Incidence of brain lesions in moderate-late preterm infants assessed by cranial ultrasound and MRI: The BIMP-study

Incidence and Risk Factors of White Matter Lesions in Moderate and Late Preterm Infants

Background: Moderate and late preterm infants (32-36 weeks of gestation) are at significant risk of developmental impairments. Incidence of white matter lesions, which are associated with developmental impairments in very preterm infants, remains underreported in this population. This study aimed to assess the incidence and clinical risk factors associated with brain lesions, particularly white matter lesions, in moderate and late preterm infants using term-equivalent MRI. Methods: This prospective observational study included 195 preterm infants born at 32+0-36+6 weeks of gestation and admitted to a tertiary NICU between 2019 and 2020. MRI findings at term-equivalent age were evaluated. Clinical risk factors were analysed using logistic regression. Results: Among the 195 infants, 23.6% had brain lesions on MRI, with white matter lesions (73.9%), specifically punctate white matter lesions, being the most common form of lesions. Vaginal delivery (odds ratio (OR) = 3.102, 95% confidence interval (CI) = 1.250-7.696, p = 0.015), larger birth weight z-scores (OR = 1.702, 95% CI = 1.118-2.591, p = 0.013), and intubation (OR = 2.948, 95% CI = 1.269-6.850, p = 0.012) were significant risk factors for white matter lesions. Conclusions: White matter lesions, particularly punctate white matter lesions, are common in moderate and late preterm infants. These lesions are associated with perinatal factors suggestive of delayed transition and inflammation. Future research should focus on detailed clinical care measures and neurodevelopmental assessments to identify modifiable risk factors for brain injury.

Head Ultrasound Findings in Infants with Birth Weight >1,500 g and Gestational Age >32 Weeks Exposed to Prenatal Opioids

This study aimed to evaluate the effects of prenatal exposure to opioids on head ultrasound (HUS) and to determine the need for routine HUS evaluation in infants exposed to prenatal opioids.This is a retrospective cohort study performed at a level III NICU. Infants >32 weeks gestational age and >1,500 g birth weight with prenatal opioid exposure (n = 127) were included in this study. Data including demographic information and HUS results were recorded.Twenty (16%) infants were exposed to opioids only whereas the rest of the infants (84%) were exposed to opioids plus other drugs (polysubstance) in utero. Sixteen of 127 infants (13%) had abnormal initial HUS. Sub-ependymal hemorrhage or grade 1 intraventricular hemorrhage was the most common abnormal finding. Absent septum pellucidum was seen in three infants.A relatively large proportion (13%) of infants in this study had abnormal HUS findings; however, further studies are required to correlate HUS findings with a specific drug of exposure, duration of exposure, polysubstance use, umbilical cord drug concentration levels, and neurodevelopmental outcomes. · Limited data exists regarding HUS findings in infants with prenatal opioid exposure.. · A relatively large proportion of infants exposed to opioids in utero had abnormal HUS.. · Subependymal hemorrhages or grade I intraventricular hemorrhage was the most common abnormal finding..

Writhing Movements and Hypoglycemia in Moderate-Late Preterm Infants: A Prospective Cohort Study

Introduction: This study aims to examine the relationship between hypoglycemia and general movement patterns during the early post-term-aged in moderate-to-late preterm infants and to assess the interobserver reliability of movement evaluation during this period. Compared with full-term infants, moderate-to-late preterm infants constitute the largest group of premature births globally and are at greater risk of developing neurodevelopmental disorders. Hypoglycemia is one of the most prevalent risk factors in this group. Methods: This prospective single-center explorative cohort study included moderate-to-late preterm infants during their admission in the neonatal intensive care unit. General movements were assessed via Prechtl's General Movements Assessment, and blood glucose levels were monitored via the FreeStyle Optium™ Neo glucometer. Associations were analyzed via Fisher's exact test, whereas interobserver reliability was evaluated via the intraclass correlation coefficient (ICC) and the kappa coefficient. Results: A total of 17 moderate-to-late preterm infants with hypoglycemia (<45 mg/dL) presented a relatively high percentage (58.8%) of poor repertoire and normal (35.2%) general movement patterns during the early post-term-aged. Interobserver reliability was good (ICC = 0.7), and the kappa coefficient indicated moderate reliability (0.4). Conclusions: Moderate-to-late preterm infants with transient hypoglycemia may frequently display poor repertoire movement patterns, highlighting the need for careful monitoring. Furthermore, the evaluation of general movements proves to be a reliable tool during the early post-term-aged.

