MRI and spectroscopy in (near) term neonates with perinatal asphyxia and therapeutic hypothermia

Volumetric apparent diffusion coefficient histogram analysis in term neonatal asphyxia treated with hypothermia

OBJECTIVES

Our aim is to estimate the long-term neurological sequelae and prognosis in term neonatal asphyxia treated with hypothermia via volumetric apparent diffusion coefficient (ADC) map histogram analysis (HA).

METHODS

Brain MRI studies of 83 term neonates with asphyxia who received whole-body hypothermia treatment and examined between postnatal (PN) fourth and sixth days were retrospectively re-evaluated by 2 radiologists. Volumetric HA was performed for the areas frequently affected in deep and superficial asphyxia (thalamus, lentiform nucleus, posterior limb of internal capsule, corpus callosum forceps major, and perirolandic cortex-subcortical white matter) on ADC map. The quantitative ADC values were obtained separately for each region. Qualitative-visual (conventional) MRI findings were also re-evaluated. Neonates were examined neurodevelopmentally according to the Revised Brunet-Lezine scale. The distinguishability of long-term neurodevelopmental outcomes was statistically investigated.

RESULTS

With HA, the adverse neurodevelopmental outcomes could only be distinguished from mild-moderated impairment and normal development at the thalamus with 10th percentile ADC (P = .02 and P = .03, respectively) and ADCmin (P = .03 and P = .04, respectively). Also with the conventional MRI findings, adverse outcome could be distinguished from mild-moderated impairment (P = .04) and normal development (P = .04) via cytotoxic oedema of the thalamus, corpus striatum, and diffuse cerebral cortical.

CONCLUSION

The long-term adverse neurodevelopmental outcomes in newborns with asphyxia who received whole-body hypothermia treatment can be estimated similarly with volumetric ADC-HA and the conventional assessment of the ADC map.

ADVANCES IN KNOWLEDGE

This study compares early MRI ADC-HA with neurological sequelae in term newborns with asphyxia who received whole-body hypothermia treatment. We could not find any significant difference in predicting adverse neurological sequelae between the visual-qualitative evaluation of the ADC map and HA.

MRI predictors of long-term outcomes of neonatal hypoxic ischaemic encephalopathy: a primer for radiologists

This review aims to serve as a foundational resource for general radiologists, enhancing their understanding of the role of Magnetic Resonance Imaging (MRI) in early prognostication for newborns diagnosed with hypoxic ischaemic encephalopathy (HIE). The article explores the application of MRI as a predictive instrument for determining long-term outcomes in newborns affected by HIE. With HIE constituting a leading cause of neonatal mortality and severe long-term neurodevelopmental impairments, early identification of prognostic indicators is crucial for timely intervention and optimal clinical management. We examine current literature and recent advancements to provide an in-depth overview of MRI predictors, encompassing brain injury patterns, injury scoring systems, spectroscopy, and diffusion imaging. The potential of these MRI biomarkers in predicting long-term neurodevelopmental outcomes and the probability of epilepsy is also discussed.

Amplitude-Integrated Electroencephalography Evolution and Magnetic Resonance Imaging Injury in Mild and Moderate to Severe Neonatal Encephalopathy

OBJECTIVE

 This study aimed to describe the evolution of amplitude-integrated electroencephalography (aEEG) in neonatal encephalopathy (NE) during therapeutic hypothermia (TH) and evaluate the association between aEEG parameters and magnetic resonance imaging (MRI) injury.

STUDY DESIGN

 aEEG data of infants who underwent TH were reviewed for background, sleep wake cycling (SWC), and seizures. Conventional electroencephalography (cEEG) background was assessed from the reports. Discordance of background on aEEG and cEEG was defined if there was a difference in the severity of the background. MRI injury (total score ≥ 5) was assessed by using the Weeke scoring system.

RESULTS

 A total of 46 infants were included; 23 (50%) with mild NE and 23 (50%) with moderate to severe NE. Comparing mild NE with moderate to severe NE, the initial aEEG background differed with more mild being continuous (70 vs. 52%), with fewer being discontinuous (0 vs. 22%) and flat tracing (0 vs. 4%), whereas burst suppression (4 vs. 4%) and low voltage (26 vs. 18%) did not differ. There was a notably common discordance between the background assessment on cEEG with aEEG in 82% with continuous and 40% low voltage aEEG background. MRI abnormalities were identified in four infants with mild NE and seven infants with moderate to severe NE. MRI injury was associated with aEEG seizures in infants with moderate to severe NE.

CONCLUSION

 aEEG seizures are useful to predict MRI injury in moderate to severe NE infants. There is a large discrepancy between aEEG, cEEG, and MRI in neonates treated by TH.

KEY POINTS

· MRI injury was identified in 29% of moderate NE infants and in 50% of severe NE infants.. · aEEG seizures were associated with MRI injury in the moderate to severe NE infants.. · MRI injury was identified in 16% infants with mild NE.. · Mild NE infants with normal aEEG were unlikely to have MRI injury.. · There was a large discrepancy between aEEG, cEEG, and MRI in infants treated by TH..

Apparent diffusion coefficient values can predict neuromotor outcome in term neonates with hypoxic-ischaemic encephalopathy

AIM

To determine the apparent diffusion coefficient (ADC) in brain structures during the first 2 weeks of life and its relation with neurological outcome for hypoxic-ischaemic encephalopathy (HIE) in term neonates.

METHODS

We retrospectively evaluated 56 term-born neonates. The ADC values were measured for 11 brain regions. The clinical outcomes at least 2 years of age were defined as normal outcome, mild disability and severe disability. The area under curves (AUCs) by ROC analysis were performed to predict the neurodevelopmental outcomes. The clinical outcomes were compared between favourable outcome and adverse outcome and also between normal outcome and unfavourable outcome.

RESULTS

Thirty-four patients were judged as normal outcome, 10 as mild disability and 12 as severe disability. When the clinical outcomes were compared between favourable outcome and adverse outcome, the AUC on the 1st week was highest value at the thalamus. When the clinical outcomes were compared between normal outcome and unfavourable outcome, the AUC on the 1st week was highest at the thalamus.

CONCLUSION

The ADC values in the thalamus in the 1st week can predict the neurological outcome. The ADC values in centrum semiovale on the 2nd week can be used to predict neurodevelopmental outcomes.

Serum biomarkers of hypoxic-ischemic brain injury

Brain injury is a multifaceted condition arising from nonspecific damage to nervous tissue. The resulting cognitive developmental impairments reverberate through patients' lives, affecting their families, and even the broader economic landscape. The significance of early brain injury detection lies in its potential to stave off severe consequences and enhance the effectiveness of tailored therapeutic interventions. While established methods like neuroimaging and neurophysiology serve as valuable diagnostic tools, their demanding nature restricts their accessibility, particularly in scenarios such as small hospitals, nocturnal or weekend shifts, and cases involving unstable patients. Hence, there is a pressing need for more accessible and efficient diagnostic avenues. Among the spectrum of brain injuries, hypoxic-ischemic encephalopathy stands out as a predominant affliction in the pediatric population. Diagnosing brain injuries in newborns presents challenges due to the subjective nature of assessments like Apgar scores and the inherent uncertainty in neurological examinations. In this context, methods like magnetic resonance and ultrasound hold recommendations for more accurate diagnosis. Recognizing the potential of serum biomarkers derived from blood samples, this paper underscores their promise as a more expedient and resource-efficient means of assessing brain injuries. The review compiles current insights into serum biomarkers, drawing from experiments conducted on animal models as well as human brain pathologies. The authors aim to elucidate specific characteristics, temporal profiles, and the available corpus of experimental and clinical data for serum biomarkers specific to brain injuries. These include neuron-specific enolase (NSE), ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), S100 calcium-binding protein beta (S100B), glial fibrillary acidic protein (GFAP), and high-mobility-group-protein-box-1 (HMGB1). This comprehensive endeavor contributes to advancing the understanding of brain injury diagnostics and potential avenues for therapeutic intervention.

Additional Value of 3-Month Cranial Magnetic Resonance Imaging in Infants with Neonatal Encephalopathy following Perinatal Asphyxia

OBJECTIVE

To assess the evolution of neonatal brain injury noted on magnetic resonance imaging (MRI), develop a score to assess brain injury on 3-month MRI, and determine the association of 3-month MRI with neurodevelopmental outcome in neonatal encephalopathy (NE) following perinatal asphyxia.

METHODS

This was a retrospective, single-center study including 63 infants with perinatal asphyxia and NE (n = 28 cooled) with cranial MRI <2 weeks and 2-4 months after birth. Both scans were assessed using biometrics, a validated injury score for neonatal MRI, and a new score for 3-month MRI, with a white matter (WM), deep gray matter (DGM), and cerebellum subscore. The evolution of brain lesions was assessed, and both scans were related to 18- to 24-month composite outcome. Adverse outcome included cerebral palsy, neurodevelopmental delay, hearing/visual impairment, and epilepsy.

RESULTS

Neonatal DGM injury generally evolved into DGM atrophy and focal signal abnormalities, and WM/watershed injury evolved into WM and/or cortical atrophy. Although the neonatal total and DGM scores were associated with composite adverse outcomes, the 3-month DGM score (OR 1.5, 95% CI 1.2-2.0) and WM score (OR 1.1, 95% CI 1.0-1.3) also were associated with composite adverse outcomes (occurring in n = 23). The 3-month multivariable model (including the DGM and WM subscores) had higher positive (0.88 vs 0.83) but lower negative predictive value (0.83 vs 0.84) than neonatal MRI. Inter-rater agreement for the total, WM, and DGM 3-month score was 0.93, 0.86, and 0.59.

