Frequency and cause of disagreements in diagnoses for fetuses referred for ventriculomegaly

Imaging of fetal ventriculomegaly

Fetal ventriculomegaly is the most common central nervous system abnormality detected by prenatal imaging. It has a high association with other anomalies. Etiologies and prognoses for fetal ventriculomegaly range from normal outcomes to significant neurodevelopmental sequelae. In this paper, we review the development, terminology, pathogenesis, imaging and prognosis of fetal ventriculomegaly.

Analysis of errors made on in utero MR studies of the foetal brain in the MERIDIAN study

Objectives

In utero magnetic resonance (iuMR) imaging to diagnose foetal brain abnormalities has been established and is supported by meta-analyses of retrospective and prospective studies. In this paper we describe and classify the iuMR errors made in the largest diagnostic accuracy study to date (MERIDIAN). We also correlate the error rates and types with the prior experience of the reporting radiologists in order to inform how to provide a national programme with the best diagnostic accuracy achievable.

Methods

The MERIDIAN cohort of 570 foetus formed the basis of this study and included 40 cases with a confirmed diagnostic error, compared with the Outcome Reference Diagnosis. Analysis included the potential clinical effect of the error and classification of error type through an Expert Neuroradiological Panel re-reporting the study. Assessments were made regarding radiologists experience prior to MERIDIAN.

Results

The overall confirmed error rate for iuMR was 7·0% and it was considered that there would have been an adverse effect on prognostic information in 22/40 cases if the iuMR had informed counselling. The experienced central reporter made statistically significant fewer errors than the less experienced non-central reporters (3·8% v 11·0%) and the central reporter made fewer clinically significant errors. Furthermore, the type of cognitive errors differed between central and non-central reporters.

Conclusions

Although iuMR imaging improves the diagnostic accuracy of detecting foetal brain abnormalities there remains a substantial error rate, which can have major clinical significance. We have shown that error rates are lower for more experienced reporting radiologists with fewer potential deleterious clinical implications. We discuss the implications of these findings in terms of providing a uniform national service.

Key Points

• Overall confirmed error rate for iuMR diagnosing foetal brain abnormalities was 7·0%.

• IuMR reports had an adverse effect on counselling in 55% of error cases.

• Error rates are consistently lower for more experienced radiologists.

• Collaboration between radiologists, dual reporting, overseeing scan and formal training can reduce errors.

Electronic supplementary material

The online version of this article (10.1007/s00330-018-5508-x) contains supplementary material, which is available to authorized users.

Prevalence of defined ultrasound findings of unknown significance at the second trimester fetal anomaly scan and their association with adverse pregnancy outcomes: the Welsh study of mothers and babies population-based cohort

OBJECTIVE

The aim of this article was to estimate the population prevalence of seven defined ultrasound findings of uncertain significance ('markers') in the second trimester and the associated risk of adverse pregnancy outcomes.

METHOD

A prospective record-linked cohort study of 30 078 pregnant women who had second trimester anomaly scans between July 2008 and March 2011 in Wales was conducted.

RESULTS

The prevalence of markers ranged from 43.7 per 1000 singleton pregnancies for cardiac echogenic foci [95% confidence interval (CI): 38.8, 51.1] to 0.6 for mild-to-moderate ventriculomegaly (95% CI: 0.3, 1.0). Isolated echogenic bowel was associated with an increased risk of congenital anomalies [risk ratio (RR) 4.54, 95% CI: 2.12, 9.73] and preterm birth (RR 2.30, 95% CI: 1.08, 4.90). Isolated pelvicalyceal dilatation was associated with an increased risk of congenital anomalies (RR 3.82, 95% CI: 2.16, 6.77). Multiple markers were associated with an increased risk of congenital anomalies (RR 5.00, 95% CI: 1.35, 18.40) and preterm birth (RR 3.38, 95% CI 1.20, 9.53).

