Volumetric Brain MRI Study in Fetuses with Congenital Heart Disease

Fetal MRI of the heart and brain in congenital heart disease

Antenatal assessment of congenital heart disease and associated anomalies by ultrasound has improved perinatal care. Fetal cardiovascular MRI and fetal brain MRI are rapidly evolving for fetal diagnostic testing of congenital heart disease. We give an overview on the use of fetal cardiovascular MRI and fetal brain MRI in congenital heart disease, focusing on the current applications and diagnostic yield of structural and functional imaging during pregnancy. Fetal cardiovascular MRI in congenital heart disease is a promising supplementary imaging method to echocardiography for the diagnosis of antenatal congenital heart disease in weeks 30-40 of pregnancy. Concomitant fetal brain MRI is superior to brain ultrasound to show the complex relationship between fetal haemodynamics in congenital heart disease and brain development.

Altered Cerebral Microstructure in Adults With Atrial Septal Defect and Ventricular Septal Defect Repaired in Childhood

Background

Delayed brain development, brain injury, and neurodevelopmental disabilities are commonly observed in infants operated for complex congenital heart defect. Our previous findings of poorer neurodevelopmental outcomes in individuals operated for simple congenital heart defects calls for further etiological clarification. Hence, we examined the microstructural tissue composition in cerebral cortex and subcortical structures in comparison to healthy controls and whether differences were associated with neurodevelopmental outcomes.

Methods and Results

Adults (n=62) who underwent surgical closure of an atrial septal defect (n=33) or a ventricular septal defect (n=29) in childhood and a group of healthy, matched controls (n=38) were enrolled. Brain diffusional kurtosis imaging and neuropsychological assessment were performed. Cortical and subcortical tissue microstructure were assessed using mean kurtosis tensor and mean diffusivity and compared between groups and tested for associations with neuropsychological outcomes. Alterations in microstructural tissue composition were found in the parietal, temporal, and occipital lobes in the congenital heart defects, with distinct mean kurtosis tensor cluster‐specific changes in the right visual cortex (pericalcarine gyrus, P=0.002; occipital part of fusiform and lingual gyri, P=0.019). Altered microstructural tissue composition in the subcortical structures was uncovered in atrial septal defects but not in ventricular septal defects. Associations were found between altered cerebral microstructure and social recognition and executive function.

Conclusions

Children operated for simple congenital heart defects demonstrated altered microstructural tissue composition in the cerebral cortex and subcortical structures during adulthood when compared with healthy peers. Alterations in cerebral microstructural tissue composition were associated with poorer neuropsychological performance.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03871881.

Chromosomal Microarray Analysis in Fetuses Detected with Isolated Cardiovascular Malformation: A Multicenter Study, Systematic Review of the Literature and Meta-Analysis

Cardiovascular malformations (CVM) represent the most common structural anomalies, occurring in 0.7% of live births. The CVM prenatal suspicion should prompt an accurate investigation with fetal echocardiography and the assessment through genetic counseling and testing. In particular, chromosomal microarray analysis (CMA) allows the identification of copy number variations. We performed a systematic review and meta-analysis of the literature, studying the incremental diagnostic yield of CMA in fetal isolated CVM, scoring yields for each category of heart disease, with the aim of guiding genetic counseling and prenatal management. At the same time, we report 59 fetuses with isolated CVM with normal karyotype who underwent CMA. The incremental CMA diagnostic yield in fetuses with isolated CVM was 5.79% (CI 5.54–6.04), with conotruncal malformations showing the higher detection rate (15.93%). The yields for ventricular septal defects and aberrant right subclavian artery were the lowest (2.64% and 0.66%). Other CVM ranged from 4.42% to 6.67%. In the retrospective cohort, the diagnostic yield was consistent with literature data, with an overall CMA diagnostic yield of 3.38%. CMA in the prenatal setting was confirmed as a valuable tool for investigating the causes of fetal cardiovascular malformations.

