The effects of mild germinal matrix-intraventricular haemorrhage on the developmental white matter microstructure of preterm neonates: a DTI study

VP3.15 reduces acute cerebellum damage after germinal matrix-intraventricular hemorrhage of the preterm newborn

Germinal matrix-intraventricular hemorrhage (GM-IVH) is one of the most common complications of the preterm newborn. The pathology of the GM-IVH is not completely understood and even regions distant from the lesion area are severely affected. It has been suggested that cerebellar diaschisis may underlie the neurodevelopmental problems that many of these kids show, including cerebral palsy, attention deficit disorders or hyperactivity. Additionally, GM-IVH has no successful treatment. VP3.15 is a dual action phosphodiesterase 7 (PDE7) and glycogen synthase kinase-3β (GSK-3β) inhibitor that limits neuroinflammation and neuronal loss. Therefore, it might also provide a relevant tool to reduce complications associated with GM-IVH. We have used a murine model of GM-IVH to analyze the short and long-term effects of VP3.15 in brain pathology and behavioral complications. In our hands, the induction of unilateral GM-IVH to P7 CD1 mice results in a short-term (P14) compromise of the cerebellar neuronal population and Purkinje cells arborization, an increase of microglia burden in the nuclei and an overall increase of punctuate cerebellar hemorrhages. Whereas brain alterations are no longer observed in the long term (P110), these animals present overt hyperactivity when analyzed in the adulthood, supporting the long-term behavioral impairment. Also, hyperactivity significantly correlates with ipsi and contralateral cerebellar sizes, neuronal densities and myelin basic protein levels. Importantly, treatment with VP3.15 significantly reduces neuronal loss, Purkinje cells simplification, the presence of cerebellar hemorrhages, as well as hyperactivity. Altogether, our data support the neuroprotective effects of VP3.15 in GM-IVH of the PT.

Utility of Diffusion Tensor Imaging in Preterm Infants with Germinal Matrix Hemorrhage and Intraventricular Hemorrhage: A Systematic Review

OBJECTIVE

Intraventricular hemorrhage (IVH) and germinal matrix hemorrhage (GMH) are the most common brain injuries in preterm infants. Neonates with these injuries are at greater risk of impaired neurodevelopmental outcome. Current guidelines recommend screening infants with cranial ultrasound (CUS); however, this is prone to missing subtle injury patterns, particularly within the posterior fossa. The present report sought to discuss the utility of diffusion tensor imaging (DTI) in preterm infants.

METHODS

A systematic review of PubMed, Ovid MEDLINE, and Ovid EMBASE was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Included manuscripts were methodically scrutinized for quality, DTI use, and neurologic outcome.

RESULTS

Twenty studies with 1574 infants who underwent DTI were included. There were 574 preterm infants with GMH-IVH on DTI. Twelve studies documented decreased fractional anisotropy, whereas 6 demonstrated structural segregation and asymmetrical white matter myelination in these infants. Seven studies documented concurrent CUS use with 2 studies comparing DTI findings with CUS findings. In both studies, DTI more accurately detected presence of GMH, especially within the cerebellum. Among GMH-IVH preterm infants, 58.5% demonstrated cognitive, intellectual, and language delays at follow-up (mean, 32.4 months). Additionally, lower fractional anisotropy values on initial DTI were associated with cognitive, language, and motor delays.

CONCLUSIONS

Although DTI is more sensitive for picking up subtle injury patterns, CUS remains the standard of care when screening for injuries that would necessitate surgical intervention. DTI offers a refined understanding of the sequelae of GMH-IVH with microstructural changes found on DTI being associated with childhood motor and cognitive outcomes.

Do Different Amounts of Exogenous Surfactant Differently Influence Cerebrovascular Instability in a Consecutive Group of Preterm Babies? Preliminary Results from a Single-Center Experience

BACKGROUND

Thirty years ago, the first attempt by Saliba and colleagues was made to reduce the negative effects (hypercarbia) of exogenous surfactant (ES) by slowing its administration. Sixteen years later, we observed the first less invasive surfactant administration (LISA) attempt by Kribs and colleagues. Many studies, since that time, have tried to minimize the invasiveness of ES and subsequent cerebral blood flow perturbations through studies using near-infrared spectroscopy (NIRS). We sought to address this medical challenge by identifying a less problematic modality of ES administration by delivering multiple aliquots of ES instead of a single one, as typically performed. The aim of this study was to test the hypothesis that a different way of administering ES using more aliquots could be a safe alternative that should be assessed in further studies.

METHODS

Patients between 26 + 0 and 35 + 6 weeks of gestational age (GA) requiring ES administration were enrolled (April 2023-February 2024). Differently fractioned doses were delivered according to an arbitrary standard dosage (0.3 mL per aliquot in babies < 29 weeks; 0.6 mL in babies ≥ 29 weeks), while NIRS and transcutaneous CO2 (tCO2) monitoring were always performed. ES's effectiveness was assessed based on the reduction in the Oxygen Saturation Index (OSI) after administration. Persistent desaturation, bradycardia, and airway obstruction were defined as adverse effects and used to evaluate safety during ES administration, as well as variability in NIRS-rSO2 values and tCO2.

RESULTS

Twenty-four patients were enrolled with a median GA of 29 weeks (IQR 4.5) and BW of 1223 ± 560 g. In addition, 50% of the cohort received fewer than three aliquots, whereas the other 50% received more than three. Monitoring was started before the procedure and continued 30' after the last ES aliquot administration. The variability in NIRS-SpO2 values was significantly higher in the group (p = 0.007) with a lower number of aliquots administered. Similarly, increased NIRS-rSO2 values (p = 0.003) and increased tCO2 levels (p = 0.005) were observed in infants who underwent an ES split after the administration of a low number of aliquots.

CONCLUSIONS

Our data obtained from the group with > 3 fractionated doses of ES seem to justify the preparation of a more robust study, as the combination of reduced NIRS variability and reduced tCO2 maximum levels is consistent with more stable cerebral blood flow during the challenging time of ES administration.

Associations between diffusion kurtosis imaging metrics and neurodevelopmental outcomes in neonates with low-grade germinal matrix and intraventricular hemorrhage

Diffusion Kurtosis Imaging (DKI)-derived metrics are recognized as indicators of maturation in neonates with low-grade germinal matrix and intraventricular hemorrhage (GMH-IVH). However, it is not yet known if these factors are associated with neurodevelopmental outcomes. The objective of this study was to acquire DKI-derived metrics in neonates with low-grade GMH-IVH, and to demonstrate their association with later neurodevelopmental outcomes. In this prospective study, neonates with low-grade GMH-IVH and control neonates were recruited, and DKI were performed between January 2020 and March 2021. These neonates underwent the Bayley Scales of Infant Development test at 18 months of age. Mean kurtosis (MK), radial kurtosis (RK) and gray matter values were measured. Spearman correlation analyses were conducted for the measured values and neurodevelopmental outcome scores. Forty controls (18 males, average gestational age (GA) 30 weeks ± 1.3, corrected GA at MRI scan 38 weeks ± 1) and thirty neonates with low-grade GMH-IVH (13 males, average GA 30 weeks ± 1.5, corrected GA at MRI scan 38 weeks ± 1). Neonates with low-grade GMH-IVH exhibited lower MK and RK values in the PLIC and the thalamus (P < 0.05). The MK value in the thalamus was associated with Mental Development Index (MDI) (r = 0.810, 95% CI 0.695-0.13; P < 0.001) and Psychomotor Development Index (PDI) (r = 0.852, 95% CI 0.722-0.912; P < 0.001) scores. RK value in the caudate nucleus significantly and positively correlated with MDI (r = 0.496, 95% CI 0.657-0.933; P < 0.001) and PDI (r = 0.545, 95% CI 0.712-0.942; P < 0.001) scores. The area under the curve (AUC) were used to assess diagnostic performance of MK and RK in thalamus (AUC = 0.866, 0.787) and caudate nucleus (AUC = 0.833, 0.671) for predicting neurodevelopmental outcomes. As quantitative neuroimaging markers, MK in thalamus and RK in caudate nucleus may help predict neurodevelopmental outcomes in neonates with low-grade GMH-IVH.

