Comparison of findings on cranial ultrasound and magnetic resonance imaging in preterm infants

Cranial ultrasound in preterm infants ≤ 32 weeks gestation-novel insights from the use of very high-frequency (18-5 MHz) transducers: a case series

The quality of cranial ultrasound has improved over time, with advancing technology leading to higher resolution, faster image processing, digital display, and back-up. However, some brain lesions may remain difficult to characterize: since higher frequencies result in greater spatial resolution, the use of additional transducers may overcome some of these limitations. The very high-frequency transducers (18-5 MHz) are currently employed for small parts and lung ultrasound. Here we report the first case series comparing the very high-frequency probes (18-5 MHz) with standard micro-convex probes (8-5 MHz) for cranial ultrasound in preterm infants. In this case series, we compared cranial ultrasound images obtained with a micro-convex transducer (8-5 MHz) and those obtained with a very high-frequency (18-5 MHz) linear array transducer in 13 preterm infants ≤ 32 weeks gestation (9 with cerebral abnormalities and 4 with normal findings). Ultrasound examinations using the very high-frequency linear transducer and the standard medium-frequency micro-convex transducer were performed simultaneously. We also compared ultrasound findings with brain MRI images obtained at term corrected age. Ultrasound images obtained with the very high-frequency (18-5 MHz) transducer showed high quality and accuracy. Notably, despite their higher frequency and expected limited penetration capacity, brain size is small enough in preterm infants, so that brain structures are close to the transducer, allowing for complete evaluation.    Conclusion: We propose the routine use of very high-frequency linear probes as a complementary scanning modality for cranial ultrasound in preterm infants ≤ 32 weeks gestation. What is Known: • Brain lesions in preterm infants may remain insufficiently defined through conventional cranial ultrasound scan. • Higher frequency probes  offer better spatial resolution but have a narrower filed of exploration and limited penetration capacity. What is New: • Very high-frequency probes were compared with standard medium-frequency probes for cranial ultrasound in infants  ≤ 32 weeks' gestation. • Thanks to the smaller skull size of preterm infants, the new very high-frequency transducers allowed a complete and accurate evaluation.

Prognostic value of cranial ultrasound findings in infants aged <90 days with bacterial meningitis: a single-centre retrospective cohort study

BACKGROUND

Bacterial meningitis (BM) poses a serious threat to infant health. We assessed cranial ultrasound (CUS) changes in infants with BM as possible predictors of the neurological sequelae of BM.

METHODS

We retrospectively assigned 132 infants diagnosed with BM from 2007 to 2021. Neuroimaging characteristics and cerebral blood flow (CBF) profiles identified using CUS were analysed and compared between the groups during the acute and postacute phases of BM.

RESULTS

Overall, 102 infants with CUS and outcome data were recruited. 37/102 (36.3%) infants with neurological developmental impairments comprised the group with sequelae. Abnormal CUS findings increased the risk of sequelae during the postacute phase compared with the acute phase of BM. Prolonged white matter hyperechogenicity was an independent risk factor for sequelae. The CBF profiles of the group with sequelae showed that anterior cerebral artery resistance and pulsatility indices decreased during the acute phase, whereas the mean flow velocity of the middle cerebral artery significantly increased during the postacute phase. Changes in the CBF profiles did not significantly differ in the group without sequelae.

CONCLUSIONS

Serial CUS can facilitate the prognostic assessment of infants aged <90 days with BM. Prolonged white matter hyperechogenicity, brain volume loss and cerebral perfusion disorders contribute to the risk of sequelae.

Corpus callosum long-term biometry in very preterm children related to cognitive and motor outcomes

BACKGROUND

The corpus callosum (CC) is suggested as an indirect biomarker of white matter volume, which is often affected in preterm birth. However, diagnosing mild white matter injury is challenging.

METHODS

We studied 124 children born preterm (mean age: 8.4 ± 1.1 years), using MRI to assess CC measurements and cognitive/motor outcomes based on the Wechsler Intelligence Scale for Children-V (WPPSI-V) and Movement Assessment Battery for Children-2 (MABC-2).

RESULTS

Children with normal outcomes exhibited greater height (10.2 ± 2.1 mm vs. 9.4 ± 2.3 mm; p = 0.01) and fractional anisotropy at splenium (895[680-1000] vs 860.5[342-1000]) and total CC length (69.1 ± 4.8 mm vs. 67.3 ± 5.1 mm; p = 0.02) compared to those with adverse outcomes. All measured CC areas were smaller in the adverse outcome group. Models incorporating posterior CC measurements demonstrated the highest specificity (83.3% Sp, AUC: 0.65) for predicting neurological outcomes. CC length and splenium height were the only linear measurements associated with manual dexterity and total MABC-2 score while both the latter and genu were related with Full-Scale Intelligence Quotient.

CONCLUSIONS

CC biometry in children born very preterm at school-age is associated with outcomes and exhibits a specific subregion alteration pattern. The posterior CC may serve as an important neurodevelopmental biomarker in very preterm infants.

IMPACT

The corpus callosum has the potential to serve as a reliable and easily measurable biomarker of white matter integrity in very preterm children. Estimating diffuse white matter injury in preterm infants using conventional MRI sequences is not always conclusive. The biometry of the posterior part of the corpus callosum is associated with cognitive and certain motor outcomes at school age in children born very preterm. Length and splenium measurements seem to serve as reliable biomarkers for assessing neurological outcomes in this population.

A Multiplanar Radiomics Model Based on Cranial Ultrasound to Predict the White Matter Injury in Premature Infants and an Analysis of its Correlation With Neurodevelopment

OBJECTIVES

To develop and evaluate a multiplanar radiomics model based on cranial ultrasound (CUS) to predict white matter injury (WMI) in premature infants and explore its correlation with neurodevelopment.

METHODS

We retrospectively reviewed 267 premature infants. The radiomics features were extracted from five standard sections of CUS. The Spearman's correlation coefficient combined with the least absolute shrinkage and selection operator (LASSO) was applied to select features and build radiomics signature, and a multiplanar radiomics model was constructed based on the radiomics signature of five planes. The performance of the model was evaluated using the area under the receiver operating characteristic curve (AUC). Infants with WMI were re-examined by ultrasound at 2 and 4 weeks after birth, and the recovery degree of WMI was evaluated using multiplanar radiomics. The relationship between WMI and the recovery degree and neurodevelopment was analyzed.

RESULTS

The AUC of the multiplanar radiomics in the training and validation sets were 0.94 and 0.91, respectively. The neurodevelopmental function scores in infants with WMI were significantly lower than those in healthy preterm infants and full-term newborns (P < .001). There were statistically significant differences in the neurodevelopmental function scores of infants between the 2- and 4-week lesion disappearance and 4-week lesion persistence (P < .001).

CONCLUSIONS

The multiplanar radiomics model showed a good performance in predicting the WMI of premature infants. It can not only provide objective and accurate results but also dynamically monitor the degree of recovery of WMI to predict the prognosis of premature infants.

What risk factors for Developmental Language Disorder can tell us about the neurobiological mechanisms of language development

Language is a complex multidimensional cognitive system that is connected to many neurocognitive capacities. The development of language is therefore strongly intertwined with the development of these capacities and their neurobiological substrates. Consequently, language problems, for example those of children with Developmental Language Disorder (DLD), are explained by a variety of etiological pathways and each of these pathways will be associated with specific risk factors. In this review, we attempt to link previously described factors that may interfere with language development to putative underlying neurobiological mechanisms of language development, hoping to uncover openings for future therapeutical approaches or interventions that can help children to optimally develop their language skills.

Practical Stepwise Approach to Performing Neonatal Brain MR Imaging in the Research Setting

Magnetic resonance imaging (MRI) is a non-invasive imaging technique that is commonly used for the visualization of newborn infant brains, both for clinical and research purposes. One of the main challenges with scanning newborn infants, particularly when scanning without sedation in a research setting, is movement. Infant movement can affect MR image quality and therewith reliable image assessment and advanced image analysis. Applying a systematic, stepwise approach to MR scanning during the neonatal period, including the use of the feed-and-bundle technique, is effective in reducing infant motion and ensuring high-quality images. We provide recommendations for one such systematic approach, including the step-by-step preparation and infant immobilization, and highlight safety precautions to minimize any potential risks. The recommendations are primarily focused on scanning newborn infants for research purposes but may be used successfully for clinical purposes as well, granted the infant is medically stable. Using the stepwise approach in our local research setting, our success rate of acquiring high-quality, analyzable infant brain MR images during the neonatal period is as high as 91%.

