MR patterns of hypoxic-ischemic brain damage after prenatal, perinatal or postnatal asphyxia

Anatomo-functional changes in neural substrates of cognitive memory in developmental amnesia: Insights from automated and manual Magnetic Resonance Imaging examinations

Despite bilateral hippocampal damage dating to the perinatal or early childhood period and severely impaired episodic memory, patients with developmental amnesia continue to exhibit well-developed semantic memory across the developmental trajectory. Detailed information on the extent and focality of brain damage in these patients is needed to hypothesize about the neural substrate that supports their remarkable capacity for encoding and retrieval of semantic memory. In particular, we need to assess whether the residual hippocampal tissue is involved in this preservation, or whether the surrounding cortical areas reorganize to rescue aspects of these critical cognitive memory processes after early injury. We used voxel-based morphometry (VBM) analysis, automatic (FreeSurfer) and manual segmentation to characterize structural changes in the brain of an exceptionally large cohort of 23 patients with developmental amnesia in comparison with 32 control subjects. Both the VBM and the FreeSurfer analyses revealed severe structural alterations in the hippocampus and thalamus of patients with developmental amnesia. Milder damage was found in the amygdala, caudate, and parahippocampal gyrus. Manual segmentation demonstrated differences in the degree of atrophy of the hippocampal subregions in patients. The level of atrophy in CA-DG subregions and subicular complex was more than 40%, while the atrophy of the uncus was moderate (-24%). Anatomo-functional correlations were observed between the volumes of residual hippocampal subregions in patients and selective aspects of their cognitive performance, viz, intelligence, working memory, and verbal and visuospatial recall. Our findings suggest that in patients with developmental amnesia, cognitive processing is compromised as a function of the extent of atrophy in hippocampal subregions. More severe hippocampal damage may be more likely to promote structural and/or functional reorganization in areas connected to the hippocampus. In this hypothesis, different levels of hippocampal function may be rescued following this variable reorganization. Our findings document not only the extent, but also the limits of circuit reorganization occurring in the young brain after early bilateral hippocampal damage.

Volumetric apparent diffusion coefficient histogram analysis in term neonatal asphyxia treated with hypothermia

OBJECTIVES

Our aim is to estimate the long-term neurological sequelae and prognosis in term neonatal asphyxia treated with hypothermia via volumetric apparent diffusion coefficient (ADC) map histogram analysis (HA).

METHODS

Brain MRI studies of 83 term neonates with asphyxia who received whole-body hypothermia treatment and examined between postnatal (PN) fourth and sixth days were retrospectively re-evaluated by 2 radiologists. Volumetric HA was performed for the areas frequently affected in deep and superficial asphyxia (thalamus, lentiform nucleus, posterior limb of internal capsule, corpus callosum forceps major, and perirolandic cortex-subcortical white matter) on ADC map. The quantitative ADC values were obtained separately for each region. Qualitative-visual (conventional) MRI findings were also re-evaluated. Neonates were examined neurodevelopmentally according to the Revised Brunet-Lezine scale. The distinguishability of long-term neurodevelopmental outcomes was statistically investigated.

RESULTS

With HA, the adverse neurodevelopmental outcomes could only be distinguished from mild-moderated impairment and normal development at the thalamus with 10th percentile ADC (P = .02 and P = .03, respectively) and ADCmin (P = .03 and P = .04, respectively). Also with the conventional MRI findings, adverse outcome could be distinguished from mild-moderated impairment (P = .04) and normal development (P = .04) via cytotoxic oedema of the thalamus, corpus striatum, and diffuse cerebral cortical.

CONCLUSION

The long-term adverse neurodevelopmental outcomes in newborns with asphyxia who received whole-body hypothermia treatment can be estimated similarly with volumetric ADC-HA and the conventional assessment of the ADC map.

ADVANCES IN KNOWLEDGE

This study compares early MRI ADC-HA with neurological sequelae in term newborns with asphyxia who received whole-body hypothermia treatment. We could not find any significant difference in predicting adverse neurological sequelae between the visual-qualitative evaluation of the ADC map and HA.

Volumetric changes in brain MRI of infants with hypoxic-ischemic encephalopathy and abnormal neurodevelopment who underwent therapeutic hypothermia

BACKGROUND

Hypoxic-ischemic encephalopathy (HIE) is a severe neonatal complication that can result in 40-60 % of long-term morbidity. Magnetic Resonance Imaging (MRI) is a noninvasive method which is usually performed before discharge to visually assess acquired cerebral lesions associated with HIE and severity of lesions possibly providing a guide for detecting adverse outcomes. This study aims to evaluate the impact of HIE on brain volume changes observed in MRI scans performed at a mean 10 days of life, which can serve as a prognostic indicator for abnormal neurodevelopmental (ND) outcomes at 18-24 months among HIE infants.

METHODS

We retrospectively identified a cohort of HIE patients between June 2013 and March 2017. The inclusion criteria for therapeutic hypothermia (TH) were a gestational age ≥35 weeks, a birth weight ≥1800 g, and the presence of ≥ moderate HIE. Brain MRI was performed at a mean 10 days of life and brain volumes (total brain volume, cerebral volume, cerebellar volume, brain stem volume, and ventricle volume) were measured for quantitative assessment. At 18-24 months, the infants returned for follow-up evaluations, during which their cognitive, language, and motor skills were assessed using the Bayley Scales of Infant and Toddler Development III.

RESULTS

The study recruited a total of 240 infants between 2013 and 2017 for volumetric brain MRI evaluation. Among these, 83 were normal control infants, 107 were TH-treated HIE infants and 37 were HIE infants who did not receive TH due to contraindications. Clinical evaluation was further proceeded. We compared the brain volumes between the normal control infants (n = 83) with normal ND but TH-treated HIE infants (n = 76), abnormal ND TH-treated HIE infants (n = 31), and the severe HIE MRI group with no TH (n = 37). The abnormal ND TH-treated HIE infants demonstrated a significant decrease in brainstem volume and an increase in ventricle size (p < 0.001) (Table 4). Lastly, the severe brain MRI group who did not receive TH showed significantly smaller brain stem (p = 0.006), cerebellar (p = 0.006) and cerebrum volumes (p = 0.027), accompanied by larger ventricular size (p = 0.013) compared to the normal control group (Table 5).

CONCLUSION

In addition to assessing the location of brain injuries in MRI scans, the reduction in brain stem volume coupled with an increase in ventricular volume in HIE infants may serve as a biomarker indicating severe HIE and adverse long-term ND outcomes among HIE infants who either received therapeutic hypothermia (TH) treatment or not.

MRI pattern recognition in white matter disease

Magnetic resonance imaging (MRI) pattern recognition is a powerful tool for quick diagnosis of genetic and acquired white matter disorders. In many cases, distribution and character of white matter abnormalities directly point to a specific diagnosis and guide confirmatory testing. Knowledge of normal brain development is essential to interpret white matter changes in young children. MRI is also used for disease staging and treatment decisions in leukodystrophies and acquired disorders as multiple sclerosis, and as a biomarker to follow treatment effects.

Neuroquantification enhances the radiological evaluation of term neonatal hypoxic-ischaemic cerebral injuries

Background

Injury patterns in hypoxic-ischaemic brain injury (HIBI) are well recognised but there are few studies evaluating cerebral injury using neuroquantification models.

Objectives

Quantification of brain volumes in a group of patients with clinically determined cerebral palsy.

Method

In this retrospective study, 297 children with cerebral palsy were imaged for suspected HIBI with analysis of various cerebral substrates. Of these, 96 children over the age of 3 years with a clinical diagnosis of cerebral palsy and abnormal MRI findings underwent volumetric analyses using the NeuroQuant® software solution. The spectrum of volumetric changes and the differences between the various subtypes (and individual subgroups) of HIBI were compared.

Results

Compared with the available normative NeuroQuant® database, the average intracranial volume was reduced to the 1st percentile in all patient groups (p < 0.001). Statistically significant differences were observed among the types and subgroups of HIBI. Further substrate volume reductions were identified and described involving the thalami, brainstem, hippocampi, putamina and amygdala. The combined volumes of five regions of interest (frontal pole, putamen, hippocampus, brainstem and paracentral lobule) were consistently reduced in the Rolandic basal ganglia-thalamus (RBGT) subtype.

Conclusion

This study determined a quantifiable reduction of intracranial volume in all subtypes of HIBI and predictable selective cerebral substrate volume reduction in subtypes and subgroups. In the RBGT subtype, a key combination of five substrate injuries was consistently noted, and thalamic, occipital lobe and brainstem volume reduction was also significant when compared to the watershed subtype.

