Gregory Lodygensky

• MD
• Professor (Associate) at Université de Montréal

Recent advances in diffusion models have spurred research into their application for Reconstruction-based unsupervised anomaly detection. However, these methods may struggle with maintaining structural integrity and recovering the anomaly-free content of abnormal regions, especially in multi-class scenarios. Furthermore, diffusion models are inhere...

Unsupervised anomaly detection in brain images is crucial for identifying injuries and pathologies without access to labels. However, the accurate localization of anomalies in medical images remains challenging due to the inherent complexity and variability of brain structures and the scarcity of annotated abnormal data. To address this challenge,...

Lack of standardization and various intrinsic parameters for magnetic resonance (MR) image acquisition results in heterogeneous images across different sites and devices, which adversely affects the generalization of deep neural networks. To alleviate this issue, this work proposes a novel unsupervised harmonization framework that leverages normali...

Soft PEDOT/EG/TA films exhibited a low Young's modulus of ~450 kPa, high adhesion, stretchability of ~90% strain, and outstanding self-healing ability. Epidermal electrodes prepared using these films showed high-quality ECG and EMG signal recordings.

Introduction Chronic progressive neuroinflammation is a hallmark of neurological lysosomal storage diseases, including mucopolysaccharidosis III (MPS III or Sanfilippo disease). Since neuroinflammation is linked to white matter tract pathology, we analyzed axonal myelination and white matter density in the mouse model of MPS IIIC HgsnatP304L and po...

Background Perinatal infection/inflammation is associated with a high risk for neurological injury and neurodevelopmental impairment after birth. Despite a growing preclinical evidence base, anti-inflammatory interventions have not been established in clinical practice, partly because of the range of potential targets. We therefore systematically r...

Soft and conductive materials are highly desirable for wearable electronics. In particular, anti‐freezing, long‐water retention, and highly conductive gels with Young's modulus matching that of biological tissues, show promise in bioelectronics. Herein, soft organohydrogels obtained by mixing poly (3,4‐ethylenedioxythiophene) doped with polystyrene...

Neonatal MRIs are used increasingly in preterm infants. However, it is not always feasible to analyze this data. Having a tool that assesses brain maturation during this period of extraordinary changes would be immensely helpful. Approaches based on deep learning approaches could solve this task since, once properly trained and validated, they can...

In this paper, we propose an unsupervised framework based on normalizing flows that harmonizes MR images to mimic the distribution of the source domain. The proposed framework consists of three steps. First, a shallow harmonizer network is trained to recover images of the source domain from their augmented versions. A normalizing flow network is th...

Neurodegeneration and chronic progressive neuroinflammation are well-documented in neurological lysosomal storage diseases, including Sanfilippo disease or mucopolysaccharidosis III (MPS III). Since chronic neuroinflammation has been linked to white matter tract pathology and defects in axonal transmission, we analysed axonal myelination and white...

In this paper, we propose an unsupervised framework based on normalizing flows that harmonizes MR images to mimic the distribution of the source domain. The proposed framework consists of three steps. First, a shallow harmonizer network is trained to recover images of the source domain from their augmented versions. A normalizing flow network is th...

Estimating the prediction uncertainty of a deep segmentation network is very useful in multiple learning scenarios. For example, in the semi-supervised learning paradigm, the vast majority of recent methods rely on pseudo-label generation to leverage unlabeled data, whose training is guided by uncertainty estimates. While the commonly-used entropy-...

Cannabis is one of the most widely used illicit drugs during pregnancy and lactation. With the recent legalization of cannabis in many countries, health professionals are increasingly exposed to pregnant and breastfeeding women who are consuming cannabis on a regular basis as a solution for depression, anxiety, nausea, and pain. Cannabis consumptio...

Background: Therapeutic hypothermia (TH) without sedation may lead to discomfort, which may be associated with adverse consequences in neonates with hypoxic-ischemic encephalopathy (HIE). The aim of this study was to assess the association between level of exposure to opioids and temperature, with electroencephalography (EEG) background activity p...