A systematic review of immune-based interventions for perinatal neuroprotection: closing the gap between animal studies and human trials

BACKGROUND

Perinatal infection/inflammation is associated with a high risk for neurological injury and neurodevelopmental impairment after birth. Despite a growing preclinical evidence base, anti-inflammatory interventions have not been established in clinical practice, partly because of the range of potential targets. We therefore systematically reviewed preclinical studies of immunomodulation to improve neurological outcomes in the perinatal brain and assessed their therapeutic potential.

METHODS

We reviewed relevant studies published from January 2012 to July 2023 using PubMed, Medline (OvidSP) and EMBASE databases. Studies were assessed for risk of bias using the SYRCLE risk of bias assessment tool (PROSPERO; registration number CRD42023395690).

RESULTS

Forty preclinical publications using 12 models of perinatal neuroinflammation were identified and divided into 59 individual studies. Twenty-seven anti-inflammatory agents in 19 categories were investigated. Forty-five (76%) of 59 studies reported neuroprotection, from all 19 categories of therapeutics. Notably, 10/10 (100%) studies investigating anti-interleukin (IL)-1 therapies reported improved outcome, whereas half of the studies using corticosteroids (5/10; 50%) reported no improvement or worse outcomes with treatment. Most studies (49/59, 83%) did not control core body temperature (a known potential confounder), and 25 of 59 studies (42%) did not report the sex of subjects. Many studies did not clearly state whether they controlled for potential study bias.

CONCLUSION

Anti-inflammatory therapies are promising candidates for treatment or even prevention of perinatal brain injury. Our analysis highlights key knowledge gaps and opportunities to improve preclinical study design that must be addressed to support clinical translation.

Trends in Outcomes of Major Intracerebral Haemorrhage in a National Cohort of Very Preterm Born Infants in Switzerland

BACKGROUND

Major brain lesions, such as grade 3 intraventricular haemorrhage (G3-IVH) and periventricular haemorrhagic infarction (PVHI) are among the main predictors for poor neurodevelopment in preterm infants. In the last decades advancements in neonatal care have led to a general decrease in adverse outcomes.

AIM

To assess trends of mortality and neurodevelopmental impairment (NDI) in a recent Swiss cohort of very preterm infants with grade 3 intraventricular haemorrhage (G3-IVH) and periventricular haemorrhagic infarction (PVHI).

METHODS

In this retrospective population-based cohort study, rates of mortality, and NDI at 2 years corrected age were reported in infants born at 24-29 weeks gestational age (GA) in Switzerland in 2002-2014, with G3-IVH and/or PVHI.

RESULTS

Out of 4956 eligible infants, 462 (9%) developed G3-IVH (n = 172) or PVHI (n = 290). The average mortality rates for the two pathologies were 33% (56/172) and 60% (175/290), respectively. In 2002-2014, no change in rates of mortality (G3-IVH, p = 0.845; PVHI, p = 0.386) or NDI in survivors (G3-IVH, p = 0.756; PVHI, p = 0.588) were observed, while mean GA decreased (G3-IVH, p = 0.020; PVHI, p = 0.004). Multivariable regression analysis showed a strong association of G3-IVH and PVHI for both mortality and NDI. Death occurred after withdrawal of care in 81% of cases.

CONCLUSION

In 2002-2014, rates of mortality and NDI in very preterm born infants with major brain lesions did not change. The significant decrease in mean GA and changing hospital policies over this time span may factor into the interpretation of these results.

Navigating the Complexities of Intraventricular Hemorrhage in Preterm Infants: An Updated Review

Intraventricular hemorrhage (IVH) is a type of bleeding that occurs in the ventricular cavity of the brain. In this comprehensive study, we provide a summary of the pathogenesis, diagnosis, and treatment of intraventricular hemorrhage in premature infants. Preterm babies are at high risk of developing IVH because their germinal matrix is not fully developed, making their blood vessels more prone to rupture. However, that is not necessarily the case in all preterm babies as the inherent structure of the germinal matrix makes it more susceptible to hemorrhage. Incidences of IVH are discussed based on recent data which states that around 12,000 premature infants in the United States experience IVH each year. Although grades I and II make up the majority of IVH cases and are frequently asymptomatic, IVH remains a significant issue for premature infants in neonatal intensive care facilities worldwide. Grades I and II have been linked to mutations in the type IV procollagen gene, COL4A1, as well as prothrombin G20210A and factor V Leiden mutations. Intraventricular hemorrhage can be detected using brain imaging in the first seven to 14 days following delivery. This review also shines a light on reliable methods for identifying IVH in premature newborns like cranial ultrasound and magnetic resonance imaging along with the treatment of IVH which is primarily supportive and involves the management of intracranial pressure, the correction of coagulation abnormalities, and the prevention of seizures.

Intracranial Imaging of Preterm Infants with Suspected Hypoxic Ischemic Encephalopathy: Comparing MRI and Ultrasound

AIMS

We correlate ultrasound, MRI, and clinical findings in neonates with suspected hypoxic ischemic injury.

BACKGROUND

Recent advances in neuroimaging have led to improved detection of subtle insults associated with neurodevelopmental outcomes, beyond more historically described lesions such as large hemorrhages and hydrocephalus.

OBJECTIVE

In this study, we compare cranial ultrasound to MRI for the evaluation of suspected HIE in preterm infants.

METHODS

147 premature infant patients with paired ultrasound and MRI exams were retrospectively analyzed to compare imaging finding accuracy and clinical value.

RESULT

We confirm that ultrasound is highly sensitive and specific for hydrocephalus, ventricular prominence, and gross structural abnormalities. Ultrasound is not a substitute for MRI in cases of small hemorrhages or white matter injury, however, certain US findings were associated with Apgar score and MRI sequelae of HIE.

CONCLUSION

Choosing between ultrasound and MRI for preterm neonates at risk for intracranial abnormalities based on their strengths can reduce cost and maximize clinical utility. MRI provides a highly sensitive identification of subtle brain injury, yet ultrasound is correlated with the peripartum clinical picture as measured by Apgar score.

Microstructural alterations in association tracts and language abilities in schoolchildren born very preterm and with poor fetal growth

BACKGROUND

Prematurity and perinatal risk factors may influence white matter microstructure. In turn, these maturational changes may influence language development in this high-risk population of children.

OBJECTIVE

To evaluate differences in the microstructure of association tracts between preterm and term children and between preterm children with appropriate growth and those with fetal growth restriction and to study whether the diffusion tensor metrics of these tracts correlate with language abilities in schoolchildren with no severe neurological impairment.

MATERIALS AND METHODS

This study prospectively followed 56 very preterm children (mean gestational age: 28.7 weeks) and 21 age- and gender-matched term children who underwent diffusion tensor imaging at a mean age of 9 years. We used automated probabilistic tractography and measured fractional anisotropy in seven bilateral association tracts known to belong to the white matter language network. Both groups participated in language assessment using five standardised tests at the same age.

RESULTS

Preterm children had lower fractional anisotropy in the right superior longitudinal fasciculus 1 compared to term children (P < 0.05). Preterm children with fetal growth restriction had lower fractional anisotropy in the left inferior longitudinal fasciculus compared to preterm children with appropriate fetal growth (P < 0.05). Fractional anisotropy in three dorsal tracts and in two dorsal and one ventral tract had a positive correlation with language assessments among preterm children and preterm children with fetal growth restriction, respectively (P < 0.05).

CONCLUSION

There were some microstructural differences in language-related tracts between preterm and term children and between preterm children with appropriate and those with restricted fetal growth. Children with better language abilities had a higher fractional anisotropy in distinct white matter tracts.