Ventilatory Support, Extubation, and Cerebral Perfusion Changes in Pre-Term Neonates: A Near Infrared Spectroscopy Study

Early extubation is considered to be beneficial for pre-term neonates. On the other hand, premature extubation can cause lung derecruitment, compromised gas exchange, and need for reintubation, which may be associated with severe brain injury caused by sudden cerebral blood flow changes. We used near infrared spectroscopy (NIRS) to investigate changes in cerebral oxygenation (rScO2) and fractional tissue oxygen extraction (+) after extubation in pre-term infants. This is a single-center retrospective study of NIRS data at extubation time of all consecutive pre-term neonates born at our institution over a 1-year period. Comparison between subgroups was performed. Nineteen patients were included; average gestational age (GA) was 29.4 weeks. No significant change was noted in rScO2 and cFTOE after extubation in the whole population. GA and germinal matrix hemorrhage (GMH)-intraventricular hemorrhage (IVH) showed a significant change in rScO2 and cFTOE after extubation. A significant increase in cFTOE was noted in patients with previous GMH-IVH (+0.040; p = 0.05). To conclude, extubation per se was not associated with significant change in cerebral oxygenation and perfusion. Patients with a diagnosed GMH-IVH showed an increase in cFTOE, suggesting perturbation in cerebral perfusion suggesting further understanding during this challenging phenomenon. Larger studies are required to corroborate our findings.

Assessment of brain structure and volume reveals neurodevelopmental abnormalities in preterm infants with low-grade intraventricular hemorrhage

There is increasing evidence of abnormal neurodevelopmental outcomes in preterm infants with low-grade intraventricular hemorrhage (IVH). The purpose of the study was to explore whether brain microstructure and volume are associated with neuro-behavioral outcomes at 40 weeks corrected gestational age in preterm infants with low-grade IVH. MR imaging at term-equivalent age (TEA) was performed in 25 preterm infants with mild IVH (Papile grading I/II) and 40 control subjects without IVH. These subjects all had neonatal behavioral neurological assessment (NBNA) at 40 weeks' corrected age. Microstructure and volume evaluation of the brain were performed by using diffusion kurtosis imaging (DKI) and Synthetic MRI. Correlations among microstructure parameters, volume, and developmental outcomes were explored by using Spearman's correlation. In preterm infants with low-grade IVH, the volume of brain parenchymal fraction (BPF) was reduced. In addition, mean kurtosis (MK), fractional anisotropy (FA), radial kurtosis (RK), axial kurtosis (AK) in several major brain regions were reduced, while mean diffusivity (MD) was increased (P < 0.05). BPF, RK in the cerebellum, MK in the genu of the corpus callosum, and MK in the thalamus of preterm infants with low-grade IVH were associated with lower NBNA scores (r = 0.831, 0.836, 0.728, 0.772, P < 0.05). DKI and Synthetic MRI can quantitatively evaluate the microstructure alterations and brain volumes in preterm infants with low-grade IVH, which provides clinicians with a more comprehensive and accurate neurobehavioral assessment of preterm infants with low-grade IVH.

Neurodevelopmental Outcome at 3 Years of Age in Very Low Birth Weight Infants According to Brain Development and Lesions

BACKGROUND

During the last decades, severe brain lesions affecting very low birth weight (<1500 gr, VLBW) infants were gradually substituted by milder lesions with debatable prognoses.

OBJECTIVE

The objective of this study is to define type, frequency and 3 years of neurodevelopmental outcome of prematurity-related brain lesions in a modern cohort of VLBW infants.

METHODS

VLBW infants admitted to our NICU in 5 years period with brain MRI at term-equivalent age were included. MRI scans were reviewed to identify and grade white matter lesions (WML), intraventricular hemorrhage (IVH), and cerebellar hemorrhage (CBH). Linear measurements of brain size, biparietal width (BPW) and trans-cerebellar diameter (TCD) were carried out. Total maturation score (TMS) was calculated. Developmental Coefficients (DQ) on Griffiths Scale at 3 years of age were compared between patients with different types and grades of lesions and patients without lesions; possible correlations between linear brain measurements, brain maturation and outcome were explored.

RESULTS

Study included 407 patients. Of them, 187 (46%) had at least one brain lesion on MRI, while 37 (9%) had severe lesions. The most frequent lesion was IVH (28%), followed by WML (21%) and CBH (17%). Mild and severe IVH, moderate and severe WML and all grades of CBH were related to worst outcome at 3 years. In patients without lesions, small BPW and small TCD were associated with worse outcomes. No correlations were observed between TMS and outcome.

CONCLUSION

We have observed that even mild brain lesions have a negative influence on neurological outcome at 3 years of age.

White matter microstructure predicts individual differences in infant fear (But not anger and sadness)

We examine neural correlates of discrete expressions of negative emotionality in infants to determine whether the microstructure of white matter tracts at 1 month of age foreshadows the expression of specific negative emotions later in infancy. Infants (n = 103) underwent neuroimaging at 1-month, and mothers reported on infant fear, sadness, and anger at 6, 12, and 18 months using the Infant Behavior Questionnaire-Revised. Levels and developmental change in fear, sadness, and anger were estimated from mother reports. Relations between MRI and infant emotion indicated that 1-month white matter microstructure was differentially associated with level and change in infant fear, but not anger or sadness, in the left stria terminalis (p < 0.05, corrected), a tract that connects frontal and tempo-parietal regions and has been implicated in emerging psychopathology in adults. More relaxed constraints on significance (p < 0.10, corrected) revealed that fear was associated with lower white matter microstructure bilaterally in the inferior portion of the stria terminalis and regions within the sagittal stratum. Results suggest the neurobehavioral uniqueness of fear as early as 1 month of age in regions that are associated with potential longer-term outcomes. This work highlights the early neural precursors of fearfulness, adding to literature explaining the psychobiological accounts of affective development. HIGHLIGHTS: Expressions of infant fear and anger, but not sadness, increase from 6 to 18 months of age. Early neural architecture in the stria terminalis is related to higher initial levels and increasing fear in infancy. After accounting for fear, anger and sadness do not appear to be associated with differences in early white matter microstructure. This work identifies early neural precursors of fearfulness as early as 1-month of age.

Deep cerebral venous abnormalities in premature babies with GMH-IVH: a single-centre retrospective study

PURPOSE

Germinal matrix haemorrhage/intraventricular haemorrhage (GMH-IVH) is a multifactorial injury with both anatomic and haemodynamic involvement. Normal variants in preterm deep cerebral venous anatomy associated with GMH-IVH have been previously described using MRI susceptibility weighted imaging (SWI). The aims of this study were to use SWI to compare the deep venous systems of a cohort of preterm neonates with various grades of GMH-IVH to a group of age-matched controls without GMH-IVH and to present novel retrospective SWI imaging findings.

