Accuracy of neurosonography and MRI in clinical management of fetuses referred with central nervous system abnormalities

Follow-up outcome analysis of 324 cases of early-onset and late-onset mild fetal ventriculomegaly: a retrospective cohort study

BACKGROUND

Mild fetal ventriculomegaly (VM) is a nonspecific finding common to several pathologies with varying prognosis and is, therefore, a challenge in fetal consultation. We aimed to perform a constant, detailed analysis of prenatal findings and postnatal outcomes in fetuses with early-onset and late-onset mild ventriculomegaly, and provide a new evidence basis and new perspective for prenatal counseling.

METHODS

This is a retrospective cohort study of women with a diagnosis of mild fetal VM between January 2018 and October 2020. The population was divided into two groups according to the gestational ages (GAs) at initial diagnosis: the early-onset group (diagnosed at/before 24+6 weeks) and the late-onset group (diagnosed after 24+6 weeks). Clinical data and pregnancy outcomes were obtained from hospital records. The children's neurodevelopment status was assessed using the Ages and Stages Questionnaire, Third Edition (ASQ-3) and telephone interviews.

RESULTS

Our study cohort comprised 324 fetuses, out of which 94 (29%) were classified as early-onset group and 230 (71%) late-onset group. Early-onset group was more likely to have concurrent additional abnormalities, whereas in the late-onset group, isolated enlargement was more common (P = 0.01). Unilateral enlargement was more common in the late-onset group (P = 0.05), and symmetrical enlargement in the early-onset group (P < 0.01). In addition, early-onset mild VM cases were more likely to have intrauterine progression (P = 0.03), and many had a higher proportion of complex multisystem abnormalities. Compared with the late-onset group, the early-onset group was more often associated with congenital brain structure malformations. Approximately 11% of fetuses with mild VM had postnatal neurodevelopmental delay/disorders, and the risk was higher in the early-onset group (19.4% vs. 7.4%). Regression analysis showed that the GA at first diagnosis, non-isolated, and intrauterine progression significantly correlated with neurodevelopmental abnormalities.

CONCLUSIONS

Early-onset and late-onset mild VM had significantly different ultrasound features and outcomes. Early-onset mild VM may have more complex potential abnormalities and are more likely to predict poor prognosis than the late-onset.

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.

Postmortem MR in termination of pregnancy for central nervous system (CNS) anomalies

OBJECTIVES

To evaluate the concordance of conventional autopsy (CA) and postmortem magnetic resonance (MR) after termination of pregnancy (TOP) in fetuses with prenatally detected central nervous system (CNS) anomalies. Second, to determine the most informative postmortem investigation in parental counseling.

METHODS

All TOPs between 2006 and 2016 with prenatally detected CNS involvement and having a postmortem MR and CA as postmortem examinations were retrospectively analyzed and concordance levels were established.

RESULTS

Of 764 TOPs, 255 cases had a CNS anomaly detected prenatally (33.4%). Fetal genetic anomalies (n = 40) and cases without both postmortem MR and CA were excluded, leaving 68 cases for analysis.Disagreement between postmortem MR and CA was observed in 22 cases (32.4%). In eight cases (11.8%), more information was obtained by CA compared with MR. However, only two cases with major additional findings were found when compared with prenatal diagnosis. In 14 cases (20.6%), MR was superior to CA either because of additional cerebral anomalies undetected by CA (n = 5) and/or because of severe autolysis hindering pathology of the CNS (n = 9).

CONCLUSIONS

Our data point out that an adequate postmortem evaluation, valuable in parental counseling, can be provided by a postmortem MR in 97% of the cases.Key PointsAn adequate postmortem evaluation, valuable in parental counseling, can be provided by a postmortem (PM) magnetic resonance (MR) in the majority of cases.PM MR is an excellent postmortem imaging tool for the brain.In cases with brain autolysis, PM MR is often the only informative PM investigation tool.PM MR is an essential adjunct to CA in the PM evaluation of pregnancies terminated for a central nervous system (CNS) anomaly.

Fetal macrocephaly: Pathophysiology, prenatal diagnosis and management

Macrocephaly means a large head and is defined as a head circumference (HC) above the 98th percentile or greater than +2SD above the mean for gestational age. Macrocephaly can be primary and due to increased brain tissue (megalocephaly), which in most cases is familial and benign or secondary. The latter may be due to various causes, including but not limited to communicating or non-communicating hydrocephalus, cerebral edema, focal and pericerebral increased fluid collections, thickened calvarium and brain tumors. Megalocephaly can be syndromic or non-syndromic. In the former, gyral and structural CNS anomalies are common. It is important to exercise caution when considering a diagnosis of megalocephaly due to limitations in the accuracy of HC measurement, lack of nomograms for specific populations, inconsistencies between prenatal and postnatal HC growth curves and progression over time. The degree of macrocephaly is important, with mild macrocephaly ≤2.5SD carrying a good prognosis, especially when one of the parents has macrocephaly and normal development. Cases in which the patient history and/or physical exam are positive or when parental HC are normal are more worrisome and warrant a neurosonogram, fetal MRI and genetic testing to better delineate the underlying etiology and provide appropriate counseling.