Brainstem and cerebellar volumes at magnetic resonance imaging are smaller in fetuses with congenital heart disease

BACKGROUND

Congenital heart disease is associated with an increased risk of smaller brain volumes and structural brain damage, and impaired growth of supratentorial brain structures in utero has been linked to poor neurodevelopmental outcomes. However, little is known on brainstem and cerebellar volumes in fetuses with congenital heart disease. Moreover, it is not clear whether impaired infratentorial growth, if present, is associated with only certain types of fetal cardiac defects or with supratentorial brain growth, and whether altered biometry is already present before the third trimester.

OBJECTIVE

This study aimed to investigate brainstem and cerebellar volumes in fetuses with congenital heart disease and to compare them to infratentorial brain volumes in fetuses with normal hearts. Secondarily, the study aimed to identify associations between infratentorial brain biometry and the type of cardiac defects, supratentorial brain volumes, and gestational age.

STUDY DESIGN

In this retrospective case-control study, 141 magnetic resonance imaging studies of 135 fetuses with congenital heart disease and 141 magnetic resonance imaging studies of 125 controls with normal hearts at 20 to 37 gestational weeks (median, 25 weeks) were evaluated. All cases and controls had normal birthweight and no evidence of structural brain disease or genetic syndrome. Six types of congenital heart disease were included: tetralogy of Fallot (n=32); double-outlet right ventricle (n=22); transposition of the great arteries (n=27); aortic obstruction (n=24); hypoplastic left heart syndrome (n=22); and hypoplastic right heart syndrome (n=14). First, brainstem and cerebellar volumes of each fetus were segmented and compared between cases and controls. In addition, transverse cerebellar diameters, vermian areas, and supratentorial brain and cerebrospinal fluid volumes were quantified and differences assessed between cases and controls. Volumetric differences were further analyzed according to types of cardiac defects and supratentorial brain volumes. Finally, volume ratios were created for each brain structure ([volume in fetus with congenital heart disease/respective volume in control fetus] × 100) and correlated to gestational age.

RESULTS

Brainstem (cases, 2.1 cm³ vs controls, 2.4 cm³; P<.001) and cerebellar (cases, 3.2 cm³ vs controls, 3.4 cm³; P<.001) volumes were smaller in fetuses with congenital heart disease than in controls, whereas transverse cerebellar diameters (P=.681) and vermian areas (P=.947) did not differ between groups. Brainstem and cerebellar volumes differed between types of cardiac defects. Overall, the volume ratio of cases to controls was 80.8% for the brainstem, 90.5% for the cerebellum, and 90.1% for the supratentorial brain. Fetuses with tetralogy of Fallot and transposition of the great arteries were most severely affected by total brain volume reduction. Gestational age had no effect on volume ratios.

CONCLUSION

The volume of the infratentorial brain, which contains structures considered crucial to brain function, is significantly smaller in fetuses with congenital heart disease than in controls from midgestation onward. These findings suggest that impaired growth of both supra- and infratentorial brain structures in fetuses with congenital heart disease occurs in the second trimester. Further research is needed to elucidate associations between fetal brain volumes and neurodevelopmental outcomes in congenital heart disease.

Altered brain structure in preschool-aged children with tetralogy of Fallot

BACKGROUND

Neurodevelopmental abnormalities are prevalent in children with tetralogy of Fallot. Our aim was to investigate the structural brain alterations of preschool-aged children with tetralogy of Fallot and its correlation with neurodevelopmental outcome.

METHODS

T1-weighted structural images were obtained from 25 children with tetralogy of Fallot who had undergone cardiopulmonary bypass surgery and from 24 normal controls. Cortical morphological indices including gray matter volume, cortical thickness, sulcal depth, gyrification, and cortical surface complexity were compared between the two groups. Neurodevelopmental assessments of the children with tetralogy of Fallot were performed with the Wechsler Preschool and Primary Scale of Intelligence.