Biomedical and Psychosocial Determinants of Early Neurodevelopment After Preterm Birth

Prematurity and them related conditions are subject of scientific discussion. From the point of view optimization of postpartum processes, timely assessment of individual biomedical and psychosocial conditions and management of preventive intervention is very important, because of its linkage to issues of preterm infants and their families in long-term perspectives. The goal of the literature review is to bring together existing body of knowledge on biomedical, psychological, and social issues of premature infants related to early neurodevelopment in order to achieve better systemic vision. For this goal scientific articles related to neurological development delay of premature children and the possibilities of their timely identification were processed using electronic scientific search systems. Diagnostic tools to identify at-risk children and early intervention programs discussed in the article, significantly improve the chances of premature child development. In the article Introduced materials are to support: Clinicians to make correct decisions regarding important components of premature infants; Healthcare policy makers to plan targeted programs and activities; Public to better understand prematurity issues, especially in case of prematurely-born family members.

Language Impairment in Children of Mothers with Gestational Diabetes, Preeclampsia, and Preterm Delivery: Current Hypothesis and Potential Underlying Mechanisms : Language Impartment and Pregnancy Complications

Many conditions may impair or delay language development, including socioeconomic status, parent's education, or intrauterine environment. Accordingly, increasing evidence has described that pregnancy complications, including gestational diabetes mellitus (GDM), preeclampsia, and preterm delivery, are associated with the offspring's impaired neurodevelopment. Since language is one of the high brain functions, alterations in this function are another sign of neurodevelopment impairment. How these maternal conditions may generate language impairment has yet to be entirely understood. However, since language development requires adequate structural formation and function/connectivity of the brain, these processes must be affected by alterations in maternal conditions. However, the underlying mechanisms of these structural alterations are largely unknown. This manuscript critically analyzes the literature focused on the risk of developing language impairment in children of mothers with GDM, preeclampsia, and preterm delivery. Furthermore, we highlight potential underlying molecular mechanisms associated with these alterations, such as neuroinflammatory and metabolic and cerebrovascular alterations.

Interobserver reliability between pediatric radiologists and residents in ultrasound evaluation of intraventricular hemorrhage in premature infants

BACKGROUND

Germinal matrix intraventricular hemorrhage (IVH) may contribute to significant morbidity and mortality in premature infants. Timely identification and grading of IVH affect decision-making and clinical outcomes. There is possibility of misinterpretation of the ultrasound appearances, and the interobserver variability has not been investigated between radiology resident and board-certified radiologist.

AIM

To assess interobserver reliability between senior radiology residents performing bedside cranial ultrasound during on-call hours and pediatric radiologists.

METHODS

From June 2018 to June 2020, neonatal cranial ultrasound examinations were performed in neonatal intensive care unit. Ultrasound findings were recorded by the residents performing the ultrasound and the pediatric attending radiologists.

RESULTS

In total, 200 neonates were included in the study, with a mean gestational age of 30.9 wk. Interobserver agreement for higher grade (Grade III & IV) IVH was excellent. There was substantial agreement for lower grade (Grade I & II) IVH.

CONCLUSION

There is strong agreement between radiology residents and pediatric radiologists, which is higher for high grade IVHs.

Imaging of Hypoxic-Ischemic Injury (in the Era of Cooling)

Hypoxic-ischemic injury (HII) is a major worldwide contributor of term neonatal mortality and long-term morbidity. At present, therapeutic hypothermia is the only therapy that has demonstrated efficacy in reducing severe disability or death in infants with moderate to severe encephalopathy. MRI and MRS performed during the first week of life are adequate to assess brain injury and offer prognosis. Patterns of injury will depend on the gestation age of the neonate, as well as the degree of hypotension.

Routine Use of Cerebral Magnetic Resonance Imaging in Infants Born Extremely Preterm

OBJECTIVE

To describe cerebral abnormalities and their risk factors in a contemporary cohort of infants born extremely premature after the introduction of routine cerebral magnetic resonance imaging (cMRI) at term-equivalent age.

STUDY DESIGN

All cMRI examinations performed during November 2017 and November 2020, based on a standardized neonatal cMRI protocol, were included into analysis. Pathologies were retrospectively classified into 3 categories: intraventricular hemorrhage (IVH), white matter disease, and cerebellar injuries.

RESULTS

A total of 198 cMRI examinations were available for analyses; 93 (47%) showed abnormalities, most frequently IVH (n = 65, 33%), followed by cerebellar injuries (n = 41, 21%), and white matter disease (n = 28, 14%). Severe abnormalities were found in 18% of patients (n = 36). Significant clinical risk factors for abnormalities on cMRI were lower Apgar scores, lower umbilical artery and first neonatal pH, asphyxia, blood culture-proven sepsis (especially late-onset), and prolonged need of respiratory support and supplemental oxygen.

CONCLUSIONS

After routine cMRI, without preconfirmed pathology by cranial ultrasonography, low-grade IVH, noncystic white matter disease, and cerebellar injuries were the most frequently found abnormalities. The clinical value and long-term benefit of the detection of these low-grade pathologies have yet to be confirmed.

Achados de ressonância magnética de encéfalo neonatal: correlação com fatores de risco pré-natais e ultrassonografia transfontanelar

Resumo Objetivo: Avaliar alterações encontradas nas ressonâncias magnéticas (RMs) encefálicas neonatais, correlacionando com a ultrassonografia transfontanelar (USTF), e descrever os principais fatores de risco encontrados. Materiais e Métodos: Foram avaliados exames de 51 pacientes que realizaram RM utilizando protocolo neonatal durante internação hospitalar, correlacionando com resultados da USTF prévia, sendo utilizada, para minimizar as chances de viés, a última USTF realizada. Os dados foram obtidos de prontuário médico e as imagens foram revisadas por médico radiologista especialista em neuroimagem. Resultados: A população foi composta majoritariamente de recém-nascidos prematuros extremos (21; 41,2%) e de extremo baixo peso (22; 43,1%). Foram encontradas alterações em 16 (31,4%) das USTFs e em 30 (58,8%) das RMs, sendo a hemorragia da matriz germinativa o achado mais frequente. Os valores preditivos positivo e negativo da USTF em relação à RM foram de 87% e 54%, respectivamente. Conclusão: A USTF mostrou-se importante na distinção entre os graus de hemorragia da matriz germinativa leve e moderada (I e II) dos graus acentuados (III e IV), sendo considerada um bom exame de rastreio e acompanhamento, principalmente em pacientes mais graves e com fatores de risco.

Alterations on magnetic resonance imaging of the neonatal brain: correlations with prenatal risk factors and transfontanellar ultrasound findings

Abstract Objective: To describe the alterations seen on magnetic resonance imaging (MRI) of the brain in newborns, correlating those alterations with the transfontanellar ultrasound (TFUS) findings, and to describe the main risk factors identified. Materials and Methods: We evaluated the examinations of 51 patients who were submitted to brain MRI with a neonatal protocol during hospitalization. We evaluated the MRI findings and correlated them with previous TFUS findings, using the last TFUS performed in order to minimize the risk of bias. Data were obtained from medical records, and the images were reviewed by a radiologist specializing in neuroimaging. Results: Of the 51 patients evaluated, 21 (41.2%) were extremely preterm infants and 22 (43.1%) were extremely-low-birth-weight infants. Alterations were seen on 16 (31.4%) of the TFUS examinations and on 30 (58.8%) of the brain MRI scans, the most common finding being germinal matrix hemorrhage. The positive and negative predictive values of TFUS in relation to MRI were 87% and 54%, respectively. Conclusion: Because TFUS proved to be capable of distinguishing mild and moderate (grade I and II) germinal matrix hemorrhage from the severe forms (grades III and IV), it can be considered a good tool for screening and follow-up, especially in infants with severe disease and risk factors.

Rate of head ultrasound abnormalities at one month in very premature and extremely premature infants with normal initial screening ultrasound

BACKGROUND

Premature infants are at risk for multiple types of intracranial injury with potentially significant long-term neurological impact. The number of screening head ultrasounds needed to detect such injuries remains controversial.

OBJECTIVE

To determine the rate of abnormal findings on routine follow-up head ultrasound (US) performed in infants born at ≤ 32 weeks' gestational age (GA) after initial normal screening US.

MATERIALS AND METHODS

A retrospective study was performed on infants born at ≤ 32 weeks' GA with a head US at 3-5 weeks following a normal US at 3-10 days at a tertiary care pediatric hospital from 2014 to 2020. Exclusion criteria included significant congenital anomalies, such as congenital cardiac defects necessitating surgery, congenital diaphragmatic hernia or spinal dysraphism, and clinical indications for US other than routine screening, such as sepsis, other risk factors for intracranial injury besides prematurity, or clinical neurological abnormalities. Ultrasounds were classified as normal or abnormal based on original radiology reports. Images from initial examinations with abnormal follow-up were reviewed.

