Developmental anatomy of the thalamus, perinatal lesions, and neurological development.

The thalamic nuclei develop before a viable preterm age. GABAergic neuronal migration is especially active in the third trimester. Thalamic axons meet cortical axons during subplate activation and create the definitive cortical plate in the second and third trimesters. Default higher-order cortical driver connections to the thalamus are then replaced by the maturing sensory networks, in a process that is driven by first-order thalamic neurons. Surface electroencephalographic activity, generated first in the subplate and later in the cortical plate, gradually show oscillations based on the interaction of the cortex with thalamus, which is controlled by the thalamic reticular nucleus. In viable newborn infants, in addition to sensorimotor networks, the thalamus already contributes to visual, auditory, and pain processing, and to arousal and sleep. Isolated thalamic lesions may present as clinical seizures. In addition to asphyxia and stroke, infection and network injury are also common. Cranial ultrasound can be used to classify neonatal thalamic injuries based on functional parcelling of the mature thalamus. We provide ample illustration and a detailed description of the impact of neonatal focal thalamic injury on neurological development, and discuss the potential for neuroprotection based on thalamocortical plasticity.

Cerebral Doppler imaging in neonates: A guide for clinical application and diagnosis.

Cranial ultrasound reliably diagnoses many neonatal brain disorders. Adding Doppler imaging expands the spectrum by providing information on the status of the vasculature and haemodynamics that may guide further diagnostic and clinical management. Doppler imaging may identify neonates with congenital or acquired vascular abnormalities such as perinatal stroke, sinuvenous thrombosis, vein of Galen malformation, dural sinus malformation, sinus pericranii, and developmental venous anomaly. These entities may need further investigation with complementary imaging modalities such as magnetic resonance imaging and magnetic resonance angiography, or conventional angiography. This review aims to help clinicians to improve their Doppler sonography knowledge and skills in order to use this helpful tool in neonates with neurological symptoms or suspected cerebral vascular abnormalities admitted to the neonatal intensive care unit.

State-of-the-art cranial ultrasound in clinical scenarios for infants born at term and near-term.

Neonates admitted to the intensive care unit are at risk of brain injury. Importantly, infants with signs of neurological impairment need prompt diagnosis to guide intervention. Cranial ultrasound (CUS) is the first-line imaging tool for infants born preterm. New developments in this technology, which now incorporates high-resolution equipment, have notably improved the performance of CUS in infants born at term and near-term. On the other hand, the potential of CUS as a diagnostic tool in older infants is less established. The lack of studies focusing on this topic, local protocol variability among clinical sites, and divergent opinions on CUS patterns of disease entities are the main constraints. This review provides an overview of state-of-the-art CUS as a decision-making tool under different clinical scenarios, such as neonatal encephalopathy, seizures, and suspected central nervous system infection. The CUS features that characterize several patterns supporting a diagnosis are detailed, focusing on haemorrhage and infection.

The Impact of Intraventricular Hemorrhage and Periventricular Leukomalacia on Mortality and Neurodevelopmental Outcome in Very Preterm and Very Low Birthweight Infants: A Prospective Population-based Cohort Study.

