographic demonstration of the sulci and gyri on the convex surface in normal fetuses using 3D-ICRV rendering technology

PURPOSE

To demonstrate morphological alteration of the sulci and gyri on the convex surface in normal fetuses using innovative three-dimensional inversion and Crystalvue and Realisticvue (3D-ICRV) rendering technology.

MATERIALS AND METHODS

3D fetal brain volumes were collected from low-risk singleton pregnancies between 15+0 and 35+6 gestational weeks. Volumes were acquired from the transthalamic axial plane by transabdominal ultrasonography and were then post-processed with Crystalvue, Realisticvue rendering software and inversion mode. Volume quality was assessed. The anatomic definition of the sulci and gyri was determined according to location and orientation. The morphology alteration and sulcus display rates were recorded in sequential order of gestational weeks. Follow-up data were collected in all cases.

RESULTS

294 of 300 fetuses (294 brain volumes) (98%) with qualified fetal brain volumes were included (n=294, median 27 gestational weeks). 6 fetuses with unsatisfactory 3D-ICRV image quality were excluded. The morphology of the sulci and gyri on the brain convex surface could be demonstrated clearly on 3D-ICRV images. The Sylvian fissure was the first structure to be recognized. From 25 to 30 weeks, other sulci and gyri became visible. An ascending trend in the display rate of the sulci was found in this period. Follow-up showed no detectable anomalies.

CONCLUSION

3D-ICRV rendering technology is different from traditional 3D ultrasound. It can provide vivid and intuitive prenatal visualization of the sulci and gyri on the brain surface. Moreover, it may offer new ideas for neurodevelopment exploration.

Natural history and mid-term neurodevelopmental outcome of fetuses with isolated mild ventriculomegaly diagnosed in the second half of pregnancy

INTRODUCTION

Prenatal diagnosis and counseling of isolated ventriculomegaly (VM) represent a considerable challenge. We aimed to analyze the intrauterine evolution, associated anomalies, and neurodevelopmental outcome using the Battelle Development Inventory (BDI) of fetuses with an initial diagnosis of isolated mild VM.

MATERIAL AND METHODS

Retrospective cohort study of fetuses diagnosed with mild isolated VM (10 -12 mm) between 2012 and 2016 in a tertiary hospital. In 2018, parents were invited to complete the structured BDI test for the neurodevelopmental evaluation of their children in five domains (personal-social skills, adaptive behavior, psychomotor ability, communication, and cognition). Results exceeding two standard deviations were considered abnormal and referred to an expert neuropediatrician.

RESULTS

We identified 43 cases of mild isolated VM. In 5 (11%), structural abnormalities were detected during prenatal follow-up, being related to non-regressive forms (p = .01) and bilateral VM (p = .04). The BDI test was completed by 19/43 (44%). The global score was abnormal in 10/19 (53%). Of them, the neuropediatrician confirmed a neurodevelopmental delay solely in 3 cases that had already been diagnosed with neurological disorders. The most affected domains were gross motor skills (63%), personal-social (63%), and adaptive domains (47%). Communicative and cognitive areas were abnormal in 26% of cases.

CONCLUSION

In fetuses with isolated mild VM detected in the second half of pregnancy, 53% had an abnormal BDI test at 2-6 years, but a neurological disorder was only confirmed in the 30% of them.

Pathogenic/likely pathogenic copy number variations and regions of homozygosity in fetal central nervous system malformations

OBJECTIVE

To explore pathogenic/likely pathogenic copy number variations (P/LP CNVs) and regions of homozygosity (ROHs) in fetal central nervous system (CNS) malformations.

METHODS

A cohort of 539 fetuses with CNS malformations diagnosed by ultrasound/MRI was retrospectively analyzed between January 2016 and December 2019. All fetuses were analyzed by chromosomal microarray analysis (CMA). Three cases with ROHs detected by CMA were subjected to whole-exome sequencing (WES). The fetuses were divided into two groups according to whether they had other structural abnormalities. The CNS phenotypes of the two groups were further classified as simple (one type) or complicated (≥ 2 types).

RESULTS

(1) A total of 35 cases with P/LP CNVs were found. The incidence of P/LP CNVs was higher in the extra-CNS group [18.00% (9/50)] than in the isolated group [5.32% (26/489)] (P < 0.01), while there was no significant difference between the simpletype and complicated-type groups. (2) In the simple-type group, the three most common P/LP CNV phenotypes were holoprosencephaly, Dandy-Walker syndrome, and exencephaly. There were no P/LP CNVs associated with anencephaly, microcephaly, arachnoid cysts, ependymal cysts, or intracranial hemorrhage. (3) Only four cases with ROHs were found, and there were no cases of uniparental disomy or autosomal diseases.

CONCLUSION

The P/LP CNV detection rates varied significantly among the different phenotypes of CNS malformations, although simple CNS abnormalities may also be associated with genetic abnormalities.

Neurosonographic Measurements of the Fetal Anterior Complex in Singleton Pregnancies

OBJECTIVE

To construct reference ranges of the fetal cerebral anterior complex, including ventricular index (VI), anterior horn of lateral ventricle width (AW), and cavum septi pellucidi (CSP) width, as a function of gestational age (GA), in Thai fetuses.