METHODS

A neuroradiologist retrospectively evaluated 3T MRI SWI and phase imaging of 56 preterm neonates with GMH-IVH (14 of each grade) and 27 controls without GMH-IVH, scoring the venous irregularities according to three variables: decreased venous patency, increased lumen susceptibility and the presence of collaterals. Eight different venous locations, including indicated bilateral components, were evaluated: straight sinus, vein of galen, internal cerebral, direct lateral, thalamostriate, atrial and the anterior septal veins. Variables were analysed for statistical significance. Inter-rater reliability was determined via subset evaluation by a second paediatric radiologist.

RESULTS

Deep venous abnormalities were significantly more common in patients with GMH-IVH, with Wilcoxon Rank Sum Test demonstrating significant increase with GMH-IVH for total decreased venous patency (W=0, p<0.0001), increased lumen susceptibility and collateral formation. Venous abnormalities were also positively correlated with an increase in GMH-IVH grade from I to IV (patency, ρ=0.782, p<0.01) (increased lumen susceptibility, ρ=0.739, p<0.01) (collaterals, ρ=0.649, p<0.01), not just GMH-IVH alone.

CONCLUSION

Deep venous abnormalities are significantly correlated with GMH-IVH alone and an increase in GMH-IVH grade. Further study is needed to determine cause and effect.

Impact of low-grade intraventricular hemorrhage on neurodevelopmental outcome in very preterm infants at two years of age

BACKGROUND

High-grade intraventricular hemorrhage (IVH) in very preterm infants is a known risk factor for adverse neurodevelopmental outcome. Prognosis is less clear for low-grade (grades I/II) IVH however, with conflicting study results in recent years.

OBJECTIVE

To evaluate the impact of low-grade IVH on neurodevelopmental outcome at 2 years corrected age in preterm infants born below 32 weeks gestation at the University hospital of Zurich between 2009 and 2014.

METHODS

Among 843 live-born preterm infants born during the observation period, 509 were included in our study. Exclusion criteria were death, high-grade IVH, cystic periventricular leukomalacia and congenital malformations. Infants were grouped into those with or without low-grade IVH according to cranial ultrasound. Neurodevelopmental impairment (NDI) was defined as cognitive or motor developmental score > 2 standard deviations below the mean and/or CP grades 2-5 and/or moderate/severe vision loss and/or hearing problem corrected with hearing aids. Multivariate linear regression was used to assess effect of low-grade IVH on endpoints while adjusting for other risk factors.

RESULTS

87 preterm infants had low-grade IVH (42 grade I, 45 grade II) on cranial ultrasound. These were compared to 422 preterm infants without IVH. Follow-up rate was 82.4 %. Preterm infants with low-grade IVH had higher rates of NDI (21.8 vs 13.3 %, p = 0.047). Infants with IVH grade II had significantly higher rates for CP (8.9 % vs 3.6 %, p = 0.003), visual impairment (20.5 % vs 8.3 %, p = 0.009) and NDI (33.3 % vs 13.3 %, p < 0.001).

CONCLUSION

In our study, low-grade IVH - and especially IVH grade II - is associated with adverse neurodevelopmental outcome at 2 years of corrected age.

Racial disparities in the development of comorbid conditions after preterm birth: A narrative review

Despite recognition and attempts to reduce racial disparities in perinatal outcomes, Black infants are still disproportionately represented among those who are born preterm. Postnatal investigations of racial disparities in comorbidities and outcomes after preterm birth are increasing, although their results and interpretations are conflicting. In the present review, we 1.) identify important methodological limitations of that literature 2.) summarize the conflicting literature investigating racial disparities, specifically Black-white differences, in postnatal comorbidities and outcomes after preterm birth 3.) describe mechanisms by which racism operates to contextualize our understanding to inform future work to actively reduce disparities in preterm birth and subsequently, its complications.

Clinical factors associated with abnormal general movements of preterm newborns during hospitalization in a neonatal intensive care unit

INTRODUCTION

There is no clarity about which clinical variables during hospitalization in the Neonatal Intensive Care Unit (NICU) are associated with abnormal General Movements (GMs).

OBJECTIVE

To describe the trajectory of GMs of preterm newborns and explore the association between clinical variables and the presence of abnormal GMs during the NICU stay.

METHODS

Fifty-eight preterm newborns (33 males), with a mean gestational age at birth of 31,93 week's postmenstrual age, were evaluated using the GMs assessment by Hadders-Algra method. Clinical variables recorded weekly throughout the hospitalization period. The weekly association between clinical variables and the presence of abnormal GMs was tested using the Generalized Estimating Equations (GEE) model.

RESULTS

Preterm infants were recorded for up to sixteen weeks and more than half of the infants (56.9 %) had abnormal movements in at least one week during hospitalization. The absence of peri-intraventricular hemorrhage (PIVH) grades I-II and non-invasive ventilatory support and/or oxygen therapy on the day of the evaluation reduced, respectively, by 77.3 % (OR = 0.23; p > 0.0001) and 64.3 % (OR = 0.36; p > 0.0001) the chance of having an abnormal classification. In addition, each day of increased invasive mechanical ventilation increased the chance of having an abnormal classification by 1.11 times (OR = 0.025; p > 0.0001).

CONCLUSION

PIVH grades I-II, longer durations of mechanical ventilation and the presence of non-invasive ventilatory support and/or oxygen therapy are associated with abnormal movements during stay in the neonatal period. The data suggest that development outcome of infants having these conditions should be closely monitored.

Neuroimaging of structural and functional connectivity in preterm infants with intraventricular hemorrhage

Preterm infants with intraventricular hemorrhage (IVH) are known to have some of the worst neurodevelopmental outcomes in all of neonatal medicine, with a growing body of evidence relating these outcomes to underlying disruptions in brain structure and function. This review begins by summarizing state-of-the-art neuroimaging techniques delineating structural and functional connectivity (diffusion and resting state functional MRI) and their application in infants with IVH, including unique technical challenges and emerging methods. We then review studies of altered structural and functional connectivity, highlighting the role of IVH severity and location. We subsequently detail investigations linking structural and functional findings in infancy to later outcomes in early childhood. We conclude with future directions including methodologic considerations for prospective and potentially interventional studies designed to mitigate disruptions to underlying structural and functional connections and improve neurodevelopmental outcomes in this high-risk population.

The Impact of Different Degrees of Intraventricular Hemorrhage on Mortality and Neurological Outcomes in Very Preterm Infants: A Prospective Cohort Study

Objective

Intraventricular hemorrhage (IVH) is a common complication in preterm infants and is related to neurodevelopmental outcomes. Infants with severe IVH are at higher risk of adverse neurological outcomes and death, but the effect of low-grade IVH remains controversial. The purpose of this study was to evaluate the impact of different degrees of IVH on mortality and neurodevelopmental outcomes in very preterm infants.

Methods

Preterm infants with a gestational age of &lt;30 weeks admitted to neonatal intensive care units were included. Cerebral ultrasound was examined repeatedly until discharge or death. All infants were followed up to 18–24 months of corrected age. The impact of different grades of IVH on death and neurodevelopmental disability was assessed by multiple logistic regression.