OBJECTIVE: To survey the incidence of intraventricular hemorrhage (IVH) and periventricular leukomalacia (PVL) by gestational age and to report the impact on mortality and neurodevelopmental outcome in very preterm/very low birthweight infants. STUDY DESIGN: This was a population-based cohort study of 1927 very preterm/very low birthweight infants born in 2014-2016 and admitted to Flemish neonatal intensive care units. Infants underwent standard follow-up assessment until 2 years corrected age with the Bayley Scales of Infant and Toddler Development and neurological assessments. RESULTS: No brain lesion was present in 31% of infants born at <26 weeks of gestation and 75.8% in infants born at 29-32 weeks of gestation. The prevalence of low-grade IVH/PVL (grades I and II) was 16.8% and 12.7%, respectively. Low-grade IVH/PVL was not related significantly to an increased likelihood of mortality, motor delay, or cognitive delay, except for PVL grade II, which was associated with a 4-fold increase in developing cerebral palsy (OR, 4.1; 95% CI, 1.2-14.6). High-grade lesions (III-IV) were present in 22.0% of the infants born at <26 weeks of gestational and 3.1% at 29-32 weeks of gestation, and the odds of death were ≥14.0 (IVH: OR, 14.0; 95% CI, 9.0-21.9; PVL: OR, 14.1; 95% CI, 6.6-29.9). PVL grades III-IV showed an increased odds of 17.2 for motor delay and 12.3 for cerebral palsy, but were not found to be associated significantly with cognitive delay (OR, 2.9; 95% CI, 0.5-17.5; P = .24). CONCLUSIONS: Both the prevalence and severity of IVH/PVL decreased significantly with advancing gestational age. More than 75% of all infants with low grades of IVH/PVL showed normal motor and cognitive outcome at 2 years corrected age. High-grade PVL/IVH has become less common and is associated with adverse outcomes.

Susceptibility weighted imaging can be a sensitive sequence to detect brain damage in neonates with kernicterus: a case report.

BACKGROUND: Kernicterus in the acute phase is difficult to diagnose. It depends on a high signal on T1 at the globus pallidum and subthalamic nucleus level. Unfortunately, these areas also show a relatively high signal on T1 in neonates as an expression of early myelination. Therefore, a less myelin-dependent sequence, like SWI, may be more sensitive to detecting damage in the globus pallidum area. CASE PRESENTATION: A term baby developed jaundice on day three following an uncomplicated pregnancy and delivery. Total bilirubin peaked at 542 µmol/L on day four. Phototherapy was started, and an exchange transfusion was performed. ABR showed absent responses on day 10. MRI on day eight demonstrated abnormal high signal globus pallidus on T1w, isointense on T2w, without diffusion restriction, and high signal on SWI at globus pallidal and subthalamus level and phase image at globus pallidal level. These findings were consistent with the challenging diagnosis of kernicterus. On follow-up, the infant presented with sensorineural hearing loss and had a work-up for cochlear implant surgery. At 3 months of age, the follow-up MR shows normalization of the T1 and SWI signals and a high signal on T2. CONCLUSIONS: SWI seems more sensitive to injury than the T1w and lacks the disadvantage of the T1w sequence, where early myelin confers a high signal.

Brain Growth Evaluation Assessed with Transfontanellar (B-GREAT) Ultrasound. Old and New Bedside Markers to Estimate Cerebral Growth in Preterm Infants: a Pilot Study.

OBJECTIVE: We aimed to investigate the feasibility of evaluating overall preterm brain growth using a gathered set of measurements of brain structures in standard cranial ultrasound planes. We called this method of assessment Brain Growth Evaluation Assessed with Transfontanellar ultrasound (B-GREAT). STUDY DESIGN: In this prospective observational cohort study, cranial ultrasound was regularly performed (on day 1, 2, 3, and 7 of life, and then weekly until discharge, and at term) in preterm infants born with gestational age (GA) less than 32 weeks. We evaluated corpus callosum length, corpus callosum-fastigium length, anterior horn width, frontal white matter height, total brain surface, deep grey matter height, hemisphere height, transverse cerebellar diameter in the axial view, and transverse cerebellar diameter coronal view. Measurements obtained were used to develop growth charts for B-GREAT markers as a function of postmenstrual age. Reproducibility of B-GREAT markers was studied. RESULTS: A total of 528 cranial ultrasounds were performed in 80 neonates (median birth GA: 28+5 weeks and interquartile range: 27+3-30+5). The intraclass correlation coefficients for intra-observer and inter-observer analyses showed substantial agreement for all B-GREAT markers. Growth curves for B-GREAT markers were developed. CONCLUSION: B-GREAT is a feasible and reproducible method for bedside monitoring of the growth of the main brain structures in preterm neonates. KEY POINTS: · Overall neonatal brain growth is not routinely monitored using ultrasound.. · Old and new markers were used to build a standardized and non-invasive tool to monitor brain growth.. · All B-GREAT measurements had a good intra-observer and inter-observer agreement..

