Prenatal neurologic anomalies: sonographic diagnosis and treatment

Anomalies of the Corpus Callosum in Prenatal Ultrasound: A Narrative Review for Diagnosis and Further Counseling

The corpus callosum is the major interhemispheric tract that plays an important role in neurological function. Understanding the etiology and embryology development helps the ultrasound diagnosis for disorders of the corpus callosum and further counseling. The nonvisualization of cavum septum pellucidum or dysmorphic cavum septum pellucidum in axial view are indirect signs for beginners to diagnose complete agenesis of corpus callosum (cACC) and partial agenesis of the corpus callosum (pACC). Further coronal view, sagittal view, and fetal magnetic resonance imaging are also important for evaluation. Genetic testing plays an essential tool in anomalies of corpus callosum by revealing the underlying genetic pathophysiology, such as chromosomal anomalies and numerous monogenetic disorders in 30%-45% of ACC. Diagnosis and prediction of prognosis for hypoplasia or hyperplasia of the corpus callosum are more difficult compared to cACC and pACC because of the limited reports in the literature. However, the complex types often had poorer prognostic outcomes compared to the isolated types. Hence, it is important to evaluate and follow fetal conditions thoroughly to rule out intracranial or extracranial anomalies in other systems.

Ultrasonographic Signs of Cytomegalovirus Infection in the Fetus-A Systematic Review of the Literature

BACKGROUND

congenital cytomegalovirus (cCMV) infection during pregnancy is a significant risk factor for fetal and neonatal morbidity and mortality. CMV detection is based on the traditional ultrasound (US) and MRI (magnetic resonance) approach.

METHODS

the present review used the PRISMA protocol for identification of studies associated with CMV infection and sonographic analysis. Various search terms were created using keywords which were used to identify references from Medline, Pubmed, PsycInfo, Scopus and Web of Science.

RESULTS

sonographic analysis of the cCMV infection identified several of the key features associated with fetuses. The presence of abnormal patterns of periventricular echogenicity, ventriculomegaly and intraparenchymal calcifications is indicative of CMV infection in the fetus. Hyperechogenic bowels were seen frequently. These results correlate well with MRI data, especially when targeted transvaginal fetal neurosonography was carried out.

CONCLUSIONS

ultrasonography is a reliable indicator of fetal anomalies, due to cCMV. Fetal brain and organ changes are conclusive indications of infection, but many of the ultrasonographic signs of fetal abnormality could be due to any viral infections; thus, further research is needed to demarcate CMV infection from others, based on the ultrasonographic approach. CMV infection should always be an indication for targeted fetal neurosonography, optimally by the transvaginal approach.

Evaluation of prenatal central nervous system anomalies: obstetric management, fetal outcomes and chromosome abnormalities

Objective

To study the outcomes of fetuses who were diagnosed with central nervous system (CNS) anomalies during prenatal period and to describe the obstetric management of those pregnancies.

Methods

In this retrospective study, fetuses who were detected to have central nervous system anomalies by prenatal ultrasound from January 2010 to December 2019 were recruited. Data regarding prenatal diagnosis and obstetric outcomes were retrieved from maternal and paediatric records. The prognosis of fetuses who were born alive was classified based on their neurodevelopmental outcome within two years of life.

Results

There were a total of 365 fetuses with CNS anomalies within the 10-year study period, with a mean gestational age of 24.65±7.37 weeks at diagnosis. Ventriculomegaly (23.36%) was the commonest CNS anomalies seen. 198 (54.20%) of these fetuses had associated extra-CNS anomalies, with cardiovascular being the most common system involved. Fetal karyotyping was performed in 111 pregnancies, with chromosomal aberrations detected in 53 (49.07%) cases and culture failure in 3 cases. Majority of the chromosomal abnormalities were Edward syndrome (trisomy 18) and Patau syndrome (trisomy 13). Fetuses with congenital CNS anomalies and abnormal chromosomal karyotyping were more likely to be diagnosed earlier by prenatal ultrasound and tend to have poorer obstetric and neurocognitive prognosis. Prenatally, 86 (23.56%) of the cases were lost to follow up and likely to deliver elsewhere. Among the 279 cases whom their pregnancy outcomes were available, 139 (49.82%) pregnancies resulted in live births, 105 (37.63%) pregnancies were electively terminated, while the remaining 35 (12.54%) pregnancies ended in spontaneous loss. The decision of termination of pregnancy largely depends on mean diagnostic gestational age, presence of chromosomal aberrations and abnormal amniotic fluid volume in those fetuses. Two years after delivery, only 75 (53.96%) children out of 139 live births were still alive, 43 (30.93%) died and 21 (15.11%) cases were lost to follow-up. 32 (23.02%) children with prenatally diagnosed CNS anomalies had normal neurodevelopmental outcome. The presence of multiple CNS anomalies and involvement of extra-CNS anomalies indicated a poorer neurodevelopmental prognosis.