Prenatal Neurological Diagnosis: Challenges in Neuroimaging, Prognostic Counseling, and Prediction of Neurodevelopmental Outcomes

Prenatal diagnosis of fetal brain abnormalities is rapidly evolving with the advancement of neuroimaging techniques, thus adding value to prognostic counseling and perinatal management. However, challenges and uncertainties persist in prenatal counseling due to limitations of prenatal imaging, continued development and maturation of the brain structure, and the heterogeneity and paucity of outcome studies. This topical review of fetal neurological consultations highlights prenatally diagnosed brain abnormalities that challenged prognostic counseling and perinatal management. Representative cases across multiple centers that highlighted diagnostic challenges were selected. Charts were reviewed for neuroimaging, genetic evaluation, prenatal prognostic discussion, postnatal imaging and testing, and infant outcome. We present case studies with prenatal and postnatal information discussing prenatal testing, fetal MRI interpretation, and complexities in the prognostic counseling process. Advocating for large-scale multicenter studies and a national collaborative fetal neurological registry to help guide the ever-expanding world of prenatal diagnostics and prognostic counseling is critical to this field. Study of large-scale outcomes data from such a registry can better guide fetal neurological consultations and facilitate comprehensive multidisciplinary planning and program development for educational curriculum for fetal-neonatal neurology.

Institutional Evaluation of Fetal Neurology Consults and Postnatal Outcomes: A 10-Year Retrospective Cohort Review

Background and Objectives

An increasing number of centers are offering fetal neurology consultation services; however, there is limited information available in overall institutional experiences. Data are lacking on the fetal characteristics, pregnancy course, and the influence of fetal consultation on perinatal outcomes. The aim of this study is to provide insight on the institutional fetal neurology consult process and areas of strengths and weaknesses.

Methods

We performed a retrospective electronic chart review of fetal consults from April 2, 2009, to August 8, 2019, at Nationwide Children's Hospital. The objectives were to summarize clinical characteristics, agreement of prenatal and postnatal diagnoses based on best available imaging, and postnatal outcomes.

Results

Of the 174 maternal-fetal neurology consults placed, 130 qualified for inclusion based on data available for review. Of the 131 anticipated fetuses, 5 experienced fetal demise, 7 underwent elective termination, and 10 died in the postnatal period. The majority were admitted to the neonatal intensive care unit; 34 (31%) required supportive intervention for feeding, breathing, or hydrocephalus, and 10 (8%) experienced seizures during their neonatal intensive care unit (NICU) stay. Imaging results from 113 babies who had prenatal and postnatal imaging of the brain were analyzed based on the primary diagnosis. The most common malformations were as follows (prenatal % vs postnatal %): midline anomalies (37% vs 29%), posterior fossa abnormalities (26% vs 18%), and ventriculomegaly (14% vs 8%). Additional disorders of neuronal migration were not seen on fetal imaging but were present in 9% of the postnatal studies. Analysis of agreement between prenatal and postnatal diagnostic imaging for the 95 babies who had MRIs at both time points found moderate concordance (Cohen kappa: 0.62, 95% CI 0.5-0.73; percent agreement: 69%, 95% CI 60%-78%). Consult recommendations for neonatal blood tests affected postnatal care in 64 of 73 cases in which the infant survived and data were available.

Discussion

Establishing a multidisciplinary fetal clinic can provide timely counseling and create rapport with families to have continuity of care for birth planning and postnatal management. Prognosis based on radiographic prenatal diagnosis requires caution as some neonatal outcomes may vary considerably.

Applicability of a semiautomated volumetric approach (5D CNS+™) for detailed antenatal reconstruction of abnormal fetal CNS anatomy

BACKGROUND

The aim of this study was to evaluate the accuracy and reliability of a semiautomated volumetric approach (5D CNS+™) when examining fetuses with an apparent abnormal anatomy of the central nervous system (CNS).

METHODS

Stored 3D volumes extracted from a cohort of > 1.400 consecutive 2nd and 3rd trimester pregnancies (range 15-36 gestational weeks) were analyzed using the semiautomatic software tool 5D CNS+™, enabling detailed reconstruction of nine diagnostic planes of the fetal brain. All 3D data sets were examined and judged for plane accuracy, the need for manual adjustment, and fetal CNS anomalies affecting successful plane reconstruction.

RESULTS

Based on our data of 91 fetuses with structural cerebral anomalies, we were able to reveal details of a wide range of CNS anomalies with application of the 5D CNS+™ technique. The corresponding anatomical features and consecutive changes of neighboring structures could be clearly demonstrated. Thus, a profound assessment of the entire altered CNS anatomy could be achieved in nearly all cases. The comparison with matched controls showed a significant difference in volume acquisition (p < 0.001) and in need for manual adjustment (p < 0.001) but not in the drop-out rates (p = 0.677) of both groups.