Neurocognitive outcomes in moderately preterm born adolescents

BACKGROUND

Early preterm (EP) born children are at risk of neurocognitive impairments persisting into adulthood. Less is known about moderately to late (MLP) preterm born children, especially after early childhood. The aim of this study was to assess neurocognitive functioning of MLP adolescents regarding intelligence, executive and attentional functioning, compared with EP and full-term (FT) adolescents.

METHODS

This study was part of the Longitudinal Preterm Outcome Project (LOLLIPOP), a large community-based observational cohort study. In total 294 children (81 EP, 130 MLP, and 83 FT) were tested at age 14 to 16 years, regarding intelligence, speed of processing, attention, and executive functions. We used the Dutch version of the Wechsler Intelligence Scale for Children-Third Edition-Dutch Version (WISC-III-NL), the Test of Everyday Attention for Children, and the Behavioural Assessment of the Dysexecutive Syndrome for Children. We assessed differences between preterm-born groups with the FT group as a reference.

RESULTS

Compared to the FT group, MLP adolescents scored significantly lower on two subtasks of the WISC-III-NL, i.e. Similarities and Symbol Search. EP adolescents performed significantly lower on all neuropsychological tests than their FT peers, except for the subtask Vocabulary. The MLP adolescents scored in between FT and EP adolescents on all tasks, except for three WISC-III-NL subtasks.

CONCLUSIONS

Neurocognitive outcomes of MLP adolescents fell mostly in between outcomes of their EP and FT peers. MLPs generally performed on a low-average to average level, and appeared susceptible to a variety of moderate neurodevelopmental problems at adolescent age, which deserves attention in clinical practice.

Listening Preference for Child-Directed Speech Versus Time-Reversed Speech in Moderate-Preterm Infants Compared to Full-Term Infants

PURPOSE

The purpose of the present study was to examine whether there is a listening preference for child-directed speech (CDS) over backward speech in moderate-preterm infants (MPIs).

METHOD

Eighteen MPIs of gestational age of 32.0 weeks (range: 32-34.06 weeks), chronological age of 8.09 months, and maturation age of 6.48 months served as the experimental group. The two control groups consisted of a total of 36 infants-20 full-term infants matched for chronological age and 16 full-term infants matched for maturation age. The infants were tested using the central fixation procedure and were presented with 16 trials of CDS and backward speech. A follow-up was conducted 5 years after the initial experiment using a developmental and a five-item parent questionnaire.

RESULTS

MPIs did not demonstrate a preference for CDS over backward speech, whereas both control groups demonstrated a listening preference for CDS over backward speech. MPIs showed a delayed use of first words and word combinations and lower scores on the five-item questionnaire compared to term infants. Twelve MPIs (67%) did not demonstrate a preference for CDS over backward speech. Four of them (33%) were later diagnosed with neurodevelopmental disorders.

CONCLUSIONS

The lack of preference for CDS over backward speech in the MPIs group suggests delayed developmental pattern of speech processing compared to full-term peers. Delays in neurological maturation as well as listening experience in an unregulated environment outside the uterus during a sensitive period of brain development may affect the recognition of phonological and prosodic patterns that support listening preference for speech over backward speech.

Neurodevelopmental outcome of low-risk moderate to late preterm infants at 18 months

Background

Of the 15 million preterm births that occur worldwide each year, approximately 80% occur between 32 and 36 + 6 weeks gestational age (GA) and are defined as moderate to late preterm (MLP) infants. This percentage substantiates a need for a better understanding of the neurodevelopmental outcome of this group.

Aim

To describe neurodevelopmental outcome at 18 months in a cohort of healthy low-risk MLP infants admitted to the neonatal unit at birth and to compare the neurodevelopmental outcome to that of a healthy term-born infant group.

Study design and method

This single-centre observational study compared the neurodevelopmental outcome of healthy MLP infants to a group of healthy term control (TC) infants recruited during the same period using the Griffith's III assessment at 18 months.

