Fetal cerebral ventriculomegaly: outcome in 176 cases

Mid-term neurodevelopmental outcome in isolated mild ventriculomegaly diagnosed in fetal life

OBJECTIVE

To analyze mid-term neurodevelopment outcome in children with isolated mild ventriculomegaly (VM) ≤12 mm diagnosed in fetal life, using the Battelle Developmental Inventory Screening Test (BDIST).

METHODS

86 cases of mild VM were identified. 68 were excluded due to: other cerebral anomalies (n = 40), extra-cerebral anomalies (n = 3), chromosomal defects (n = 4), dysmorphic syndromes (n = 4), congenital infections (n = 2), termination of pregnancy (n = 9), stillbirth (n = 2) and incomplete follow-up (n = 4). 18 cases (range 1-8 years) of isolated mild VM were included for analysis. Seven neurodevelopment domains were assessed by BDIST.

RESULTS

Routine neuropediatrical evaluation detected neurological disorders in five children (28%; 3 with language impairment, one left hemiparesis and one intellectual retardation). BDIST showed some degree of neurodevelopmental delay in higher proportions: 66% in social-personal skills, 56% in gross motor skills, 39% in adaptive behavior and 28% in fine motor skills. Communicative and cognitive areas were the least affected (11 and 22% had moderate-to-severe involvement, respectively). A general trend towards worse outcomes was observed in the group of ≥4 years, although significant differences were only found for gross motor skills.

CONCLUSION

Subtle neurological delays may appear during the infant period in fetuses prenatally diagnosed of isolated mild VM. In consequence, adequate measures should be established for early detection and treatment.

Early prenatal ventriculomegaly due to an AIFM1 mutation identified by linkage analysis and whole exome sequencing

The identification of disease causing mutation in patients with neurodegenerative disorders originating from small, non-consanguineous families is challenging. Three siblings were found to have ventriculomegaly at early gestation; postnatally, there was no acquisition of developmental milestones, and the muscles of the children were dystrophic. Plasma and CSF lactate levels were normal, but the activities of mitochondrial complex I and IV were markedly decreased. Using linkage analysis in the family, followed by whole exome sequencing of a single patient, we identified a pathogenic mutation in the AIFM1 gene which segregated with the disease state and was absent in 86 anonymous controls. This is the second report of a mutation in the AIFM1 gene, extending the clinical spectrum to include prenatal ventriculomegaly and underscores the importance of AIF for complex I assembly. In summary, linkage analysis followed by exome sequencing of a single patient is a cost-effective approach for the identification of disease causing mutations in small non-consanguineous families.

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.

Changes of nerve growth factor in amniotic fluid and correlation with ventriculomegaly

OBJECTIVE

To detect the change of nerve growth factor (NGF) level in human amniotic fluid during gestation, and to explore the relationship between this change and fetal ventriculomegaly (VM).

METHODS

The studied subjects (collected from 2004 to 2007) were divided into four groups, including the second-trimester pregnancy group (n=113), third-trimester pregnancy group (n=110), fetal cerebral VM group (n=12), and healthy control group (n=12) which matched with the VM group in gestational weeks. The amniotic fluid specimens were obtained during amniocentesis or cesarean section. The NGF levels in amniotic fluid were detected with enzyme-linked immunosorbent assay.

RESULTS

A significantly negative correlation was found between gestational age and the NGF level in amniotic fluid (r=−0.6149, P<0.0001). The NGF level in patients with fetal VM was significantly lower than that in healthy controls (33.95&plusmn;29.24 pg/mL vs. 64.73&plusmn;16.21 pg/mL, P=0.024).

CONCLUSION

NGF levels in amniotic fluid may be a sensitive marker for fetal VM.

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.

Fetuses with ventriculomegaly diagnosed in the second trimester of pregnancy by in utero MR imaging: what happens in the third trimester?

BACKGROUND AND PURPOSE

Although MR imaging of the fetal brain has been shown to provide additional diagnostic information, the optimal timing of the study and the value of repeat studies remain unclear. The primary purpose of this study was to look for structural abnormalities of the fetal brain shown at 30-32 weeks' gestational age but not on the 20-24 weeks' study in fetuses originally referred with isolated VM. In particular, we wished to study the hypothesis that third-trimester fetal MR imaging studies would not show extra brain abnormalities compared with the second-trimester studies in this group.

MATERIALS AND METHODS

Ninety-nine women were admitted for a fetal MR study between 20-24 weeks' gestational age, and 46 of these women agreed to return for a second MR imaging examination at 30-32 weeks' gestational age. The other women were either lost to follow-up or declined the invitation to return. Two experienced observers measured the width of the trigones, and the results were compared, to test reliability. Changes in the degree of VM are reported along with changes in the diagnosis of structural brain abnormalities.

RESULTS

There was excellent reproducibility of trigone measurements between the 2 observers, with a mean absolute difference of <1 mm in the 40 fetuses that were ultimately shown to have isolated VM. Twenty-eight of 40 fetuses studied had mild VM on the first iuMR imaging examination, but in just more than half, the category of VM changed between the studies (5 had become normal-sized, 7 had progressed to moderate, 3 had become severe, and 13 remained mild). In 1 case, hypogenesis of the corpus callosum was recognized at 30-32 weeks but had not been reported on the 20-24 weeks' examination; the other 5 fetuses had brain pathology recognized on both fetal MR studies.