CONCLUSION

5D CNS+™ is applicable in the majority of cases with brain lesions and constitutes a reliable tool even if the integrity of the fetal CNS is compromised by structural anomalies. Using volume data that were acquired in identical cutting sections needed for conventional biometry allows for detailed anatomic surveys grossly independent of the examiner's experience.

Genomic architecture of fetal central nervous system anomalies using whole-genome sequencing

Structural anomalies of the central nervous system (CNS) are one of the most common fetal anomalies found during prenatal imaging. However, the genomic architecture of prenatal imaging phenotypes has not yet been systematically studied in a large cohort. Patients diagnosed with fetal CNS anomalies were identified from medical records and images. Fetal samples were subjected to low-pass and deep whole-genome sequencing (WGS) for aneuploid, copy number variation (CNV), single-nucleotide variant (SNV, including insertions/deletions (indels)), and small CNV identification. The clinical significance of variants was interpreted based on a candidate gene list constructed from ultrasound phenotypes. In total, 162 fetuses with 11 common CNS anomalies were enrolled in this study. Primary diagnosis was achieved in 62 cases, with an overall diagnostic rate of 38.3%. Causative variants included 18 aneuploids, 17 CNVs, three small CNVs, and 24 SNVs. Among the 24 SNVs, 15 were novel mutations not reported previously. Furthermore, 29 key genes of diagnostic variants and critical genes of pathogenic CNVs were identified, including five recurrent genes: i.e., TUBA1A, KAT6B, CC2D2A, PDHA1, and NF1. Diagnostic variants were present in 34 (70.8%) out of 48 fetuses with both CNS and non-CNS malformations, and in 28 (24.6%) out of 114 fetuses with CNS anomalies only. Hypoplasia of the cerebellum (including the cerebellar vermis) and holoprosencephaly had the highest primary diagnosis yields (>70%), while only four (11.8%) out of 34 neural tube defects achieved genetic diagnosis. Compared with the control group, rare singleton loss-of-function variants (SLoFVs) were significantly accumulated in the patient cohort.

Fetal brain imaging: A comparison between fetal ultrasonography and intra uterine magnetic resonance imaging (a systematic review and meta-analysis)

OBJECTIVE

The aim of this study was to compare ultrasound (US) and intra uterine MRI (IUMRI) of the brain in the diagnosis of fetal brain abnormalities.

METHODS

The present systematic review is done based on guidelines for preferred reporting items for systematic reviews and meta-analysis. All major articles comparing fetal US with IUMRI in fetuses with suspected brain abnormalities were qualified. Articles published before 2010 were excluded from the study. An I²  > 20% was considered as a sign of significant change. The statistical analysis was done using STATA -15 and Meta-Disk 1.4 applications.

RESULTS

Five articles were considered for meta-analysis. The sensitivity of US and IUMRI in diagnosing fetal abnormalities were 86% and 95%, respectively. The corresponding rates for specificity were 77% and 80%. IUMRI and US were concordant in 72.5% (95% CI: 68%-77%) of diagnoses. However, IUMRI added information in 21.7% of cases, while US added value was only 1.48.

CONCLUSION

Our results approved the good diagnostic performance of both US and IUMRI in confirming fetal brain normal development and emphasized that US is an appropriate screening technique in pregnancy. In cases of detected abnormalities in US, IUMRI is suggested as it was the most accurate imaging method and added information about the diagnosis in 22.2% of cases.

Developmental Brain Asymmetry. The Good and the Bad Sides

Brain asymmetry is a hallmark of the human brain. Recent studies report a certain degree of abnormal asymmetry of brain lateralization between left and right brain hemispheres can be associated with many neuropsychiatric conditions. In this regard, some questions need answers. First, the accelerated brain asymmetry is programmed during the pre-natal period that can be called “accelerated brain decline clock”. Second, can we find the right biomarkers to predict these changes? Moreover, can we establish the dynamics of these changes in order to identify the right time window for proper interventions that can reverse or limit the neurological decline? To find answers to these questions, we performed a systematic online search for the last 10 years in databases using keywords. Conclusion: we need to establish the right in vitro model that meets human conditions as much as possible. New biomarkers are necessary to establish the “good” or the “bad” borders of brain asymmetry at the epigenetic and functional level as early as possible.

The Role of Fetal Brain Magnetic Resonance Imaging in Current Fetal Medicine

In open spina bifida we studied the use of MRI for the assessment of the posterior fossa and prevalence of supratentorial anomalies before and after in utero repair. New postprocessing techniques were applied to evaluate fetal brain development in this population compared to controls. In fetuses with congenital diaphragmatic hernia, we evaluated the brain development in comparison to controls. Diffusion weighted imaging was applied to study difference between fetuses with proven first trimester cytomegalovirus infection and controls. Finally, we investigated the value of third trimester fetal brain MRI after treatment for complicated monochorionic diamniotic pregnancies.

Fetal brain MRI: how it added to ultrasound diagnosis of fetal CNS anomalies-1 year experience

Background

Central nervous system (CNS) anomalies are the most commonly diagnosed abnormalities of all fetal malformations and are usually primarily discovered on routine prenatal ultrasonography (US). Fetal magnetic resonance imaging (MRI) is a non-invasive technology with high soft tissue contrast that is documented to increase the diagnostic accuracy for detection of fetal brain anomalies.