Results

A total of 1,079 preterm infants were included, and 380 (35.2%) infants had grade I-II IVH, 74 (6.9%) infants had grade III-IV IVH, and 625 (57.9%) infants did not have IVH. The mortality in the non-IVH, I-II IVH, and III-IV IVH groups was 20.1, 19.7, and 55.2%, respectively (p &lt; 0.05), and the incidence of neurodevelopmental disabilities was 13.9, 16.1, and 43.3%, respectively (p &lt; 0.05), at 18–24 months of corrected age. After adjusting for confounding factors, preterm infants with III-IV IVH had higher rates of cerebral palsy [26.7 vs. 2.4%, OR = 6.10, 95% CI (1.840–20.231), p = 0.003], disability [43.3 vs. 13.9%, OR = 2.49, 95% CI (1.059–5.873), p = 0.037], death [55.2 vs. 20.1%, OR = 3.84, 95% CI (2.090–7.067), p &lt; 0.001], and disability + death [73.7 vs. 28.7%, OR = 4.77, 95% CI (2.518–9.021), p &lt; 0.001] compared to those without IVH. However, the mortality and the incidence of neurodevelopmental disability in infants with I-II IVH were similar to those without IVH (p &gt; 0.05).

Conclusions

Severe IVH but not mild IVH increased the risk of mortality and neurodevelopmental disability in very preterm infants.

Adenosine Blood Level: A Biomarker of White Matter Damage in Very Low Birth Weight Infants

BACKGROUND

Very low birth weight infants are at risk of developing periventricular white matter lesions. We previously reported high blood adenosine levels in premature infants and infants with low birth weight. We asked whether blood adenosine levels could be related to the vulnerability of the maturing white matter to develop lesions. The present study aims at finding a biomarker for the early detection of brain white matter lesions that can profoundly influence the neurodevelopmental outcome, whose pathophysiology is still unclear.

METHODS

Dried blood spots were prospectively collected for the newborn screening program and adenosine concentration measurements. Fifty-six newborns who tested four times for blood adenosine concentration (at days 3, 15, 30, and 40 post-birth) were included in the program. All infants underwent brain MRI at term equivalent age. Neurodevelopmental outcomes were studied with Griffiths Mental Development Scales (GMDS) at 12 ± 2 months corrected age.

RESULTS

Blood adenosine concentration increased over time from a median of 0.75 μM at Day 3 to 1.46 μM at Day 40. Adenosine blood concentration >1.58 μM at Day 15 was significantly associated with brain white matter lesions at MRI (OR (95 % CI) of 50.0 (3.6-688.3), p-value < 0.001). A moderate negative correlation between adenosine at 15 days of life and GMDS at 12 ± 2 months corrected age was found.

CONCLUSION

These findings suggest a potential role for blood adenosine concentration as a biomarker of creberal white matter lesions in very low birth weight infants.

Low-grade IVH in preterm infants causes cerebellar damage, motor, and cognitive impairment

BACKGROUND

Few studies have examined the effect of low-grade intraventricular hemorrhage (IVH) on the white matter in the cerebellum and its association with neurodevelopment. We evaluated cerebellar white matter at term-equivalent age (TEA) in preterm infants with low-grade IVH. Furthermore, we assessed neurodevelopmental outcomes at 3 years of age to examine the influence of low-grade IVH on neurodevelopment.

METHODS

Thirteen infants with low-grade IVH and 26 without IVH, born at <30 weeks' postmenstrual age (PMA), were enrolled in this study. Diffusion tensor imaging (DTI) parameters, including fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in the middle and superior cerebellar peduncles (SCP), were measured. Neurodevelopmental outcomes at three years of age were assessed and the correlation between DTI parameters and developmental quotient (DQ) was analyzed.

RESULTS

Preterm infants with IVH showed lower FA values (P < 0.01) and higher ADC values (P < 0.05) in the SCP at TEA than the no-IVH group. Lower Postural-Motor and Cognitive-Adaptive DQ at 3 years of age were observed in the IVH compared to the no-IVH group. A significant correlation between the FA values in the SCP at TEA and the Posture-Motor DQ was observed at three years of age (P = 0.043, r = 0.50).

CONCLUSIONS

These data suggest that low-grade IVH in preterm infants affects the SCP at TEA and that impaired cerebellar white matter correlates with poor motor development at three years of age.

External ventricular drainage for posthemorrhagic ventricular dilatation in preterm infants: insights on efficacy and failure

OBJECTIVE

The objective of this study was to describe the clinical and neuroradiological characteristics of a cohort of preterm infants who had undergone external ventricular drain insertion as a temporary measure to treat posthemorrhagic ventricular dilatation. In addition, the authors investigated the factors predicting permanent shunt dependency.

METHODS

The authors retrospectively reviewed the medical records of a cohort of preterm infants who had undergone external ventricular drain insertion at Gaslini Children's Hospital (Genoa, Italy) between March 2012 and February 2018. They also analyzed clinical characteristics and magnetic resonance imaging data, including diffusion- and susceptibility-weighted imaging studies, which were obtained before both catheter insertion and removal.

RESULTS

Twenty-eight infants were included in the study. The mean gestational age was 28.2 ± 2.7 weeks, and the mean birth weight was 1209 ± 476 g. A permanent ventriculoperitoneal shunt was inserted in 15/28 (53.6%) infants because of the failure of external ventricular drainage as a temporary treatment option. Compared with the shunt-free group, the shunt-dependent group had a significantly lower gestational age (29.3 ± 2.3 vs 27.2 ± 2.7 weeks, p = 0.035) and tended toward a lower birth weight (p = 0.056). None of the clinical and neuroradiological characteristics significantly differed between the shunt-free and shunt-dependent groups at the time of catheter insertion. As expected, ventricular parameters as well as the intraventricular extension of intracerebral hemorrhage, as assessed using the intraventricular hemorrhage score, were reportedly higher in the shunt-dependent group than in the shunt-free group before catheter removal.

CONCLUSIONS

External ventricular drainage is a reliable first-line treatment for posthemorrhagic hydrocephalus. However, predicting its efficacy as a unique treatment remains challenging. A lower gestational age is associated with a higher risk of posthemorrhagic hydrocephalus progression, suggesting that the more undeveloped the mechanisms for the clearance of blood degradation products, the greater the risk of requiring permanent cerebrospinal fluid diversion, although sophisticated MRI investigations are currently unable to corroborate this hypothesis.

Structural and functional brain connectivity in moderate-late preterm infants with low-grade intraventricular hemorrhage

PURPOSE

Brain functional connectivity (FC) changes and microstructural abnormalities are reported in infants born moderate and late preterm (MLPT). We evaluated the effect of low-grade (grades I, II) intraventricular hemorrhage (IVH) in MLPT babies on brain structural connectivity (SC) and FC.

METHODS

Babies born MLPT between January 2014 and May 2017 underwent brain ultrasound (US) at 72 h and 7 days after birth, and MRI at around term equivalent. The MRI protocol comprised T1- and T2-weighted sequences, diffusion tensor imaging (DTI), and resting-state functional MRI (fMRI). SC and FC were assessed using graph analysis.