CONCLUSIONS

Trigone measurements can be made in a highly repeatable fashion on iuMR imaging. We have not shown any major advantage in repeating iuMR imaging at 30-32 weeks' gestation in terms of improved diagnosis of other structural brain abnormalities. With the converse of that argument, however, our data suggest that there is no advantage in delaying iuMR imaging studies to 30-32 weeks in the hope of improving detection rates.

Morphological evaluation of lateral ventricles of fetuses with ventriculomegaly by three-dimensional ultrasonography and magnetic resonance imaging: correlation with etiology

PURPOSE

To evaluate morphology of lateral ventricles of ventriculomegaly/hydrocephaly fetuses using 3D-sonography by virtual organ computer-aided analysis (VOCAL) technique and magnetic resonance imaging (MRI) and verify morphologic patterns related to etiology.

METHODS

Seventeen fetuses presenting with ventricular enlargement (atria > 10 mm) were evaluated. 3D datasets were acquired from a coronal reference plane and post-processed by the rotational imaging using VOCAL 30°. MRI study was analyzed in the three plans in all sequences. Morphologic aspects such as global shape, anterior, posterior and inferior horn characteristics, wall irregularities and deformities were analyzed and related to etiology factor.

RESULTS

Twenty-nine percent of the cases were secondary to Arnold-Chiari syndrome and presented with global dilation of the three-horns. Cases related to aqueduct stenosis presented with ependymal rupture and wall irregularities in advanced cases. Corpus callosum agenesis cases presented with small ventricular volumes, thin shape, normal or slightly enlarged anterior and inferior horns with dilation restricted to posterior horn. Cases related to trisomy 18 and cytomegalovirus presented irregular ventricular walls associated with anomalous ventricular shapes, suggesting parenchymal destruction.

CONCLUSION

Ventricular morphology evaluation gives important information on etiology of ventricular enlargement, supporting prognosis prediction and decision making process of the affected fetuses and their families.

Prognosis of isolated mild to moderate fetal cerebral ventriculomegaly: a systematic review

AIMS

To ascertain risk of aneuploidy, infection and neurological abnormality for the fetus diagnosed with isolated mild (10.1-12.0 mm) to moderate (12.1-15.0 mm) cerebral ventriculomegaly and to compare the neurological outcome between symmetrical vs. asymmetrical and stable vs. progressive ventriculomegaly.

METHODS

A systematic review was conducted. Literature was identified by searching two bibliographical databases between 1980 and 2009 without language restrictions. The data extracted were inspected for heterogeneity. Overall rates and confidence intervals (CIs) for each prognostic factor were calculated. When comparative data existed, the odds ratio (OR) was calculated.

RESULTS

The search strategy yielded 2150 relevant citations of which 28 studies were included in the review. The overall rate of infection and chromosomal abnormality was 1.5 and 5% (95% CI 3, 7), respectively. The risk of neurological abnormality regardless of karyotype or infection screen was 14% (95% CI 10, 18) and this reduced to 12% (95% CI 9, 15) when both chromosomes and infection screen were normal. The risk of neurological abnormality was significantly lower in stable compared to progressive ventriculomegaly [OR 0.29 (95% CI 0.15, 0.58)]. No significant differences were detected when symmetrical vs. asymmetrical ventriculomegaly were compared [OR 0.91 (95% CI 0.34, 2.41)].

CONCLUSION

This systematic review provides the physician with some estimates of prognosis in cases of isolated mild to moderate ventriculomegaly.

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.

MR imaging of the fetal brain

Fetal MRI is clinically performed to evaluate the brain in cases where an abnormality is detected by prenatal sonography. These most commonly include ventriculomegaly, abnormalities of the corpus callosum, and abnormalities of the posterior fossa. Fetal MRI is also increasingly performed to evaluate fetuses who have normal brain findings on prenatal sonogram but who are at increased risk for neurodevelopmental abnormalities, such as complicated monochorionic twin pregnancies. This paper will briefly discuss the common clinical conditions imaged by fetal MRI as well as recent advances in fetal MRI research.

Agenesis of the corpus callosum in fetuses with mild ventriculomegaly: role of MR imaging

PURPOSE

We evaluated the role of magnetic resonance (MR) imaging in the diagnosis of corpus callosum agenesis - isolated or associated with other anomalies - in fetuses with mild cerebral ventriculomegaly, as depicted at prenatal sonography.

MATERIAL AND METHODS

Between January 2005 and March 2007, 33 fetuses with a mean gestational age of 28.9 weeks (range 17-37) and mild ventriculomegaly diagnosed at prenatal sonography were included in this prospective study. All fetuses underwent MR imaging according to the following protocol: half-Fourier T2-weighted images along the three orthogonal plane according to the longitudinal axis of the mother, and subsequently three orthogonal planes were acquired according to the fetal brain. Quantitative image analysis included the size of the transverse diameter of the lateral ventricles, in the axial plane, and the thickness of the adjacent cerebral cortex. Qualitative image analysis included morphology of the lateral ventricles (normal, parallel pattern colpocephaly), signal intensity changes of the fetal brain, interruption of the germinative matrix, agenesis of the corpus callosum (complete/partial) and associated malformations. Postnatal physical examination and diagnostic imaging, as well as surgery, were the standard of diagnosis.

