MRI for neurodevelopmental prognostication in the high-risk term infant

Quantification of Diffusion Magnetic Resonance Imaging for Prognostic Prediction of Neonatal Hypoxic-Ischemic Encephalopathy

Neonatal hypoxic-ischemic encephalopathy (HIE) is the leading cause of acquired neonatal brain injury with the risk of developing serious neurological sequelae and death. An accurate and robust prediction of short- and long-term outcomes may provide clinicians and families with fundamental evidence for their decision-making, the design of treatment strategies, and the discussion of developmental intervention plans after discharge. Diffusion tensor imaging (DTI) is one of the most powerful neuroimaging tools with which to predict the prognosis of neonatal HIE by providing microscopic features that cannot be assessed by conventional magnetic resonance imaging (MRI). DTI provides various scalar measures that represent the properties of the tissue, such as fractional anisotropy (FA) and mean diffusivity (MD). Since the characteristics of the diffusion of water molecules represented by these measures are affected by the microscopic cellular and extracellular environment, such as the orientation of structural components and cell density, they are often used to study the normal developmental trajectory of the brain and as indicators of various tissue damage, including HIE-related pathologies, such as cytotoxic edema, vascular edema, inflammation, cell death, and Wallerian degeneration. Previous studies have demonstrated widespread alteration in DTI measurements in severe cases of HIE and more localized changes in neonates with mild-to-moderate HIE. In an attempt to establish cutoff values to predict the occurrence of neurological sequelae, MD and FA measurements in the corpus callosum, thalamus, basal ganglia, corticospinal tract, and frontal white matter have proven to have an excellent ability to predict severe neurological outcomes. In addition, a recent study has suggested that a data-driven, unbiased approach using machine learning techniques on features obtained from whole-brain image quantification may accurately predict the prognosis of HIE, including for mild-to-moderate cases. Further efforts are needed to overcome current challenges, such as MRI infrastructure, diffusion modeling methods, and data harmonization for clinical application. In addition, external validation of predictive models is essential for clinical application of DTI to prognostication.

Development of a composite diffusion tensor imaging score correlating with short-term neurological status in neonatal hypoxic-ischemic encephalopathy

Hypoxic-ischemic encephalopathy (HIE) is the most common cause of neonatal acquired brain injury. Although conventional MRI may predict neurodevelopmental outcomes, accurate prognostication remains difficult. As diffusion tensor imaging (DTI) may provide an additional diagnostic and prognostic value over conventional MRI, we aimed to develop a composite DTI (cDTI) score to relate to short-term neurological function. Sixty prospective neonates treated with therapeutic hypothermia (TH) for HIE were evaluated with DTI, with a voxel size of 1 × 1 × 2 mm. Fractional anisotropy (FA) and mean diffusivity (MD) from 100 neuroanatomical regions (FA/MD *100 = 200 DTI parameters in total) were quantified using an atlas-based image parcellation technique. A least absolute shrinkage and selection operator (LASSO) regression was applied to the DTI parameters to generate the cDTI score. Time to full oral nutrition [short-term oral feeding (STO) score] was used as a measure of short-term neurological function and was correlated with extracted DTI features. Seventeen DTI parameters were selected with LASSO and built into the final unbiased regression model. The selected factors included FA or MD values of the limbic structures, the corticospinal tract, and the frontotemporal cortices. While the cDTI score strongly correlated with the STO score (rho = 0.83, p = 2.8 × 10-16), it only weakly correlated with the Sarnat score (rho = 0.27, p = 0.035) and moderately with the NICHD-NRN neuroimaging score (rho = 0.43, p = 6.6 × 10-04). In contrast to the cDTI score, the NICHD-NRN score only moderately correlated with the STO score (rho = 0.37, p = 0.0037). Using a mixed-model analysis, interleukin-10 at admission to the NICU (p = 1.5 × 10-13) and tau protein at the end of TH/rewarming (p = 0.036) and after rewarming (p = 0.0015) were significantly associated with higher cDTI scores, suggesting that high cDTI scores were related to the intensity of the early inflammatory response and the severity of neuronal impairment after TH. In conclusion, a data-driven unbiased approach was applied to identify anatomical structures associated with some aspects of neurological function of HIE neonates after cooling and to build a cDTI score, which was correlated with the severity of short-term neurological functions.