RESULTS

Of 350 MLPT neonates, 15 showed low-grade IVH on US at 72 h, for which brain MRI was available in 10. These 10 infants, with mean gestational age (GA) 34.0 ± 0.8 weeks, comprised the study group, and 10 MLPT infants of mean GA 33.9 ± 1.1 weeks, with no abnormalities on brain US and MRI, were control subjects. All study subjects presented modularity, small world topology, and rich club organization for both SC and FC. The patients with low-grade IVH had lower FC rich club coefficient and lower SC betweenness centrality in the left frontoparietal operculum, and lower SC rich club coefficient in the right superior orbitofrontal cortex than the control subjects.

CONCLUSIONS

Topological and functional properties of mature brain connectivity are present in MLPT infants. IVH in these infants was associated with structural and functional abnormalities in the left frontoparietal operculum and right orbitofrontal cortex, regions related to language and cognition.

Nosological Differences in the Nature of Punctate White Matter Lesions in Preterm Infants

Background: The pathogenesis of punctuate white matter lesions (PWMLs), a mild form of white matter damage observed in preterm infants, is still a matter of debate. Susceptibility-weighted imaging (SWI) allows to differentiate PWMLs based on the presence (SWI+) or absence (SWI-) of hemosiderin, but little is known about the significance of this distinction. This retrospective study aimed to compare neuroradiological and clinical characteristics of SWI+ and SWI- PWMLs. Materials and Methods: MR images of all VLBW infants scanned consecutively at term-equivalent age between April 2012 and May 2018 were retrospectively reviewed, and infants with PWMLs defined as small areas of high T1 and/or low T2 signal in the periventricular white matter were selected and included in the study. Each lesion was analyzed separately and characterized by localization, organization pattern, and distance from the lateral ventricle. Clinical data were retrieved from the department database. Results: A total of 517 PWMLs were registered in 81 patients, with 93 lesions (18%) visible on SWI (SWI+), revealing the presence of hemosiderin deposits. On univariate analysis, compared to SWI- PWML, SWI+ lesions were closer to the ventricle wall, more frequently organized in linear pattern and associated with lower birth weight, lower gestational age, lower admission temperature, need for intubation, bronchopulmonary dysplasia, retinopathy of prematurity, and presence of GMH-IVH. On multivariate analysis, closer distance to the ventricle wall on axial scan and lower birth weight were associated with visibility of PMWLs on SWI (p = 0.003 and p = 0.0001, respectively). Conclusions: Our results suggest a nosological difference between SWI+ and SWI- PWMLs. Other prospective studies are warranted to corroborate these observations.

Effects of intraventricular hemorrhage on white matter microstructural changes at term and early developmental outcomes in infants born very preterm

PURPOSE

Very preterm (VPT) infants are at high risk for motor and behavioral deficits. We investigated microstructural differences using diffusion tensor imaging (DTI) among VPT infants with different grades of intraventricular hemorrhage (IVH), their association with early motor function and temperament ratings, and the potential moderating effect of IVH severity on the above structure-function relations.

METHODS

Fifty-seven VPT (≤32 weeks gestational age) infants with IVH (Low Grade (Papile grading I/II): 42; High Grade (III/IV): 15) were studied. DTI was acquired between 39 and 44 weeks postmenstrual age and was analyzed using the tract-based spatial statistics approach. Early motor function and temperament were assessed at 3-month corrected age based on the Hammersmith Infant Neurological Examination (HINE) and Infant Behavioral Questionnaire - Revised, Short Version (IBQ-R-S), respectively.

RESULTS

Significantly lower fractional anisotropy and higher mean, axial, and/or radial diffusivity were found in VPT infants with High Grade IVH compared to Low Grade IVH (p < 0.05). Significant associations were found between DTI metrics and motor function in both IVH groups and between DTI and Fear temperament ratings in the High Grade IVH Group (all p < 0.05). IVH severity had a significant moderating effect on the relation between DTI and motor and Fear ratings (p < 0.05).

CONCLUSION

DTI is a sensitive neuroimaging biomarker providing a refined understanding of the impact and location of differing severities of IVH on the developing white matter of VPT infants. Early motor and behavioral outcomes are associated with microstructural changes that are influenced by severity of IVH.

White matter injury in infants with intraventricular haemorrhage: mechanisms and therapies

Intraventricular haemorrhage (IVH) continues to be a major complication of prematurity that can result in cerebral palsy and cognitive impairment in survivors. No optimal therapy exists to prevent IVH or to treat its consequences. IVH varies in severity and can present as a bleed confined to the germinal matrix, small-to-large IVH or periventricular haemorrhagic infarction. Moderate-to-severe haemorrhage dilates the ventricle and damages the periventricular white matter. This white matter injury results from a constellation of blood-induced pathological reactions, including oxidative stress, glutamate excitotoxicity, inflammation, perturbed signalling pathways and remodelling of the extracellular matrix. Potential therapies for IVH are currently undergoing investigation in preclinical models and evidence from clinical trials suggests that stem cell treatment and/or endoscopic removal of clots from the cerebral ventricles could transform the outcome of infants with IVH. This Review presents an integrated view of new insights into the mechanisms underlying white matter injury in premature infants with IVH and highlights the importance of early detection of disability and immediate intervention in optimizing the outcomes of IVH survivors.

School-age outcomes following intraventricular haemorrhage in infants born extremely preterm

OBJECTIVE

To determine the associations of different grades of intraventricular haemorrhage (IVH), particularly grades 1 and 2, with neurodevelopmental outcomes at 8 years of age in children born extremely preterm.

DESIGN

Population-based cohort study.

SETTING

State of Victoria, Australia.

PATIENTS

Survivors born at <28 weeks' gestational age (n=546) and matched term-born controls (n=679) from three distinct eras, namely, those born in 1991-1992, 1997 and 2005.

EXPOSURE

Worst grade of IVH detected on serial neonatal cranial ultrasound.

OUTCOME MEASURES

Intellectual ability, executive function, academic skills, cerebral palsy and motor function at 8 years.

RESULTS

There was a trend for increased motor dysfunction with increasing severity of all grades of IVH, from 24% with no IVH, rising to 92% with grade 4 IVH. Children with grade 1 or 2 IVH were at higher risk of developing cerebral palsy than those without IVH (OR 2.24, 95% CI 1.21 to 4.16). Increased rates of impairment in intellectual ability and academic skills were observed with higher grades of IVH, but not for grade 1 and 2 IVH. Parent-rated executive functioning was not related to IVH.

CONCLUSION

While low-grade IVH is generally considered benign, it was associated with higher rates of cerebral palsy in school-aged children born EP, but not with intellectual ability, executive function, academic skills or overall motor function. Higher grades of IVH were associated with higher rates and risks of impairment in motor function, intellectual ability and some academic skills, but not parental ratings of executive function.

The cingulum in very preterm infants relates to language and social-emotional impairment at 2 years of term-equivalent age

•

Maturation of specific WM tracts in preterm individuals differs from those of term controls.

•

The elastic net logistic regression model was used to identify altered white matter tracts in the preterm brain.

•

The alteration of the cingulum in the preterm at near-term correlate with neurodevelopmental scores at 18–22 months of age.

Background

Relative to full-term infants, very preterm infants exhibit disrupted white matter (WM) maturation and problems related to development, including motor, cognitive, social-emotional, and receptive and expressive language processing.

Objective

The present study aimed to determine whether regional abnormalities in the WM microstructure of very preterm infants, as defined relative to those of full-term infants at a near-term age, are associated with neurodevelopmental outcomes at the age of 18–22 months.