RESULTS

Mean axial diameter of the lateral ventricle was 11.6 mm (range 10-15 mm), and mean thickness of the adjacent cerebral cortex was 2.1 mm (range 1.8-3 mm); 23/33 fetuses (70%) showed normal morphology of the lateral ventricles, and 8/33 (24%) showed abnormal morphology (parallel pattern, colpocephaly). The entire corpus callosum was visualised in 20/33 fetuses (60%). In 8/33 fetuses (25%), partial agenesis was diagnosed, whereas in 5/33 (15%), there was hypogenesis. In 6/13 fetuses (46%), isolated corpus callosum agenesis was detected, and two cases of hypogenesis of the corpus callosum were misinterpreted - overestimated in one case and underestimated in another.

CONCLUSIONS

MR imaging may prove to be a useful second-line imaging modality in the prenatal diagnosis of corpus callosum agenesis in fetuses with mild ventriculomegaly.

High-frequency oscillatory ventilation is not associated with increased risk of neuropathology compared with positive pressure ventilation: a preterm primate model

High-frequency oscillatory ventilation (HFOV) may improve pulmonary outcome in very preterm infants, but the effects on the brain are largely unknown. We hypothesized that early prolonged HFOV compared with low volume positive pressure ventilation (LV-PPV) would not increase the risk of delayed brain growth or injury in a primate model of neonatal chronic lung disease. Baboons were delivered at 127 +/- 1 d gestation (dg; term approximately 185 dg), ventilated for 22-29 d with either LV-PPV (n = 6) or HFOV (n = 5). Gestational controls were delivered at 153 dg (n = 4). Brains were assessed using quantitative histology. Body, brain, and cerebellar weights were lower in both groups of prematurely delivered animals compared with controls; the brain to body weight ratio was higher in HFOV compared with LV-PPV, and the surface folding index was lower in the LV-PPV compared with controls. In both ventilated groups compared with controls, there was an increase in astrocytes and microglia and a decrease in oligodendrocytes (p < 0.05) in the forebrain and a decrease in cerebellar granule cell proliferation (p < 0.01); there was no difference between ventilated groups. LV-PPV and HFOV ventilation in prematurely delivered animals is associated with decreased brain growth and an increase in subtle neuropathologies; HFOV may minimize adverse effects on brain growth.

Diagnostic performance of routine ultrasound screening for fetal abnormalities in an unselected Swedish population in 2000-2005

OBJECTIVES

To determine the detection rate of fetal malformations and chromosomal abnormalities and the rate of false-positive ultrasound diagnoses at routine ultrasound examinations carried out by specially trained midwives in an unselected pregnant population from 2000 to 2005, and to describe the consequences of true-positive and false-positive ultrasound diagnoses of fetal malformations.

METHODS

A retrospective analysis was undertaken of all babies born in Malmö, Sweden, between January 2000 and December 2005 by mothers residing in Malmö and of all fetuses with an ultrasound diagnosis of malformation made in the same time interval at the two units performing all routine pregnancy scans in Malmö. All women underwent two routine scans, at 18 and 32 weeks, including scrutiny of the fetal anatomy. Detection rates and false-positive rates were calculated per fetus.

RESULTS

The prevalence of chromosomally abnormal fetuses was 0.31% (52/16 775); that of chromosomally normal fetuses with major and minor malformations was 1.80% (302/16 775) and 1.32% (222/16 775), respectively. The detection rate of fetuses with major malformations but normal chromosomes was 68% (205/302), with a detection rate at < 22 weeks of 37% (112/302). In addition, 46% (24/52) of all chromosomally abnormal fetuses were diagnosed before birth because a malformation was detected at ultrasound imaging, 33% (17/52) being detected at < 22 gestational weeks. In all, 68 pregnancies were terminated because of an ultrasound diagnosis of fetal malformation (0.4% of all pregnancies and 47% of the pregnancies in which a fetal malformation was detected by ultrasound examination before 22 weeks). A false-positive ultrasound diagnosis of malformation was made in 0.19% (31/16 180) of the normally formed fetuses and in 20 (0.12%) fetuses the abnormal finding persisted during pregnancy. No fetus assigned a false-positive diagnosis was lost by termination of pregnancy, but most were subjected to one or more unnecessary interventions before birth (e.g. amniocentesis), at birth (e.g. Cesarean section) or after birth (e.g. electrocardiogram, X-ray, ultrasound examination or treatment with antibiotics).

CONCLUSIONS

In a screening program consisting of one fetal anomaly scan at 18 weeks and another at 32 weeks the detection rate of major malformations in chromosomally normal fetuses was 68% with a detection rate of 37% at < 22 weeks. The corresponding detection rates of chromosomally abnormal fetuses were 46% and 33%. Fewer than one in 500 screened fetuses had an ultrasound diagnosis of an anomaly that was not confirmed after birth.

A prospective study of fetuses with isolated ventriculomegaly investigated by antenatal sonography and in utero MR imaging

BACKGROUND AND PURPOSE

Fetal ventriculomegaly (VM) is important because of its high prevalence and high risk of association with other brain abnormalities. The purpose of this article was to investigate the hypotheses that including in utero MR imaging (iuMR) in the diagnostic pathway for fetuses with isolated VM on antenatal imaging will show other brain abnormalities in a high proportion of cases and that these will have a significant effect on clinical management.

MATERIALS AND METHODS

One hundred forty-seven pregnant women were recruited prospectively from 8 fetomaternal centers in Britain. All of the fetuses had VM diagnosed on sonography but no other abnormality. iuMR was performed, and the results of the examinations were compared with those of sonography. Two fetomaternal experts made independent assessments of the effects of any new diagnoses on clinical management.

