The course of apparent diffusion coefficient values following perinatal arterial ischemic stroke

Risk factors of neonatal stroke from different origins: a systematic review and meta-analysis

Given the persistent ambiguity regarding the etiology of neonatal stroke across diverse origins, our objective was to conduct a comprehensive evaluation of both qualitative and quantitative risk factors. An exhaustive search of eight databases was executed to amass all pertinent observational studies concerning risk factors for neonatal stroke from various origins. Subsequent to independent screening, data extraction, and bias assessment by two researchers, a meta-analysis was conducted utilizing RevMan and Stata software. Nineteen studies, encompassing a total of 30 factors, were incorporated into this analysis. Beyond established risk factors, our investigation unveiled gestational diabetes (OR, 5.51; P < 0.00001), a history of infertility (OR, 2.44; P < 0.05), placenta previa (OR, 3.92; P = 0.02), postdates (OR, 2.07; P = 0.01), preterm labor (OR, 2.32; P < 0.00001), premature rupture of membranes (OR, 3.02; P = 0.007), a prolonged second stage of labor (OR, 3.94; P < 0.00001), and chorioamnionitis (OR, 4.35; P < 0.00001) as potential risk factors for neonatal cerebral arterial ischemic stroke. Additionally, postdates (OR, 4.31; P = 0.003), preterm labor (OR, 1.60; P < 0.00001), an abnormal CTG tracing (OR, 9.32; P < 0.0001), cesarean section (OR, 4.29; P = 0.0004), male gender (OR, 1.73; P = 0.02), and vaginal delivery (OR, 1.39; P < 0.00001) were associated with an elevated risk for neonatal hemorrhagic stroke.

CONCLUSIONS

This study provides a succinct overview and comparative analysis of maternal, perinatal, and additional risk factors associated with neonatal cerebral artery ischemic stroke and neonatal hemorrhagic stroke, furnishing critical insights for healthcare practitioners involved in the diagnosis and prevention of neonatal stroke. This research also broadens the conceptual framework for future investigations.

WHAT IS KNOWN

• Research indicates that prenatal, perinatal, and neonatal risk factors can elevate the risk of neonatal arterial ischemic stroke (NAIS). However, the risk factors for neonatal cerebral arterial ischemic stroke remain contentious, and those for neonatal hemorrhagic stroke (NHS) and neonatal cerebral venous sinus thrombosis (CVST) are still not well-defined.

WHAT IS NEW

• This study is the inaugural comprehensive review and meta-analysis encompassing 19 studies that explore maternal, perinatal, and various risk factors linked to neonatal stroke of differing etiologies. Notably, our analysis elucidates eight risk factors associated with NAIS: gestational diabetes mellitus, a history of infertility, placenta previa, postdates, preterm birth, premature rupture of membranes, a prolonged second stage of labor, and chorioamnionitis. Furthermore, we identify six risk factors correlated with NHS: postdates, preterm birth, an abnormal CTG, the method of delivery, male gender, and vaginal delivery. Additionally, our systematic review delineates risk factors associated with CVST.

BOston Neonatal Brain Injury Dataset for Hypoxic Ischemic Encephalopathy (BONBID-HIE): Part I. MRI and Manual Lesion Annotation

Hypoxic ischemic encephalopathy (HIE) is a brain injury that occurs in 1 ~ 5/1000 term neonates. Accurate identification and segmentation of HIE-related lesions in neonatal brain magnetic resonance images (MRIs) is the first step toward predicting prognosis, identifying high-risk patients, and evaluating treatment effects. It will lead to a more accurate estimation of prognosis, a better understanding of neurological symptoms, and a timely prediction of response to therapy. We release the first public dataset containing neonatal brain diffusion MRI and expert annotation of lesions from 133 patients diagnosed with HIE. HIE-related lesions in brain MRI are often diffuse (i.e., multi-focal), and small (over half the patients in our data having lesions occupying <1% of brain volume). Segmentation for HIE MRI data is remarkably different from, and arguably more challenging than, other segmentation tasks such as brain tumors with focal and relatively large lesions. We hope that this dataset can help fuel the development of MRI lesion segmentation methods for HIE and small diffuse lesions in general.

Brain segmentation in patients with perinatal arterial ischemic stroke

BACKGROUND

Perinatal arterial ischemic stroke (PAIS) is associated with adverse neurological outcomes. Quantification of ischemic lesions and consequent brain development in newborn infants relies on labor-intensive manual assessment of brain tissues and ischemic lesions. Hence, we propose an automatic method utilizing convolutional neural networks (CNNs) to segment brain tissues and ischemic lesions in MRI scans of infants suffering from PAIS.