The aim of our study is to analyze the value of adding magnetic resonance imaging (MRI) of the fetal brain to antenatal ultrasound in the diagnosis of fetal central nervous system (CNS) anomalies.

Results

We diagnosed various CNS anomalies including twelve cases with infra- and supra-tentorial arachnoid cysts, six cases had Dandy-Walker malformation (DWM) and its variants, 1 case with mega cisterna magna, 2 cases of holoprosencephaly, 1 case of hydranencephaly, 2 cases with supratentorial hydrocephalus, 1 case of craniopharyngioma, 6 cases with corpus callosum (CC) agenesis, 1 case of extradural hematoma, and 8 cases with Meckel-Gruber syndrome (MGS). MRI diagnosis confirmed the ultrasound finding, without additional information in 23 cases (57.5%%), added an extra finding in 11 cases (27.5%), differentiated between 2 pathologies in 3 cases (7.5%), and changed the diagnosis in 3 cases (7.5 %).

The 40 pregnancies resulted in 27 births (67.5%), 2 died directly after birth (5%), 7 terminations (17.5%), and 4 intrauterine fetal deaths (IUFD) (10 %).

Conclusion

Ultrasound is the gold standard imaging modality for anomaly scan in the second and third trimesters; however, MRI of the fetal brain might be a clinically valuable complement especially when ultrasound examination is inconclusive due to maternal obesity, severe oligohydramnios, or in complicated cases with unclear diagnosis.

Imaging diagnosis and legal implications of brain injury in survivors following single intrauterine fetal demise from monochorionic twins - a review of the literature

Brain injury of the surviving twin from monochorionic pregnancies following intrauterine fetal demise during the second and third trimesters is a rare but severe complication. Monochorionicity and gestational age at the time of stillbirth seem to be decisive factors in terms of long-term neurologic outcome prediction for the survivor. Magnetic resonance imaging (MRI), diffusion weighted imaging (DWI) in particular, seem to bring the earliest and most accurate diagnosis. Ultrasound detection of brain damage is possible in later stages of fetal brain injury. It is essential to provide early diagnosis and multidisciplinary counsel to the parents to ensure informed decision making. For couples who choose to terminate pregnancy legislation related to late abortion might lead to further distress. Our paper aims to stress the importance of MRI DWI in the evaluation of surviving twins following single intrauterine fetal demise in monochorionic pregnancies and the delicate context of the medical professionals and parents facing this clinical situation, sometimes complicated by legal constraints.

Magnetic resonance imaging evaluation of foetal intracranial haemorrhage and the correlation with ultrasound findings and postnatal outcomes

OBJECTIVES

The aim of the study was to compare the magnetic resonance imaging (MRI) findings of intracranial haemorrhage (ICH) in the middle- and late trimesters and to explore the relationship between the MRI features of foetal ICH and postnatal outcomes.

METHODS

This was a retrospective study which recruited foetal ICH diagnosed by MRI in one tertiary centre from 2015 to 2019. The prenatal and postnatal medical records were reviewed.

RESULTS

Of 39 ICH cases, 82.1% (32) had germinal matrix intraventricular haemorrhage (GM-IVH), and 18.9% (7) were diagnosed with non-GM-IVH. The cerebellum, corpus callosum and subdural space were affected in 5, 1 and 1 non-GM-IVH cases, respectively. MRI confirmed possible ICH on sonogram in 10 cases (35.7%) and the remaining 19 added ICH diagnoses that were not obtained on initial ultrasound imaging. Pregnancy outcome data were available in 82.1% of (32) cases, of which 21 were terminated pregnancies, 1 was foetal demise and 10 were delivered. One neonate died after birth and one infant suffered from hearing loss. The remaining eight patients had favourable outcome.

CONCLUSION

In our study, evaluation of the relationship between MRI findings and outcomes remains challenging, depending on the timing of examination and the hematoma itself. MRI was an adjunct to US in diagnosing ICH in utero which helps to assess postnatal development.

The added value of third trimester fetal brain MRI in cases of isolated ventriculomegaly

OBJECTIVES

To assess the added value of third trimester fetal brain MRI, performed in one tertiary referral center, in cases of isolated ventriculomegaly as established by a dedicated multiplanar neurosonography.

METHODS

Fetal brain MRI scans performed in a single tertiary center during a 3-year period were assessed for possible inclusion. Only cases diagnosed with ventriculomegaly without additional findings in a neurosonography preceding the MRI were included. Fetal MRI was performed at a median gestational of 32 weeks (IQR 31-34 weeks).

RESULTS

A total of 68 cases met the inclusion criteria. Of them, in four cases MRI identified additional findings including three cases of intraventricular hemorrhage and one case of cortical infarction. The overall rate of MRI-findings in the study population was (5.9%, 95% CI 2.3-14.2%). No additional findings were detected in cases of mild ventriculomegaly, 6.1% in moderate and 25% in severe ventriculomegaly. The combined rate of additional findings in mild to moderate ventriculomegaly was 3.3% (95%CI 0.9-11.4%).

