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

Multilabel SegSRGAN-A framework for parcellation and morphometry of preterm brain in MRI

Magnetic resonance imaging (MRI) is a powerful tool for observing and assessing the properties of brain tissue and structures. In particular, in the context of neonatal care, MR images can be used to analyze neurodevelopmental problems that may arise in premature newborns. However, the intrinsic properties of newborn MR images, combined with the high variability of MR acquisition in a clinical setting, result in complex and heterogeneous images. Segmentation methods dedicated to the processing of clinical data are essential for obtaining relevant biomarkers. In this context, the design of quality control protocols for the associated segmentation is a cornerstone for guaranteeing the accuracy and usefulness of these inferred biomarkers. In recent work, we have proposed a new method, SegSRGAN, designed for super-resolution reconstruction and segmentation of specific brain structures. In this article, we first propose an extension of SegSRGAN from binary segmentation to multi-label segmentation, leading then to a partitioning of an MR image into several labels, each corresponding to a specific brain tissue/area. Secondly, we propose a segmentation quality control protocol designed to assess the performance of the proposed method with regard to this specific parcellation task in neonatal MR imaging. In particular, we combine scores derived from expert analysis, morphometric measurements and topological properties of the structures studied. This segmentation quality control can enable clinicians to select reliable segmentations for clinical analysis, starting with correlations between perinatal risk factors, regional volumes and specific dimensions of cognitive development. Based on this protocol, we are investigating the strengths and weaknesses of SegSRGAN and its potential suitability for clinical research in the context of morphometric analysis of brain structure in preterm infants, and to potentially design new biomarkers of neurodevelopment. The proposed study focuses on MR images from the EPIRMEX dataset, collected as part of a national cohort study. In particular, this work represents a first step towards the design of 3-dimensional neonatal brain morphometry based on segmentation. The (free and open-source) code of multilabel SegSRGAN is publicly available at the following URL: https://doi.org/10.5281/zenodo.12659424.

Comparative utility of MRI and EEG for early detection of cortical dysmaturation after postnatal systemic inflammation in the neonatal rat

BACKGROUND

Exposure to postnatal systemic inflammation is associated with increased risk of brain injury in preterm infants, leading to impaired maturation of the cerebral cortex and adverse neurodevelopmental outcomes. However, the optimal method for identifying cortical dysmaturation is unclear. Herein, we compared the utility of electroencephalography (EEG), diffusion tensor imaging (DTI), and neurite orientation dispersion and density imaging (NODDI) at different recovery times after systemic inflammation in newborn rats.

METHODS

Sprague Dawley rat pups of both sexes received single-daily lipopolysaccharide (LPS; 0.3 mg/kg i.p.; n = 51) or saline (n = 55) injections on postnatal days (P)1, 2, and 3. A subset of these animals were implanted with EEG electrodes. Cortical EEG was recorded for 30 min from unanesthetized, unrestrained pups at P7, P14, and P21, and in separate groups, brain tissues were collected at these ages for ex-vivo MRI analysis (9.4 T) and Golgi-Cox staining (to assess neuronal morphology) in the motor cortex.

RESULTS

Postnatal inflammation was associated with reduced cortical pyramidal neuron arborization from P7, P14, and P21. These changes were associated with dysmature EEG features (e.g., persistence of delta waveforms, higher EEG amplitude, reduced spectral edge frequency) at P7 and P14, and higher EEG power in the theta and alpha ranges at P21. By contrast, there were no changes in cortical DTI or NODDI in LPS rats at P7 or P14, while there was an increase in cortical fractional anisotropy (FA) and decrease in orientation dispersion index (ODI) at P21.

CONCLUSIONS

EEG may be useful for identifying the early evolution of impaired cortical development after early life postnatal systemic inflammation, while DTI and NODDI seem to be more suited to assessing established cortical changes.

Global trends in neonatal MRI brain neuroimaging research over the last decade: a bibliometric analysis

Background

Neuroimaging plays a central role in the evaluation, treatment, and prognosis of neonates. In recent years, the exploration of the developing brain has been a major focus of research for researchers and clinicians. In this study, we conducted bibliometric and visualization analyses of the related studies in the field of neonatal magnetic resonance imaging (MRI) brain neuroimaging from the past 10 years, and summarized its research status, hotspots, and frontier development trends.