Methods

We prospectively enrolled 89 very preterm infants (birth weight < 1500 g) and 43 normal full-term control infants born between 2016 and 2018. All infants underwent a structural brain magnetic resonance imaging scan at near-term age. The diffusion tensor imaging (DTI) metrics of the whole-brain WM tracts were extracted based on the neonatal probabilistic WM pathway. The elastic net logistic regression model was used to identify altered WM tracts in the preterm brain. We evaluated the associations between the altered WM microstructure at near-term age and motor, cognitive, social-emotional, and receptive and expressive language developments at 18–22 months of age, as measured using the Bayley Scales of Infant Development, Third Edition.

Results

We found that the elastic net logistic regression model could classify preterm and full-term neonates with an accuracy of 87.9% (corrected p < 0.008) using the DTI metrics in the pathway of interest with a 10% threshold level. The fractional anisotropy (FA) values of the body and splenium of the corpus callosum, middle cerebellar peduncle, left and right uncinate fasciculi, and right portion of the pathway between the premotor and primary motor cortices (premotor-PMC), as well as the mean axial diffusivity (AD) values of the left cingulum, were identified as contributive features for classification. Increased adjusted AD values in the left cingulum pathway were significantly correlated with language scores after false discovery rate (FDR) correction (r = 0.217, p = 0.043). The expressive language and social-emotional composite scores showed a significant positive correlation with the AD values in the left cingulum pathway (r = 0.226 [p = 0.036] and r = 0.31 [p = 0.003], respectively) after FDR correction.

Conclusion

Our approach suggests that the cingulum pathways of very preterm infants differ from those of full-term infants and significantly contribute to the prediction of the subsequent development of the language and social-emotional domains. This finding could improve our understanding of how specific neural substrates influence neurodevelopment at later ages, and individual risk prediction, thus helping to inform early intervention strategies that address developmental delay.

Reduced fractional anisotropy in projection, association, and commissural fiber networks in neonates with prenatal methamphetamine exposure

Prenatal exposure to methamphetamine is associated with neurostructural changes, including alterations in white matter microstructure. This study investigated the effects of methamphetamine exposure on microstructure of global white matter networks in neonates. Pregnant women were interviewed beginning in mid-pregnancy regarding their methamphetamine use. Diffusion weighted imaging sets were acquired for 23 non-sedated neonates. White matter bundles associated with pairs of target regions within five networks (commissural fibers, left and right projection fibers, and left and right association fibers) were estimated using probabilistic tractography, and fractional anisotropy (FA) and diffusion measures determined within each connection. Multiple regression analyses showed that increasing methamphetamine exposure was significantly associated with reduced FA in all five networks, after control for potential confounders. Increased exposure was associated with lower axial diffusivity in the right association fiber network and with increased radial diffusivity in the right projection and left and right association fiber networks. Within the projection and association networks a subset of individual connections showed a negative correlation between FA and methamphetamine exposure. These findings are consistent with previous reports in older children and demonstrate that microstructural changes associated with methamphetamine exposure are already detectable in neonates.

Intraventricular hemorrhage in preterm babies

Germinal matrix-intraventricular hemorrhage (GM-IVH) is a major complication of prematurity and inversely associated with gestational age and birth weight. The hemorrhage originates from the germinal matrix with an immature capillary bed where vascularization is intense and active cell proliferation is high. It occurs in around 20% of very low-birth-weight preterm neonates. Germinal matrix-intraventricular hemorrhage is less common in females, the black race, and with antenatal steroid use, but is more common in the presence of mechanical ventilation, respiratory distress, pulmonary bleeding, pneumothorax, chorioamnionitis, asphyxia, and sepsis. Ultrasonography is the diagnostic tool of choice for intraventricular hemorrhage and its complications. Approximately 25-50% of the germinal matrix-intraventricular hemorrhage cases are asymptomatic and diagnosed during routine screening. These cases are usually patients with low-grade hemorrhage. Neurologic findings are prominent in severe intraventricular hemorrhage cases. The major complications of the germinal matrix-intraventricular hemorrhage in preterm babies are periventricular hemorrhagic infarction, posthemorrhagic ventricular dilatation, periventricular leukomalacia, and cerebellar hemorrhage. It is an important cause of mortality and morbidity. The management of hemodynamics and ventilation of patients, appropriate follow-up, and early diagnosis and treatment can minimize morbidity. Prognosis in intraventricular hemorrhage is related to the severity of bleeding, parenchymal damage, and the presence of seizures and shunt surgery. The main determinant of prognosis is periventricular hemorrhagic infarction and its severity. Moderate-severe intraventricular hemorrhage can cause posthemorrhagic hydrocephalus, cerebral palsy, and mental retardation. Even mild germinal matrix-intraventricular hemorrhage can result in developmental disorders. Long-term problems such as neurodevelopmental disorders and cerebral palsy are as important as short-term problems. Improving the quality of life of these babies should be aimed through appropriate treatment and follow-up. In this review, intraventricular hemorrhage and complications are discussed.

Feed-forward neural networks using cerebral MR spectroscopy and DTI might predict neurodevelopmental outcome in preterm neonates

Objectives

We aimed to evaluate the ability of feed-forward neural networks (fNNs) to predict the neurodevelopmental outcome (NDO) of very preterm neonates (VPIs) at 12 months corrected age by using biomarkers of cerebral MR proton spectroscopy (¹H-MRS) and diffusion tensor imaging (DTI) at term-equivalent age (TEA).

Methods

In this prospective study, 300 VPIs born before 32 gestational weeks received an MRI scan at TEA between September 2013 and December 2017. Due to missing or poor-quality spectroscopy data and missing neurodevelopmental tests, 173 VPIs were excluded. Data sets consisting of 103 and 115 VPIs were considered for prediction of motor and cognitive developmental delay, respectively. Five metabolite ratios and two DTI characteristics in six different areas of the brain were evaluated. A feature selection algorithm was developed for receiving a subset of characteristics prevalent for the VPIs with a developmental delay. Finally, the predictors were constructed employing multiple fNNs and fourfold cross-validation.

Results

By employing the constructed fNN predictors, we were able to predict cognitive delays of VPIs with 85.7% sensitivity, 100% specificity, 100% positive predictive value (PPV) and 99.1% negative predictive value (NPV). For the prediction of motor delay, we achieved a sensitivity of 76.9%, a specificity of 98.9%, a PPV of 90.9% and an NPV of 96.7%.

Conclusion

FNNs might be able to predict motor and cognitive development of VPIs at 12 months corrected age when employing biomarkers of cerebral ¹H-MRS and DTI quantified at TEA.

Key Points

• A feed-forward neuronal network is a promising tool for outcome prediction in premature infants.

• Cerebral proton magnetic resonance spectroscopy and diffusion tensor imaging can be used for the construction of early prognostic biomarkers.

• Premature infants that would most benefit from early intervention services can be spotted at the time of optimal neuroplasticity.

Electronic supplementary material

The online version of this article (10.1007/s00330-020-07053-8) contains supplementary material, which is available to authorized users.

Cerebral palsy after very preterm birth - an imaging perspective

Neonatal brain imaging undoubtedly can provide the most accurate information from which to determine whether cerebral palsy is likely to affect an individual infant born preterm. The sensitivity and specificity of that information is different between cranial ultrasound and MRI, depending on what approaches and sequences are used and the timing of the examinations. In this chapter we highlight the changing incidence of different patterns of brain injury in the preterm newborn and present a comparison of cranial ultrasound and MRI for predicting cerebral palsy in preterm infants affected by the commoner intracranial pathologies.