RESULTS

Cortical morphological differences between groups were distributed throughout the right caudal middle frontal gyrus, right fusiform gyrus, right lateral occipital gyrus, right precuneus, and left inferior parietal lobule. Among children with tetralogy of Fallot, altered cortical structures were correlated with the visual spatial index, working memory index, and perioperative variables.

CONCLUSION

Our results suggested that abnormal cortical structure in preschool-aged children with tetralogy of Fallot may be the persistent consequence of delayed cortical development in fetuses and cortical morphology can be used as an early potential biomarker to capture regional brain abnormalities that are relevant to neurodevelopmental outcomes.

IMPACT

Altered cortical structures in preschool-aged children with ToF were correlated with both neurodevelopmental outcomes and clinical risk factors. Cortical morphology can be used as an effective tool to evaluate neuroanatomical changes and detect underlying neural mechanisms in ToF patients. Abnormal cortical structure may be the continuous consequence of delayed fetal brain development in children with ToF.

Neuroplacentology in congenital heart disease: placental connections to neurodevelopmental outcomes

Children with congenital heart disease (CHD) are living longer due to effective medical and surgical management. However, the majority have neurodevelopmental delays or disorders. The role of the placenta in fetal brain development is unclear and is the focus of an emerging field known as neuroplacentology. In this review, we summarize neurodevelopmental outcomes in CHD and their brain imaging correlates both in utero and postnatally. We review differences in the structure and function of the placenta in pregnancies complicated by fetal CHD and introduce the concept of a placental inefficiency phenotype that occurs in severe forms of fetal CHD, characterized by a myriad of pathologies. We propose that in CHD placental dysfunction contributes to decreased fetal cerebral oxygen delivery resulting in poor brain growth, brain abnormalities, and impaired neurodevelopment. We conclude the review with key areas for future research in neuroplacentology in the fetal CHD population, including (1) differences in structure and function of the CHD placenta, (2) modifiable and nonmodifiable factors that impact the hemodynamic balance between placental and cerebral circulations, (3) interventions to improve placental function and protect brain development in utero, and (4) the role of genetic and epigenetic influences on the placenta-heart-brain connection. IMPACT: Neuroplacentology seeks to understand placental connections to fetal brain development. In fetuses with CHD, brain growth abnormalities begin in utero. Placental microstructure as well as perfusion and function are abnormal in fetal CHD.

Reference biometry of foetal brain by prenatal MRI and the distribution of measurements in foetuses with ventricular septal defect

OBJECTIVE

To provide the reference biometric measurements of the normal foetal brain by prenatal MRI and describe the distribution of measurements in the foetuses with ventricular septal defect (VSD).

METHODS

This retrospective study analysed the biometric measurements of 218 foetuses between 18 - 37 gestational weeks with normal MRI findings from July 2014 to August 2019, as well as 18 foetuses with VSD. The measurements included fronto-occipital diameter (FOD), biparietal diameter (BPD), and transverse cerebellar diameter (TCD). All the prenatal MRI examinations have been taken on the same 1.5 T MR unit with a standard protocol of the foetal brain. All the linear measurements of the foetal brain were obtained on the T2-weighted imaging. The distribution of measurements in 18 foetuses with VSD was plotted on centile curves.

RESULTS

The reference data were presented in mean, standard deviation, 95% predicted confidence intervals, and the 3rd, 10th, 25th, 50th, 75th, 90th, 97th centiles at each gestational age. The value of TCD in 56% (10/18 cases) foetuses with VSD was lower than the 3rd centile, and the rate for FOD and BPD was 33% (6/18 cases) and 22% (4/18 cases) separately. On the curves, most VSD cases with measurements lower than the 3rd centile were in relatively early gestational stage (≤28 weeks).