CONCLUSIONS

These data are useful for counselling families and developing clinical guidance and care pathways following the detection of markers in clinical practice, particularly the need for follow-up scans to monitor placental function and growth in pregnancies with isolated echogenic bowel, and further investigation for multiple markers. © 2015 The Authors. Prenatal Diagnosis published by John Wiley & Sons Ltd.

The history of imaging in obstetrics

During the past century, imaging of the pregnant patient has been performed with radiography, scintigraphy, computed tomography, magnetic resonance imaging, and ultrasonography (US). US imaging has emerged as the primary imaging modality, because it provides real-time images at relatively low cost without the use of ionizing radiation. This review begins with a discussion of the history and current status of imaging modalities other than US for the pregnant patient. The discussion then turns to an in-depth description of how US technology advanced to become such a valuable diagnostic tool in the obstetric patient. Finally, the broad range of diagnostic uses of US in these patients is presented, including its uses for distinguishing an intrauterine pregnancy from a failed or ectopic pregnancy in the first trimester; assigning gestational age and assessing fetal weight; evaluating the fetus for anomalies and aneuploidy; examining the uterus, cervix, placenta, and amniotic fluid; and guiding obstetric interventional procedures.

The Reliability of Fetal MRI in the Assessment of Brain Malformations

Objectives: To assess the inter- and intraobserver reliability of different fetal MRI measurements in cases of fetal brain malformations and to examine the concordance between ultrasonography (US) and MRI findings. Methods: Fetal brain MRIs and US findings of 56 pregnant women were retrieved from the institutional database. Standardized fetal brain MRI measurements were performed by 4 observers, and the inter- and intraobserver reliability was determined. Additionally, US and MRI findings were retrospectively compared. Results: The interobserver intraclass correlation coefficient (ICC) was above 0.9 for the cerebellum and posterior horn of the lateral ventricle. The measurements regarding the third ventricle (0.50), the fourth ventricle (0.58), and the corpus callosum (0.63) showed poor reliability. Overall, the intraobserver reliability was greater than the interobserver reliability. US and MRI findings were discordant in 29% of the cases with MRI rendering an extended diagnosis in 18%, a change of diagnosis in 3.6%, and excluding pathological findings suspected on US in 7.1%. Conclusions: Fetal MRI is a valuable complement to US in the investigation of fetal brain malformations. The reliability of most parameters was high, except for the measurements of the third and fourth ventricles and the corpus callosum.

False positive morphologic diagnoses at the anomaly scan: marginal or real problem, a population-based cohort study

BACKGROUND

Congenital malformations occur in 3-4% of live births. Their prenatal detection is performed by ultrasound screening. Any announcement about a suspected malformation is a source of stress for the parents, and misdiagnosis during ultrasound screening can lead to expensive and sometimes iatrogenic medical interventions. In this study, we aim to determine the false-positive rate, first overall and then by anatomical system, of ultrasound screening for congenital malformations in the second and third trimesters of pregnancy.

METHODS

Our sample includes all children born between 1 January, 2006, and 31 December, 2009, in the French region of Auvergne, whose mother had a prenatal ultrasound diagnosis of a congenital malformation during the second or third trimester of pregnancy confirmed by a follow-up ultrasound examination by an expert consultant ultrasonographer. The study included 526 fetuses, divided in 3 groups: false positives, diagnostic misclassifications, and true positives. The rates of false positives and diagnostic misclassifications were calculated for the sample as a whole and then by anatomical system.

RESULTS

Overall, the false-positive rate was 8.8% and the rate of diagnostic misclassification 9.2%. The highest false-positive rates were found for renal and gastrointestinal tract malformations, and the highest diagnostic misclassification rates for cerebral and cardiac malformations. The diagnostic misclassification rate was significantly higher than the false-positive rate for cardiac malformations.

CONCLUSION

The false-positive rate during prenatal ultrasound is not insignificant; these misdiagnoses cause psychological stress for the parents and overmedicalisation of the pregnancy and the child.