METHODS

Low-risk pregnancies were recruited to measure fetal anterior complex on axial transventricular and coronal transcaudate planes using transabdominal ultrasound. The downside and upside hemisphere were defined as cerebral hemisphere located distal and proximal to the transducer, respectively. The five variables, downside/upside VI, downside/upside AW and CSP width, were measured from each fetus. Best-fit models in predicting mean and standard deviation for each value as a function of GA were constructed, using regression analysis. Distributions of Z-scores of all values based on GA were created to evaluate the fitness of models. Intraclass correlation coefficients were used to assess inter-/intraobserver variability.

RESULTS

A total of 395 fetuses were measured for anterior complex. All parameters changed with GA with quadratic function. The models for predicting means and standard deviation of the five parameters as well as percentile charts were created. All models were proven well-fitted. The intra-/interobserver reliability coefficients of all values showed excellent agreement.

CONCLUSION

The reference ranges of the fetal anterior complex, including VI, AW, and CSP, in axial transventricular and coronal transcaudate planes have been established and available for clinical use.

Development of the prosencephalic structures, ganglionic eminence, basal ganglia and thalamus at 11 + 3 to 13 + 6 gestational weeks on 3D transvaginal ultrasound including normative data

OBJECTIVES

To show the development of ganglionic eminence, basal ganglia and thalamus/hypothalamus in week 11 + 3 to 13 + 6 by transvaginal 3D ultrasound.

METHODS

To visualize the prosencephalic structures surrounding the 3rd ventricle, 285 three-dimensional ultrasound volume blocks from 402 fetuses examined were selected in a prospective transvaginal 3D study to compare ultrasound images of ganglionic eminence, basal ganglia, thalamus/hypothalamus with embryological sections. In addition, measurements of the described structures were made in 104 fetuses to quantify the embryological development.

RESULTS

The sonomorphologic characteristics of ganglionic eminence, basal ganglia and thalamus/hypothalamus are described in 71% of the fetuses examined. Measurements of the structures in 57% of the fetuses, show the following results: axGE ap = 0.17 + 0.112*CRL; axGE/I = 0.888 + 0.048*CRL; axGE/BG = 0.569 + 0.041*CRL; coGE/BG = 0.381 + 0.048*CRL; coTh lat = - 0.002 + 0.135*CRL; coTh/HyT = 3.68 + 0.059*CRL; co3.V lat = 0.54 + 0.008*CRL.

CONCLUSION

Transvaginal 3D neurosonography allows visualization and measurement of normal structures in the fetal prosencephalon at 11 + 3 to 13 + 6 weeks of gestation (GW) including details of ganglionic eminence (GE), basal ganglia (BG), and thalamus/hypothalamus (Th/HyT). Further scientific work is needed before using the results to decide on pathological changes in patients.

Obliterated cavum septi pellucidi: is it always a benign finding? A case report and narrative review of the literature

OBJECTIVE

The septum pellucidum is a virtual cavity located at the anterior part of the brain midline, which only in fetal life has a certain amount of fluid inside. The presence of an obliterated cavum septi pellucidi (oCSP) in the prenatal period is poorly described in the literature but, nevertheless, it constitutes an important clinical dilemma for the fetal medicine specialist in terms of significance and prognosis. Moreover, its occurrence is increasing maybe because of the widespread of high-resolution ultrasound machine. The aim of this work is to review the available literature regarding the oCSP along with the description of a case-report of oCSP with an unexpected outcome.

METHODS

A search of the literature through Pubmed was performed up to December 2022 with the aim to identify all cases of oCSP previously described, using as keywords "cavum septi pellucidi," "abnormal cavum septi pellucidi," "fetus," and "septum pellucidum." Along with the narrative review, we describe a case-report of oCSP.

RESULTS

A 39 years old woman was diagnosed with a nuchal translucency between the 95° and 99° centile in the first trimester and an oCSP and "hookshaped" gallbladder at 20 weeks. Left polymicrogyria was found at fetal magnetic resonance imaging (MRI). Standard karyotype and chromosomal microarray analysis (CMA) were normal. After birth, the newborn presented signs of severe acidosis, untreatable seizures and multiorgan failure leading to death. A targeted gene analysis of the epilepsy panel revealed the presence of a de novo pathogenic variant involving the PTEN gene. The literature review identified four articles reporting on the oCSP of which three were case report and one was a case-series. The reported rate of associated cerebral findings is around 20% and the rate of adverse neurological outcome is around 6%, which is higher than the background risk of the general population.

CONCLUSIONS

This case-report and review of the literature shows that oCSP is a clinical entity poorly described so far and that, despite the generally good prognosis, it requires caution in counseling. The diagnostic work-up should include neurosonography while fetal MRI may be always indicated for non-isolated cases only, depending on local facilities. Targeted gene analysis or whole exome sequencing may be indicated for non-isolated cases.

Prenatal ultrasound for the diagnosis of the agenesis of corpus callosum: a meta-analysis

BACKGROUND

Prenatal ultrasound has been regularly used as the screening tool for agenesis of corpus callosum (ACC) of the fetuses, which were mainly suspected on the basis of indirect signs rather than the visualization of the CC. However, the diagnostic accuracy of prenatal ultrasound for ACC, compared to the gold standard of postmortem diagnosis or postnatal images, is still unknown. This meta-analysis was performed to comprehensively evaluate the efficacy of prenatal ultrasound for the diagnosis of ACC.

METHODS

Studies evaluating the diagnostic accuracy of prenatal ultrasound for ACC compared to postmortem diagnosis or postnatal images were retrieved by searching PubMed, Embase, and Web of Science databases. Pooled sensitivity and specificity were calculated with a random-effects model. The diagnostic accuracy was measured by summarized area under the receiver operating characteristic (AUC) curve.