Methods for Monitoring Risk of Hypoxic Damage in Fetal and Neonatal Brains: A Review

Fetal, perinatal, and neonatal asphyxia are vital health issues for the most vulnerable groups in human beings, including fetuses, newborns, and infants. Severe reduction in oxygen and blood supply to the fetal brain can cause hypoxic-ischemic encephalopathy (HIE), leading to long-term neurological disorders, including mental impairment and cerebral palsy. Such neurological disorders are major healthcare concerns. Therefore, there has been a continuous effort to develop clinically useful diagnostic tools for accurately and quantitatively measuring and monitoring blood and oxygen supply to the fetal and neonatal brain to avoid severe consequences of asphyxia HIE and neonatal encephalopathy. Major diagnostic technologies used for this purpose include fetal heart rate monitoring, fetus scalp blood sampling, ultrasound imaging, magnetic resonance imaging, X-ray computed tomography, and nuclear medicine. In addition, given the limitations and shortcomings of traditional diagnostic methods, emerging technologies such as near-infrared spectroscopy and photoacoustic imaging have also been introduced as stand-alone or complementary solutions to address this critical gap in fetal and neonatal care. This review provides a thorough overview of the traditional and emerging technologies for monitoring fetal and neonatal brain oxygenation status and describes their clinical utility, performance, advantages, and disadvantages.

Brain MRI Radiomics Analysis of School-Aged Children with Tetralogy of Fallot

Introduction

Radiomics could be potential imaging biomarkers by capturing and analyzing the features. Children and adolescents with CHD have worse neurodevelopmental and functional outcomes compared with their peers. Early diagnosis and intervention are the necessity to improve neurological outcomes in CHD patients.

Methods

School-aged TOF patients and their healthy peers were recruited for MRI and neurodevelopmental assessment. LASSO regression was used for dimension reduction. ROC curve graph showed the performance of the model.

Results

Six related features were finally selected for modeling. The final model AUC was 0.750. The radiomics features can be potential significant predictors for neurodevelopmental diagnoses.

Conclusion

The radiomics on the conventional MRI can help predict the neurodevelopment of school-aged children and provide parents with rehabilitation advice as early as possible.

Amplitude of low-frequency fluctuation may be an early predictor of delayed motor development due to neonatal hyperbilirubinemia: a fMRI study

BACKGROUND

Acute bilirubin encephalopathy or kernicterus is the worst consequence of brain damage caused by the elevation of total unbound serum bilirubin (TSB) in neonates. The present study aimed to visualize the characteristic brain regions of neonates with hyperbilirubinemia (HB) using functional magnetic resonance imaging (fMRI) and to measure the amplitude of low-frequency fluctuation (ALFF) values.

METHODS

This was a prospective cohort study, which included newborns with HB who were hospitalized at the Children's Hospital of Fudan University. The control group included neonates admitted with neonatal simple wet lung or pneumonia without neurological disease or brain injury. Newborns were divided into a severe hyperbilirubinemia group (SHB), moderate HB group, and control group based on TSB levels. The newborns completed routine MRI combined with fMRI scans and brainstem auditory evoked potentials (BAEPs) during their hospitalization.

RESULTS

A total of 251 newborns were included in this study. There were 45 patients in the SHB group, 65 in the HB group, and 141 in the control group. The average ALFF value in the basal ganglia region in the SHB group was the highest, which was greater than that in the HB and control groups (P<0.001). The ALFF increased with an increase in TSB concentration. Based on the results of the Bayley Scales of infant development assessment, we further found that the most significant difference in ALFF remained in the basal ganglia region between newborns with motor development scores above 70 (including 70) and below 70. Correlation analysis revealed a strong negative correlation between motor development scores and ALFF (r=-0.691, P<0.001). When ALFF alone was used to predict motor development, the sensitivity was 89%. When ALFF was combined with TSB and BEAP results, the area under the ROC curve was the largest (AUC =0.85). The sensitivity and specificity of the model were 67.86% and 90.77%, respectively.