RESULTS

Categoric assessments of ventricular size were the same in approximately 90% of fetuses. Other abnormalities were shown in 17% of fetuses. The most frequent additional brain abnormality shown on iuMR was agenesis of the corpus callosum. Severe VM was associated with an approximately 10-fold increase in the risk of another brain abnormality being present when compared with fetuses with mild VM. The most profound effects on clinical management, however, were found in cases of mild VM.

CONCLUSIONS

This work supports our hypotheses by showing a high detection rate of other brain pathology when iuMR was used to supplement antenatal sonography (17%). In a high proportion of cases, the detection of the extra pathology would have led to significant changes in clinical management.

Fetal magnetic resonance imaging of acquired and developmental brain anomalies

During the last decade, increasing interest in magnetic resonance imaging has emerged for the evaluation of fetal abnormalities detected on ultrasound. The advent of single-shot rapid acquisition sequences has greatly facilitated our ability to obtain detailed imaging information of the fetal brain. To date, fetal magnetic resonance imaging has shown to have an important role in the investigation of cerebral abnormalities suspected by sonography, and in the detection of subtle brain anomalies associated with high-risk pregnancies. Magnetic resonance imaging has proved to be a useful adjunct to sonography during the prenatal period of development, especially for the detection of acquired disorders.

Counseling in isolated mild fetal ventriculomegaly

In this Review we aim to provide up-to-date and evidence-based answers to the common questions regarding the diagnosis of isolated mild fetal ventriculomegaly (VM). A literature search was performed to identify all reports of antenatal VM in the English language literature. In addition, reference lists of articles identified using the search were scrutinized to further identify relevant articles. Fetal mild VM is commonly defined as a ventricular atrial width of 10.0-15.0 mm, and it is considered isolated if there are no associated ultrasound abnormalities. There is no good evidence to suggest that the width of the ventricular atria contributes to the risk of neurodevelopmental outcome in fetuses with mild VM. The most important prognostic factors are the association with other abnormalities that escape early detection and the progression of ventricular dilatation, which are reported to occur in about 13% and 16% of cases, respectively. Most infants with a prenatal diagnosis of isolated mild VM have normal neurological development at least in infancy. The rate of abnormal or delayed neurodevelopment in infancy is about 11%, and it is unclear whether this is higher than in the general population. Furthermore, the number of infants that develop a real handicap is unknown. There are limitations of existing studies of mild VM. Although they address many of the relevant questions regarding the prognosis and management of fetal isolated mild VM, there is a lack of good-quality postnatal follow-up studies. The resulting uncertainties make antenatal counseling for this abnormality difficult.

The neurocognitive outcome of mild isolated fetal ventriculomegaly verified by prenatal magnetic resonance imaging

OBJECTIVE

Neurocognitive outcome of preschool children, prenatal diagnosis of isolated mild ventriculomegaly compared with 2 control groups.

STUDY DESIGN

Case-controlled study at the University Hospital of Tel Aviv between October 1999 and December 2002. Study groups consisted of 12 children with bilateral isolated mild ventriculomegaly, and 16 children with unilateral isolated mild ventriculomegaly, mean age 4.4 years, prenatally diagnosed by both ultrasound and fetal magnetic resonanace imaging. Control groups consisted of 16 children with normal prenatal magnetic resonance imaging and 16 regular kindergarten children. A neurodevelopmental examination and the Kaufman Assessment Battery for Children were performed.

RESULTS

The neurodevelopmental and Kaufman scores were within normal range in the study groups. No significant differences between the study and control groups for most measures; however, Kaufman achievement score was significantly lower for the bilateral isolated mild ventriculomegaly group (P < .05) compared with the kindergarten children.

CONCLUSION

Preschool children with isolated mild ventriculomegaly performed within normal range compared with the controls. Nevertheless, a significant percentage of the children demonstrated developmental difficulties, lower achievement scores, justifying early school years follow-up.

Perinatal and neurodevelopmental outcome with isolated fetal ventriculomegaly: A systematic review

OBJECTIVE

To establish the perinatal and neurodevelopmental outcomes of fetuses diagnosed with isolated ventriculomegaly (IVM).

METHODS

A systematic review of cohort, case/control studies, case series and case reports of IVM (unilateral or bilateral enlargement of the lateral ventricle, >or=10 mm, with no additional diagnosis at the time of the initial ultrasound), identified by searching, without language restrictions, The Cochrane Library, MEDLINE and Embase databases in June 2004.

RESULTS

No cohort study was retrieved but 577 cases were identified in one case/control study and 29 case series/case reports. Of 207 cases with follow-up and known gestational age at diagnosis, normal developmental outcomes were found in 82%, mild impairments in 9% and moderate/severe impairments in 10%. Prenatal diagnosis could possibly have reduced the risk of moderate/severe impairments to 7%. In 137 cases followed to at least 20 months of age, 79% had normal neurodevelopment, 10% were mildly delayed and 11% had moderate/severe developmental delays.

CONCLUSIONS

Outcome was favorable in 85% of IVM cases, decreasing to 79% when cases were followed to at least 20 months of age. We recommend prospective cohort studies with new diagnostic modalities to better identify the underlying conditions relating to moderate/severe impairments in the remaining cases.

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.