CONCLUSIONS

MRI was able to detect additional findings in 5.9% of cases with seemingly isolated ventriculomegaly after a dedicated neurosonography. The severity of ventriculomegaly is associated with a higher chance of detecting abnormalities in fetal brain MRI.

Usefulness of prenatal magnetic resonance imaging in differential diagnosis of fetal congenital cystic adenomatoid malformation and bronchopulmonary sequestration

BACKGROUND

Congenital cystic adenomatoid malformation (CCAM) and bronchopulmonary sequestration (BPS) are the most common lung diseases in fetuses. There are differences in the prognosis and treatment of CCAM and BPS, and the clinical diagnosis and treatment plan is usually prepared prior to birth. Therefore, it is quite necessary to make a clear diagnosis before delivery. CCAM and BPS have similar imaging features, and the differentiation mainly relies on the difference in supply vessels. However, it is hard to distinguish them due to invisible supplying vessels on some images.

AIM

To explore the application value of magnetic resonance imaging (MRI) in the differential diagnosis of fetal CCAM and BPS.

METHODS

Data analysis for 32 fetuses with CCAM and 14 with BPS diagnosed by prenatal MRI at Huzhou Maternal and Child Health Care Hospital and Anhui Provincial Children’s Hospital from January 2017 to January 2020 was performed to observe the source blood vessels of lesions and their direction. Pathological confirmation was completed through CT examination and/or operations after birth.

RESULTS

After birth, 31 cases after birth were confirmed to be CCAM, and 15 were confirmed to be BPS. The CCAM group consisted of 21 macrocystic cases and 10 microcystic cases. In 18 cases, blood vessels were visible in lesions. Blood supply of the pulmonary artery could be traced in eight cases, and in 10 cases, only vessels running from the midline to the lateral down direction were observed. No lesions were found in four macrocystic cases and one microcystic case with CCAM through CT after birth; two were misdiagnosed by MRI, and three were misdiagnosed by prenatal ultrasonography. The BPS group consisted of 12 intralobar cases and three extralobar cases. Blood vessels were visible in lesions of nine cases, in four of which, the systemic circulation blood supply could be traced, and in five of which, only vessels running from the midline to the lateral up direction were observed. Three were misdiagnosed by MRI, and four were misdiagnosed by prenatal ultrasonography.

CONCLUSION

CCAM and BPS can be clearly diagnosed based on the origin of blood vessels, and correct diagnosis can be made according to the difference in the direction of the blood vessels, but it is hard distinguish microcystic CCAM and BPS without supplying vessels. In some CCAM cases, mainly the macrocystic ones, the lesions may disappear after birth.

Neurodevelopmental Outcomes following Prenatal Diagnosis of Isolated Corpus Callosum Agenesis: A Systematic Review

Abnormalities of corpus callosum are one of the most common brain anomalies. Fetuses with isolated corpus callosum agenesis (CCA) have a better prognosis than those with additional anomalies. However, unpredictable neurodevelopmental outcomes of truly isolated CCA make prenatal counseling a challenge. The aim of this review is to evaluate neurodevelopmental outcomes in children with prenatal diagnosis of isolated CCA. Controlled clinical trials published between May 23, 2009, and May 23, 2019, using the MeSH term "agenesis of corpus callosum" were reviewed. A total of 942 articles were identified, and 8 studies were included in the systematic review depending on the inclusion criteria. These studies included 217 fetuses with isolated CCA and no other anomalies at prenatal assessment. Neurodevelopmental outcome was reported to be normal in 83 children with a prenatal diagnosis of isolated CCA confirmed at birth within 128 completed assessments. About 45 children presented borderline, moderate, or severe neurodevelopmental outcome. In this review, neurodevelopment was favorable in two-thirds of the cases, but mild disabilities emerged in older children. Despite this, disabilities can occur later beyond school age and a low risk of severe cognitive impairment exists. Our study highlights the essential early diagnosis and proper supportive therapy.

Detecting Fetal Central Nervous System Anomalies Using Magnetic Resonance Imaging and Ultrasound

Background:

Most fetal abnormalities can be detected on ultrasound, the evaluation of fetal CNS abnormalities can be limited by various factors, including obesity, polyhydramnios, multiple pregnancies, and increased cranial ossification during the third trimester.

Objective:

This study aimed to evaluate the ability to detect fetal central nervous system (CNS) anomalies using in utero magnetic resonance imaging (iuMRI) and ultrasound (US) techniques.

Methods:

This prospective study was approved by the institutional review board (Ref: 2968/QĐ-ĐHYHN dated 11 July 2019), and the requirement to obtain the informed consent of patients was waived. This study included 66 fetuses with diagnosed or suspected CNS abnormalities based on the results of a prenatal screening US performed at the antenatal diagnosis center of the Central Obstetrics and Gynecology Hospital. All pregnant women with a suspected diagnosis of abnormal fetal CNS on US underwent 1.5-Tesla iuMRI within 14 days of the US at Hanoi Medical University Hospital between June 2019 and June 2020. Cohen’s kappa coefficient (κ) was used to determine the agreement between US and iuMRI findings.