RESULTS

Thirty-three (14.2%) of 233 infants had 34 total abnormal findings on follow-up head US after normal initial US. Twenty-seven infants had grade 1 germinal matrix hemorrhage, and four had grade 2 intraventricular hemorrhage. Two had periventricular echogenicity and one had a focus of cerebellar echogenicity that resolved and was determined to be artifactual.

CONCLUSION

When initial screening head ultrasounds in premature infants are normal, follow-up screening ultrasounds are typically also normal. Abnormal findings are usually limited to grade 1 germinal matrix hemorrhage.

A novel magnetic resonance imaging-based scoring system to predict outcome in neonates born preterm with intraventricular haemorrhage

AIM

To create a magnetic resonance imaging (MRI)-based scoring system specific to neonates born preterm with intraventricular haemorrhage (IVH), which could serve as a reliable prognostic indicator for later development and might allow for improved outcome prediction, individually-tailored parental counselling, and clinical decision-making.

METHOD

This retrospective, two-center observational cohort study included 103 infants born preterm with IVH (61 males, 42 females; median gestational age 26wks 6d), born between 2000 and 2016. Term-equivalent MRI was evaluated using a novel scoring system consisting of 11 items. A total MRI score was calculated and correlated with neurodevelopment between 2 years and 3 years of age. Prediction models for outcome were defined.

RESULTS

The proposed MRI scoring system showed high correlation and strong predictive ability with regard to later cognitive and motor outcome. The prediction models were translated into easy-to-use tables, allowing developmental risk assessment.

INTERPRETATION

The proposed MRI-based scoring system was created especially for infants born preterm with IVH and enables a comprehensive assessment of important brain areas as well as potential additional abnormalities commonly associated with IVH. Thus, it better represents the severity of brain damage when compared with the conventional IVH classification. Our scoring system should provide clinicians with valuable information, to optimize parental counselling and clinical decision-making.

Association of Delivery Room and Neonatal Intensive Care Unit Intubation, and Number of Tracheal Intubation Attempts with Death or Severe Neurological Injury among Preterm Infants

OBJECTIVE

The study aimed to assess the association of tracheal intubation (TI) and where it is performed, and the number of TI attempts with death and/or severe neurological injury (SNI) among preterm infants.

STUDY DESIGN

Retrospective cohort study of infants born 23 to 32 weeks, admitted to a single level-3 neonatal intensive care unit (NICU) between 2015 and 2018. Exposures were location of TI (delivery room [DR] vs. NICU) and number of TI attempts (1 vs. >1). Primary outcome was death and/or SNI (intraventricular hemorrhage grade 3-4 and/or periventricular leukomalacia). Multivariable logistic regression analysis was used to assess association between exposures and outcomes and to adjust for confounders.

RESULTS

Rate of death and/or SNI was 2.5% (6/240) among infants never intubated, 12% (13/105) among NICU TI, 32% (31/97) among DR TI, 20% (17/85) among infants with one TI attempt and 23% (27/117) among infants with >1 TI attempt. Overall, median number of TI attempts was 1 (interquartile range [IQR]: 1-2). Compared with no TI, DR TI (adjusted odds ratio [AOR]: 9.04, 95% confidence interval [CI]: 3.21-28.84) and NICU TI (AOR: 3.42, 95% CI: 1.21-10.61) were associated with higher odds of death and/or SNI. The DR TI was associated with higher odds of death and/or SNI compared with NICU TI (AOR: 2.64, 95% CI: 1.17-6.22). The number of intubation attempts (1 vs. >1) was not associated with death and/or SNI (AOR: 0.95, 95% CI: 0.47-2.03).

CONCLUSION

The DR TI is associated with higher odds of death and/or SNI compared with NICU TI, and may help identify higher risk infants. There was no association between the number of TI attempts and death and/or SNI.

KEY POINTS

· Delivery room intubation correlates with morbidity.. · Less than 2 intubation attempts are not associated with IVH.. · Provider training reduces intubation attempts..

Advanced Brain Imaging in Preterm Infants: A Narrative Review of Microstructural and Connectomic Disruption

Preterm birth disrupts the in utero environment, preventing the brain from fully developing, thereby causing later cognitive and behavioral disorders. Such cerebral alteration occurs beneath an anatomical scale, and is therefore undetectable by conventional imagery. Prematurity impairs the microstructure and thus the histological process responsible for the maturation, including the myelination. Cerebral MRI diffusion tensor imaging sequences, based on water’s motion into the brain, allows a representation of this maturation process. Similarly, the brain’s connections become disorganized. The connectome gathers structural and anatomical white matter fibers, as well as functional networks referring to remote brain regions connected one over another. Structural and functional connectivity is illustrated by tractography and functional MRI, respectively. Their organizations consist of core nodes connected by edges. This basic distribution is already established in the fetal brain. It evolves greatly over time but is compromised by prematurity. Finally, cerebral plasticity is nurtured by a lifetime experience at microstructural and macrostructural scales. A preterm birth causes a negative and early disruption, though it can be partly mitigated by positive stimuli based on developmental neonatal care.

Comparison of Papile versus Laterality-Based Al-Abdi System to Predict Neurodevelopmental Impairment in Extreme Preterm Infants after Severe Germinal Matrix Hemorrhage-Intraventricular Hemorrhage: A Retrospective Comparative Observational Study

BACKGROUND AND PURPOSE

The traditional Papile classification system for severe germinal matrix hemorrhage-intraventricular hemorrhage is limited in objectivity and interrater variability for accurate prediction of neurodevelopmental impairment in extremely preterm infants. Many extremely preterm infants with severe germinal matrix hemorrhage-intraventricular hemorrhage are still offered "redirection of care" in spite of the recent evidence suggesting that many of these infants can have normal outcomes. Therefore, it is important to consider the laterality and extent of brain hemisphere involvement while classifying severe germinal matrix hemorrhage-intraventricular hemorrhage to predict neurodevelopmental impairment. The aim of the present study was to compare the Al-Abdi system with the Papile system for their accuracy in predicting neurodevelopmental impairment in extremely preterm infants with severe germinal matrix hemorrhage-intraventricular hemorrhage.

MATERIALS AND METHODS

This is a retrospective study of extremely preterm infants with severe germinal matrix hemorrhage-intraventricular hemorrhage admitted to a tertiary neonatal intensive care unit (2006-2016). Cranial sonograms were independently re-reviewed by 2 radiologists as per the Al-Abdi system. The prognostic statistical indices for both systems to predict neurodevelopmental impairment were calculated.

RESULTS

A total of 91 infants with severe germinal matrix hemorrhage-intraventricular hemorrhage survived, and 83 (median gestational age, 26.3 weeks; and median birth weight, 890 g) completed developmental assessment. The receiver operating characteristic areas under the curve to predict neurodevelopmental impairment by the Papile versus Al-Abdi systems were 0.702 versus 0.723, respectively (P = .474). Corresponding Al-Abdi cutoff scores of 19, 20, 21, and 22 demonstrated increased specificity (76.36%-85.45%) and correct classification (69.88%-72.29%) to predict moderate-to-severe neurodevelopmental impairment.

CONCLUSIONS

The Al-Abdi system is comparable with the Papile system for predicting neurodevelopmental impairment for extremely preterm infants with severe germinal matrix hemorrhage-intraventricular hemorrhage, with higher Al-Abdi scores being more specific. This finding may prove useful for neonatal health care providers and parents in their decision regarding "continuation of care." Future multicentric studies are warranted to ascertain the validity of individual Al-Abdi scores.

Clinical experience with an in-NICU magnetic resonance imaging system

OBJECTIVE

To evaluate the utility of the 1 Tesla (1 T) Embrace (Aspect Imaging) neonatal magnetic resonance imaging (MRI) scanner in a level III NICU.

STUDY DESIGN

Embrace brain MRI findings for 207 infants were reviewed, including 32 scans directly compared within 5 days with imaging on a 3 T Siemens Trio. Clinical MRI scan abnormalities were also compared to cranial ultrasound findings.