CONCLUSIONS

In particular, DGM abnormalities on 3-month MRI, preceded by DGM abnormalities on the neonatal MRI, were associated with 18- to 24-month outcome, indicating the utility of 3-month MRI for treatment evaluation in neuroprotective trials. However, the clinical usefulness of 3-month MRI seems limited compared with neonatal MRI.

Advanced Neuromonitoring Modalities on the Horizon: Detection and Management of Acute Brain Injury in Children

Timely detection and monitoring of acute brain injury in children is essential to mitigate causes of injury and prevent secondary insults. Increasing survival in critically ill children has emphasized the importance of neuroprotective management strategies for long-term quality of life. In emergent and critical care settings, traditional neuroimaging modalities, such as computed tomography and magnetic resonance imaging (MRI), remain frontline diagnostic techniques to detect acute brain injury. Although detection of structural and anatomical abnormalities remains crucial, advanced MRI sequences assessing functional alterations in cerebral physiology provide unique diagnostic utility. Head ultrasound has emerged as a portable neuroimaging modality for point-of-care diagnosis via assessments of anatomical and perfusion abnormalities. Application of electroencephalography and near-infrared spectroscopy provides the opportunity for real-time detection and goal-directed management of neurological abnormalities at the bedside. In this review, we describe recent technological advancements in these neurodiagnostic modalities and elaborate on their current and potential utility in the detection and management of acute brain injury.

Introduction of ultra-high-field MR brain imaging in infants: vital parameters, temperature and comfort

Background

Brain MRI in infants at ultra-high-field scanners might improve diagnostic quality, but safety should be evaluated first. In our previous study, we reported simulated specific absorption rates and acoustic noise data at 7 Tesla.

Methods

In this study, we included twenty infants between term-equivalent age and three months of age. The infants were scanned on a 7 Tesla MRI directly after their clinically indicated 3 Tesla brain MRI scan. Vital parameters, temperature, and comfort were monitored throughout the process. Brain temperature was estimated during the MRI scans using proton MR spectroscopy.

Results

We found no significant differences in vital parameters, temperature, and comfort during and after 7 Tesla MRI scans, compared to 3 Tesla MRI scans.

Conclusions

These data confirm our hypothesis that scanning infants at 7 Tesla MRI appears to be safe and we identified no additional risks from scanning at 3 Tesla MRI.

Epinephrine vs placebo in neonatal resuscitation: ROSC and brain MRS/MRI in term piglets

BACKGROUND

We aimed to investigate the effect of epinephrine vs placebo on return of spontaneous circulation (ROSC) and brain magnetic resonance spectroscopy and imaging (MRS/MRI) in newborn piglets with hypoxic cardiac arrest (CA).

METHODS

Twenty-five piglets underwent hypoxia induced by endotracheal tube clamping until CA. The animals were randomized to CPR + intravenous epinephrine or CPR + placebo (normal saline). The primary outcome was ROSC, and secondary outcomes included time-to-ROSC, brain MRS/MRI, and composite endpoint of death or severe brain MRS/MRI abnormality.

RESULTS

ROSC was more frequent in animals treated with epinephrine than placebo; 10/13 vs 4/12, RR = 2.31 (95% CI: 1.09-5.77). We found no difference in time-to-ROSC (120 (113-211) vs 153 (116-503) seconds, p = 0.7) or 6-h survival (7/13 vs 3/12, p = 0.2). Among survivors, there was no difference between groups in brain MRS/MRI. We found no difference in the composite endpoint of death or severe brain MRS/MRI abnormality; RR = 0.7 (95% CI: 0.37-1.19).

CONCLUSIONS

Resuscitation with epinephrine compared to placebo improved ROSC frequency after hypoxic CA in newborn piglets. We found no difference in time-to-ROSC or the composite endpoint of death or severe brain MRS/MRI abnormality.

IMPACT

In a newborn piglet model of hypoxic cardiac arrest, resuscitation with epinephrine compared to placebo improved the rate of return of spontaneous circulation and more than doubled the 6-h survival. Brain MRS/MRI biomarkers were used to evaluate the effect of epinephrine vs placebo. We found no difference between groups in the composite endpoint of death or severe brain MRS/MRI abnormality. This study adds to the limited evidence regarding the effect and safety of epinephrine; the lack of high-quality evidence from randomized clinical trials was highlighted in the latest ILCOR 2020 guidelines, and newborn animal studies were specifically requested.

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

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

Hypocapnia in early hours of life is associated with brain injury in moderate to severe neonatal encephalopathy

OBJECTIVE

To evaluate the association between hypocapnia within the first 24 h of life and brain injury assessed by a detailed MRI scoring system in infants receiving therapeutic hypothermia (TH) for neonatal encephalopathy (NE) stratified by the stage of NE.

STUDY DESIGN

This retrospective cohort study included infants who received TH for mild to severe NE.

RESULTS

188 infants were included in the study with 48% having mild and 52% moderate-severe NE. Infants with moderate-severe NE spent more time in hypocapnia (PCO₂ ≤ 35 mmHg) and presented with more severe brain injury on MRI compared to mild cases. The MRI injury score increased by 6% for each extra hour spent in hypocapnic range in infants with moderate-severe NE. There was no association between hypocapnia and injury scores in mild cases.

CONCLUSION

In infants with moderate-severe NE, the hours spent in hypocapnia was an independent predictor of brain injury.

Hypoglycemia in Infants with Hypoxic-Ischemic Encephalopathy Is Associated with Additional Brain Injury and Worse Neurodevelopmental Outcome

OBJECTIVE

To determine the incidence of hypoglycemia among infants with hypoxic-ischemic encephalopathy (HIE) who received therapeutic hypothermia, and to assess whether infants with hypoglycemia had more brain injury on magnetic resonance imaging (MRI) or differences in neurodevelopmental outcome.

STUDY DESIGN

Single-center, retrospective cohort study including infants cooled for HIE. Hypoglycemia (blood glucose <36.0 mg/dL <2 hours and <46.8 mg/dL ≥2 hours after birth) was analyzed in the period before brain MRI. Brain injury was graded using a validated score. Motor and neurocognitive outcomes were assessed at 2 years for all survivors, and 5.5 years for a subset who had reached this age.

RESULTS

Of 223 infants analyzed, 79 (35.4%) had hypoglycemia. MRI was performed in 187 infants. Infants with hypoglycemia (n = 65) had higher brain injury scores (P = .018). After adjustment for HIE severity, hypoglycemia remained associated with higher injury scores (3.6 points higher; 95% CI, 0.8-6.4). Hyperglycemia did not affect MRI scores. In survivors at 2 years (n = 154) and 5.5 years (n = 102), a univariable analysis showed lower 2-year motor scores and lower motor and cognitive scores at preschool age in infants with hypoglycemia. After adjustment for HIE severity, infants with hypoglycemia had 9 points lower IQs (P = .023) and higher odds of adverse outcomes at preschool age (3.6; 95% CI, 1.4-9.0).

CONCLUSIONS

More than one-third of infants cooled for HIE had hypoglycemia. These infants had a higher degree of brain injury on MRI and lower cognitive function at preschool age. Strategies to avoid hypoglycemia should be optimized in this setting.

Brain proton magnetic resonance spectroscopy and neurodevelopment after preterm birth: a systematic review

BACKGROUND

Preterm infants are at risk of neurodevelopmental impairments. At present, proton magnetic resonance spectroscopy (¹H-MRS) is used to evaluate brain metabolites in asphyxiated term infants. The aim of this review is to assess associations between cerebral ¹H-MRS and neurodevelopment after preterm birth.

METHODS

PubMed and Embase were searched to identify studies using ¹H-MRS and preterm birth. Eligible studies for this review included ¹H-MRS of the brain, gestational age ≤32 weeks, and neurodevelopment assessed at a corrected age (CA) of at least 12 months up to the age of 18 years.

RESULTS

Twenty papers evaluated ¹H-MRS in preterm infants at an age between near-term and 18 years and neurodevelopment. ¹H-MRS was performed in both white (WM) and gray matter (GM) in 12 of 20 studies. The main regions were frontal and parietal lobe for WM and basal ganglia for GM. N-acetylaspartate/choline (NAA/Cho) measured in WM and/or GM is the most common metabolite ratio associated with motor, language, and cognitive outcome at 18-24 months CA.

CONCLUSIONS

NAA/Cho in WM assessed at term-equivalent age was associated with motor, cognitive, and language outcome, and NAA/Cho in deep GM was associated with language outcome at 18-24 months CA.

IMPACT

In preterm born infants, brain metabolism assessed using ¹H-MRS at term-equivalent age is associated with motor, cognitive, and language outcomes at 18-24 months. ¹H-MRS at term-equivalent age in preterm born infants may be used as an early indication of brain development. Specific findings relating to NAA were most predictive of outcome.

Magnetic Resonance Spectroscopy of Hypoxic-Ischemic Encephalopathy After Cardiac Arrest

BACKGROUND AND OBJECTIVES

To correlate brain metabolites with clinical outcome using magnetic resonance spectroscopy (MRS) in patients undergoing targeted temperature management (TTM) after cardiac arrest and assess their relationships to MRI and EEG variables.