Results:

A total of 66 pregnant women were examined, including 66 fetuses, for which 79 abnormalities were detected by US and 98 abnormalities were detected by iuMRI. The average gestational age was 29 weeks and 6 days. The comparison of iuMRI and US findings revealed similar diagnoses for 71 abnormalities (67%) and different diagnoses for 35 abnormalities (33%). The level of agreement between US and iuMRI was almost perfect for ventriculomegaly and cystic lesions, with κ values 0.87 and 0.84, respectively. The level of agreement between US and iuMRI was the weakest for hemorrhage, with a κ value 0 (no agreement), and cortical abnormalities, with a κ value of 0.46 (weak agreement).

Conclusion:

The level of agreement between US and iuMRI diagnoses was almost perfect for the detection of ventriculomegaly and was weakest for the detection of hemorrhage and cortical abnormalities, which were abnormalities detected by iuMRI but not by ultrasound.

Magnetic resonance imaging of the fetal central nervous system: Timing and consistency between pre- and postnatal diagnoses

INTRODUCTION

It has been shown that a proper comparison of prenatal ultrasound and magnetic resonance imaging (MRI) is possible only in the case of a short interval between tests. However, it is worth noting that the reference test is a postnatal examination. The aim of our study was to evaluate the effect of time between prenatal MRI (pMRI) and postnatal examinations on the consistency of diagnoses.

MATERIAL AND METHODS

The prospective observational study was carried out between 2014 and 2017 at the Department of Obstetrics and Perinatology of Krakow University Hospital. In total, 60 patients with fetuses suspected of central nervous system (CNS) defects were included in the study group. PMRI examinations were conducted in the third trimester of pregnancy.

RESULTS

The median gestational age of pMRI was 35 weeks and median of the time interval between carrying out pre- and postnatal test was 34.5 days. In the group of nonconcordant diagnoses, the interval was longer. The analysis did not show a statistically significant relationship between consistency of diagnoses and timing of pMRI. The median time of pregnancy at which pMRI was performed was similar in both groups. A prolongation of the interval between examinations reduced the probability of consistency of diagnoses.

CONCLUSIONS

The number of inaccurate results increased with the prolongation of the interval between pre- and postnatal tests.

KEY MESSAGE

Prolongation of the interval between pre- and postnatal increases number of inaccurate results.

Real-Life Diagnostic Accuracy of MRI in Prenatal Diagnosis

There is some controversy about the value of fetal MRI in prenatal diagnosis, and most of the studies examine its accuracy in central nervous system (CNS) pathology. The objective of this retrospective study was to assess the diagnostic accuracy and usefulness of fetal MRI in the prenatal diagnosis of central nervous system (CNS) pathology and non-CNS pathology. Patients referred to the Radiology Department between 2007 and 2018 for a fetal MRI after detection of an anomaly in the fetal ultrasound, a high-risk pregnancy, or an inconclusive fetal ultrasound (n = 623) were included in the study. Postnatal diagnosis was used to assess the diagnostic accuracy of MRI. Fetal MRI was considered to provide additional information over fetal ultrasound when findings of the fetal MRI were not detected in the fetal ultrasound or when established a pathological condition that was not detected in the fetal ultrasound. Fetal MRI provided useful information for the perinatal management and prognosis over fetal ultrasound when findings of the fetal MRI changed the postnatal prognosis, leaded to the decision to legally terminate the pregnancy, changed prenatal or postnatal follow-up, or helped in the planning of prenatal or postnatal treatment. Fetal MRI offered an accurate diagnosis in 97% of cases (compared to 90.4% of fetal ultrasound; p < 0.001). Concordance between fetal ultrasound and fetal MRI was 92.1%. Fetal MRI provided additional information over fetal ultrasound in 23.1% of cases. In 11.6% of cases, the information was useful for the perinatal management and prognosis. In 45 cases (7.2%), fetal MRI was the only accurate diagnosis. In conclusion, fetal MRI has a superior diagnostic accuracy, especially in CNS pathology, and provides additional useful information in CNS, thoracic, and abdominal pathology.

Prenatal diagnosis of central nervous system abnormalities: Neurosonography versus fetal magnetic resonance imaging

OBJECTIVE

To share our experience in diagnosis of congenital central nervous system (CNS) abnormalities by fetal magnetic resonance imaging (MRI).

STUDY DESIGN

This study consisted of 110 pregnancies. Neurosonography (NS) findings were compared with MRI results. Anomalies were categorized into 10 groups: 1) Corpus callosum (CC) and cavum septum pellucidum (CSP) anomalies, 2) Neural tube defects (NTD), 3) Posterior fossa anomalies (PFA), 4) Primary ventriculomegaly (PVM), 5) Microcephaly, 6) Macrocephaly, 7) Periventricular leukomalacia (PVL), 8) Craniosynostosis, 9) Intracranial hemorrhage (ICH) and 10) Lumbosacral teratoma. Demographic features, clinical characteristics and perinatal outcomes of the study subjects were evaluated.