RESULT

Of the 207 Embrace brain MRIs, 146 (70.5%) were obtained for clinical indications and 61 (29.5%) were research cases. Abnormal findings were found in 80 scans, most commonly hemorrhage and white matter injury. Notable findings included a stroke, medullary brainstem tumor, and polymicrogyria. In the 1 T versus 3 T comparison cohort, results were discordant in only one infant with punctate foci of susceptibility noted only on the 3 T scan.

CONCLUSION

The Embrace MRI scans detected clinically relevant brain abnormalities and in a subset were clinically comparable to 3 T scans.

Comparative performance of head ultrasound and MRI in detecting preterm brain injury and predicting outcomes: A systematic review

AIM

To systematically review the literature to compare the performance of head ultrasound (HUS) and magnetic resonance imaging (MRI) in their ability to detect brain injury and their predictive value for neurodevelopmental outcomes.

METHODS

This was a systematic review based on literature search in three electronic databases (MEDLINE, EMBASE, Cochrane Library) and additional sources for studies on routine brain injury screening in preterm neonates published during 2000-May 2020. Studies were included if they reported on the comparative performance of HUS and MRI in detecting preterm brain injury and/or their predictive value for neurodevelopmental outcomes. Findings from the included studies underwent narrative synthesis.

RESULTS

Forty-six studies were included. In comparison with HUS, MRI detected more anomalies and provided more details on the severity and the extent of preterm brain injury, particularly for white matter injury and cerebellar haemorrhage. Neonatal neuroimaging predicted outcomes with high negative predictive value but relatively low positive predictive value. The prognostic value of neonatal neuroimaging varied according to several factors including modality and timing of imaging, and tools used for grading brain injury.

CONCLUSION

Compared with HUS, MRI offers a better characterisation of preterm brain injury and may enhance the ability to predict neurodevelopmental outcomes.

Comparing head ultrasounds and susceptibility-weighted imaging for the detection of low-grade hemorrhages in preterm infants

OBJECTIVE

Intraventricular hemorrhage (IVH) is a complication of prematurity. Grades III and IV IVH lead to significant morbidity, but mounting evidence shows low-grade IVH (grades I-II) may be associated with adverse sequelae. Head ultrasounds (HUS) are used to screen infants for IVH but may miss low-grade IVH. Our study compared the results of HUS around 7 days of age to susceptibility-weighted imaging (SWI) obtained at term-corrected age in infants born at <30 wGA.

STUDY DESIGN

Infants <30 weeks gestational age (GA) with an HUS and MRI at admission to UF Health were identified by a retrospective chart review. Images were re-read by a pediatric neuroradiologist.

RESULTS

Ninety-four infants with a mean GA of 25.8 weeks were identified. Of those with normal HUS, 50% had low-grade IVH on the term-corrected MRI.

CONCLUSIONS

HUS are effective for screening for high-grade IVH. SWI is more sensitive in identifying low-grade IVH.

Neuroimaging at Term Equivalent Age: Is There Value for the Preterm Infant? A Narrative Summary

Advances in neuroimaging of the preterm infant have enhanced the ability to detect brain injury. This added information has been a blessing and a curse. Neuroimaging, particularly with magnetic resonance imaging, has provided greater insight into the patterns of injury and specific vulnerabilities. It has also provided a better understanding of the microscopic and functional impacts of subtle and significant injuries. While the ability to detect injury is important and irresistible, the evidence for how these injuries link to specific long-term outcomes is less clear. In addition, the impact on parents can be profound. This narrative summary will review the history and current state of brain imaging, focusing on magnetic resonance imaging in the preterm population and the current state of the evidence for how these patterns relate to long-term outcomes.

Superficial anatomy of the neonatal cerebrum - an ultrasonographic roadmap

Neurosonography is an essential imaging modality for assessing the neonatal brain, particularly as a screening tool to evaluate intracranial hemorrhage, hydrocephalus and periventricular leukomalacia. The primary advantages of neurosonography include portability, accessibility and lack of ionizing radiation. Its main limitations are intrinsic operator dependence and the need for an open fontanelle. Neurosonographic imaging acquisition is typically performed by placing a sector transducer over the anterior fontanelle and following sagittal and coronal sweeps. The sensitivity of neurosonography has markedly improved thanks to the adoption of modern imaging equipment, the use of dedicated head probes, and the employment of advanced diagnostic US techniques. These developments have facilitated more descriptive identification of specific cerebral anatomical details, improving understanding of the cerebral anatomy by conventional US. Such knowledge is fundamental for enhanced diagnostic sensitivity and is a key to understanding pathological states. Furthermore, familiarity with normal anatomy is crucial for understanding pathological states. Our primary goal in this review was to supplement these technological developments with a roadmap to the cerebral landscape. We accomplish this by presenting a systematic approach to using routine US for consistent identification of the most crucial cerebral landmarks, reviewing their relationship with adjacent structures, and briefly describing their primary function.

Automated brain MRI metrics in the EPIRMEX cohort of preterm newborns: Correlation with the neurodevelopmental outcome at 2 years

PURPOSE

The purpose of this study was to identify in the EPIRMEX cohort the correlations between MRI brain metrics, including diffuse excessive high signal intensities (DEHSI) obtained with an automated quantitative method and neurodevelopmental outcomes at 2 years.

MATERIALS AND METHODS

A total of 390 very preterm infants (gestational age at birth≤32 weeks) who underwent brain MRI at term equivalent age at 1.5T (n=338) or 3T (n=52) were prospectively included. Using a validated algorithm, automated metrics of the main brain surfaces (cortical and deep gray matter, white matter, cerebrospinal fluid) and DEHSI with three thresholds were obtained. Linear adjust regressions were performed to assess the correlation between brain metrics with the ages and stages questionnaire (ASQ) score at 2 years.

RESULTS

Basal ganglia and thalami, cortex and white matter surfaces positively and significantly correlated with the global ASQ score. For all ASQ sub-domains, basal ganglia and thalami surfaces significantly correlated with the scores. DEHSI was present in 289 premature newborns (74%) without any correlation with the ASQ score. Metrics of DEHSI were greater at 3T than at 1.5T.

CONCLUSION

Brain MRI metrics obtained in our multicentric cohort correlate with the neurodevelopmental outcome at 2 years of age. The quantitative detection of DEHSI is not predictive of adverse outcomes. Our automated algorithm might easily provide useful predictive information in daily practice.

Losing the Beat: Contribution of Purkinje Cell Firing Dysfunction to Disease, and Its Reversal

The cerebellum is a brain structure that is highly interconnected with other brain regions. There are many contributing factors to cerebellar-related brain disease, such as altered afferent input, local connectivity, and/or cerebellar output. Purkinje cells (PC) are the principle cells of the cerebellar cortex, and fire intrinsically; that is, they fire spontaneous action potentials at high frequencies. This review paper focuses on PC intrinsic firing activity, which is altered in multiple neurological diseases, including ataxia, Huntington Disease (HD) and autism spectrum disorder (ASD). Notably, there are several cases where interventions that restore or rescue PC intrinsic activity also improve impaired behavior in these mouse models of disease. These findings suggest that rescuing PC firing deficits themselves may be sufficient to improve impairment in cerebellar-related behavior in disease. We propose that restoring PC intrinsic firing represents a good target for drug development that might be of therapeutic use for several disorders.

Beyond Anesthesia Toxicity: Anesthetic Considerations to Lessen the Risk of Neonatal Neurological Injury

Infants who undergo surgical procedures in the first few months of life are at a higher risk of death or subsequent neurodevelopmental abnormalities. Although the pathogenesis of these outcomes is multifactorial, an understanding of the nature and pathogenesis of brain injury in these infants may assist the anesthesiologist in consideration of their day-to-day practice to minimize such risks. This review will summarize the main types of brain injury in preterm and term infants and their key pathways. In addition, the review will address key potential pathogenic pathways that may be modifiable including intraoperative hypotension, hypocapnia, hyperoxia or hypoxia, hypoglycemia, and hyperthermia. Each of these conditions may increase the risk of perioperative neurological injury, but their long-term ramifications are unclear.

Early preterm infants with abnormal psychomotor neurodevelopmental outcome at age two show alterations in amplitude-integrated electroencephalography signals

INTRODUCTION

Recent studies showed that neurodevelopment in preterm infants can be predicted by using amplitude-integrated electroencephalography (aEEG)-derived parameters. In our previous study we demonstrated that aEEG could be useful in predicting neurodevelopmental outcome in very preterm infants at the corrected age of 2 years.