RESULTS

Twelve studies involving 544 fetuses with suspected anomalies of central nervous system were included, and 143 of them were with validated diagnosis of ACC. Pooled results showed that prenatal ultrasound has satisfying diagnostic efficacy for ACC, with the pooled sensitivity, specificity, positive and negative likelihood ratios of 0.72 (95% confidence interval [CI]: 0.39-0.91), 0.98 (95% CI: 0.79-1.00), 43.73 (95% CI: 3.42-558.74, and 0.29 (95% CI: 0.11-0.74), respectively. The pooled AUC was 0.94 (95% CI: 0.92-0.96), suggesting good diagnostic performance of prenatal ultrasound. Subgroup analysis according to the prenatal ultrasound procedures showed a better diagnostic efficacy of neurosonography than that of regular ultrasound screening (sensitivity: 0.84 versus 0.57, specificity: 0.98 versus 0.89, and AUC: 0.97 versus 0.78).

CONCLUSIONS

Prenatal ultrasound, particularly for the neurosonography, confers satisfying efficacy for the diagnosis of ACC.

Modeling fetal cortical development by quantile regression for gestational age and head circumference: a prospective cross sectional study

OBJECTIVES

To develop charts for fetal brain cortical structures following a proposed standardized methodology and using quantile regression.

METHODS

Prospective cross-sectional study including 344 low-risk singleton pregnancies between 19 and 34 weeks of gestation. The depth of Sylvian (SF), Parieto-occipital (POF) and Calcarine fissures (CF) were measured on ultrasound images using a standardized technique and their changes were evaluated by quantile regression as a function of gestational age (GA) interval or head circumference (HC).

RESULTS

The measurements of SF, POF and CF depth significantly increased with gestation. Linear models better described the changes of cortical variables with GA and HC. When the fit of sulci depth with GA and HC were compared, a close relationship was highlighted for the latter variable.

CONCLUSIONS

We provided prospective charts of fetal cortical development using quantile regression and following a strict standardized methodology These new charts may help in better identifying cases at higher risk of abnormal cortical neurodevelopment.

Tela-choroidea-to-anterior-cerebral-artery distance (TACAD): novel marker on color Doppler to identify fetuses with complete or partial agenesis of corpus callosum

OBJECTIVES

To assess objectively the course of the anterior cerebral artery (ACA) by measuring its distance to the tela choroidea in the midsagittal view, and to compare this distance in normal fetuses with that in those with agenesis of the corpus callosum (ACC), a condition known to be associated with an abnormal course of the ACA.

METHODS

The tela-choroidea-to-anterior-cerebral-artery distance (TACAD) was measured in the midsagittal view of the brain on color Doppler, between the anterior border of the tela choroidea and the ACA at the level of the callosal genu. Reference ranges in relation to gestational age were established in a prospective, cross-sectional study of 253 normal healthy fetuses between 19 and 36 weeks of gestation. The study group included fetuses with complete ACC (n = 28) or partial ACC (n = 18).

RESULTS

TACAD of normal fetuses showed an increase during the second half of pregnancy, with a mean value of 10.1 mm and 14.2 mm at 22 and 30 weeks of gestation, respectively. All (28/28) fetuses with complete ACC and 83% (15/18) of those with partial ACC had significantly shorter TACAD, with mean values of 3.9 mm and 6.6 mm, respectively.

CONCLUSIONS

TACAD is a measurement that is simple to obtain during fetal color Doppler neurosonography, which enables quantification of the course of the ACA and pericallosal artery. TACAD is shorter in fetuses with complete or partial ACC than in normal fetuses and provides an objective, quantifiable value, rather than merely descriptive information. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Prenatal exome sequencing analysis in fetuses with central nervous system anomalies

OBJECTIVE

To evaluate the utility of prenatal exome sequencing (pES) in fetuses with central nervous system (CNS) abnormalities.

METHODS

This was a retrospective cohort study of fetuses identified to have CNS abnormality on prenatal ultrasound and/or magnetic resonance imaging. All fetuses were first analyzed by chromosomal microarray analysis (CMA). Fetuses with a confirmed aneuploidy or causal pathogenic copy-number variant (CNV) on CMA did not undergo pES analysis and were excluded, while those with a negative CMA result were offered pES testing.

RESULTS

Of the 167 pregnancies included in the study, 42 (25.1%) were identified to have a pathogenic or likely pathogenic (P/LP) variant. The diagnostic rate was significantly higher in fetuses with a non-isolated CNS abnormality than in those with a single CNS abnormality (35.7% (20/56) vs 14.5% (8/55); P = 0.010). Moreover, when a fetus had three or more CNS abnormalities, the positive diagnostic rate increased to 42.9%. A total of 25/42 (59.5%) cases had de-novo mutations, while, in the remaining cases, mutations were inherited and carried a significant risk of recurrence. Families whose fetus carried a P/LP mutation were more likely to choose advanced pregnancy termination than those with a variant of uncertain significance, secondary/incidental finding or negative pES result (83.3% (25/30) vs 41.3% (38/92); P < 0.001).

CONCLUSION

pES improved the identification of genetic disorders in fetuses with CNS anomalies without a chromosomal abnormality or CNV identified on CMA, regardless of the number of CNS anomalies and presence of extracranial abnormality. We also demonstrated that pES findings can significantly impact parental decision-making. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Modeling fetal cavum septum pellucidi width by quantile regression at 18-34 weeks of gestation: A prospective cross-sectional study

OBJECTIVE

Develop charts for cavum septum pellucidi (CSP) following a standardized methodology and using quantile regression. The secondary objective was to assess the influence of fetal gender on the generated reference curves.