RESULTS

Gestational weeks for NS and for MRI were 25.5 and 26.5 weeks, respectively. Fourteen (12.7%) pregnancies were terminated. PVM (n = 36, 32.7%), CC and CSP anomalies (n = 29, 26.3%), PFA (n = 11, 10%) and NTD (n = 11, 10%) were the most common fetal MRI indications. There were no statistically significant differences between the accuracy of fetal NS and fetal MRI for CC and CSP anomalies, NTDs, PFA and PVM (p = 0.09, 0.43, 0.45 and 0.23, respectively). However, fetal MRI was more accurate for the detection of normal anatomic findings in cases with suspected microcephaly, macrocephaly and craniosynostosis in NS when pooled together (p = 0.007). Furthermore, MRI also seemed to be advantageous in CC & CSP anomalies though it was not validated by statistical measures. No statistically significant difference was found for diagnostic performance of NS and MRI according to gestational week (p = 0.27).

CONCLUSION

Fetal MRI in addition to NS may improve diagnostic accuracy in pregnancies with congenital CNS abnormalities.

The Value of Imagistics in Early Diagnosis of Tuberous Sclerosis

Tuberous sclerosis complex is a multisystemic genetic disorder with high phenotypical variability. Its progress frequently brings along autism (61%), epilepsy, intellectual disability (45%), and neurocognitive impairment (Gipson and Johnston, 2017). We are considering the case of an infant suspected with tuberous sclerosis complex by imagistic investigation in the prenatal period. The pre- and postnatal ultrasound, fetal MRI, ophthalmoscopy, and dermatological and neurological examinations were used for diagnosis and follow-up. The seven major and minor criteria were regarded as sufficient for accurate diagnosis.

Significance of isolated borderline ventriculomegaly

PURPOSE

Foetal ventriculomegaly (VM) is one of the most commonly diagnosed brain abnormalities. The aims of this study were to assess cases with isolated VM, describe the prenatal course and assess short- and long-term follow-up at the age of 2 years.

METHODS

We performed a retrospective analysis from our prenatal data base and included all children that were prenatally diagnosed with VM in our unit between 2008 and 2013 (n = 250). Prenatal management, postnatal outcome and neurologic development at the age of 2 years were evaluated.

RESULTS

A total of 106 children were born at our institution and were diagnosed prenatally with isolated borderline VM. A total of 1.9% (n = 2/106) was transferred to the neonatal unit. A total of 0.9% (n = 1/106) showed abnormal findings in postnatal brain ultrasound. A total of 1.9% (n = 2/106) showed mild neurologic abnormalities after birth, but none had to be seen by a neuropediatrician. At the follow-up at 2 years, 2.5% (n = 1/40) had an insertion of a shunt.

CONCLUSION

Based on our analysis, the majority of isolated borderline VM do not show short- or long-term neurological abnormalities. However, all cases of VM should be referred to a detailed prenatal ultrasound exam by a specialist.

Is fetal magnetic resonance imaging indicated in patients with isolated ventriculomegaly?

OBJECTIVE

Ventriculomegaly is one of the most common anomalies encountered at obstetric ultrasound and it necessitates follow up. Fetal magnetic resonance imaging (MRI) can be used to confirm the ultrasound diagnose or to detect additional anomalies. Aim of this study is to assess follow up and management of fetal ventriculomegaly shown by ultrasound, and to evaluate additional diagnostic contribution of MRI.

STUDY DESIGN

This study was conducted retrospectively including 89 patients who had fetal MRI subsequent to ultrasound diagnose of ventriculomegaly in between 2011-2017. Medical records of patients were investigated and accompanying anomalies, congenital infection, chromosomal examination, degree and progression of ventriculomegaly, neonatal imaging and diagnose, and neurodevelopmental findings on follow up were evaluated. Patients were classified in two groups as isolated and nonisolated ventriculomegaly, and subgroups mild, moderate, severe were formed according to their findings. SPSS 23.0 programme was used for statistical analysis.

RESULTS

Ultrasound and following MRI was performed in a range of 18-35^th gestational weeks, diagnoses were isolated ventriculomegaly for 56 patients and nonisolated ventriculomegaly for 33 patients. Progression and neurodevelopmental delay was higher in severe nonisolated ventriculomegaly group. There was not significant contribution of MRI in the follow up of isolated ventriculomegaly (p < 0.001), and diagnostic imaging findings declined in neonatal period with proceeding normal neurodevelopment in 92.7% of patients followed with diagnosis of isolated ventriculomegaly.

CONCLUSION

When isolated ventriculomegaly is detected, ultrasound performed by an experienced team is mostly sufficient. MRI can be used in suspicious cases or when ventriculomegaly progresses.

MRI and US in the evaluation of fetal anomalies: The need to work together

PURPOSE

Real-time virtual sonography (RVS) is a new technique that synchronizes real-time ultrasonography (US) and multiplanar reconstructed magnetic resonance imaging (MRI). The purpose of this study was to evaluate the feasibility and ability of RVS to assess the main pathologies in fetuses with suspected US anomalies.