AIM

The aim of this study was to further evaluate aEEG for predicting neurodevelopmental outcome at the at the corrected age of 2 years in preterm infants.

METHODS

Between July 2010 and June 2016 440 very preterm infants were eligible for the study at Innsbruck Medical University Hospital. The aEEG was evaluated for the Burdjalov score in 306 preterm infants (mean gestational age 29.5 weeks; range: 24.1-31.9 weeks). At the corrected age of 2 years outcome was assessed by the Bayley Scales of Infant and Toddler Development.

RESULTS

The cohort was divided into three subgroups: 248 infants with normal outcome, 40 infants with delayed outcome and 18 infants with abnormal outcome. Burdjalov scores were lower in infants with delayed outcome than in infants with normal outcome and even lower in infants with abnormal outcome. Post-hoc analysis showed significant differences between normal and delayed psychomotor outcome at 18-24 h (5 (3;6) versus 3 (3;5), p = .024), 30-36 h (6 (4;8) versus 4 (4;6), p = .033), 42-48 h (7 (5;8.5) versus 4 (4;7), p = .003), 54-60 h (7 (6;9) versus 5 (4;7), p = .003), 66-72 h (8 (6;9) versus 6.5 (4.25;7.75), p = .027) and week one (8 (7;10) versus 6.5 (5;8), p = .021). Additionally, when comparing normal to abnormal outcome, a significant difference was found at week four (12 (9;12) versus 8 (7;10), p = .024). The Burdjalov score was only predictive for a delayed psychomotor outcome, presenting the highest area under the curve (0.690) at week two of life.

CONCLUSION

We observed differences in aEEG signals and neurodevelopmental outcome at the corrected age of 2 years, especially for psychomotor outcome. The predictive value of the Burdjalov score regarding neurodevelopmental outcome at the corrected age of 2 years in preterm infants was low.

Preterm white matter injury: ultrasound diagnosis and classification

White matter injury (WMI) is the most frequent form of preterm brain injury. Cranial ultrasound (CUS) remains the preferred modality for initial and sequential neuroimaging in preterm infants, and is reliable for the diagnosis of cystic periventricular leukomalacia. Although magnetic resonance imaging is superior to CUS in detecting the diffuse and more subtle forms of WMI that prevail in very premature infants surviving nowadays, recent improvement in the quality of neonatal CUS imaging has broadened the spectrum of preterm white matter abnormalities that can be detected with this technique. We propose a structured CUS assessment of WMI of prematurity that seeks to account for both cystic and non-cystic changes, as well as signs of white matter loss and impaired brain growth and maturation, at or near term equivalent age. This novel assessment system aims to improve disease description in both routine clinical practice and clinical research. Whether this systematic assessment will improve prediction of outcome in preterm infants with WMI still needs to be evaluated in prospective studies.

Assessing therapeutic response non-invasively in a neonatal rat model of acute inflammatory white matter injury using high-field MRI

Perinatal infection and inflammatory episodes in preterm infants are associated with diffuse white matter injury (WMI) and adverse neurological outcomes. Inflammation-induced WMI was previously shown to be linked with later hippocampal atrophy as well as learning and memory impairments in preterm infants. Early evaluation of injury load and therapeutic response with non-invasive tools such as multimodal magnetic resonance imaging (MRI) would greatly improve the search of new therapeutic approaches in preterm infants. Our aim was to evaluate the potential of multimodal MRI to detect the response of interleukin-1 receptor antagonist (IL-1Ra) treatment, known for its neuroprotective properties, during the acute phase of injury on a model of neonatal WMI. Rat pups at postnatal day 3 (P3) received intracerebral injection of lipopolysaccharide with systemic IL-1Ra therapy. 24 h later (P4), rats were imaged with multimodal MRI to assess microstructure by diffusion tensor imaging (DTI) and neurochemical profile of the hippocampus with ¹H-magnetic resonance spectroscopy. Astrocyte and microglial activation, apoptosis and the mRNA expression of pro-inflammatory and necroptotic markers were assessed. During the acute phase of injury, neonatal LPS exposure altered the concentration of hippocampus metabolites related to neuronal integrity, neurotransmission and membrane integrity and induced diffusivity restriction. Just 24 h after initiation of therapy, early indication of IL-1Ra neuroprotective effect could be detected in vivo by non-invasive spectroscopy and DTI, and confirmed with immunohistochemical evaluation and mRNA expression of inflammatory markers and cell death. In conclusion, multimodal MRI, particularly DTI, can detect not only injury but also the acute therapeutic effect of IL-1Ra suggesting that MRI could be a useful non-invasive tool to follow, at early time points, the therapeutic response in preterm infants.

Early Prediction of Periventricular Leukomalacia Using Quantitative Texture Analysis of Serial Cranial Ultrasound Scans in Very Preterm Infants

We compared texture parameters of serial cranial ultrasound (cUS) images of periventricular leukomalacia (PVL) and normal periventricular echogenicity (PVE) in very preterm infants and evaluated the early predictive values of texture analysis (TA) for PVL. Ten individuals with PVL and 10 control individuals with PVE assessed with an initial cUS within 1 wk of birth and follow-up cUS at 2-3 and 4-6 wk of life were included. TA was performed on the region of interest of PVE at the parieto-occipital area on serial cUS. Opposite changes in variance were obtained between the first two cUS sessions in both groups (p = 0.017 in PVL and p = 0.005 in PVE). The variance-to-mean ratio (VMR) between the second and first cUS sessions differed (p = 0.016) and reliably stratified the groups (area under the receiver operating characteristic curve: 0.820, 95% confidence interval: 0.587-1.000, sensitivity: 100%, specificity: 60%). TA of serial cUS helps to predict PVL within 3 wk of life.

Comparison of MRI and neurosonogram 1- and 2-dimensional morphological measurements of the newborn corpus callosum

BACKGROUND

Developmental abnormalities of the corpus callosum (CC) are linked to multiple neuro-developmental disorders, for which neonatal neuroimaging may allow earlier diagnosis and intervention. MRI is often considered the most sensitive imaging modality to white matter changes, while neurosonogram (NS) remains the clinical staple. This study assesses the correlation between MRI and US measurements of the neonatal CC using a protocol derived from established methodologies.

METHODS

MR and NS images from an existing cohort of term infants (≥37 weeks gestational age) were studied. Length and area measurements of the CC made with linear (LUS) and phased array US (PUS) data were compared to those from MRI. Intra-observer reliabilities were estimated.

RESULTS

Moderate-to-strong correlation strengths were observed for length measurements and the total area of the CC. Sectional area measurements showed poorer correlations. Bland-Altman plots support improved correspondence of length and total area measurements. LUS data appeared to correspond closer to MRI. All three modalities showed comparable repeatability.

CONCLUSION

NS correlates well with some MRI measurements of the CC and shows similar levels of repeatability, making them possibly interchangeable. Use of LUS, a technique rarely used for NS, may be preferable to the standard approach for morphological studies.

Comparison of cranial ultrasound and MRI for detecting BRAIN injury in extremely preterm infants and correlation with neurological outcomes at 1 and 3 years

This study aimed to investigate the accuracy of different grades of brain injuries on serial and term equivalent age (TEA)-cranial ultrasound imaging (cUS) as compared to TEA magnetic resonance imaging (MRI) in extremely preterm infants < 28 weeks, and determine the predictive value of imaging abnormalities on neurodevelopmental outcome at 1 and 3 years. Seventy-five infants were included in the study. Severe TEA-cUS injury had high positive predictive value-PPV (100%) for predicting severe MRI injury compared to mild to moderate TEA-cUS injury or severe injury on worst cranial ultrasound scan. Absence of moderate to severe injury on TEA cUS or worst serial cUS was a good predictor of a normal MRI (negative predictive values > 93%). Severe grade 3 injuries on TEA-US had high predictive values in predicting abnormal neurodevelopment at both 1 and 3 years of age (PPV 100%). All grades of MRI and worst serial cUS injuries poorly predicted abnormal neurodevelopment at 1 and 3 years. Absence of an injury either on a cranial ultrasound or an MRI did not predict a normal outcome. Multiple logistic regression did not show a significant correlation between imaging injury and neurodevelopmental outcomes.Conclusion: This study demonstrates that TEA cUS can reliably identify severe brain abnormalities that would be seen on MRI imaging and positively predict abnormal neurodevelopment at both 1 and 3 years. Although MRI can pick up more subtle abnormalities that may be missed on cUS, their predictive value on neurodevelopmental impairment is poor. Normal cUS and MRI scan may not exclude abnormal neurodevelopment. Routine TEA-MRI scan provides limited benefit in predicting abnormal neurodevelopment in extremely preterm infants. What is Known: • Preterm neonates are at increased risk of white matter and other brain injuries, which may be associated with adverse neurodevelopmental outcome. • MRI is the most accurate method in detecting white matter injuries. What is New: • TEA-cUS can reliably detect severe brain injuries on MRI, but not mild/moderate lesions as well as abnormal neurodevelopment at 1 and 3 years. • TEA-MRI brain injury is poor in predicting abnormal neurodevelopment at 1 and 3 years and normal cUS or MRI brain injury may not guarantee normal neurodevelopment.

