Prenatal Factors Associated with Postnatal Brain Injury in Infants with Congenital Diaphragmatic Hernia

Brain development is altered in rabbit fetuses with congenital diaphragmatic hernia

INTRODUCTION

Children with congenital diaphragmatic hernia (CDH) are at risk for neurodevelopmental delay. Some changes are already present prenatally. Herein, we further examined how the brain develops in fetal rabbits with surgically created DH.

METHODS

Two fetuses underwent surgical DH creation on day 23 (term = d31). DH pups and littermate controls were harvested at term. Ten DH pups and 11 controls underwent transcardial perfusion for brain fixation and measurement of brain volume, brain folding, neuron and synaptic density, pre-oligodendrocyte count, proliferation, and vascularization. Twelve other DH and 11 controls had echocardiographic assessment of cardiac output and aortic and cerebral blood flow, magnetic resonance imaging (9.4 T) for cerebral volumetry, and molecular assessment of vascularization markers.

RESULTS

DH pups had lower lung-to-body weight ratio (1.3 ± 0.3 vs. 2.4 ± 0.3%; p < 0.0001) and lower heart-to-body weight ratio (0.007 ± 0.001 vs. 0.009 ± 0.001; p = 0.0006) but comparable body weight and brain-to-body weight ratio. DH pups had a lower left ventricular ejection fraction, aortic and cerebral blood flow (39 ± 8 vs. 54 ± 15 mm/beat; p = 0.03) as compared to controls but similar left cardiac ventricular morphology. Fetal DH-brains were similar in volume but the cerebellum was less folded (perimeter/surface area: 25.5 ± 1.5 vs. 26.8 ± 1.2; p = 0.049). Furthermore, DH brains had a thinner cortex (143 ± 9 vs. 156 ± 13 μm; p = 0.02). Neuron densities in the white matter were higher in DH fetuses (124 ± 18 vs. 104 ± 14; p = 0.01) with comparable proliferation rates. Pre-oligodendrocyte count was lower, coinciding with the lower endothelial cell count.

CONCLUSION

Rabbits with DH had altered brain development compared to controls prenatally, indicating that brain development is already altered prenatally in CDH.

Longitudinal MRI Evaluation of Brain Development in Fetuses with Congenital Diaphragmatic Hernia around the Time of Fetal Endotracheal Occlusion

BACKGROUND AND PURPOSE

Congenital diaphragmatic hernia is associated with high mortality and morbidity, including evidence suggesting neurodevelopmental comorbidities after birth. The aim of this study was to document longitudinal changes in brain biometry and the cortical folding pattern in fetuses with congenital diaphragmatic hernia compared with healthy fetuses.

MATERIALS AND METHODS

This is a retrospective cohort study including fetuses with isolated congenital diaphragmatic hernia between January 2007 and May 2019, with at least 2 MR imaging examinations. For controls, we used images from fetuses who underwent MR imaging for an unrelated condition that did not compromise fetal brain development and fetuses from healthy pregnant women. Biometric measurements and 3D segmentations of brain structures were used as well as qualitative and quantitative grading of the supratentorial brain. Brain development was correlated with disease-severity markers.

RESULTS

Forty-two fetuses were included, with a mean gestational age at first MR imaging of 28.0 (SD, 2.1) weeks and 33.2 (SD, 1.3) weeks at the second imaging. The mean gestational age in controls was 30.7 (SD, 4.2) weeks. At 28 weeks, fetuses with congenital diaphragmatic hernia had abnormal qualitative and quantitative maturation, more extra-axial fluid, and larger total skull volume. By 33 weeks, qualitative grading scores were still abnormal, but quantitative scoring was in the normal range. In contrast, the extra-axial fluid volume remained abnormal with increased ventricular volume. Normal brain parenchymal volumes were found.

CONCLUSIONS

Brain development in fetuses with congenital diaphragmatic hernia around 28 weeks appears to be delayed. This feature is less prominent at 33 weeks. At this stage, there was also an increase in ventricular and extra-axial space volume.

The fetal lamb model of congenital diaphragmatic hernia shows altered cerebral perfusion using contrast enhanced ultrasound

BACKGROUND

Neurodevelopmental impairment is common in survivors of congenital diaphragmatic hernia (CDH). Altered cerebral perfusion in utero may contribute to abnormal brain development in CDH patients.

METHODS

5 fetal lambs with surgical left-CDH and 5 controls underwent transuterine cranial Doppler and contrast enhanced ultrasound (CEUS). Global and regional perfusion metrics were obtained. Biometric and perfusion data were compared between groups via nonparametric Mann Whitney U test and Spearman's rank order correlation.