CONCLUSIONS

We have presented reference linear biometry of the foetal brain by prenatal MRI from 18 to 37 gestational weeks, which could help us to interpret and monitor the brain development for foetuses with VSD and other congenital heart diseases.Key messages:We have presented reference linear biometry of the foetal brain by prenatal MRI from 18 to 37 gestational weeks in multiple statistical methods: mean and standard deviation; 95% predicted confidence intervals and the 3rd, 10th, 25th, 50th, 75th, 90th, 97th centiles.Our data showed that the involvement of the brain in VSD may be not globally, but regionally, and the cerebellum may be more possible to be involved.We speculated that the earlier the VSD diagnosed the worse the brain involved, which might suggest a poor outcome and necessary follow-up.

Correlation between 2D and 3D Fetal Brain MRI Biometry and Neurodevelopmental Outcomes in Fetuses with Suspected Microcephaly and Macrocephaly

BACKGROUND AND PURPOSE

Definitions of fetal microcephaly and macrocephaly are debatable. A better understanding of their long-term prognoses would help guide parental education and counseling. This study aimed to explore the correlation between 2D and 3D fetal brain MR imaging biometry results and the long-term neurodevelopmental outcomes.

MATERIALS AND METHODS

This analysis is a historical cohort study. Fetal brain biometry was measured on 2D and 3D MR imaging using a volumetric MR imaging semiautomated algorithm. We measured and assessed the following brain structures: the supratentorial brain volume and cerebellar volume and cerebellar volume/supratentorial brain volume ratio, in addition to commonly used 2D brain MR imaging biometric variables, including occipitofrontal diameter, biparietal diameter, and transcerebellar diameter. Microcephaly was defined as ≤ 3rd percentile; and macrocephaly, as ≥ 97th percentile, corresponding to -2 SDs and +2 SDs. The neurodevelopmental outcome of this study cohort was evaluated using the Vineland-II Adaptive Behavior Scales, and the measurements were correlated to the Vineland standard scores.

RESULTS

A total of 70 fetuses were included. No significant correlation was observed between the Vineland scores and either the supratentorial brain volume, cerebellar volume, or supratentorial brain volume/cerebellar volume ratio in 3D or 2D MR imaging measurements, after correction for multiple comparisons. No differences were found among fetuses with macrocephaly, normocephaly, or microcephaly regarding the median Vineland standard scores.

CONCLUSIONS

Provided there is normal brain structure on MR imaging, the developmental milestone achievements in early years are unrelated to 2D and 3D fetal brain MR imaging biometry, in the range of measurements depicted in this study.

Fetal brain issues in congenital heart disease

Following the improvements in the clinical management of patients with congenital heart disease (CHD) and their increased survival, neurodevelopmental outcome has become an emerging priority in pediatric cardiology. Large-scale efforts have been made to protect the brain during the postnatal, surgical, and postoperative period; however, the presence of brain immaturity and injury at birth suggests in utero and peripartum disturbances. Over the past decade, there has been considerable interest and investigations on fetal brain growth in the setting of CHD. Advancements in fetal brain imaging have identified abnormal brain development in fetuses with CHD from the macrostructural (brain volumes and cortical folding) down to the microstructural (biochemistry and water diffusivity) scale, with more severe forms of CHD showing worse disturbances and brain abnormalities starting as early as the first trimester. Anomalies in common genetic developmental pathways and diminished cerebral substrate delivery secondary to altered cardiovascular physiology are the forefront hypotheses, but other factors such as impaired placental function and maternal psychological stress have surfaced as important contributors to fetal brain immaturity in CHD. The characterization and timing of fetal brain disturbances and their associated mechanisms are important steps for determining preventative prenatal interventions, which may provide a stronger foundation for the developing brain during childhood.