Conclusion

Less than 50% of fetuses with prenatally diagnosed CNS anomalies resulted in live births. Even if they survive till delivery, 36.45% of them passed away within 2 years and 62.79% of children who survived till 2 years old had neurodevelopmental disability.

Dandy-Walker malformation in methylmalonic acidemia: a rare case report

Background

Methylmalonic acidemia is an organic acid metabolism disorder that usually has nonspecific clinical manifestations.

Case presentation

A 3-month-old female infant was admitted to the hospital for developmental retardation. Her prenatal and birth history was unremarkable. After admission, she developed dyspnea and severe anemia and was subsequently transferred to the intensive care unit. Magnetic resonance imaging of her brain showed a Dandy-Walker malformation, and metabolic screening indicated methylmalonic acidemia. Thus, she was diagnosed with methylmalonic acidemia and Dandy-Walker malformation. The patient underwent treatment including acidosis correction, blood transfusion, antibiotics, mechanical ventilation and heat preservation. Unfortunately, her condition progressively worsened and she died of metabolic crisis.

Conclusions

Dandy-Walker malformation may be a clinical manifestation of methylmalonic acidemia. Additionally, the co-existence of methylmalonic acidemia and Dandy-Walker malformation may be an uncharacterized syndrome which needs to be studied further.

Massive posterior cranial vault erosion and its reconstruction: A peculiar presentation of "mega cisterna magna"

Dandy-Walker (DW) complex is a rare central nervous system malformation, commonly associated with complex non-neurological conditions, defined by four variants with characteristic anatomic features, still inadequately known for its etiological aspects. "Mega Cisterna Magna" (MCM) is a type of DW complex which is represented by an enlarged posterior cranial fossa. Though reduction cranioplasty has been reported in enlarged posterior cranial fossa malformations, however we report a peculiar case of MCM with massive posterior cranial bone erosion, presenting completely asymptomatic at an age of 8 years, without any associated co-morbidities till date, nor with any evident occipital mass at birth. Survival of the child till this age is an exception in itself, but this can probably be explained by the presence of the giant defect of the posterior cranial bone, which must have acted like a vent and prevented the elevation of the ICP. Hence no symptoms were observed till date. Ventriculo-peritoneal (VP) shunting was done to drain the accumulated fluid, followed by massive cranioplasty, which was challenging and was performed with autologous cranial and fibular bone grafts, along with alloplastic titanium mesh, and thus achieving marked aesthetic improvement with satisfactory bone healing at a 3-year follow-up.

Prenatal detection of congenital anomalies and related factors in Argentina

Congenital anomalies (CAs) are a leading cause of neonatal death. Many CAs can be diagnosed prenatally. To estimate the prenatal detection rate (PDR) of CA in hospitals participating in the RENAC (National Network of Congenital Anomalies of Argentina) and to analyze the PDR according to different factors. Sources were reports of RENAC from the 2013-2016 period. Congenital anomalies included were those detectable by ultrasound or by a prenatal karyotype. PDR was calculated by region, health subsector, clinical presentation, maternal age, sex, and twining. Using multiple logistic regression analysis, we evaluated predictors of prenatal detection. In total, 9976 cases were defined as prenatal detectable; 5021 were detected (PDR = 50.3%). Multiple presentation increased the chances of prenatal detection (Adj. OR = 1.6; 95%CI 1.4-1.9). Prenatal detection was lower in the public subsector (Adj. OR = 0.8; 95%CI 0.7-0.9) and in the northern regions of the country. PDR was higher than 75% in isolated cases of urinary malformation, anencephaly, and gastroschisis. Prenatal detection increased the chance of birth in higher complexity-level hospitals (Adj. OR = 2.5; 95%CI 2.3-2.8). PDR was within the range previously reported. Heterogeneity between regions and health subsector suggests the need for training to achieve equity in detection.

Factors associated with the timing of the first prenatal ultrasound in Canada

Background

The aim of this study was to investigate the factors associated with the timing of the first prenatal ultrasound in Canada.