Cranial ultrasound findings in preterm germinal matrix haemorrhage, sequelae and outcome.

Germinal matrix-intraventricular haemorrhage (GMH-IVH), periventricular haemorrhagic infarction (PHI) and its complication, post-haemorrhagic ventricular dilatation (PHVD), are still common neonatal morbidities in preterm infants that are highly associated with adverse neurodevelopmental outcome. Typical cranial ultrasound (CUS) findings of GMH-IVH, PHI and PHVD, their anatomical substrates and underlying mechanisms are discussed in this paper. Furthermore, we propose a detailed descriptive classification of GMH-IVH and PHI that may improve quality of CUS reporting and prediction of outcome in infants suffering from GMH-IVH/PHI.

Diagnostic and predictive value of Doppler ultrasound for evaluation of the brain circulation in preterm infants: a systematic review.

INTRODUCTION: Very and extremely preterm infants frequently have brain injury-related long-term neurodevelopmental problems. Altered perfusion, for example, seen in the context of a hemodynamically significant patent ductus arteriosus (PDA), has been linked to injury of the immature brain. However, a direct relation with outcome has not been reviewed systematically. METHODS: A systematic review was conducted to provide an overview of the value of different cerebral arterial blood flow parameters assessed by Doppler ultrasound, in relation to brain injury, to predict long-term neurodevelopmental outcome in preterm infants. RESULTS: In total, 23 studies were included. Because of heterogeneity of studies, a meta-analysis of results was not possible. All included studies on resistance index (RI) showed significantly higher values in subjects with a hemodynamically significant PDA. However, absolute differences in RI values were small. Studies using Doppler parameters to predict brain injury and long-term neurodevelopmental outcome were inconsistent. DISCUSSION: There is no clear evidence to support the routine determination of RI or other Doppler parameters in the cerebral arteries to predict brain injury and long-term neurodevelopmental outcome in the preterm infant. However, there is evidence that elevated RI can point to the presence of a hemodynamically significant PDA.

The development and validation of a cerebral ultrasound scoring system for infants with hypoxic-ischaemic encephalopathy.

BACKGROUND: Hypoxic-ischaemic encephalopathy (HIE) is an important cause of morbidity and mortality in neonates. When the gold standard MRI is not feasible, cerebral ultrasound (CUS) might offer an alternative. In this study, the association between a novel CUS scoring system and neurodevelopmental outcome in neonates with HIE was assessed. METHODS: (Near-)term infants with HIE and therapeutic hypothermia, a CUS on day 1 and day 3-7 after birth and available outcome data were retrospectively included in cohort I. CUS findings on day 1 and day 3-7 were related to adverse outcome in univariate and the CUS of day 3-7 also in multivariable logistic regression analyses. The resistance index, the sum of deep grey matter and of white matter involvement were included in multivariable logistic regression analyses. A comparable cohort from another hospital was used for validation (cohort II). RESULTS: Eighty-three infants were included in cohort I and 35 in cohort II. The final CUS scoring system contained the sum of white matter (OR = 2.6, 95% CI 1.5-4.7) and deep grey matter involvement (OR = 2.7, 95% CI 1.7-4.4). The CUS scoring system performed well in cohort I (AUC = 0.90) and II (AUC = 0.89). CONCLUSION: This validated CUS scoring system is associated with neurodevelopmental outcome in neonates with HIE.

Intra-mitochondrial Methylation Deficiency Due to Mutations in SLC25A26.