MATERIALS AND METHODS

This single-center retrospective study included 115 patients with PAIS that underwent MRI after the stroke onset (baseline) and after three months (follow-up). Nine baseline and 12 follow-up MRI scans were manually annotated to provide reference segmentations (white matter, gray matter, basal ganglia and thalami, brainstem, ventricles, extra-ventricular cerebrospinal fluid, and cerebellum, and additionally on the baseline scans the ischemic lesions). Two CNNs were trained to perform automatic segmentation on the baseline and follow-up MRIs, respectively. Automatic segmentations were quantitatively evaluated using the Dice coefficient (DC) and the mean surface distance (MSD). Volumetric agreement between segmentations that were manually and automatically obtained was computed. Moreover, the scan quality and automatic segmentations were qualitatively evaluated in a larger set of MRIs without manual annotation by two experts. In addition, the scan quality was qualitatively evaluated in these scans to establish its impact on the automatic segmentation performance.

RESULTS

Automatic brain tissue segmentation led to a DC and MSD between 0.78-0.92 and 0.18-1.08 mm for baseline, and between 0.88-0.95 and 0.10-0.58 mm for follow-up scans, respectively. For the ischemic lesions at baseline the DC and MSD were between 0.72-0.86 and 1.23-2.18 mm, respectively. Volumetric measurements indicated limited oversegmentation of the extra-ventricular cerebrospinal fluid in both the follow-up and baseline scans, oversegmentation of the ischemic lesions in the left hemisphere, and undersegmentation of the ischemic lesions in the right hemisphere. In scans without imaging artifacts, brain tissue segmentation was graded as excellent in more than 85% and 91% of cases, respectively for the baseline and follow-up scans. For the ischemic lesions at baseline, this was in 61% of cases.

CONCLUSIONS

Automatic segmentation of brain tissue and ischemic lesions in MRI scans of patients with PAIS is feasible. The method may allow evaluation of the brain development and efficacy of treatment in large datasets.

Neonatal Arterial Ischaemic Stroke: Advances in Pathologic Neural Death, Diagnosis, Treatment, and Prognosis

Neonatal arterial ischaemic stroke (NAIS) is caused by focal arterial occlusion and often leads to severe neurological sequelae. Neural deaths after NAIS mainly include necrosis, apoptosis, necroptosis, autophagy, ferroptosis, and pyroptosis. These neural deaths are mainly caused by upstream stimulations, including excitotoxicity, oxidative stress, inflammation, and death receptor pathways. The current clinical approaches to managing NAIS mainly focus on supportive treatments, including seizure control and anticoagulation. In recent years, research on the pathology, early diagnosis, and potential therapeutic targets of NAIS has progressed. In this review, we summarise the latest progress of research on the pathology, diagnosis, treatment, and prognosis of NAIS and highlight newly potential diagnostic and treatment approaches.

Perinatal Ischemic Stroke: Etiology and Imaging

Perinatal ischemic stroke is a common cause of lifelong disability.

Perinatal stroke syndromes: Similarities and diversities in aetiology, outcome and management

With a birth-prevalence of 37-67/100,000 (mostly term-born), perinatal stroke encompasses distinct disease-states with diverse causality, mechanism, time of onset, mode of presentation and outcome. Neonatal primary haemorrhagic stroke and ischemic events (also divided into neonatal arterial ischemic stroke and neonatal cerebral sinus venous thrombosis) that manifest soon after birth are distinguished from presumed perinatal - ischemic or haemorrhagic - stroke. Signs of the latter become apparent only beyond the neonatal period, most often with motor asymmetry or milestones delay, and occasionally with seizures. Acute or remote MRI defines the type of stroke and is useful for prognosis. Acute care relies on homeostatic maintenance. Seizures are often self-limited and anticonvulsant agents might be discontinued before discharge. Prolonged anticoagulation for a few weeks is an option in some cases of sinovenous thrombosis. Although the risk of severe impairment is low, many children develop mild to moderate multimodal developmental issues that require a multidisciplinary approach.

Bedside neurophysiological tests can identify neonates with stroke leading to cerebral palsy

OBJECTIVE

The unspecific symptoms of neonatal stroke still challenge its bedside diagnosis. We studied the accuracy of routine electroencephalography (EEG) and simultaneously recorded somatosensory evoked potentials (EEG-SEP) for diagnosis and outcome prediction of neonatal stroke.