Altered structural brain networks at term-equivalent age in preterm infants with grade 1 intraventricular hemorrhage

BACKGROUND

Preterm infants are at risk for structural disruption of brain connectivity due to perinatal complications encountered during the fetal and neonatal periods. This study aimed to investigate the development of connectivity using diffusion tensor imaging at near-term age and the effect of grade 1 intraventricular hemorrhage on it.

METHODS

A total of 86 infants (55 preterm infants, 24 full-term infants) without apparent brain injury underwent diffusion magnetic resonance imaging (MRI) between 36 and 41 weeks post-menstrual age. The diffusion-MRI based connectomics were constructed from 64-segmented regions by using the Johns Hopkins University neonate atlas and were weighted with fractional anisotropy. The connectomes were quantified in the structural networks and investigated using network metrics, such as the clustering coefficient, local efficiency, characteristic path length, global efficiency, and small-worldness. We compared the differences in the brain networks of preterm infants with or without grade 1 intraventricular hemorrhage in binary and fractional anisotropy-weighted (wFA) connectomes.

RESULTS

The 55 preterm infants had a mean gestational age at birth of 29.3 ± 4.1 weeks and the 24 term-born infants, 38.1 ± 1.1 weeks. A total of 13 of the 55 preterm infants (23.6%) were diagnosed with grade 1 intraventricular hemorrhage. The development of connectivity of the brain network in preterm infants without intraventricular hemorrhage was comparable at near-term age to that in term infants. The preterm infants with germinal matrix hemorrhage exhibited higher clustering (0.093 ± 0.015 vs. 0.088 ± 0.007, p = 0.027) and local efficiency (0.151 ± 0.022 vs. 0.141 ± 0.010, p = 0.025), implying the potential for segregation. However, the preterm infants with intraventricular hemorrhage revealed a longer path length (0.291 ± 0.035 vs. 0.275 ± 0.019, p = 0.020) and lower global efficiency (3.998 ± 0.473 vs. 4.212 ± 0.281, p = 0.048), indicating a decreased integration in the wFA connectivity matrix than those without germinal matrix hemorrhage, after correcting for gestational age, sex, bronchopulmonary dysplasia, and age at scan.

CONCLUSION

Grade 1 intraventricular hemorrhage in preterm infants may enhance the capacity for local information transfer and the relative reinforcement of the segregation of networks at the expense of global integration capacity.

Is Low-Grade Intraventricular Hemorrhage in Very Preterm Infants an Innocent Condition? Structural and Functional Evaluation of the Brain Reveals Regional Neurodevelopmental Abnormalities

BACKGROUND AND PURPOSE

There is increasing evidence of abnormal neurodevelopmental outcomes in very preterm infants with low-grade intraventricular hemorrhage grades I and II. Our purpose was to evaluate the effects of low-grade intraventricular hemorrhage on gray and white matter integrity.

MATERIALS AND METHODS

MR imaging at around term-equivalent age was performed in 16 very preterm infants (mean gestational age, 28.8 ± 5.3 weeks) with mild intraventricular hemorrhage on brain sonography and 13 control subjects (mean gestational age, 29.6 ± 4.1 weeks) without intraventricular hemorrhage. Structural and functional evaluation of the cortex was performed using regional measurements of surface area, thickness and volume, and resting-state fMRI, respectively, and of WM microstructural integrity, applying Tract-Based Spatial Statistics to diffusion tensor imaging data.

RESULTS

Compared with the control infants, the infants with low-grade intraventricular hemorrhage had decreases in the following: 1) GM surface area in Brodmann areas 19 left and 9 and 45 right, and GM volume in Brodmann areas 9 and 10 right; 2) fractional anisotropy bilaterally in major WM tracts; and 3) brain activity in the left lower lateral and in the right higher medial somatosensory cortex.

CONCLUSIONS

Very premature infants with low-grade intraventricular hemorrhage at around term-equivalent age may present with regional abnormalities, appearing on imaging studies as cortical underdevelopment, functional impairment, and microstructural immaturity of major WM tracts.

Randomized Control Trial of Postnatal rhIGF-1/rhIGFBP-3 Replacement in Preterm Infants: Post-hoc Analysis of Its Effect on Brain Injury

Background: Postnatal insulin-like growth factor-1 (IGF-1) replacement with recombinant human (rh)IGF-1 and IGF binding protein-3 (rhIGF-1/rhIGFBP-3) is being studied as a potential treatment to reduce comorbidities of prematurity. We have recently reported on a phase II, multicenter, randomized, controlled trial comparing postnatal rhIGF-1/rhIGFBP-3 replacement with standard of care (SOC) in extremely preterm infants (NCT01096784). Maximum severity of retinopathy of prematurity was the primary endpoint of the trial and presence of GMH-IVH/PHI one of the pre-specified secondary endpoints. Infants therefore received serial cranial ultrasound scans (CUS) between birth and term age. In this post-hoc analysis we present a detailed analysis of the CUS data of this trial and evaluate the effect of postnatal rhIGF-1/rhIGFBP-3 replacement on the incidence of different kinds of brain injury in extremely preterm infants. Methods: This report is an exploratory post-hoc analysis of a phase II trial in which infants <28 weeks gestational age were randomly allocated to rhIGF-1/rhIGFBP-3 or SOC. Serial cranial ultrasounds were performed between birth and term-equivalent age. Presence of germinal matrix hemorrhage and intraventricular hemorrhage (GMH-IVH), periventricular hemorrhagic infarction (PHI), post-hemorrhagic ventricular dilatation, and white matter injury (WMI) were scored by two independent masked readers. Results: The analysis included 117 infants; 58 received rhIGF-1/rhIGFBP-3 and 59 received SOC. A trend toward less grade II-III GMH-IVH and PHI was observed in treated infants vs. SOC. A subanalysis of infants without evidence of GMH-IVH at study entry (n = 104) showed reduced progression to GMH-IVH in treated infants (25.0% [13/52] vs. 40.4% [21/52]; not significant). No effects of rhIGF-1/rhIGFBP-3 on WMI were observed. Conclusion: The potential protective effect of rhIGF-1/rhIGFBP-3 on the occurrence of GMH-IVH/PHI appeared most pronounced in infants with no evidence of GMH-IVH at treatment start.

Punctate white matter lesions of preterm infants: Risk factor analysis

AIM

Punctate white matter lesions (PWML) are frequently detected in preterm infants undergoing brain MRI at term equivalent age (TEA). The aims of this study were to assess prevalence of PWML and to identify risk factors for PWML in VLBW infants.

METHODS

Brain MRI scans obtained at TEA and clinical charts of a consecutive sample of very low birth weight (VLBW) infants admitted to Gaslini Children's Hospital NICU between 2012 and 2016 were retrospectively analyzed. MRI protocol included Susceptibility Weighted Imaging (SWI) sequence in order to identify hemosiderin depositions as a result of previous microbleeds. PWML were classified according to their number (≤6 lesions and >6 lesions) and signal characteristics (SWI+ lesions and SWI- lesions). Univariate and multivariable analysis were performed in order to identify risk factors for PWML (as a whole) and for each subgroup of PWML.