Contribution

This study demonstrates the value of integrating an artificial intelligence programme into the radiologists' armamentarium serving to quantify brain injuries more accurately in HIBI. Going forward this will be an inevitable evolution of daily radiology practice in many fields of medicine, and it would be beneficial for radiologists to embrace these technological innovations.

Safety and efficacy of therapeutic hypothermia in neonates with mild hypoxic-ischemic encephalopathy

BACKGROUND

Though there has been an increase in the number of neonates with hypoxic-ischemic encephalopathy (HIE) treated by therapeutic hypothermia (TH) in recent years, the effect of therapeutic hypothermia on mild HIE neonates is still uncertain.

OBJECTIVES

This study aims to explore the safety and efficacy of therapeutic hypothermia in neonates with mild HIE.

METHODS

Retrospectively collected between January 2010 to December 2022 at Children's Hospital of Fudan University, neonates with mild HIE were divided into TH and non-TH groups. Clinical data of the mild HIE neonates and their mothers' general information during pregnancy were collected. SPSS 23.0 was used to compare the general condition, the incidence of adverse events, and efficacy in the two groups.

RESULTS

A total of 71 neonates with mild HIE were included, including 31 in the TH group and 40 in the non-TH group. Compared with the non-TH group, the TH group had significantly lower 5-minute Apgar scores [6 (5-7) points vs. 7 (5-8) points, p = 0.033 ], but a higher rate of tracheal intubation at birth (68%, 21/31 vs. 40%, 16/40, p = 0.02), a higher rate of chest compressions > 30 s (39%, 12/31 vs. 15%, 6/40, p = 0.023), the later initiation enteral feeding [4 (3-4) days vs. 1 (1-2) days, p < 0.001], a higher usage rate of analgesic and sedative drugs (45%, 14/31 vs. 18%, 7/40, p = 0.011) and the longer hospital stay [12.5 (11-14) days vs. 9 (7-13.9) days, p = 0.003]. There was no death in 71 mild HIE neonates. TH group had lower incidence of brain injury (16%, 5/31 vs. 43%, 17/40, p = 0.017) and encephalopathy progression (10%, 3/31 vs. 45%, 18/40, p = 0.001) than the non-TH group. There was no statistical significance in the incidence of adverse events between the two groups.

CONCLUSION

Therapeutic hypothermia can reduce the incidence of brain injury in neonates with mild HIE.

Clinical practice

Basal ganglia and thalamus (BGT) hypoxic-ischaemic brain injury is currently the most contentious issue in cerebral palsy (CP) litigation in South Africa (SA), and merits a consensus response based on the current available international literature. BGT pattern injury is strongly associated with a preceding perinatal sentinel event (PSE), which has a sudden onset and is typically unforeseen and unpreventable. Antepartum pathologies may result in fetal priming, leading to vulnerability to BGT injury by relatively mild hypoxic insults. BGT injury may uncommonly follow a gradual-onset fetal heart rate deterioration pattern, of duration ≥1 hour. To prevent BGT injury in a clinical setting, the interval from onset of PSE to delivery must be short, as little as 10 - 20 minutes. This is difficult to achieve in any circumstances in SA. Each case needs holistic, multidisciplinary, unbiased review of all available antepartum, intrapartum and postpartum and childhood information, aiming at fair resolution without waste of time and resources.

Imaging of congenital and developmental cystic lesions of the brain: a narrative review

INTRODUCTION

Congenital and developmental intracranial cysts represent a large heterogenous group with varied presentations and etiologies. They can range from normal variants to pathologic lesions often associated with known congenital syndromes or acquired insults. While some are incidentally found, others are symptomatic or may become symptomatic over time. The preferred type of neuroimaging for timely diagnosis helps determine appropriate management and treatment, if indicated.

AREAS COVERED

In this narrative review article, authors present a comprehensive description of developmental cystic lesions. Imaging descriptions are provided for each type of cystic lesion as well as several representative images.

EXPERT OPINION

As advanced neuroimaging techniques become more ubiquitous in clinical use, more light may be shed on the natural history of certain intracranial cystic lesions throughout the lifespan. This includes prenatal imaging for early identification and prognostication to surveillance imaging into advanced age to ascertain associations of certain cystic lesions with age-related cognitive dysfunction.

Creatine in the fetal brain: A regional investigation of acute global hypoxia and creatine supplementation in a translational fetal sheep model

Background

Creatine supplementation during pregnancy is a promising prophylactic treatment for perinatal hypoxic brain injury. Previously, in near-term sheep we have shown that fetal creatine supplementation reduces cerebral metabolic and oxidative stress induced by acute global hypoxia. This study investigated the effects of acute hypoxia with or without fetal creatine supplementation on neuropathology in multiple brain regions.

Methods

Near-term fetal sheep were administered continuous intravenous infusion of either creatine (6 mg kg^-1 h^-1) or isovolumetric saline from 122 to 134 days gestational age (dGA; term is approx. 145 dGA). At 131 dGA, global hypoxia was induced by a 10 min umbilical cord occlusion (UCO). Fetuses were then recovered for 72 h at which time (134 dGA) cerebral tissue was collected for either RT-qPCR or immunohistochemistry analyses.

Results

UCO resulted in mild injury to the cortical gray matter, thalamus and hippocampus, with increased cell death and astrogliosis and downregulation of genes involved in regulating injury responses, vasculature development and mitochondrial integrity. Creatine supplementation reduced astrogliosis within the corpus callosum but did not ameliorate any other gene expression or histopathological changes induced by hypoxia. Of importance, effects of creatine supplementation on gene expression irrespective of hypoxia, including increased expression of anti-apoptotic (BCL-2) and pro-inflammatory (e.g., MPO, TNFa, IL-6, IL-1β) genes, particularly in the gray matter, hippocampus, and striatum were identified. Creatine treatment also effected oligodendrocyte maturation and myelination in white matter regions.

Conclusion

While supplementation did not rescue mild neuropathology caused by UCO, creatine did result in gene expression changes that may influence in utero cerebral development.

Neuroprotective and Regenerative Effects of Growth Hormone (GH) in the Embryonic Chicken Cerebral Pallium Exposed to Hypoxic-Ischemic (HI) Injury

Prenatal hypoxic−ischemic (HI) injury inflicts severe damage on the developing brain provoked by a pathophysiological response that leads to neural structural lesions, synaptic loss, and neuronal death, which may result in a high risk of permanent neurological deficits or even newborn decease. It is known that growth hormone (GH) can act as a neurotrophic factor inducing neuroprotection, neurite growth, and synaptogenesis after HI injury. In this study we used the chicken embryo to develop both in vitro and in vivo models of prenatal HI injury in the cerebral pallium, which is the equivalent of brain cortex in mammals, to examine whether GH exerts neuroprotective and regenerative effects in this tissue and the putative mechanisms involved in these actions. For the in vitro experiments, pallial cell cultures obtained from chick embryos were incubated under HI conditions (<5% O2, 1 g/L glucose) for 24 h and treated with 10 nM GH, and then collected for analysis. For the in vivo experiments, chicken embryos (ED14) were injected in ovo with GH (2.25 µg), exposed to hypoxia (12% O2) for 6 h, and later the pallial tissue was obtained to perform the studies. Results show that GH exerted a clear anti-apoptotic effect and promoted cell survival and proliferation in HI-injured pallial neurons, in both in vitro and in vivo models. Neuroprotective actions of GH were associated with the activation of ERK1/2 and Bcl-2 signaling pathways. Remarkably, GH protected mature neurons that were particularly harmed by HI injury, but was also capable of stimulating neural precursors. In addition, GH stimulated restorative processes such as the number and length of neurite outgrowth and branching in HI-injured pallial neurons, and these effects were blocked by a specific GH antibody, thus indicating a direct action of GH. Furthermore, it was found that the local expression of several synaptogenic markers (NRXN1, NRXN3, GAP-43, and NLG1) and neurotrophic factors (GH, BDNF, NT-3, IGF-1, and BMP4) were increased after GH treatment during HI damage. Together, these results provide novel evidence supporting that GH exerts protective and restorative effects in brain pallium during prenatal HI injury, and these actions could be the result of a joint effect between GH and endogenous neurotrophic factors. Also, they encourage further research on the potential role of GH as a therapeutic complement in HI encephalopathy treatments.

Thalamus L-Sign: A Potential Biomarker of Neonatal Partial, Prolonged Hypoxic-Ischemic Brain Injury or Hypoglycemic Encephalopathy?