METHODS

We evaluated EEG and EEG-SEPs from a hospital cohort of 174 near-term neonates with suspected seizures or encephalopathy, 32 of whom were diagnosed with acute ischemic or hemorrhagic stroke in MRI. EEG was scored for background activity and seizures. SEPs were classified as present or absent. Developmental outcome of stroke survivors was evaluated from medical records at 8- to 18-months age.

RESULTS

The combination of continuous EEG and uni- or bilaterally absent SEP (n = 10) was exclusively seen in neonates with a middle cerebral artery (MCA) stroke (specificity 100%). Moreover, 80% of the neonates with this finding developed with cerebral palsy. Bilaterally present SEPs did not exclude stroke, but predicted favorable neuromotor outcome in stroke survivors (positive predictive value 95%).

CONCLUSIONS

Absent SEP combined with continuous EEG background in near-term neonates indicates an MCA stroke and a high risk for cerebral palsy.

SIGNIFICANCE

EEG-SEP offers a bedside method for diagnostic screening and a reliable prediction of neuromotor outcome in neonates suspected of having a stroke.

Perinatal arterial ischemic stroke

Perinatal arterial ischemic stroke is a relatively common and serious neurologic disorder that can affect the fetus, the preterm, and the term-born infant. It carries significant long-term disabilities. Herein we describe the current understanding of its etiology, pathophysiology and classification, different presentations, and optimal early management. We discuss the role of different brain imaging modalities in defining the extent of lesions and the impact this has on the prediction of outcomes. In recent years there has been progress in treatments, making early diagnosis and the understanding of likely morbidities imperative. An overview is given of the range of possible outcomes and optimal approaches to follow-up and support for the child and their family in the light of present knowledge.

[Recommendations for imaging neonatal ischemic stroke]

Neuroimaging is critical for the diagnosis of neonatal arterial ischemic stroke (NAIS) and for prognosis estimation. The purpose of this work is to define guidelines of clinical neuroimaging for the diagnosis of NAIS, for the optimization of the imaging timing and for the assessment of the prognostic value of each imaging technique. A systematic search of electronic databases (Medline via Pubmed) for studies whose title and abstract were focused on NAIS has been conducted. One hundred and ten articles were selected and their results were analyzed by three Senior Practitioners of pediatric radiology using common methodology for guidelines elaboration within the group of experts gathered by Scientific Societies in the field. MRI with a diffu si on-weighted sequence (DWI) and T1, T2, and T2*-weighted sequences must be performed in the case of suspected NAIS (no sedation is required). In the first hours after the injury, an acute ischemic lesion is characterized by a hypersignal on the diffusion-weighted sequence, with a decrease of the apparent coefficient of diffusion (ADC). The best time to evaluate the extent of the ischemic lesion is between day 2 and day 4 after injury, when the ADC decrease reaches its nadir. In the acute phase, US may be useful as first imaging at the bedside to exclude other pathologies like large space-occupying hemorrhages, but its specific added value on NAIS diagnosis or prognosis assessment is very low. CT scan has no added value in NAIS, compared to MRI. Motor outcome is correlated with the extent of the lesion and with the presence of a definite injury of the corticospinal tract, which is well seen on the diffusion sequence at the acute stage. A secondary atrophy within the mesencephalon (cerebral peduncles) is tied in with a high risk of hemiplegia. Visual outcome is more often compromised in the case of lesions of the posterior cerebral artery territory.

Clinical neuroimaging in the preterm infant: Diagnosis and prognosis

Perinatal care advances emerging over the past twenty years have helped to diminish the mortality and severe neurological morbidity of extremely and very preterm neonates (e.g., cystic Periventricular Leukomalacia [c-PVL] and Germinal Matrix Hemorrhage - Intraventricular Hemorrhage [GMH-IVH grade 3-4/4]; 22 to < 32 weeks of gestational age, GA). However, motor and/or cognitive disabilities associated with mild-to-moderate white and gray matter injury are frequently present in this population (e.g., non-cystic Periventricular Leukomalacia [non-cystic PVL], neuronal-axonal injury and GMH-IVH grade 1-2/4). Brain research studies using magnetic resonance imaging (MRI) report that 50% to 80% of extremely and very preterm neonates have diffuse white matter abnormalities (WMA) which correspond to only the minimum grade of severity. Nevertheless, mild-to-moderate diffuse WMA has also been associated with significant affectations of motor and cognitive activities. Due to increased neonatal survival and the intrinsic characteristics of diffuse WMA, there is a growing need to study the brain of the premature infant using non-invasive neuroimaging techniques sensitive to microscopic and/or diffuse lesions. This emerging need has led the scientific community to try to bridge the gap between concepts or ideas from different methodologies and approaches; for instance, neuropathology, neuroimaging and clinical findings. This is evident from the combination of intense pre-clinical and clinicopathologic research along with neonatal neurology and quantitative neuroimaging research. In the following review, we explore literature relating the most frequently observed neuropathological patterns with the recent neuroimaging findings in preterm newborns and infants with perinatal brain injury. Specifically, we focus our discussions on the use of neuroimaging to aid diagnosis, measure morphometric brain damage, and track long-term neurodevelopmental outcomes.