MRI studies of brain size and growth in individuals with congenital heart disease

Congenital heart disease (CHD) is the most frequent congenital abnormality. Most infants born with CHD now survive. However, survivors of CHD are at increased risk of neurodevelopmental impairment, which may be due to impaired brain development in the fetal and neonatal period. Magnetic resonance imaging (MRI) provides objective measures of brain volume and growth. Here, we review MRI studies assessing brain volume and growth in individuals with CHD from the fetus to adolescence. Smaller brain volumes compared to healthy controls are evident from around 30 weeks gestation in fetuses with CHD and are accompanied by increased extracerebral cerebrospinal fluid. This impaired brain growth persists after birth and throughout childhood to adolescence. Risk factors for impaired brain growth include reduced cerebral oxygen delivery in utero, longer time to surgery and increased hospital stay. There is increasing evidence that smaller total and regional brain volumes in this group are associated with adverse neurodevelopmental outcome. However, to date, few studies have assessed the association between early measures of cerebral volume and neurodevelopmental outcome in later childhood. Large prospective multicentre studies are required to better characterise the relationship between brain volume and growth, clinical risk factors and subsequent cognitive, motor, and behavioural impairments in this at-risk population.

Prenatal cerebellar growth is altered in congenital diaphragmatic hernia on ultrasound

OBJECTIVE

Children with congenital diaphragmatic hernia (CDH) are at risk for neurodevelopmental delay. Herein we report on prenatal changes in biometry and brain perfusion in fetuses with isolated CDH.

STUDY DESIGN

This retrospective study evaluated fetuses with isolated, left-sided CDH in three European referral centers. Abdominal circumference (AC), femur length (FL), head circumference (HC), transcerebellar diameter (TCD), middle cerebral artery (MCA) Doppler, and ventricular width (VW) were assessed during four gestational periods (<24 weeks, 25-28 weeks, 29-32 weeks, >33 weeks). Z-scores were calculated, and growth curves were created based on longitudinal data.

RESULTS

In 367 fetuses, HC, AC and FL were within normal ranges throughout gestation. The TCD diminished with advancing gestational age to fall below the fifth percentile after 32 weeks. A less pronounced but similar trend was seen in VW. The peak systolic velocity of the MCA was consistently approximately 10% lower than normal. Disease severity was correlated to TCD (p = 0.002) and MCA doppler values (p = 0.002). There were no differences between fetuses treated with FETO and those managed expectantly.

CONCLUSION

Fetuses with isolated left-sided CDH have a small cerebellum and reduced MCA peak systolic velocity. Follow up studies are necessary to determine the impact of these changes on neurodevelopment.

Tractography of the Cerebellar Peduncles in Second- and Third-Trimester Fetuses

BACKGROUND AND PURPOSE

Little is known about microstructural development of cerebellar white matter in vivo. This study aimed to investigate developmental changes of the cerebellar peduncles in second- and third-trimester healthy fetuses using motion-corrected DTI and tractography.

MATERIALS AND METHODS

3T data of 81 healthy fetuses were reviewed. Structural imaging consisted of multiplanar T2-single-shot sequences; DTI consisted of a series of 12-direction diffusion. A robust motion-tracked section-to-volume registration algorithm reconstructed images. ROI-based deterministic tractography was performed using anatomic landmarks described in postnatal tractography. Asymmetry was evaluated qualitatively with a perceived difference of >25% between sides. Linear regression evaluated gestational age as a predictor of tract volume, ADC, and fractional anisotropy.

RESULTS

Twenty-four cases were excluded due to low-quality reconstructions. Fifty-eight fetuses with a median gestational age of 30.6 weeks (interquartile range, 7 weeks) were analyzed. The superior cerebellar peduncle was identified in 39 subjects (69%), and it was symmetric in 15 (38%). The middle cerebellar peduncle was identified in all subjects and appeared symmetric; in 13 subjects (22%), two distinct subcomponents were identified. The inferior cerebellar peduncle was not found in any subject. There was a significant increase in volume for the superior cerebellar peduncle and middle cerebellar peduncle (both, P < .05), an increase in fractional anisotropy (both, P < .001), and a decrease in ADC (both, P < .001) with gestational age. The middle cerebellar peduncle had higher volume (P < .001) and fractional anisotropy (P = .002) and lower ADC (P < .001) than the superior cerebellar peduncle after controlling for gestational age.