METHODS

A prospective cohort of 50 patients was studied. The primary outcome was coma recovery to follow commands. Comparison of MRS measures in the posterior cingulate gyrus, parietal white matter, basal ganglia, and brainstem were also made to 25 normative controls.

RESULTS

Fourteen of 50 patients achieved coma recovery before hospital discharge. There was a significant decrease in total N-acetylaspartate (NAA/Cr) and an increase in lactate/creatine (Lac/Cr) in patients who did not recover, with changes most prominent in the posterior cingulate gyrus. Patients who recovered had decrease in NAA/Cr as compared to controls. NAA/Cr had a strong monotonic relationship with MRI cortical apparent diffusion coefficient (ADC); Lac level exponentially increased with decreasing ADC. EEG suppression/burst suppression was strongly associated with Lac elevation.

DISCUSSION

NAA and Lac changes are associated with clinical/MRI/EEG changes consistent with hypoxic-ischemic encephalopathy (HIE) and are most prominent in the posterior cingulate gyrus. NAA/Cr decrease observed in patients with good outcomes suggests mild HIE in patients asymptomatic at hospital discharge. The appearance of cortical Lac represents a deterioration of aerobic energy metabolism and is associated with EEG background suppression, synaptic transmission failure, and severe, potentially irreversible HIE.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that in patients undergoing TTM after cardiac arrest, brain MRS-determined decrease in total NAA/Cr and an increase in Lac/Cr are associated with an increased risk of not recovering.

A correlation between Magnetic Resonance Spectroscopy (1-H MRS) and the neurodevelopment of two-year-olds born preterm in an EPIRMEX cohort study

BACKGROUND

Preterm infants are at risk of neurodevelopmental impairments. At present, proton magnetic resonance spectroscopy (1H-MRS) is currently used to evaluate brain metabolites in asphyxiated term infants. The purpose of this study was to identify in the preterm EPIRMEX cohort any correlations between (1H-MRS) metabolites ratio at term equivalent age (TEA) and neurodevelopmental outcomes at 2 years.

METHODS

Our study included EPIRMEX eligible patients who were very preterm infants (gestational age at birth ≤32 weeks) and who underwent a brain MRI at TEA and ¹H-MRS using a monovoxel technique. The volumes of interest (VOI) were periventricular white matter posterior area and basal ganglia. The ratio of N Acetyl Aspartate (NAA) to Cho (Choline), NAA to Cr (creatine), Cho to Cr, and Lac (Lactate) to Cr were measured. Neurodevelopment was assessed at 24 months TEA with ASQ (Ages and Stages Questionnaire).

RESULTS

A total of 69 very preterm infants had a 1H-MRS at TEA. In white matter there was a significant correlation between a reduction in the NAA/Cho ratio and a total ASQ and/or abnormal communication score, and an increase in the Lac/Cr ratio and an abnormality of fine motor skills. In the gray nuclei there was a trend correlation between the reduction in the NAA/Cho ratio and sociability disorders; and the increase in the Lac/Cr ratio and an anomaly in problem-solving.

CONCLUSIONS

Using NAA as a biomarker, the vulnerability of immature oligodendrocytes in preterm children at TEA was correlated to neurodevelopment at 2 years. Similarly, the presence of lactate at TEA was associated with abnormal neurodevelopment at 2 years in the preterm brain.

A predictive value of early clinical parameters for abnormal brain MRI scan in neonates treated with therapeutic hypothermia

Introduction:Brain MRI scans can predict neurodevelopmental outcomes in neonates treated with therapeutic hypothermia. It is a common clinical practice to perform brain MRI before discharge, but brain MRI scans performed at around four months of age have a better prognostic value for a long-term neurological outcome in asphyxiated neonates. Aim: To identify which of three selected clinical parameters (oral feeding ability, muscle tone, history of seizure) evaluated 10 days after therapeutic hypothermia could predict the primary outcome of an abnormal brain MRI. Methods: We reviewed the medical records of neonates ≥ 36 completed weeks of gestation consecutively treated with therapeutic hypothermia who underwent brain MRI. Clinical parameters on day 10 after therapeutic hypothermia were correlated with brain MRI findings in the first 7-14 days of life. Logic regression analysis was performed using all three covariates of the clinical status, with an abnormal MRI as the primary outcome. Results: Brain MRI was abnormal in 42 (51.85 %) neonates with the following distribution of brain injury patterns: abnormal signal in the basal nuclei in 6, an abnormal signal in the cortex in 16, an abnormal signal both in the cortex and basal nuclei in 20 neonates. Out of three analyzed clinical parameters, feeding difficulty (P < 0.001, OR 8.3, 95% CI 2.9 - 28.9) and a history of seizures (P < 0.001, OR 11.95, 95% CI 3 - 44.5) were significantly associated with an abnormal MRI. Conclusion: Neonates who were capable of full oral feeding by day 10 after therapeutic hypothermia and had no history of seizures were unlikely to have an abnormal MRI. This may be used in selective planning of pre-discharge MRI in asphyxiated neonates.

Predictive performance and metabolite dynamics of proton MR spectroscopy in neonatal hypoxic-ischemic encephalopathy

BACKGROUND

Prognostic value of proton MR spectroscopy (H-MRS) in hypoxic-ischemic encephalopathy (HIE) is acknowledged; however, effects of gestational age (GA) and postnatal age (PA) on prediction and metabolite levels are unknown.

METHODS

One hundred and sixty-nine newborns with moderate-to-severe HIE were studied, having ≥1 H-MRS scan during postnatal days 0-14 and known neurodevelopmental outcome (Bayley-II score/cerebral palsy/death). Initial scans were categorized by PA (day 1-3/4-6/≥7), and metabolite ratios were compared by predictive value. Metabolite dynamics were assessed in a total of 214 scans performed in the study population, using regression modeling, with predictors GA, PA, and outcome.

RESULTS

N-acetyl-aspartate (NAA)/creatine (Cr) and myo-inositol (mI)/NAA height ratios were consistently associated with outcome throughout the first 14 days, with the highest predictive value in the late (≥7 days) period (AUC = 0.963 and 0.816, respectively). Neither GA nor PA had an overall effect on these metabolite ratios, which showed strongest association with outcome (p < 0.001). Assessed separately in patients with good outcome, GA became a significant covariate for metabolite ratios (p = 0.0058 and 0.0002, respectively). However, this association disappeared in the poor outcome group.

CONCLUSIONS

In HIE, NAA/Cr and mI/NAA give most accurate outcome prediction throughout postnatal days 0-14. GA only affected metabolite levels in the good outcome group.

IMPACT

Proton MR spectroscopy metabolite ratios N-acetyl-aspartate/creatine and myo-inositol/N-acetyl-aspartate have persistently high predictive value throughout postnatal days 0-14 in newborns with hypoxic-ischemic encephalopathy, with the highest predictive power between postnatal days 7 and 14. Overall, neither metabolite ratio was affected by gestational age nor by postnatal age, while they showed the strongest association with neurological outcome. However, in newborns facing good outcome, metabolite ratios were associated with gestational age, whereas in cases facing poor outcome, this association disappeared. Proton MR spectroscopy provides valuable prognostic information in neonatal hypoxic-ischemic encephalopathy throughout the first 2 weeks of life, irrespective of the timing of MR scan.

Magnetic resonance imaging and spectroscopy in evaluation of hypoxic ischemic encephalopathy in pediatric age group

Background

Hypoxic ischemic encephalopathy is a major cause of pediatric mortality and morbidity, with possible long-term neurologic sequel, such as cerebral palsy. With improvements in care of at-risk neonates, more children survive. This makes it increasingly important to assess, soon after birth, the prognosis of children with hypoxic-ischemic encephalopathy. The aim of the study was to assess the additive role of magnetic resonance spectroscopy over conventional MRI in diagnosis and early prediction of pathological motor development in neonates with hypoxic ischemic encephalopathy.

Results

MRS ratios showed significant difference between unfavorable and normal outcome infants. MRS ratios as Lac/Cr, NAA/Cr and NAA/Cho within basal ganglia, thalamus and white matter can significantly differentiate between patients with normal and pathological outcome at 1 year.

Lac/Cr positively correlates with the severity of HIE. Both NAA/Cr and NAA/Cho negatively correlate with the severity of the disease. Ratios cutoff values as Lac/Cr above 0.38 and 0.42 in basal ganglia and white matter, respectively, NAA/Cr below 0.9 and 0.8 in basal ganglia and occipital white matter, respectively, and NAA/Cho below 0.29 and 0.31 in basal ganglia and frontal white matter, respectively, were significantly predictive of pathological outcome.

Conclusion

High Lac/Cr, low NAA/Cr and low NAA/Cho ratios within examined regions of the brain including deep grey matter nuclei as well as white matter are associated with an adverse outcome in infants with perinatal asphyxia. MRS is an accurate quantitative MR biomarker within the neonatal period for prediction of neurodevelopmental outcome after perinatal HIE. MRS may be useful in early clinical management decisions, and counseling parents thereby ensuring appropriate early intervention and rehabilitation.

Comparison of Predictive Values of Magnetic Resonance Biomarkers Based on Scan Timing in Neonatal Encephalopathy Following Therapeutic Hypothermia

OBJECTIVE

To determine the optimal quantitative magnetic resonance (MR) biomarker in neonatal encephalopathy following therapeutic hypothermia based on scan timing.