BACKGROUND AND PURPOSE

Considerable overlap exists in the MR imaging features of hypoglycemic injury and hypoxic-ischemic brain injury, with similar predilections for the occipital and parietal lobes. In partial, prolonged hypoxia-ischemia, there is cortical destruction at the interarterial watershed zones, and in concomitant hypoglycemia and hypoxia-ischemia, an exaggerated final common pathway injury occurs. We interrogated secondary white matter tract-based thalamic injury as a tool to separate pure injuries in each group.

MATERIALS AND METHODS

A retrospective observational study of the MRIs of 320 children with a history of hypoxia-ischemia and/or hypoglycemia was undertaken with 3 major subgroups: 1) watershed-type hypoxic-ischemic injury, 2) neonatal hypoglycemia, and 3) both perinatal hypoxia-ischemia and proved hypoglycemia. Cerebral and thalamic injuries were assessed, particularly hyperintensity of the posterolateral margin of the thalami. A modified Poisson regression model was used to assess factors associated with such thalamic injury.

RESULTS

Parieto-occipital injuries occurred commonly in patients with hypoglycemia and/or hypoxia-ischemia. Eighty-five of 99 (86%) patients with partial, prolonged hypoxia-ischemia exhibited the thalamus L-sign. This sign was also observed in patients who had both hypoglycemia and hypoxia-ischemia, predominantly attributable to the latter. Notably, the risk of a thalamus L-sign injury was 2.79 times higher when both the parietal and occipital lobes were injured compared with when they were not involved (95% CI, 1.25-6.23; P = .012). The thalamus L-sign was not depicted in patients with pure hypoglycemia.

CONCLUSIONS

We propose the thalamus L-sign as a biomarker of partial, prolonged hypoxia-ischemia, which is exaggerated in combined hypoglycemic/hypoxic-ischemic injury.

Associations between neonatal hypoglycaemia and brain volumes, cortical thickness and white matter microstructure in mid-childhood: An MRI study

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Neonatal hypoglycaemia is associated with damage to the brain in the acute phase.

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In mid-childhood, neonatal hypoglycaemia is associated with smaller brain regions.

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Deep grey matter regions such as the caudate and thalamus are implicated.

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Children with neonatal hypoglycemia had smaller occipital lobe cortical thickness.

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Grey matter may be especially vulnerable to long-term effects of neonatal hypoglycemia.

Neonatal hypoglycaemia is a common metabolic disorder that may cause brain damage, most visible in parieto-occipital regions on MRI in the acute phase. However, the long term effects of neonatal hypoglycaemia on the brain are not well understood. We investigated the association between neonatal hypoglycaemia and brain volumes, cortical thickness and white matter microstructure at 9–10 years.

Children born at risk of neonatal hypoglycaemia at ≥ 36 weeks’ gestation who took part in a prospective cohort study underwent brain MRI at 9–10 years. Neonatal hypoglycaemia was defined as at least one hypoglycaemic episode (at least one consecutive blood glucose concentration < 2.6 mmol/L) or interstitial episode (at least 10 min of interstitial glucose concentrations < 2.6 mmol/L). Brain volumes and cortical thickness were computed using Freesurfer. White matter microstructure was assessed using tract-based spatial statistics.

Children who had (n = 75) and had not (n = 26) experienced neonatal hypoglycaemia had similar combined parietal and occipital lobe volumes and no differences in white matter microstructure at nine years of age. However, those who had experienced neonatal hypoglycaemia had smaller caudate volumes (mean difference: −557 mm³, 95% confidence interval (CI), −933 to −182, p = 0.004) and smaller thalamus (−0.03%, 95%CI, −0.06 to 0.00; p = 0.05) and subcortical grey matter (−0.10%, 95%CI −0.20 to 0.00, p = 0.05) volumes as percentage of total brain volume, and thinner occipital lobe cortex (−0.05 mm, 95%CI −0.10 to 0.00, p = 0.05) than those who had not. The finding of smaller caudate volumes after neonatal hypoglycaemia was consistent across analyses of pre-specified severity groups, clinically detected hypoglycaemic episodes, and severity and frequency of hypoglycaemic events.

Neonatal hypoglycaemia is associated with smaller deep grey matter brain regions and thinner occipital lobe cortex but not altered white matter microstructure in mid-childhood.

Brain Magnetic Resonance Imaging Findings in Infantile Spasms

Background: Infantile spasms are an age-specific epileptic disorder. They occur in infancy and early childhood. They can be caused by multiple etiologies. Structural abnormalities represent an important cause of infantile spasms. Brain magnetic resonance imaging (MRI) is one of the integral modalities in the evaluation of this condition. Purpose: The aim of this study is to review and analyze the clinical characteristics and brain MRI findings in a cohort of children diagnosed with infantile spasms. Material and Methods: A cohort of fifty-six children diagnosed with infantile spasms in infancy and early childhood was included. All of them underwent brain MRI for evaluation. The study was conducted in the period from January 2016 to January 2020. Results: Females comprised 57% of the cohort. The mean age for seizure onset was 5.9 months (SD 2.7). Forty-one patients (73%) had active epilepsy, and 51% were diagnosed with global developmental delay. Consanguinity was present in 59% of the cohort. Most of the follow-up MRIs showed structural abnormalities (84%). Hypoxia was reported in 17% of MRIs. Malformations of cortical development were seen in five patients. Brain MRI findings were normal in 16% of patients, and delayed myelination was seen in nineteen patients. Most of the children with active epilepsy (64%) and developmental delay (82%) had an abnormal brain MRI. It was noticed that abnormal second brain MRIs were more likely to be associated with active epilepsy and developmental delay (p = 0.05). Conclusions: Brain MRI is an integral part of infantile spasms’ clinical evaluation. Infantile spasms and abnormal brain MRI can be associated with active epilepsy and global developmental delay.

A proposed magnetic resonance imaging grading system for the spectrum of central neonatal parasagittal hypoxic–ischaemic brain injury

Aim

To describe the spectrum of parasagittal injury on MRI studies performed on children following severe perinatal term hypoxia–ischaemia, using a novel MRI grading system, and propose a new central pattern correlated with neuropathologic features.

Methods

MR scans of 297 patients with perinatal term hypoxia–ischaemia were evaluated for typical patterns of brain injury. A total of 83 patients that demonstrated the central/basal ganglia–thalamus and perirolandic pattern of injury were categorised according to the degree of severity. The perirolandic injury was graded by the degree of interhemispheric widening, paracentral lobule involvement and perirolandic cortex destruction leading to a tiered categorisation. Of these 83 patients, 19 had the most severe subtype of injury. A detailed analysis of the clinical data of a subset of 11 of these 19 patients was conducted.

Results

We demonstrated the mild subtype in 21/83(25%), the moderate subtype in 22/83(27%) and the severe subtype in 21/83(25%). A fourth pattern was identified in 19/83(23%) patients with a diamond-shaped expansion of the interhemispheric fissure, concomitant thalamic, putaminal, hippocampal and other smaller substrate involvement indicative of the most destructive subtype.

Conclusions

We propose a new MR grading system of injury at the parasagittal perirolandic region related to severe, sustained central perinatal term hypoxia–ischaemia. We also introduce a previously undescribed pattern of injury, the most severe form of this spectrum, seen especially after prolongation of the second stage of labour. This constellation of high metabolic substrate, targeted tissue destruction is consistently demonstrated by MRI, termed the massive paramedian injury pattern.

Wavelet-based neurovascular coupling can predict brain abnormalities in neonatal encephalopathy

BACKGROUND

Hypoxic-ischemic encephalopathy (HIE) is a leading cause of morbidity and mortality in neonates, but quantitative methods to predict outcomes early in their course of illness remain elusive. Real-time physiologic biomarkers of neurologic injury are needed in order to predict which neonates will benefit from therapies. Neurovascular coupling (NVC) describes the correlation of neural activity with cerebral blood flow, and the degree of impairment could predict those at risk for poor outcomes.

OBJECTIVE

To determine if neurovascular coupling (NVC) calculated in the first 24-hours of life based on wavelet transform coherence analysis (WTC) of near-infrared spectroscopy (NIRS) and amplitude-integrated electroencephalography (aEEG) can predict abnormal brain MRI in neonatal HIE.

METHODS

WTC analysis was performed between dynamic oscillations of simultaneously recorded aEEG and cerebral tissue oxygen saturation (SctO2) signals for the first 24 h after birth. The squared cross-wavelet coherence, R2, of the time-frequency domain described by the WTC, is a localized correlation coefficient (ranging between 0 and 1) between these two signals in the time-frequency domain. Statistical analysis was based on Monte Carlo simulation with a 95% confidence interval to identify the time-frequency areas from the WTC scalograms. Brain MRI was performed on all neonates and classified as normal or abnormal based on an accepted classification system for HIE. Wavelet metrics of % significant SctO2-aEEG coherence was compared between the normal and abnormal MRI groups.