CONCLUSIONS

A robust motion-tracked section-to-volume registration algorithm enabled deterministic tractography of the superior cerebellar peduncle and middle cerebellar peduncle in vivo and allowed characterization of developmental changes.

Antenatal and Perioperative Mechanisms of Global Neurological Injury in Congenital Heart Disease

Congenital heart defects (CHD) is one of the most common types of birth defects. Thanks to advances in surgical techniques and intensive care, the majority of children with severe forms of CHD survive into adulthood. However, this increase in survival comes with a cost. CHD survivors have neurological functioning at the bottom of the normal range. A large spectrum of central nervous system dysmaturation leads to the deficits seen in critical CHD. The heart develops early during gestation, and CHD has a profound effect on fetal brain development for the remainder of gestation. Term infants with critical CHD are born with an immature brain, which is highly susceptible to hypoxic-ischemic injuries. Perioperative blood flow disturbances due to the CHD and the use of cardiopulmonary bypass or circulatory arrest during surgery cause additional neurological injuries. Innate patient factors, such as genetic syndromes and preterm birth, and postoperative complications play a larger role in neurological injury than perioperative factors. Strategies to reduce the disability burden in critical CHD survivors are urgently needed.

Normative linear and volumetric biometric measurements of fetal brain development in magnetic resonance imaging

PURPOSE

To provide normative two-dimensional and three-dimensional measurements of brain development in normal fetuses during the second and third trimester by a new semi-automated method.

METHODS

In this retrospective study, we included 98 normal fetuses at our institution between 21 and 38 weeks of gestation. Two-dimensional measurements of the brain were including biparietal diameter, occipitofrontal diameter, head circumference, transverse cerebellar diameter, and atrial diameter. Volumetric parameters were obtained by using ITK-SNAP software, including left and right cerebral hemispheres, lateral ventricle, the cerebellum, and extracerebral cerebrospinal fluid.

RESULTS

All linear and volume measurements were positively correlated with gestational age except for cerebrospinal fluid. Each anatomical region of the fetal brain showed a different relative growth rate. There was some volume asymmetry between the left and right lateral ventricles, and the left side was larger. The inter-observer and intra-observer agreement was excellent for all measures.

CONCLUSION

We established the 5th, 50th, and 95th percentile values of fetal brain volume measurements in magnetic resonance, and this may be helpful to understand the damage of fetal brain development.

Regional Brain Growth Trajectories in Fetuses with Congenital Heart Disease

OBJECTIVE

Congenital heart disease (CHD) is associated with abnormal brain development in utero. We applied innovative fetal magnetic resonance imaging (MRI) techniques to determine whether reduced fetal cerebral substrate delivery impacts the brain globally, or in a region-specific pattern. Our novel design included two control groups, one with and the other without a family history of CHD, to explore the contribution of shared genes and/or fetal environment to brain development.

METHODS

From 2014 to 2018, we enrolled 179 pregnant women into 4 groups: "HLHS/TGA" fetuses with hypoplastic left heart syndrome (HLHS) or transposition of the great arteries (TGA), diagnoses with lowest fetal cerebral substrate delivery; "CHD-other," with other CHD diagnoses; "CHD-related," healthy with a CHD family history; and "optimal control," healthy without a family history. Two MRIs were obtained between 18 and 40 weeks gestation. Random effect regression models assessed group differences in brain volumes and relationships to hemodynamic variables.

RESULTS

HLHS/TGA (n = 24), CHD-other (50), and CHD-related (34) groups each had generally smaller brain volumes than the optimal controls (71). Compared with CHD-related, the HLHS/TGA group had smaller subplate (-13.3% [standard error = 4.3%], p < 0.01) and intermediate (-13.7% [4.3%], p < 0.01) zones, with a similar trend in ventricular zone (-7.1% [1.9%], p = 0.07). These volumetric reductions were associated with lower cerebral substrate delivery.