Ethics of prenatal ultrasound

Prenatal ultrasound has opened new opportunities to examine, diagnose and treat the fetus, but these advances bring with them ethical dilemmas. In this chapter, I address the ethical principles that need to be considered when treating both mother and fetus as patients, and how these can be applied in practice. In particular, ultrasound practitioners have an ethical duty to maintain their theoretical knowledge and practical skills to ensure they advise parents correctly. I also discuss the ethical issues in carrying out intrauterine therapy, ultrasound-related research, and termination of pregnancy for fetal abnormality.

Fetal cerebral imaging - ultrasound vs. MRI: an update

The purpose of this article is to analyze the advantages and limitations of prenatal ultrasonography (US) and magnetic resonance imaging (MRI) in the evaluation of the fetal brain. These imaging modalities should not be seen as competitive but rather as complementary. There are wide variations in the world regarding screening policies, technology, skills, and legislation about termination of pregnancy, and these variations markedly impact on the way of using prenatal imaging. According to the contribution expected from each technique and to local working conditions, one should choose the most appropriate imaging modality on a case-by-case basis. The advantages and limitations of US and MRI in the setting of fetal brain imaging are displayed. Different anatomical regions (midline, ventricles, subependymal area, cerebral parenchyma, pericerebral space, posterior fossa) and pathological conditions are analyzed and illustrated in order to compare the respective contribution of each technique. An accurate prenatal diagnosis of cerebral abnormalities is of utmost importance for prenatal counseling.

Callosal dysgenesis in fetuses with ventriculomegaly: levels of agreement between imaging modalities and postnatal outcome

OBJECTIVE

To assess neurodevelopmental outcome of fetuses diagnosed with callosal abnormalities after referral for ventriculomegaly.

METHODS

This sub-analysis of a prospective study of 430 fetuses, which were referred for ventriculomegaly and underwent sonography and magnetic resonance imaging (MRI), included those fetuses with a diagnosis of corpus callosal abnormalities after recruitment into the main study. Between three and six radiologists independently reviewed ultrasound and MR images and recorded central nervous system (CNS) abnormalities, with final diagnoses being decided by consensus. Postnatal outcomes of fetuses with callosal abnormalities were compared between those with and those without other abnormalities.

RESULTS

Callosal abnormalities were detected in 13% (58/430) of the fetuses referred with ventriculomegaly. Callosal dysgenesis was isolated in 24% (14/58) of these cases, with the remainder complicated by CNS, karyotypic or other major abnormalities. Five fetuses diagnosed prenatally as having isolated callosal abnormalities had additional CNS findings on postnatal assessment. Preconference kappa for callosal abnormalities was 0.76 for ultrasound and 0.78 for MRI, indicating that these investigations had a similar level of operator dependence. Neurodevelopmental outcome was normal or showed only mild delay that resolved in 67% (8/12) children with isolated callosal abnormalities compared to 7% (2/27) in those with non-isolated callosal abnormalities (P = 0.003).

CONCLUSION

Callosal abnormalities are present in a significant proportion of fetuses with a diagnosis of ventriculomegaly. Isolated callosal abnormalities are associated with normal neurodevelopmental outcome in approximately two-thirds of fetuses.

Prenatal-postnatal correlations of brain abnormalities: how lesions and diagnoses change over time

A combination of prenatal ultrasound and MRI can be used to detect and characterize many primary and secondary CNS abnormalities in the developing fetus. While this information is useful in prenatal patient counseling, it is important to understand the factors that can influence change in diagnosis and prognosis over time. The etiology of the abnormality, the conspicuity of associated findings, the change in appearance over time, and the opinion of subspecialty experts all can influence the diagnosis. Additionally, technical factors of imaging acquisition may allow the detection of an abnormality in the postnatal period and not prenatally. Having an understanding of the normal fetal central nervous system anatomy at varying gestational ages will aid in the imaging detection and interpretation of CNS pathology. Understanding how these appearances and diagnoses can change over time will aid in the discussion of prognosis with expectant parents, which is crucial in fetal CNS abnormalities.