Resting state functional MRI (rsfMRI) has been shown to be a promising tool to study intrinsic brain functional connectivity and assess its integrity in cerebral development. In neonates, where functional MRI is limited to very few paradigms, rsfMRI was shown to be a relevant tool to explore regional interactions of brain networks. However, to iden...

Background: While seizures have adverse neurological effects, the prescribed antiseizure medications (ASMs) may also have a negative impact on neonatal brains and contribute to detrimental neurodevelopmental outcomes. The objectives were to evaluate: 1) the impact of implementing a neonatal seizure treatment protocol in 2016; 2) the influence of AS...

Congenital heart disease (CHD) has been associated with structural brain growth and long-term developmental impairments, including deficits in learning, memory, and executive functions. Altered functional connectivity has been shown to be altered in neonates born with CHD; however, it is unclear if these early life alterations are also present duri...

Resting state fMRI (rsfMRI) has been shown to be a promising tool to study intrinsic functional connectivity and assess its integrity in cerebral development. In neonates, where fMRI is limited to few paradigms, rsfMRI was shown to be a relevant tool to explore regional interactions of brain networks. However, to identify the resting state networks...

Magnetic resonance imaging (MRI) is currently under investigation as a non-invasive tool to monitor neurodevelopmental trajectories and predict risk of cognitive deficits following white matter injury (WMI) in very preterm infants. In the present study, we evaluated the capacity of multimodal MRI (high-resolution T2-weighted imaging and diffusion t...

Semi-supervised learning has emerged as an appealing strategy to train deep models with limited supervision. Most prior literature under this learning paradigm resorts to dual-based architectures, typically composed of a teacher-student duple. To drive the learning of the student, many of these models leverage the aleatoric uncertainty derived from...

Introduction: Inflammation-induced white matter injury (WMI) in preterm infants is characterized by microglia activation, astrogliosis, oxidative stress and neurodevelopmental impairments. Microglia and astrocytes activation can be described under a broad spectrum of activation profile with extremes described as pro-inflammatory/neurotoxic (M1 mic...

Perinatal hypoxic/ischemic (HI) brain injury is a major clinical problem with devastating neurodevelopmental outcomes in neonates. During HI brain injury, dysregulated factor production contributes to microvascular impairment. Glycolysis-derived lactate accumulated during ischemia has been proposed to protect against ischemic injury, but its mechan...

Flexible, self-healing and adhesive conductive materials with Young's modulus matching biological tissues are highly desired for applications in bioelectronics. Here, we report self-healing, stretchable, highly adhesive and conductive hydrogels obtained by mixing polyvinyl alcohol, sodium tetraborate and a screen printing paste containing the condu...

Objectives: Significant resources are devoted to neonatal prolonged mechanical ventilation (NPMV), but little is known about the outcomes in those children. Our primary objective was to describe the NPMV respiratory, digestive, and neurological outcomes at 18 months corrected age. Our second objective was on the early identification of which patien...

Objective This study aimed to assess whether the hospital level of care where asphyxiated neonates treated with hypothermia were originally born influences their outcome. Study Design We conducted a retrospective cohort study of all asphyxiated neonates treated with hypothermia in a large metropolitan area. Birth hospitals were categorized based on...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Objectives To assess the feasibility and tolerance of NeuroPAP, a new non-invasive ventilation mode which continuously adjusts (during both inspiration and expiration) the pressure support proportionally to the diaphragm electrical activity (Edi), in preterm infants and to evaluate the impact on ventilation pressure and Edi. Design Prospective cro...

Introduction Deep learning neural networks are especially potent at dealing with structured data, such as images and volumes. Both modified LiviaNET and HyperDense-Net performed well at a prior competition segmenting 6-month-old infant magnetic resonance images, but neonatal cerebral tissue type identification is challenging given its uniquely inve...

Preterm infants are vulnerable to inflammation‐induced white matter injury (WMI), which is associated with neurocognitive impairment and increased risk of neuropsychiatric diseases in adulthood. Epigenetic mechanisms, particularly DNA methylation, play a role in normal development and modulate the response to pathological challenges. Our aims were...