STUDY DESIGN

This retrospective study included 98 neonates (35-41 weeks of gestation) with neonatal encephalopathy, who underwent therapeutic hypothermia; diffusion-weighted imaging and proton MR spectroscopy were performed at 24-96 hours (n = 56) and 7-14 days (n = 92) after birth, respectively, to estimate apparent diffusion coefficient (ADC) values, N-acetylaspartate and N-acetylaspartylglutamate (tNAA), lactate, and choline concentrations, and lactate/tNAA, tNAA/choline ratios in the deep gray matter. Adverse outcomes included death or neurodevelopmental impairment at 18-22 months of age. We used receiver operating characteristic curves to examine the prognostic accuracy of each MR biomarker.

RESULTS

Deep gray matter tNAA concentrations showed the best prognostic value, with an area under the curve (AUC) of 0.97 and 1.00 at 24-96 hours and 7-14 days after birth, respectively. At 24-96 hours of age, ADC values, lactate concentrations, and lactate/tNAA ratios showed prognostic value with AUCs of 0.90, 0.95, and 0.97, respectively. At 7-14 days of age, the AUCs of ADC values, lactate, and lactate/tNAA ratios were 0.61, 0.67, and 0.80, respectively; these were lower than those at 24-96 hours of age.

CONCLUSIONS

During the first 2 weeks of life, the deep gray matter tNAA concentration was the most accurate quantitative MR biomarker. Although ADC values, lactate levels, and lactate/tNAA ratios also showed high prognostic value during 24-96 hours of life, only tNAA retained high prognostic value in the second week of life.

Neuroimaging in the term newborn with neonatal encephalopathy

Neuroimaging is widely used to aid in the diagnosis and clinical management of neonates with neonatal encephalopathy (NE). Yet, despite widespread use clinically, there are few published guidelines on neuroimaging for neonates with NE. This review outlines the primary patterns of brain injury associated with hypoxic-ischemic injury in neonates with NE and their frequency, associated neuropathological features, and risk factors. In addition, it provides an overview of neuroimaging methods, including the most widely used scoring systems used to characterize brain injury in these neonates and their utility as predictive biomarkers. Last, recommendations for neuroimaging in neonates with NE are presented.

1H-MR Spectroscopy of the Early Developmental Brain, Neonatal Encephalopathies, and Neurometabolic Disorders

MRI interpretations of the pediatric brain are often challenging for general radiologists and clinicians because MR  signals and morphology are continuously changing in the developing brain. Furthermore, the developing brain reacts differently to injuries, resulting in imaging characteristics that differ from those of the mature brain. Proton magnetic resonance spectroscopy (¹H-MRS) is a non-invasive method for assessing neurological abnormalities at the microscopic level and measures in vivo brain metabolites using a clinical MR machine. In MR examinations of the pediatric brain, ¹H-MRS demonstrates its powerful diagnostic capability when MRI is insufficient for diagnostic features. MRI and ¹H-MRS may be complementary tools for diagnosing and monitoring diseases. However, there is currently no consensus on how to include ¹H-MRS in clinical MR examinations. An overview of the clinical implementation of ¹H-MRS for the assessment of early pediatric developmental brains as well as the diagnosis, prognostification, and disease monitoring of various non-neoplastic brain disorders, including neonatal encephalopathies and neurometabolic/neurodegenerative diseases, was provided herein. Qualitative and quantitative ¹H-MRS is a powerful non-invasive tool for accessing various brain metabolites to confirm age appropriate peaks and detect abnormal peaks or deficient or reduced peaks, which may facilitate the identification of metabolic and neurodegenerative disorders as well as damage associated with hypoxic-ischemic encephalopathy (HIE). Moreover, ¹H-MRS has potential as a biomarker for monitoring therapeutic efficacy in metabolic diseases and neonatal HIE. It also provides insights into the pathophysiologies of various disorders, which may facilitate the use of novel therapeutic approaches. Therefore, ¹H-MRS needs to be included more frequently in routine clinical MR examinations of pediatric patients with neurological disorders.

Integrating neuroimaging biomarkers into the multicentre, high-dose erythropoietin for asphyxia and encephalopathy (HEAL) trial: rationale, protocol and harmonisation

INTRODUCTION

MRI and MR spectroscopy (MRS) provide early biomarkers of brain injury and treatment response in neonates with hypoxic-ischaemic encephalopathy). Still, there are challenges to incorporating neuroimaging biomarkers into multisite randomised controlled trials. In this paper, we provide the rationale for incorporating MRI and MRS biomarkers into the multisite, phase III high-dose erythropoietin for asphyxia and encephalopathy (HEAL) Trial, the MRI/S protocol and describe the strategies used for harmonisation across multiple MRI platforms.

METHODS AND ANALYSIS

Neonates with moderate or severe encephalopathy enrolled in the multisite HEAL trial undergo MRI and MRS between 96 and 144 hours of age using standardised neuroimaging protocols. MRI and MRS data are processed centrally and used to determine a brain injury score and quantitative measures of lactate and n-acetylaspartate. Harmonisation is achieved through standardisation-thereby reducing intrasite and intersite variance, real-time quality assurance monitoring and phantom scans.

ETHICS AND DISSEMINATION

IRB approval was obtained at each participating site and written consent obtained from parents prior to participation in HEAL. Additional oversight is provided by an National Institutes of Health-appointed data safety monitoring board and medical monitor.

TRIAL REGISTRATION NUMBER

NCT02811263; Pre-result.

Brain MRI after therapeutic hypothermia in asphyxiated newborns: Predictive value at one year of imaging features

PURPOSE

To compare early brain MRI using a composite imaging score and outcome at one year in asphyxiated newborns treated by hypothermia.

METHODS

This retrospective study included for two years consecutive asphyxiated term newborns treated by hypothermia for hypoxic-ischemic encephalopathy, and who had brain MRI before day 8. Therapeutic hypothermia was initiated within the first 6 h of life and continued for 72 h. Imaging protocol included T1 and T2 sequences, diffusion-weighted imaging (DWI), evaluated with a specific composite score, and spectroscopy. Clinical evaluation was performed at one year of age, outcome was classified as favorable/unfavorable. The primary endpoint was the correlation between our MRI score and outcome with the definition of a threshold. The secondary endpoints were to find the most relevant criteria within the score and to evaluate objective signal measurements to support subjective criteria.

RESULTS

Among the 33 included patients, 9 died during the first days of life, 20 had a favorable outcome, 4 an unfavorable one. MRI score was correlated to a poor clinical outcome (p < 0.001). Most of the criteria within the score and spectroscopy results were relevant (p < 0.05). Cerebral edema was objectively assessed by the signal intensity ratio of white matter compared to cerebrospinal fluid (CSF) on T2-weighted images (p < 0.001).

CONCLUSION

MRI score was predictive of neurodevelopmental outcome at one year. The most relevant criteria within the score were DWI abnormalities in basal ganglia and thalami and loss of white-cortical grey matter differentiation. Signal intensity ratio between white matter and CSF higher than 0.75 supports the presence of edema.

Cerebellar injury in term neonates with hypoxic-ischemic encephalopathy is underestimated

BACKGROUND

Postmortem examinations frequently show cerebellar injury in infants with severe hypoxic-ischemic encephalopathy (HIE), while it is less well visible on MRI. The primary aim was to investigate the correlation between cerebellar apparent diffusion coefficient (ADC) values and histopathology in infants with HIE. The secondary aim was to compare ADC values in the cerebellum of infants with HIE and infants without brain injury.

METHODS

ADC values in the cerebellar vermis, hemispheres and dentate nucleus (DN) of (near-)term infants with HIE (n = 33) within the first week after birth were compared with neonates with congenital non-cardiac anomalies, normal postoperative MRIs and normal outcome (n = 22). Microglia/macrophage activation was assessed using CD68 and/or HLA-DR staining and Purkinje cell (PC) injury using H&E-stained slices. The correlation between ADC values and the histopathological measures was analyzed.

RESULTS

ADC values in the vermis (p = 0.021) and DN (p < 0.001) were significantly lower in infants with HIE compared to controls. ADC values in the cerebellar hemispheres were comparable. ADC values in the vermis were correlated with the number and percentage of normal PCs; otherwise ADC values and histology were not correlated.

CONCLUSION

Histopathological injury in the cerebellum is common in infants with HIE. ADC values underestimate histopathological injury.

IMPACT

ADC values might underestimate cerebellar injury in neonates with HIE. ADC values in the vermis and dentate nucleus of infants with HIE are lower compared to controls, but not in the cerebellar hemispheres. Abnormal ADC values are only found when cytotoxic edema is very severe. ADC values in the vermis are correlated with Purkinje cell injury in the vermis; furthermore, there were no correlations between ADC values and histopathological measures.

Interobserver Reliability of an MR Imaging Scoring System in Infants with Hypoxic-Ischemic Encephalopathy

BACKGROUND AND PURPOSE

MR imaging has a key role in predicting neurodevelopmental outcomes following neonatal hypoxic-ischemic encephalopathy (HIE). A novel MR imaging scoring system for hypoxic-ischemic brain injury was used in our patient population with the aim of assessing interobserver variability and developing subcategories for the severity of brain injury.

MATERIALS AND METHODS

We evaluated brain MR images of 252 infants who underwent hypothermia for HIE between 2014 and 2019. First, 40 infants were selected randomly to test interobserver variability. Discrepancies were identified during the assessment of the first 20 MR images. The remaining 20 MR images were scored after adjusting the scoring system. Second, we determined cutoff values for the severity of injury that were based on the percentiles of the total scores in the full cohort.