Multi-atlas multi-shape segmentation of fetal brain MRI for volumetric and morphometric analysis of ventriculomegaly

The recent development of motion robust super-resolution fetal brain MRI holds out the potential for dramatic new advances in volumetric and morphometric analysis. Volumetric analysis based on volumetric and morphometric biomarkers of the developing fetal brain must include segmentation. Automatic segmentation of fetal brain MRI is challenging, however, due to the highly variable size and shape of the developing brain; possible structural abnormalities; and the relatively poor resolution of fetal MRI scans. To overcome these limitations, we present a novel, constrained, multi-atlas, multi-shape automatic segmentation method that specifically addresses the challenge of segmenting multiple structures with similar intensity values in subjects with strong anatomic variability. Accordingly, we have applied this method to shape segmentation of normal, dilated, or fused lateral ventricles for quantitative analysis of ventriculomegaly (VM), which is a pivotal finding in the earliest stages of fetal brain development, and warrants further investigation. Utilizing these innovative techniques, we introduce novel volumetric and morphometric biomarkers of VM comparing these values to those that are generated by standard methods of VM analysis, i.e., by measuring the ventricular atrial diameter (AD) on manually selected sections of 2D ultrasound or 2D MRI. To this end, we studied 25 normal and abnormal fetuses in the gestation age (GA) range of 19 to 39 weeks (mean=28.26, stdev=6.56). This heterogeneous dataset was essentially used to 1) validate our segmentation method for normal and abnormal ventricles; and 2) show that the proposed biomarkers may provide improved detection of VM as compared to the AD measurement.

Malformations of cortical development: diagnostic accuracy of fetal MR imaging

PURPOSE

To determine the diagnostic accuracy of fetal magnetic resonance (MR) imaging for malformations of cortical development by using postnatal MR imaging as reference standard.

MATERIALS AND METHODS

Eighty-one patients who had undergone fetal and postnatal MR imaging of the brain were identified in this institutional review board-approved, HIPAA-compliant study. Images were retrospectively reviewed in consensus by two pediatric neuroradiologists who were blinded to clinical information. Sensitivity and specificity were calculated according to retrospective review of the images and clinical reports for fetal MR images. The Fisher exact test was used to compare results for fetuses imaged before and after 24 gestational weeks and for image review versus clinical reports for fetal MR images.

RESULTS

Median gestational age at fetal MR imaging was 25.0 weeks (range, 19.71-38.14 weeks). Postnatal MR imaging depicted 13 cases of polymicrogyria, three cases of schizencephaly, and 15 cases of periventricular nodular heterotopia. Sensitivity and specificity of fetal MR imaging were 85% and 100%, respectively, for polymicrogyria; 100% each for schizencephaly; and 73% and 92%, respectively, for heterotopia. When heterotopia was seen in two planes, specificity was 100% and sensitivity was 67%. Sensitivity for heterotopia decreased to 44% for fetuses younger than 24 weeks. According to reports for fetal MR images, prospective sensitivity and specificity, respectively, were 85% and 99% for polymicrogyria, 100% and 99% for schizencephaly, and 40% and 91% for heterotopia.

CONCLUSION

Fetal MR imaging had the highest sensitivity for polymicrogyria and schizencephaly. Specificity was 100% for all cortical malformations when the abnormality was seen in two planes. Sensitivity for heterotopia was lower for fetuses younger than 24 weeks. Knowledge of the gestational age is important, especially for counseling patients about heterotopia.

Normative fetal brain growth by quantitative in vivo magnetic resonance imaging

OBJECTIVE

The objective of the study was to characterize total and regional volumetric brain growth in healthy fetuses during the second and third trimesters of pregnancy, using an automated method.