Methods

This was a secondary data analysis of the Maternity Experiences Survey, a cross-sectional survey covering different aspects of pregnancy, labour, birth and the post-partum period. Bivariate and multivariate multinomial logistic regressions were performed to assess the relationship between timing of first prenatal ultrasound and different independent variables.

Results

68.4% of Canadian women received an optimally timed first prenatal ultrasound, 27.4% received early ultrasounds and 4.3% received late ultrasound. The highest prevalence of early ultrasound was in Ontario (33.3%) and the lowest was in Manitoba (13.3%). The highest prevalence of late ultrasound was found in Manitoba (12.1%) and the lowest was in British Columbia and Ontario (3.5% each). The highest prevalence of optimal timing of first prenatal ultrasound was in Quebec (77%) and the lowest was in Ontario (63.2%). Factors influencing the timing of ultrasound included: Early – maternal age < 20 (adjusted OR = 0.54, 95%CI:0.34–0.84), alcohol use during pregnancy (adjusted OR = 0.69, 95%CI:0.53–0.90), history of premature birth (adjusted OR = 1.41, 95%CI:1.06–1.89), multiparity (adjusted OR = 0.67, 95%CI:0.57–0.78), born outside of Canada (adjusted OR = 0.82, 95%CI:0.67–0.99), prenatal care in Newfoundland and Labrador (adjusted OR = 1.66, 95%CI:1.20–1.30), Nova Scotia (adjusted OR = 1.68, 95%CI:1.25–2.28), Ontario (adjusted OR = 2.16, 95%CI:1.76–2.65), Saskatchewan (adjusted OR = 1.50, 95%CI:1.05–2.14), Alberta (adjusted OR = 1.37, 95%CI:1.05–1.77) British Columbia (adjusted OR = 1.90, 95%CI:1.45–2.50) and Manitoba (adjusted OR = 0.66, 95%CI:0.45–0.98) Late – unintended pregnancy (adjusted OR = 1.89, 95%CI:1.38–2.59), born outside of Canada (adjusted OR = 1.75, 95%CI:1.14–2.68), prenatal care in Manitoba (adjusted OR = 2.88, 95%CI:1.64–5.05) and the Territories (adjusted OR = 4.50, 95%CI:2.27–8.93). An interaction between history of miscarriage and having ‘other’ prenatal care provider significantly affected timing of ultrasound (adjusted OR = 0.31, 95%CI:0.14–0.66).

Conclusion

Only 68% of Canadian women received an optimally timed prenatal ultrasound which was influenced by several factors including province of prenatal care, maternal age and country of birth, and an interaction effect between prenatal care provider and history of miscarriage. These findings establish a baseline of factors influencing the timing of prenatal ultrasound in Canada, which can be built upon by future studies.

Differential Diagnoses and Their Implications of Dandy-Walker Malformation or Isolated Cisterna Magna, a Case Study: Baby V

We explore the outcome of a fetus with a posterior fossa abnormality thought to be a Dandy-Walker malformation based on prenatal ultrasound imaging. The infant was later diagnosed by magnetic resonance imaging (MRI) as having an isolated cisterna magna. When assessing brain abnormalities, there is increased accuracy of prenatal MRI versus prenatal ultrasound. Accurate diagnosis of an infant is paramount so that an inheritance pattern, risk of recurrence, involvement of other systems, and a prognosis can be determined. Communicating with the family and supporting them with the correct information is then enhanced. It should be standard protocol to obtain a fetal MRI if an abnormal prenatal ultrasound of the brain is detected. Further research is needed to assess the accuracy of using MRI versus ultrasonography prenatally to diagnose posterior brain abnormalities.

Virtual reality objects improve learning efficiency and retention of diagnostic ability in fetal ultrasound

OBJECTIVE

Virtual reality (VR) objects of fetal ultrasound volumes have been proposed for teaching and learning diagnostic ultrasound. The aim of this study was to determine if VR objects improve learning efficiency and retention of diagnostic ability in fetal ultrasound.

METHODS

Medical students and junior doctors were taught normal and abnormal sonographic fetal brain anatomy using conventional means (video lectures and review articles; control group) or additionally with selected VR objects from a novel fetal brain atlas (Pocket Brain, http://pb.fetal.ch; study group). Knowledge, speed of recognition and retention of diagnostic ability were tested in multiple-choice questionnaires 1 and 4 months after teaching, and the results were compared between those taught using conventional means only and those taught using VR objects.