S-adenosylmethionine (SAM) is the predominant methyl group donor and has a large spectrum of target substrates. As such, it is essential for nearly all biological methylation reactions. SAM is synthesized by methionine adenosyltransferase from methionine and ATP in the cytoplasm and subsequently distributed throughout the different cellular compartments, including mitochondria, where methylation is mostly required for nucleic-acid modifications and respiratory-chain function. We report a syndrome in three families affected by reduced intra-mitochondrial methylation caused by recessive mutations in the gene encoding the only known mitochondrial SAM transporter, SLC25A26. Clinical findings ranged from neonatal mortality resulting from respiratory insufficiency and hydrops to childhood acute episodes of cardiopulmonary failure and slowly progressive muscle weakness. We show that SLC25A26 mutations cause various mitochondrial defects, including those affecting RNA stability, protein modification, mitochondrial translation, and the biosynthesis of CoQ10 and lipoic acid.

Bedside Ultrasound-Guided Percutaneous Needle Aspiration of Intra- and Extra-Axial Intracranial Hemorrhage in Neonates.

Intracranial hemorrhage is an important cause of brain injury in the neonatal population and bedside percutaneous needle aspiration has emerged as an alternative due to the major risks that can be caused by standard neurosurgical decompression. We aimed to assess the effectiveness of this minimally invasive bedside technique and conducted a retrospective analysis of all newborn infants with a large extra-axial hemorrhage associated with a parenchymal hemorrhage causing a midline shift, managed at three academic centers over a 15-year period. Collected data included clinical history, laboratory results, review of all imaging studies performed, and neurodevelopmental follow-up. Eight infants (3 preterm and 5 full-term) presented on day 1 to 2 with seizures (n = 6) and apneas (n = 5), signs of increased intracranial pressure (n = 4), and coning (n = 1). Risk factors were present in six. Cranial ultrasound and computed tomography showed a midline shift in all; two infants showed status epilepticus on amplitude-integrated electroencephalography with complete resolution after the procedure. Between 7 and 34 mL could be aspirated associated with a decrease in the midline shift as seen by ultrasonography performed during the puncture. No complications were seen related to the procedure and none of the infants required further acute neurosurgical intervention. On follow-up, three had mild sequelae, including motor coordination problems (n = 1) and hemianopia (n = 2); none developed cerebral palsy or postneonatal epilepsy. Neonates, presenting with severe symptoms, can be managed successfully using ultrasound-guided needle aspiration and this minimally invasive bedside method should be kept in mind before performing neurosurgical decompression.

Neurodevelopmental outcome in very preterm and very-low-birthweight infants born over the past decade: a meta-analytic review.

AIM: The purpose of this systematic review was to provide an up-to-date global overview of the separate prevalences of motor and cognitive delays and cerebral palsy (CP) in very preterm (VPT) and very-low-birthweight (VLBW) infants. METHOD: A comprehensive search was conducted across four databases. Cohort studies reporting the prevalence of CP and motor or cognitive outcome from 18 months corrected age until 6 years of VPT or VLBW infants born after 2006 were included. Pooled prevalences were calculated with random-effects models. RESULTS: Thirty studies were retained, which included a total of 10 293 infants. The pooled prevalence of cognitive and motor delays, evaluated with developmental tests, was estimated at 16.9% (95% confidence interval [CI] 10.4-26.3) and 20.6% (95% CI 13.9-29.4%) respectively. Mild delays were more frequent than moderate-to-severe delays. Pooled prevalence of CP was estimated to be 6.8% (95% CI 5.5-8.4). Decreasing gestational age and birthweight resulted in higher prevalences. Lower pooled prevalences were found with the Third Edition of the Bayley Scales of Infant Development than with the Second Edition. INTERPRETATION: Even though neonatal intensive care has improved over recent decades, there is still a wide range of neurodevelopmental disabilities resulting from VPT and VLBW births. However, pooled prevalences of CP have diminished over the years. WHAT THIS PAPER ADDS: The Bayley Scales of Infant and Toddler Development, Third Edition reported lower pooled prevalences of motor and cognitive delays than the Second Edition. The pooled prevalence of cerebral palsy in infants born extremely preterm was reduced compared with previous meta-analyses.