Normal sonographic development of the central nervous system from the second trimester onwards using 2D, 3D and transvaginal sonography

The developmental changes of the fetal central nervous system (CNS) during the second and third trimesters, specifically the brain, relate mostly to changes in size. However, other changes do occur in the fetal brain during the second and third trimester such as: the union of the cerebellar hemispheres, development of the corpus callosum (CC), and increasing complexity of the cerebral cortex. These changes follow a well-defined developmental timeline recognizable by sonography. The fetal neuroscan can be divided into a 'basic scan' which is performed transabdominally and a 'targeted Exam or neurosonogram' which uses a multiplanar approach, which preferably should be performed transvaginally. During the 'basic scan', several brain structures are imaged in addition to obtaining important biometric measurements. The 'neurosonogram' is a more extensive or detailed fetal study during which the emphasis is on the addition of coronal and sagittal planes. The easiest way to obtain these planes, if the fetus is in a cephalic presentation, is the transvaginal route. Three-dimensional (3D) sonography should, if possible, be performed transvaginally using the multiplanar approach. An added benefit of 3D sonography is the ability to display and render the volume in a variety of ways which may enhance the detection of pathology.

MRI of the fetal central nervous system and body

MRI is being increasingly used to assess for fetal abnormalities. Although significant progress in the field of fetal MRI has occurred during the past 20 years, continued technical advances will likely contribute to significant growth of the field. Moreover, with continued hardware and software improvements, additional MRI sequences will likely become available. Prenatal MRI complements ultrasound because of larger field-of-view, superior soft tissue contrast, easier and more precise volumetric measurement, and greater accuracy in the demonstration of intracranial and spinal abnormalities. While ultrasound remains the primary modality for fetal imaging, these advantages of MRI make it a valuable adjunct to fetal surgery. Because fetal MRI involves many disciplines, the future of fetal MR will best be achieved through collaborative efforts.

Prenatal mild ventriculomegaly predicts abnormal development of the neonatal brain

BACKGROUND

Many psychiatric and neurodevelopmental disorders are associated with mild enlargement of the lateral ventricles thought to have origins in prenatal brain development. Little is known about development of the lateral ventricles and the relationship of prenatal lateral ventricle enlargement with postnatal brain development.

METHODS

We performed neonatal magnetic resonance imaging on 34 children with isolated mild ventriculomegaly (MVM; width of the atrium of the lateral ventricle >/= 1.0 cm) on prenatal ultrasound and 34 age- and sex-matched control subjects with normal prenatal ventricle size. Lateral ventricle and cortical gray and white matter volumes were assessed. Fractional anisotropy (FA) and mean diffusivity (MD) in corpus callosum and corticospinal white matter tracts were determined obtained using quantitative tractography.

RESULTS

Neonates with prenatal MVM had significantly larger lateral ventricle volumes than matched control subjects (286.4%; p < .0001). Neonates with MVM also had significantly larger intracranial volumes (ICV; 7.1%, p = .0063) and cortical gray matter volumes (10.9%, p = .0004) compared with control subjects. Diffusion tensor imaging tractography revealed a significantly greater MD in the corpus callosum and corticospinal tracts, whereas FA was significantly smaller in several white matter tract regions.

CONCLUSIONS

Prenatal enlargement of the lateral ventricle is associated with enlargement of the lateral ventricles after birth, as well as greater gray matter volumes and delayed or abnormal maturation of white matter. It is suggested that prenatal ventricle volume is an early structural marker of altered development of the cerebral cortex and may be a marker of risk for neuropsychiatric disorders associated with ventricle enlargement.

Postnatal clinical and imaging follow-up of infants with prenatal isolated mild ventriculomegaly: a series of 101 cases

BACKGROUND

Postnatal imaging and clinical outcome of fetuses with isolated mild ventriculomegaly (IMV) have never been systematically analysed.

OBJECTIVE

To evaluate the postnatal clinical outcomes of a large cohort of fetuses with IMV and to correlate them with pre- and postnatal imaging.

MATERIALS AND METHODS

We report a prospective study of 101 fetuses with IMV (10-15 mm ventriculomegaly with otherwise normal US, MRI, karyotype and TORCH screening). IMV was divided into minor (10-11.9 mm) and moderate (12-15 mm) ventriculomegaly. Ventriculomegaly was considered uni- or bilateral, stable, progressive, regressive or resolved according to the prenatal US follow-up. Clinical follow-up was performed by a neuropaediatrician. Postnatal imaging included cranial US (n = 71) and MRI (n = 76).

RESULTS

The outcome of minor and moderate IMV was excellent in 94% and 85% of infants, respectively. It was not different between uni- and bilateral IMV, and between stable, regressive and resolved IMV, and was independent of gestational age at diagnosis and gender. Fixed neurological abnormalities were observed in nine infants. Postnatal MRI showed white-matter abnormalities in 14 infants, including 6 of the 9 infants with a poor outcome.

CONCLUSION

The prognosis was slightly better in minor IMV than in moderate IMV. Postnatal MRI showed white-matter abnormalities in two-thirds of the infants with a poor outcome.

MR volumetry of brain and CSF in fetuses referred for ventriculomegaly

OBJECTIVE

The purpose of this study was to validate the method of performing fetal brain volumetry. In particular, our objectives were to assess which imaging plane is most reproducible for the performance of brain volumetry measurements and to ascertain inter- and intraobserver variability in determining brain volume in fetuses referred for ventriculomegaly (VM).

SUBJECTS AND METHODS

In this prospective study, 50 consecutive fetuses at 17-37 weeks of gestational age referred for MRI for VM underwent fast spin-echo T2-weighted imaging. Supratentorial brain parenchyma, lateral ventricles, and extraaxial and cerebellar volumetric measurements were manually obtained in three planes by three radiologists. Inter- and intraobserver variability were assessed. The relationship between volumes and gestational age, and lateral ventricular diameter were assessed.