Purpose: Targeting β-adrenergic receptor signaling with propranolol has emerged as a potential candidate to counteract choroidal neovascularization (CNV). Little is known of its effect on macrophages, which play a critical role in CNV. We investigated the effect of propranolol on angiogenic response of mononuclear phagocytes (MPs). Methods: The...

Retinopathy of prematurity (ROP) is characterized by an initial retinal avascularization, followed by pathologic neovascularization. Recently, choroidal thinning has also been detected in children formerly diagnosed with ROP; a similar sustained choroidal thinning is observed in ROP models. But the mechanism underlying the lack of choroidal revascu...

Perinatal infection and inflammatory episodes in preterm infants are associated with diffuse white matter injury (WMI) and adverse neurological outcome. Inflammation-induced WMI was previously shown to be linked with later hippocampal atrophy and learning and memory impairments in preterm infants. Early evaluation of injury load and therapeutic res...

Background Brain injury and abnormal maturation in the neonatal period is associated with long-term changes underlying significant cognitive, motor, language and behavioural deficiencies. Our understanding of clear cerebral disruptors of brain development and the extent of their impact are still limited, mostly due to the lack of robust non-invasiv...

With increasing advances in the field of medical brain imaging, the known spectrum of white matter lesions has expanded, and we can now assess the presence of punctate white matter lesions (PWML). These focal small lesions are quite frequently detected in the preterm infant and in full-term infants with congenital heart malformations with, some stu...

Background The extension of sepsis encompassing the preterm newborn’s brain is often overlooked due to technical challenges in this highly vulnerable population, yet it leads to substantial long-term neurodevelopmental disabilities. In this study, we demonstrate how neonatal neuroinflammation following postnatal E. coli lipopolysaccharide (LPS) exp...

Quality control (QC) of brain magnetic resonance images (MRI) is an important process requiring a significant amount of manual inspection. Major artifacts, such as severe subject motion, are easy to identify to naïve observers but lack automated identification tools. Clinical trials involving motion‐prone neonates typically pool data to obtain suff...

Antenatal inflammation as seen with chorioamnionitis is harmful to foetal/neonatal organ development including to eyes. Although the major pro-inflammatory cytokine IL-1β participates in retinopathy induced by hyperoxia (a predisposing factor to retinopathy of prematurity), the specific role of antenatal IL-1β associated with preterm birth (PTB) in...

Neonatal brain injury suffered by preterm infants and newborns with some medical conditions can cause significant neurodevelopmental disabilities. MRI is a preferred method to detect these accidents and perform in vivo evaluation of the brain. However, the commercial availability and optimality of receive coils for the neonatal brain is limited, wh...

Aside from injury identification, MRI of the newborn brain has given us insight into cortical and white matter development, identified windows of vulnerabilities, enabled the introduction of therapeutic hypothermia which has become the standard of care in neonatal asphyxia, and is fostering leapfrogging discoveries in the field of neuro-genetics. T...

Our open source quality control pipeline, DICOMetrics, attempted to classify 2D MRI images with major quality issues using data obtained from an example neonatal brain imaging study with 52 participants and 1040 DICOM images. The pipeline operated at per 2D DICOM file level and leveraged numerous existing no-reference image analyses metrics to quan...

There is compelling evidence from randomized clinical trials that therapeutic hypothermia for full term or near-term neonates with moderate to severe hypoxic-ischemic encephalopathy (HIE) improves survival without disability. However, more than half of all infants with HIE have mild encephalopathy, as shown by hyperalertness, agitation and hyperton...

The cover image, by Luis Akakpo et al., is based on the Research Article User-independent diffusion tensor imaging analysis pipelines in a rat model presenting ventriculomegalia: A comparison study, DOI: 10.1002/nbm.3793.

Automated analysis of diffusion tensor imaging (DTI) data is an appealing way to process large datasets in an unbiased manner. However, automation can sometimes be linked to a lack of interpretability. Two whole-brain, automated and voxelwise methods exist: voxel-based analysis (VBA) and tract-based spatial statistics (TBSS). In VBA, the amount of...