METHODS

In a cross-sectional prospective study 453 low-risk singleton pregnancies were evaluated at a gestational age interval between 18 and 34 weeks. The width of CSP were measured on ultrasound images using a standardized technique and their changes were evaluated by quantile regression as a function of gestational age (GA) interval or head circumference (HC). Differences between sex were evaluated.

RESULTS

The measurement of CSP significantly increased with gestation and HC. Linear models better described the changes of CSP with GA and HC. The fits of CSP width with GA and HC were not significantly different. Male fetuses showed significantly higher CSP width when compared to female fetuses (u = 2.973; p = 0.005).

CONCLUSIONS

We generated prospective nomograms of fetal CSP development using quantile regression and following a strict standardized methodology. These new charts may be useful to better identify abnormal cases at higher risk of associated anomalies. Further our findings underline the potential effect of gender in developing fetal brain.

Automatic biometry of fetal brain MRIs using deep and machine learning techniques

Linear biometric measurements on magnetic resonance images are important for the assessment of fetal brain development, which is expert knowledge dependent and laborious. This study aims to construct a segmentation-based method for automatic two-dimensional biometric measurements of fetal brain on magnetic resonance images that provides a fast and accurate measurement of fetal brain. A total of 268 volumes (5360 images) magnetic resonance images of normal fetuses were included. The automatic method involves two steps. First, the fetal brain was segmented into four parts with a deep segmentation network: cerebrum, cerebellum, and left and right lateral ventricles. Second, the measurement plane was determined, and the corresponding biometric parameters were calculated according to clinical guidelines, including cerebral biparietal diameter (CBPD), transverse cerebellar diameter (TCD), left and right atrial diameter (LAD/RAD). Pearson correlation coefficient and Bland-Altman plots were used to assess the correlation and agreement between computer-predicted values and manual measurements. Mean differences were used to evaluate the errors quantitatively. Analysis of fetal cerebral growth based on the automatic measurements was also displayed. The experiment results show that correlation coefficients for CBPD, TCD, LAD and RAD were as follows: 0.977, 0.990, 0.817, 0.719, mean differences were - 2.405 mm, - 0.008 mm, - 0.33 mm, - 0.213 mm, respectively. The correlation between the errors and gestational age was not statistically significant (p values were 0.2595, 0.0510, 0.1995, and 0.0609, respectively). The proposed automatic method for linear measurements on fetal brain MRI achieves excellent performance, which is expected to be applied in clinical practice and be helpful for prenatal diagnosis and clinical work efficiency improvement.

Deep learning system improved detection efficacy of fetal intracranial malformations in a randomized controlled trial

Congenital malformations of the central nervous system are among the most common major congenital malformations. Deep learning systems have come to the fore in prenatal diagnosis of congenital malformation, but the impact of deep learning-assisted detection of congenital intracranial malformations from fetal neurosonographic images has not been evaluated. Here we report a three-way crossover, randomized control trial (Trial Registration: ChiCTR2100048233) that assesses the efficacy of a deep learning system, the Prenatal Ultrasound Diagnosis Artificial Intelligence Conduct System (PAICS), in assisting fetal intracranial malformation detection. A total of 709 fetal neurosonographic images/videos are read interactively by 36 sonologists of different expertise levels in three reading modes: unassisted mode (without PAICS assistance), concurrent mode (using PAICS at the beginning of the assessment) and second mode (using PAICS after a fully unaided interpretation). Aided by PAICS, the average accuracy of the unassisted mode (73%) is increased by the concurrent mode (80%; P < 0.001) and the second mode (82%; P < 0.001). Correspondingly, the AUC is increased from 0.85 to 0.89 and to 0.90, respectively (P < 0.001 for all). The median read time per data is slightly increased in concurrent mode but substantially prolonged in the second mode, from 6 s to 7 s and to 11 s (P < 0.001 for all). In conclusion, PAICS in both concurrent and second modes has the potential to improve sonologists' performance in detecting fetal intracranial malformations from neurosonographic data. PAICS is more efficient when used concurrently for all readers.

Association of deep phenotyping with diagnostic yield of prenatal exome sequencing for fetal brain abnormalities

PURPOSE

To evaluate whether deep prenatal phenotyping of fetal brain abnormalities (FBAs) increases diagnostic yield of trio-exome sequencing (ES) compared with standard phenotyping.

METHODS

Retrospective exploratory analysis of a multicenter prenatal ES study. Participants were eligible if an FBA was diagnosed and subsequently found to have a normal microarray. Deep phenotyping was defined as phenotype based on targeted ultrasound plus prenatal/postnatal magnetic resonance imaging, autopsy, and/or known phenotypes of other affected family members. Standard phenotyping was based on targeted ultrasound alone. FBAs were categorized by major brain findings on prenatal ultrasound. Cases with positive ES results were compared with those that have negative results by available phenotyping, as well as diagnosed FBAs.

RESULTS

A total of 76 trios with FBAs were identified, of which 25 (33%) cases had positive ES results and 51 (67%) had negative results. Individual modalities of deep phenotyping were not associated with diagnostic ES results. The most common FBAs identified were posterior fossa anomalies and midline defects. Neural tube defects were significantly associated with receipt of a negative ES result (0% vs 22%, P = .01).

CONCLUSION

Deep phenotyping was not associated with increased diagnostic yield of ES for FBA in this small cohort. Neural tube defects were associated with negative ES results.