RESULT

This prospective study recruited a total of 36 neonates with HIE. A total of 10 had an abnormal brain MRI while 26 had normal MRI. The analysis showed that the SctO2-aEEG coherence between the group with normal and abnormal MRI were significantly different (p = 0.0007) in a very low-frequency (VLF) range of 0.06-0.2 mHz. Using receiver operating characteristic (ROC) curves, the use of WTC-analysis of NVC had an area under the curve (AUC) of 0.808, and with a cutoff of 10% NVC. Sensitivity was 69%, specificity was 90%, positive predictive value (PPV) was 94%, and negative predictive value (NPV) was 52% for predicting brain injury on MRI. This was superior to the clinical Total Sarnat score (TSS) where AUC was 0.442 with sensitivity 61.5%, specificity 30%, PPV 75%, and NPV 31%.

CONCLUSION

NVC is a promising neurophysiological biomarker in neonates with HIE, and in our prospective cohort was superior to the clinical Total Sarnat score for prediction of abnormal brain MRI.

Effects of Lipoic Acid on Ischemia-Reperfusion Injury

Ischemia-reperfusion (I/R) injury often occurred in some pathologies and surgeries. I/R injury not only harmed to physiological functions of corresponding organ and tissue but also induced multiple tissue or organ dysfunctions (even these in distant locations). Although the reperfusion of blood attenuated I/R injury to a certain degree, the risk of secondary damages was difficult to be controlled and it even caused failures of these tissues and organs. Lipoic acid (LA), as an endogenous active substance and a functional agent in food, owns better safety and effects in our body (e.g., enhancing antioxidant activity, improving cognition and dementia, controlling weight, and preventing multiple sclerosis, diabetes complication, and cancer). The literature searching was conducted in PubMed, Embase, Cochrane Library, Web of Science, and SCOPUS from inception to 20 May 2021. It had showed that endogenous LA was exhausted in the process of I/R, which further aggravated I/R injury. Thus, supplements with LA timely (especially pretreatments) may be the prospective way to prevent I/R injury. Recently, studies had demonstrated that LA supplements significantly attenuated I/R injuries of many organs, though clinic investigations were short at present. Hence, it was urgent to summarize these progresses about the effects of LA on different I/R organs as well as the potential mechanisms, which would enlighten further investigations and prepare for clinic applications in the future.

Quantitative Susceptibility Mapping of Venous Vessels in Neonates with Perinatal Asphyxia

BACKGROUND AND PURPOSE

Cerebral venous oxygen saturation can be used as an indirect measure of brain health, yet it often requires either an invasive procedure or a noninvasive technique with poor sensitivity. We aimed to test whether cerebral venous oxygen saturation could be measured using quantitative susceptibility mapping, an MR imaging technique, in 3 distinct groups: healthy term neonates, injured term neonates, and preterm neonates.

MATERIALS AND METHODS

We acquired multiecho gradient-echo MR imaging data in 16 neonates with perinatal asphyxia and moderate or severe hypoxic-ischemic encephalopathy (8 term age: average, 40.0 [SD, 0.8]  weeks' gestational age; 8 preterm, 33.5 [SD, 2.0]  weeks' gestational age) and in 8 healthy term-age controls (39.3 [SD, 0.6] weeks, for a total of n = 24. Data were postprocessed as quantitative susceptibility mapping images, and magnetic susceptibility was measured in cerebral veins by thesholding out 99.95% of lower magnetic susceptibility values.

RESULTS

The mean magnetic susceptibility value of the cerebral veins was found to be 0.36 (SD, 0.04) ppm in healthy term neonates, 0.36 (SD, 0.06) ppm in term injured neonates, and 0.29 (SD, 0.04) ppm in preterm injured neonates. Correspondingly, the derived cerebral venous oxygen saturation values were 73.6% (SD, 2.8%), 71.5% (SD, 7.4%), and 72.2% (SD, 5.9%). There was no statistically significant difference in cerebral venous oxygen saturation among the 3 groups (P = .751).

CONCLUSIONS

Quantitative susceptibility mapping-derived oxygen saturation values in preterm and term neonates agreed well with values in past literature. Cerebral venous oxygen saturation in preterm and term neonates with hypoxic-ischemic encephalopathy, however, was not found to be significantly different between neonates or healthy controls.

Clinical seizures and unfavorable brain MRI patterns in neonates with hypoxic ischemic encephalopathy

The aim was to examine whether clinical seizures and amplitude-integrated electroencephalogram (aEEG) patterns in infants with hypoxic ischemic encephalopathy (HIE) can predict the extent of brain injury on magnetic resonance images (MRI) and the long-term neurodevelopmental outcomes at 18∼24 months of age.HIE infants who underwent therapeutic hypothermia (TH) between June 2014 and March 2017 were included in this study. Infants with clinical seizure were analyzed for aEEG patterns and the extent of brain injury on MRI findings. Clinical seizure, aEEG, and brain MRI were assessed and compared with neurodevelopmental outcomes at 18∼24 months of age.Among the 97 HIE infants enrolled in this study with brain MRI scans, 78 (73.1%) TH-treated HIE infants exhibited clinical seizures. More abnormalities on a EEGs and more significant use of first and second antiepileptic drugs (AEDs) were significantly higher in the clinical-seizure group with longer hospitalized days. At a corrected 18 to 24 months of age, HIE infants in the clinical-seizure group with more extension of injury lesions on diffusion-weighted MRI scans exhibited significantly more delayed neurodevelopment. A risk factor analysis indicated that male infants who stayed in the hospital for more than 11 days were at a higher risk of having clinical seizures. The lesion size in MRI greater than 37 pixels was a risk factor with an 81.8% accuracy.Seizures in HIE infants may predict abnormal brain MRI scans and abnormal neurodevelopment at 18 to 24 months of age.

Predictive Values of Location and Volumetric MRI Injury Patterns for Neurodevelopmental Outcomes in Hypoxic-Ischemic Encephalopathy Neonates

Hypoxic-ischemic encephalopathy (HIE) is a severe neonatal complication with up to 40–60% long-term morbidity. This study evaluates the distribution and burden of MRI changes as a prognostic indicator of neurodevelopmental (ND) outcomes at 18–24 months in HIE infants who were treated with therapeutic hypothermia (TH). Term or late preterm infants who were treated with TH for HIE were analyzed between June 2012 and March 2016. Brain MRI scans were obtained from 107 TH treated infants. For each infant, diffusion weighted brain image (DWI) sequences from a 3T Siemens scanner were obtained for analysis. Of the 107 infants, 36 of the 107 infants (33.6%) had normal brain MR images, and 71 of the 107 infants (66.4%) had abnormal MRI findings. The number of clinical seizures was significantly higher in the abnormal MRI group (p < 0.001) than in the normal MRI group. At 18–24 months, 76 of the 107 infants (70.0%) showed normal ND stages, and 31 of the 107 infants (29.0%) exhibited abnormal ND stages. A lesion size count >500 was significantly associated with abnormal ND. Similarly, the total lesion count was larger in the abnormal ND group (14.16 vs. 5.29). More lesions in the basal ganglia (BG) and thalamus areas and a trend towards more abnormal MRI scans were significantly associated with abnormal ND at 18–24 months. In addition to clinical seizure, a larger total lesion count and lesion size as well as lesion involvement of the basal ganglia and thalamus were significantly associated with abnormal neurodevelopment at 18–24 months.

A pictorial review of the pathophysiology and classification of the magnetic resonance imaging patterns of perinatal term hypoxic ischemic brain injury - What the radiologist needs to know…

This article provides a correlation of the pathophysiology and magnetic resonance imaging (MRI) patterns identified on imaging of children with hypoxic ischemic brain injury (HIBI). The purpose of this pictorial review is to empower the reading radiologist with a simplified classification of the patterns of cerebral injury matched to images of patients demonstrating each subtype. A background narrative literature review was undertaken of the regional, continental and international databases looking at specific patterns of cerebral injury related to perinatal HIBI. In addition, a database of MRI studies accumulated over a decade (including a total of 314 studies) was analysed and subclassified into the various patterns of cerebral injury. Selected cases were annotated to highlight the areas involved and for ease of identification of the affected substrate in daily practice.

KEYWORDS

Hypoxic ischemic encephalopathy; Magnetic resonance imaging; Acute profound; Partial prolonged; Hypoxic ischemic brain injury; Ulegyria; Multicystic; Encephalopathy.