Very preterm newborns have an increased risk of developing an inflammatory cerebral white matter injury that may lead to severe neuro-cognitive impairment. In this study we performed functional connectivity (fc) analysis using resting-state optical imaging of intrinsic signals (rs-OIS) to assess the impact of inflammation on resting-state networks...

Background: Being born small for gestational age has been associated with neurodevelopmental disabilities and smaller gray matter volumes in childhood. However, it is not known if these changes persist in adults and whether SGA has any impact on attention memory and IQ. Aims: The goal of this study was to evaluate the association between birth w...

Introduction • Inflammatory white matter injury (WMI) is a leading cause of neurocognitive and neurodevelopmental impairment in preterms 1. • Resting-state networks (RSNs) are shown to be altered following preterm birth 2 ,3. • Most literature on RSNs are based on functional MRI studies, which is not well suited when working with smalls animal mode...

Purpose: Seizures are common in critically ill neonates. Both seizures and antiepileptic treatments may lead to short term complications and worsen the outcomes. Predicting the risks of seizure reoccurrence could enable individual treatment regimens and better outcomes. We aimed to identify EEG signatures of seizure reoccurrence by investigating p...

Background: Intracallosal lipopolysaccharide (LPS) injection in neonatal rats mimics diffuse white matter injury commonly observed in preterm infants. A reduced functional connectivity (FC) assessed by MRI has been shown in preterm with white matter injury. Objective: The aim of the study was to assess the long term impact of inflammation on FC in...

INTRODUCTION: Inflammatory white matter injury (WMI) is a leading cause of neurocognitive and neurodevelopmental impairment in very preterm newborns. The development of sensitive and quantitative tools for the assessment of WMI is an important step towards the development of an effective neuroprotective therapy. Resting-state networks (RSNs) have b...

Introduction: Large-scale magnetic resonance imaging (MRI) studies in newborns is difficult since the data is often hard to collect and aggregate. The Canadian Neonatal Brain Platform is a new initiative supported by Brain Canada to facilitate multi-center neonatal brain imaging studies and collect clinical neonatal brain MRI with shared common pro...

Introduction: Being born Small for Gestational Age has been associated with neurodevelopmental disabilities and smaller gray matter volumes and cortical thickness in childhood. However, specific impact of being born small for gestational age on cortical gray matter anatomy, in correlation to comprehensive neurocognitive evaluation, has rarely been...

Brain injury in preterm infants, as demonstrated with neonatal MRI, is associated with adverse neurodevelopmental outcomes in cognitive, language, motor, educational, behavioral, and social domains.¹ Such brain injury is heterogeneous, is rarely localized, and evolves over time. White matter injury (WMI) in preterm infants is by far the most freque...

Background and aims Being born Small for Gestational Age (SGA) has been associated with neurodevelopmental disabilities and smaller gray matter volumes and cortical thickness in childhood, as well as smaller surface areas in adults. However, gray matter volume has never been studied in adults. The goal of this study was to evaluate the association...

Retinopathy of prematurity (ROP), the most common cause of blindness in premature infants, has long been associated with inner retinal alterations. However, recent studies reveal outer retinal dysfunctions in patients formerly afflicted with ROP. We have recently demonstrated that choroidal involution occurs early in retinopathy. Herein, we investi...

Microglia, mainly known for their role in innate immunity and modulation of neuroinflammation, play an active role in central nervous system development and homeostasis. Depending on the context and environmental stimuli, microglia adopt a broad spectrum of activation status from pro-inflammatory, associated with neurotoxicity, to anti-inflammatory...

Seizures are common and worsen the outcome in critically ill neonates. Predicting seizure recurrence could allow individualizing antiepileptic treatment and improving the outcome. To identify EEG signatures of seizure recurrence, we investigated periictal spectral power and electrographic characteristics of seizures in five consecutive asphyxiated...