Quantitative Analysis of Punctate White Matter Lesions in Neonates Using Quantitative Susceptibility Mapping and R2* Relaxation

BACKGROUND AND PURPOSE

It is difficult to distinguish punctate white matter lesions from focal hemorrhagic lesions in neonates on conventional MR imaging because both kinds of lesions show increased signal intensity on T1-weighted images and, frequently, decreased signal intensity on T2-weighted images. Our aim was to distinguish punctate white matter lesions and focal hemorrhagic lesions using quantitative measures.

MATERIALS AND METHODS

In the current study, we acquired multiecho gradient recalled-echo MR imaging data from 24 neonates with hypoxic-ischemic encephalopathy and postprocessed them as R2* relaxation maps and quantitative susceptibility maps. Seven subjects who were found to have multifocal punctate white matter lesions and/or focal hemorrhagic lesions on R2* maps were included (mean gestational age at birth, 33 ± 4.28 weeks; mean gestational age at scanning, 38 ± 2 weeks). Manually drawing ROIs on R2* maps, we measured R2* and magnetic susceptibility values of the lesions, along with white matter regions within the corpus callosum as healthy comparison tissue.

RESULTS

R2* and magnetic susceptibility values were both found to easily distinguish punctate white matter lesions, focal hemorrhagic lesions, and healthy white matter tissue from each other (P < .05), with a large Hedge g. R2* and magnetic susceptibility values were significantly increased in focal hemorrhagic lesions compared with punctate white matter lesions and healthy white matter tissue. Punctate white matter lesions were also found to have significantly increased values over healthy white matter tissue.

CONCLUSIONS

R2* and quantitative susceptibility maps can be used to help clinicians distinguish and measure focal hemorrhages, punctate white matter lesions, and healthy white matter tissue.

Glutamate Transport and Preterm Brain Injury

Preterm birth complications are the leading cause of child death worldwide and a top global health priority. Among the survivors, the risk of life-long disabilities is high, including cerebral palsy and impairment of movement, cognition, and behavior. Understanding the molecular mechanisms of preterm brain injuries is at the core of future healthcare improvements. Glutamate excitotoxicity is a key mechanism in preterm brain injury, whereby the accumulation of extracellular glutamate damages the delicate immature oligodendrocytes and neurons, leading to the typical patterns of injury seen in the periventricular white matter. Glutamate excitotoxicity is thought to be induced by an interaction between environmental triggers of injury in the perinatal period, particularly cerebral hypoxia-ischemia and infection/inflammation, and developmental and genetic vulnerabilities. To avoid extracellular build-up of glutamate, the brain relies on rapid uptake by sodium-dependent glutamate transporters. Astrocytic excitatory amino acid transporter 2 (EAAT2) is responsible for up to 95% of glutamate clearance, and several lines of evidence suggest that it is essential for brain functioning. While in the adult EAAT2 is predominantly expressed by astrocytes, EAAT2 is transiently upregulated in the immature oligodendrocytes and selected neuronal populations during mid-late gestation, at the peak time for preterm brain injury. This developmental upregulation may interact with perinatal hypoxia-ischemia and infection/inflammation and contribute to the selective vulnerability of the immature oligodendrocytes and neurons in the preterm brain. Disruption of EAAT2 may involve not only altered expression but also impaired function with reversal of transport direction. Importantly, elevated EAAT2 levels have been found in the reactive astrocytes and macrophages of human infant post-mortem brains with severe white matter injury (cystic periventricular leukomalacia), potentially suggesting an adaptive mechanism against excitotoxicity. Interestingly, EAAT2 is suppressed in animal models of acute hypoxic-ischemic brain injury at term, pointing to an important and complex role in newborn brain injuries. Enhancement of EAAT2 expression and transport function is gathering attention as a potential therapeutic approach for a variety of adult disorders and awaits exploration in the context of the preterm brain injuries.

A Novel Scoring System for Term-Equivalent-Age Cranial Ultrasound in Extremely Preterm Infants

The role of term-equivalent-age (TEA) cranial ultrasound (cUS) in predicting outcome in preterm infants is increasingly being recognized. However, a detailed quantitative scoring system that allows comparison of groups and comparison with TEA magnetic resonance imaging (MRI) scoring systems is lacking. Eighty-four extremely preterm infants underwent cUS and MRI at TEA. Cranial US was evaluated using a novel detailed scoring system. Agreement between cUS and MRI scores was good (Spearman's ρ = 0.51, p < 0.001). Outcome at 30 mo corrected was assessed in 66 of 84 preterm and 85 term-born infants. Sensitivity was the same for cUS and MRI in prediction of cerebral palsy (75%) and severe cognitive delay (100%); the specificity was slightly higher for MRI (cerebral palsy: 97% vs. 90%, severe cognitive delay: 95% vs. 90%). The proposed novel cUS scoring system is a helpful tool in quantitative assessment of cUS at TEA and prediction of outcome at 30 mo.

Preterm brain injury: Germinal matrix-intraventricular hemorrhage and post-hemorrhagic ventricular dilatation

Germinal matrix hemorrhage and intraventricular hemorrhages (GMH-IVH) remain a common and clinically significant problem in preterm infants, particularly extremely preterm infants. A large GMH-IVH is often complicated by posthemorrhagic ventricular dilation (PHVD) or parenchymal hemorrhagic infarction and is associated with an increased risk of adverse neurologic sequelae. The widespread use of cranial ultrasonography since the early 1980s has shown a gradual decrease in the incidence of GMH-IVH and has helped with the identification of antenatal and perinatal risk factors and timing of the lesion. The increased use of magnetic resonance imaging (MRI) has contributed to more detailed visualization of the site and extent of the GMH-IVH. In addition, MRI has contributed to the awareness of associated white matter changes as well as associated cerebellar hemorrhages. Although GMH-IVH and PHVD still cannot be prevented, cerebrospinal fluid drainage initiated in the early stage of PHVD development seems to be associated with a better neurodevelopmental outcome. Further studies are underway to improve treatment strategies for PHVD and to potentially prevent and repair GMH-IVH and PHVD and associated brain injury. This chapter discusses the pathogenesis, incidence, risk factors, and management, including preventive measures, of GHM-IVH and PHVD.

Brain imaging in preterm infants <32 weeks gestation: a clinical review and algorithm for the use of cranial ultrasound and qualitative brain MRI

The aim is to review the evidence about the utility of term-equivalent age (TEA) magnetic resonance imaging (MRI) in predicting neurodevelopmental outcomes for preterm neonates. Preterm birth accounts for ~12% of all deliveries in the United States and is the leading cause of neurologic disabilities in children. From the neonatologist perspective, it is critically important to identify preterm infants at risk of subsequent neurodevelopmental disability who may benefit from early intervention services. However "the choose wisely campaign" also emphasizes the need to have ongoing cost/benefit discussions regarding care of preterm newborns to avoid waste that comes from subjecting infants to procedures that do not help. We performed a MEDLINE EMBASE database review from 2000 to 2018 to account for the technical evolution in the cranial ultrasound machines and introduction of MRI imaging in the NICU. Studies were graded based on the strength of their design using the GRADE guidelines and summarized with respect to brain MRI vs. cranial US (1) detection of white matter injury; (2) cerebellar hemorrhage; (3) long-term neurodevelopmental outcomes and impact on parental anxiety. We conclude with a hospital-specific guideline algorithm for performing TEA MRI based on risk evaluations ≤32 weeks.