RESULTS

No significant differences in cerebral Doppler measurements were identified between groups. By CEUS, CDH animals demonstrated significantly decreased global brain perfusion and increased transit time. With focal regions-of-interest (ROIs), there was a tendency towards decreased perfusion in the central/thalamic region in CDH but not in the peripheral brain parenchyma. Transit time was significantly increased in both ROIs in CDH, whereas flux rate was decreased in the central/thalamic region but not the peripheral brain parenchyma. Biometric CDH severity was correlated to perfusion deficit. There was no difference in cardiomyocyte histology.

CONCLUSION

The fetal lamb model of CDH shows altered cerebral perfusion as measured by CEUS, correlating to disease severity. This suggests a physiological abnormality in fetal cerebrovascular perfusion that may contribute to abnormal brain development and neurodevelopmental impairment in survivors.

Normal Growth, Sexual Dimorphism, and Lateral Asymmetries at Fetal Brain MRI

Background Tools in image reconstruction, motion correction, and segmentation have enabled the accurate volumetric characterization of fetal brain growth at MRI. Purpose To evaluate the volumetric growth of intracranial structures in healthy fetuses, accounting for gestational age (GA), sex, and laterality with use of a spatiotemporal MRI atlas of fetal brain development. Materials and Methods T2-weighted 3.0-T half-Fourier acquired single-shot turbo spin-echo sequence MRI was performed in healthy fetuses from prospectively recruited pregnant volunteers from March 2013 to May 2019. A previously validated section-to-volume reconstruction algorithm was used to generate intensity-normalized superresolution three-dimensional volumes that were registered to a fetal brain MRI atlas with 28 anatomic regions of interest. Atlas-based segmentation was performed and manually refined. Labels included the bilateral hippocampus, amygdala, caudate nucleus, lentiform nucleus, thalamus, lateral ventricle, cerebellum, cortical plate, hemispheric white matter, internal capsule, ganglionic eminence, ventricular zone, corpus callosum, brainstem, hippocampal commissure, and extra-axial cerebrospinal fluid. For fetuses younger than 31 weeks of GA, the subplate and intermediate zones were delineated. A linear regression analysis was used to determine weekly age-related change adjusted for sex and laterality. Results The final analytic sample consisted of 122 MRI scans in 98 fetuses (mean GA, 29 weeks ± 5 [range, 20-38 weeks]). All structures had significant volume growth with increasing GA (P < .001). Weekly age-related change for individual structures in the brain parenchyma ranged from 2.0% (95% CI: 0.9, 3.1; P < .001) in the hippocampal commissure to 19.4% (95% CI: 18.7, 20.1; P < .001) in the cerebellum. The largest sex-related differences were 22.1% higher volume in male fetuses for the lateral ventricles (95% CI: 10.9, 34.4; P < .001). There was rightward volumetric asymmetry of 15.6% for the hippocampus (95% CI: 14.2, 17.2; P < .001) and leftward volumetric asymmetry of 8.1% for the lateral ventricles (95% CI: 3.7, 12.2; P < .001). Conclusion With use of a spatiotemporal MRI atlas, volumetric growth of the fetal brain showed complex trajectories dependent on structure, gestational age, sex, and laterality. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Rollins in this issue.

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

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

Morphometric Analysis of Brain in Newborn with Congenital Diaphragmatic Hernia

Congenital diaphragmatic hernia (CDH) is a severe pediatric disorder with herniation of abdominal viscera into the thoracic cavity. Since neurodevelopmental impairment constitutes a common outcome, we performed morphometric magnetic resonance imaging (MRI) analysis on CDH infants to investigate cortical parameters such as cortical thickness (CT) and local gyrification index (LGI). By assessing CT and LGI distributions and their correlations with variables which might have an impact on oxygen delivery (total lung volume, TLV), we aimed to detect how altered perfusion affects cortical development in CDH. A group of CDH patients received both prenatal (i.e., fetal stage) and postnatal MRI. From postnatal high-resolution T2-weighted images, mean CT and LGI distributions of 16 CDH were computed and statistically compared to those of 13 controls. Moreover, TLV measures obtained from fetal MRI were further correlated to LGI. Compared to controls, CDH infants exhibited areas of hypogiria within bilateral fronto-temporo-parietal labels, while no differences were found for CT. LGI significantly correlated with TLV within bilateral temporal lobes and left frontal lobe, involving language- and auditory-related brain areas. Although the causes of neurodevelopmental impairment in CDH are still unclear, our results may suggest their link with altered cortical maturation and possible impaired oxygen perfusion.