Objective: To investigate how rewarming impacts the evolution of EEG background in neonates with hypoxic-ischemic encephalopathy (HIE) undergoing therapeutic hypothermia (TH). Methods: We recruited a retrospective cohort of 15 consecutive newborns with moderate (9) and severe (6) HIE monitored with a continuous EEG during TH and at least 12h aft...

SESSION TITLE: Mechanical Ventilation Poster Discussion SESSION TYPE: Original Investigation Poster Discussion PRESENTED ON: Tuesday, October 27, 2015 at 02:45 PM - 04:15 PM PURPOSE: Prolonged mechanical ventilation (PMV) and chronic mechanical ventilation (CMV) in neonates is associated with a high morbidity and mortality. Risks factors associated...

Preterm infants are especially vulnerable to infection-induced white matter injury, associated with cerebral palsy, cognitive and psychomotor impairment, and other adverse neurological outcomes. The etiology of such lesions is complex and multifactorial. Furthermore, timing and length of exposure to infection also influence neurodevelopmental outco...

Using rsOIS (Resting-State Optical Imaging of Intrinsic Signals), we demonstrated a non-invasive approach to assess cerebral changes in response to inflammatory white matter injury. Surprisingly, lipopolysaccharide (LPS) exposure induced an increase in inter-hemispheric functional connectivity (fc); this may reflect a possible compensatory mechanis...

Periventricular leukomalacia (PVL) is a condition that may cause significant neurodevelopmental handicap in premature newborns. It is characterized by white matter injury, associated with inflammation. This work aimed to assess the impact of inflammation on cerebral oxygen saturation (sO2) using depth-sensitive photoacoustic tomography (PAT). The a...

Importance Premature infants are at risk of developing encephalopathy of prematurity, which is associated with long-term neurodevelopmental delay. Erythropoietin was shown to be neuroprotective in experimental and retrospective clinical studies.Objective To determine if there is an association between early high-dose recombinant human erythropoie...

The precise assessment of cerebral saturation changes during an inflammatory injury in the developing brain, such as seen in periventricular leukomalacia, is not well defined. This study investigated the impact of inflammation on locoregional cerebral oxygen saturation in a newborn rodent model using photoacoustic imaging. 1 mg/kg of lipopolysaccha...

Background: Lipopolysaccharide (LPS) injection in the corpus callosum (CC) of rat pups results in diffuse white matter injury similar to the main neuropathology of preterm infants. The aim of this study was to characterize the structural and metabolic markers of acute inflammatory injury by high-field magnetic resonance imaging (MRI) magnetic reso...

BACKGROUND: Accurate detection of the acute inflammatory changes of periventricular leukomalacia (PVL) would allow the identification of newborns requiring neuroprotective intervention. Photoacoustic imaging has recently emerged as an appealing alternative to Near Infrared Spectroscopy, which combines the high spatial resolution of acoustics with t...

In gyrencephalic species such as sheep, precise anatomical and microstructural characterization of the consequences of fetal inflammation remains scarce. The goal of this study was to characterize changes in white matter (WM) structure using advanced magnetic resonance imaging (MRI) following lipopolysaccharide (LPS) exposure in the preterm-equival...

The present study evaluated the potential of using the phase of T2* weighted MR images to characterize myelination during brain development and pathology in rodents at 9.4 T. Phase contrast correlated with myelin content assessed by histology and suggests that most contrast between white and cortical gray matter is modulated by myelin. Ex vivo expe...

Backgrounds and aims: With steady prematurity rates and increasing number of surviving extremely preterm infants, the risk to develop encephalopathy of prematurity characterised by white matter (WM) injury, WM loss and subsequent abnormalities in cortical development and long-term neurodevelopmental delay, has become a major concern in neonatal car...

Background and aims: Prenatal inflammation is currently being seen as one important factor of brain injury in preterm infants. Currently there is a lack of an early biomarker of brain injury. In addition it is not known how prenatal inflammation influences fetal metabolism in short and long-term.Here, we 1)characterise the fetal metabolic response...

Preterm infants exhibit chronic deficits in white matter (WM) and cortical maturation. Although fetal infection/inflammation may contribute to WM pathology, the factors contributing to cortical changes are largely unknown. We examined the effect of fetal lipopolysaccharide (LPS) exposure on WM and cortical development as assessed by magnetic resona...