CONCLUSIONS

The ALFF value may be able to serve as an early imaging biomarker and has a greater sensitivity than TSB or BAEP results in predicting long-term motor development (18 m) in HB.

Prenatal or Perinatal Injury? Diagnosing the Cortically Blind Infant

PURPOSE

To document the association of prenatal brain disruption with secondary perinatal distress in children diagnosed as having cortical visual impairment (CVI).

DESIGN

Retrospective case series.

METHODS

Eight children with severe CVI and clinical history of perinatal events were included. Case histories and neuroimaging studies were reviewed. The main outcome measures were perinatal history, visual and neurologic findings, and magnetic resonance (MR) imaging.

RESULTS

In our patient cohort, MR imaging showed signs of cortical dysgenesis leading to congenital brain malformations such as polymicrogyria consistent with a prenatal timing of CNS injury. Although subcortical white matter changes were common, signs of watershed injury to the visual cortex were absent, suggesting that the visual loss was attributable to a prenatal etiology with secondary birth complications.

CONCLUSION

Some children with CVI and a history of perinatal distress have prenatal dysgenesis of the developing brain. Therefore, a clinical history of perinatal hypoxia-ischemia is nonspecific and merits neuroimaging to identify antecedent brain malformations and timing of injury, which can influence patient diagnosis and management.

Safety and Feasibility of Transcranial Magnetic Stimulation as an Exploratory Assessment of Corticospinal Connectivity in Infants After Perinatal Brain Injury: An Observational Study

BACKGROUND

Perinatal brain injuries often impact the corticospinal system, leading to motor impairment and cerebral palsy. Although transcranial magnetic stimulation (TMS) has been widely used to study corticospinal connectivity in adults and older children, similar studies of young infants are limited.

OBJECTIVES

The objective was to establish the safety and feasibility of advanced TMS assessments of the corticospinal connectivity of young infants with perinatal brain injury.

DESIGN

This was a pilot, cross-sectional study of 3- to 12-month-old (corrected age) infants with perinatal stroke or intracranial hemorrhage.

METHODS

Six participants (2 term, 4 preterm) were assessed with stereotactic neuronavigation-guided TMS. Single-pulse TMS was applied to each hemisphere and responses were recorded simultaneously from both upper limbs. During data collection, vital signs and stress responses were measured to assess safety. Developmental motor outcomes were evaluated using the General Movements Assessment and Bayley Scales of Infant and Toddler Development (3rd edition). A clinical diagnosis of cerebral palsy was recorded, if available.

RESULTS

No adverse events occurred during TMS testing. All sessions were well tolerated. Contralateral motor evoked responses were detected in 4 of 6 participants. Both contralateral and ipsilateral responses were observed in 2 of 6 participants.

LIMITATIONS

TMS responses were not obtained in all participants. This could be related to the location of brain injury or developmental stage of the corticospinal system controlling the wrist flexor muscle group from which responses were recorded.

CONCLUSIONS

This study provides a summary of the framework for performing novel TMS assessments in infants with perinatal brain injury. Implementing this approach to measure corticospinal connectivity in hypothesis-driven studies in young infants appears to be justified. Such studies could inform the characterization of corticospinal development and the neural mechanisms driving recovery following early interventions.

Neonatal brain injury and aberrant connectivity

Brain injury sustained during the neonatal period may disrupt development of critical structural and functional connectivity networks leading to subsequent neurodevelopmental impairment in affected children. These networks can be characterized using structural (via diffusion MRI) and functional (via resting state-functional MRI) neuroimaging techniques. Advances in neuroimaging have led to expanded application of these approaches to study term- and prematurely-born infants, providing improved understanding of cerebral development and the deleterious effects of early brain injury. Across both modalities, neuroimaging data are conducive to analyses ranging from characterization of individual white matter tracts and/or resting state networks through advanced 'connectome-style' approaches capable of identifying highly connected network hubs and investigating metrics of network topology such as modularity and small-worldness. We begin this review by summarizing the literature detailing structural and functional connectivity findings in healthy term and preterm infants without brain injury during the postnatal period, including discussion of early connectome development. We then detail common forms of brain injury in term- and prematurely-born infants. In this context, we next review the emerging body of literature detailing studies employing diffusion MRI, resting state-functional MRI and other complementary neuroimaging modalities to characterize structural and functional connectivity development in infants with brain injury. We conclude by reviewing technical challenges associated with neonatal neuroimaging, highlighting those most relevant to studying infants with brain injury and emphasizing the need for further targeted study in this high-risk population.