STUDY DESIGN

We developed and validated an automated method to quantify global and regional in vivo brain volumes using fetal magnetic resonance imaging. We then computed the percentage of growth for each brain structure in a cohort of 64 healthy fetuses (25.4-36.6 weeks' gestational age).

RESULTS

The cerebellum demonstrated the greatest maturation rate, with a 4-fold increase (384%) in volume between 25.4 and 36.6 weeks, and a relative growth rate of 12.87% per week. Both total brain and cerebral volumes increased by 230% and brain stem volume by 134% over the same gestational age period. Conversely, lateral ventricular volume decreased by 4.18% per week.

CONCLUSION

The availability and ongoing validation of normative fetal brain growth trajectories will provide important tools for early detection of impaired fetal brain growth upon which to manage high-risk pregnancies.

Ultrasound and MRI of fetuses with ventriculomegaly: can cortical development be used to predict postnatal outcome?

OBJECTIVE

The purpose of this study was to assess the conspicuity of brain cortical maturation with sonography and MRI of fetuses referred because of ventriculomegaly and to determine whether sulcal visualization can be used to predict postnatal outcome.

SUBJECTS AND METHODS

Women with 374 fetuses referred because of ventriculomegaly underwent sonography and MRI. Four to six radiologists rated visualization of 19 fissures or sulci. Majority opinion regarding sulcal visualization was compared among fetuses categorized by CNS abnormality: normal, isolated ventriculomegaly, and ventriculomegaly with additional CNS abnormalities. Live-born infants were categorized as having normal or abnormal development. Logistic regression analysis was used to correlate sulcal visualization and postnatal development. A subanalysis was performed with fetuses who had been classified prenatally as having a normal brain or isolated ventriculomegaly.

RESULTS

Cortical sulci were visualized more frequently and at an earlier gestational age with MRI than with ultrasound. In the entire cohort, the odds ratio of normal development ranged from 3.1 to 10.0 whenever the calcarine, parietooccipital, cingulate, superior temporal, precentral, or postcentral sulcus was seen on MR images. In fetuses categorized as having a normal brain or having isolated ventriculomegaly, the odds ratio of normal development ranged from 3.5 to 9.0 whenever the parietooccipital, cingulate, or superior temporal sulcus was seen.

CONCLUSION

Visualization of the sulci in fetal brains depends on the imaging modality used and the gestational age at imaging. Information regarding sulcal visualization may aid in counseling patients carrying fetuses with ventriculomegaly.

Magnetic resonance volumetric assessments of brains in fetuses with ventriculomegaly correlated to outcomes

OBJECTIVES

The purpose of this study was to correlate 2-dimensional magnetic resonance (MR) measurements of lateral ventricular width and 3-dimensional measurements of lateral ventricular and supratentorial parenchymal volumes to postnatal outcomes in fetuses with ventriculomegaly.

METHODS

A total of 307 fetuses (mean gestational age, 26.0 weeks; range, 15.7-39.4 weeks) had MR volumetry after referral for ventriculomegaly. Fetuses were grouped into those with (n = 114) and without (n = 193) other central nervous system (CNS) anomalies. Pregnancy and postnatal neurodevelopmental outcomes up to 3 years of age were obtained. A subgroup analysis was performed excluding fetuses with other CNS anomalies. Logistic regression analysis was performed to assess which measurement was most predictive of outcomes.

RESULTS

There were 50 terminations, 2 stillbirths, and 255 live births. Seventy-five cases were lost to follow-up. Among 180 live-born neonates with follow-up, 140 had abnormal and 40 had normal outcomes. Atrial diameter (P < .0001), frontal horn diameter (P < .0001), and ventricular volume (P = .04) were predictive of live birth, with 92% specificity at 60% sensitivity. Among fetuses without other CNS anomalies, 180 of 193 pregnancies (93%) resulted in live deliveries, with atrial diameter (P < .0001), frontal horn diameter (P = .003), and ventricular volume (P = .008) associated with live birth and atrial diameter having the highest specificity (>99% at 60% sensitivity). Parenchymal volume was not associated with normal or abnormal outcomes (either live birth versus death or normal versus abnormal neurodevelopmental outcome). Among live-born neonates, no age-adjusted threshold for any of the measurements reliably distinguished between normal and abnormal neurodevelopmental outcomes.