To identify quantitative MRI indices of injury in the brain following neonatal hypoxic-ischemic brain injury, we subjected mouse pups to hypoxia-ischemia on postnatal day 7 and obtained conventional and diffusion-weighted in vivo images of the brain 24 h later followed by histological assessment. T(2)-weighted images showed increased signal intensi...

Objective: Preterm infants exhibit chronic deficits in white matter and cortical aturation. Although there is evidence that fetal infection/inflammation may contribute to white matter pathology, little is known on the factors contributing to cortical changes. We examined the effect of fetal lipopolysaccharide (LPS) exposure on white matter and cort...

Background: Clinicians when evaluating MRI of preterm infants are in need for simple measurements that reflect actual brain tissue volumes. Subarachnoid space (SAS) measurement might be a reflection of white and grey matter integrity.Methods: A cohort of 43 preterm infants was imaged at term equivalent by MRI (gestational age 29 ± 2 wks, birth weig...

Intracallosal injection of lipopolysaccharide (LPS) is a well-established model of white matter injury in the developing brain. Early alterations of tissue metabolism after an inflammatory insult are unknown. As such, we sought to define its in vivo spectroscopic signature 24 hours after injection. 8 Wistar rats injected under ultrasound guidance w...

In recent years, considerable research has focused on the biological effect of endocrine‐disrupting chemicals. Bisphenol A (BPA) has been implicated as an endocrine‐disrupting chemical (EDC) due to its ability to mimic the action of endogenous estrogenic hormones. The aim of this study was to assess the effect of perinatal exposure to BPA on cerebr...

Significant human brain growth occurs during the third trimester, with a doubling of whole brain volume and a fourfold increase of cortical gray matter volume. This is also the time period during which cortical folding and gyrification take place. Conditions such as intrauterine growth restriction, prematurity and cerebral white matter injury have...

Cerebral periventricular white matter injury stands as a leading cause of cognitive, behavioral and motor impairment in preterm infants. There is epidemiological and histopathological evidence demonstrating the role of prenatal or neonatal inflammation in brain injury in preterm infants. In order to define the effect of an inflammatory insult in th...

Neurological deficits caused by H-I (hypoxia-ischaemia) to the perinatal brain are often severely debilitating and lead to motor impairment, intellectual disability and seizures. Perinatal brain injury is distinct from adult brain injury in that the developing brain is undergoing the normal process of neuronal elimination by apoptotic cell death an...

To compare preterm (PT) and full-term (FT) infant hippocampal volumes and to investigate the relations among PT hippocampal volume, perinatal risk factors, and neurodevelopmental outcome. A total of 184 PT and 32 full-term infants underwent magnetic resonance imaging at term equivalent age with manual segmentation of the hippocampi on coronal slice...

The hippocampus is known to be vulnerable to hypoxia, stress, and undernutrition, all likely to be present in fetal intrauterine growth restriction (IUGR). The effect of IUGR in preterm infants on the hippocampus was studied using 3D magnetic resonance imaging at term-equivalent age Thirteen preterm infants born with IUGR after placental insufficie...

Brain injury occurring in the perinatal period is an important etiology of subsequent neurodevelopmental disabilities. Magnetic resonance imaging (MRI) is a tool that is used to evaluate the nature of brain injury in the human infant. MRI techniques have also been applied to various animal models of perinatal injury. The most commonly used model is...

There are now a number of evidences showing that the developing organism adapts to the environment it finds itself. Short- and long-term adjustments, referred as "programming", take place and will initially induce intrauterine growth retardation but will also have consequences that will appear later in life. The use of magnetic resonance imaging (M...

Objectives: References values of amplitude-integrated EEG (aEEG) for preterm infants are based on qualitative assessments of the global aspect of the tracing. We were interested in the measurement of more objective quantitative parameters in the 72 hours aEEG of prematures with no focal brain lesion on MRI. Methods: 15 preterm infants below 32 wee...