Methods

The Web of Science core collection database was used as the literature source from which to retrieve the relevant papers and reviews in the field of neonatal MRI brain neuroimaging published in the Science Citation Index-Expanded from 2013 to 2022. VOSviewer and CiteSpace were used to conduct bibliometric and visualization analyses of the annual publication volume, countries, institutions, journals, authors, co-cited literature, and the overall distribution of keywords.

Results

We retrieved 3,568 papers and reviews published from 2013 to 2022. The number of publications increased during this period. The United States (US) and the United Kingdom were the largest contributors, with the US receiving the highest H-index and number of citations. The institutions that published the most were the University of London and Harvard University. The research mainly focused on cerebral cortex, brain tissue, brain structure network, artificial intelligence algorithm, automatic image segmentation, and premature infants.

Conclusions

This study reveals the research status and hotspots of magnetic resonance imaging in the field of neonatal brain neuroimaging in the past decade, which helps researchers to better understand the research status, hotspots, and frontier development trends.

Intervention Bundle for Optimization of Procedural Sedation for Newborns Undergoing Magnetic Resonance Imaging: A Single-Center Quality Improvement Project in Qatar

Introduction

Magnetic resonance imaging (MRI) is a common procedure in tertiary care neonatal intensive care units (NICUs). MRIs aid in detailing structural anatomy and are increasingly utilized for prognostication. Keeping babies calm and motion-free in the MRI suite is challenging, and various approaches have been adopted to obtain the best image quality. We share our experience of intervention bundle for procedural sedation with the novel use of buccal midazolam in our NICU for babies undergoing MRI.

Methods

This single-center quality improvement project comprised two epochs. Epoch 1 from April 2018 to December 2020 provided baseline data regarding sedation use and helped identify causes for suboptimal images and the adverse event rate. Following the implementation of an interventional bundle comprising specific midazolam dose recommendations tailored to background risk factors and streamlining the procedural sedation process, similar comparative data were collected in epoch 2 (May 2021 to December 2022) after a washout period.

Results

Of 424 patients, 238 and 108 had MRI done under either procedural sedation protocol or feed and wrap technique in epoch 1 and 2, respectively. After excluding babies whose MRIs were performed under sedative infusions, 30 (13%) babies had adverse events in epoch 1, while only 8 (7%) events occurred in epoch 2. There was also a 37% improvement in the documentation of procedural sedation between the two epochs.

Conclusion

Procedural sedation with buccal midazolam under neonatologist supervision is safe, efficient, and effective in babies undergoing MRI in this single-center study. More extensive studies may be warranted to assess the suitability of this sedation modality for broader use.

Implementation of the Feed and Swaddle Technique as a Non-Pharmacological Strategy to Conduct Brain Magnetic Resonance Imaging in Very Low Birth Weight Infants

Purpose: Magnetic resonance imaging (MRI) is a useful tool for evaluating brain injury and maturation in preterm infants and often requires sedation to acquire images of sufficient quality. Infant sedation is often associated with adverse events, despite extreme precautions. In this study, the swaddling technique was investigated as an alternative non-pharmacological strategy to obtain brain MRIs of sufficient quality.Methods: We applied the feed and swaddle technique during routine brain MRI as a quality improvement project and compared its morbidity with that of sedation in a historic age-matched group. Seventy-nine very low birth weight infants in the neonatal intensive care unit of Ajou University Hospital (Suwon, Korea) were enrolled. Thirty-two (40.5%) infants were in the feed and swaddling group, and 47 (59.5%) were in the sedation group.Results: The morbidity associated with the cardiopulmonary system (swaddling group vs. sedation group: 53.13% [n=17] vs. 63.83% [n=30], P=0.723) and central nervous system (40.63% [n=13] vs. 29.79% [n=14], P=0.217) were not significantly different between groups. The MRI failure rate was not significantly different (swaddling group vs. sedation group: 12.5% [n=4] vs. 4.3% [n=2], P=0.174). The MRI scanning time was longer in the swaddling group than in the sedation group (76.5±20.3 minutes vs. 61.5±13.6 minutes, P=0.001). Cardiopulmonary adverse events were significantly less common in the swaddling group than in the sedation group (3.13% [n=1] vs. 34.04% [n=16], P=0.002).Conclusion: The success rate of MRI was comparable between the swaddling technique and sedation. Furthermore, despite the drawback of prolonged scan time, cardiopulmonary adverse events are fewer with swaddling than with sedative agents. Therefore, swaddling can be an alternative to sedation or anesthesia when performing neonatal MRI scans.