RESULTS

Volumes increased with gestational age. The presence of VM correlated with increased lateral ventricle diameter. The effect of imaging plane was negligible. Inter- and intraobserver variability were low.

CONCLUSION

Supratentorial parenchyma and lateral ventricular volumes can be reliably measured on fetal MRI, and imaging plane was not an important factor in measurement. Further studies are needed to correlate these indexes with long-term postnatal outcomes.

Reference ranges for fetal ventricular width: a non-normal approach

OBJECTIVES

Normal ranges for fetal cerebral ventricular width are usually based on parametric methods, which define cut-off values based on means and standard deviations. We aimed to construct reference charts based on a large sample and using a method that better fits with skewed measurements.

METHODS

In November 2001-December 2005, a single operator, who was unaware of the subsequent analysis, performed prospectively and routinely fetal cerebral ventricular width measurements. We used the LMS method (which summarizes the changing distribution of a variable of interest according to a covariate (gestational age) using three curves representing the median (M), the coefficient of variation (S) and skewness (L)) to describe the distribution of measurements with gestational age. The LMS method provides a general method for fitting smooth centile curves to reference data. It utilizes the power transformation family of Box and Cox to allow the skewness of the measurement distribution, as well as the median and variability, to vary with age. The theoretical proportion of fetal ventricular widths > or = 10 mm based on the LMS method and on methods based on the assumption of normality were compared with the actual proportion using binomial tests. The influence on ventricular size of gestational age and fetal gender and presentation was assessed using robust regression methods.

RESULTS

Included in the study were 4769 ventricular measurements, 42 (0.88%) of which were > or = 10 mm. The LMS method allowed us to fit the skewness of the measurements and identified slight changes throughout gestation. The actual proportion of measurements > or = 10 mm was not different from that expected according to the LMS method (0.88% vs. 1%, P = 0.25), whereas it was significantly different from that based on the classical normal approximation (0.88% vs. 0.4%, P < 0.0001). There was a significant difference with gender (males: + 0.29 +/- 0.042 mm as compared to females, P < 0.0001), but there was no difference with fetal presentation (P = 0.4).

CONCLUSION

We present new reference values for fetal ventricular width based on the LMS method. A fixed cut-off value of 10 mm identifies around 1% of the population throughout gestation, which is more than that calculated in previous studies.

Currarino syndrome shown by prenatal onset ventriculomegaly and spinal dysraphism

The most frequent cause of ventriculomegaly is spina bifida when associated with Arnold-Chiari type II malformation. We report on a prenatal diagnosis of severe ventriculomegaly in association with spinal dysraphism that was indicative of a Currarino syndrome (CS) due to a c.584delA, p.H195fsX28 truncated mutation within the HLXB9 gene. Physiopathology of the ventriculomegaly is discussed in reference to the fetopathological examination and CS embryopathology. In the present case, prognosis was poor and pregnancy termination was authorized. However, such a decision may be controversial in fetuses with less severe malformations on sonographic examination, since mutations in the HLXB9 gene can predict neither the severity nor the long-term prognosis of the disease. Due to a lack of genotype-phenotype correlation and the broad variability of phenotype in heterozygotes, clinical and genetic investigations among relatives are mandatory in all HLXB9 gene mutation cases, to detect asymptomatic CS cases and to prevent the occurrence of severe complications.

The value of in-utero magnetic resonance imaging in ultrasound diagnosed foetal isolated cerebral ventriculomegaly

AIM

To assess whether magnetic resonance imaging (MRI) is a useful adjunct to ultrasound (US) when imaging cases of foetal isolated cerebral ventriculomegaly. To assess whether, in such cases, ventricular morphology is a useful indicator for the underlying pathology, as has recently been suggested.

MATERIALS AND METHODS

A retrospective analysis was undertaken of 30 cases of isolated ventriculomegaly diagnosed using US and referred for in utero MRI. The gestational age of each case was noted and the MRI report. Both ventricles were measured and each case was categorized according to severity and morphology. The MRI report was compared to the final diagnosis.

RESULTS

Of the 30 cases evaluated 18 had mild ventriculomegaly (<15 mm; gestational age range 20-31 weeks, mean 22.8, median 22) and 12 had severe ventriculomegaly (>15 mm; gestational age range 21-37 weeks, mean 28, median 28.5). Additional abnormalities were found in 50% of cases overall (44% mild, 58% severe) using MRI.

CONCLUSIONS

Using MRI additional abnormalities were identified in 50% of the foetuses. The morphology of the cases did not suggest underlying pathology in this group. In utero MRI is a useful adjunct to US in cases of foetal cerebral ventriculomegaly referred after initial diagnosis using US.

White matter injury correlates with hypertonia in an animal model of cerebral palsy

Hypertonia and postural deficits are observed in cerebral palsy and similar abnormalities are observed in postnatal rabbits after antenatal hypoxia-ischemia. To explain why some kits become hypertonic, we hypothesized that white matter injury was responsible for the hypertonia. We compared newborn kits at postnatal day 1 (P1) with and without hypertonia after in vivo global fetal hypoxia-ischemia in pregnant rabbits at 70% gestation. The aim was to examine white matter injury by diffusion tensor magnetic resonance imaging indices, including fractional anisotropy (FA). At P1, FA and area of white matter were significantly lower in corpus callosum, internal capsule, and corona radiata of the hypertonic kits (n=32) than that of controls (n=19) while nonhypertonic kits (n=20) were not different from controls. The decrease in FA correlated with decrease in area only in hypertonia. A threshold of FA combined with area identified only hypertonic kits. A reduction in volume and loss of phosphorylated neurofilaments in corpus callosum and internal capsule were observed on immunostaining. Concomitant hypertonia with ventriculomegaly resulted in a further decrease of FA from P1 to P5 while those without ventriculomegaly had a similar increase of FA as controls. Thus, hypertonia is associated with white matter injury, and a population of hypertonia can be identified by magnetic resonance imaging variables. The white matter injury manifests as a decrease in the number and density of fiber tracts causing the decrease in FA and volume. Furthermore, the dynamic response of FA may be a good indicator of the plasticity and repair of the postnatal developing brain.