MR imaging for accurate prediction of outcome after perinatal arterial ischemic stroke: Sooner not necessarily better

BACKGROUND

Involvement of the corticospinal tracts after perinatal arterial ischemic stroke (PAIS) is strongly correlated with adverse motor outcome.

METHODS

Two full-term infants with PAIS, with two early MRI scans available, are reported.

RESULTS

Diffusion weighted imaging (DWI)-MRI, performed within 24 h following onset of seizures and repeated 48 h later, clearly showed restricted diffusion within the middle cerebral artery territory on both MRIs, but clear patterns of signal intensity changes in the descending corticospinal tracts on the second MRI only.

CONCLUSION

Since involvement of the corticospinal tracts is essential for prediction of motor outcome, we may need to reconsider optimal timing of MR imaging for prediction of neurodevelopmental outcome after PAIS.

Erythropoietin and Brain Magnetic Resonance Imaging Findings in Hypoxic-Ischemic Encephalopathy: Volume of Acute Brain Injury and 1-Year Neurodevelopmental Outcome

In the Neonatal Erythropoietin and Therapeutic Hypothermia Outcomes study, 9/20 erythropoietin-treated vs 12/24 placebo-treated infants with hypoxic-ischemic encephalopathy had acute brain injury. Among infants with acute brain injury, the injury volume was lower in the erythropoietin than the placebo group (P = .004). Higher injury volume correlated with lower 12-month neurodevelopmental scores.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01913340.

Prognostic Value of Diffusion-Weighted Imaging (DWI) Apparent Diffusion Coefficient (ADC) in Patients with Hyperacute Cerebral Infarction Receiving rt-PA Intravenous Thrombolytic Therapy

BACKGROUND The aim of this study was to investigate the potential value of apparent diffusion coefficient (ADC) of diffusion-weighted imaging (DWI) in the prognosis of patients with hyperacute cerebral infarction (HCI) receiving intravenous thrombolytic therapy with recombinant tissue plasminogen activator (rt-PA). MATERIAL AND METHODS From June 2012 to June 2015, 58 cases of HCI (<6 h) undergoing rt-PA intravenous thrombolytic therapy (thrombolysis group) and 70 cases of HCI (<6 h) undergoing conventional antiplatelet and anticoagulant therapy (control group) in the same period were collected. DWI was conducted on all the subjects, and ADC maps were generated with Functool software to quantify ADC value. The clinical outcomes of HCI patients were observed for 3 months, and prognostic factors were analyzed. RESULTS Before thrombolysis treatment, the lesion area presented high signal intensity on DWI map and low signal intensity on ADC map, and gradually weakened signal intensity on DWI map and gradually enhanced signal intensity on ADC map were observed after thrombolysis. The ADC values of the thrombolysis group were significantly higher than those of the control group after treatment (24 h, 7 d, 30 d, and 90 d) (all P<0.05), and the ADC and rADC values in the thrombolysis group gradually increased over time (all P<0.05). Multiple logistic regression analysis showed that baseline National Institutes of Health Stroke Scale (NIHSS) score, baseline rADC value, and stroke history were the independent factors for the prognosis of HIC patients with thrombolysis (all P<0.05). CONCLUSIONS The values of ADC and rADC may provide guidance in the prognosis of HCI patients receiving rt-PA, and the baseline rADC value is the protective factor for the prognosis of HCI patients receiving rt-PA.

Paradoxical centrally increased diffusivity in perinatal arterial ischemic stroke

BACKGROUND

Restricted diffusion on acute MRI is the diagnostic standard for perinatal arterial ischemic stroke. In a subset of children with perinatal arterial ischemic stroke, primarily those with large infarct volumes, we noted a core of centrally increased diffusivity with a periphery of restricted diffusion.