RESULTS

The interobserver reliability showed excellent agreement for the total score both before (intraclass correlation coefficient = 0.96; 95% CI 0.89-0.99) and after the adjustment (intraclass correlation coefficient = 0.96; 95% CI, 0.89-0.98). The average of the differences and the agreement interval between the 2 readers decreased after the adjustment. Subcategories of brain injury were the following: We considered a total score of ≤4 (≤75%) as normal, 5-10 (76%-90%) as mild, 11-15 (91%-95%) as moderate, and >15 (>95%) as severe brain injury. The agreement on the classification of brain injury improved in the second epoch (weighted κ = 0.723 versus 0.887).

CONCLUSIONS

The adjusted scoring system may lead to a higher degree of interrater agreement. The presented cutoff values may be used to determine the severity of brain injury in future clinical studies including infants with mild hypoxia-ischemia.

Proton Magnetic Resonance Spectroscopy Lactate/N-Acetylaspartate Within 48 h Predicts Cell Death Following Varied Neuroprotective Interventions in a Piglet Model of Hypoxia-Ischemia With and Without Inflammation-Sensitization

Despite therapeutic hypothermia, survivors of neonatal encephalopathy have high rates of adverse outcome. Early surrogate outcome measures are needed to speed up the translation of neuroprotection trials. Thalamic lactate (Lac)/N-acetylaspartate (NAA) peak area ratio acquired with proton (1H) magnetic resonance spectroscopy (MRS) accurately predicts 2-year neurodevelopmental outcome. We assessed the relationship between MR biomarkers acquired at 24-48 h following injury with cell death and neuroinflammation in a piglet model following various neuroprotective interventions. Sixty-seven piglets with hypoxia-ischemia, hypoxia alone, or lipopolysaccharide (LPS) sensitization were included, and neuroprotective interventions were therapeutic hypothermia, melatonin, and magnesium. MRS and diffusion-weighted imaging (DWI) were acquired at 24 and 48 h. At 48 h, experiments were terminated, and immunohistochemistry was assessed. There was a correlation between Lac/NAA and overall cell death [terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)] [mean Lac/NAA basal ganglia and thalamus (BGT) voxel r = 0.722, white matter (WM) voxel r = 0.784, p < 0.01] and microglial activation [ionized calcium-binding adapter molecule 1 (Iba1)] (BGT r = -0.786, WM r = -0.632, p < 0.01). Correlation with marker of caspase-dependent apoptosis [cleaved caspase 3 (CC3)] was lower (BGT r = -0.636, WM r = -0.495, p < 0.01). Relation between DWI and TUNEL was less robust (mean diffusivity BGT r = -0.615, fractional anisotropy BGT r = 0.523). Overall, Lac/NAA correlated best with cell death and microglial activation. These data align with clinical studies demonstrating Lac/NAA superiority as an outcome predictor in neonatal encephalopathy (NE) and support its use in preclinical and clinical neuroprotection studies.

Metabolic brain measurements in the newborn: Advances in optical technologies

Neonatal monitoring in neonatal intensive care is pushing the technological boundaries of newborn brain monitoring in order to improve patient outcome. There is an urgent need of a cot side, real time monitoring for assessment of brain injury severity and neurodevelopmental outcome, in particular for term newborn infants with hypoxic-ischemic brain injury. This topical review discusses why brain tissue metabolic monitoring is important in this group of infants and introduces the currently used neuromonitoring techniques for metabolic monitoring in the neonatal intensive care unit (NICU). New optical techniques that can monitor changes in brain metabolism together with brain hemodynamics at the cot side are presented. Early studies from these emerging technologies have demonstrated their potential to deliver continuous information regarding cerebral physiological changes in sick newborn infants in real time. The promises of these new tools as well as their potential limitations are discussed.

Brain temperature of infants with neonatal encephalopathy following perinatal asphyxia calculated using magnetic resonance spectroscopy

BACKGROUND

Little is known about brain temperature of neonates during MRI. Brain temperature can be estimated non-invasively with proton Magnetic Resonance Spectroscopy (¹H-MRS), but the most accurate ¹H-MRS method has not yet been determined. The primary aim was to estimate brain temperature using ¹H-MRS in infants with neonatal encephalopathy (NE) following perinatal asphyxia. The secondary aim was to compare brain temperature during MRI with rectal temperatures before and after MRI.

METHODS

In this retrospective study, brain temperature in 36 (near-)term infants with NE was estimated using short (36 ms) and long (288 ms) echo time (TE) ¹H-MRS. Brain temperature was calculated using two different formulas: formula of Wu et al. and a formula based on phantom calibration. The methods were compared. Rectal temperatures were collected <3 hours before and after MRI.

RESULTS

Brain temperatures calculated with the formula of Wu et al. and the calibrated formula were similar as well as brain temperatures derived from short and long TE ¹H-MRS. Rectal temperature did not differ before and after MRI.

CONCLUSIONS

Brain temperature can be measured using ¹H-MRS in daily clinical practice using the formula of Wu et al. with both short and long TE ¹H-MRS. Brain temperature remained within physiological range during MRI.

Fifteen-minute consultation: Therapeutic hypothermia for infants with hypoxic ischaemic encephalopathy-translating jargon, prognosis and uncertainty for parents

Hypoxic ischaemic encephalopathy may lead to death or severe long-term morbidity. Therapeutic hypothermia (TH) increases survival without impairments in childhood, but prognostic uncertainty may remain for years after birth. Clear and accurate communication is imperative but challenging. This article explores the predictive value of routinely performed assessments during TH, as well as the qualitative research relating to parental experience. This article will benefit paediatric trainees, consultants and nurse practitioners in providing: (1) the background information needed for initiating a conversation with parents regarding outcome and (2) optimising their communication with parents in translating jargon, prognosis and uncertainty.

Altered brain metabolism contributes to executive function deficits in school-aged children born very preterm

BACKGROUND

Executive function deficits in children born very preterm (VPT) have been linked to anatomical abnormalities in white matter and subcortical brain structures. This study aimed to investigate how altered brain metabolism contributes to these deficits in VPT children at school-age.

METHODS

Fifty-four VPT participants aged 8-13 years and 62 term-born peers were assessed with an executive function test battery. Brain metabolites were obtained in the frontal white matter and the basal ganglia/thalami, using proton magnetic resonance spectroscopy (MRS). N-acetylaspartate (NAA)/creatine (Cr), choline (Cho)/Cr, glutamate + glutamine (Glx)/Cr, and myo-Inositol (mI)/Cr were compared between groups and associations with executive functions were explored using linear regression.

RESULTS

In the frontal white matter, VPT showed lower Glx/Cr (mean difference: -5.91%, 95% CI [-10.50, -1.32]), higher Cho/Cr (7.39%, 95%-CI [2.68, 12.10]), and higher mI/Cr (5.41%, 95%-CI [0.18, 10.64]) while there were no differences in the basal ganglia/thalami. Lower executive functions were associated with lower frontal Glx/Cr ratios in both groups (β = 0.16, p = 0.05) and higher mI/Cr ratios in the VPT group only (interaction: β = -0.17, p = 0.02).

CONCLUSION

Long-term brain metabolite alterations in the frontal white matter may be related to executive function deficits in VPT children at school-age.

IMPACT

Very preterm birth is associated with long-term brain metabolite alterations in the frontal white matter. Such alterations may contribute to deficits in executive function abilities. Injury processes in the brain can persist for years after the initial insult. Our findings provide new insights beyond structural and functional imaging, which help to elucidate the processes involved in abnormal brain development following preterm birth. Ultimately, this may lead to earlier identification of children at risk for developing deficits and more effective interventions.

Predictors of Outcomes in Hypoxic-Ischemic Encephalopathy following Hypothermia: A Meta-Analysis

INTRODUCTION

Prediction of neurodevelopmental outcome in infants with hypoxic-ischemic encephalopathy remains an important challenge. Various studies have shown that the predictive ability of different modalities changed after the introduction of therapeutic hypothermia. This paper reviews the diagnostic test accuracy of the different modalities that are being used to predict neurodevelopmental outcomes following therapeutic hypothermia.

METHODS

A systematic literature search was performed using Embase and PubMed. Two reviewers independently included eligible studies and extracted data. The quality of the studies was assessed using the Quality in Prognosis Studies Tool. Meta-analyses were performed where possible.

RESULTS

Forty-seven articles and 3 conference abstracts were included, reporting on 3,072infants of whom 39% died or had an adverse neurodevelopmental outcome. A meta-analysis could be performed using 37 articles on (amplitude-integrated) electroencephalography (EEG), conventional magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), and proton magnetic resonance spectroscopy (1H-MRS). Amplitude-integrated EEG (aEEG) at 24 and 72 h showed similar high diagnostic OR, while aEEG at 6 h and EEG performed less, both due to a low specificity. For MRI, most studies reported scoring systems in which early (<8 days) MRI performed better than late (≥8 days) MRI. Injury to the posterior limb of the internal capsule on MRI or to the thalami on DWI were strong individual predictors, as was an increased lactate/N-acetylaspartate peak on 1H-MRS.

CONCLUSIONS

In the era of therapeutic hypothermia, the different modalities remain good predictors of neurodevelopmental outcome. However, timing should be taken into account. aEEG may initially be false positive and gets more reliable after 24 h. In contrast, MRI should be used during the first week, as its predictive value decreases afterwards.