Neurodevelopmental outcomes following necrotizing enterocolitis

Necrotizing enterocolitis (NEC), a gastrointestinal emergency predominantly affecting premature infants, is associated with increased risk for poor neurodevelopmental outcomes. NEC often strikes during a period of rapid and dynamic neurologic development when the brain is particularly vulnerable to insults and nutrient deficits. The pathogenesis of neurodevelopmental impairment following NEC is likely multifactorial, with both nutritional and non-nutritional factors at play. Follow-up testing that ensures early detection and intervention for impairments is crucial to optimize neurodevelopmental outcomes following NEC. A multifaceted approach to follow-up after NEC is necessary, with close monitoring of growth, serial developmental assessments, neurologic examinations, hearing and vision testing and neuroimaging. Further research is needed to understand the pathogenesis of neurodevelopmental impairment following NEC, to identify more targeted follow-up tests, and to discover interventions aimed at optimizing neurodevelopmental outcomes following NEC.

Preterm neuroimaging and neurodevelopmental outcome: a focus on intraventricular hemorrhage, post-hemorrhagic hydrocephalus, and associated brain injury

Intraventricular hemorrhage in the setting of prematurity remains the most common cause of acquired hydrocephalus. Neonates with progressive post-hemorrhagic hydrocephalus are at risk for adverse neurodevelopmental outcomes. The goal of this review is to describe the distinct and often overlapping types of brain injury in the preterm neonate, with a focus on neonatal hydrocephalus, and to connect injury on imaging to neurodevelopmental outcome risk. Head ultrasound and magnetic resonance imaging findings are described separately. The current state of the literature is imprecise and we end the review with recommendations for future radiologic and neurodevelopmental research.

Neurological outcome at 6 and 12 months corrected age in hospitalised late preterm infants -a prospective study

Late preterm infants (34-0/7 to 36-6/7 weeks" gestation) account for 10-20% of NICU admissions and are at increased risk for morbidity and mortality. Although they are prone to developmental delays, reports on neurological outcome during the first 2 years of life are scarce. The aim of the study was to assess neurological/neuromotor outcome in high risk late preterm infants at 6 and 12 months corrected age and the change in neurological scores over time, and to identify factors associated with the neurological outcome. The Hammersmith Infant Neurological Examination was performed in a cohort of 157 late preterm infants admitted in the NICU. The infants were examined at 6 and 12 months corrected age respectively and scored with the optimality score system including 26 items assessing cranial nerve function, posture, movements, tone and reflexes. Also parents reported neurological milestones in the follow up visit. Infants at 6 months had a global score of 59 (47-76) and optimal scores achieved in 25.4%. At 12 months they had a global score of 70 (58-78) and achieved optimal scores in 63.2%. The subscores of posture, tone and reflexes gradually increased from 6 to 12 months corrected age. Being born small for gestational age was the only factor that adversely influenced HINE score at 6 and 12 months. At 12 months 58.5% achieved independent walking. High risk late preterm infants have suboptimal HINE scores at 6 and 12 months of age, suggesting a need for closer follow up and early intervention programs.

Annual Research Review: Not just a small adult brain: understanding later neurodevelopment through imaging the neonatal brain

BACKGROUND

There has been a recent proliferation in neuroimaging research focusing on brain development in the prenatal, neonatal and very early childhood brain. Early brain injury and preterm birth are associated with increased risk of neurodevelopmental disorders, indicating the importance of this early period for later outcome.

SCOPE AND METHODOLOGY

Although using a wide range of different methodologies and investigating diverse samples, the common aim of many of these studies has been to both track normative development and investigate deviations in this development to predict behavioural, cognitive and neurological function in childhood. Here we review structural and functional neuroimaging studies investigating the developing brain. We focus on practical and technical complexities of studying this early age range and discuss how neuroimaging techniques have been successfully applied to investigate later neurodevelopmental outcome.

CONCLUSIONS

Neuroimaging markers of later outcome still have surprisingly low predictive power and their specificity to individual neurodevelopmental disorders is still under question. However, the field is still young, and substantial challenges to both acquiring and modeling neonatal data are being met.

Neurodevelopmental and Behavioral Outcomes in Extremely Premature Neonates With Ventriculomegaly in the Absence of Periventricular-Intraventricular Hemorrhage

IMPORTANCE

Studies of cranial ultrasonography and early childhood outcomes among cohorts of extremely preterm neonates have linked periventricular-intraventricular hemorrhage and cystic periventricular leukomalacia with adverse neurodevelopmental outcomes. However, the association between nonhemorrhagic ventriculomegaly and neurodevelopmental and behavioral outcomes is not fully understood.

OBJECTIVE

To characterize the outcomes of extremely preterm neonates younger than 27 weeks' gestational age who experienced nonhemorrhagic ventriculomegaly that was detected prior to 36 weeks' postmenstrual age.

DESIGN, SETTING, AND PARTICIPANTS

This longitudinal observational study was conducted at 16 centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network. Infants born prior to 27 weeks' gestational age in any network facility between July 1, 2006, and June 30, 2011, were included if they had a cranial ultrasonogram performed prior to 36 weeks' postmenstrual age. Comparisons were made between those with ventriculomegaly and those with normal cranial sonograms. Data analysis was completed from August 2013 to August 2017.

MAIN OUTCOMES AND MEASURES

The main outcome was neurodevelopmental impairment, defined as a Bayley Scales of Infant and Toddler Development III cognitive score less than 70, moderate/severe cerebral palsy, a Gross Motor Function Classification System score of level 2 or more, vision impairment, or hearing impairment. Secondary outcomes included Bayley Scales of Infant and Toddler Development III subscores, components of neurodevelopmental impairment, behavioral outcomes, and death/neurodevelopmental impairment. Logistic regression was used to evaluate the association of ventriculomegaly with adverse outcomes while controlling for potentially confounding variables and center differences as a random effect. Linear regression was used similarly for continuous outcomes.

RESULTS

Of 4193 neonates with ultrasonography data, 300 had nonhemorrhagic ventriculomegaly (7%); 3045 had normal cranial ultrasonograms (73%), 775 had periventricular-intraventricular hemorrhage (18.5%), and 73 had cystic periventricular leukomalacia (1.7%). Outcomes were available for 3008 of 3345 neonates with ventriculomegaly or normal scans (90%). Compared with normal cranial ultrasonograms, ventriculomegaly was associated with lower gestational age, male sex, and bronchopulmonary dysplasia, late-onset sepsis, meningitis, necrotizing enterocolitis, and stage 3 retinopathy of prematurity. After adjustment, neonates with ventriculomegaly had higher odds of neurodevelopmental impairment (odds ratio [OR], 3.07; 95% CI, 2.13-4.43), cognitive impairment (OR, 3.23; 95% CI, 2.09-4.99), moderate/severe cerebral palsy (OR, 3.68; 95% CI, 2.08-6.51), death/neurodevelopmental impairment (OR, 2.17; 95% CI, 1.62-2.91), but not death alone (OR, 1.09; 95% CI, 0.76-1.57). Behavioral outcomes did not differ.

CONCLUSIONS AND RELEVANCE

Nonhemorrhagic ventriculomegaly is associated with increased odds of neurodevelopmental impairment among extremely preterm neonates.

Advanced Pediatric Neurosonography Techniques: Contrast-Enhanced Ultrasonography, Elastography, and Beyond

Recent technical advances in neurosonography continue broadening the diagnostic utility, sensitivity, and specificity of ultrasound for detecting intracranial abnormalities bed side. The clinical and functional applications of neurosonography have significantly expanded since the 1980s when transcranial Doppler sonography first allowed anatomic and hemodynamic delineation of the intracranial vessels through the thin temporal skull. In the past few years, contrast-enhanced ultrasonography, elastography, 3D/4D reconstruction tools, and high-resolution microvessel imaging techniques have further enhanced the diagnostic significance of neurosonography. Given these advances, a thorough familiarity with these new techniques and devices is crucial for a successful clinical application allowing improved patient care. It is essential that future neurosonography studies compare these advanced techniques against the current "gold standard" computed tomography and magnetic resonance imaging to assure the accuracy of their diagnostic potential. This review will provide a comprehensive update on currently available advanced neurosonography techniques.