Results

Seventy-five MLP infants and 92 TC infants were included. MLP infants scored significantly lower in the subscales: Eye-hand coordination (C), Personal, Social and Emotional Development (D), Gross Motor Development (E) and General Developmental (GD) (p < 0.001 for each) and Foundations of Learning (A), (p = 0.004) in comparison to the TC infant group with Cohen's d effect sizes ranging from 0.460 to 0.665. There was no statistically significant difference in mean scores achieved in subscale B: Language and Communication between groups (p = 0.107).

Conclusion

MLP infants are at risk of suboptimal neurodevelopmental outcomes. Greater surveillance of the neurodevelopmental trajectory of this group of at-risk preterm infants is required.

Cranial Ultrasound Abnormalities in Small for Gestational Age or Growth-Restricted Infants Born over 32 Weeks Gestation: A Systematic Review and Meta-Analysis

AIM

To perform a systematic review and meta-analysis of existing literature to evaluate the incidence of cranial ultrasound abnormalities (CUAs) amongst moderate to late preterm (MLPT) and term infants, affected by fetal growth restriction (FGR) or those classified as small for gestational age (SGA).

METHODS

A systematic review methodology was performed, and Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) statement was utilised. Descriptive and observational studies reporting cranial ultrasound outcomes on FGR/SGA MLPT and term infants were included. Primary outcomes reported was incidence of CUAs in MLPT and term infants affected by FGR or SGA, with secondary outcomes including brain structure development and growth, and cerebral artery Dopplers. A random-effects model meta-analysis was performed. Risk of Bias was assessed using the Newcastle-Ottawa scale for case-control and cohort studies, and Joanna Briggs Institute Critical Appraisal Checklist for studies reporting prevalence data. GRADE was used to assess for certainty of evidence.

RESULTS

Out of a total of 2085 studies identified through the search, seventeen were deemed to be relevant and included. Nine studies assessed CUAs in MLPT FGR/SGA infants, seven studies assessed CUAs in late preterm and term FGR/SGA infants, and one study assessed CUAs in both MLPT and term FGR/SGA infants. The incidence of CUAs in MLPT, and late preterm to term FGR/SGA infants ranged from 0.4 to 33% and 0 to 70%, respectively. A meta-analysis of 7 studies involving 168,136 infants showed an increased risk of any CUA in FGR infants compared to appropriate for gestational age (AGA) infants (RR 1.96, [95% CI 1.26-3.04], I² = 68%). The certainty of evidence was very low due to non-randomised studies, methodological limitations, and heterogeneity. Another meta-analysis looking at 4 studies with 167,060 infants showed an increased risk of intraventricular haemorrhage in FGR/SGA infants compared to AGA infants (RR 2.40, [95% CI 2.03-2.84], I² = 0%). This was also of low certainty.

CONCLUSIONS

The incidence of CUAs in MLPT and term growth-restricted infants varied widely between studies. Findings from the meta-analyses suggest the risk of CUAs and IVH may indeed be increased in these FGR/SGA infants when compared with infants not affected by FGR, however the evidence is of low to very low certainty. Further specific cohort studies are needed to fully evaluate the benefits and prognostic value of cranial ultrasonography to ascertain the need for, and timing of a cranial ultrasound screening protocol in this infant population, along with follow-up studies to ascertain the significance of CUAs identified.

Improved neonatal brain MRI segmentation by interpolation of motion corrupted slices

BACKGROUND AND PURPOSE

To apply and evaluate an intensity-based interpolation technique, enabling segmentation of motion-affected neonatal brain MRI.

METHODS

Moderate-late preterm infants were enrolled in a prospective cohort study (Brain Imaging in Moderate-late Preterm infants "BIMP-study") between August 2017 and November 2019. T2-weighted MRI was performed around term equivalent age on a 3T MRI. Scans without motion (n = 27 [24%], control group) and with moderate-severe motion (n = 33 [29%]) were included. Motion-affected slices were re-estimated using intensity-based shape-preserving cubic spline interpolation, and automatically segmented in eight structures. Quality of interpolation and segmentation was visually assessed for errors after interpolation. Reliability was tested using interpolated control group scans (18/54 axial slices). Structural similarity index (SSIM) was used to compare T2-weighted scans, and Sørensen-Dice was used to compare segmentation before and after interpolation. Finally, volumes of brain structures of the control group were used assessing sensitivity (absolute mean fraction difference) and bias (confidence interval of mean difference).