CONCLUSIONS

Ventricular volume and diameter, but not parenchymal volume, correlate with live birth in fetuses with ventriculomegaly. However, once live born, neither 2- nor 3-dimensional measurements can distinguish a fetus that will have a normal outcome.

Outcome of fetuses with cerebral ventriculomegaly and septum pellucidum leaflet abnormalities

OBJECTIVE

The objective of this study was to assess the outcomes of the prenatal diagnosis of septal leaflet abnormalities in fetuses referred for prenatal imaging with a finding of ventriculomegaly.

MATERIALS AND METHODS

This study is a retrospective review of fetuses with a diagnostic code of septal leaflet abnormalities from a larger prospective study. Four hundred twenty-five pregnant women with 433 fetuses referred for ventriculomegaly were imaged with ultrasound and MRI between July 1, 2003, and May 15, 2009. Four to six radiologists independently reviewed sonographic and MR images and recorded lateral ventricular diameters at the atrium and frontal horns, ventricular configuration, and the presence of ventriculomegaly and of other CNS abnormalities. Final prenatal ultrasound, MRI, and overall diagnoses were decided by consensus. Fetuses with a diagnostic code of septal leaflet abnormalities were identified, and birth outcome, autopsy findings, postnatal imaging, and postnatal follow-up examinations were obtained. The analysis of covariance, controlling for gestational age, was used to compare ventricular dimensions between fetuses with septal leaflet abnormalities and fetuses with isolated ventriculomegaly. Interrater agreement for the detection of septal leaflet abnormalities was assessed with kappa statistics. Interrater agreement and intrarater agreement for frontal horn measurements were assessed by variance components analysis.

RESULTS

Twenty-three fetuses had septal leaflet abnormalities and 229 had isolated ventriculomegaly. Atrial and frontal horn diameters, adjusted for gestational age, were 77% and 98% larger, respectively, in fetuses with septal leaflet abnormalities than in fetuses with isolated ventriculomegaly (p < 0.0001). Before the consensus conference, agreement among ultrasound readers was moderate (κ = 0.54) and among MR readers, good (κ = 0.69). Additional CNS findings were seen on MRI in 12 of 23 fetuses (52%). Eleven pregnancies with septal leaflet abnormalities underwent termination and 12 progressed to livebirth; of the 12 livebirths, three neonates died. Neurodevelopmental follow-up was abnormal in all surviving children.

CONCLUSION

A septal leaflet abnormality in the setting of ventriculomegaly is most frequently associated with other CNS abnormalities and is associated with postnatal developmental delay.

Magnetic resonance imaging of the fetus

Fetal magnetic resonance imaging (MRI) has become established as part of clinical practice in many centres worldwide especially when visualization of the central nervous system pathology is required. In this review we summarize the recent literature and provide an overview of fetal development and the commonly encountered fetal pathologies visualized with MRI and illustrated with numerous MR images. We aim to convey the role of fetal MRI in clinical practice and its value as an additional investigation alongside ultrasound yet emphasize the need for caution when interpreting fetal MR images especially where experience is limited.

The role of magnetic resonance imaging in the diagnostic work-up of fetal ventriculomegaly

The indication for fetal magnetic resonance imaging (MRI) remains a subject of debate, partly because of questions concerning its diagnostic accuracy compared to ultrasound, partly because of practical factors such as accessibility, high costs and available expertise. Most studies advocate an added value for MRI in cases diagnosed with central nervous system pathology. MRI is a good modality to detect small foci of brain hemorrhage, to depict callosal anomalies, to add information about normal and pathological cortical development, and is a more sensitive imaging method to detect white matter pathology. This manuscript discusses the role of MRI as an adjunct to ultrasound for cases diagnosed-- with cerebral ventriculomegaly.