Fetal neurosurgery

Among fetal surgical procedures, neurosurgery stands out due to the number of cases and the possibility of developing new procedures that can be performed in the fetal period. To perform fetal neurosurgical procedures, there is a need for specialized centers that have experts in the diagnosis of fetal pathologies and a highly complex obstetrics service with specialized maternal-fetal teams associated with a pediatric neurosurgery center with expertise in the diverse pathologies of the fetus and the central nervous system that offers multidisciplinary follow-up during postnatal life. Services that do not have these characteristics should refer their patients to these centers to obtain better treatment results. It is essential that the fetal neurosurgical procedure be performed by a pediatric neurosurgeon with extensive experience, as he will be responsible for monitoring these patients in the postnatal period and for several years. The objective of this manuscript is to demonstrate the diagnostic and treatment possibilities, in the fetal period, of some neurosurgical diseases such as hydrocephalus, tumors, occipital encephalocele, and myelomeningocele.

Validation of an automatic software in assessing fetal brain volume from three dimensional ultrasonographic volumes: Comparison with manual analysis

OBJECTIVE

This study was aimed to test the agreement between a manual and an automatic technique in measuring fetal brain volume (FBV) from three-dimensional (3D) fetal head datasets.

METHODS

FBV were acquired independently by two operators from low risk singleton pregnancies at a gestational age between 19 and 34 weeks. FBV measurements were obtained using an automatic software (Smart ICV™) and manually by Virtual Organ Computer-aided AnaLysis (VOCAL™). Intraclass correlation coefficient (ICC) were calculated to assess reliability, while bias and agreement were evaluate by examining Bland-Altman plots. The time spent in measuring volumes was calculated and values obtained compared.

RESULTS

Sixty-three volumes were considered for the study. In all the included volumes successful volume analysis were obtained with both techniques. Smart ICV™ showed a high intra-observer (0.996; 95% CI 0.994-0.998) and inter-observer (ICC 0.995; 95% CI 0.991-0.997). An excellent degree of reliability was found when the two techniques were compared (ICC 0.995; 95% CI 0.987-0.998). The time required to perform FBV was significantly lower for Smart ICV™ than VOCAL™ (8.2 ± 4.5 vs. 121.3 ± 19.0 s; p < 0.0001).

CONCLUSIONS

The measurement of FBV is feasible with both manual and automatic techniques. Smart ICV™ showed an excellent intra- and inter-observer reliability associated with a valuable agreement with volume measurements obtained manually with VOCAL™. Volumes may be measured significantly faster with smart ICV™ than manually and this automatic software has the potential to become the preferred methods for the assessment of FBV.

Fetal neurosonography as accurate tool for diagnosis of brain involvement in tuberous sclerosis

OBJECTIVE

To demonstrate the potential utility of dedicated neurosonography for the diagnosis of fetal brain involvement in tuberous sclerosis complex.

METHODS

This was a multicenter retrospective study of fetuses at high risk for tuberous sclerosis complex. Dedicated neurosonographic, fetal magnetic resonance imaging (MRI) and postnatal reports were reviewed. Data collected included reason for referral, gestational age at which cardiac rhabdomyoma was first suspected and final number of cardiac rhabdomyomas detected on dedicated imaging. We searched for tuberous sclerosis complex-related brain involvement, defined as the presence of one or more of the following findings: white-matter lesions; subependymal nodules; cortical/subcortical tubers; and subependymal giant-cell astrocytoma.

RESULTS

We included 20 patients at high risk of tuberous sclerosis complex, of whom 19 were referred for the presence of cardiac rhabdomyomas and one for a deletion in chromosome 16 involving the tuberous sclerosis complex gene locus. Cardiac rhabdomyomas were diagnosed at a mean gestational age of 27 + 2 weeks (range, 16 + 0 to 36 + 3 weeks) and the mean number of cardiac rhabdomyomas per patient was 4 (range, 1-10). Brain involvement was present in 15 fetuses, in 13 of which the disease was confirmed in one or more of the following ways: chromosomal microarray analysis (n = 1), exome sequencing (n = 7), autopsy (n = 4), clinical tuberous sclerosis complex in the newborn (n = 4) and a sibling diagnosed with clinical tuberous sclerosis complex (n = 1). In two cases, the disease could not be confirmed: one was lost to follow-up and autopsy, following termination of pregnancy, was not performed in the other. Among the five cases without brain findings, tuberous sclerosis complex was confirmed in three by exome sequencing (n = 2) and/or autopsy findings (n = 2). The two remaining cases had normal exome sequencing; one case had five cardiac rhabdomyomas, which was a highly suggestive finding, while in the final case, the autopsy was considered normal, representing the only false-positive case in our cohort.

CONCLUSIONS

Contrary to current literature, dedicated neurosonography appears to be effective in the diagnosis of brain involvement in fetuses at risk of tuberous sclerosis complex and should be used as the first-line approach. Although the number of cases in which MRI was performed was small, it seems that, in the presence of ultrasound findings, the added value of MRI is low. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Midline suprapineal pseudocyst in brain of fetuses with open spina bifida

OBJECTIVES

Recently, it was noted that fetuses with open spina bifida (OSB) may have a midline cystic structure evident on ultrasound. Our aims were to determine the prevalence of this cystic structure, shed light on its pathophysiology and investigate the association between its presence and other characteristic brain findings in fetuses with OSB.