RESULTS

321 VLBW infants were included. PWML were identified in 61 subjects (19%), 26 of whom (8% of the study population) had more than 6 lesions. Risk factors for PWML (as a whole) were higher birth weight (OR = 1.001; p = 0.04) and absent or incomplete antenatal steroid course (OR = 2.13; p = 0.02). Risk factors for >6 PWML were need for intubation (OR = 11.9; p = 0.003) and higher Apgar score at 5 min (OR = 1.8; p = 0.02). Presence of GMH-IVH was the only identified risk factor for SWI + lesions.

CONCLUSIONS

Our results confirm the high prevalence of PWML among VLBW infants. Differentiation between SWI+ and SWI- lesions is crucial as they have different risk factors and may likely represent two different entities.

Early Pain Exposure Influences Functional Brain Connectivity in Very Preterm Neonates

Background

Early exposure to nociceptive events may cause brain structural alterations in preterm neonates, with long-lasting consequences on neurodevelopmental outcome. Little is known on the extent to which early pain may affect brain connectivity. We aim to evaluate brain functional connectivity changes in preterm neonate that underwent multiple invasive procedures during the postnatal period, and to correlate them with the neurodevelopmental outcome at 24 months.

Methods

In this prospective case-control study, we collected information about exposure to painful events during the early postnatal period and resting-state BOLD-fMRI data at term equivalent age from two groups of preterm neonate: 33 subjected to painful procedures during the neonatal intensive care (mean gestational age 27.9 ± 1.8 weeks) and 13 who did not require invasive procedures (average gestational age 31.2 ± 2.1 weeks). A data-driven principal-component-based multivariate pattern analysis (MVPA) was used to investigate the effect of early pain exposure on brain functional connectivity, and the relationship between connectivity changes and neurodevelopmental outcome at 24 months, assessed with Griffiths, Developmental Scale-Revised: 0-2.

Results

Early pain was associated with decreased functional connectivity between thalami and bilateral somatosensory cortex, and between the right insular cortex and ipsilateral amygdala and hippocampal regions, with a more evident effect in preterm neonate undergoing more invasive procedures. Functional connectivity of the right thalamocortical pathway was related to neuromotor outcome at 24 months (P = 0.003).

Conclusion

Early exposure to pain is associated with abnormal functional connectivity of developing networks involved in the modulation of noxious stimuli in preterm neonate, contributing to the neurodevelopmental consequence of preterm birth.

Low-grade intraventricular hemorrhage of preterm infants: neurodevelopmental and motor outcome

Intraventricular hemorrhage (IVH) is a main complication of prematurity, inversely associated with gestational age and birth weight. Low-grade IVH (I and II), diagnosed by cranial ultrasound, had long been considered rather not to affect neurodevelopmental and motor outcome, a view challenged by several literature reports. However, diversity in studies design, periods of subjects' collection, cohort characteristics, demographic data, maternal or neonatal comorbidities, neuroimaging methods, evaluation tools, short-or-long-term follow-up by the same or different examiners, as well as other parameters and confounders make comparisons among reports very difficult, not allowing solid conclusions. Older, but also newer investigations claim both possible outcomes: impairment or not of cognitive and motor abilities in very preterm infants with low-grade IVH. Thus, the current suggestion in the relevant literature is not to rely only on the results of cranial ultrasounds, but to also implement classic, or even more advanced MRI techniques at term equivalent age to preterm infants with grade I or II IVH. In addition, the continuation of close follow-up during school age is warranted.

Pattern of intracranial findings detected on magnetic resonance imaging in surviving infants born before 29 weeks of gestation

Despite the positive survival trend in infants born prematurely, the risk for development of intracranial lesions has remained unchanged. However, there are limitations to our understanding of the pattern of the magnetic resonance imaging (MRI) -detected brain pathology in the preterm infants surviving to discharge. The present study outlines the type of intracranial lesions and factors allied with the neonatal brain hemorrhage (NBH) and white matter injury (WMI) seen on MRI at term-equivalent age or close to discharge in infants born before 29 weeks of gestation. We obtained demographic and clinical data, and reports of serial cranial ultrasound (CUS) performed during first month of life and qualitative MRI at term-equivalent age or close to discharge. Statistical comparison was conducted with respect to the MRI results that were classified as normal, WMI, and NBH using univariate and logistic regression analysis. One hundred and ninety three infants with MRI at term-equivalent age or close to discharge were included in final analysis. They were less mature and had a higher prevalence of pathological findings on CUS as compared with 249 other survivors born with gestational ages less than 29 weeks during the assigned study period. MRI was normal in 72.5% [95% Confidence Interval (95% CI 65.9%-78.4%)], showed WMI in 9.8% (95%CI 6.4%-14.9%) and NBH in 17.6% (95%CI 12.9–23.6) of the studied infants. Intracranial hemorrhages had also been reported in 42.2% of the infants with WMI. Except for moderate agreement with prior CUS results, no other factors were associated with the MRI detected pathological findings. In general, the likelihood for detection of WMI and NBH on MRI at term-equivalent age or close to discharge was reduced by approximately 80% and 70%, respectively if the serial CUS had not shown any abnormalities during the first month of life.

Quantitative susceptibility map analysis in preterm neonates with germinal matrix-intraventricular hemorrhage

BACKGROUND

Germinal matrix-intraventricular hemorrhage (GMH-IVH) is a common form of intracranial hemorrhage occurring in preterm neonates that may affect normal brain development. Although the primary lesion is easily identified on MRI by the presence of blood products, its exact extent may not be recognizable with conventional sequences. Quantitative susceptibility mapping (QSM) quantify the spatial distribution of magnetic susceptibility within biological tissues, including blood degradation products.

PURPOSE/HYPOTHESIS

To evaluate magnetic susceptibility of normal-appearing white (WM) and gray matter regions in preterm neonates with and without GMH-IVH.

STUDY TYPE

Retrospective case-control.

POPULATION

A total of 127 preterm neonates studied at term equivalent age: 20 had mild GMH-IVH (average gestational age 28.7 ± 2.1 weeks), 15 had severe GMH-IVH (average gestational age 29.3 ± 1.8 weeks), and 92 had normal brain MRI (average gestational age 29.8 ± 1.8 weeks).

FIELD STRENGTH/SEQUENCE

QSM at 1.5 Tesla.

ASSESSMENT

QSM analysis was performed for each brain hemisphere with a region of interest-based approach including five WM regions (centrum semiovale, frontal, parietal, temporal, and cerebellum), and a subcortical gray matter region (basal ganglia/thalami).

STATISTICAL TESTS

Changes in magnetic susceptibility were explored using a one-way analysis of covariance, according to GMH-IVH severity (P < 0.05).

RESULTS

In preterm neonates with normal brain MRI, all white and subcortical gray matter regions had negative magnetic susceptibility values (diamagnetic). Neonates with severe GMH-IVH showed higher positive magnetic susceptibility values (i.e. paramagnetic) in the centrum semiovale (0.0019 versus -0.0014 ppm; P < 0.001), temporal WM (0.0011 versus -0.0012 ppm; P = 0.037), and parietal WM (0.0005 versus -0.0001 ppm; P = 0.002) compared with controls. No differences in magnetic susceptibility were observed between neonates with mild GMH-IVH and controls (P = 0.236).

DATA CONCLUSION

Paramagnetic susceptibility changes occur in several normal-appearing WM regions of neonates with severe GMH-IVH, likely related to the accumulation of hemosiderin/ferritin iron secondary to diffusion of extracellular hemoglobin from the ventricle into the periventricular WM.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1199-1207.