Obstetric and neonatal outcomes in severe fetal ventriculomegaly

OBJECTIVE

To determine the early outcome and the incidence of associated structural anomalies in pregnancies complicated by severe fetal ventriculomegaly (VM).

METHODS

A review of cases of severe fetal VM (posterior horn of lateral ventricle > 15 mm at referral or during prenatal follow-up) referred to a fetal medicine centre in Eastern England over 4 years from 2001 was made. Results of specialist prenatal investigations including ultrasound (US), karyotype, antiplatelet antibodies and congenital infection screen were noted. Neonatal clinical and cranial US findings, autopsy findings and neurodevelopmental follow-up at 4 months were obtained.

RESULTS

Twenty cases of severe VM were identified, including 3 with spina bifida. Median gestation at diagnosis was 28 weeks (range 16-36 weeks). Twelve cases had additional intra-cranial abnormalities and two had abnormalities outside the central nervous system. One case was complicated by toxoplasmosis. There was one case of trisomy 21. Ten pregnancies were terminated. Ten babies were live born, all of whom had VM confirmed, and two of these babies died within 4 months. Of the remaining eight, seven have abnormal neurodevelopment.

CONCLUSIONS

Severe VM is often diagnosed after the threshold of viability. Termination of pregnancy was requested in about half the cases owing to the risk of long-term neurodisability, and in all cases diagnosed before 24 weeks. In those live born, there was abnormal outcome in all but one.

Fetal brain monitoring: future applications

Future application of fetal brain monitoring is explored by selecting and analysing articles for information on types of brain damage that can be monitored, where in the brain this can be done, how long after the risk exposure, and with what method of investigation. A limited number of--mainly--case histories reported that early (cell death and oedema) and late (gliosis) effects of brain damage can be demonstrated before birth with multiplanar ultrasound and magnetic resonance imaging, and that hypoxic ischaemic injury or infection can induce local or widespread brain injury, occurring as transient or longer-lasting changes in age-related predilection areas for which normal features are known. The antenatal role of risk factors inducing abnormal brain development can be studied longitudinally with ultrasound and magnetic resonance imaging. A multidisciplinary approach will facilitate the introduction of various techniques with adequate know-how of underlying processes, to evaluate the predictive value on neurological outcome and prevent premature introduction into clinical application.

In utero magnetic resonance of non-isolated ventriculomegaly: Does ventricular size or morphology reflect pathology?

AIM

To confirm whether ventricular size or morphology reflects the underlying pathology in foetuses referred with a diagnosis of possible ventriculomegaly (Vm) and central nervous system (CNS) pathology.

METHODS

Retrospective analysis of 40 in utero magnetic resonance (MR) examinations was undertaken. Ventricular size was measured on axial sections by two observers, and morphology was agreed by consensus. Results were analysed according to gestational age at referral, degree of Vm (mild 10-15 mm, moderate/severe >15 mm) and morphology.

RESULTS

Nine cases had no Vm (mean gestational age 23.6 weeks, range 19-33), 17 had mild Vm (mean age 23.9 weeks, range 20-31), and 14 had moderate/severe Vm (mean age 25.9 weeks, range 20-35). All groups had a mix of morphology and pathology. Eighteen suspected cases of spina bifida were referred and 17 confirmed (mean age 22.6 weeks, range 19-30) using MR. The morphology was mixed, five cases (27.8%) had an angular appearance (this morphology was only seen in cases with spina bifida). Fourteen cases (77.8%) had Vm (eight mild, six severe). Of the thirteen cases of agenesis of the corpus callosum (ACC) suspected on ultrasound, seven were confirmed using MR (mean age 26.5 weeks, range 20-35). Of those seven cases with ACC confirmed on MR, and three additional cases only detected by in utero MR, five had colpocephaly, seven had Vm (four mild, three severe).

CONCLUSION

Severity of Vm did not reflect the type, or presence, of underlying pathology. Morphology appears an indicator of pathology. Angular ventricles should initiate a search for spinal defects. Colpocephaly may indicate ACC.

La malformation de Dandy-Walker

The aim of this review is to summarize our knowledge about Dandy-Walker malformation (DWM) and introduce recent notions about its prognosis. DWM is a malformation associating hypoplasia of the vermis, pseudocystic fourth ventricle, upward displacement of the tentorium, torcular and lateral sinuses and anterio-posterior enlargement of the posterior fossa. It is frequently associated with genetic anomalies, brain malformations (anomalies of gyration, grey matter heterotopias, meningoceles, corpus callosum agenesis...) or systemic malformations (heart, orthopedic, intestinal, urogenital and facial anomalies). It is also part of many syndromes. Its rarity, the difficulty of its diagnosis, the fact that the malformation is mainly known through hospitalized patients, mainly from neurosurgical departments, have made its definition variable and prevents us from having an accurate knowledge of its natural history and prognosis. Hydrocephalus, so frequent in neurosurgical series that some have included it in the definition, is actually rare as has been seen in prenatal series. Treatment, when necessary, is still controversial, the main options remaining cyst fenestration, ventriculo- and/or cystoperitoneal shunts and more recently endoscopic third ventriculostomy. The prognosis, commonly said to be unpredictable, is actually foreseeable after scrutinous observation of the brain anatomy, and mainly of the vermis. A cerebellar vermis with three groups of lobes and two main fissures, as identified on MRI T2 sagittal views, not only has the greatest chance to not be associated with other malformation but also to have a favorable neurocognitive outcome. On the contrary, a deeply dysgenetic vermis with only two or one recognizable lobes is not only constantly associated with other brain malformation but also with poor prognosis. This is a recent advance that may be important for those involved in prenatal counselling.