METHODS

This was a single-center retrospective study of all fetuses with OSB and available cineloop images in the axial plane referred to the Ontario Fetal Centre, Toronto, Canada, between June 2017 and May 2022. Ultrasound and magnetic resonance imaging (MRI) data obtained between 18 + 0 and 25 + 6 weeks were reviewed in search of a midline cystic structure. Pregnancy and lesion characteristics were collected. Transcerebellar diameter (TCD), clivus-supraocciput angle (CSA) and additional brain abnormalities (abnormal cavum septi pellucidi (CSP), abnormal corpus callosum (CC) and periventricular nodular heterotopia (PNH)) were assessed. In cases of in-utero repair, imaging findings were reviewed postoperatively. In cases of termination, neuropathological findings were reviewed, if available.

RESULTS

Of 76 fetuses with OSB, 56 (73.7%) had a suprapineal cystic structure on ultrasound. The percentage of agreement between ultrasound and MRI detection was 91.5% (Cohen's kappa coefficient, 0.78 (95% CI, 0.57-0.98)). Brain autopsy in terminated cases revealed a dilatation of the posterior third ventricle, with redundant tela choroidea and arachnoid forming the membranous roof of the third ventricle, anterior and superior to the pineal gland. A cyst wall could not be identified, indicating that the structure was a pseudocyst. The presence of the pseudocyst was associated with a smaller CSA (pseudocyst absent, 62.11 ± 9.60° vs pseudocyst present, 52.71 ± 8.22°; P = 0.04). When the pseudocyst was present, its area was correlated inversely with TCD (r, -0.28 (95% CI, -0.51 to -0.02); P = 0.04). Fetal surgery did not have any impact on the growth rate of the pseudocyst (fetal surgery, 5.07 ± 3.29 mm2 /week vs expectant management, 4.35 ± 3.17 mm2 /week; P = 0.58). The presence of the pseudocyst was not associated with abnormal CSP, CC or presence of PNH. None of the cases with available postnatal follow-up required surgical procedure related to the pseudocyst.

CONCLUSIONS

Approximately 75% of all OSB cases have a suprapineal pseudocyst. Its presence is associated with the degree of hindbrain herniation but not with abnormalities of the CSP and CC or presence of PNH. Thus, it should not be regarded as additional brain pathology and should not preclude fetuses from undergoing fetal surgery for OSB. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Alcohol exposure before and during pregnancy is associated with reduced fetal growth: the Safe Passage Study

BACKGROUND

Prenatal alcohol exposure (PAE) is a worldwide public health concern. While PAE is known to be associated with low birth weight, little is known about timing and quantity of PAE on fetal growth. This study investigated the association between periconceptional and prenatal alcohol exposure and longitudinal fetal growth, focusing on timing and quantity in a high exposure cohort.

METHODS

The Safe Passage Study was a prospective cohort study, including 1698 pregnant women. Two-dimensional transabdominal ultrasound examinations were performed to measure fetal femur length, abdominal and head circumference, and biparietal diameter, at three time points during pregnancy. Estimated fetal weight and Z-scores of all parameters were calculated. Trimester-specific alcohol exposure was assessed using the Timeline Followback method. To investigate the associations of specific timing of PAE and fetal growth, two models were built. One with alcohol exposure as accumulative parameter over the course of pregnancy and one trimester specific model, in which PAE was separately analyzed. Linear mixed models adjusted for potential confounders were applied with repeated assessments of both alcohol exposure and fetal growth outcomes.

RESULTS

This study demonstrated that periconceptional and prenatal alcohol exposure were associated with reduced fetal growth. Effect sizes are displayed as estimated differences (ED) in Z-score and corresponding 95% confidence intervals (95% CIs). When investigated as accumulative parameter, PAE was related to a smaller femur length (ED30; - 0.13 (95% CI; - 0.22; - 0.04), ED36; - 0.14 (95% CI; - 0.25; - 0.04)) and a smaller abdominal circumference (ED36; - 0.09 (95% CI; - 0.18; - 0.01)). Periconceptional alcohol exposure was associated with a smaller abdominal circumference (ED30; - 0.14 (95% CI; - 0.25; - 0.02), ED36; - 0.22 (95% CI; - 0.37; - 0.06)) and a smaller estimated fetal weight (ED36; - 0.22 (95% CI; - 0.38; - 0.05)). Second trimester alcohol exposure was associated with a smaller abdominal circumference (ED30; - 0.49 (95% CI; - 0.86; - 0.12), ED36; - 0.70 (95% CI; - 1.22; - 0.17)) and estimated fetal weight (ED30; - 0.54 (95% CI; - 0.94; - 0.14), ED36; - 0.69 (95% CI; - 1.25; - 0.14)). No additional association of binge drinking was found besides the already observed association of PAE and fetal growth.

CONCLUSIONS

This study demonstrated that PAE negatively affects fetal growth, in particular when exposed during the periconception period or in second trimester. Our results indicate that potential negative consequences of PAE are detectable already before birth. Therefore, healthcare providers should actively address and discourage alcohol use during pregnancy.