INTERPRETATION

Fetuses with CHD, especially those with lowest cerebral substrate delivery, show a region-specific pattern of small brain volumes and impaired brain growth before 32 weeks gestation. The brains of fetuses with CHD were more similar to those of CHD-related than optimal controls, suggesting genetic or environmental factors also contribute. ANN NEUROL 2021;89:143-157.

The Congenital Heart Disease Brain: Prenatal Considerations for Perioperative Neurocritical Care

Altered brain development has been highlighted as an important contributor to adverse neurodevelopmental outcomes in children with congenital heart disease. Abnormalities begin prenatally and include micro- and macrostructural disturbances that lead to an altered trajectory of brain growth throughout gestation. Recent progress in fetal imaging has improved understanding of the neurobiological mechanisms and risk factors for impaired fetal brain development. The impact of the prenatal environment on postnatal neurological care has also gained increased focus. This review summarizes current data on the timing and pattern of altered prenatal brain development in congenital heart disease, the potential mechanisms of these abnormalities, and the association with perioperative neurological complications.

Recent advances in our understanding of neurodevelopmental outcomes in congenital heart disease

PURPOSE OF REVIEW

Patients with congenital heart disease (CHD) suffer from a pattern of neurodevelopmental abnormalities including deficits in language and executive function. In this review, we summarize recent studies that examine these outcomes, their risk factors, possible biomarkers, and attempts to develop therapeutic interventions.

RECENT FINDINGS

The latest literature has highlighted the role of genetics in determining neurologic prognosis, as we have increased our understanding of potentially modifiable perioperative risk factors. The role of potentially neurotoxic medical therapies has become more salient. One recent focus has been how neurodevelopment affects quality of life and leads to a high prevalence of mental illness. Neuroimaging advances have provided new insights into the pathogenesis of deficits.

SUMMARY

Although many risk factors in CHD are not modifiable, there is promise for interventions to improve neurodevelopmental outcomes in patients with CHD. Biomarkers are needed to better understand the timing and prognosis of injury and to direct therapy. Research into psychosocial interventions is urgently needed to benefit the many survivors with CHD.

Prenatal to postnatal trajectory of brain growth in complex congenital heart disease

Altered brain development is a common feature of the neurological sequelae of complex congenital heart disease (CHD). These alterations include abnormalities in brain size and growth that begin prenatally and persist postnatally. However, the longitudinal trajectory of changes in brain volume from the prenatal to postnatal environment have not been investigated. We aimed to evaluate the trajectory of brain growth in a cohort of patients with complex CHD (n = 16) and healthy controls (n = 15) to test the hypothesis that patients with complex CHD would have smaller total brain volume (TBV) prenatally, which would become increasingly prominent by three months of age. Participants underwent fetal magnetic resonance imaging (MRI) at a mean of 32 weeks gestation, a preoperative/neonatal MRI shortly after birth, a postoperative MRI (CHD only), and a 3-month MRI to evaluate the trajectory of brain growth. Three-dimensional volumetric analysis was applied to the MRI data to measure TBV, as well as tissue-specific volumes of the cortical gray matter (CGM), white matter (WM), subcortical (deep nuclear) gray matter (SCGM), cerebellum, and cerebrospinal fluid (CSF). A random coefficients model was used to investigate longitudinal changes in TBV and demonstrated an altered trajectory of brain growth in the CHD population. The estimated slope for TBV from fetal to 3-month MRI was 11.5 cm³ per week for CHD infants compared to 16.7 cm³ per week for controls (p = 0.0002). Brain growth followed a similar trajectory for the CGM (p < 0.0001), SCGM (p = 0.002), and cerebellum (p = 0.005). There was no difference in growth of the WM (p = 0.30) or CSF (p = 0.085). Brain injury was associated with reduced TBV at 3-month MRI (p = 0.02). After removing infants with brain injury from the model, an altered trajectory of brain growth persisted in CHD infants (p = 0.006). These findings extend the existing literature by demonstrating longitudinal impairments in brain development in the CHD population and emphasize the global nature of disrupted brain growth from the prenatal environment through early infancy.