RESULTS

Visually, segmentation of 25 scans (22%) with motion artifacts improved with interpolation, while segmentation of eight scans (7%) with adjacent motion-affected slices did not improve. Average SSIM was .895 and Sørensen-Dice coefficients ranged between .87 and .97. Absolute mean fraction difference was ≤0.17 for less than or equal to five interpolated slices. Confidence intervals revealed a small bias for cortical gray matter (0.14-3.07 cm3 ), cerebrospinal fluid (0.39-1.65 cm3 ), deep gray matter (0.74-1.01 cm3 ), and brainstem volumes (0.07-0.28 cm3 ) and a negative bias in white matter volumes (-4.47 to -1.65 cm3 ).

CONCLUSION

According to qualitative and quantitative assessment, intensity-based interpolation reduced the percentage of discarded scans from 29% to 7%.

Ultrasound measurements of brain structures differ between moderate-late preterm and full-term infants at term equivalent age

BACKGROUND

Brain growth in moderate preterm (MP; gestational age (GA) 32⁺⁰-33⁺⁶ weeks) and late preterm infants (LP; GA 34⁺⁰-36⁺⁶ weeks) may be impaired, even in the absence of brain injury.

AIMS

The aims of this study were to assess brain measurements of MP and LP infants, and to compare these with full-term infants (GA > 37 weeks) using linear cranial ultrasound (cUS) at term equivalent age (TEA).

STUDY DESIGN

cUS data from two prospective cohorts were combined. Two investigators performed offline measurements on standard cUS planes. Eleven brain structures were compared between MP, LP and full-term infants using uni- and multivariable linear regression. Results were adjusted for postmenstrual age at cUS and corrected for multiple testing.

RESULTS

Brain measurements of 44 MP, 54 LP and 52 full-term infants were determined on cUS scans at TEA. Biparietal diameter and basal ganglia-insula width were smaller in MP (-9.1 mm and - 1.7 mm, p < 0.001) and LP infants (-7.0 mm and - 1.7 mm, p < 0.001) compared to full-term infants. Corpus callosum - fastigium length was larger in MP (+2.2 mm, p < 0.001) than in full-term infants. No significant differences were found between MP and LP infants.

CONCLUSIONS

These findings suggest that brain growth in MP and LP infants differs from full-term infants. Whether these differences have clinical implications remains to be investigated.

Mild brain lesions do not affect brain volumes in moderate-late preterm infants

PURPOSE

It is unknown whether frequently occurring mild brain lesions affect brain volumes in moderate (MP²; 32⁺⁰-33⁺⁶ weeks' gestation) and late (LP³; 34⁺⁰-35⁺⁶ weeks' gestation) preterm infants. Therefore, we aimed to investigate the effect of mild brain lesions on brain volumes in moderate-late preterm (MLPT⁴) infants and to compare brain volumes between MP and LP infants.

METHODS

From August 2017 to November 2019, eligible MLPT infants born at Isala Women and Children's Hospital were enrolled in a prospective cohort study (Brain Imaging in Moderate-late Preterm infants 'BIMP-study'). MRI was performed around term equivalent age (TEA⁵). MRI scans were assessed for (mild) brain lesions. T2-weighted images were used for automatic segmentation of eight brain structures. Linear regression analysis was performed to compare absolute and relative brain volumes between infants with and without mild brain lesions and between MP and LP infants.

RESULTS

36 MP and 68 LP infants were included. In infants with mild brain lesions, intracranial volume (B = 27.4 cm³, p = 0.02), cerebrospinal fluid (B = 8.78 cm³, p = 0.01) and cerebellar volumes (B = 1.70 cm³, p = 0.03) were significantly larger compared to infants without mild brain lesions. After correction for weight and postmenstrual age at MRI, these volumes were no longer significantly different. LP infants had larger brain volumes than MP infants, but differences were not significant. Relative brain volumes showed no significant differences in both analyses.

CONCLUSION

Neither having mild brain lesions, nor being born moderate prematurely affected brain volumes at TEA in MLPT infants.