Etiology and Clinical Features of Full-Term Neonatal Bacterial Meningitis: A Multicenter Retrospective Cohort Study

Objective: Neonatal bacterial meningitis is a severe infectious disease with a high risk of neurodevelopmental sequelae. The causative pathogens may be related to specific clinical features of the disease. Therefore, this study aimed at determining the pathogen-specific and clinical features of bacterial meningitis in full-term neonates. Methods: We enrolled neonates from the Shanghai Neonate Meningitis Cohort (2005-2017), which is a multicenter retrospective cohort that recruits almost all full-term neonates in Shanghai who underwent lumbar puncture. Patient history and clinical examination results were extracted from the computer-documented information systems of four hospitals. The trends of pathogen distribution were analyzed and differences in the clinical manifestations, treatment, and clinical outcomes at discharge were compared according to the causative pathogen. Logistic regression was used to evaluate the pathogen-specific risk of neurological complications. Results: In total, 518 cases of neonatal meningitis, including 189 proven cases, were included. Group B Streptococcus (GBS) and Escherichia coli (E. coli) were the leading pathogens in proven cases of early-onset and late-onset neonatal meningitis, respectively. The proportion of early-onset and late-onset GBS and late-onset E. coli meningitis cases increased gradually. GBS meningitis had the highest risk of neurological complications, whereas the overall incidence of hydrocephalus and brain abscess in E. coli was higher than that in GBS. Conclusions: Rates of neonatal GBS and E. coli meningitis were high in 2005-2017 in Shanghai, and the risk of neurological complications was also high. Therefore, active prevention, rational use of antibiotics, and continuous monitoring of GBS and E. coli in neonates should be initiated in Shanghai.

Structural cerebral abnormalities and neurodevelopmental status in single ventricle congenital heart disease before Fontan procedure

Objectives

Neonates with single ventricle congenital heart disease are at risk for structural cerebral abnormalities. Little is known about the further evolution of cerebral abnormalities until Fontan procedure.

Methods

Between August 2012 and July 2015, we conducted a prospective cross-sectional two centre study using cerebral magnetic resonance imaging (MRI) and neuro-developmental outcome assessed by the Bayley-III. Forty-seven children (31 male) were evaluated at a mean age of 25.9 ± 3.4 months with hypoplastic left heart syndrome (25) or other single ventricle (22).

Results

Cerebral MRI was abnormal in 17 patients (36.2%) including liquor space enlargements (10), small grey (9) and minimal white (5) matter injuries. Eight of 17 individuals had combined lesions. Median (range) cognitive composite score (CCS) (100, 65-120) and motor composite score (MCS) (97, 55-124) were comparable to the reference data, while language composite score (LCS) (97, 68-124) was significantly lower ( P  = 0.040). Liquor space enlargement was associated with poorer performance on all Bayley-III subscores (CCS: P  = 0.02; LCS: P  = 0.002; MCS: P  = 0.013). The number of re-operations [odds ratio (OR) 2.2, 95% confidence interval (CI) 1.1-4.3] ( P  = 0.03) and re-interventions (OR 2.1, 95% CI 1.1-3.8) ( P  = 0.03) was associated with a higher rate of overall MRI abnormalities.

Conclusions

Cerebral MRI abnormalities occur in more than one third of children with single ventricle, while the neuro-developmental status is less severely affected before Fontan procedure. Liquor space enlargement is the predominant MRI finding associated with poorer neuro-developmental status, warranting further studies to determine aetiology and further evolution until school-age.