Volume reduction of caudate nucleus is associated with movement coordination deficits in patients with hippocampal atrophy due to perinatal hypoxia-ischaemia

Acute sentinel hypoxia-ischaemia in neonates can target the hippocampus, mammillary bodies, thalamus, and the basal ganglia. Our previous work with paediatric patients with a history of hypoxia-ischaemia has revealed hippocampal and diencephalic damage that impacts cognitive memory. However, the structural and functional status of other brain regions vulnerable to hypoxia-ischaemia, such as the basal ganglia, has not been investigated in these patients. Furthermore, it is not known whether there are any behavioural sequelae of such damage, especially in patients with no diagnosis of neurological disorder. Based on the established role of the basal ganglia and the thalamus in movement coordination, we studied manual motor function in 20 participants exposed to neonatal hypoxia-ischaemia, and a group of 17 healthy controls of comparable age. The patients' handwriting speed and accuracy was within the normal range (Detailed Assessment of Speed of Handwriting), and their movement adaptation learning (Rotary Pursuit task) was comparable to the control group's performance. However, as a group, patients showed an impairment in the Grooved Pegboard task and a trend for impairment in speed of movement while performing the Rotary Pursuit task, suggesting that some patients have subtle deficits in fine, complex hand movements. Voxel-based morphometry and volumetry showed bilateral reduction in grey matter volume of the thalamus and caudate nucleus. Reduced volumes in the caudate nucleus correlated across patients with performance on the Grooved Pegboard task. In summary, the fine movement coordination deficit affecting the hand and the wrist in patients exposed to early hypoxic-ischaemic brain injury may be related to reduced volumes of the caudate nucleus, and consistent with anecdotal parental reports of clumsiness and coordination difficulties in this cohort.

The enigmatic fetal subplate compartment forms an early tangential cortical nexus and provides the framework for construction of cortical connectivity

The most prominent transient compartment of the primate fetal cortex is the deep, cell-sparse, synapse-containing subplate compartment (SPC). The developmental role of the SPC and its extraordinary size in humans remain enigmatic. This paper evaluates evidence on the development and connectivity of the SPC and discusses its role in the pathogenesis of neurodevelopmental disorders. A synthesis of data shows that the subplate becomes a prominent compartment by its expansion from the deep cortical plate (CP), appearing well-delineated on MR scans and forming a tangential nexus across the hemisphere, consisting of an extracellular matrix, randomly distributed postmigratory neurons, multiple branches of thalamic and long corticocortical axons. The SPC generates early spontaneous non-synaptic and synaptic activity and mediates cortical response upon thalamic stimulation. The subplate nexus provides large-scale interareal connectivity possibly underlying fMR resting-state activity, before corticocortical pathways are established. In late fetal phase, when synapses appear within the CP, transient the SPC coexists with permanent circuitry. The histogenetic role of the SPC is to provide interactive milieu and capacity for guidance, sorting, "waiting" and target selection of thalamocortical and corticocortical pathways. The new evolutionary role of the SPC and its remnant white matter neurons is linked to the increasing number of associative pathways in the human neocortex. These roles attributed to the SPC are regulated using a spatiotemporal gene expression during critical periods, when pathogenic factors may disturb vulnerable circuitry of the SPC, causing neurodevelopmental cognitive circuitry disorders.

The Influence of Various Cerebral and Extracerebral Pathologies on Apparent Diffusion Coefficient Values in the Fetal Brain

BACKGROUND AND PURPOSE

The changing MRI signal accompanying brain maturation in fetal brains can be quantified on apparent diffusion coefficient (ADC) maps. Deviations from the natural course of ADC values may reflect structural pathology. The purpose of this study was to determine the influence of fetal pathologies on the ADC values in different regions of the fetal brain and their evolution with increasing gestational age.

METHODS

This was a retrospective study of 291 fetuses evaluated between the 14th and the 40th week of gestation using diffusion‐weighted imaging (DWI). Fetuses with normal MRI findings but sonographically suspected pathology or fetuses with abnormalities not affecting the brain were analyzed in the control group and compared to fetuses suffering from different pathologies like hydrocephalus/ventriculomegaly, brain malformations, infections, ischemia/hemorrhage, diaphragmatic hernias, and congenital heart disease. Pairwise ADC measurements in each side of the white matter (WM) of the frontal, parietal, and occipital lobes, in the basal ganglia and the cerebellum, as well as a single measurement in the pons were performed and were plotted against gestational age.

RESULTS

In the control group, brain maturation followed a defined gradient, resulting in lower ADC values in the most mature regions. Each disorder group experienced abnormal patterns of evolution of the ADC values over time deviating from the expected course.

CONCLUSIONS

The ADC values in different regions of the fetal brain and their evolution with increasing gestational age are influenced by pathologies compromising the cerebral maturation.

TRPM7 Mediates Neuronal Cell Death Upstream of Calcium/Calmodulin-Dependent Protein Kinase II and Calcineurin Mechanism in Neonatal Hypoxic-Ischemic Brain Injury

Transient receptor potential melastatin 7 (TRPM7), a calcium-permeable, ubiquitously expressed ion channel, is critical for axonal development, and mediates hypoxic and ischemic neuronal cell death in vitro and in vivo. However, the downstream mechanisms underlying the TRPM7-mediated processes in physiology and pathophysiology remain unclear. In this study, we employed a mouse model of hypoxic-ischemic brain cell death which mimics the pathophysiology of hypoxic-ischemic encephalopathy (HIE). HIE is a major public health issue and an important cause of neonatal deaths worldwide; however, the available treatments for HIE remain limited. Its survivors face life-long neurological challenges including mental retardation, cerebral palsy, epilepsy and seizure disorders, motor impairments, and visual and auditory impairments. Through a proteomic analysis, we identified calcium/calmodulin-dependent protein kinase II (CaMKII) and phosphatase calcineurin as potential mediators of cell death downstream from TRPM7 activation. Further analysis revealed that TRPM7 mediates cell death through CaMKII, calmodulin, calcineurin, p38, and cofilin cascade. In vivo, we found a significant reduction of brain injury and improvement of short- and long-term functional outcomes after HI after administration of specific TRPM7 blocker waixenicin A. Our data demonstrate a molecular mechanism of TRPM7-mediated cell death and identifies TRPM7 as a promising therapeutic and drug development target for HIE.

Markers of perinatal hypoxia-ischaemia and neurological injury: assessing the impact of insult duration

Hypoxic-ischaemic insults occurring during or after birth can cause both acute and long-term neurological impairment. The duration of the insult is a critical factor, but most published reports of duration have important limitations. After the onset of a persistent bradycardia in 125 term born infants, abnormal outcomes occurred in two by 10 minutes, in 12 out of 47 (26%) delivered between 11 and 20 minutes, and in 55 out of 65 (85%) delivered after 20 minutes. Series with unspecified gestation or including infants born preterm give comparable results in over 500 additional cases. Before 20 minutes there was little correlation with severity, while after 20 minutes most were severely impaired. Limited neuroimaging data suggest that damage restricted to the basal ganglia and thalamus may begin to occur after 10 minutes, associated Rolandic damage after 15 minutes, and other cortical involvement after 20 minutes. Associated white matter damage can occur after any duration. There were little data for other patterns of damage. WHAT THIS PAPER ADDS: Some term born infants can withstand 20 minutes of fetal bradycardia without acute or chronic damage. Durations in humans are not the same as in animal models.

Therapeutic hypothermia initiated within 6 hours of birth is associated with reduced brain injury on MR biomarkers in mild hypoxic-ischaemic encephalopathy: a non-randomised cohort study

OBJECTIVE

To examine the effect of therapeutic hypothermia on MR biomarkers and neurodevelopmental outcomes in babies with mild hypoxic-ischaemic encephalopathy (HIE).

DESIGN

Non-randomised cohort study.

SETTING

Eight tertiary neonatal units in the UK and the USA.

PATIENTS

47 babies with mild HIE on NICHD neurological examination performed within 6 hours after birth.

INTERVENTIONS

Whole-body cooling for 72 hours (n=32) or usual care (n=15; of these 5 were cooled for <12 hours).

MAIN OUTCOME MEASURES

MRI and MR spectroscopy (MRS) within 2 weeks after birth, and a neurodevelopmental outcome assessment at 2 years.

RESULTS

The baseline characteristics in both groups were similar except for lower 10 min Apgar scores (p=0.02) in the cooled babies. Despite this, the mean (SD) thalamic NAA/Cr (1.4 (0.1) vs 1.6 (0.2); p<0.001) and NAA/Cho (0.67 (0.08) vs 0.89 (0.11); p<0.001) ratios from MRS were significantly higher in the cooled group. Cooled babies had lower white matter injury scores than non-cooled babies (p=0.02). Four (27%) non-cooled babies with mild HIE developed seizures after 6 hours of age, while none of the cooled babies developed seizures (p=0.008). Neurodevelopmental outcomes at 2 years were available in 40 (85%) of the babies. Adverse outcomes were seen in 2 (14.3%) non-cooled babies, and none of the cooled babies (p=0.09).