Neurodevelopmental outcomes in children with isolated congenital diaphragmatic hernia: A systematic review and meta-analysis

BACKGROUND

Congenital diaphragmatic hernia (CDH) reportedly has neurologic consequences in childhood however little is known about the impact in isolated CDH.

AIMS

Herein we aimed to describe the risk of neurodevelopmental complications in children born with isolated CDH.

MATERIALS & METHODS

We systematically reviewed literature for reports on the neurological outcome of infants born with isolated CDH. The primary outcome was neurodevelopmental delay. Secondary outcomes included, motor skills, intelligence, vision, hearing, language and behavior abnormalities.

RESULTS

Thirteen out of 87 (15%) studies reported on isolated CDH, including 2624 out of 24,146 children. Neurodevelopmental delay was investigated in four studies and found to be present in 16% (3-34%) of children. This was mainly attributed to motor problems in 13% (2-30%), whereas cognitive dysfunction only in 5% (0-20%) and hearing in 3% (1-7%). One study assessed the effect of fetal surgery. When both isolated and non-isolated children were included, these numbers were higher.

DISCUSSION

This systematic review demonstrates that only a minority of studies focused on isolated CDH, with neurodevelopmental delay present in 16% of children born with CDH.

CONCLUSION

To accurately counsel patients, more research should focus on isolated CDH cases and examine children that underwent fetal surgery.

Neurodevelopmental impairment in children with congenital diaphragmatic hernia: Not an uncommon complication for survivors

PURPOSE

To evaluate neurodevelopmental impairment (NDI) in children born with congenital diaphragmatic hernia (CDH).

METHODS

Using a defined search strategy, a systematic review was conducted to define the incidence and types of NDI, to report abnormal neuroimaging findings and to evaluate possible NDI predictors. A meta-analysis was performed on comparative studies reporting risk factors for NDI, using RevMan 5.3.

RESULTS

Of 3541 CDH children (33 studies), 829 (23%) had NDI, with a higher incidence in CDH survivors who received ECMO treatment (49%) vs. those who had no ECMO (22%; p<0.00001). NDI included neuromuscular hypotonia (42%), hearing (13%) and visual (8%) impairment, neurobehavioral issues (20%), and learning difficulties (31%). Of 288 survivors that had postnatal neuroimaging, 49% had abnormal findings. The main risk factors for NDI were severe pulmonary hypoplasia, large defect size, ECMO use.

CONCLUSIONS

NDI is a relevant problem for CDH survivors, affecting 1 in 4. The spectrum of NDI covers all developmental domains and ranges from motor and sensory (hearing, visual) deficits to cognitive, language, and behavioral impairment. Further studies should be designed to better understand the pathophysiology of NDI in CDH children and to longitudinally monitor infants born with CDH to correct risk factors that can be modifiable.

LEVEL OF EVIDENCE

Level III.

Fetal brain morphometry on prenatal magnetic resonance imaging in congenital diaphragmatic hernia

BACKGROUND

Many infants with congenital diaphragmatic hernia (CDH) show brain abnormality on postnatal brain MRI related to severity of CDH, degree of lung hypoplasia, intrathoracic liver, right diaphragmatic hernia and large diaphragmatic defect. It is not known whether these factors affect brain growth in utero in CDH.

OBJECTIVE

To assess prenatal brain morphometry and abnormalities on fetal MR in congenital diaphragmatic hernia.

MATERIALS AND METHODS

We retrospectively reviewed 109 fetal MRIs in 63 fetuses with CDH from 2009 to 2014 (27 died before discharge, 36 survived to discharge). We compared brain injury and gestational-age-corrected z-scores of brain measurements between survivors and non-survivors. We assessed correlations between brain abnormalities and CDH severity.

RESULTS

Enlarged extraaxial space was the most common abnormality, frequently seen on fetal MRI at >28 weeks of gestation, similar in survivors versus non-survivors. Anteroposterior cerebellar vermis dimension at >28 weeks of gestation was smaller in non-survivors compared to survivors (P=.02) and positively correlated with observed/expected total fetal lung volume (P=.01). Transverse cerebellar diameter at >28 weeks of gestation was also positively correlated with observed/expected total fetal lung volume (P=.04). We did not identify maturational delay, abnormal parenchymal signal or intracranial hemorrhage on fetal MRI.

CONCLUSION

Enlarged extraaxial spaces in the third trimester was the most common abnormality on fetal MRI in congenital diaphragmatic hernia. Cerebellar dimensions on fetal MRI are associated with CDH severity. There was no major brain parenchymal injury on fetal MRI, even in the third trimester, in CDH survivors and non-survivors.