RESULTS

Participants taught using VR objects answered significantly more questions correctly and solved the tests quicker than those taught using conventional methods only, both 1 and 4 months after teaching.

CONCLUSION

The use of VR objects in teaching fetal ultrasound significantly improves learning efficiency and knowledge retention. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Quantitative analysis of normal fetal medulla oblongata volume and flow by three-dimensional power Doppler ultrasound

OBJECTIVE

Assessment of the fetal medulla oblongata volume (MOV) and blood flow might be important in the evaluation of fetal brain growth. We used three-dimensional power Doppler ultrasound (3DPDUS) to assess the fetal MOV and blood flow index in normal gestation. The relationships between these parameters were further analyzed.

METHODS

We assessed the total volume and blood flow index of the fetal MO in normal pregnancies using a 3DPDUS (Voluson 730 Expert). The true sagittal plane over the fetal occipital area was measured by a 3D transabdominal probe to scan the fetal MO under the power Doppler mode. Then, we quantitatively assessed the total volume of the fetal MOV, mean gray area (MG), vascularization index (VI), and flow index (FI).

RESULTS

A total of 106 fetuses, ranging from 19 weeks to 39 weeks of gestation, were involved in our study. The volume of the fetal MO was highly positively correlated with gestational age [correlation coefficient (r) = 0.686, p < 0.0001]. The MG was negatively correlated with gestational age [r = -0.544, p < 0.0001). VI and FI showed no significant correlation with gestational age (p = 0.123 and p = 0.219, respectively).

CONCLUSION

3DPDUS can be used to assess the fetal MOV and blood flow development quantitatively. Our study indicated that fetal MOV and blood flow correlated significantly with the advancement of gestational age. This information may serve as reference data for further studies of the fetal brain and blood flow under abnormal conditions.

Trans-Pacific tele-ultrasound image transmission of fetal central nervous system structures

OBJECTIVE

To assess the quality of images and video clips of fetal central nervous (CNS) structures obtained by ultrasound and transmitted via tele-ultrasound from Brazil to Australia.

METHODS

In this cross-sectional study, 15 normal singleton pregnant women between 20 and 26 weeks were selected. Fetal CNS structures were obtained by images and video clips. The exams were transmitted in real-time using a broadband internet and an inexpensive video streaming device. Four blinded examiners evaluated the quality of the exams using the Likert scale. We calculated the mean, standard deviation, mean difference, and p values were obtained from paired t tests.

RESULTS

The quality of the original video clips was slightly better than that observed by the transmitted video clips; mean difference considering all observers = 0.23 points. In 47/60 comparisons (78.3%; 95% CI = 66.4-86.9%) the quality of the video clips were judged to be the same. In 182/240 still images (75.8%; 95% CI = 70.0-80.8%) the scores of transmitted image were considered the same as the original.

CONCLUSION

We demonstrated that long distance tele-ultrasound transmission of fetal CNS structures using an inexpensive video streaming device provided images of subjective good quality.

Fetal MRI: the sonographer's view

Fetal magnetic resonance imaging (MRI) is used with increasing frequency as a complementary imaging modality to ultrasound (US) in prenatal diagnosis. Fetal MRI displays the fetal, uterine, and extrauterine anatomy in ways that allow confirmation of normal anatomy and the diagnosis of pathological entities that were formerly very difficult to detect prenatally. Comparison of US views with standard orthogonal plane MR images reinforces the understanding of fetal anatomy as visualized with US. Technological advances in US equipment have allowed the recent description of subtle fetal anatomical structures. Similarly, knowledge of the MRI appearances of pathological conditions has opened opportunities for the sonographic diagnosis of entities such as brainstem malformations and alterations in the normal transient laminar pattern that occur during development of the fetal cerebrum. Fetal MRI can confirm suspicious US findings and thus add confidence in a particular prenatal diagnosis before performing invasive and interventional procedures. Specific MRI sequences can be used to add information about the chemical composition of fetal structures, such as fat, blood, and meconium. Dynamic MRI sequences have increased understanding of gestational age-dependent behavior, and assist the sonographer in assessment of fetal structural anomalies that cause abnormal movement and behavior. The technological ability of US to demonstrate very small structures complements the lower resolution of fetal MR images, whereas the ability of MR to visualize the whole fetus improves the limited views necessitated by US. Therefore, both US and fetal MRI have complementary strengths and weaknesses that can be used to full advantage in prenatal diagnosis.