Frequency and cause of disagreements in imaging diagnosis in children with ventriculomegaly diagnosed prenatally

OBJECTIVES

To assess the frequency and cause of variability in diagnosis on cranial sonography and magnetic resonance imaging (MRI) in children referred following prenatal diagnosis of ventriculomegaly.

METHODS

Between 19 September 2003 and 16 March 2007, 119 infants with ultrasound and/or MRI studies performed within 13 months (median, 6 days) after birth, following prenatal referral for ventriculomegaly, were studied prospectively. There were 97 infants with ultrasound results and 53 with MRI, including 31 with both. Three sonologists and three pediatric neuroradiologists interpreted the postnatal ultrasound and MRI findings, blinded to prenatal diagnosis, and a final consensus diagnosis or group of diagnoses was obtained. Ventricular sizes as well as types of and reasons for any disagreement in diagnosis were recorded. Disagreements on a per patient basis were categorized as being major when they crossed diagnostic categories and had the potential to change patient counseling. Postnatal and prenatal diagnoses were compared.

RESULTS

There was prospective agreement on 42/97 (43%) ultrasound and on 9/53 (17%) MRI readings. Prospective consensus was more likely when the number of central nervous system (CNS) anomalies was lower (P < 0.001 and P = 0.002 for ultrasound and MRI, respectively). In 24/55 (44%) ultrasound and 11/44 (25%) MRI examinations with disagreement in diagnosis, there was disagreement concerning the presence of ventriculomegaly. In 22/97 (23%) ultrasound studies and 22/53 (42%) MRI studies the disagreements were potentially important. Reasons for discrepancies in the reporting of major findings included errors of observation as well as modality differences in depiction of abnormalities. In comparing prenatal with postnatal diagnoses, there were 11/97 (11%) ultrasound and 27/53 (51%) MRI examinations with newly detected major findings, the most common being migrational abnormalities, callosal dysgenesis/destruction and interval development of hemorrhage.

CONCLUSION

Variability in postnatal CNS diagnosis is common after a prenatal diagnosis of ventriculomegaly. This is due in part to a lack of standardization in the definition of postnatal ventriculomegaly.

Prenatal treatment for serious neurological sequelae of congenital toxoplasmosis: an observational prospective cohort study

BACKGROUND

The effectiveness of prenatal treatment to prevent serious neurological sequelae (SNSD) of congenital toxoplasmosis is not known.

METHODS AND FINDINGS

Congenital toxoplasmosis was prospectively identified by universal prenatal or neonatal screening in 14 European centres and children were followed for a median of 4 years. We evaluated determinants of postnatal death or SNSD defined by one or more of functional neurological abnormalities, severe bilateral visual impairment, or pregnancy termination for confirmed congenital toxoplasmosis. Two-thirds of the cohort received prenatal treatment (189/293; 65%). 23/293 (8%) fetuses developed SNSD of which nine were pregnancy terminations. Prenatal treatment reduced the risk of SNSD. The odds ratio for prenatal treatment, adjusted for gestational age at maternal seroconversion, was 0.24 (95% Bayesian credible intervals 0.07-0.71). This effect was robust to most sensitivity analyses. The number of infected fetuses needed to be treated to prevent one case of SNSD was three (95% Bayesian credible intervals 2-15) after maternal seroconversion at 10 weeks, and 18 (9-75) at 30 weeks of gestation. Pyrimethamine-sulphonamide treatment did not reduce SNSD compared with spiramycin alone (adjusted odds ratio 0.78, 0.21-2.95). The proportion of live-born infants with intracranial lesions detected postnatally who developed SNSD was 31.0% (17.0%-38.1%).