METHOD AND MATERIALS

Real-time virtual sonography (Hitachi, HI VISION Ascendus) was offered to 30 patients who had undergone fetal MRI. The acquired MRI image dataset was loaded into the fusion system and displayed together with the real-time US image. The ability of RVS to assess the main anatomical sites and fetal anomalies was evaluated.

RESULTS

Real-time virtual sonography was technically possible in all cases. From a total of 30 patients, RVS helped the diagnosis in 10 cases. In 15 cases of encephalic pathology, fusion imaging improved the accuracy of the diagnosis; in the other 5 cases, MRI was superior to US even when using the RVS.

CONCLUSION

This is a study on the feasibility and practical use of RVS. Thanks to information from both US and MRI, RVS allowed better identification of the fetal pathologies and improved the performance of the ultrasound examination. In our experience, it was really helpful in pathologies that would benefit from US follow-up.

A systematic review and meta-analysis to determine the contribution of mr imaging to the diagnosis of foetal brain abnormalities In Utero

Objectives

This systematic review was undertaken to define the diagnostic performance of in utero MR (iuMR) imaging when attempting to confirm, exclude or provide additional information compared with the information provided by prenatal ultrasound scans (USS) when there is a suspicion of foetal brain abnormality.

Methods

Electronic databases were searched as well as relevant journals and conference proceedings. Reference lists of applicable studies were also explored. Data extraction was conducted by two reviewers independently to identify relevant studies for inclusion in the review. Inclusion criteria were original research that reported the findings of prenatal USS and iuMR imaging and findings in terms of accuracy as judged by an outcome reference diagnosis for foetal brain abnormalities.

Results

34 studies met the inclusion criteria which allowed diagnostic accuracy to be calculated in 959 cases, all of which had an outcome reference diagnosis determined by postnatal imaging, surgery or autopsy. iuMR imaging gave the correct diagnosis in 91 % which was an increase of 16 % above that achieved by USS alone.

Conclusion

iuMR imaging makes a significant contribution to the diagnosis of foetal brain abnormalities, increasing the diagnostic accuracy achievable by USS alone.

Key points

• Ultrasound is the primary modality for monitoring foetal brain development during pregnancy

• iuMRI used together with ultrasound is more accurate for detecting foetal brain abnormalities

• iuMR imaging is most helpful for detecting midline brain abnormalities

• The moderate heterogeneity of reviewed studies may compromise findings

MRI of the Fetal Brain

The purpose of this article is to provide an overview of the possibilities for fetal magnetic resonance imaging (MRI) in the evaluation of the fetal brain. For brain pathologies, fetal MRI is usually performed when an abnormality is detected by previous prenatal ultrasound, and is, therefore, an important adjunct to ultrasound. The most commonly suspected brain pathologies referred to fetal MRI for further evaluation are ventriculomegaly, missing corpus callosum, and abnormalities of the posterior fossa. We will briefly discuss the most common indications for fetal brain MRI, as well as recent advances.

Quantitative magnetic resonance imaging of the fetal brain in utero: Methods and applications

Application of modern magnetic resonance imaging (MRI) techniques to the live fetus in utero is a relatively recent endeavor. The relative advantages and disadvantages of clinical MRI relative to the widely used and accepted ultrasonographic approach are the subject of a continuing debate; however the focus of this review is on the even younger field of quantitative MRI as applied to non-invasive studies of fetal brain development. The techniques covered under this header include structural MRI when followed by quantitative (e.g., volumetric) analysis, as well as quantitative analyses of diffusion weighted imaging, diffusion tensor imaging, magnetic resonance spectroscopy and functional MRI. The majority of the published work reviewed here reflects information gathered from normal fetuses scanned during the 3^rd trimester, with relatively smaller number of studies of pathological samples including common congenital pathologies such as ventriculomegaly and viral infection.

Exome sequencing for gene discovery in lethal fetal disorders--harnessing the value of extreme phenotypes

Massively parallel sequencing has revolutionized our understanding of Mendelian disorders, and many novel genes have been discovered to cause disease phenotypes when mutant. At the same time, next-generation sequencing approaches have enabled non-invasive prenatal testing of free fetal DNA in maternal blood. However, little attention has been paid to using whole exome and genome sequencing strategies for gene identification in fetal disorders that are lethal in utero, because they can appear to be sporadic and Mendelian inheritance may be missed. We present challenges and advantages of applying next-generation sequencing approaches to gene discovery in fetal malformation phenotypes and review recent successful discovery approaches. We discuss the implication and significance of recessive inheritance and cross-species phenotyping in fetal lethal conditions. Whole exome sequencing can be used in individual families with undiagnosed lethal congenital anomaly syndromes to discover causal mutations, provided that prior to data analysis, the fetal phenotype can be correlated to a particular developmental pathway in embryogenesis. Cross-species phenotyping allows providing further evidence for causality of discovered variants in genes involved in those extremely rare phenotypes and will increase our knowledge about normal and abnormal human developmental processes. Ultimately, families will benefit from the option of early prenatal diagnosis.