Increased Use of Therapeutic Hypothermia in Infants with Milder Neonatal Encephalopathy due to Presumed Perinatal Asphyxia

INTRODUCTION

Adverse outcomes have been reported in infants with mild neonatal encephalopathy (NE). Increasing clinical experience with the application of therapeutic hypothermia (TH) may have resulted in the treatment of newborns with milder NE during recent years.

OBJECTIVE

To determine whether infants treated with TH in the initial years following implementation had a higher degree of NE than infants treated during subsequent years.

METHODS

Infants with NE treated with TH from February 2008 until July 2017 were included. Thompson and Sarnat scores, amplitude-integrated electroencephalography (aEEG) background patterns before the start of TH, and neurodevelopmental outcome at 2 years were compared between infants treated from February 2008 until October 2012 (period 1) and infants treated from November 2012 until July 2017 (period 2).

RESULTS

211 newborns with NE were treated with TH (period 1: n = 109, period 2: n = 102). Sarnat scores in period 1 and 2 were mild in 7.3 vs. 28.4%, moderate in 66.1 vs. 44.1%, and severe in 26.6 vs. 22.5%, respectively (p = 0.008). Thompson scores were lower in period 2 (median = 9, IQR 7-12) than in period 1 (median = 10, IQR 8.5-13.5, p = 0.018). The aEEGs and neurodevelopmental outcomes were comparable between the periods.

CONCLUSIONS

Based on Thompson and Sarnat scores, but not aEEG background patterns, infants treated during the second period had milder NE than infants treated during the first years following implementation of TH. There was no difference in 2 years neurodevelopmental outcome. Further research is necessary to evaluate the value of TH for infants with clinically mild NE.

The development and validation of a cerebral ultrasound scoring system for infants with hypoxic-ischaemic encephalopathy

BACKGROUND

Hypoxic-ischaemic encephalopathy (HIE) is an important cause of morbidity and mortality in neonates. When the gold standard MRI is not feasible, cerebral ultrasound (CUS) might offer an alternative. In this study, the association between a novel CUS scoring system and neurodevelopmental outcome in neonates with HIE was assessed.

METHODS

(Near-)term infants with HIE and therapeutic hypothermia, a CUS on day 1 and day 3-7 after birth and available outcome data were retrospectively included in cohort I. CUS findings on day 1 and day 3-7 were related to adverse outcome in univariate and the CUS of day 3-7 also in multivariable logistic regression analyses. The resistance index, the sum of deep grey matter and of white matter involvement were included in multivariable logistic regression analyses. A comparable cohort from another hospital was used for validation (cohort II).

RESULTS

Eighty-three infants were included in cohort I and 35 in cohort II. The final CUS scoring system contained the sum of white matter (OR = 2.6, 95% CI 1.5-4.7) and deep grey matter involvement (OR = 2.7, 95% CI 1.7-4.4). The CUS scoring system performed well in cohort I (AUC = 0.90) and II (AUC = 0.89).

CONCLUSION

This validated CUS scoring system is associated with neurodevelopmental outcome in neonates with HIE.

Early Post-cooling Brain Magnetic Resonance for the Prediction of Neurodevelopmental Outcome in Newborns with Hypoxic-Ischemic Encephalopathy

Aim and Objectives:

This study aimed to evaluate the predictive role of early post-cooling brain magnetic resonance for developmental outcome in newborns with hypoxic–ischemic encephalopathy.

Materials and Methods:

A retrospective cohort study was performed on 29 consecutive patients through magnetic resonance evaluation (visual analysis of the images and scoring of the detected lesions; mean diffusivity of semioval centre and lenticular nuclei; and area under the curve of basal ganglia N-acetylaspartate at proton magnetic resonance spectroscopic imaging) and Griffiths Mental Development Scales–third edition at 12 and 24 months.

Results:

Brain magnetic resonance was performed at a mean age of 5.7 ± 3.7 days. Newborns with no/minor magnetic resonance abnormalities had a better developmental outcome than patients with moderate or severe lesions. Structural and spectroscopic abnormalities in basal ganglia resulted in the most significant predictors for an unfavorable outcome.

Conclusion:

Normal magnetic resonance in early post-cooling phases is strongly associated with a favorable developmental outcome.

Probiotics decrease the stress response and intestinal permeability of term neonates with low Apgar scores

To observe the effect of probiotics on the stress responses and intestinal permeability of term neonates with low Apgar scores, the present study retrospectively analyzed the clinical data of 78 term neonates (42 males and 36 females). In the control group (n=38), total parenteral nutrition and comprehensive treatment (anti-infection therapy) were provided. In the observation group (n=40), the neonates were administered Lactobacillus Complex Capsules in addition to the control group treatment. The corticotropin-releasing factor level was determined using ELISA; cortisol levels were determined using a radioimmunoprecipitation assay; D-lactate and diamine oxidase levels were determined using ultraviolet spectrometry; procalcitonin levels were determined using ECL; and C-reactive protein levels were determined using a protein analyzer. Following treatment, the levels of all parameters were lower in the observation group compared with the control group, and the differences were statistically significant (P<0.05). In the observation group, the daily milk intake was 16.57±2.58 ml, which was significantly higher than that of the control group (13.26±1.87 ml), while the length of hospital stay and total parenteral nutrition time, which were 12.31±2.02 and 6.21±1.26 days, respectively, in the observation group, were significantly shorter than those of the control group (14.86±2.58 and 8.86±1.78 days, respectively), and the differences were statistically significant (P<0.001). The results of the present study suggested that probiotics can ameliorate the stress response and intestinal permeability of term neonates with low Apgar scores, thereby, facilitating gastrointestinal function recovery.

Neurodevelopmental effect of intracranial hemorrhage observed in hypoxic ischemic brain injury in hypothermia-treated asphyxiated neonates - an MRI study

BACKGROUND

Identification of early signs of hypoxic ischemic encephalopathy (HIE) with magnetic resonance imaging (MRI) has proven of prognostic significance. Yet, the importance of intracranial hemorrhage (ICH), being present concomitantly had not been investigated yet, despite the known influence of hypothermia on hemostasis. We aimed to determine whether presence of ICH on MRI alongside the signs of HIE have an impact on prognosis in neonates with the clinical diagnosis of HIE.

METHODS

A retrospective study of consecutively sampled 108 asphyxiated term infants admitted to a tertiary neonatal intensive care unit (between 2007 and 2016), treated with whole body hypothermia and having brain MRI within 1 week of life was conducted. Presence or absence of HIE signs on MRI (basal ganglia-thalamus, watershed pattern and total brain injury) and on MR spectroscopy (lactate peak with decreased normal metabolites measured by Lac/NAA ratio) and/or of the five major types of ICH were recorded. Neurodevelopmental outcome was measured with Bayley Scales of Infant Development-II (BSID-II) test. Death or abnormal neurodevelopment (BSID-II score < 85) was defined as poor outcome in Chi-square test. Multivariate logistic regression analysis was performed on survivors.

RESULTS

MRI and MR-spectroscopy (MRS) signs of HIE were present in 72% (n = 78). 36% (n = 39) of neonates had ICH, being mainly small in size. Chi-square test showed a relationship between neurodevelopmental outcome and initial MRI. Unadjusted logistic regression showed that neonates presenting MRI and MRS signs of HIE have 6.23 times higher odds for delayed mental development (OR = 6.2292; CI95% = [1.2642; 30.6934], p = 0.0246), than infants without imaging alterations; with no ICH effect on outcome. Adjustment for clinical and imaging parameters did not change the pattern of results, i.e. HIE remained an independent risk factor for delayed neurodevelopment (OR = 6.2496; CI95% = [1.2018; 32.4983], p = 0.0294), while ICH remained to have no significant effect.

CONCLUSION

HIE related MRI abnormalities proved to be important prognostic factors of poor outcome in cooled asphyxiated infants when present, suggesting that early MRI with MRS is beneficial for prognostication. Interestingly, ICHs present in about one third of all cases had no significant effect on neurodevelopmental outcome, despite the known hemostasis altering effects of hypothermia.

Automatic extraction of the intracranial volume in fetal and neonatal MR scans using convolutional neural networks

•

Automatic intracranial volume segmentation.

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Fetal and neonatal MRI.

•

Deep learning.

MR images of infants and fetuses allow non-invasive analysis of the brain. Quantitative analysis of brain development requires automatic brain tissue segmentation that is typically preceded by segmentation of the intracranial volume (ICV). Fast changes in the size and morphology of the developing brain, motion artifacts, and large variation in the field of view make ICV segmentation a challenging task.

We propose an automatic method for segmentation of the ICV in fetal and neonatal MRI scans. The method was developed and tested with a diverse set of scans regarding image acquisition parameters (i.e. field strength, image acquisition plane, image resolution), infant age (23–45 weeks post menstrual age), and pathology (posthaemorrhagic ventricular dilatation, stroke, asphyxia, and Down syndrome). The results demonstrate that the method achieves accurate segmentation with a Dice coefficient (DC) ranging from 0.98 to 0.99 in neonatal and fetal scans regardless of image acquisition parameters or patient characteristics. Hence, the algorithm provides a generic tool for segmentation of the ICV that may be used as a preprocessing step for brain tissue segmentation in fetal and neonatal brain MR scans.