Third-trimester fetal MRI in isolated 10- to 12-mm ventriculomegaly: is it worth it?

OBJECTIVE

The justification for magnetic resonance imaging (MRI) in isolated mild ventriculomegaly remains controversial. This study was undertaken to evaluate the contribution of third-trimester MRI in isolated 10- to 12-mm fetal ventriculomegaly.

DESIGN

Observational prospective cohort study.

SETTING

Universitary prenatal reference centre.

POPULATION

From February 2000 to May 2005, we prospectively collected data concerning fetuses referred to us for cerebral MRI following detection of ventriculomegaly by ultrasound scan (n= 310).

METHODS

Among these, we identified and analysed those cases in which ventriculomegaly was isolated and did not exceed 12 mm in ultrasound examinations prior to MRI scan (n= 185).

MAIN OUTCOME MEASURE

Cases in which MRI provided additional information that was likely to have an impact on prenatal management were detailed.

RESULTS

During the study period, 310 MRI were performed because of fetal ventriculomegaly. Hundred and eighty-five were suspected to be isolated 10- to 12-mm ventriculomegalies in ultrasound scan and formed our database. MRI confirmed the 10- to 12-mm isolated fetal ventriculomegaly in 106 cases (57.3%) and found other abnormalities in 5 (4.7%) of these 106 cases. MRI found ventricular measurement to be less than 10 mm in 43 cases (23.3%) and more than 12 mm in 36 cases (19.4%). Among these 36 fetuses with ventricle size more than 12 mm, 6 (16.7%) had other abnormalities, whereas MRI did not find other abnormalities in the 43 cases with ventricle size below 10 mm.

CONCLUSION

Before advantages of MRI to ultrasound examination can be demonstrated, it seems reasonable that MRI should remain an investigational tool, restricted to selected clinical situations in which the results are expected to modify case management. Where ultrasound scan suspects isolated ventriculomegaly of 10 to 12 mm, our data suggest that when the finding is confirmed with MRI this could be expected in around 5% of cases. Therefore, the policy of routine MRI in such cases should depend on prenatal centres' priorities.

Fetal central nervous system MR imaging

MR imaging of the fetal brain is rapidly being embraced in clinical practice. Fetal MR imaging is proving to be a powerful modality with which to evaluate the fetal brain and is a valuable complement to prenatal ultrasound. Structural abnormalities, such as cerebral malformations and destructive lesions, can be sonographically occult on prenatal ultrasound yet detectable by fetal MR imaging. Moreover, fetal MR imaging offers the promise of contributing to our understanding of normal as well as abnormal brain development with continued advances in MR imaging techniques, such as diffusion-weighted and parallel imaging.

False positives in the prenatal ultrasound screening of fetal structural anomalies

OBJECTIVE

To describe the false-positive diagnoses of prenatal ultrasound screening of fetal structural anomalies.

METHODS

Pregnancies with fetal structural anomalies either detected prenatally in our center or referred to us, were registered, evaluated, and followed-up prospectively by a multidisciplinary Congenital Defects Committee. After postnatal follow-up was completed, cases were assigned as true positives, false positives or false negatives and categorized by anatomical systems. Pregnancies referred with a nonconfirmed suspicion of anomaly were not included. The false-positive diagnoses were analyzed.

RESULTS

From 1994 to 2004, 903 new registry entries of fetuses structurally abnormal at ultrasound with a complete follow-up were included in the Committee database. There were 76 false positives, accounting for 9.3% of all the prenatally established diagnoses. The urinary tract anomalies were the most frequent false-positive diagnoses found (n = 25; accounting for 8.7% of the urinary tract defects), but the genital anomalies showed the higher rate of no confirmation (n = 5; 15.2%). The specific anomalies most commonly not confirmed were renal pyelectasis (n = 9), cerebral ventriculomegaly (n = 9), abdominal cysts (n = 7) and short limbs (n = 7).

CONCLUSION

Several prenatally diagnosed anomalies would benefit from prudent counseling, because they may be normal variants or transient findings.

Ultrasound Imaging of Fetal Brain Abnormalities

Prenatal ultrasound evaluation of the fetal brain requires documentation of specific structures according to guidelines set by the American College of Radiology and the American Institute of Ultrasound in Medicine. Among these required structures are: cerebellum, cisterna magna, lateral cerebral ventricles, choroid plexus, midline falx, and cavum septum pellucidum. All these structures can be visualized in three crucial planes of imaging that include cisterna magna/cerebellum, cavum septum pellucidum, and ventricular atria. A systematic approach can be achieved by instituting a protocol that includes these three basic levels of imaging of the fetal head. These anatomical levels should be incorporated in daily routine for complete obstetric ultrasound evaluation.