CONCLUSIONS

Therapeutic hypothermia may have a neuroprotective effect in babies with mild HIE, as demonstrated by improved MRS biomarkers and reduced white matter injury on MRI. This may warrant further evaluation in adequately powered randomised controlled trials.

Early identification of neonatal mild hypoxic-ischemic encephalopathy by amide proton transfer magnetic resonance imaging: A pilot study

PURPOSE

This study aimed to evaluate the amide proton transfer (APT) values in neonates with mild hypoxic-ischemic encephalopathy (HIE) using APT imaging.

METHOD

A total of 30 full-term neonates with mild HIE (16 males and 14 females; mean postnatal age 4.2 days, age range 2-7 days) and 12 normal neonates (six males and six females; mean postnatal age 3.3 days, age range 2-5 days) underwent conventional magnetic resonance imaging and APT imaging. APT measurements were performed in multiple regions of interest (ROIs) in the brain. APT values were statistically analyzed to assess for significant differences between the mild HIE and normal neonates in different regions of the brain, and correlation with neonatal gestational age.

RESULTS

In 30 neonates with mild HIE, 10% (3/30) of the HIE patients had normal conventional MRI. There were significant differences in APT values of the HIE group in bilateral caudate, bilateral thalamus, bilateral centrum semiovale and left globus pallidus/putamen (p < 0.05), and no statistical difference was observed in right globus pallidus/putamen (p = 0.051) and brainstem (p = 0.073) between the two groups. Furthermore, APT values in bilateral caudate, bilateral globus pallidus/putamen, bilateral thalamus, and brainstem regions (p < 0.05) exhibited positive linear correlations with gestational age in the control group, except for bilateral centrum semiovale (right: Pearson's r = 0.554, p = 0.062; left: Pearson's r = 0.561, p = 0.058). In the mild HIE groups, no significant correlation with gestational age was found in all regions.

CONCLUSIONS

APT imaging is a feasible and useful technique with diagnostic capability for neonatal HIE.

Update on the current management of newborns with neonatal encephalopathy

Hypoxic-ischemic encephalopathy is a subtype of neonatal encephalopathy and a major contributor to global neonatal morbidity and mortality. Despite advances in obstetric and neonatal care there are still challenges in accurate determination of etiology of neonatal encephalopathy. Thus, identification of intrapartum risk factors and comprehensive evaluation of the neonate is important to determine the etiology and severity of neonatal encephalopathy. In developed countries, therapeutic hypothermia as a standard of care therapy for neonates with hypoxic-ischemic encephalopathy has proven to decrease incidence of death and neurodevelopmental disabilities, including cerebral palsy in surviving children. Advances in neuroimaging, brain monitoring modalities, and biomarkers of brain injury have improved the ability to diagnose, monitor, and treat newborns with encephalopathy. However, challenges remain in early identification of neonates at risk for hypoxic-ischemic brain injury, and determination of the timing and extent of brain injury. Using imaging studies such as Neonatal MRI and MR spectroscopy have proven to be most useful in predicting outcomes in infants with encephalopathy within the first week of life, although comprehensive neurodevelopmental assessments still remains the gold standard for determining long term outcomes. Future studies are needed to identify other newborns with encephalopathy that might benefit from therapeutic hypothermia and to determine the efficacy of other adjunctive neuroprotective strategies. This review focuses on newer evidence and advances in diagnoses and management of infants with neonatal encephalopathy, including novel therapies, as well as prognostication of outcomes to childhood.

The Role of Diffusion Tensor Imaging in Detecting Hippocampal Injury Following Neonatal Hypoxic-Ischemic Encephalopathy

BACKGROUND AND PURPOSE

Neonatal hypoxic-ischemic injury of the brain and resultant encephalopathy (HIE) leads to major developmental impairments by school age. Conventional/anatomical MRI often fails to detect hippocampal injury in mild cases. We hypothesize that diffusion tensor imaging (DTI) has greater sensitivity for identifying subtle hippocampal injury.

METHODS

We retrospectively analyzed DTI data collected from a cohort of neonates with HIE and controls. Conventional MRI sequences were classified qualitatively according to severity using a modified Barkovich scale. Using multivariate linear regression, we compared hippocampal DTI scalars of HIE patients and controls. Spearman correlation was used to test the association of DTI scalars in the hippocampal and thalamic regions. A multiple regression analysis tested the association of the DTI scalars with short-term outcomes.

RESULTS

Fifty-five neonates with HIE (42% males) and 13 controls (54% males) were included. Hippocampal DTI scalars were similar between HIE and control groups, even when restricting the HIE group to those with moderate-to-severe injury (8 subjects). DTI scalars of the thalamus were significantly lower in the moderate-to-severely affected patients compared to controls (right fractional anisotropy [FA] .148 vs. .182, P = .01; left FA .147 vs. .181, P = .03). Hippocampal and thalamic DTI scalars were correlated (P < .001). Hippocampal DTI scalars were not associated with short-term outcomes.

CONCLUSIONS

Quantitative DTI analysis of the hippocampus in neonates following HIE is a feasible technique to examine neuronal injury. Although DTI scalars were useful in identifying thalamic injury in our cohort, hippocampal DTI analysis did not provide additional information regarding hippocampal injury following HIE.

MRI as a biomarker for mild neonatal encephalopathy

Historically, there has been limited neuro-imaging data acquired on infants with mild neonatal encephalopathy (NE). This likely reflects the traditional assumption that these infants had a universally good prognosis. As new evidence has emerged challenging this assumption, there has been a renewed interest in the neuro-imaging findings of these infants. To date, magnetic resonance imaging (MRI) studies in infants with mild NE have demonstrated abnormalities in 20-40% of cases suggestive that the injury occurs during the peripartum period with a predominant watershed pattern of injury. The severity of the injury on MRI in infants with mild NE varies, but includes patterns of injury that have been associated with long-term neuro-developmental impairment.

Relevance of urinary S100B protein levels as a short-term prognostic biomarker in asphyxiated infants treated with hypothermia

The initial diagnosis of neonatal hypoxic-ischemic encephalopathy is based on nervous system clinical manifestations. The use of biomarkers to monitor brain injury and evaluate neuroprotective effects allows early intervention and treatment. This study was designed to determine the short-term prognostic significance of urinary S100B calcium-binding protein (S100B) in asphyxiated newborns treated with hypothermia.An observational prospective study was conducted over a period of 5 years in 31 newborns with hypoxic-ischemic encephalopathy who received therapeutic hypothermia. The patients were divided into 2 groups: Group A (13 newborns with a normal neurological examination before discharge) and Group B (18 newborns who died during admission or had an abnormal neurologic examination before discharge). Urinary S100B was the main variable, serum S100B and neuron-specific enolase (NSE) were considered as secondary variables, and all of them were assessed on the first 3 days of life. The newborns were subsequently divided into groups with normal and abnormal electrophysiological and imaging findings.Mean urinary S100B levels were significantly higher in group B than group A on day 1 (10.58 ± 14.82 vs 4.65 ± 9.16 μg/L, P = .031) and day 2 (5.16 ± 7.63 vs 0.88 ± 2.53, P = .002). The optimal cutoff for urinary S100B on day 1 was >1.11 μg/L of (sensitivity, 100%; specificity 60%) for the prediction of neonatal death and < 0.66 μg/L (sensitivity 83% and specificity 70%) for the prediction of a normal neurological examination before discharge. It was not possible to calculate cutoffs with a similar accuracy for serum S100B or NSE. Urinary S100B on day 1 was higher in patients with abnormal magnetic resonance imaging findings (7.89 ± 8.09 vs 4.49 ± 9.14, P = .039) and abnormal positron emission tomography findings (8.60 ± 9.29 vs 4.30 ± 8.28, P = .038). There were no significant differences in S100B levels between patients with normal and abnormal electroencephalography results.Urinary S100B measured in the first days of life can predict neonatal death and short-term prognosis in asphyxiated newborns treated with hypothermia. The method is convenient, noninvasive, and has a higher sensitivity and specificity than measurement of serum S100B or NSE.

Neurosonography: Assessing the Premature Infant

Neurosonography has proven to be helpful in neonatal brain diagnosis. Premature infants are at great risk for intraventricular hemorrhage and periventricular leukomalacia, key abnormalities affecting developmental outcome. Here we discuss technique, anatomy, variants and key points for diagnosis.