OBJECTIVE

Given the paradoxical diffusion-weighted imaging (DWI) appearance observed in some children with perinatal arterial ischemic stroke, we sought to determine its significance and hypothesized that: (1) centrally increased diffusivity is associated with larger infarcts in perinatal arterial ischemic stroke and (2) this tissue is irreversibly injured (infarcted).

MATERIALS AND METHODS

We reviewed all perinatal arterial ischemic stroke cases in a prospective cohort study from Aug. 1, 2000, to Jan. 1, 2012. Infarct volumes were measured by drawing regions of interest around the periphery of the area of restricted diffusion on DWI. The Mann-Whitney U test was used to compare means between groups.

RESULTS

Of 25 eligible cases, centrally increased diffusivity was seen in 4 (16%). Cases with centrally increased diffusivity had larger average infarct volumes (mean 117,182 mm(3) vs. 36,995 mm(3); P = 0.008), higher average apparent diffusion coefficient (ADC) values in the infarct core (1,679 × 10(-6) mm(2)/s vs. 611 × 10(-6) mm(2)/s, P < 0.0001), and higher ADC ratio (1.2 vs. 0.5, P < 0.0001). At last clinical follow-up, children with perinatal arterial ischemic stroke and centrally increased diffusivity were more often treated for ongoing seizures (75% vs. 0%; P < 0.001) than those without.

CONCLUSION

Centrally increased diffusivity was associated with larger stroke volume and the involved tissue was confirmed to be infarcted on follow-up imaging. Radiologists should be aware of this unusual appearance of perinatal arterial ischemic stroke in order to avoid underestimating infarct volume or making an incorrect early diagnosis.

Therapeutic hypothermia modifies perinatal asphyxia-induced changes of the corpus callosum and outcome in neonates

What Is Known about this Subject?

Diffusion-weighted MRI has demonstrated changes in the corpus callosum of term neonates with perinatal asphyxia. The severity of cerebral changes demonstrated using diffusion-weighted MRI is difficult to assess without measuring values of the Apparent Diffusion Coefficient (ADC).

What Is New?

ADC values of the anterior part of the corpus callosum are slightly higher than of the posterior part in full term infants with perinatal asphyxia. Low ADC values of the corpus callosum were associated with an adverse outcome in infants with perinatal asphyxia. In infants treated with hypothermia lower ADC values than with normothermia were associated with a poor outcome, supporting neuroprotective effects of hypothermia

Background

Using MRI, changes can be detected in the corpus callosum (CC) following perinatal asphyxia which are associated with later neurodevelopmental outcome.

Aim

To study the association between the apparent diffusion coefficient of water (ADC) in the CC on MRI in neonates with perinatal asphyxia and neurodevelopmental outcome at 18 months of age.

Subjects, Methods

Of 121 infants 32 (26%) died and 13 (11%) survived with an adverse neurological outcome. Sixty-five (54%) received therapeutic hypothermia. MRI was performed within 7 days after birth using a 1.5 T or 3.0 T system, and ADC values were measured in the anterior and posterior CC. The association between ADC and composite outcome (death or abnormal neurodevelopment) was analyzed for both normothermia and hypothermia cases using receiver operating characteristics.

Results

ADC values of the posterior CC were lower than of the anterior part (mean difference 0.050 x 10^-3 mm²/s, p<0.001). Field strength did not affect ADC values. ADC values of the posterior part of the CC were significantly lower in infants with basal ganglia/thalamus or near total brain injury (p<0.001). Lower ADC values were associated with an adverse outcome, but cut-off levels were lower after hypothermia (1.024 x 10^-3 mm²/s vs 0.969 x 10^-3 mm²/s)

Conclusion

Low ADC values of the posterior part of the corpus callosum are associated with an adverse outcome in term or near term neonates with perinatal asphyxia. Therapeutic hypothermia slightly modifies this association, showing that lower values were needed for an adverse outcome.

Neonatal stroke: a review of the current evidence on epidemiology, pathogenesis, diagnostics and therapeutic options

Neonatal stroke, including perinatal arterial ischaemic stroke and cerebral sinovenous thrombosis, remains a serious problem in the neonate. This article reviews the current evidence on epidemiology, pathogenesis, diagnostics and therapeutic options.

CONCLUSION

Although our understanding of the underlying mechanisms and possible risk factors has improved, little progress has been made towards therapeutic options. Considering the high incidence of neurological sequelae, the need for therapeutic options is high and should be the focus of future research.