CONCLUSION

The finding that prenatal treatment reduced the risk of SNSD in infected fetuses should be interpreted with caution because of the low number of SNSD cases and uncertainty about the timing of maternal seroconversion. As these are observational data, policy decisions about screening require further evidence from a randomized trial of prenatal screening and from cost-effectiveness analyses that take into account the incidence and prevalence of maternal infection. Please see later in the article for the Editors' Summary.

Neurodevelopmental outcome of fetuses referred for ventriculomegaly

OBJECTIVE

To characterize the delivery and postnatal neurodevelopmental outcomes of fetuses referred for ventriculomegaly (VM).

METHODS

Under an internal review board-approved protocol, pregnant women were referred for magnetic resonance imaging (MRI) after sonographic diagnosis of VM and classified into one of four diagnostic groups: Group 1, normal central nervous system (CNS); Group 2, isolated mild VM (10-12 mm); Group 3, isolated VM > 12 mm; and Group 4, other CNS findings. Pregnancy outcome was obtained. Follow-up visits were offered with assessment of neurodevelopmental, adaptive and neurological functioning at 6 months and 1 year and/or 2 years of age. Atrial diameter and VM group differences in developmental outcomes were evaluated using repeated measures logistic regression and Fishers exact test, respectively.

RESULTS

Of 314 fetuses, 253 (81%) were liveborn and survived the neonatal period. Fetuses in Groups 4 and 3 were less likely to progress to live delivery and to survive the neonatal period (60% and 84%, respectively) than were those in Groups 2 or 1 (93% and 100%, respectively, P < 0.001). Of the 143 fetuses followed postnatally, between 41% and 61% had a Bayley Scales of Infant Development (BSID-II) psychomotor developmental index score in the delayed range (< 85) at the follow-up visits, whereas the BSID-II mental developmental index and Vineland Adaptive Behavior composite scores were generally in line with normative expectations. Among those that were liveborn, neither VM group nor prenatal atrial diameter was related to postnatal developmental outcome.

CONCLUSIONS

Diagnostic category and degree of fetal VM based on ultrasound and MRI measurements are associated with the incidence of live births and thus abnormal outcome. Among those undergoing formal postnatal testing, VM grade is not associated with postnatal developmental outcome, but motor functioning is more delayed than is cognitive or adaptive functioning.

Magnetic resonance imaging of the fetal brain

PURPOSE OF REVIEW

Fetal magnetic resonance imaging (MRI) is a relatively new clinical application but is becoming increasingly used in fetal medicine in combination with the established technique of antenatal ultrasound. A review of the literature to date provides information for clinicians to help assess which patients they should be referring for fetal MRI and what additional information to ultrasound they can obtain.

RECENT FINDINGS

This review covers recent articles on practical aspects of imaging, MR findings in common disorders and comparisons with ultrasound. It includes information on current applications for fetal MRI, new sequence acquisitions and postprocessing techniques. Fetal motion is the single most important barrier to improving image data.

SUMMARY

Fetal MR has become an established tool for assessing the fetal brain. It provides complementary information to ultrasound. However, further optimization of this technique is still required to ensure it is exploited to the full in fetal medicine.

The significance of fetal ventriculomegaly: etiology, short- and long-term outcomes

Fetal cerebral ventriculomegaly (VM) is diagnosed when the width of one or both ventricles, measured at the level of the glomus of the choroid plexus (atrium), is > or = 10 mm. VM can result from different processes: abnormal turnover of the cerebrospinal fluid (CSF), neuronal migration disorders, and destructive processes. In a high percentage of cases, it is associated with structural malformations of the central nervous system (CNS), but also of other organs and systems. The rate of associated malformations is higher (> or =60%) in severe VM (>15 mm) and lower (10-50%) in cases of borderline VM (10-15 mm). When malformations are not present, aneuploidies are found in 3-15% of borderline VM; the percentage is lower in severe VM. The neurodevelopmental outcome of isolated VM is normal in > 90% of cases if the measurement of ventricular width is between 10 and 12 mm; it is less favorable when the measurement is > 12 mm.