Neurodevelopmental outcome after neonatal perforator stroke.

AIM: To assess outcome after neonatal perforator stroke in the largest cohort to date. METHOD: Survivors from a cohort of children diagnosed with neonatal perforator stroke using cranial ultrasound or magnetic resonance imaging were eligible for inclusion. Recovery and Recurrence Questionnaire score, presence of cerebral palsy (CP), and crude outcome were assessed, specifically (1) the ability to walk independently, (2) participation in regular education, and (3) the presence of epilepsy. RESULTS: Thirty-seven patients (20 males, 17 females) aged 3 to 14 years (mean age 8y) were included in the study: 14 with isolated single perforator stroke, four with multiple isolated perforator strokes, and 19 with additional brain injury. Out of 18 children with isolated perforator stroke(s), four had CP, one could not walk independently, and one developed epilepsy. The posterior limb of the internal capsule was involved in four out of 18 patients; three of these patients had CP. Of 19 children with additional brain injury, 11 had CP and three were not able to walk independently. Three out of nine children with concomitant cortical middle cerebral artery stroke developed epilepsy. INTERPRETATION: Perforator stroke patterns can be of use in predicting long-term outcome and for guiding counselling and surveillance. Motor outcome was favourable in children with isolated perforator stroke(s), except when the posterior limb of the internal capsule was involved.

Resistive indices of cerebral arteries in very preterm infants: values throughout stay in the neonatal intensive care unit and impact of patent ductus arteriosus.

BACKGROUND: Little is known about cerebral artery resistive index values in infants born extremely preterm. OBJECTIVE: To report resistive index values in various cerebral arteries in a prospective cohort of preterm infants born at <29 weeks' gestation, and to compare resistive index in these arteries and assess the relationship between resistive index and hemodynamically significant patent ductus arteriosus. MATERIALS AND METHODS: Using Doppler imaging, we obtained resistive index values of internal carotid arteries, basilar artery, anterior cerebral artery, and pial and striatal arteries in the first 3 days of age and weekly thereafter until discharge or death. We analyzed paired observations using the Wilcoxon signed-rank test, between-group comparisons with the Mann-Whitney test. RESULTS: We performed 771 examinations in 235 infants. Resistive indices differed among arteries: vessels with larger diameters showed significantly higher resistive indices. Resistive index in infants without patent ductus arteriosus was lower than that in infants with hemodynamically significant patent ductus arteriosus (median in anterior cerebral artery: 0.75 and 0.82, respectively; P<0.001), though this was not statistically significant in all arteries. There was no difference in pre- and post-ligation resistive indices in infants who underwent patent ductus arteriosus ligation. CONCLUSION: For accurate follow-up and comparison of cerebral artery resistive index, the same artery should be examined on each occasion.

Mutation of the iron-sulfur cluster assembly gene IBA57 causes severe myopathy and encephalopathy.

Two siblings from consanguineous parents died perinatally with a condition characterized by generalized hypotonia, respiratory insufficiency, arthrogryposis, microcephaly, congenital brain malformations and hyperglycinemia. Catalytic activities of the mitochondrial respiratory complexes I and II were deficient in skeletal muscle, a finding suggestive of an inborn error in mitochondrial biogenesis. Homozygosity mapping identified IBA57 located in the largest homozygous region on chromosome 1 as a culprit candidate gene. IBA57 is known to be involved in the biosynthesis of mitochondrial [4Fe-4S] proteins. Sequence analysis of IBA57 revealed the homozygous mutation c.941A > C, p.Gln314Pro. Severely decreased amounts of IBA57 protein were observed in skeletal muscle and cultured skin fibroblasts from the affected subjects. HeLa cells depleted of IBA57 showed biochemical defects resembling the ones found in patient-derived cells, including a decrease in various mitochondrial [4Fe-4S] proteins and in proteins covalently linked to lipoic acid (LA), a cofactor produced by the [4Fe-4S] protein LA synthase. The defects could be complemented by wild-type IBA57 and partially by mutant IBA57. As a result of the mutation, IBA57 protein was excessively degraded, an effect ameliorated by protease inhibitors. Hence, we propose that the mutation leads to partial functional impairment of IBA57, yet the major pathogenic impact is due to its proteolytic degradation below physiologically critical levels. In conclusion, the ensuing lethal complex biochemical phenotype of a novel metabolic syndrome results from multiple Fe/S protein defects caused by a deficiency in the Fe/S cluster assembly protein IBA57.