Transient receptor potential melastatin 2 channels (TRPM2) mediate neonatal hypoxic-ischemic brain injury in mice

Transient receptor potential melastatin 2 (TRPM2), a calcium-permeable non-selective cation channel, is reported to mediate brain damage following ischemic insults in adult mice. However, the role of TRPM2 channels in neonatal hypoxic-ischemic brain injury remains unknown. We hypothesize that TRPM2^+/- and TRPM2^-/- neonatal mice have reduced hypoxic-ischemic brain injury. To study the effect of TRPM2 on neonatal brain damage, we used 2,3,5-triphenyltetrazolium chloride (TTC) staining to assess the infarct volume and whole brain imaging to assess morphological changes in the brain. In addition, we also evaluated neurobehavioral outcomes for sensorimotor function 7days following hypoxic-ischemic brain injury. We report that the infarct volumes were significantly smaller and behavioral outcomes were improved in both TRPM2^+/- and TRPM2^-/- mice compared to that of wildtype mice. Next, we found that TRPM2-null mice showed reduced dephosphorylation of GSK-3β following hypoxic ischemic injury unlike sham mice. TRPM2^+/- and TRPM2^-/- mice also had reduced activation of astrocytes and microglia in ipsilateral hemispheres, compared to wildtype mice. These findings suggest that TRPM2 channels play an essential role in mediating hypoxic-ischemic brain injury in neonatal mice. Genetically eliminating TRPM2 channels can provide neuroprotection against hypoxic-ischemic brain injury and this effect is elicited in part through regulation of GSK-3β.

Growth of Thalamocortical Fibers to the Somatosensory Cortex in the Human Fetal Brain

Thalamocortical (TH-C) fiber growth begins during the embryonic period and is completed by the third trimester of gestation in humans. Here we determined the timing and trajectories of somatosensory TH-C fibers in the developing human brain. We analyzed the periods of TH-C fiber outgrowth, path-finding, "waiting" in the subplate (SP), target selection, and ingrowth in the cortical plate (CP) using histological sections from post-mortem fetal brain [from 7 to 34 postconceptional weeks (PCW)] that were processed with acetylcholinesterase (AChE) histochemistry and immunohistochemical methods. Images were compared with post mortem diffusion tensor imaging (DTI)-based fiber tractography (code No NO1-HD-4-3368). The results showed TH-C axon outgrowth occurs as early as 7.5 PCW in the ventrolateral part of the thalamic anlage. Between 8 and 9.5 PCW, TH-C axons form massive bundles that traverse the diencephalic-telencephalic boundary. From 9.5 to 11 PCW, thalamocortical axons pass the periventricular area at the pallial-subpallial boundary and enter intermediate zone in radiating fashion. Between 12 and 14 PCW, the TH-C axons, aligned along the fibers from the basal forebrain, continue to grow for a short distance within the deep intermediate zone and enter the deep CP, parallel with SP expansion. Between 14 and 18 PCW, the TH-C interdigitate with callosal fibers, running shortly in the sagittal stratum and spreading through the deep SP ("waiting" phase). From 19 to 22 PCW, TH-C axons accumulate in the superficial SP below the somatosensory cortical area; this occurs 2 weeks earlier than in the frontal and occipital cortices. Between 23 and 24 PCW, AChE-reactive TH-C axons penetrate the CP concomitantly with its initial lamination. Between 25 and 34 PCW, AChE reactivity of the CP exhibits an uneven pattern suggestive of vertical banding, showing a basic 6-layer pattern. In conclusion, human thalamocortical axons show prolonged growth (4 months), and somatosensory fibers precede the ingrowth of fibers destined for frontal and occipital areas. The major features of growing TH-C somatosensory fiber trajectories are fan-like radiation, short runs in the sagittal strata, and interdigitation with the callosal system. These results support our hypothesis that TH-C axons are early factors in SP and CP morphogenesis and synaptogenesis and may regulate cortical somatosensory system maturation.

Focal Brain Injury Associated with a Model of Severe Hypoxic-Ischemic Encephalopathy in Nonhuman Primates

Worldwide, hypoxic-ischemic encephalopathy (HIE) is a major cause of neonatal mortality and morbidity. To better understand the mechanisms contributing to brain injury and improve outcomes in neonates with HIE, better preclinical animal models that mimic the clinical situation following birth asphyxia in term newborns are needed. In an effort to achieve this goal, we modified our nonhuman primate model of HIE induced by in utero umbilical cord occlusion (UCO) to include postnatal hypoxic episodes, in order to simulate apneic events in human neonates with HIE. We describe a cohort of 4 near-term fetal Macaca nemestrina that underwent 18 min of in utero UCO, followed by cesarean section delivery, resuscitation, and subsequent postnatal mechanical ventilation, with exposure to intermittent daily hypoxia (3 min, 8% O2 3-8 times daily for 3 days). After delivery, all animals demonstrated severe metabolic acidosis (pH 7 ± 0.12; mean ± SD) and low APGAR scores (<5 at 10 min of age). Three of 4 animals had both electrographic and clinical seizures. Serial blood samples were collected and plasma metabolites were determined by 2-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOFMS). The 4 UCO animals and a single nonasphyxiated animal (delivered by cesarean section but without exposure to UCO or prolonged sedation) underwent brain magnetic resonance imaging (MRI) on day 8 of life. Thalamic injury was present on MRI in 3 UCO animals, but not in the control animal. Following necropsy on day 8, brain histopathology revealed neuronal injury/loss and gliosis in portions of the ventrolateral thalamus in all 4 UCO, with 2 animals also demonstrating putamen/globus pallidus involvement. In addition, all 4 UCO animals demonstrated brain stem gliosis, with neuronal loss present in the midbrain, pons, and lateral medulla in 3 of 4 animals. Transmission electron microscopy imaging of the brain tissues was performed, which demonstrated ultrastructural white matter abnormalities, characterized by perinuclear vacuolation and axonal dilation, in 3 of 4 animals. Immunolabeling of Nogo-A, a negative regulator of neuronal growth, was not increased in the injured brains compared to 2 control animals. Using GC × GC-TOFMS, we identified metabolites previously recognized as potential biomarkers of perinatal asphyxia. The basal ganglia-thalamus-brain stem injury produced by UCO is consistent with the deep nuclear/brainstem injury pattern seen in human neonates after severe, abrupt hypoxic-ischemic insults. The UCO model permits timely detection of biomarkers associated with specific patterns of neonatal brain injury, and it may ultimately be useful for validating therapeutic strategies to treat neonatal HIE.

Neurologic Correlates of Gait Abnormalities in Cerebral Palsy: Implications for Treatment

Cerebral palsy (CP) is the most common movement disorder in children. A diagnosis of CP is often made based on abnormal muscle tone or posture, a delay in reaching motor milestones, or the presence of gait abnormalities in young children. Neuroimaging of high-risk neonates and of children diagnosed with CP have identified patterns of neurologic injury associated with CP, however, the neural underpinnings of common gait abnormalities remain largely uncharacterized. Here, we review the nature of the brain injury in CP, as well as the neuromuscular deficits and subsequent gait abnormalities common among children with CP. We first discuss brain injury in terms of mechanism, pattern, and time of injury during the prenatal, perinatal, or postnatal period in preterm and term-born children. Second, we outline neuromuscular deficits of CP with a focus on spastic CP, characterized by muscle weakness, shortened muscle-tendon unit, spasticity, and impaired selective motor control, on both a microscopic and functional level. Third, we examine the influence of neuromuscular deficits on gait abnormalities in CP, while considering emerging information on neural correlates of gait abnormalities and the implications for strategic treatment. This review of the neural basis of gait abnormalities in CP discusses what is known about links between the location and extent of brain injury and the type and severity of CP, in relation to the associated neuromuscular deficits, and subsequent gait abnormalities. Targeted treatment opportunities are identified that may improve functional outcomes for children with CP. By providing this context on the neural basis of gait abnormalities in CP, we hope to highlight areas of further research that can reduce the long-term, debilitating effects of CP.

Impaired Gas Exchange at Birth and Risk of Intellectual Disability and Autism: A Meta-analysis

We conducted meta-analyses of 67 studies on the association between neonatal proxies of impaired gas exchange and intellectual disability (ID) or autism spectrum disorders (ASD). Neonatal acidosis was associated with an odds ratio (OR) of 3.55 [95 % confidence interval (95 % CI) 2.23-5.49] for ID and an OR of 1.10 (95 % CI 0.91-1.31) for ASD. Children with a 5-min Apgar score of <7 had an OR of 5.39 (95 % CI 3.84-7.55) for ID and an OR of 1.67 (95 % CI 1.34-2.09) for ASD. O2 treatment was associated with an OR of 4.32 (95 % CI 3.23-5.78) for ID and an OR of 2.02 (95 % CI 1.45 to 2.83) for ASD. Our meta-analysis demonstrates an increased risk of ID and (to a lesser extent) ASD in children with neonatal hypoxia. Moreover, our findings raise the possibility that concomitant ID might account for the observed association between the gas exchange proxies and ASD.