Signal Change in the Mammillary Bodies after Perinatal Asphyxia

BACKGROUND AND PURPOSE

Research into memory deficits associated with hypoxic-ischemic encephalopathy has typically focused on the hippocampus, but there is emerging evidence that the medial diencephalon may also be compromised. We hypothesized that mammillary body damage occurs in perinatal asphyxia, potentially resulting in mammillary body atrophy and subsequent memory impairment.

MATERIALS AND METHODS

We retrospectively reviewed brain MRIs of 235 clinically confirmed full-term patients with hypoxic-ischemic encephalopathy acquired at a single center during 2004-2017. MRIs were performed within 10 days of birth (median, 6; interquartile range, 2). Two radiologists independently assessed the mammillary bodies for abnormal signal on T2-weighted and DWI sequences. Follow-up MRIs were available for 9 patients; these were examined for evidence of mammillary body and hippocampal atrophy.

RESULTS

In 31 neonates (13.2%), abnormal high mammillary body signal was seen on T2-weighted sequences, 4 with mild, 25 with moderate, and 2 with severe hypoxic-ischemic encephalopathy. In addition, restricted diffusion was seen in 6 neonates who had MR imaging between days 5 and 7. For these 31 neonates, the most common MR imaging pattern (41.9%) was abnormal signal restricted to the mammillary bodies with the rest of the brain appearing normal. Follow-up MRIs were available for 9 patients: 8 acquired between 3 and 19 months and 1 acquired at 7.5 years. There was mammillary body atrophy in 8 of the 9 follow-up MRIs.

CONCLUSIONS

Approximately 13% of full-term infants with hypoxic-ischemic encephalopathy showed abnormal high mammillary body signal on T2-weighted images during the acute phase, which progressed to mammillary body atrophy in all but 1 of the infants who had follow-up MR imaging. This mammillary body involvement does not appear to be related to the severity of encephalopathy, MR imaging patterns of hypoxic-ischemic encephalopathy, or pathology elsewhere in the brain.

Oxygen dependency of mitochondrial metabolism indicates outcome of newborn brain injury

There is a need for a method of real-time assessment of brain metabolism during neonatal hypoxic-ischaemic encephalopathy (HIE). We have used broadband near-infrared spectroscopy (NIRS) to monitor cerebral oxygenation and metabolic changes in 50 neonates with HIE undergoing therapeutic hypothermia treatment. In 24 neonates, 54 episodes of spontaneous decreases in peripheral oxygen saturation (desaturations) were recorded between 6 and 81 h after birth. We observed differences in the cerebral metabolic responses to these episodes that were related to the predicted outcome of the injury, as determined by subsequent magnetic resonance spectroscopy derived lactate/N-acetyl-aspartate. We demonstrated that a strong relationship between cerebral metabolism (broadband NIRS-measured cytochrome-c-oxidase (CCO)) and cerebral oxygenation was associated with unfavourable outcome; this is likely to be due to a lower cerebral metabolic rate and mitochondrial dysfunction in severe encephalopathy. Specifically, a decrease in the brain tissue oxidation state of CCO greater than 0.06 µM per 1 µM brain haemoglobin oxygenation drop was able to predict the outcome with 64% sensitivity and 79% specificity (receiver operating characteristic area under the curve = 0.73). With further work on the implementation of this methodology, broadband NIRS has the potential to provide an early, cotside, non-invasive, clinically relevant metabolic marker of perinatal hypoxic-ischaemic injury.

Pressure passivity of cerebral mitochondrial metabolism is associated with poor outcome following perinatal hypoxic ischemic brain injury

Hypoxic ischemic encephalopathy (HIE) leads to significant morbidity and mortality. Impaired autoregulation after hypoxia-ischaemia has been suggested to contribute further to injury. Thalamic lactate/N-Acetylasperate (Lac/NAA) peak area ratio of > 0.3 on proton (¹H) magnetic resonance spectroscopy (MRS) is associated with poor neurodevelopment outcome following HIE. Cytochrome-c-oxidase (CCO) plays a central role in mitochondrial oxidative metabolism and ATP synthesis. Using a novel broadband NIRS system, we investigated the impact of pressure passivity of cerebral metabolism (CCO), oxygenation (haemoglobin difference (HbD)) and cerebral blood volume (total haemoglobin (HbT)) in 23 term infants following HIE during therapeutic hypothermia (HT). Sixty-minute epochs of data from each infant were studied using wavelet analysis at a mean age of 48 h. Wavelet semblance (a measure of phase difference) was calculated to compare reactivity between mean arterial blood pressure (MABP) with oxCCO, HbD and HbT. OxCCO-MABP semblance correlated with thalamic Lac/NAA ( r = 0.48, p = 0.02). OxCCO-MABP semblance also differed between groups of infants with mild to moderate and severe injury measured using brain MRI score ( p = 0.04), thalamic Lac/NAA ( p = 0.04) and neurodevelopmental outcome at one year ( p = 0.04). Pressure passive changes in cerebral metabolism were associated with injury severity indicated by thalamic Lac/NAA, MRI scores and neurodevelopmental assessment at one year of age.

Fetal and neonatal neuroimaging

Magnetic resonance imaging (MRI) can provide detail of the soft tissues of the fetal and neonatal brain that cannot be obtained by any other imaging modality. Conventional T1 and T2 weighted sequences provide anatomic detail of the normally developing brain and can demonstrate lesions, including those associated with preterm birth, hypoxic ischemic encephalopathy, perinatal arterial stroke, infections, and congenital malformations. Specialized imaging techniques can be used to assess cerebral vasculature (magnetic resonance angiography and venography), cerebral metabolism (magnetic resonance spectroscopy), cerebral perfusion (arterial spin labeling), and function (functional MRI). A wealth of quantitative tools, most of which were originally developed for the adult brain, can be applied to study the developing brain in utero and postnatally including measures of tissue microstructure obtained from diffusion MRI, morphometric studies to measure whole brain and regional tissue volumes, and automated approaches to study cortical folding. In this chapter, we aim to describe different imaging approaches for the fetal and neonatal brain, and to discuss their use in a range of clinical applications.

Magnetic resonance spectroscopy assessment of brain injury after moderate hypothermia in neonatal encephalopathy: a prospective multicentre cohort study

Background

In neonatal encephalopathy, the clinical manifestations of injury can only be reliably assessed several years after an intervention, complicating early prognostication and rendering trials of promising neuroprotectants slow and expensive. We aimed to determine the accuracy of thalamic proton magnetic resonance (MR) spectroscopy (MRS) biomarkers as early predictors of the neurodevelopmental abnormalities observed years after neonatal encephalopathy.

Methods

We did a prospective multicentre cohort study across eight neonatal intensive care units in the UK and USA, recruiting term and near-term neonates who received therapeutic hypothermia for neonatal encephalopathy. We excluded infants with life-threatening congenital malformations, syndromic disorders, neurometabolic diseases, or any alternative diagnoses for encephalopathy that were apparent within 6 h of birth. We obtained T₁-weighted, T₂-weighted, and diffusion-weighted MRI and thalamic proton MRS 4–14 days after birth. Clinical neurodevelopmental tests were done 18–24 months later. The primary outcome was the association between MR biomarkers and an adverse neurodevelopmental outcome, defined as death or moderate or severe disability, measured using a multivariable prognostic model. We used receiver operating characteristic (ROC) curves to examine the prognostic accuracy of the individual biomarkers. This trial is registered with ClinicalTrials.gov, number NCT01309711.

Findings

Between Jan 29, 2013, and June 25, 2016, we recruited 223 infants who all underwent MRI and MRS at a median age of 7 days (IQR 5–10), with 190 (85%) followed up for neurological examination at a median age of 23 months (20–25). Of those followed up, 31 (16%) had moderate or severe disability, including one death. Multiple logistic regression analysis could not be done because thalamic N-acetylaspartate (NAA) concentration alone accurately predicted an adverse neurodevelopmental outcome (area under the curve [AUC] of 0·99 [95% CI 0·94–1·00]; sensitivity 100% [74–100]; specificity 97% [90–100]; n=82); the models would not converge when any additional variable was examined. The AUC (95% CI) of clinical examination at 6 h (n=190) and at discharge (n=167) were 0·72 (0·65–0·78) and 0·60 (0·53–0·68), respectively, and the AUC of abnormal amplitude integrated EEG at 6 h (n=169) was 0·73 (0·65–0·79). On conventional MRI (n=190), cortical injury had an AUC of 0·67 (0·60–0·73), basal ganglia or thalamic injury had an AUC of 0·81 (0·75–0·87), and abnormal signal in the posterior limb of internal capsule (PLIC) had an AUC of 0·82 (0·76–0·87). Fractional anisotropy of PLIC (n=65) had an AUC of 0·82 (0·76–0·87). MRS metabolite peak-area ratios (n=160) of NAA–creatine (<1·29) had an AUC of 0·79 (0·72–0·85), of NAA–choline had an AUC of 0·74 (0·66–0·80), and of lactate–NAA (>0·22) had an AUC of 0·94 (0·89–0·97).

Interpretation

Thalamic proton MRS measures acquired soon after birth in neonatal encephalopathy had the highest accuracy to predict neurdevelopment 2 years later. These methods could be applied to increase the power of neuroprotection trials while reducing their duration.

Funding

National Institute for Health Research UK.