Brain vein disorders in newborn infants.

The brain veins of infants are in a complex phase of remodelling in the perinatal period. Magnetic resonance venography and susceptibility-weighted imaging, together with high-resolution Doppler ultrasound, have provided new tools to aid study of venous developmental anatomy and disease. This review aims to provide a comprehensive background of vein development and perinatal venous lesions in preterm and term-born infants, and to encourage further research in both the fetus and the newborn infant, with the aim of preventing or mitigating parenchymal injury related to diseases involving veins.

Data quality in diffusion tensor imaging studies of the preterm brain: a systematic review.

BACKGROUND: To study early neurodevelopment in preterm infants, evaluation of brain maturation and injury is increasingly performed using diffusion tensor imaging, for which the reliability of underlying data is paramount. OBJECTIVE: To review the literature to evaluate acquisition and processing methodology in diffusion tensor imaging studies of preterm infants. MATERIALS AND METHODS: We searched the Embase, Medline, Web of Science and Cochrane databases for relevant papers published between 2003 and 2013. The following keywords were included in our search: prematurity, neuroimaging, brain, and diffusion tensor imaging. RESULTS: We found 74 diffusion tensor imaging studies in preterm infants meeting our inclusion criteria. There was wide variation in acquisition and processing methodology, and we found incomplete reporting of these settings. Nineteen studies (26%) reported the use of neonatal hardware. Data quality assessment was not reported in 13 (18%) studies. Artefacts-correction and data-exclusion was not reported in 33 (45%) and 18 (24%) studies, respectively. Tensor estimation algorithms were reported in 56 (76%) studies but were often suboptimal. CONCLUSION: Diffusion tensor imaging acquisition and processing settings are incompletely described in current literature, vary considerably, and frequently do not meet the highest standards.

Risk factors, clinical presentation, and neuroimaging findings of neonatal perforator stroke.

BACKGROUND AND PURPOSE: To date, studies on neonatal stroke have mainly focused on cortical stroke. We have focused on perforator strokes, noncortical strokes in the arterial vascular perforator area. We sought to identify risk factors and evaluate clinical presentation and neuroimaging findings for neonatal perforator stroke, which seems to be under-recognized. METHODS: All infants admitted to our tertiary intensive care unit in ≈12 years, whose perforator stroke was diagnosed with postnatal brain imaging, were enrolled in this study. Demographic, perinatal, and postnatal data were evaluated. RESULTS: Seventy-nine perforator strokes were detected in 55 patients (28 boys), with a median gestational age of 37 1/7 weeks (range 24 1/7 to 42 1/7 weeks, 25 preterm). Perforator stroke was asymptomatic in most patients (58%). Initial diagnosis was predominantly made with cranial ultrasound (80%) in the first week of life (60%). Risk factors for stroke were present in all cases: maternal, fetal, and perinatal. Likely pathogenic mechanisms were prolonged birth asphyxia (16%), hypoxia or hypotension (15%), embolism (15%), infection (15%), acute blood loss (9%), and birth trauma (9%). CONCLUSIONS: Previously described risk factors for developing neonatal main artery stroke are probably also associated with neonatal perforator stroke. Perforator stroke is often asymptomatic, but cranial ultrasound is a reliable diagnostic tool in diagnosing perforator stroke.