A Clinical Approach to Semiautomated Three-Dimensional Fetal Brain Biometry-Comparing the Strengths and Weaknesses of Two Diagnostic Tools: 5DCNS+TM and SonoCNSTM

(1) Objective: We aimed to evaluate the accuracy and efficacy of AI-assisted biometric measurements of the fetal central nervous system (CNS) by comparing two semiautomatic postprocessing tools. We further aimed to discuss the additional value of semiautomatically generated sagittal and coronal planes of the CNS. (2) Methods: Three-dimensional (3D) volumes were analyzed with two semiautomatic software tools, 5DCNS+™ and SonoCNS™. The application of 5DCNS+™ results in nine planes (axial, coronal and sagittal) displayed in a single template; SonoCNS™ depicts three axial cutting sections. The tools were compared regarding automatic biometric measurement accuracy. (3) Results: A total of 129 fetuses were included for final analysis. Our data indicate that, in terms of the biometric quantification of head circumference (HC), biparietal diameter (BPD), transcerebellar diameter (TCD) and cisterna magna (CM), the accuracy of SonoCNS™ was higher with respect to the manual measurement of an experienced examiner compared to 5DCNS+™, whereas it was the other way around regarding the diameter of the posterior horn of the lateral ventricle (Vp). The inclusion of four orthogonal coronal views in 5DCNS+™ gives valuable information regarding spatial arrangements, particularly of midline structures. (4) Conclusions: Both tools were able to ease assessment of the intracranial anatomy, highlighting the additional value of automated algorithms in clinical use. SonoCNS™ showed a superior accuracy of plane reconstruction and biometry, but volume reconstruction using 5DCNS+™ provided more detailed information, which is needed for an entire neurosonogram as suggested by international guidelines.

Automatic Deep Learning-Based Pipeline for Automatic Delineation and Measurement of Fetal Brain Structures in Routine Mid-Trimester Ultrasound Images

INTRODUCTION

The aim of this study was to develop a pipeline using state-of-the-art deep learning methods to automatically delineate and measure several of the most important brain structures in fetal brain ultrasound (US) images.

METHODS

The dataset was composed of 5,331 images of the fetal brain acquired during the routine mid-trimester US scan. Our proposed pipeline automatically performs the following three steps: brain plane classification (transventricular, transthalamic, or transcerebellar plane); brain structures delineation (9 different structures); and automatic measurement (from the structure delineations). The methods were trained on a subset of 4,331 images and each step was evaluated on the remaining 1,000 images.

RESULTS

Plane classification reached 98.6% average class accuracy. Brain structure delineation obtained an average pixel accuracy higher than 96% and a Jaccard index higher than 70%. Automatic measurements get an absolute error below 3.5% for the four standard head biometries (head circumference, biparietal diameter, occipitofrontal diameter, and cephalic index), 9% for transcerebellar diameter, 12% for cavum septi pellucidi ratio, and 26% for Sylvian fissure operculization degree.

CONCLUSIONS

The proposed pipeline shows the potential of deep learning methods to delineate fetal head and brain structures and obtain automatic measures of each anatomical standard plane acquired during routine fetal US examination.

Use of artificial intelligence and deep learning in fetal ultrasound imaging

Deep learning is considered the leading artificial intelligence tool in image analysis in general. Deep-learning algorithms excel at image recognition, which makes them valuable in medical imaging. Obstetric ultrasound has become the gold standard imaging modality for detection and diagnosis of fetal malformations. However, ultrasound relies heavily on the operator's experience, making it unreliable in inexperienced hands. Several studies have proposed the use of deep-learning models as a tool to support sonographers, in an attempt to overcome these problems inherent to ultrasound. Deep learning has many clinical applications in the field of fetal imaging, including identification of normal and abnormal fetal anatomy and measurement of fetal biometry. In this Review, we provide a comprehensive explanation of the fundamentals of deep learning in fetal imaging, with particular focus on its clinical applicability. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Directive clinique no 440 : Prise en charge de la grossesse gémellaire monochoriale

OBJECTIF

Cette directive clinique passe en revue les données probantes sur la prise en charge de la grossesse gémellaire monochoriale normale et compliquée.

POPULATION CIBLE

Les femmes menant une grossesse gémellaire ou multiple de haut rang. BéNéFICES, RISQUES ET COûTS: L'application des recommandations de cette directive devrait améliorer la prise en charge des grossesses gémellaires (ou multiples de haut rang) monochoriales compliquées et non compliquées. Ces recommandations aideront les fournisseurs de soins à surveiller adéquatement les grossesses gémellaires monochoriales ainsi qu'à détecter et prendre en charge rapidement les complications associées de façon optimale afin de réduire les risques de morbidité et mortalité périnatales. Ces recommandations impliquent une surveillance échographique plus fréquente en cas de grossesse monochoriale qu'en cas de grossesse bichoriale. DONNéES PROBANTES: La littérature publiée a été colligée par des recherches dans les bases de données PubMed et Cochrane Library au moyen de termes MeSH pertinents (Twins, Monozygotic; Ultrasonography, Prenatal; Placenta; Fetofetal Transfusion; Fetal Death; Fetal Growth Retardation). Les résultats ont été restreints aux revues systématiques, aux essais cliniques randomisés et aux études observationnelles. Aucune date limite n'a été appliquée, mais les résultats ont été limités aux contenus en anglais ou en français. MéTHODES DE VALIDATION: Les auteurs principaux ont rédigé le contenu et les recommandations et ils se sont entendus sur ces derniers. Le conseil d'administration de la SOGC a approuvé la version définitive aux fins de publication. Les auteurs ont évalué la qualité des données probantes et la force des recommandations en utilisant le cadre méthodologique GRADE (Grading of Recommendations Assessment, Development and Evaluation). Voir l'annexe A en ligne (tableau A1 pour les définitions et tableau A2 pour l'interprétation des recommandations fortes et conditionnelles [faibles]). PROFESSIONNELS CONCERNéS: Spécialistes en médecine fœto-maternelle, obstétriciens, radiologues, échographistes, médecins de famille, infirmières, sages-femmes, résidents et autres fournisseurs de soins de santé qui s'occupent de femmes menant une grossesse gémellaire ou multiple de haut rang. RéSUMé POUR TWITTER: Directive canadienne (SOGC) pour le diagnostic, la surveillance échographique et la prise en charge des complications de la grossesse gémellaire monochoriale (p. ex., STT, TAPS, retard de croissance sélectif, cojumeau acardiaque, monoamnionicité et mort d'un jumeau). DÉCLARATIONS SOMMAIRES: RECOMMANDATIONS.