Prognostic value of early, conventional proton magnetic resonance spectroscopy in cooled asphyxiated infants

Background

Neonatal hypoxic-ischemic encephalopathy (HIE) commonly leads to neurodevelopmental impairment, raising the need for prognostic tools which may guide future therapies in time. Prognostic value of proton MR spectroscopy (H-MRS) between 1 and 46 days of age has been extensively studied; however, the reproducibility and generalizability of these methods are controversial in a general clinical setting. Therefore, we investigated the prognostic performance of conventional H-MRS during first 96 postnatal hours in hypothermia-treated asphyxiated neonates.

Methods

Fifty-one consecutive hypothermia-treated HIE neonates were examined by H-MRS at three echo-times (TE = 35, 144, 288 ms) between 6 and 96 h of age, depending on clinical stability. Patients were divided into favorable (n = 35) and unfavorable (n = 16) outcome groups based on psychomotor and mental developmental index (PDI and MDI, Bayley Scales of Infant Development II) scores (≥ 70 versus < 70 or death, respectively), assessed at 18–26 months of age. Associations between 36 routinely measured metabolite ratios and outcome were studied. Age-dependency of metabolite ratios in whole patient population was assessed. Prognostic performance of metabolite ratios was evaluated by Receiver Operating Characteristics (ROC) analysis.

Results

Three metabolite ratios showed significant difference between outcome groups after correction for multiple testing (p < 0.0014): myo-inositol (mIns)/N-acetyl-aspartate (NAA) height, mIns/creatine (Cr) height, both at TE = 35 ms, and NAA/Cr height at TE = 144 ms. Assessment of age-dependency showed that all 3 metabolite ratios (mIns/NAA, NAA/Cr and mIns/Cr) stayed constant during first 96 postnatal hours, rendering them optimal for prediction. ROC analysis revealed that mIns/NAA gives better prediction for outcome than NAA/Cr and mIns/Cr with cut-off values 0.6798 0.6274 and 0.7798, respectively, (AUC 0.9084, 0.8396 and 0.8462, respectively, p < 0.00001); mIns/NAA had the highest specificity (95.24%) and sensitivity (84.62%) for predicting outcome of neonates with HIE any time during the first 96 postnatal hours.

Conclusions

Our findings suggest that during first 96 h of age even conventional H-MRS could be a useful prognostic tool in predicting the outcome of asphyxiated neonates; mIns/NAA was found to be the best and age-independent predictor.

Electronic supplementary material

The online version of this article (10.1186/s12887-018-1269-6) contains supplementary material, which is available to authorized users.

Proton Magnetic Resonance Spectroscopy Biomarkers in Neonates With Hypoxic-Ischemic Encephalopathy: A Systematic Review and Meta-Analysis

Background: Hypoxic-ischemic encephalopathy (HIE) is a major contributor to child mortality and morbidity. Reliable prognostication for HIE is of key importance. Proton magnetic resonance spectroscopy (¹H-MRS) is a quantitative, non-invasive method that has been demonstrated to be a suitable complementary tool for prediction. The aim of this study was to investigate the prognostic capability of ¹H-MRS in the era of therapeutic hypothermia (TH).

Methods: Databases, namely MEDLINE, Embase, Web of Science, and the Cochrane library (Cochrane Center Register of Controlled Trials), were searched for studies published before July 17, 2017. Study selection and data extraction were performed by two independent reviewers. The mean difference (MD) or standardized MD (SMD) and 95% confidence interval (CI) were calculated using random-effects models. Subgroup analyses were conducted based on the use of TH.

Results: Among the 1,150 relevant studies, seven were included for meta-analysis, but only two small studies were conducted under TH. For ¹H-MRS measurement, three peak area ratios revealed predictive values for adverse outcomes in TH subgroup and the combined results (with and without TH): N-acetylaspartate (NAA)/creatine in basal ganglia/thalamus (BG/T) in TH (MD −0.31, 95%CI −0.55 to −0.07) and combined results (MD −0.37, 95% CI −0.49 to −0.25); NAA/choline in BG/T in TH (MD −0.89, 95%CI −1.43 to −0.35) and combined results (MD −0.25, 95%CI −0.42 to −0.07); and myo-inositol/choline in cerebral cortex in TH (MD −1.94, 95%CI −3.69 to −0.19) and combined results (MD −1.64, 95%CI −2.64 to −0.64). Moreover, NAA relative concentration is associated with adverse outcomes: in TH (MD −0.04, 95%CI −0.06 to −0.02) and combined results (MD −0.06, 95%CI −0.11 to −0.01) in white matter; in TH (MD −0.04, 95%CI −0.07 to −0.01) and combined results (MD −0.05, 95%CI −0.07 to −0.02) in gray matter.

Conclusions: NAA may be a potential marker in outcome prediction for all HIE subjects. It seems that MDs for the ratios including NAA are larger than for its relative concentration, and therefore are more likely to be measurable in a clinical context. Larger prospective multicenter studies with a standardized protocol for both measurement protocols and analysis methods are required in future studies.

Brain Metabolism Alterations Induced by Pregnancy Swimming Decreases Neurological Impairments Following Neonatal Hypoxia-Ischemia in Very Immature Rats

Introduction: Prematurity, through brain injury and altered development is a major cause of neurological impairments and can result in motor, cognitive and behavioral deficits later in life. Presently, there are no well-established effective therapies for preterm brain injury and the search for new strategies is needed. Intra-uterine environment plays a decisive role in brain maturation and interventions using the gestational window have been shown to influence long-term health in the offspring. In this study, we investigated whether pregnancy swimming can prevent the neurochemical metabolic alterations and damage that result from postnatal hypoxic-ischemic brain injury (HI) in very immature rats.

Methods: Female pregnant Wistar rats were divided into swimming (SW) or sedentary (SE) groups. Following a period of adaptation before mating, swimming was performed during the entire gestation. At postnatal day (PND3), rat pups from SW and SE dams had right common carotid artery occluded, followed by systemic hypoxia. At PND4 (24 h after HI), the early neurochemical profile was measured by ¹H-magnetic resonance spectroscopy. Astrogliosis, apoptosis and neurotrophins protein expression were assessed in the cortex and hippocampus. From PND45, behavioral testing was performed. Diffusion tensor imaging and neurite orientation dispersion and density imaging were used to evaluate brain microstructure and the levels of proteins were quantified.

Results: Pregnancy swimming was able to prevent early metabolic changes induced by HI preserving the energetic balance, decreasing apoptotic cell death and astrogliosis as well as maintaining the levels of neurotrophins. At adult age, swimming preserved brain microstructure and improved the performance in the behavioral tests.

Conclusion: Our study points out that swimming during gestation in rats could prevent prematurity related brain damage in progeny with high translational potential and possibly interesting cost-benefits.

HIGHLIGHTS

- Prematurity is a major cause of neurodevelopmental impairments;

- Swimming during pregnancy reduces brain damage after HI injury;

- Pregnancy is an important but underestimated preventive window.

[Current status of the application of 1H-magnetic resonance spectroscopy in neonates with hypoxic-ischemic encephalopathy]

OBJECTIVE

To investigate the current status of the application of ¹H-magnetic resonance spectroscopy (¹H-MRS) in neonates with hypoxic-ischemic encephalopathy (HIE), and to describe the trend of research in the field.

METHODS

PubMed, EMBASE, and Web of Science were searched for English articles published up to January 10, 2018, with the combination of key words and MeSH terms. The articles were screened according to inclusion and exclusion criteria. Excel 2016, Bicomb 2.0, and VOSviewer1.6.6 were used to analyze the key words, to perform a cluster analysis of hot words, and to plot the knowledge map.

RESULTS

A total of 66 articles were included, and 27 high-frequency key words were extracted. The results showed that ¹H-MRS was mainly used in four directions of the clinical practice and scientific research on HIE. In clinical practice, ¹H-MRS attracted wide attention as a clinical examination for HIE and a tool for prognostic evaluation; in scientific research, ¹H-MRS was used in animal experiments and studies associated with mild hypothermia therapy.

CONCLUSIONS

As an auxiliary means of magnetic resonance imaging, ¹H-MRS plays an important role in investigating the pathogenesis of neonatal HIE, improving existing therapies, and evaluating the prognosis of neonates with HIE.

MRI Changes in the Thalamus and Basal Ganglia of Full-Term Neonates with Perinatal Asphyxia

BACKGROUND

Magnetic resonance imaging (MRI) is the standard neuroimaging technique to assess perinatal asphyxia-associated brain injury in full-term infants. Diffusion-weighted imaging (DWI) is most informative when assessed during the first week after the insult.

OBJECTIVES

To study the DWI abnormalities of the thalamus and basal ganglia in full-term infants with perinatal asphyxia.

METHODS

Fifty-five (near) term infants (normothermia n = 23; hypothermia n = 32) with thalamus and/or basal ganglia injury were included. MRI findings were assessed visually and quantitatively calculating apparent diffusion coefficient (ADC) values. Thalamus/basal ganglia ADC ratios were calculated to analyze the differences between these areas. Infants with an early MRI (days 1-3) or later MRI (days 4-7) were compared.

RESULTS

Isolated extensive thalamic injury was seen early, and focal thalamic and basal ganglia injury was seen later. On the early MRI, visual assessment underestimated abnormalities in the basal ganglia (59% abnormal vs. 90% abnormal on quantitative assessment; p = 0.015), suggesting the need for quantitative assessment. In infants treated with hypothermia, the thalamus/basal ganglia ADC ratio was lower.

CONCLUSIONS

Both visual analysis and quantitative evaluation of cerebral MRI after perinatal asphyxia are needed, especially during the first few days after birth. Timing of ADC changes is influenced by therapeutic hypothermia.