Hippocampal and diencephalic pathology in developmental amnesia

Developmental amnesia (DA) is a selective episodic memory disorder associated with hypoxia-induced bilateral hippocampal atrophy of early onset. Despite the systemic impact of hypoxia-ischaemia, the resulting brain damage was previously reported to be largely limited to the hippocampus. However, the thalamus and the mammillary bodies are parts of the hippocampal-diencephalic network and are therefore also at risk of injury following hypoxic-ischaemic events. Here, we report a neuroimaging investigation of diencephalic damage in a group of 18 patients with DA (age range 11-35 years), and an equal number of controls. Importantly, we uncovered a marked degree of atrophy in the mammillary bodies in two thirds of our patients. In addition, as a group, patients had mildly reduced thalamic volumes. The size of the anterior-mid thalamic (AMT) segment was correlated with patients' visual memory performance. Thus, in addition to the hippocampus, the diencephalic structures also appear to play a role in the patients' memory deficit.

Early identification of hypoxic-ischemic encephalopathy by combination of magnetic resonance (MR) imaging and proton MR spectroscopy

Brain damage following a perinatal hypoxic-ischemic encephalopathy (HIE) can be diagnosed by different techniques. The aim of the present study was to combine magnetic resonance (MR) imaging with proton MR spectroscopy in HIE diagnosis and to evaluate their correlation with outcome. A prospective observational cohort study was performed between February 2012 and February 2013. Consecutive newborns, 24 full-term neonates with HIE (mild to moderate and severe group) and 5 normal neonates, were included. Two sequential MR studies were performed; a conventional MR imaging for observation in T1 weighted image (WI) and T2WI, and proton MR spectroscopy for observation in the left or right basal ganglia and thalamus. MR images were assessed and scored by two neuroradiologists who were blinded to the clinical condition of the infants. The mild to moderate group (n=13) and severe group (n=11) were similar in the visualization of punctate hyperintensity lesions on T1WI and brain edema on T2WI. The differences of N-acetylaspartate/creatine (Cr), choline/Cr and lactate/Cr in the basal ganglia and thalamus in the HIE group were significantly different (P<0.05) compared with the control group, while no significant difference was identified between the mild to moderate and severe group (P>0.05). In conclusion, MR spectroscopy is a complementary tool for the diagnosis of HIE.

Neuroimaging and Other Neurodiagnostic Tests in Neonatal Encephalopathy

Hypoxic-ischemic encephalopathy is associated with a high risk of morbidity and mortality in the neonatal period. Long-term neurodevelopmental disability is also frequent in survivors. Conventional MRI defines typical patterns of injury that reflect specific pathophysiologic mechanisms. Advanced magnetic resonance techniques now provide unique perspectives on neonatal brain metabolism, microstructure, and connectivity. The application of these imaging techniques has revealed that brain injury commonly occurs at or near the time of birth and evolves over the first weeks of life. Amplitude-integrated electroencephalogram and near-infrared spectroscopy are increasingly used as bedside tools in neonatal intensive care units to monitor brain function.

Pathophysiology of Birth Asphyxia

The pathophysiology of asphyxia generally results from interruption of placental blood flow with resultant fetal hypoxia, hypercarbia, and acidosis. Circulatory and noncirculatory adaptive mechanisms exist that allow the fetus to cope with asphyxia and preserve vital organ function. With severe and/or prolonged insults, these compensatory mechanisms fail, resulting in hypoxic ischemic injury, leading to cell death via necrosis and apoptosis. Permanent brain injury is the most severe long-term consequence of perinatal asphyxia. The severity and location of injury is influenced by the mechanisms of injury, including degree and duration, as well as the developmental maturity of the brain.

Long-term outcome in a case of shaken baby syndrome

Shaken baby syndrome is one of the most common causes of disability and death in infants younger than one year of age. The syndrome is the result of major mechanical forces affecting the head and central nervous system. The outcome for surviving children is often poor, with both physical and mental disabilities. Multicystic encephalomalacia has been reported as a finding after such shaking. The present case involves a one-month-old boy who was brought to hospital by his father because of somnolence and feeding aversion. Radiological imaging revealed subdural haematomas, and fundoscopy found retinal haemorrhages. During police interrogation, the father confessed to having shaken the infant. Cranial ultrasonography subsequently showed increasing damage of the brain; the boy's general condition worsened. Eight weeks after admission, he died due to renal insufficiency. Upon autopsy, the brain was atrophic, with massive pseudocystic changes of the parenchyma. The case presented impressively shows the possible serious outcome of an admitted incident of shaking and emphasises the importance of an accurate education of parents about its severe and possible lethal consequences.

Plasticity in the Neonatal Brain following Hypoxic-Ischaemic Injury

Hypoxic-ischaemic damage to the developing brain is a leading cause of child death, with high mortality and morbidity, including cerebral palsy, epilepsy, and cognitive disabilities. The developmental stage of the brain and the severity of the insult influence the selective regional vulnerability and the subsequent clinical manifestations. The increased susceptibility to hypoxia-ischaemia (HI) of periventricular white matter in preterm infants predisposes the immature brain to motor, cognitive, and sensory deficits, with cognitive impairment associated with earlier gestational age. In term infants HI causes selective damage to sensorimotor cortex, basal ganglia, thalamus, and brain stem. Even though the immature brain is more malleable to external stimuli compared to the adult one, a hypoxic-ischaemic event to the neonate interrupts the shaping of central motor pathways and can affect normal developmental plasticity through altering neurotransmission, changes in cellular signalling, neural connectivity and function, wrong targeted innervation, and interruption of developmental apoptosis. Models of neonatal HI demonstrate three morphologically different types of cell death, that is, apoptosis, necrosis, and autophagy, which crosstalk and can exist as a continuum in the same cell. In the present review we discuss the mechanisms of HI injury to the immature brain and the way they affect plasticity.

Distinctive sleep problems in children with perinatal moderate or mild hypoxic-ischemia

Extensive studies focus on the cognitive and motor impairments after perinatal hypoxic-ischemia (HI). Sleep problems, although reported to be associated with cerebral palsy (CP), are often overlooked in non-severe HI patients. Here, by investigating the sleep qualities of children with different degrees of HI, we discovered that sleep initiation and maintenance, sleep-related breathing problems, or circadian rhythmic issues were highly associated with children of moderate or mild HI, respectively. Follow-up MRI studies in 2-year old patients showed that periventricular white matter lesions including periventricular leukomalacia (PVL) were prevalent in moderate, but not mild, HI children. In contrast, the occurrence of pineal cysts had a high risk in children with mild HI. Our study provides novel insights into the mechanisms of distinctive sleep problems associated with children of different degrees of HI, and therefore sheds light on the studies of targeted therapeutic treatments for sleep disorders in children who suffer from HI.

Grey matter injury patterns in cerebral palsy: associations between structural involvement on MRI and clinical outcomes

AIMS

In a population cohort of children with grey matter injury (GMI) and cerebral palsy (CP), we aimed to describe and classify magnetic resonance imaging characteristics specific to GMI, and to identify key structure-function associations that serve as a basis for rating GMI in clinically relevant ways.

METHOD

Symmetry, extent of cerebral injury, and pathological pattern for 54 children (37 males, 17 females) with CP and a predominant GMI pattern on chronic-phase magnetic resonance imaging were related to gross motor function, motor type and topography, epilepsy, intellectual disability, blindness, and deafness.

RESULTS

Relative to mild GMI where there was no pallidal abnormality, severe GMI, comprising pallidal abnormality alone or in conjunction with other deep nuclear and generalized cortical-subcortical involvement, was strongly associated with Gross Motor Function Classification System levels IV to V (OR 35.7 [95% CI 3.5, 368.8]). Involvement of the basal ganglia was associated with non-spastic/mixed motor types, but predominantly where cortical-subcortical grey and white matter involvement was not extensive. The prevalence of epilepsy was highest where there was diffuse cortical-subcortical involvement and white matter loss.

INTERPRETATION

Better understanding of structure-function relationships in CP and GMI, and how to rate the severity of GMI, will be helpful in the clinical context and also as a basis for investigation of causal pathways in CP.