Corpus callosal reference ranges: systematic review of methodology of biometric chart construction and measurements obtained

OBJECTIVE

Adequate reference ranges of size of the corpus callosum (CC) are necessary to improve characterization of CC abnormalities and parental counseling. The objective of this study was to evaluate the methodology used in studies developing references charts for CC biometry.

METHODS

We conducted a systematic review of studies on fetal CC biometry using a set of predefined quality criteria of study design, statistical analysis and reporting methods. We included observational studies whose primary aim was to create ultrasound or magnetic resonance imaging charts for CC size in a normal population of fetuses. Studies were scored against a predefined set of independently agreed methodological criteria, and an overall quality score was given for each study.

RESULTS

Twelve studies met the inclusion criteria. Quality scores ranged between 17.4% and 95.7%. The greatest potential for bias was noted for the following items: sample selection and sample-size calculation, as only 17% of the studies were population-based and had consecutive or random recruitment of patients and with a justification of the sample size; number of measurements obtained for CC biometry, as only 17% of the studies performed more than one measurement per fetus and per scan; and description of characteristics of the study population, as only 8% of the studies clearly reported a minimum dataset of demographic characteristics.

CONCLUSIONS

Our review demonstrates substantial heterogeneity in methods and final biometric values of the fetal CC across the evaluated studies. The use of uniform methodology of the highest quality is essential in order to define a 'short' CC and provide appropriate parental counseling. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

First-trimester choroid-plexus-to-lateral-ventricle disproportion and prediction of subsequent ventriculomegaly

OBJECTIVE

Ventriculomegaly can be associated with long-term neurodevelopmental impairment. Prenatal diagnosis of ventriculomegaly is most commonly made at the routine second-trimester anomaly scan. The value of first-trimester ultrasound has expanded to early diagnosis and screening of fetal abnormalities. The objective of this study was to assess the predictive accuracy of first-trimester choroid-plexus-to-lateral-ventricle-or-head ratios for development of ventriculomegaly at a later gestational age.

METHODS

This was a case-control study of fetuses with isolated ventriculomegaly diagnosed after 16 weeks' gestation and a control group of normal fetuses (without ventriculomegaly). The exclusion criteria included aneuploidy, genetic syndrome and/or other brain abnormality. Stored two-dimensional first-trimester ultrasound images were analyzed blindly offline and fetal biometry was performed in the axial view of the fetal head. The ratios of choroid plexus area (PA) to lateral ventricular area (VA), choroid plexus length (PL) to lateral ventricular length (VL), choroid plexus diameter (PD) to lateral ventricular diameter (VD) and PA to biparietal diameter (BPD) were measured at 11 + 0 to 13 + 6 weeks' gestation. Intra- and interobserver variability of measurement of these fetal head biometric parameters at 11 + 0 to 13 + 6 weeks' gestation were assessed in 20 normal fetuses using intraclass correlation coefficients with 95% CI. The accuracy of first-trimester biometric measurements for prediction of ventriculomegaly was assessed using the area under the receiver-operating-characteristics curves (AUC).

RESULTS

The analysis included 683 singleton pregnancies, of which 102 fetuses were diagnosed with ventriculomegaly. Ventriculomegaly was mild in 86 (84.3%) cases and severe in the other 16 (15.7%). All first-trimester fetal choroid-plexus-to-lateral-ventricle/head ratios were significantly lower in cases with ventriculomegaly compared with controls (P < 0.001), with good inter- and intraobserver agreement (≥ 0.95) for the majority of the fetal head biometric parameters assessed. On adjusting for crown-rump length, optimism-adjusted AUC values obtained after cross-validation showed that both PL/VL ratio (AUC, 0.87 (95% CI, 0.73-0.98)) and PA/VA ratio (AUC, 0.90 (95% CI, 0.82-0.98)) had good predictive accuracy for severe ventriculomegaly. The PA/BPD ratio (AUC, 0.73 (95% CI, 0.54-0.90)) had modest predictive ability, which was significantly lower compared with that of the PA/VA ratio and PL/VL ratio (P = 0.003 and P = 0.001, respectively). The predictive accuracy of PD/VD ratio was low with an AUC of 0.65 (95% CI, 0.47-0.84). Optimism-adjusted AUC values obtained after cross-validation showed that PA/VA ratio offered the highest predictive accuracy for mild ventriculomegaly with an AUC of 0.84 (95% CI, 0.79-0.89), followed by PL/VL ratio (AUC, 0.82 (95% CI, 0.76-0.88)), PA/BPD ratio (AUC, 0.76 (95% CI, 0.69-0.82)) and PD/VD ratio (AUC, 0.75 (95% CI, 0.67-0.81)). Calibration plots showed that both PA/VA and PL/VL ratios had good calibration.

CONCLUSION

First-trimester prediction of ventriculomegaly using ratios of fetal choroid plexus to lateral ventricle/head appears promising. Future prospective studies are needed to validate the predictive accuracy of these ultrasound markers as a screening tool for ventriculomegaly. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.