The neurodevelopmental implications of hypoplastic left heart syndrome in the fetus

As survival after cardiac surgery continues to improve, an increasing number of patients with hypoplastic left heart syndrome are reaching school age and beyond, with growing recognition of the wide range of neurodevelopmental challenges many survivors face. Improvements in fetal detection rates, coupled with advances in fetal ultrasound and MRI imaging, are contributing to a growing body of evidence that abnormal brain architecture is in fact present before birth in hypoplastic left heart syndrome patients, rather than being solely attributable to postnatal factors. We present an overview of the contemporary data on neurodevelopmental outcomes in hypoplastic left heart syndrome, focussing on imaging techniques that are providing greater insight into the nature of disruptions to the fetal circulation, alterations in cerebral blood flow and substrate delivery, disordered brain development, and an increased potential for neurological injury. These susceptibilities are present before any intervention, and are almost certainly substantial contributors to adverse neurodevelopmental outcomes in later childhood. The task now is to determine which subgroups of patients with hypoplastic left heart syndrome are at particular risk of poor neurodevelopmental outcomes and how that risk might be modified. This will allow for more comprehensive counselling for carers, better-informed decision making before birth, and earlier, more tailored provision of neuroprotective strategies and developmental support in the postnatal period.

Optimizing Cerebral Autoregulation May Decrease Neonatal Regional Hypoxic-Ischemic Brain Injury

BACKGROUND

Therapeutic hypothermia provides incomplete neuroprotection for neonatal hypoxic-ischemic encephalopathy (HIE). We examined whether hemodynamic goals that support autoregulation are associated with decreased brain injury and whether these relationships are affected by birth asphyxia or vary by anatomic region.

METHODS

Neonates cooled for HIE received near-infrared spectroscopy autoregulation monitoring to identify the mean arterial blood pressure with optimized autoregulatory function (MAPOPT). Blood pressure deviation from MAPOPT was correlated with brain injury on MRI after adjusting for the effects of arterial carbon dioxide, vasopressors, seizures, and birth asphyxia severity.

RESULTS

Blood pressure deviation from MAPOPT related to neurologic injury in several regions independent of birth asphyxia severity. Greater duration and deviation of blood pressure below MAPOPT were associated with greater injury in the paracentral gyri and white matter. Blood pressure within MAPOPT related to lesser injury in the white matter, putamen and globus pallidus, and brain stem. Finally, blood pressures that exceeded MAPOPT were associated with reduced injury in the paracentral gyri.

CONCLUSIONS

Blood pressure deviation from optimal autoregulatory vasoreactivity was associated with MRI markers of brain injury that, in many regions, were independent of the initial birth asphyxia. Targeting hemodynamic ranges to optimize autoregulation has potential as an adjunctive therapy to hypothermia for HIE.

Prognostic factors of neurological outcomes in late-preterm and term infants with perinatal asphyxia

PURPOSE

This study aimed to identify prognostic factors of neurological outcomes, including developmental delay, cerebral palsy and epilepsy in late-preterm and term infants with perinatal asphyxia.

METHODS

All late-preterm and term infants with perinatal asphyxia or hypoxic-ischemic insults who admitted the neonatal intensive care unit of Inje University Sanggye Paik Hospital between 2006 and 2014 and were followed up for at least 2 years were included in this retrospective study. Abnormal neurological outcomes were defined as cerebral palsy, developmental delay and epilepsy.

RESULTS

Of the 114 infants with perinatal asphyxia, 31 were lost to follow-up. Of the remaining 83 infants, 10 died, 56 had normal outcomes, and 17 had abnormal outcomes: 14 epilepsy (82.4%), 13 cerebral palsy (76.5%), 16 developmental delay (94.1%). Abnormal outcomes were significantly more frequent in infants with later onset seizure, clinical seizure, poor electroencephalography (EEG) background activity, lower Apgar score at 1 and 5 minutes and abnormal brain imaging (P<0.05). Infants with and without epilepsy showed significant differences in EEG background activity, clinical and electrographic seizures on EEG, Apgar score at 5 minutes and brain imaging findings.

CONCLUSION

We should apply with long-term video EEG or amplitude integrated EEG in order to detect and management subtle clinical or electrographic seizures in neonates with perinatal asphyxia. Also, long-term, prospective studies with large number of patients are needed to evaluate more exact prognostic factors in neonates with perinatal asphyxia.